CENTENNIAL SPECIAL ARTICLE
Combined surgical-orthodontic treatment: How did it evolve and what are the best practices now? William R. Proffita and Raymond P. White, Jrb Chapel Hill, NC
It has been 50 years since the landmark presentation by Hugo Obwegeser at Walter Reed Army Hospital. At that conference, Professor Obwegeser offered American surgeons techniques to correct facial skeletal deformities with access through intraoral incisions. As important advances in surgical technique and anesthesia evolved for the surgical procedures, a major contribution by American orthodontists in collaboration with surgeons was the creation of a common diagnostic, planning, and treatment scheme for use by both clinician groups in the treatment of dentofacial deformities, the skeletal and dental problems of the most severely affected 5% of the population. This article summarizes what American orthodontists and surgeons have learned in the late 20th and early 21st centuries, and forecasts what might be the future of treatment for patients with dentofacial deformities. (Am J Orthod Dentofacial Orthop 2015;147:S205-15)
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lthough occasional mandibular surgery to set back the mandible was performed in the first half of the 20th century, modern orthognathic surgery began in the 1950s with the introduction of ramus osteotomy to reposition the tooth-bearing segments of the mandible. The use of a fixed orthodontic appliance for presurgical and postsurgical orthodontics and for stabilization at surgery followed quickly. The key surgical procedures, bilateral sagittal split ramus osteotomy (BSSO) and LeFort I down-fracture, were introduced in the 1960s, instigated by Professor Hugo Obwegeser, who showed American surgeons how to correct facial skeletal deformities through intraoral incisions. Since then, the combined efforts of orthodontists and surgeons have led to steady progress in efficient and
predictable treatment outcomes, with the options of 3-dimensional (3D) imaging and computer-assisted surgical planning the most recent advances. The purpose of this article is to provide an overview of how current surgical-orthodontic treatment evolved, with an emphasis on what has been learned about the controversial aspects of diagnosis and treatment planning, the coordination of orthodontic and surgical treatment, and computer applications for planning surgical procedures and evaluating outcomes. Although any prediction of the future is problematic, based on our collective experience we offer what we see evolving in the decades ahead as treatment for patients with dentofacial deformities. ORTHOGNATHIC SURGERY PROCEDURES
From the School of Dentistry, University of North Carolina, Chapel Hill, NC. a Kenan distinguished professor, Department of Orthodontics. b Dalton McMichael distinguished professor, Department of Oral and Maxillofacial Surgery. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Much of the information about treatment outcomes and stability came from studies funded by NIH grant DE-05215 from the National Institute of Dental Research. Address correspondence to: William R. Proffit, Department of Orthodontics, UNC School of Dentistry, Chapel Hill, NC 27599-7450; e-mail, William_Proffit@unc. edu. Submitted, revised and accepted, February 2015. 0889-5406/$36.00 Copyright Ó 2015 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2015.02.009
Most orthognathic surgery patients now are treated with 1 or both of 2 procedures developed in the late 1950s and 1960s: BSSO of the mandibular ramus1 and LeFort I osteotomy of the maxilla via down-fracture, refined by American surgeons.2,3 The basic technique of BSSO has not changed, but some important modifications have been introduced in recent years. The key element in this surgical procedure is the split within the ramus to obtain good bony apposition of the condylar and body segments after the body segment has been repositioned (Fig 1). The current emphasis is on completing the procedure with minimal S205
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Fig 1. A, Diagram of a BSSO showing the possibility of flaring the condyle-ramus segment unless a position screw is used; B, pattern of placement for screws; C, bone plate fixation across the osteotomy site, particularly useful if an unanticipated split occurs (from Proffit and White,4 with permission from Elsevier).
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trauma to the inferior alveolar nerve. The steps in the surgery and the critical elements are discussed in detail in current texts.4,5 As with BSSO, the basic technique of the LeFort I down-fracture remains unchanged, with important modifications through the years. Its critical element is osteotomy cuts that make down-fracture possible, giving access to superior structures so that segmentation of the maxilla and modifications in the nose are possible (Fig 2). This surgery also is described and illustrated in detail in current texts.4-6 The combination of these surgeries occurs frequently in current orthognathic surgery. In the later decades of the 20th century, lower border osteotomy of the mandible was added more often to the surgical plan. This procedure allows repositioning of the bony chin in all 3 planes of space (Fig 3). In contrast to BSSO and LeFort I down-fracture, it has not been widely presented in the orthodontic literature. In patients with true mandibular asymmetry, the chin often is deviated to 1 side more than the dentition is, and repositioning the chin along with a ramus osteotomy to achieve normal occlusion and symmetry often is preferred. The bony chin can be moved backward, but the limitation with backward movement is the relaxation of the soft tissues over the chin. The effect of backward movement can be an unesthetic wrinkling of the skin. Moving the chin forward or up can be achieved by angling the direction of the osteotomy cut upward; moving it down requires a bone graft but is quite feasible. A lower border osteotomy to move the chin upward and forward is termed a functional genioplasty because it allows normal lip function after correction of excessive chin height and inadequate chin projection. The procedure can be done at any time after the mandibular canines erupt. It is much less invasive than LeFort I or mandibular ramus surgery (Fig 4) and can greatly improve the functional and esthetic outcomes of orthodontic treatment for long-face Class II patients. An important recent finding is that bone remodeling above and behind the chin segment is better when this surgery is done before age 15 years than in older adolescents, and the results are better in older adolescents than in adults.7 Genioplasty is an underused component of comprehensive orthodontic treatment at present. With surgically assisted rapid palatal expansion (SARPE), transverse expansion of the maxilla is an important part of current orthodontic therapy. Before age 8 or 9 years, the midpalatal suture can be opened with a relatively light force delivered by a lingual arch
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Fig 2. A major advantage of the down-fracture technique for LeFort I osteotomy is the ability to reposition the maxilla in all 3 planes of space: A, diagram of the maxilla in the down-fractured position, showing the cuts needed to widen it and the resection of part of the cartilaginous nasal septum, which may be necessary in moving it superiorly; B, osteotomy cuts needed to retract the anterior maxillary segment into a premolar extraction site and simultaneously widen the posterior segments (from Proffit et al,5 with permission from Elsevier).
(jackscrew devices are contraindicated at those ages). By the beginning of adolescence, a heavier force from a jackscrew is needed to fracture overlapping bone spicules at the suture, and by late adolescence even a heavy force from a jackscrew is unlikely to open the suture. The original idea with SARPE was that making horizontal cuts in the lateral walls of the maxilla would reduce resistance to expansion enough to allow a fracture at the midpalatal suture. As the surgical technique developed, additional cuts were added to decrease the
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Fig 3. Inferior body osteotomy allows the chin to be repositioned in any plane of space. Angling the osteotomy cut upward allows simultaneous reduction of anterior face height and augmentation of chin prominence, an advantageous combination for long-face patients with a deficient chin; it is called functional genioplasty because it normalizes lip function (from Proffit and White,4 with permission from Elsevier).
chance of an uncontrolled fracture (which could have disastrous consequences such as uncontrolled bleeding without access to the ruptured vessels or sensory nerve damage). In the evolved technique, all the cuts needed for a LeFort I down-fracture seem necessary, even without completing the mobilization of the maxilla. SARPE, therefore, is not a minor surgical procedure. If the only thing a late adolescent or an adult patient needs is transverse expansion, it may be the preferred approach. If the patient would need a later LeFort I osteotomy for vertical or anteroposterior repositioning of the maxilla, SARPE is sometimes justified as the first stage of 2-stage surgery because the required maxillary expansion would be more stable than with a segmental maxillary osteotomy included in a 1-stage surgical plan. The best data now available indicate that the typical amount of skeletal expansion with SARPE is less than the expected 50% of the outcome with
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Fig 4. Diagrammatic view of combined LeFort I and BSSO, with bone plates for rigid fixation in the maxilla and bone screws in the mandible. This combination is used frequently in Class III correction and in Class II patients with long faces and mandibular deficiencies (from Proffit and White,4 with permission from Elsevier).
jackscrew expansion at earlier ages, and that there is significant relapse of the dental component of expansion.8 The presumably greater transverse stability of SARPE followed by LeFort I maxillary surgery is not an indication for avoiding segmental osteotomy for expansion with a LeFort I procedure. Treatment outcomes: short-term and long-term stability
Much of what had been learned during the 20th century about postsurgical stability with orthognathic procedures is summarized in chapter 12 of Contemporary Treatment of Dentofacial Deformity.4 There are 2 important points to keep in mind when stability is considered. 1.
Mean changes and statistical analysis based on the assumption of a normal distribution of outcomes after surgery tend to be misleading because a few patients typically have most of the changes. It often is more useful to discuss postsurgical stability with patients in terms of the percentage of patients who have clinically significant changes: ie, “Ms Jones, there are 4 chances out of 5 that you will have little or no postsurgical change, but you should understand that means there is a 20% chance of change toward your original jaw position.”
