CLINICAL STUDY
Maxillomandibular Distraction Osteogenesis Akinwale A. Efunkoya, BDS, FMCDS,*† Babatunde O. Bamgbose, DDS, MS,†‡ Rafael A. Adebola, BDS, FDSRCPSG FWACS,†§ Joshua B. Adeoye, MBChD,§|| and Izegboya O. Akpasa, BDS#
Background: Distraction osteogenesis (DO) is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction. It consists of 4 primary phases, namely, corticotomy and device placement, a latency period, active distraction, and consolidation. The objectives of the current study were to review DO as it applies to maxillomandibular defects and to share our clinical experience in the cases we have done. Methods: A clinical narrative review of the literature was performed to evaluate the use and efficacy of maxillomandibular osteogenesis in maxillomandibular defects. A systematic search of the literature was performed using PubMed, with special interest in the history of DO and its application in dentistry and maxillofacial surgery. medical subject headings terms included surgical procedures, osteogenesis, distraction, and orthodontics. Two cases of maxillomandibular DO managed at the Aminu Kano Teaching Hospital (AKTH), Nigeria, were reported and discussed. Results: Articles involving maxillary and midface distractions, bilateral distraction for airway obstruction, and distraction for hemifacial microstomia were all reviewed. In the first case reported, a unidirectional distractor was used to achieve simultaneous mandibular lengthening and maxillary occlusal correction. Gains of 10 mm in mandibular ramal height and 23 mm in corpus length were achieved in the second reported case, using a bidirectional distractor. The literature search revealed no previous Nigerian reports of maxillomandibular DO. Conclusions: The DO is a viable and available treatment option for reconstructing maxillomandibular discrepancies and accompanying soft and hard tissue deficiencies. Key Words: Distraction osteogenesis, Pierre Robin sequence, corticotomy, case report (J Craniofac Surg 2014;25: 1787–1792)
From the *Department of Restorative Dentistry, Faculty of Dentistry, Bayero University; †Department of Oral and Maxillofacial Surgery, Aminu Kano Teaching Hospital; Departments of ‡Oral Diagnostic Sciences and §Preventive Dentistry, Faculty of Dentistry, Bayero University; and Departments of ||Public Dental Health and #Child Dental Health, Aminu Kano Teaching Hospital, Kano, Nigeria. Received January 13, 2014. Accepted for publication February 10, 2014. Address correspondence and reprint requests to Akinwale A. Efunkoya, BDS, FMCDS, Faculty of Dentistry, Bayero University, Kano, Nigeria; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000907
BACKGROUND Distraction osteogenesis (DO) is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction.1 It has also been defined as a technique for gradual lengthening of bone by application of a gradual external force over a corticotomized site. The corticotomy preserves the neurovascular bundle, whereas the controlled, progressive, and gradual movements create tension in the surrounding soft tissues, initiating a sequence of adaptive changes termed distraction histiogenesis.1 Active histiogenesis occurs in different tissues, including the gingiva, blood vessels, ligaments, cartilage, muscles, and nerves.2–4 The DO is becoming the treatment of choice in the maxillofacial region, including for midface advancement and for mandibular or alveolar ridge lengthening. It is playing a rapidly expanding role in the treatment of children with airway obstruction associated with bilateral microstomia and Pierre Robin sequence. The DO is less invasive and has a significantly decreased morbidity rate compared with the traditional methods of osseous reconstruction. It also provides the added advantage of expanding the overlying soft tissue.5 Orthodontic appliances can correct resultant postdistraction occlusal changes. After Snyder et al6 introduced the concept of DO7–9 to the craniofacial region, many successful craniofacial distraction procedures have been performed on a multitude of patients worldwide.10–13 The DO consists of 4 primary and consistent phases, namely, device placement and corticotomy; a latency period of primary healing; active distraction (at a rate of 1 mm per day until the desired level of distraction is achieved); and after completion of distraction, an additional period of 4 to 6 weeks during which the devices are left in place to allow the regenerated bone consolidate.14 Aldegheri et al15 classified DO techniques into callotasis and physeal distraction. Callotasis is a gradual stretching of the reparative callus forming around bone segments. The ideal rate of distraction for callotasis is 1 mm/d. Physeal distraction is the distraction of bone growth plates and is divided into epiphysiolysis, which is the loosening or separation, either partial or complete, of the growth plate from the shaft of a bone, with subsequent distraction; and chondrodiastasis, which is a distraction of the growth plate without fracture of the plate. Currently, callotasis is the predominant method used for DO.15 The objectives of the current study were to review DO as it applies to maxillomandibular defects and to share our clinical experience in cases we have done.
METHODS A clinical narrative review of the literature was performed to evaluate the use and efficacy of maxillomandibular osteogenesis in conditions affecting the midface and the mandible. A systematic search of the literature was performed using PubMed, with special interest in the history of DO and its application in dentistry and maxillofacial surgery.
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FIGURE 1. Frontal view of patient, showing preoperative maxillary inclination.
Medical subject headings terms included surgical procedures, osteogenesis, and distraction. Two cases of maxillomandibular DO managed at the AKTH, Nigeria, were also reported and discussed.
