J Oral Maxillofac Surg 5037-94. 1992

Facial Width Problems Associated With Rigid Fixation of Mandibular Fractures: Case Reports EDWARD

ELLIS

III, DDS, MS,* AND WICHIT

Report of Cases Case 1 A 33-year-old man sustained a right subcondylar and left symphysis fracture in an altercation. He had a very poor dentition, with only a few remaining teeth. He was taken to the operating room where an open reduction of his left symphysis fracture was secured with a 2.7-mm reconstruction bone plate. The condylar fracture was not addressed surgically. He did well and was discharged on the first postoperative day. Several weeks later, the patient complained of facial asymmetry and a draining sinus tract in the submental area adjacent to the bone plate. Examination of the patient showed that the right side of his face was much broader than the left (Fig 1A). Palpation of the area showed a laterally displaced mandibular ramus. The patient had a good range of man-

Case 2 A 29-year-old man sustained multiple facial fractures in a motor vehicle accident 3 days prior to being transferred to Parkland Memorial Hospital. On admission, his condition was stable and no additional injuries were found. His facial fractures included a grossly mobile Le Fort I maxillary fracture with a midline split, bilateral zygomatic complex fractures, bilateral mandibular condylar fractures, and a fracture of the mandibular symphysis. He had lost the maxillary central incisors during the accident. He was taken to the operating room, where maxillary and mandibular arch bars were attached to the remaining dentition. The mandibular condylar fractures were treated with open reduction and internal fixation using six-hole 2-mm bone plates. Following exposure of the mandibular symphysis fracture, which was oblique, the maxillary and mandibular segments were placed into MMF. With a proper occlusal relationship restored by MMF, lag screws were inserted into the symphysis fracture to stabilize it, providing rigid fixation (Fig 2A). The zygomatic complex fractures were reduced next and internally stabilized. Lastly, the Le Fort I maxillary fracture was reduced and stabilized

Department of Oral and MaxillofacialSurgery,University of Texas Southwestern Medical Center, Dallas, TX. * Associate Professor. t Resident. Address correspondence and reprint requests to Dr Ellis: Division of Oral and Maxillofacial Surgery, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 752359031. Association

of Oral and Maxiltofacial

DDSt

dibular motion. but very little translation of the right mandibular condyle. A very slight amount of purulence could be expressed from the submental wound. Radiographs showed lateral displacement of the mandibular ramus secondary to inadequate contouring of the symphyseal bone plate (Fig 1B). The patient was taken to surgery, where removal of the bone plate in the symphysis was performed through a transoral approach. There was a minimal amount of purulence in the wound; the fracture was firmly healed. External pins were inserted into the mandibular rami for fixation and for measuring the amount of surgical change produced in narrowing the mandibular arch (Fig 1C). It was necessary to perform an ostectomy in the symphysis, with more bone removal at the inferior border and on the lingual than superiorly and buccally, to facilitate medial rotation of the right ramus. It was thought that a vertical ramus osteotomy might be necessary on the right side to facilitate this movement. but the ramus rotated medially very easily after the symphyseal osteotomy was performed. Postsurgically the patient did very well and no further drainage from the symphyseal wound occurred. The external pins were removed on the sixth postoperative week. The patient was very satisfied with the result; however, there was still a slight amount of preauricular fullness on the right side secondary to a loss of ramus height from the condylar fracture (Fig ID).

In recent years. surgeons increasingly have been using rigid internal devices to treat many maxillofacial fractures. The use of rigid forms of internal fixation, however, can be a two-edged sword. When properly used, such devices can be of great benefit in that they can maintain the position of the reduced bony fragments, and do so without the need for maxillomandibular fixation (MMF). However, when improperly applied, such devices can induce problems. One such problem, which is easy to create using rigid internal fixation, is an increase in the width of the face. The purpose of this article is to present two cases of increase in facial width following surgical correction of mandibular fractures using internal fixation devices and to discuss the mechanism, prevention, and correction of such complications.

0 1992 American

THARANON,

Surgeons

027%2391/92/5001-0021$3.00/O

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FIGURE 1. A, Appearance of patient several weeks after bone plate stabilization of symphyseal fracture. The right condylar fracture was not treated. Note widened appearance of face due to lateral displacement of right mandibular ramus and shortening of right posterior facial height. B. Posteroanterior cephalogram showing widened appearance of mandible. Lines indicate surgical treatment objective. C’, Intraoperative photograph showing use of goniometer between external pins to determine the amount of narrowing accomplished at surgery. D. Appearance of patient several weeks after narrowing of mandibular ramus.