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Although it seems reasonable that postsurgical changes related to the surgery itself should be completed well within the first year, this simply is not true. Changes often continue to 5 years postsurgery and look as if the patient is having further growth in the pattern that produced the problem initially, even though he or she would seem too old to have that much growth.
Regarding Class II and Class III stability, during the first postsurgical year, the jaw relationship in patients who have had mandibular setback surgery tends to be unstable. In the past before rigid fixation was available, up to 50% had more than a 2-mm relapse forward in chin position, and 15% to 20% had greater than a 4mm change. The percentages have improved with rigid fixation, but still mandibular setback is a potentially problematic procedure. Mandibular stability is better in Class III patients who have 2-jaw surgery. For Class III patients with isolated maxillary advancement, there is an 80% chance of no significant change (\2 mm) in the postsurgery position of the maxilla and essentially no chance of more than a 4-mm change. In contrast, in patients who have mandibular advancement surgery with rigid fixation, there is a minimal (\5%) chance of greater than a 4-mm relapse at the chin in the first postsurgical year, and about a 20% chance of more than a 2-mm relapse, but almost as many patients have more than 2 mm of forward positioning of the chin. Patients with the most stable mandibular advancements are those who had downward movement of the chin to increase anterior face height. Rotation of the mandible superiorly to decrease anterior face height in a longface patient continues to be notoriously unstable without augmented fixation, and patients with this treatment need further documentation from larger case series before reliable and predictable outcomes evolve. The stability situation for orthognathic surgery reverses itself beyond 1 year; then the Class III patients are more stable than the mandibular advancement ones. Age at surgery is a factor. At 5-year recall, maxillary or 2-jaw surgery patients who were selected for early (adolescent) Class III surgery because mandibular growth had subsided to adult levels were as stable as older patients with the same surgery; both groups had about an 80% chance of less than a 2-mm change.9 In contrast, Class II patients treated with mandibular advancement surgery at ages when growth should have been completed were significantly more likely to have backward movement of the chin than those treated at an earlier age, but overjet was stable even if chin position changed because of mandibular incisor proclination when the mandible moved posteriorly.10
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Superior repositioning of the maxilla via LeFort I osteotomy was the first successful way to correct long-face and open-bite problems. Many of these patients also have a mandibular deficiency, and mandibular advancement is combined with moving the maxilla up. With rigid fixation this is quite stable during the first postsurgical year, but downward movement (growth) of the maxilla causes about a 20% chance of more than a 2-mm long-term increase in face height by the 5-year recall. The recent adoption of strategically placed bone plates or screws for skeletal anchorage allows orthodontic treatment to intrude the maxillary posterior teeth. This shows promise for the correction of less severe open bites (\6 mm of correction needed). Based on the data, at 1 and 2 years postintrusion its stability is similar to that of LeFort I surgery to close open bites.11 Interestingly, the amount of superior repositioning of the maxilla at surgery is not related to postsurgical stability. ORTHODONTIST AND SURGEON INTERACTIONS: WHO DOES WHAT, WHEN, AND WHY
Until the 1960s, surgeons and orthodontists tended to work independently to correct dentofacial deformities. It soon became apparent that there were problems if surgery was done first, and it was left to the orthodontist to finish the treatment. Neither the orthodontist nor the surgeon understood the other's treatment limitations. Orthodontists often had difficulty because the surgeon failed to position the jaw so that the orthodontist could adequately define the occlusion. Similar problems arose if the orthodontic treatment was done first and the surgeon had to complete the treatment. These problems were largely resolved by a treatment sequence that began with interactive treatment planning and continued with a pretreatment agreement on a sequence that involved orthodontic preparation for surgery, surgery with archwires used for stabilization, and a relatively short period of postsurgical orthodontic finishing. Planning to keep postsurgical treatment short appears to improve patient satisfaction with treatment.12 This remains the standard approach to comprehensive surgical-orthodontic treatment, although some clinicians now are again advocating surgery first (see discussion below). Interactive diagnosis and treatment planning
In the patient evaluation, most young adults with a dentofacial deformity are otherwise healthy. If so, a procedure under general anesthesia is not contraindicated. In practice, patients are often discharged to home on the day of surgery. Older patients who for various reasons have delayed treatment can have orthognathic
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surgery, even up to and beyond age 60 years. Obviously, these patients can have medical problems requiring adjustments to treatment plans, even to the extent of accepting less-than-ideal outcomes. All involved must understand this before treatment begins. Dentofacial proportions in potential surgical patients should be evaluated thoroughly, with a recommendation for orthognathic surgery or orthodontics alone based on the evaluation. Two-dimensional computer image predictions of profile changes from repositioning the jaws or the teeth are now reasonably accurate in nongrowing patients, who constitute most potential surgical patients. Imaging has been shown to improve the patient's understanding of the changes that would result from surgery or orthodontic camouflage (correcting the dental occlusion but not repositioning the jaws), without creating a risk of later claims of inadequate treatment, and make it easier for the treatment team to decide what combination of tooth movement and surgical repositioning would be optimal for the patient.13 An important question now is whether 3D imaging is needed to improve diagnosis and treatment planning for surgical patients. The guideline is reasonably straightforward: 3D radiographic imaging (typically cone-beam computed tomography) is so much better in the analysis of patients with major asymmetry that it now is the standard of care, and 3D photography for these patients is advantageous.14 By comparison, adequate diagnosis and initial treatment planning for most other surgery patients can be done with 2-dimensional cephalometric radiographs and photographs. For patients with temporomandibular joint problems, magnetic resonance imaging rather than radiographs of the joints is indicated. Three-dimensional radiographs also facilitate the surgical planning for patients with complex problems and may be needed at that stage, even though they were not used initially (see discussion below). A key question from the evaluation of dentofacial proportions is the extent to which orthodontic camouflage can meet the requirement of acceptable posttreatment facial appearance, without surgery. For Class III patients, orthodontic camouflage is a combination of forward movement of the maxillary teeth and retraction of the mandibular incisors. It can be quite successful in patients of Asian descent because they tend to have proclined mandibular incisors, but it is much less useful when the mandibular incisors are upright or tilted lingually, as they usually are in patients of European descent. Because retracting the mandibular incisors increases the relative prominence
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of the chin, this can make the facial appearance worse rather than better. Extracting the mandibular first premolars to provide space for a major retraction of the incisors is rarely a good idea; extracting 1 mandibular incisor allows modest retraction and often does not lead to the tooth-size discrepancy that might be expected. The discrepancy decreases and may even disappear with upright mandibular incisors and proclined maxillary incisors. Bone screws in the mandibular ramus can provide enough anchorage to retract the entire mandibular arch, although doing this requires extraction of the third molars and often the second molars as well. For Class II patients, camouflage is just the reverse: retraction of the maxillary incisors and proclination of the mandibular incisors. With skeletal anchorage, it is easy now to retract the maxillary incisors too much. They should not be retracted beyond the point that the upper lip is vertical—a backward slope of the lip is unesthetic. Proclination of the mandibular incisors can be camouflaged with genioplasty as described above (Fig 5), and genioplasty extends the amount of advancement of the mandibular incisors that can be compatible with a normal facial appearance. Presurgical orthodontic treatment
If the incisors are not reasonably well aligned at surgery, it can be difficult to surgically position the jaws as desired because irregular teeth create dental interferences in the new jaw positions. For this reason, alignment is the first step in presurgical treatment— unless the teeth already are reasonably well aligned, as they sometimes are in patients who need jaw surgery. In that case, the presurgical treatment time can be quite short. A key step in planning alignment, of course, is whether arch expansion, extraction, or interproximal stripping should be used to gain enough space. That decision relates directly to how to achieve the next presurgical goal. Establishment of anteroposterior and vertical incisor positions
Often, even if the teeth are well aligned, dental compensation for the jaw discrepancy has led to a dental occlusion in which the teeth fit better than the jaws. In a skeletal Class III malocclusion, the maxillary incisors are likely to be proclined and the mandibular incisors upright, even before any orthodontic treatment. The opposite is seen in skeletal Class II patients, in whom proclination of the mandibular incisors often develops
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during growth. If the dental compensation is not removed before surgery, the jaw correction will be inadequate when the surgeon brings the teeth into occlusion as the jaw is repositioned. The guideline is that the presurgical movement of retruded or proclined incisors should be at least a 100% correction or slightly more if possible, because inevitably there will be some relapse toward the original incisor position. Overeruption of the incisors often partially compensates for the severity of an anterior open bite in longface patients, and intrusion of the incisors is needed to correct this before surgery. In long-face patients who are being prepared for vertical repositioning of the maxilla, it is almost always a serious mistake to elongate the incisors while leveling the dental arches. This would increase an incisor display that is already excessive and build in an unfortunate relapse tendency that can lead to posttreatment bite opening. In short-face deepbite patients, dental compensation is less frequent, and often excessive eruption of the mandibular incisors and accentuation of the curve of Spee occur. Is intrusion of these incisors needed? That depends on the face height desired after surgery, because posttreatment anterior face height is determined by the vertical position of the incisors. When an increase in face height is needed, leveling the mandibular arch mainly by elongating the canines and the premolars often is the best treatment plan. For these patients, it is best to simply align the arch without presurgical leveling and complete the leveling postsurgically when the teeth that need to be extruded are no longer in occlusion. Other presurgical orthodontic treatments
For many patients, the maxillary arch form needs to be made compatible with the mandibular arch form before surgery. Failure to do that leads to canine interferences as the teeth are brought into occlusion at surgery. Arch form compatibility in Class II patients can be estimated by having the patient bite forward, but for Class III patients, dental casts to check compatibility are required. Sometimes, it is easier to understand what needs to be accomplished by considering what is not needed. Intrusion of teeth must be done presurgically, but extrusion often can be done more easily postsurgically. Correction of minor (half cusp) crossbites that would exist after repositioning of the jaws can be done postsurgically; major ones (full cusp) need presurgical correction. Extraction sites should be closed before surgery unless segmental osteotomies will be used to
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Fig 5. Dentofacial changes after functional genioplasty to bring the chin upward and forward: A and B, after extensive orthodontic treatment that resulted in good dental alignment and occlusion but did not control long face growth; C and D, 6 months after surgery. Note that the lower lip moved up along with the chin, allowing lip closure in function and eliminating the display of the mandibular incisors that was not appropriate for a 14-year-old girl.