Bilateral Distraction for Airway Obstruction Pediatric patients with micrognathia or retrognathia, sleep apnea, and severe respiratory obstruction, most commonly associated with Pierre Robin sequence, Treacher Collins syndrome, Nager syndrome, and velocardiofacial syndrome, benefit greatly from mandibular DO.16 It has led to early decannulation in tracheotomized patients. Sesenna et al17 applied mandibular DO in 10 neonatal patients who all underwent fibroscopic examination of the upper respiratory system to confirm that the obstruction was caused by posterior tongue displacement. Indications for surgery were repeated apneic episodes with severe desaturation, and the patients were treated by mandibular DO when other nonsurgical treatments failed to avoid tracheostomy. The study reported improvement in symptoms and signs of airway obstruction, and tracheostomy, when present, was removed. They reported no injury to the inferior alveolar nerve, and scarring was significant in only 2 patients treated with external devices. The anatomic abnormalities in airway obstruction include retroposition of the mandible and reduced effectiveness of the genioglossus muscle in exerting anterior traction on the tongue.18 Success in improving airways with mandibular distraction is linked to anterior displacement of the tongue with increase in mandibular projection. This is due to the intimate relationship of the genial muscles with the anterior mandible.
TABLE 1. Preoperative Soft Tissue Measurements for Patient 1 Right, mm
Left, mm
Maxilla Lateral canthus of 70 60 eye to commissure of mouth Mandible Tragus to angle 55 35 Others Angle-to-facial 90 80 midline Maxillary occlusal 16 degrees (inclined canting downwards toward the right) Midline shift of 15 mandible to the left Derivatives Deficiency in maxillary vertical height = 10 mm (70–60 mm) Deficiency in mandibular ramus height = 20 mm (55–35 mm) Deficiency in mandibular corpus length = 10 mm (90–80 mm)
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FIGURE 2. Reformatted computerized tomographic scan of patient.
Mandibular Distraction for Hemifacial Microstomia McCarthy et al10 were the first to use miniaturized orthopedic distraction devices for mandibular lengthening. Molina and OritzMonasterio19 simplified the methods established by McCarthy et al by using corticotomy instead of osteotomy. Only 1 fixation pin was inserted on either side of the corticotomy and secured to the distraction device. They were the first to use bidirectional osteodistraction in the mandible. The introduction of extraoral bidirectional distraction devices significantly improved the adaptability of DO in cases of mandibular deficiency.20 After these bidirectional devices, several multidirectional devices have been made. A multidirectional distraction device consists of 2 distractor rods with gradually sliding clamps connected in the middle by a universal hinge. This allows linear or angular correction in the sagittal plane and angular correction in the transverse plane. The trajectory of transport bone segment movement may also be changed during the distraction.21 The advantages22 of extraoral distraction include its application for very small children, simplicity of attachment, ease of manipulation, and bidirectional and multidirectional distractions. The external distractors have the disadvantage of creating a difficult psychosocial challenge for children and adults already dealing with the stigma of a facial deformity. There is also the potential for permanent facial scars. The initial development of intraoral mandibular distraction devices began with the miniaturization of the external devices and the modification of available orthodontic expansion devices.23 Guerrero24 developed a midsymphyseal mandibular widening technique using an intraoral tooth-borne Hyrax-type device, treating 11 patients in his first report with transverse deficiencies ranging from 4 to 7 mm. The multiaxis intraoral distractor is, however, the only true three-dimensional intraoral distractor available.25,26 Molina5 reported a 17-year clinical experience with mandibular distraction to achieve simultaneous skeletal and soft tissue correction. The report includes predominant cases of hemifacial microstomia with clinical features covering facial asymmetry, microtia, deviation of the chin to the affected side, hypoplasia of the soft tissue, and associated disorders of other anatomic structures
FIGURE 3. Facial profile at consolidation phase of treatment.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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DO in a Nigerian Teaching Hospital
TABLE 2. Postoperative Soft Tissue Measurements for Patient 1 Right, mm
Left, mm
72
75
55
70
90
80
Maxilla
FIGURE 4. Frontal view of patient at completion of treatment showing improvement in maxillary inclination.
such as the maxilla, zygoma, and muscles of mastication. Although Molina5 did not mention the number of patients treated during the 17-year period, the clinical series included a group of patients with grade IIB hypoplasia, aged between 18 months and 3 years. Lauritzen et al27 classified hemifacial microstomia as hypoplasia affecting the gonial angle (grade I), the angle and ascending ramus (grades IIA and IIB), and complete absence of ramus and the condyle (grade III). The corticotomy and position of the pins determine the distraction vector and differ in each patient according to the grade of mandibular hypoplasia. The parents did lengthening during the night without disturbing the patient’s sleep. After overcorrection, the use of orthodontic appliances and bite blocks corrected the occlusal changes and the vertical dimension of the maxilla. They reported no permanent dental or neurovascular complications, and the consolidation period was 8 weeks or more, depending on the age of the patient. The authors noted that simultaneous soft tissue expansion is the most important factor in obtaining correction of facial asymmetry.
Maxillary and Midface Distraction Maxillary DO was studied experimentally before it was applied clinically to humans. Rachmiel et al28 first reported its possibility, and Block et al29 in 1995 demonstrated anterior maxillary advancement using tooth-borne distraction devices in dogs. Rachmiel et al30 then reported the multiple segmental distraction of the facial skeleton in 3 young adult sheep with obvious new bone formation clinically, radiographically, and histologically. The results suggested that multiple segmental distractions might provide improved three-dimensional control of complex facial deformities. Polley et al31 were among the first to use midface distraction clinically, using an externally fixed cranial halo to distract the midface. The rigid external distractor is an example of such device.32 Its advantages include ease of intraoral application, ease of activation by the patient, and capacity for removal without the need for a second operation at the completion of consolidation. Chin and Toth33 reported on patients who underwent Le Fort III midface advancements with gradual distraction using intraoral devices. Their protocol was different from the traditional IIizarov protocol (tension-stress effect and influence on blood supply) with no latency period. Distraction was initiated intraoperatively and
FIGURE 5. Postoperative radiograph of patient.