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FIGURE 2. .1, lntraoperative photograph of symphyseal fracture stabilized with lag screws. B. Appearance of patient 14 days following surgery. Note severe widening of the face. (: Occlusal radiograph showing poor reduction of mandibular symphyseal fracture. This inappropriate reduction caused widening of the mandibular rami. D, Occlusal radiograph of symphyseal fracture after removal of lag screws and narrowing of mandible. A large bone plate was used to stabilize fracture. E. Appearance of patient I year after surgery.

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with bone piates to the repositioned

zygomatic

complexes. No postsurgical MMF was used. The patient underwent a normal postoperative course and was discharged on the second postsurgical day. Radiographs taken prior to discharge showed a good result. One week later, the patient was seen and found to be healing well. On the second postoperative week, the patient still appeared to have “swelling” of the cheeks and lateral aspect of the face (Fig 2B). However, palpation revealed that the fullness was firm to the touch and was thought to be displacement of the mandibular rami laterally. An occlusal radiograph of the symphysis fracture was obtained that showed a poor reduction of the symphyseal fracture (Fig 2C), causing widening of the mandibular, and therefore, maxillary arch form. In spite of the fact that the occlusal relationship appeared perfect, it was thought that the most appropriate course to follow would be to take the patient back to the operating room where the symphysis fracture and maxillary fractures could be more adequately reduced and secured. On the 15th postoperative day. the patient was returned to surgery. The lag screws in the symphysis and the bone plates at the Le Fort I level were removed. Maxillomandibular fixation was reapplied. Using digital pressure at the gonial angles, the symphyseal fracture was approximated more appropriately. An eight-hole bone plate was secured around the circumference of the symphysis to maintain this morphology (Fig 2D). The internal fixation of the maxillary fracture was then adjusted to accommodate for the decrease in arch form. Postsurgically, the patient had a more normal appearance and was discharged on the first postoperative day (Fig 2E). He continued to do well and the arch bars were removed 3 weeks following the second surgery.

Discussion The two cases presented illustrate the problems that can occur without proper attention to detail when using

FIGURE 3. Illustration showing how the pull of the suprahyoid musculature causes the symphysis to move posteriorly and the mandibular rami to move laterally when a symphyseal fracture is associated with condylar fractures.

rigid internal fixation devices in the treatment of patients with mandibular fractures. It is probable that more cases of facial widening have occurred since the use of rigid internal fixation devices because it is very easy to induce this deformity using such devices. This is especially true in the area of the mandibular symphysis, where a small error in reduction can result in a large change in the position of the mandibular rami. One must be fully cognizant of the nature of the injuries being treated and the appropriate use of the armamentarium available to them to help avoid such iatrogenic deformities. The following sections discuss the mechanism by which an increase in facial width can occur, the most appropriate methods to try and prevent the

FIGURE 4. Illustration showing flaring of the gonial angles (4) with a symphyseal fracture caused by tightening of the maxillomandibular wires (B).

ELLIS AND THARANON

occurrence, and, briefly, the correction of iatrogenically induced increases in facial width.