close them, but root paralleling can be finished postsurgically. The overall goal must be kept in mind: get the presurgical arrangement of the teeth to the point that postsurgical orthodontic treatment will not take more than 6 months—and don't waste a lot of time trying to perfect the occlusion presurgically. Some postsurgical orthodontic treatment will be needed for every patient. Final surgical planning
The orthodontist and the surgeon should communicate on progress toward surgery throughout the presurgical orthodontic phase of treatment. Consensus on the
patient's readiness for surgery should be reached at least 3 months before the surgery date. Hospital schedules depend on insurance approvals, which often must be confirmed by submitting added patient information. In addition, both clinicians should agree on the presurgery tooth alignment and the desired jaw position after surgery. Unfortunately, this communication between the orthodontist and the surgeon often is forgotten or delayed until too close to the surgery date, causing problems that include less-than-optimal outcomes. Inadequate canine or molar expansion that limits the surgeon's ability to position the teeth and the jaws in the ideal position is a frequent problem, created because
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presurgical models were not obtained before sending the patient to the surgeon. Three-dimensional imaging now plays an increasing role in the final surgical planning because software and technical support allow the surgeon to do this without the articulator-mounted casts needed previously for model surgery. The software allows a cranial base registration, from which the surgeon can see planned movements and the interaction between the surgical segments from any perspective. This has 3 advantages: it makes it easy to evaluate several possibilities in positioning the segments without having to do repeated model surgeries; it allows the surgeon to visualize how proximal and distal segments will approximate so that condylar torque can be reduced (which is especially important in patients with asymmetry); and it eliminates the need to make surgical splints with repositioned dental casts. The splints can be formulated accurately from the final positions of the virtual segments as anatomically correct stereolithographic models. If skeletal anchorage would be needed for postsurgical tooth movement, positioning the screws or bone planes also can be part of the surgical plan. The combination of these advantages makes model surgery easier and more efficient, especially for complex cases. Whether this justifies the additional radiation and cost has not yet been clearly established.
A patient having orthognathic surgery is managed by the surgeon and the anesthesiologist from the point that the patient is deemed ready for surgery until he or she is discharged from the surgical facility. Management by the surgeon (which includes elastics to help the patient adapt to the new jaw position) continues until the patient is judged ready to resume active orthodontic treatment.
Mistakes of the past include leaving stabilizing archwires in place after removal of the splint and omitting elastics with the first postsurgical archwires. The goal of the elastics is not to move the teeth—the archwires can do that. We have learned that without guiding elastics, a slide in jaw position from initial contact to an acquired position often develops, and this is difficult to eliminate if it occurs. The working archwires usually consist of a flexible rectangular archwire in one arch (the one in which tooth orientation needs to be maintained, usually the maxillary arch) and a round wire in the other arch (where more tooth movement is needed). For postsurgical orthodontic treatment, monthly appointments seem to be the best choice. More frequent appointments carry with them a risk of damage to the teeth or periodontal structures; longer ones delay the completion of treatment. The goals are to complete the orthodontic treatment and remove the appliances in 4 to 5 months after the surgery. If postsurgical treatment takes longer than 6 months, presurgical preparation was inadequate. Retention for surgical patients is not different from retention generally, with 1 exception: maxillary expansion with segmental surgery is not stable for 6 to 8 months after surgery. We have learned that expansion must be maintained during the postsurgical orthodontic treatment and after the appliances are removed. A suck-down retainer placed immediately after appliance removal seems prudent, rather than waiting until a laboratory can make a wire or an acrylic retainer. This short-term option can be replaced with a retainer with palatal coverage later, but after surgical expansion, full-time retainer wear is needed for up to 8 months postsurgery. Then part-time retainer wear for at least another 4 to 6 months has proven to be beneficial.
Postsurgical orthodontic treatment
Surgery first?
The goal of postsurgical orthodontic treatment is straightforward: bring the teeth into occlusion while correcting minor discrepancies and helping the patient adapt to the new jaw and occlusal relationships. The use of rigid fixation devices to stabilize repositioned facial bones and facilitate healing has assisted the orthodontist, allowing earlier treatment postsurgery without the fear of disturbing the new jaw positions, but the surgeon's judgment should determine when active orthodontic treatment resumes. At that point, flexible working archwires are placed, and the patient should wear light posterior vertical elastics full time until the next appointment.
Recently, it has been suggested that with modern technology and techniques, surgery first once again should be considered, at least for selected patients, with the primary goal to shorten the total treatment time. Without data for treatment outcomes for this approach, it is too early to adopt it over a sequence with known positive outcomes. As noted above, studies of the psychological response to orthognathic surgery have shown that at 6 months postsurgery, patients begin to be increasingly stressed by continued orthodontic treatment. Even with selected patients, postsurgical treatment times with surgery first extend well beyond that time.
Patient management in the perioperative period
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Limitations in magnitude and direction of surgical movements
At this point, the combination of orthodontic treatment and orthognathic surgery allows almost every surgical movement that would be desired, but with limitations in some directions and in the distances of movement. We summarize with the following. 1.
2.
3.
4.
The maxilla can be moved forward about 6 mm before stability becomes a problem. Moving the whole maxilla back is possible, but is quite difficult and unnecessary in any case because the anterior segment can be moved back if protrusion of the incisors is excessive. It can be stably moved up for almost any patient farther than is compatible with acceptable incisor display, and this is the limitation for superior repositioning. Short-term stability is a problem with moving the posterior maxilla down, but rotating it down anteriorly to increase incisor display is not. The mandible can be moved forward or backward, but backward movement is predictably unstable, and with either forward or backward movement, moving the gonial angle down (increasing ramus height and decreasing the mandibular plane angle) is a prescription for relapse into an anterior open bite because of a lack of muscle adaptation. Rotation in the other direction, increasing anterior face height and the mandibular plane angle, is quite stable. Alveolar segments can be moved in any direction and can be expected to be stable if the segment was not too small and good bony contact was maintained; this, of course, imposes limits on the amount of movement. The same guidelines apply to repositioning the chin, discussed above.
A 21ST CENTURY PERSPECTIVE: WHAT DOES THE FUTURE HOLD?