Lateral canthus of eye to commissure of mouth Mandible Tragus to angle Others Angle-to-facial midline
often completed in the early postoperative period. The devices could be left in situ, and the authors discovered that long-term stability was good. Molina34 further introduced a technique for simultaneous mandibular and maxillary distraction using only mandibular devices. The technique involved an incomplete Le Fort I osteotomy and a mandibular corticotomy. After a 5-day latency period, intermaxillary fixation was applied, and mandibular distraction was initiated. As the mandible was elongated, the maxilla was moved with it.
CLINICAL REPORT We present our experience with DO at the AKTH, Kano. To the best of our knowledge, these are the first cases of DO reported in Nigeria. The first is an 18-year-old woman who presented with a complaint of “I don't like my facial appearance.” There was a history of left preauricular swelling and pus discharge at 9 months old with progressive deviation of her face to the left side, as she grew older. On examination, obvious facial asymmetry was observed. The left pinna was deformed, and the patient was noted to have a left-sided facial palsy. The mandible was deviated to the left side, the midline was also deviated to the left, and the left ramal height was shortened. The left hemimaxilla was hypoplastic when compared with the right causing a superior inclination of the maxillary occlusal plane on the left (Fig. 1). In profile, the chin was retrognathic. The patient’s mouth opening was, however, adequate. An assessment of the left hemifacial microstomia secondary to condylar hypoplasia was made, and the patient planned for a bimaxillary DO. Preoperative soft tissue measurements were done to estimate the amount of movement required, as outlined in Table 1. With these measurements in mind, planned regenerated (new bone formed by distraction) lengths were 30-mm forward mandibular corpus distraction and 20-mm downward vertical distraction for both the maxilla and the mandible. A vector distance of 36 mm was calculated at 30 degrees at the mandibular angle to achieve these goals.
FIGURE 6. Preoperative pictures of patient (frontal and right profile views, respectively).
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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FIGURE 7. Preoperative picture of patient (left profile and mouth-open views, respectively).
FIGURE 8. Two days postoperative (frontal and right profile views, respectively).
A computerized tomographic scan (Fig. 2) was done for better assessment of the skeletal deformities. The patient underwent the following: maxillary Le Fort I osteotomy, left mandibular angle corticotomy with insertion of an extraoral unidirectional mandibular distractor, and maxillomandibular fixation (MMF) using eyelets and tie wires. A latency period of 7 days was observed, after which the device was activated at a rate of 1 mm per day with a 12-hour rhythm (0.5 mm). The distraction phase was continued for 36 days (35.5-mm movement on device), and consolidation was done for a further 70 days (Figs. 3–5).
Surgical Outcome for Patient 2 At completion of treatment, the patient had gained 10 mm in ramus height and 23 mm in body length. Postoperative jaw dimensions at the end of retention period were shown in Table 4. The patients’ postoperative appearance was satisfactory at the completion of treatment (Fig. 11), and the postconsolidation phase was uneventful. He was placed on regular reviews up to 1 year postoperatively (Fig. 12) and is being planned for further right hemimandibular distraction at ages 16 and 21 years in anticipation of continued left hemimandibular growth.
DISCUSSION
Surgical Outcome for Patient 1 Correction of the maxillary occlusal canting was achieved at the completion of treatment by a combination of maxillary downward distraction and mandibular forward distraction using Le Fort I and angular corticotomies, respectively. At completion of distraction, there was a visibly improved facial profile with postoperative measurements outlined in Table 2. The maxillary occlusal canting had reduced to 5 degrees. The second patient was a 12-year-old boy who presented with a complaint of unequal growth of the lower jaw for 7-year duration. His parents, both nurses, noticed the inequality in growth at approximately 5 years, with the deficiency on the right side. There was history of previous trauma (fall from the bed at 2 years old). There was no limitation of mouth opening, difficulty with chewing, airway obstruction, or associated speech problems. On examination, the patient was found to have a shorter, smaller right hemimandible with midline deviation to the right (Figs. 6, 7), with obtained measurements presented in Table 3. A diagnosis of the right unilateral mandibular hypoplasia secondary to trauma was made. The patient was planned for DO to increase ramus height and mandibular corpus length. A bidirectional extraoral mandibular distractor (Fig. 8) was placed under general anesthesia after corticotomies on the ramus and mandibular corpus (posterior to the standing teeth). After a latency period of 5 days, distraction was performed at 1 mm/d using a 12-hour rhythm (Fig. 9). After 13 days of distraction for the vertical arm and 33 days for the horizontal arm (Fig. 10), a retention period of 66 days was used.
The DO has become a standard tool of craniofacial and maxillofacial surgeons for the reconstruction of defects such as hypoplasia of the mandible and midface. Other reconstructive options for such defects include orthognatic surgery, bone grafts, and flap surgeries. The DO, however, has the advantage of being a relatively minor surgical procedure producing excellent esthetics and functional results in patients. Other advantages include stimulation of soft tissue growth (skin, nerves, blood vessels, and mucosa), preservation of vascular supply and nerve function, absence of relapse, and the ability to reconstruct relatively large defects. 35,36 One disadvantage of DO is the length of time required for the correction of large defects because an optimal rate of distraction of 1 mm per day must be maintained, as a 1-mm-per-day distraction rate has been found to be the ideal rate of distraction.36 There may also be a need for multiple procedures at various times in the actively growing individual. Disadvantages specific to extraoral devices include their unsightly appearance, extraoral scar formation, and interference with sleeping positions. The need for compliance on the part of the patient or relatives for regular activation of the device also limits the technique. Either external or internal devices can be used to achieve maxillary distraction. External maxillary devices such as the halo frame receive anchorage from percutaneous pins to the skull. Internal devices are surgically placed on either side of maxillary osteotomies and anchored with screws. These devices can aid in
TABLE 3. Preoperative Soft Tissue Measurements for Patient 2
Mandible, mm Deficit, mm
1790
Right
Left
Tragus to angle = 30 Angle to midline = 75 Vertical = 10 (40–30) Horizontal = 25 (100–75)
Tragus to angle = 40 Angle to midline = 100 FIGURE 9. Twenty-two days into distraction phase.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 5, September 2014
FIGURE 12. One year after removal of distractors (frontal and right profile views, respectively).