MECHANISM

Many combinations of fractures have a natural tendency to cause a widening of the face by lateral displacement of the mandibular rami. When support for the mandibular symphysis is lost due to fractures of the mandibular condyle, angle, body and/or symphysis, there is a tendency for the symphyseal region to move posteriorly and the rami to flare laterally. The main cause of these movements is pull of the lingual musculature attached to the mandibular symphysis (Fig 3). There are two groups of facial fractures, in particular, that have potential to increase or widen the face postsurgically: isolated mandibular fractures and combinations of maxillary segmental and mandibular fractures. However, with proper reduction and fixation techniques, this tendency can be obviated. Isolated mandibular fractures that are prone to increase facial width are symphyseal fractures, especially those with associated condylar fracture(s) and a poor dentition. In most cases, a good interdigitating dentition allows for the proper reestablishment of mandibular form. However, even with an intact dentition, there is a tendency toward splaying of the gonial angles due to the application of the maxillomandibular wires on the buccal surface of the dentition (Fig 4). Tightening the wires around the arch bars can cause the mandibular segments to tip lingually, even though the teeth appear properly interdigitated. In those symphyseal fractures treated by an open procedure, a gap in the line of fracture may be noted at the inferior border of the mandible even though the mandibular incisors are in approximation superiorly. It may be necessary to loosen the wires slightly to obtain proper osseous reduction at the inferior border in such cases. This tendency toward widening at the gonial angle is much greater when the dentition is poor or absent. In such cases, mandibular arch form is very difficult to assess and a great amount of widening at the gonial angles can occur if the bones themselves are not inspected for approximation. Associated fractures of the condyle(s) compound the difficulty. because there is no longer any posterior stability provided by the temporomandibular articulation. In such instances, there is a tendency not just for the gonial angles to move laterally, which is a tipping of the ramus around the TMJ, but the entire ramus can move laterally. Multiple mandibular fractures associated with segmental maxillary fractures constitute a unique set of circumstances that are prone to the complication of widening of the face. When there is no intact maxillary

91 arch to serve as a blueprint for reestablishment of mandibular arch form, the surgeon is faced with a difficult problem. One must understand that the arch forms established during surgery will directly affect the width of the mandibular rami. If improperly reestablished, the rami will be wider than their preoperative position. Internal fixation with a bone plate at the mandibular symphysis may lead to a perpetuation of widening of the gonial angles and rami. If the bone plate is not properly bent and/or overbent, the lingual cortices may not contact even though the buccal cortices appear perfectly reduced (Fig 5). In such instances, tightening of the screws, especially if compression is applied, will cause the rami to move laterally. Another, more rare form of widening of the face, occurs with loss of posterior mandibular vertical dimension following fracture of the mandibular condyle(s). In this instance, the deformity is owing to a bunching of facial soft tissues and, fortunately, is not usually as disfiguring as when the ramus is displaced laterally.

FIGURE 5. Illustration showing how inappropriate contouring of a symphyseal bone plate can cause a widening of the mandibular arch (note gap of lingual cortex). When condylar fractures are also present, the condyles may remain in their fossae (A). If no condylar fractures are present, the entire ramus, including the condyles, is laterally displaced.

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PREVENTION

One should understand that the complication of facial widening is totally preventable. In fact, if the facial width is noticeably greater than normal for that individual in the postsurgical period once the edema has subsided, one can be assured that the surgeon, although perhaps not creating the problem, did not correct it. The use of internal fixation devices in the injuries previously discussed will very easily create this complication if used inappropriately, and can very easily prevent it when properly applied. A few points should be made concerning the treatment of such injuries. Isolated mandibular fractures. Following application of arch bars, the mandibular arch form should be assessed to determine if there is a tendency for widening of the gonial angles. This is most easily performed by examining the interdigitation of the dentition while applying digital pressure at the gonial angles. If the mandibular teeth are lingually inclined and upright to a more normal relationship with digital pressure at the gonial angles, one should consider open reduction of the symphyseal fracture. When the fracture has been exposed to determine the appropriateness of the reduction or to apply fixation devices, a gap in the line of fracture at the inferior border may be noted even though the teeth on either side of the fracture are in contact superiorly. If digital pressure at the gonial angles will eliminate the gap (it may be necessary to first

slightly loosen the maxillomandibular wires), it should be eliminated by proper reduction and internal fixation. If MMF is going to be used as the means of postsurgical immobilization, a wire is satisfactory, but is most effective if placed bicortically so that the lingual cortices are also approximated by the wire. If one is going to apply a bone plate, a towel clamp or bone clamp applied to the buccal surface of the bone serves to reduce the fracture well; however, if there are associated fmctures of the mandibular condyle(s) or angles, one must dissect beneath the inferior border to visually assess that the lingual cortices are in intimate contact. Frequently, a perfect reduction of the buccal cortex can occur in the face of a I- to 2-mm gap of the lingual cortex. Another useful maneuver is to inspect the buccal cortex while applying pressure at the gonial angles (Fig 6). At the point when the buccal cortex begins to separate following application of digital pressure at the gonial angles, one can be assured that the lingual cortices are in contact and are the point of fulcrum around which the buccal cortex is beginning to separate. It is at this point that the internal fixation device should be adapted. If a bone plate is used, one should first bend the plate to the exact contour of the properly reduced bone and then overbend the plate so that it is 1 to 2 mm off the bone in the area of the fracture (Fig 7). Overbending the bone plate allows it to apply compression to the lingual cortex and prevent the tendency for a gap to arise when it is applied to the buccal