Our ability to predict the future is no more accurate than other knowledgeable clinicians, but current trends do offer probable outcomes for at least the next decade and perhaps longer. Based on U.S. population data in 2010, more than 2 million people ages 15 to 19 years live in our country (U.S. Census Bureau, 2010 data). The 1975 report from a study by the National Academy of Sciences estimated that as many as 5% of American adolescents might have a “handicapping malocclusion,” which we now call a dentofacial deformity.15 If half of those would need orthgnathic surgery, this suggests that at least 500,000 adolescents might require evaluation for orthognathic surgery annually. No obvious
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reason exists for a future decrease in the numbers in this affected target population. We suggest that the following factors at least will influence how affected persons will get evaluation and treatment if needed. Although interrelated, the determining factors will be considered separately: education of providers, clinical sites for treatment, practice patterns of treating clinicians, impact of health insurance on access to care, and shifts in the commitment of the United States to provide care for all or most of the population. Education of providers
Referrals for evaluation of young adults with a dentofacial deformity should arise from primary care physicians and general dentists. Although some efforts are emerging to educate physicians on oral health issues, for the near future we must assume that current physicians as a group will not routinely refer those in need for evaluation, even though the trend with the Affordable Care Act is to require physician referrals for evaluation and possible treatment involving any surgery. In most dental schools, students are exposed to aspects of combined treatment by orthodontists and surgeons in orthognathic surgery. The educational exposure is not uniform. Currently, general dentists, even if knowledgeable, have little incentive to refer affected patients for evaluation of combined surgicalorthodontic treatment, particularly if the unknowing patient or family is unaware of treatment options. A concerted effort by the American Association of Orthodontists and the American Association of Oral and Maxillofacial Surgeons could raise awareness of this issue, but practice patterns that we describe later mitigate that as a priority for either group. In contrast, most orthodontists and surgeons in training and practice have had the opportunity to treat patients with dentofacial deformities; this is clearly different from only a few decades ago and is a positive trend for the future. Clinical sites for treatment
Orthodontic clinical sites in both community practices and academic centers are equipped to provide the needed evaluation and treatment services for persons with dentofacial deformities. Unless the patients are the focus of a community practice of oral and maxillofacial surgery, surgery practices are not equipped for the needed evaluations. This deficit is not insurmountable, assuming that surgeons are willing to collaborate on a regular basis with orthodontists. However, evolving practice patterns in the community offer little promise that the collaborations will routinely or easily occur.
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Orthognathic surgery has become efficient and effective today. Performing the surgery does require both a surgeon trained in and familiar with current techniques and an anesthesiologist familiar with the patient's needs and willing to provide anesthesia services. For the most part today, either a specially equipped ambulatory surgical center with recovery services able to meet the special needs of these patients or an appropriately equipped hospital operating room is required. The volume of patients is important to both entities. Investing in the required instruments and devices is not cost-effective otherwise. This suggests a concentration of orthognathic surgeries in selected clinical sites and an impact on which surgeons perform the surgeries. Practice patterns of treating clinicians
Most orthodontists are adequately trained to offer orthodontic services to patients with dentofacial deformities. Almost all orthodontists will see at least a few affected patients in their community practices. Some find care of these patients rewarding and challenging, perhaps different enough to maintain the clinician's interest. If sufficient interest is widely known, affected patients may tend to concentrate in certain orthodontic practices. Barriers to orthodontists' willingness to treat these patients include the required collaboration for each patient over time with surgeons who may not be geographically near, added liability for less-thandesired outcomes, complicated processes for insurance approvals, and the extra hassle of treating patients who require differing treatment protocols. That said, the rewards of successfully treating patients with dentofacial deformities make it likely that enough orthodontists will be available to care for any projected numbers of patients seeking treatment. The situation for surgeons is quite different. Almost all are trained for orthognathic surgery and capable of treating all but the most difficult patients upon completing residency. At this point, the practice patterns of surgeons diverge. Many if not most surgeons today in community practices do not have a regular schedule for hospital surgery and do not work more than occasionally in the hospital. The reasons are many. If the surgeon has a dedicated ambulatory facility, it must be staffed heavily with salaries supported by the patients treated. Insurance carriers have deduced that low surgery fees discourage surgeons from treating complicated patients. In a short time if few patients are treated, the surgeon has little incentive to continue performing orthognathic surgery. Exceptions exist; a few community practices actively seek patients with dentofacial deformities. Working relationships with certain orthodontists are courted, making
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collaboration easy. Dedicated ambulatory surgery sites are designed, equipped, and staffed to care for patients before and after surgery. The staff are specially trained to assist the surgeons and anesthesiologists. However, we suggest that most orthognathic surgery in the future will be performed in academic medical centers whose hospitals are equipped and staffed for the patients' needs. Under this outcome, surgeons will have the needed volume of patients to be current with methods and meet the requirements to maintain hospital privileges. Impact of health insurance on access to care
A curious and perhaps predictable reaction from insurance carriers has evolved on paying for orthognathic surgery. Orthodontic care continues to be “self-pay” or paid for by a combination of dental insurance and copayments. There is little adjustment or accommodation for the complexity of care. This pattern is likely to continue for orthodontics, and no trend is seen for more patients having some form of dental insurance. At the outset in the 1980s, medical insurance covered orthognathic surgery similar to orthopedic and other surgery. As the numbers of patients treated increased with the advent of effective surgery, insurance carriers saw increasing outlays of their premium dollars. To discourage claims, the carriers first claimed that orthognathic surgery did not meet their definition of “medical necessity.” About the same time, the U.S. Surgeon General and the World Health Organization called attention to quality-of-life outcomes being as important as “medical” outcomes. Clearly, orthognathic surgery patients benefitted from improved quality of life, and the change in quality of life outcomes as the medical criterion made “medical necessity” moot, but some, although fewer, carriers offer this today as a reason to deny claims. The current strategy of insurance carriers is quite effective in limiting outlays for orthognathic surgery. Surgeons are paid at ridiculously low levels and cannot bill patients beyond this level as a requirement of being in the carrier's network. This contributes to having orthognathic surgery concentrated in a few centers. As hospital consolidations continue, which is required for hospitals to be large enough to counter the economic influence of insurance carriers and the pharmaceutical industry, surgical services including orthognathic surgery will be concentrated at fewer sites, with patients treated by surgeons hired specifically for that purpose. Commitment to provide health care for the population
By many measures, health care in the United States is a nonsystem and a failure in comparison with other
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developed countries. For economic reasons alone, things will change. We cannot afford the current trend in expenditures as a nation. Much will depend on political maneuvering and priorities based on economics. Examples abound, including the several states that refused to expand Medicaid services. Where will orthognathic surgery rank in priority compared with other procedures to improve quality of life such as orthopedic surgery for arthroscopy or joint replacement? Advocates for orthognathic surgery will first be the consolidated hospital centers that have effectively concentrated services in selected sites. They have made a commitment to maintain orthognathic surgical services similar to other surgical services, cardiac and orthopedic among them. We cannot predict how strong an advocacy we might expect from the American Dental Association, the American Association of Orthodontists, or the American Association of Oral and Maxillofacial Surgeons. Even if committed, their advocacy has had a mixed outcome in the past. Unfortunately, other health care advocacy groups know little about dentofacial deformities; this certainly is not helped by the division in education for dentists and physicians. Perhaps the most compelling reason for believing that orthognathic services will continue in the future is the number of affected young adults who can benefit from treatment. As we commented at the outset, predicting the future is problematic. However, we hope we have offered “food for thought” as the future comes upon us. REFERENCES 1. Trauner R, Obwegezer H. The surgical correction of mandibular prognathism and retrognathia with consideration of genioplasty. Oral Surg Oral Med Oral Pathol 1957;10:787-92.
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2. Bell WH. LeFort I osteotomy for correction of maxillary deformities. J Oral Surg 1975;33:412-26. 3. Epker BN, Wolford LM. Middle third facial osteotomies: their use in correction of acquired and developmental deformities. J Oral Surg 1975;33:491-514. 4. Proffit WR, White RP Jr. Contemporary treatment of dentofacial deformity. St Louis: Elsevier; 2003. (now available in electronic edition only). 5. Proffit WR, Fields HW Jr, Sarver DM. Contemporary orthodontics. 5th ed. St Louis: Elsevier; 2013. 6. Posnick JC. Orthognathic surgery: Principles and practice. St Louis: Elsevier; 2014. 7. Chamberland S, Proffit WR, Chamberland PE. Functional genioplasty in growing patients. Angle Orthod 2014 [Epub ahead of print]. 8. Chamberland S, Proffit WR. Short-term and long-term stability of surgically assisted rapid palatal expansion revisited. Am J Orthod Dentofacial Orthop 2011;139:815-22. 9. Bailey LJ, Phillips C, Proffit WR. Long-term outcome of surgical Class III correction as a function of age at surgery. Am J Orthod Dentofacial Orthop 2008;133:365-70. 10. Proffit WR, Phillips C, Turvey TA. Long-term stability of adolescent versus adult surgery for treatment of mandibular deficiency. Int J Oral Maxillofac Surg 2010;39:327-32. 11. Scheffler NR, Proffit WR, Phillips C. Outcomes and stability in patients with anterior open bite and long anterior face height treated with temporary anchorage devices and a maxillary intrusion splint. Am J Orthod Dentofacial Orthop 2014;146:594-602. 12. Kiyak HA, McNeill RW, West RA, Hohl T, Bucher F, Sherrick P. Predicting psychologic responses to orthognathic surgery. J Oral Maxillofac Surg 1980;40:150-5. 13. Phillips C, Hill BJ, Cannac C. The influence of video imaging on patients’ perceptions and expectations. Angle Orthod 1995;65: 263-70. 14. Jackson TH, Mitroff SR, Clark K, Proffit WR, Lee JY, Nguyen TT. Face symmetry assessment abilities: clinical implications for diagnosing asymmetry. Am J Orthod Dentofacial Orthop 2013;144: 663-71. 15. Morris AL, et al. Handicapping orthodontic conditions. Washington DC: National Academy of Sciences; 1975.