FIGURE 10. Mouth opening at the end of distraction phase.
TABLE 4. Postoperative Soft Tissue Measurements for Patient 2 Right, mm
Left, mm
40 98
50 100
Mandible Tragus to angle Angle-to-midline
DO in a Nigerian Teaching Hospital
the repositioning of the maxilla but would require separate mandibular distractors to achieve bimaxillary movement. Bimaxillary movement ensures that the mandible and the maxilla are both distracted to correct the facial deformity. A major difficulty with bimaxillary movement is the maintenance of occlusal harmony during distraction.37 The use of MMF with a mandibular distraction device helps to stabilize the movements of the jaws. The MMF ensures that all teeth move as a unit, thus ensuring that only a tilting motion of the maxilla occurs while mandibular lengthening occurs. This eventually corrects the maxillary occlusal canting. The major advantage of this technique is that mandibular deficiencies can be corrected simultaneously with maxillary ones.37 It also has an advantage of steadying or maintaining the occlusion although distraction occurs via using MMF. On the other hand, it does not correct the already-existing occlusal disharmonies, which are common in such cases. The technique is also limited by prolonged MMF and difficulties in balancing mandibular movements with maxillary deficiencies. In our first patient, a complete correction of the occlusal canting could not be achieved because the maximal amount of mandibular lengthening had already been achieved. Thus, distraction was stopped at 5-degree maxillary inclination. A further difficulty with this technique is its complete dependence on the patients’ and relatives’ compliance with instructions regarding activation of the device. Preoperative assessment of patients’ and relatives’ willingness to cope with the demands of DO is essential in treatment planning. An alternative reconstructive option is indicated in situations where patients’ and relatives’ compliance is not assured. The motivation of our patients and their relatives was reflected in the achieved results.
The DO has the ability to reconstruct combined deficiencies in bone and soft tissue, making this technique unique and invaluable to all types of reconstructive surgeons. It can be considered a very special form of fracture healing, representing an effective and long-term augmentation of the human morphology, with the use of mechanical forces to induce and direct bone and soft tissue formation. The DO has been used successfully in the maxillofacial region to correct gross skeletal deformities. It has been applied to lengthen the mandible and36 advance the midface28 and in alveolar bone augmentation,38 among other uses. It provides an excellent option for correcting skeletal deformities such as unilateral mandibular hypoplasia as in our second case. Decisions that need to be made in the presurgical phase include whether the patient can benefit from DO, what type of distractor to use, what osteotomies to be made, and distractor placements. Other treatment options are functional orthodontic appliances and orthognatic surgery. The DO provides strong bone with an excellent blood supply and expansion of the soft tissue envelope around the bone,39 and there is less chance of relapse when compared with orthognatic surgery.40 The gradual expansion of the soft tissue envelope during the period of distraction allows for greater stability of the bone where large movements are made. This makes it a more appealing option than orthognatic surgery. In addition, the use of corticotomies rather than osteotomies ensures bone vitality and preservation of the inferior alveolar nerve. Similarly, slow cutting with a saw or drill accompanied with copious irrigation while cutting preserves bone vitality. Ideal positioning of corticotomies, pins, and distractors also aids distraction.
CONCLUSIONS Our cases represent the pioneer DO treated at the AKTH, Kano, Nigeria. A search of the literature also revealed no previous Nigerian reports of maxillomandibular DO. Despite the availability of other treatment options for midface and mandibular discrepancies such as functional orthodontic appliances and orthognatic surgery, DO provides a reproducible, satisfactory result while producing soft tissue distraction.
REFERENCES
FIGURE 11. Thirteen days after removal of distractors (frontal and right profile views, respectively).