FIGURE 6. Illustration showing a method to help assure proper approximation of the Iingual symphyseal cortices. The mandibular rami are pressed medially while observing the buccal cortex of the symphyseal fracture (A). One should press until the buccal cortices begin to separate, indicating that the lingual corks are in contact and are the fulcrum for the separation of the buccal cortices (B). When the buccal cortices are at the point of beginning separation, the fracture is well reduced (C).

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arch. In this instance, the mandibular fractures must be opened and rigidly stabilized to assure that proper osseous reduction has occurred, which in turn assures that proper arch form and mandibular width have been achieved. The maxillary arch configuration can then be restored by placing the dento-osseous segments into MMF with the mandibular dentition. Loss of posterior mandibular vertical dimension. One must strive to maintain the posterior vertical dimension of the mandibular angle following fractures of the mandibular condyle to prevent this complication. This is usually a simple task if open reduction of the fracture has been undertaken, or if a dentulous patient is treated with closed reduction. However, it is very difficult to prevent in edentulous patients who are treated without open reduction, as even the wearing of splints or dentures allows superior repositioning of the gonial angle because of lack of adequate posterior sup port of the mandible from the prostheses. CORRECTIONOF FACIAL WIDENING

FIGURE7. Illustration showing proper application of a symphyseal bone plate (A). The plate should be bent to the exact contour of a properly-reduced symphysis (B), and then overbent so that the plate is 1 to 2 mm off of the bone in the area of the fracture (C). When the bony segments are then drawn to the plate by bone screws, approximation of the lingual cortex is assured (D).

cortex. One must understand that even a small gap of the lingual cortex in the area of the symphysis will lead to a much greater increase in the width of the gonial angles. Combination of segmental maxillary fractures and multiple mandibular fractures. When no existing template for proper arch form is available because of disruption of the integrity of both dental arches, it is imperative that one arch be rigidly reestablished to serve as the blueprint for the other. The only way to assure proper width of the mandibular rami is to reestablish the proper dental arch width. Whether this is done with interdental splints, rigid internal fixation devices, or external pin fixation is irrelevant as long as the proper mandibular width is reestablished. When the maxilla has been fractured into two fragments, frequently halves, the maxillary arch can very easily be reestablished by using acrylic splints and/or small bone plates across the palate. I4 Once the maxillary arch is reestablished, the mandibular arch can be reestablished by placing the patient into MMF. On the other hand, if the maxillary arch is in multiple segments, it may be much easier to restore the continuity of the mandibular arch and use it as a template for the maxillary

The most effective method by which iatrogenic widening of the face can be corrected is to return to surgery as soon as it is diagnosed for repositioning of the bony segments. There is always the temptation to take awaitand-see approach to such patients as they usually have been through an enormous amount of surgery already for the facial and possibly concomitant injuries. However, improvement cannot be expected to occur spontaneously and, if anything, further widening may occur due to pull of the soft tissues. One must identify the nature of the problem and surgically correct it. If a patient had only mandibular fractures, identification of the problem is easier than when a combination of maxillary and mandibular fractures exists. If the maxillary arch form was not disrupted, yet the mandibular rami appear wide, it must be owing to 1) establishment of an improper occlusion, ie, a posterior crossbite and/or 2) lingual tipping of the mandibular dentition with concomitant separation of the inferior portion of the mandibular symphysis fracture. The teeth need not be in total crossbite to have widening of the mandibular rami; the mandibular buccal cusps may be occluding along the lingual inclinations of the maxillary buccal cusps. This situation, in concert with lingual tipping of the mandibular teeth, can widen the rami much more than it would appear possible by looking at the dentition. In the patient who has sustained segmental maxillary and mandibular fractures, treatment is not as easy because the increased width is usually present in both jaws. In the dentulous patient with what appears to be a proper occlusal relationship following such fractures,