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Combined surgical-orthodontic treatment: How did it evolve and what are the best practices now? William R. Proffita and Raymond P. White, Jrb Chapel Hill, NC
It has been 50 years since the landmark presentation by Hugo Obwegeser at Walter Reed Army Hospital. At that conference, Professor Obwegeser offered American surgeons techniques to correct facial skeletal deformities with access through intraoral incisions. As important advances in surgical technique and anesthesia evolved for the surgical procedures, a major contribution by American orthodontists in collaboration with surgeons was the creation of a common diagnostic, planning, and treatment scheme for use by both clinician groups in the treatment of dentofacial deformities, the skeletal and dental problems of the most severely affected 5% of the population. This article summarizes what American orthodontists and surgeons have learned in the late 20th and early 21st centuries, and forecasts what might be the future of treatment for patients with dentofacial deformities. (Am J Orthod Dentofacial Orthop 2015;147:S205-15)
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lthough occasional mandibular surgery to set back the mandible was performed in the first half of the 20th century, modern orthognathic surgery began in the 1950s with the introduction of ramus osteotomy to reposition the tooth-bearing segments of the mandible. The use of a fixed orthodontic appliance for presurgical and postsurgical orthodontics and for stabilization at surgery followed quickly. The key surgical procedures, bilateral sagittal split ramus osteotomy (BSSO) and LeFort I down-fracture, were introduced in the 1960s, instigated by Professor Hugo Obwegeser, who showed American surgeons how to correct facial skeletal deformities through intraoral incisions. Since then, the combined efforts of orthodontists and surgeons have led to steady progress in efficient and
predictable treatment outcomes, with the options of 3-dimensional (3D) imaging and computer-assisted surgical planning the most recent advances. The purpose of this article is to provide an overview of how current surgical-orthodontic treatment evolved, with an emphasis on what has been learned about the controversial aspects of diagnosis and treatment planning, the coordination of orthodontic and surgical treatment, and computer applications for planning surgical procedures and evaluating outcomes. Although any prediction of the future is problematic, based on our collective experience we offer what we see evolving in the decades ahead as treatment for patients with dentofacial deformities. ORTHOGNATHIC SURGERY PROCEDURES
From the School of Dentistry, University of North Carolina, Chapel Hill, NC. a Kenan distinguished professor, Department of Orthodontics. b Dalton McMichael distinguished professor, Department of Oral and Maxillofacial Surgery. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Much of the information about treatment outcomes and stability came from studies funded by NIH grant DE-05215 from the National Institute of Dental Research. Address correspondence to: William R. Proffit, Department of Orthodontics, UNC School of Dentistry, Chapel Hill, NC 27599-7450; e-mail, William_Proffit@unc. edu. Submitted, revised and accepted, February 2015. 0889-5406/$36.00 Copyright Ó 2015 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2015.02.009
Most orthognathic surgery patients now are treated with 1 or both of 2 procedures developed in the late 1950s and 1960s: BSSO of the mandibular ramus1 and LeFort I osteotomy of the maxilla via down-fracture, refined by American surgeons.2,3 The basic technique of BSSO has not changed, but some important modifications have been introduced in recent years. The key element in this surgical procedure is the split within the ramus to obtain good bony apposition of the condylar and body segments after the body segment has been repositioned (Fig 1). The current emphasis is on completing the procedure with minimal S205
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Fig 1. A, Diagram of a BSSO showing the possibility of flaring the condyle-ramus segment unless a position screw is used; B, pattern of placement for screws; C, bone plate fixation across the osteotomy site, particularly useful if an unanticipated split occurs (from Proffit and White,4 with permission from Elsevier).
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trauma to the inferior alveolar nerve. The steps in the surgery and the critical elements are discussed in detail in current texts.4,5 As with BSSO, the basic technique of the LeFort I down-fracture remains unchanged, with important modifications through the years. Its critical element is osteotomy cuts that make down-fracture possible, giving access to superior structures so that segmentation of the maxilla and modifications in the nose are possible (Fig 2). This surgery also is described and illustrated in detail in current texts.4-6 The combination of these surgeries occurs frequently in current orthognathic surgery. In the later decades of the 20th century, lower border osteotomy of the mandible was added more often to the surgical plan. This procedure allows repositioning of the bony chin in all 3 planes of space (Fig 3). In contrast to BSSO and LeFort I down-fracture, it has not been widely presented in the orthodontic literature. In patients with true mandibular asymmetry, the chin often is deviated to 1 side more than the dentition is, and repositioning the chin along with a ramus osteotomy to achieve normal occlusion and symmetry often is preferred. The bony chin can be moved backward, but the limitation with backward movement is the relaxation of the soft tissues over the chin. The effect of backward movement can be an unesthetic wrinkling of the skin. Moving the chin forward or up can be achieved by angling the direction of the osteotomy cut upward; moving it down requires a bone graft but is quite feasible. A lower border osteotomy to move the chin upward and forward is termed a functional genioplasty because it allows normal lip function after correction of excessive chin height and inadequate chin projection. The procedure can be done at any time after the mandibular canines erupt. It is much less invasive than LeFort I or mandibular ramus surgery (Fig 4) and can greatly improve the functional and esthetic outcomes of orthodontic treatment for long-face Class II patients. An important recent finding is that bone remodeling above and behind the chin segment is better when this surgery is done before age 15 years than in older adolescents, and the results are better in older adolescents than in adults.7 Genioplasty is an underused component of comprehensive orthodontic treatment at present. With surgically assisted rapid palatal expansion (SARPE), transverse expansion of the maxilla is an important part of current orthodontic therapy. Before age 8 or 9 years, the midpalatal suture can be opened with a relatively light force delivered by a lingual arch
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Fig 2. A major advantage of the down-fracture technique for LeFort I osteotomy is the ability to reposition the maxilla in all 3 planes of space: A, diagram of the maxilla in the down-fractured position, showing the cuts needed to widen it and the resection of part of the cartilaginous nasal septum, which may be necessary in moving it superiorly; B, osteotomy cuts needed to retract the anterior maxillary segment into a premolar extraction site and simultaneously widen the posterior segments (from Proffit et al,5 with permission from Elsevier).
(jackscrew devices are contraindicated at those ages). By the beginning of adolescence, a heavier force from a jackscrew is needed to fracture overlapping bone spicules at the suture, and by late adolescence even a heavy force from a jackscrew is unlikely to open the suture. The original idea with SARPE was that making horizontal cuts in the lateral walls of the maxilla would reduce resistance to expansion enough to allow a fracture at the midpalatal suture. As the surgical technique developed, additional cuts were added to decrease the
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Fig 3. Inferior body osteotomy allows the chin to be repositioned in any plane of space. Angling the osteotomy cut upward allows simultaneous reduction of anterior face height and augmentation of chin prominence, an advantageous combination for long-face patients with a deficient chin; it is called functional genioplasty because it normalizes lip function (from Proffit and White,4 with permission from Elsevier).
chance of an uncontrolled fracture (which could have disastrous consequences such as uncontrolled bleeding without access to the ruptured vessels or sensory nerve damage). In the evolved technique, all the cuts needed for a LeFort I down-fracture seem necessary, even without completing the mobilization of the maxilla. SARPE, therefore, is not a minor surgical procedure. If the only thing a late adolescent or an adult patient needs is transverse expansion, it may be the preferred approach. If the patient would need a later LeFort I osteotomy for vertical or anteroposterior repositioning of the maxilla, SARPE is sometimes justified as the first stage of 2-stage surgery because the required maxillary expansion would be more stable than with a segmental maxillary osteotomy included in a 1-stage surgical plan. The best data now available indicate that the typical amount of skeletal expansion with SARPE is less than the expected 50% of the outcome with
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2.
Fig 4. Diagrammatic view of combined LeFort I and BSSO, with bone plates for rigid fixation in the maxilla and bone screws in the mandible. This combination is used frequently in Class III correction and in Class II patients with long faces and mandibular deficiencies (from Proffit and White,4 with permission from Elsevier).
jackscrew expansion at earlier ages, and that there is significant relapse of the dental component of expansion.8 The presumably greater transverse stability of SARPE followed by LeFort I maxillary surgery is not an indication for avoiding segmental osteotomy for expansion with a LeFort I procedure. Treatment outcomes: short-term and long-term stability
Much of what had been learned during the 20th century about postsurgical stability with orthognathic procedures is summarized in chapter 12 of Contemporary Treatment of Dentofacial Deformity.4 There are 2 important points to keep in mind when stability is considered. 1.
Mean changes and statistical analysis based on the assumption of a normal distribution of outcomes after surgery tend to be misleading because a few patients typically have most of the changes. It often is more useful to discuss postsurgical stability with patients in terms of the percentage of patients who have clinically significant changes: ie, “Ms Jones, there are 4 chances out of 5 that you will have little or no postsurgical change, but you should understand that means there is a 20% chance of change toward your original jaw position.”