1. Samchukov ML, Cherkashin AM, Cope JB. Distraction osteogenesis: history and biologic basis of new bone formation. In: Lynch SE, Genco RJ, Marx RE, eds. Tissue Engineering: Application in Maxillofacial Surgery and Periodontics. Carol Stream: Quintessence, 1998 2. Yasui N, Kojimoto H, Shimizu H, et al. The effect of distraction upon bone, muscle and periosteum. Orthop Clin North Am 1991;22:563 3. Block MS, Daire J, Stover J, et al. Changes in the inferior alveolar nerve following mandibular lengthening in the dog using distraction osteogenesis. J Oral Maxillofac Surg 1993;51:652 4. Harper RP, Bell WH, Hinton RJ, et al. Reactive changes in the temporomandibular joint after mandibular midline osteodistraction. Br J Oral Maxillofac Surg 1997;35:20
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Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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5. Molina F. Mandibular distraction osteogenesis: a clinical experience of the last 17 years. J Craniofac Surg 2009;20:1794 6. Snyder CC, Levine GA, Swanson HM, et al. Mandibular lengthening by gradual distraction: preliminary report. Plast Reconstr Surg 1973;51:506 7. Illizarov GA. A new principle of osteosynthesis with the use of crossing pins and rings. In: Collection of Scientific Works of the Kurgan Regional Scientific Medical Society. Kurgan: USSR, 1954:145 8. Illazarov GA, Soybelman LM, Chirkova AM. Some roentgenographic and morphologic data on bone tissue regeneration in distraction epiphyscolysis in experiment. Orthop Traumatol Protol 1970;31:26 9. Illazarov GA, Devyatov AA, Kamerin VK. Plastic reconstruction of longitudinal bone defects by means of compression and subsequent distraction. Acta Chir Plast 1980;22:32 10. McCarthy JG, Schreider J, Krp N, et al. Lengthening the human mandible by gradual distraction. Plast Reconstr Surg 1992;89:1 11. Molina F, Ortiz-Monasterio F. Extended indications for mandibular distraction: unilateral, bilateral and bidirectional. Int Craniofac Congress 1993;5:79 12. Molina F. Combined maxillary and mandibular distraction osteogenesis. Semin Orthod 1999;5:41 13. Hoffmeister B, Marks C, Wolff KD. Intraoral callus distraction using the floating bone concept. In: Proceedings of the 55th Annual Meeting of the American Cleft Palate. Baltimore: Craniofacial Association 1998 14. Allen GC. Mandibular distraction osteogenesis for neonatal airway obstruction. Oper Tech Otolaryngol 2005;16:187 15. Aldegheri R, Trivella G, Lavini FM. Epiphyseal distraction: chondrodiasis. Clin Orthop 1989;241:117 16. Fritz MA, Sidman JD. Distraction osteogenesis of the mandible. Curr Opin Otolaryngol Head Neck Surg 2004;12:513 17. Sesenna E, Magri AS, Magnani C, et al. Mandibular distraction in neonates: indications, techniques, results. Italian J Pediatr 2012;38:1 18. Delome RP, Larogue Y, Caouette-Laberage L. Innovative surgical approach for the Pierre Robin anomalad: subperiosteal release of the floor of the mouth musculature. Plast Reconstr Surg 1989;83:960 19. Molina F, Ortiz-Monasterio F. Mandibular elongation and remodeling by distraction: a farewell to major osteotomies. Plast Reconstr Surg 1995;96:825 20. Samchukov ML, Cope JB, Cherkashin AM. Distraction osteogenesis interactive course on CD-ROM. Dallas: Global Med-Net 1999 21. McCarthy JG, Williams JK, Grayson BH, et al. Controlled multiplanar distraction of the mandible: a device development and clinical application. J Craniofac Surg 1998;9:322 22. Diner PA, Martinez H, Tarbar Y, et al. Experience with distraction in maxillary deficiency at Trousseau hospital. In: Abstract book of the International Congress of Cranial and Facial Bone Distraction Processes. Paris, France: Paper #060 1997
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23. Bell WH, Gonzalez M, Samchukov ML, et al. Intraoral widening and lengthening of the mandible by distraction osteogenesis. J Oral Maxillofac Surg 1999;57:548 24. Guerrero GA. Expansion rapida mandibular. Rev Venez Orthod 1990;48:1 25. Triaca A, Minoretti R, Dimai W, et al. Multi-axis intraoral distraction of the mandible, In: Samchukov ML, Cope JB, Cherkashin AM, eds. Craniofacial Distraction Osteogenesis, St Louis: Mosby, 2001:323 26. Triaca A, Minoretti R, Merz B. Treatment of mandibular retrusion by distraction osteogenesis: a new technique. Br J Oral Maxillofac Surg 2004;42:89 27. Lauritzen C, Munro IR, Ross RB. Classification and treatment of hemifacial microstomia. Scand J Plast Reconstr Surg 1988;82:9 28. Rachmiel A, Potparic Z, Jackson IT, et al. Midface advancement by gradual distraction. Br J Plast Surg 1993;46:201 29. Block MS, Cervini D, Chang A, et al. Anterior maxillary advancement using tooth-supported distraction osteogenesis. J Oral Maxillofac Surg 1995;53:561 30. Rachmiel A, Jackson T, Potparic Z, et al. Midface advancement: 1-year follow-up study. J Oral Maxillofac Surg 1995;53:525 31. Polley JW, Figueroa AA, Charbel FT, et al. Monoblock craniomaxillofacial distraction osteogenesis in a newborn with severe craniofacial synostosis: a preliminary report. J Craniofac Surg 1995;6:421 32. Kita H, Kochi S, Imai Y, et al. Rigid external distraction using skeletal anchorage to cleft maxilla united with alveolar bone grafting. Cleft Palate Craniofac J 2005;42:318 33. Chin M, Toth BA. Le Fort III advancement with gradual distraction using internal devices. Plast Reconstr Surg 1997;100:819 34. Molina F. Combined maxillary and mandibular distraction osteogenesis. Semin Orthodont 1999;5:41 35. Ilizarov GA. The tension-stress effect on the genesis and growth of tissues: part II. The influence of the rate and frequency of distraction. Clin Orthop 1989;239:263 36. Ilizarov GA. Clinical application of the tension-stress effect for limb lengthening. Clin Orthop 1990;250:8 37. Ortiz Monasterio F, Molina F, Andrade L, et al. Simultaneous mandibular and maxillary distraction in hemifacial microstomia in adults: avoiding occlusal disasters. Plast Reconstr Surg 1997;100:852 38. Oda T, Sawaki Y, Ueda M. Experimental alveolar ridge augmentation by distraction osteogenesis using a simple device that permits secondary implant placement. Int J Oral Maxillofac Implants 2000;15:95–101 39. Swennen GRJ, Eulzer C, Schutyser F, et al. Assessment of distraction regenerate using three-dimensional quantitative computer tomography. Int J Oral Maxillofac Surg 2005;34:64–73 40. Rachmiel A, Aizenbud D, Pillar G, et al. Bilateral mandibular distraction for patients with compromised airway analyzed by three-dimensional CT. Int J Oral Maxillofac Surg 2005;34:9–18
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Maxillomandibular Distraction Osteogenesis Akinwale A. Efunkoya, BDS, FMCDS,*† Babatunde O. Bamgbose, DDS, MS,†‡ Rafael A. Adebola, BDS, FDSRCPSG FWACS,†§ Joshua B. Adeoye, MBChD,§|| and Izegboya O. Akpasa, BDS#