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it will usually be that an improper arch form was established at the time of surgery. The proper arch form must be reestablished. This will usually mean treating both the maxilla and mandible. If one has a patient who has a posterior crossbite, it is probable that the maxillary arch form was properly established but the mandibular arch form is too wide. Correction in this instance should be accomplished in the mandible as previously described. If sufficient time has elapsed, and the fractures have healed, one must perform the necessary osteotomies to recreate the fractures. Most commonly, mandibular ramus osteotomies must also be performed to allow

the mandibular condyles to remain in whatever position they are now functioning. References 1. Quinn JH: Open reduction and internal fixation of vertical maxillary fractures. J Oral Surg 26:167. 1968 2. Davis. DC, Constant E: Transverse palatal wire for the treatment of vertical maxillary fractures. Plast Reconstr Surg 48: 191,

1971 3. Manson PN, Shack RB, Leonard LG, et al: Sagittal fracture of the maxilla and palate. Plast Reconstr Surg 72:484, 1990 4. Manson PN. Classman D, VanderkolkC, et al: Rigid stabilization of sagittal fractures of the maxilla and palate. Plast Reconstr Surg 85:71 I, 1990

J Oral Maxillofac Surg 50:94. 1992

Discussion Facial Width Problems Associated With Rigid Fixation of Mandibular Fractures: Case Reports Brian Alpert, DDS University of Louisville, Louisville. KY

The authors bring to our attention a not uncommon, but seldom described, complication of severe mandibular fractures. Splaying of the mandibular angles with lingual tipping ofthe posterior mandibular dentition is often associated with complex and/or inadequately treated symphyseal fractures. Facial widening also occurs in extreme cases. These particular deformities of facial form and function are being recognized more frequently owing to both the use of rigid fixation and the higher standard of care most expect today. The rigid fixation techniques presently in vogue possess the potential of both exactly reducing and securely fixing these fractures. However, when improperly done, as the authors point out, rigid fixation may perpetuate or even create this deformity. Because rigid fixation methods are so unforgiving, there must be precise attention to detail in insuring that the flaring or splaying of the angles is corrected and/or not created by improper bending of the plate. The authors not only present ways to avoid this complication. but also how to treat it. They appropriately stress that recognition of the deformity and prompt treatment or re-treatment is indicated, as such conditions are not self-correcting. The condition ordinarily should not be difficult to recognize or treat. Following placement of maxillomandibular fixation. careful analysis of the occlusion with respect to lingua1 tipping and/or crossbite of the molar teeth generally reveals this tendency. In those cases also involving maxillary fractures with palatal splits, however, the condition may not be evident when the occlusion is examined. In such cases, surgical access

to the medial cortical plates is indicated to both recognize and treat these potential deformities. More than 20 years ago Walker’ pointed out the necessity for such access, as well as the maneuver of manually compressing the angles in the process of performing open reduction and internal fixation. This is particularly important in the presence of bilateral condylar fractures in conjunction with a fracture of the symphysis. This need for medial access has traditionally been an indication for the extraoral approach. It has likewise been a contraindication for outer cortical plate wiring ofthese fractures, which has been associated with inadequate intraoral degloving approaches where the medial cortices are not visualized. Traditionally, these injuries of the mandibular symphysis have called for devices such as lingual splints to supplement closed and/or open reduction of the fracture.’ Other methods of managing this type of injury have included K-wire fixation of the inferior border in the body region,3 a technique particularly useful when the symphyseal fractures are comminuted. Skeletal pin fixation has also been used effectively. It should be noted that what was once considered an acceptable outcome with traditional techniques is now considered a complication in light of the improved diagnostic and therapeutic means at our disposal. Review of our past results in this as well as other areas confirms this opinion.

References 1. Walker RV: Major oral surgery. C.E. course sponsored by The Catholic Medical Center,- Queens, NY, 1968 2. Clark WD. Bailev B: Management of fractures of the mandible. in Mathog RI? (ed): Maiillofacial Trauma. Baltimore, MD, Williams & Wilkins, 1984, p 155 3. Alpert B: Complications in mandibular fracture treatment, in Manson P (ed): Cranio-Maxillofacial Trauma. Problems in Plastic and Reconstructive Surgery, vol 1, no 2. Philadelphia, PA, Lippincott. September 199 I

Facial width problems associated with rigid fixation of mandibular fractures: case reports.

J Oral Maxillofac Surg 5037-94. 1992 Facial Width Problems Associated With Rigid Fixation of Mandibular Fractures: Case Reports EDWARD ELLIS III, D...
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