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Although it seems reasonable that postsurgical changes related to the surgery itself should be completed well within the first year, this simply is not true. Changes often continue to 5 years postsurgery and look as if the patient is having further growth in the pattern that produced the problem initially, even though he or she would seem too old to have that much growth.
Regarding Class II and Class III stability, during the first postsurgical year, the jaw relationship in patients who have had mandibular setback surgery tends to be unstable. In the past before rigid fixation was available, up to 50% had more than a 2-mm relapse forward in chin position, and 15% to 20% had greater than a 4mm change. The percentages have improved with rigid fixation, but still mandibular setback is a potentially problematic procedure. Mandibular stability is better in Class III patients who have 2-jaw surgery. For Class III patients with isolated maxillary advancement, there is an 80% chance of no significant change (\2 mm) in the postsurgery position of the maxilla and essentially no chance of more than a 4-mm change. In contrast, in patients who have mandibular advancement surgery with rigid fixation, there is a minimal (\5%) chance of greater than a 4-mm relapse at the chin in the first postsurgical year, and about a 20% chance of more than a 2-mm relapse, but almost as many patients have more than 2 mm of forward positioning of the chin. Patients with the most stable mandibular advancements are those who had downward movement of the chin to increase anterior face height. Rotation of the mandible superiorly to decrease anterior face height in a longface patient continues to be notoriously unstable without augmented fixation, and patients with this treatment need further documentation from larger case series before reliable and predictable outcomes evolve. The stability situation for orthognathic surgery reverses itself beyond 1 year; then the Class III patients are more stable than the mandibular advancement ones. Age at surgery is a factor. At 5-year recall, maxillary or 2-jaw surgery patients who were selected for early (adolescent) Class III surgery because mandibular growth had subsided to adult levels were as stable as older patients with the same surgery; both groups had about an 80% chance of less than a 2-mm change.9 In contrast, Class II patients treated with mandibular advancement surgery at ages when growth should have been completed were significantly more likely to have backward movement of the chin than those treated at an earlier age, but overjet was stable even if chin position changed because of mandibular incisor proclination when the mandible moved posteriorly.10
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Superior repositioning of the maxilla via LeFort I osteotomy was the first successful way to correct long-face and open-bite problems. Many of these patients also have a mandibular deficiency, and mandibular advancement is combined with moving the maxilla up. With rigid fixation this is quite stable during the first postsurgical year, but downward movement (growth) of the maxilla causes about a 20% chance of more than a 2-mm long-term increase in face height by the 5-year recall. The recent adoption of strategically placed bone plates or screws for skeletal anchorage allows orthodontic treatment to intrude the maxillary posterior teeth. This shows promise for the correction of less severe open bites (\6 mm of correction needed). Based on the data, at 1 and 2 years postintrusion its stability is similar to that of LeFort I surgery to close open bites.11 Interestingly, the amount of superior repositioning of the maxilla at surgery is not related to postsurgical stability. ORTHODONTIST AND SURGEON INTERACTIONS: WHO DOES WHAT, WHEN, AND WHY
Until the 1960s, surgeons and orthodontists tended to work independently to correct dentofacial deformities. It soon became apparent that there were problems if surgery was done first, and it was left to the orthodontist to finish the treatment. Neither the orthodontist nor the surgeon understood the other's treatment limitations. Orthodontists often had difficulty because the surgeon failed to position the jaw so that the orthodontist could adequately define the occlusion. Similar problems arose if the orthodontic treatment was done first and the surgeon had to complete the treatment. These problems were largely resolved by a treatment sequence that began with interactive treatment planning and continued with a pretreatment agreement on a sequence that involved orthodontic preparation for surgery, surgery with archwires used for stabilization, and a relatively short period of postsurgical orthodontic finishing. Planning to keep postsurgical treatment short appears to improve patient satisfaction with treatment.12 This remains the standard approach to comprehensive surgical-orthodontic treatment, although some clinicians now are again advocating surgery first (see discussion below). Interactive diagnosis and treatment planning
In the patient evaluation, most young adults with a dentofacial deformity are otherwise healthy. If so, a procedure under general anesthesia is not contraindicated. In practice, patients are often discharged to home on the day of surgery. Older patients who for various reasons have delayed treatment can have orthognathic
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surgery, even up to and beyond age 60 years. Obviously, these patients can have medical problems requiring adjustments to treatment plans, even to the extent of accepting less-than-ideal outcomes. All involved must understand this before treatment begins. Dentofacial proportions in potential surgical patients should be evaluated thoroughly, with a recommendation for orthognathic surgery or orthodontics alone based on the evaluation. Two-dimensional computer image predictions of profile changes from repositioning the jaws or the teeth are now reasonably accurate in nongrowing patients, who constitute most potential surgical patients. Imaging has been shown to improve the patient's understanding of the changes that would result from surgery or orthodontic camouflage (correcting the dental occlusion but not repositioning the jaws), without creating a risk of later claims of inadequate treatment, and make it easier for the treatment team to decide what combination of tooth movement and surgical repositioning would be optimal for the patient.13 An important question now is whether 3D imaging is needed to improve diagnosis and treatment planning for surgical patients. The guideline is reasonably straightforward: 3D radiographic imaging (typically cone-beam computed tomography) is so much better in the analysis of patients with major asymmetry that it now is the standard of care, and 3D photography for these patients is advantageous.14 By comparison, adequate diagnosis and initial treatment planning for most other surgery patients can be done with 2-dimensional cephalometric radiographs and photographs. For patients with temporomandibular joint problems, magnetic resonance imaging rather than radiographs of the joints is indicated. Three-dimensional radiographs also facilitate the surgical planning for patients with complex problems and may be needed at that stage, even though they were not used initially (see discussion below). A key question from the evaluation of dentofacial proportions is the extent to which orthodontic camouflage can meet the requirement of acceptable posttreatment facial appearance, without surgery. For Class III patients, orthodontic camouflage is a combination of forward movement of the maxillary teeth and retraction of the mandibular incisors. It can be quite successful in patients of Asian descent because they tend to have proclined mandibular incisors, but it is much less useful when the mandibular incisors are upright or tilted lingually, as they usually are in patients of European descent. Because retracting the mandibular incisors increases the relative prominence
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of the chin, this can make the facial appearance worse rather than better. Extracting the mandibular first premolars to provide space for a major retraction of the incisors is rarely a good idea; extracting 1 mandibular incisor allows modest retraction and often does not lead to the tooth-size discrepancy that might be expected. The discrepancy decreases and may even disappear with upright mandibular incisors and proclined maxillary incisors. Bone screws in the mandibular ramus can provide enough anchorage to retract the entire mandibular arch, although doing this requires extraction of the third molars and often the second molars as well. For Class II patients, camouflage is just the reverse: retraction of the maxillary incisors and proclination of the mandibular incisors. With skeletal anchorage, it is easy now to retract the maxillary incisors too much. They should not be retracted beyond the point that the upper lip is vertical—a backward slope of the lip is unesthetic. Proclination of the mandibular incisors can be camouflaged with genioplasty as described above (Fig 5), and genioplasty extends the amount of advancement of the mandibular incisors that can be compatible with a normal facial appearance. Presurgical orthodontic treatment
If the incisors are not reasonably well aligned at surgery, it can be difficult to surgically position the jaws as desired because irregular teeth create dental interferences in the new jaw positions. For this reason, alignment is the first step in presurgical treatment— unless the teeth already are reasonably well aligned, as they sometimes are in patients who need jaw surgery. In that case, the presurgical treatment time can be quite short. A key step in planning alignment, of course, is whether arch expansion, extraction, or interproximal stripping should be used to gain enough space. That decision relates directly to how to achieve the next presurgical goal. Establishment of anteroposterior and vertical incisor positions
Often, even if the teeth are well aligned, dental compensation for the jaw discrepancy has led to a dental occlusion in which the teeth fit better than the jaws. In a skeletal Class III malocclusion, the maxillary incisors are likely to be proclined and the mandibular incisors upright, even before any orthodontic treatment. The opposite is seen in skeletal Class II patients, in whom proclination of the mandibular incisors often develops
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during growth. If the dental compensation is not removed before surgery, the jaw correction will be inadequate when the surgeon brings the teeth into occlusion as the jaw is repositioned. The guideline is that the presurgical movement of retruded or proclined incisors should be at least a 100% correction or slightly more if possible, because inevitably there will be some relapse toward the original incisor position. Overeruption of the incisors often partially compensates for the severity of an anterior open bite in longface patients, and intrusion of the incisors is needed to correct this before surgery. In long-face patients who are being prepared for vertical repositioning of the maxilla, it is almost always a serious mistake to elongate the incisors while leveling the dental arches. This would increase an incisor display that is already excessive and build in an unfortunate relapse tendency that can lead to posttreatment bite opening. In short-face deepbite patients, dental compensation is less frequent, and often excessive eruption of the mandibular incisors and accentuation of the curve of Spee occur. Is intrusion of these incisors needed? That depends on the face height desired after surgery, because posttreatment anterior face height is determined by the vertical position of the incisors. When an increase in face height is needed, leveling the mandibular arch mainly by elongating the canines and the premolars often is the best treatment plan. For these patients, it is best to simply align the arch without presurgical leveling and complete the leveling postsurgically when the teeth that need to be extruded are no longer in occlusion. Other presurgical orthodontic treatments
For many patients, the maxillary arch form needs to be made compatible with the mandibular arch form before surgery. Failure to do that leads to canine interferences as the teeth are brought into occlusion at surgery. Arch form compatibility in Class II patients can be estimated by having the patient bite forward, but for Class III patients, dental casts to check compatibility are required. Sometimes, it is easier to understand what needs to be accomplished by considering what is not needed. Intrusion of teeth must be done presurgically, but extrusion often can be done more easily postsurgically. Correction of minor (half cusp) crossbites that would exist after repositioning of the jaws can be done postsurgically; major ones (full cusp) need presurgical correction. Extraction sites should be closed before surgery unless segmental osteotomies will be used to
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Fig 5. Dentofacial changes after functional genioplasty to bring the chin upward and forward: A and B, after extensive orthodontic treatment that resulted in good dental alignment and occlusion but did not control long face growth; C and D, 6 months after surgery. Note that the lower lip moved up along with the chin, allowing lip closure in function and eliminating the display of the mandibular incisors that was not appropriate for a 14-year-old girl.