Background: Distraction osteogenesis (DO) is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction. It consists of 4 primary phases, namely, corticotomy and device placement, a latency period, active distraction, and consolidation. The objectives of the current study were to review DO as it applies to maxillomandibular defects and to share our clinical experience in the cases we have done. Methods: A clinical narrative review of the literature was performed to evaluate the use and efficacy of maxillomandibular osteogenesis in maxillomandibular defects. A systematic search of the literature was performed using PubMed, with special interest in the history of DO and its application in dentistry and maxillofacial surgery. medical subject headings terms included surgical procedures, osteogenesis, distraction, and orthodontics. Two cases of maxillomandibular DO managed at the Aminu Kano Teaching Hospital (AKTH), Nigeria, were reported and discussed. Results: Articles involving maxillary and midface distractions, bilateral distraction for airway obstruction, and distraction for hemifacial microstomia were all reviewed. In the first case reported, a unidirectional distractor was used to achieve simultaneous mandibular lengthening and maxillary occlusal correction. Gains of 10 mm in mandibular ramal height and 23 mm in corpus length were achieved in the second reported case, using a bidirectional distractor. The literature search revealed no previous Nigerian reports of maxillomandibular DO. Conclusions: The DO is a viable and available treatment option for reconstructing maxillomandibular discrepancies and accompanying soft and hard tissue deficiencies. Key Words: Distraction osteogenesis, Pierre Robin sequence, corticotomy, case report (J Craniofac Surg 2014;25: 1787–1792)
From the *Department of Restorative Dentistry, Faculty of Dentistry, Bayero University; †Department of Oral and Maxillofacial Surgery, Aminu Kano Teaching Hospital; Departments of ‡Oral Diagnostic Sciences and §Preventive Dentistry, Faculty of Dentistry, Bayero University; and Departments of ||Public Dental Health and #Child Dental Health, Aminu Kano Teaching Hospital, Kano, Nigeria. Received January 13, 2014. Accepted for publication February 10, 2014. Address correspondence and reprint requests to Akinwale A. Efunkoya, BDS, FMCDS, Faculty of Dentistry, Bayero University, Kano, Nigeria; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000907
BACKGROUND Distraction osteogenesis (DO) is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction.1 It has also been defined as a technique for gradual lengthening of bone by application of a gradual external force over a corticotomized site. The corticotomy preserves the neurovascular bundle, whereas the controlled, progressive, and gradual movements create tension in the surrounding soft tissues, initiating a sequence of adaptive changes termed distraction histiogenesis.1 Active histiogenesis occurs in different tissues, including the gingiva, blood vessels, ligaments, cartilage, muscles, and nerves.2–4 The DO is becoming the treatment of choice in the maxillofacial region, including for midface advancement and for mandibular or alveolar ridge lengthening. It is playing a rapidly expanding role in the treatment of children with airway obstruction associated with bilateral microstomia and Pierre Robin sequence. The DO is less invasive and has a significantly decreased morbidity rate compared with the traditional methods of osseous reconstruction. It also provides the added advantage of expanding the overlying soft tissue.5 Orthodontic appliances can correct resultant postdistraction occlusal changes. After Snyder et al6 introduced the concept of DO7–9 to the craniofacial region, many successful craniofacial distraction procedures have been performed on a multitude of patients worldwide.10–13 The DO consists of 4 primary and consistent phases, namely, device placement and corticotomy; a latency period of primary healing; active distraction (at a rate of 1 mm per day until the desired level of distraction is achieved); and after completion of distraction, an additional period of 4 to 6 weeks during which the devices are left in place to allow the regenerated bone consolidate.14 Aldegheri et al15 classified DO techniques into callotasis and physeal distraction. Callotasis is a gradual stretching of the reparative callus forming around bone segments. The ideal rate of distraction for callotasis is 1 mm/d. Physeal distraction is the distraction of bone growth plates and is divided into epiphysiolysis, which is the loosening or separation, either partial or complete, of the growth plate from the shaft of a bone, with subsequent distraction; and chondrodiastasis, which is a distraction of the growth plate without fracture of the plate. Currently, callotasis is the predominant method used for DO.15 The objectives of the current study were to review DO as it applies to maxillomandibular defects and to share our clinical experience in cases we have done.
METHODS A clinical narrative review of the literature was performed to evaluate the use and efficacy of maxillomandibular osteogenesis in conditions affecting the midface and the mandible. A systematic search of the literature was performed using PubMed, with special interest in the history of DO and its application in dentistry and maxillofacial surgery.
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FIGURE 1. Frontal view of patient, showing preoperative maxillary inclination.
Medical subject headings terms included surgical procedures, osteogenesis, and distraction. Two cases of maxillomandibular DO managed at the AKTH, Nigeria, were also reported and discussed.
Bilateral Distraction for Airway Obstruction Pediatric patients with micrognathia or retrognathia, sleep apnea, and severe respiratory obstruction, most commonly associated with Pierre Robin sequence, Treacher Collins syndrome, Nager syndrome, and velocardiofacial syndrome, benefit greatly from mandibular DO.16 It has led to early decannulation in tracheotomized patients. Sesenna et al17 applied mandibular DO in 10 neonatal patients who all underwent fibroscopic examination of the upper respiratory system to confirm that the obstruction was caused by posterior tongue displacement. Indications for surgery were repeated apneic episodes with severe desaturation, and the patients were treated by mandibular DO when other nonsurgical treatments failed to avoid tracheostomy. The study reported improvement in symptoms and signs of airway obstruction, and tracheostomy, when present, was removed. They reported no injury to the inferior alveolar nerve, and scarring was significant in only 2 patients treated with external devices. The anatomic abnormalities in airway obstruction include retroposition of the mandible and reduced effectiveness of the genioglossus muscle in exerting anterior traction on the tongue.18 Success in improving airways with mandibular distraction is linked to anterior displacement of the tongue with increase in mandibular projection. This is due to the intimate relationship of the genial muscles with the anterior mandible.
TABLE 1. Preoperative Soft Tissue Measurements for Patient 1 Right, mm
Left, mm
Maxilla Lateral canthus of 70 60 eye to commissure of mouth Mandible Tragus to angle 55 35 Others Angle-to-facial 90 80 midline Maxillary occlusal 16 degrees (inclined canting downwards toward the right) Midline shift of 15 mandible to the left Derivatives Deficiency in maxillary vertical height = 10 mm (70–60 mm) Deficiency in mandibular ramus height = 20 mm (55–35 mm) Deficiency in mandibular corpus length = 10 mm (90–80 mm)
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FIGURE 2. Reformatted computerized tomographic scan of patient.
Mandibular Distraction for Hemifacial Microstomia McCarthy et al10 were the first to use miniaturized orthopedic distraction devices for mandibular lengthening. Molina and OritzMonasterio19 simplified the methods established by McCarthy et al by using corticotomy instead of osteotomy. Only 1 fixation pin was inserted on either side of the corticotomy and secured to the distraction device. They were the first to use bidirectional osteodistraction in the mandible. The introduction of extraoral bidirectional distraction devices significantly improved the adaptability of DO in cases of mandibular deficiency.20 After these bidirectional devices, several multidirectional devices have been made. A multidirectional distraction device consists of 2 distractor rods with gradually sliding clamps connected in the middle by a universal hinge. This allows linear or angular correction in the sagittal plane and angular correction in the transverse plane. The trajectory of transport bone segment movement may also be changed during the distraction.21 The advantages22 of extraoral distraction include its application for very small children, simplicity of attachment, ease of manipulation, and bidirectional and multidirectional distractions. The external distractors have the disadvantage of creating a difficult psychosocial challenge for children and adults already dealing with the stigma of a facial deformity. There is also the potential for permanent facial scars. The initial development of intraoral mandibular distraction devices began with the miniaturization of the external devices and the modification of available orthodontic expansion devices.23 Guerrero24 developed a midsymphyseal mandibular widening technique using an intraoral tooth-borne Hyrax-type device, treating 11 patients in his first report with transverse deficiencies ranging from 4 to 7 mm. The multiaxis intraoral distractor is, however, the only true three-dimensional intraoral distractor available.25,26 Molina5 reported a 17-year clinical experience with mandibular distraction to achieve simultaneous skeletal and soft tissue correction. The report includes predominant cases of hemifacial microstomia with clinical features covering facial asymmetry, microtia, deviation of the chin to the affected side, hypoplasia of the soft tissue, and associated disorders of other anatomic structures
FIGURE 3. Facial profile at consolidation phase of treatment.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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TABLE 2. Postoperative Soft Tissue Measurements for Patient 1 Right, mm
Left, mm
72
75
55
70
90
80
Maxilla
FIGURE 4. Frontal view of patient at completion of treatment showing improvement in maxillary inclination.
such as the maxilla, zygoma, and muscles of mastication. Although Molina5 did not mention the number of patients treated during the 17-year period, the clinical series included a group of patients with grade IIB hypoplasia, aged between 18 months and 3 years. Lauritzen et al27 classified hemifacial microstomia as hypoplasia affecting the gonial angle (grade I), the angle and ascending ramus (grades IIA and IIB), and complete absence of ramus and the condyle (grade III). The corticotomy and position of the pins determine the distraction vector and differ in each patient according to the grade of mandibular hypoplasia. The parents did lengthening during the night without disturbing the patient’s sleep. After overcorrection, the use of orthodontic appliances and bite blocks corrected the occlusal changes and the vertical dimension of the maxilla. They reported no permanent dental or neurovascular complications, and the consolidation period was 8 weeks or more, depending on the age of the patient. The authors noted that simultaneous soft tissue expansion is the most important factor in obtaining correction of facial asymmetry.
Maxillary and Midface Distraction Maxillary DO was studied experimentally before it was applied clinically to humans. Rachmiel et al28 first reported its possibility, and Block et al29 in 1995 demonstrated anterior maxillary advancement using tooth-borne distraction devices in dogs. Rachmiel et al30 then reported the multiple segmental distraction of the facial skeleton in 3 young adult sheep with obvious new bone formation clinically, radiographically, and histologically. The results suggested that multiple segmental distractions might provide improved three-dimensional control of complex facial deformities. Polley et al31 were among the first to use midface distraction clinically, using an externally fixed cranial halo to distract the midface. The rigid external distractor is an example of such device.32 Its advantages include ease of intraoral application, ease of activation by the patient, and capacity for removal without the need for a second operation at the completion of consolidation. Chin and Toth33 reported on patients who underwent Le Fort III midface advancements with gradual distraction using intraoral devices. Their protocol was different from the traditional IIizarov protocol (tension-stress effect and influence on blood supply) with no latency period. Distraction was initiated intraoperatively and
FIGURE 5. Postoperative radiograph of patient.