close them, but root paralleling can be finished postsurgically. The overall goal must be kept in mind: get the presurgical arrangement of the teeth to the point that postsurgical orthodontic treatment will not take more than 6 months—and don't waste a lot of time trying to perfect the occlusion presurgically. Some postsurgical orthodontic treatment will be needed for every patient. Final surgical planning
The orthodontist and the surgeon should communicate on progress toward surgery throughout the presurgical orthodontic phase of treatment. Consensus on the
patient's readiness for surgery should be reached at least 3 months before the surgery date. Hospital schedules depend on insurance approvals, which often must be confirmed by submitting added patient information. In addition, both clinicians should agree on the presurgery tooth alignment and the desired jaw position after surgery. Unfortunately, this communication between the orthodontist and the surgeon often is forgotten or delayed until too close to the surgery date, causing problems that include less-than-optimal outcomes. Inadequate canine or molar expansion that limits the surgeon's ability to position the teeth and the jaws in the ideal position is a frequent problem, created because
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presurgical models were not obtained before sending the patient to the surgeon. Three-dimensional imaging now plays an increasing role in the final surgical planning because software and technical support allow the surgeon to do this without the articulator-mounted casts needed previously for model surgery. The software allows a cranial base registration, from which the surgeon can see planned movements and the interaction between the surgical segments from any perspective. This has 3 advantages: it makes it easy to evaluate several possibilities in positioning the segments without having to do repeated model surgeries; it allows the surgeon to visualize how proximal and distal segments will approximate so that condylar torque can be reduced (which is especially important in patients with asymmetry); and it eliminates the need to make surgical splints with repositioned dental casts. The splints can be formulated accurately from the final positions of the virtual segments as anatomically correct stereolithographic models. If skeletal anchorage would be needed for postsurgical tooth movement, positioning the screws or bone planes also can be part of the surgical plan. The combination of these advantages makes model surgery easier and more efficient, especially for complex cases. Whether this justifies the additional radiation and cost has not yet been clearly established.
A patient having orthognathic surgery is managed by the surgeon and the anesthesiologist from the point that the patient is deemed ready for surgery until he or she is discharged from the surgical facility. Management by the surgeon (which includes elastics to help the patient adapt to the new jaw position) continues until the patient is judged ready to resume active orthodontic treatment.
Mistakes of the past include leaving stabilizing archwires in place after removal of the splint and omitting elastics with the first postsurgical archwires. The goal of the elastics is not to move the teeth—the archwires can do that. We have learned that without guiding elastics, a slide in jaw position from initial contact to an acquired position often develops, and this is difficult to eliminate if it occurs. The working archwires usually consist of a flexible rectangular archwire in one arch (the one in which tooth orientation needs to be maintained, usually the maxillary arch) and a round wire in the other arch (where more tooth movement is needed). For postsurgical orthodontic treatment, monthly appointments seem to be the best choice. More frequent appointments carry with them a risk of damage to the teeth or periodontal structures; longer ones delay the completion of treatment. The goals are to complete the orthodontic treatment and remove the appliances in 4 to 5 months after the surgery. If postsurgical treatment takes longer than 6 months, presurgical preparation was inadequate. Retention for surgical patients is not different from retention generally, with 1 exception: maxillary expansion with segmental surgery is not stable for 6 to 8 months after surgery. We have learned that expansion must be maintained during the postsurgical orthodontic treatment and after the appliances are removed. A suck-down retainer placed immediately after appliance removal seems prudent, rather than waiting until a laboratory can make a wire or an acrylic retainer. This short-term option can be replaced with a retainer with palatal coverage later, but after surgical expansion, full-time retainer wear is needed for up to 8 months postsurgery. Then part-time retainer wear for at least another 4 to 6 months has proven to be beneficial.
Postsurgical orthodontic treatment
Surgery first?
The goal of postsurgical orthodontic treatment is straightforward: bring the teeth into occlusion while correcting minor discrepancies and helping the patient adapt to the new jaw and occlusal relationships. The use of rigid fixation devices to stabilize repositioned facial bones and facilitate healing has assisted the orthodontist, allowing earlier treatment postsurgery without the fear of disturbing the new jaw positions, but the surgeon's judgment should determine when active orthodontic treatment resumes. At that point, flexible working archwires are placed, and the patient should wear light posterior vertical elastics full time until the next appointment.
Recently, it has been suggested that with modern technology and techniques, surgery first once again should be considered, at least for selected patients, with the primary goal to shorten the total treatment time. Without data for treatment outcomes for this approach, it is too early to adopt it over a sequence with known positive outcomes. As noted above, studies of the psychological response to orthognathic surgery have shown that at 6 months postsurgery, patients begin to be increasingly stressed by continued orthodontic treatment. Even with selected patients, postsurgical treatment times with surgery first extend well beyond that time.
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Limitations in magnitude and direction of surgical movements
At this point, the combination of orthodontic treatment and orthognathic surgery allows almost every surgical movement that would be desired, but with limitations in some directions and in the distances of movement. We summarize with the following. 1.
2.
3.
4.
The maxilla can be moved forward about 6 mm before stability becomes a problem. Moving the whole maxilla back is possible, but is quite difficult and unnecessary in any case because the anterior segment can be moved back if protrusion of the incisors is excessive. It can be stably moved up for almost any patient farther than is compatible with acceptable incisor display, and this is the limitation for superior repositioning. Short-term stability is a problem with moving the posterior maxilla down, but rotating it down anteriorly to increase incisor display is not. The mandible can be moved forward or backward, but backward movement is predictably unstable, and with either forward or backward movement, moving the gonial angle down (increasing ramus height and decreasing the mandibular plane angle) is a prescription for relapse into an anterior open bite because of a lack of muscle adaptation. Rotation in the other direction, increasing anterior face height and the mandibular plane angle, is quite stable. Alveolar segments can be moved in any direction and can be expected to be stable if the segment was not too small and good bony contact was maintained; this, of course, imposes limits on the amount of movement. The same guidelines apply to repositioning the chin, discussed above.
A 21ST CENTURY PERSPECTIVE: WHAT DOES THE FUTURE HOLD?
Our ability to predict the future is no more accurate than other knowledgeable clinicians, but current trends do offer probable outcomes for at least the next decade and perhaps longer. Based on U.S. population data in 2010, more than 2 million people ages 15 to 19 years live in our country (U.S. Census Bureau, 2010 data). The 1975 report from a study by the National Academy of Sciences estimated that as many as 5% of American adolescents might have a “handicapping malocclusion,” which we now call a dentofacial deformity.15 If half of those would need orthgnathic surgery, this suggests that at least 500,000 adolescents might require evaluation for orthognathic surgery annually. No obvious
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reason exists for a future decrease in the numbers in this affected target population. We suggest that the following factors at least will influence how affected persons will get evaluation and treatment if needed. Although interrelated, the determining factors will be considered separately: education of providers, clinical sites for treatment, practice patterns of treating clinicians, impact of health insurance on access to care, and shifts in the commitment of the United States to provide care for all or most of the population. Education of providers
Referrals for evaluation of young adults with a dentofacial deformity should arise from primary care physicians and general dentists. Although some efforts are emerging to educate physicians on oral health issues, for the near future we must assume that current physicians as a group will not routinely refer those in need for evaluation, even though the trend with the Affordable Care Act is to require physician referrals for evaluation and possible treatment involving any surgery. In most dental schools, students are exposed to aspects of combined treatment by orthodontists and surgeons in orthognathic surgery. The educational exposure is not uniform. Currently, general dentists, even if knowledgeable, have little incentive to refer affected patients for evaluation of combined surgicalorthodontic treatment, particularly if the unknowing patient or family is unaware of treatment options. A concerted effort by the American Association of Orthodontists and the American Association of Oral and Maxillofacial Surgeons could raise awareness of this issue, but practice patterns that we describe later mitigate that as a priority for either group. In contrast, most orthodontists and surgeons in training and practice have had the opportunity to treat patients with dentofacial deformities; this is clearly different from only a few decades ago and is a positive trend for the future. Clinical sites for treatment
Orthodontic clinical sites in both community practices and academic centers are equipped to provide the needed evaluation and treatment services for persons with dentofacial deformities. Unless the patients are the focus of a community practice of oral and maxillofacial surgery, surgery practices are not equipped for the needed evaluations. This deficit is not insurmountable, assuming that surgeons are willing to collaborate on a regular basis with orthodontists. However, evolving practice patterns in the community offer little promise that the collaborations will routinely or easily occur.
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Orthognathic surgery has become efficient and effective today. Performing the surgery does require both a surgeon trained in and familiar with current techniques and an anesthesiologist familiar with the patient's needs and willing to provide anesthesia services. For the most part today, either a specially equipped ambulatory surgical center with recovery services able to meet the special needs of these patients or an appropriately equipped hospital operating room is required. The volume of patients is important to both entities. Investing in the required instruments and devices is not cost-effective otherwise. This suggests a concentration of orthognathic surgeries in selected clinical sites and an impact on which surgeons perform the surgeries. Practice patterns of treating clinicians
Most orthodontists are adequately trained to offer orthodontic services to patients with dentofacial deformities. Almost all orthodontists will see at least a few affected patients in their community practices. Some find care of these patients rewarding and challenging, perhaps different enough to maintain the clinician's interest. If sufficient interest is widely known, affected patients may tend to concentrate in certain orthodontic practices. Barriers to orthodontists' willingness to treat these patients include the required collaboration for each patient over time with surgeons who may not be geographically near, added liability for less-thandesired outcomes, complicated processes for insurance approvals, and the extra hassle of treating patients who require differing treatment protocols. That said, the rewards of successfully treating patients with dentofacial deformities make it likely that enough orthodontists will be available to care for any projected numbers of patients seeking treatment. The situation for surgeons is quite different. Almost all are trained for orthognathic surgery and capable of treating all but the most difficult patients upon completing residency. At this point, the practice patterns of surgeons diverge. Many if not most surgeons today in community practices do not have a regular schedule for hospital surgery and do not work more than occasionally in the hospital. The reasons are many. If the surgeon has a dedicated ambulatory facility, it must be staffed heavily with salaries supported by the patients treated. Insurance carriers have deduced that low surgery fees discourage surgeons from treating complicated patients. In a short time if few patients are treated, the surgeon has little incentive to continue performing orthognathic surgery. Exceptions exist; a few community practices actively seek patients with dentofacial deformities. Working relationships with certain orthodontists are courted, making
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collaboration easy. Dedicated ambulatory surgery sites are designed, equipped, and staffed to care for patients before and after surgery. The staff are specially trained to assist the surgeons and anesthesiologists. However, we suggest that most orthognathic surgery in the future will be performed in academic medical centers whose hospitals are equipped and staffed for the patients' needs. Under this outcome, surgeons will have the needed volume of patients to be current with methods and meet the requirements to maintain hospital privileges. Impact of health insurance on access to care
A curious and perhaps predictable reaction from insurance carriers has evolved on paying for orthognathic surgery. Orthodontic care continues to be “self-pay” or paid for by a combination of dental insurance and copayments. There is little adjustment or accommodation for the complexity of care. This pattern is likely to continue for orthodontics, and no trend is seen for more patients having some form of dental insurance. At the outset in the 1980s, medical insurance covered orthognathic surgery similar to orthopedic and other surgery. As the numbers of patients treated increased with the advent of effective surgery, insurance carriers saw increasing outlays of their premium dollars. To discourage claims, the carriers first claimed that orthognathic surgery did not meet their definition of “medical necessity.” About the same time, the U.S. Surgeon General and the World Health Organization called attention to quality-of-life outcomes being as important as “medical” outcomes. Clearly, orthognathic surgery patients benefitted from improved quality of life, and the change in quality of life outcomes as the medical criterion made “medical necessity” moot, but some, although fewer, carriers offer this today as a reason to deny claims. The current strategy of insurance carriers is quite effective in limiting outlays for orthognathic surgery. Surgeons are paid at ridiculously low levels and cannot bill patients beyond this level as a requirement of being in the carrier's network. This contributes to having orthognathic surgery concentrated in a few centers. As hospital consolidations continue, which is required for hospitals to be large enough to counter the economic influence of insurance carriers and the pharmaceutical industry, surgical services including orthognathic surgery will be concentrated at fewer sites, with patients treated by surgeons hired specifically for that purpose. Commitment to provide health care for the population
By many measures, health care in the United States is a nonsystem and a failure in comparison with other
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developed countries. For economic reasons alone, things will change. We cannot afford the current trend in expenditures as a nation. Much will depend on political maneuvering and priorities based on economics. Examples abound, including the several states that refused to expand Medicaid services. Where will orthognathic surgery rank in priority compared with other procedures to improve quality of life such as orthopedic surgery for arthroscopy or joint replacement? Advocates for orthognathic surgery will first be the consolidated hospital centers that have effectively concentrated services in selected sites. They have made a commitment to maintain orthognathic surgical services similar to other surgical services, cardiac and orthopedic among them. We cannot predict how strong an advocacy we might expect from the American Dental Association, the American Association of Orthodontists, or the American Association of Oral and Maxillofacial Surgeons. Even if committed, their advocacy has had a mixed outcome in the past. Unfortunately, other health care advocacy groups know little about dentofacial deformities; this certainly is not helped by the division in education for dentists and physicians. Perhaps the most compelling reason for believing that orthognathic services will continue in the future is the number of affected young adults who can benefit from treatment. As we commented at the outset, predicting the future is problematic. However, we hope we have offered “food for thought” as the future comes upon us. REFERENCES 1. Trauner R, Obwegezer H. The surgical correction of mandibular prognathism and retrognathia with consideration of genioplasty. Oral Surg Oral Med Oral Pathol 1957;10:787-92.
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2. Bell WH. LeFort I osteotomy for correction of maxillary deformities. J Oral Surg 1975;33:412-26. 3. Epker BN, Wolford LM. Middle third facial osteotomies: their use in correction of acquired and developmental deformities. J Oral Surg 1975;33:491-514. 4. Proffit WR, White RP Jr. Contemporary treatment of dentofacial deformity. St Louis: Elsevier; 2003. (now available in electronic edition only). 5. Proffit WR, Fields HW Jr, Sarver DM. Contemporary orthodontics. 5th ed. St Louis: Elsevier; 2013. 6. Posnick JC. Orthognathic surgery: Principles and practice. St Louis: Elsevier; 2014. 7. Chamberland S, Proffit WR, Chamberland PE. Functional genioplasty in growing patients. Angle Orthod 2014 [Epub ahead of print]. 8. Chamberland S, Proffit WR. Short-term and long-term stability of surgically assisted rapid palatal expansion revisited. Am J Orthod Dentofacial Orthop 2011;139:815-22. 9. Bailey LJ, Phillips C, Proffit WR. Long-term outcome of surgical Class III correction as a function of age at surgery. Am J Orthod Dentofacial Orthop 2008;133:365-70. 10. Proffit WR, Phillips C, Turvey TA. Long-term stability of adolescent versus adult surgery for treatment of mandibular deficiency. Int J Oral Maxillofac Surg 2010;39:327-32. 11. Scheffler NR, Proffit WR, Phillips C. Outcomes and stability in patients with anterior open bite and long anterior face height treated with temporary anchorage devices and a maxillary intrusion splint. Am J Orthod Dentofacial Orthop 2014;146:594-602. 12. Kiyak HA, McNeill RW, West RA, Hohl T, Bucher F, Sherrick P. Predicting psychologic responses to orthognathic surgery. J Oral Maxillofac Surg 1980;40:150-5. 13. Phillips C, Hill BJ, Cannac C. The influence of video imaging on patients’ perceptions and expectations. Angle Orthod 1995;65: 263-70. 14. Jackson TH, Mitroff SR, Clark K, Proffit WR, Lee JY, Nguyen TT. Face symmetry assessment abilities: clinical implications for diagnosing asymmetry. Am J Orthod Dentofacial Orthop 2013;144: 663-71. 15. Morris AL, et al. Handicapping orthodontic conditions. Washington DC: National Academy of Sciences; 1975.
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