Lateral canthus of eye to commissure of mouth Mandible Tragus to angle Others Angle-to-facial midline
often completed in the early postoperative period. The devices could be left in situ, and the authors discovered that long-term stability was good. Molina34 further introduced a technique for simultaneous mandibular and maxillary distraction using only mandibular devices. The technique involved an incomplete Le Fort I osteotomy and a mandibular corticotomy. After a 5-day latency period, intermaxillary fixation was applied, and mandibular distraction was initiated. As the mandible was elongated, the maxilla was moved with it.
CLINICAL REPORT We present our experience with DO at the AKTH, Kano. To the best of our knowledge, these are the first cases of DO reported in Nigeria. The first is an 18-year-old woman who presented with a complaint of “I don't like my facial appearance.” There was a history of left preauricular swelling and pus discharge at 9 months old with progressive deviation of her face to the left side, as she grew older. On examination, obvious facial asymmetry was observed. The left pinna was deformed, and the patient was noted to have a left-sided facial palsy. The mandible was deviated to the left side, the midline was also deviated to the left, and the left ramal height was shortened. The left hemimaxilla was hypoplastic when compared with the right causing a superior inclination of the maxillary occlusal plane on the left (Fig. 1). In profile, the chin was retrognathic. The patient’s mouth opening was, however, adequate. An assessment of the left hemifacial microstomia secondary to condylar hypoplasia was made, and the patient planned for a bimaxillary DO. Preoperative soft tissue measurements were done to estimate the amount of movement required, as outlined in Table 1. With these measurements in mind, planned regenerated (new bone formed by distraction) lengths were 30-mm forward mandibular corpus distraction and 20-mm downward vertical distraction for both the maxilla and the mandible. A vector distance of 36 mm was calculated at 30 degrees at the mandibular angle to achieve these goals.
FIGURE 6. Preoperative pictures of patient (frontal and right profile views, respectively).
© 2014 Mutaz B. Habal, MD
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FIGURE 7. Preoperative picture of patient (left profile and mouth-open views, respectively).
FIGURE 8. Two days postoperative (frontal and right profile views, respectively).
A computerized tomographic scan (Fig. 2) was done for better assessment of the skeletal deformities. The patient underwent the following: maxillary Le Fort I osteotomy, left mandibular angle corticotomy with insertion of an extraoral unidirectional mandibular distractor, and maxillomandibular fixation (MMF) using eyelets and tie wires. A latency period of 7 days was observed, after which the device was activated at a rate of 1 mm per day with a 12-hour rhythm (0.5 mm). The distraction phase was continued for 36 days (35.5-mm movement on device), and consolidation was done for a further 70 days (Figs. 3–5).
Surgical Outcome for Patient 2 At completion of treatment, the patient had gained 10 mm in ramus height and 23 mm in body length. Postoperative jaw dimensions at the end of retention period were shown in Table 4. The patients’ postoperative appearance was satisfactory at the completion of treatment (Fig. 11), and the postconsolidation phase was uneventful. He was placed on regular reviews up to 1 year postoperatively (Fig. 12) and is being planned for further right hemimandibular distraction at ages 16 and 21 years in anticipation of continued left hemimandibular growth.
DISCUSSION
Surgical Outcome for Patient 1 Correction of the maxillary occlusal canting was achieved at the completion of treatment by a combination of maxillary downward distraction and mandibular forward distraction using Le Fort I and angular corticotomies, respectively. At completion of distraction, there was a visibly improved facial profile with postoperative measurements outlined in Table 2. The maxillary occlusal canting had reduced to 5 degrees. The second patient was a 12-year-old boy who presented with a complaint of unequal growth of the lower jaw for 7-year duration. His parents, both nurses, noticed the inequality in growth at approximately 5 years, with the deficiency on the right side. There was history of previous trauma (fall from the bed at 2 years old). There was no limitation of mouth opening, difficulty with chewing, airway obstruction, or associated speech problems. On examination, the patient was found to have a shorter, smaller right hemimandible with midline deviation to the right (Figs. 6, 7), with obtained measurements presented in Table 3. A diagnosis of the right unilateral mandibular hypoplasia secondary to trauma was made. The patient was planned for DO to increase ramus height and mandibular corpus length. A bidirectional extraoral mandibular distractor (Fig. 8) was placed under general anesthesia after corticotomies on the ramus and mandibular corpus (posterior to the standing teeth). After a latency period of 5 days, distraction was performed at 1 mm/d using a 12-hour rhythm (Fig. 9). After 13 days of distraction for the vertical arm and 33 days for the horizontal arm (Fig. 10), a retention period of 66 days was used.
The DO has become a standard tool of craniofacial and maxillofacial surgeons for the reconstruction of defects such as hypoplasia of the mandible and midface. Other reconstructive options for such defects include orthognatic surgery, bone grafts, and flap surgeries. The DO, however, has the advantage of being a relatively minor surgical procedure producing excellent esthetics and functional results in patients. Other advantages include stimulation of soft tissue growth (skin, nerves, blood vessels, and mucosa), preservation of vascular supply and nerve function, absence of relapse, and the ability to reconstruct relatively large defects. 35,36 One disadvantage of DO is the length of time required for the correction of large defects because an optimal rate of distraction of 1 mm per day must be maintained, as a 1-mm-per-day distraction rate has been found to be the ideal rate of distraction.36 There may also be a need for multiple procedures at various times in the actively growing individual. Disadvantages specific to extraoral devices include their unsightly appearance, extraoral scar formation, and interference with sleeping positions. The need for compliance on the part of the patient or relatives for regular activation of the device also limits the technique. Either external or internal devices can be used to achieve maxillary distraction. External maxillary devices such as the halo frame receive anchorage from percutaneous pins to the skull. Internal devices are surgically placed on either side of maxillary osteotomies and anchored with screws. These devices can aid in
TABLE 3. Preoperative Soft Tissue Measurements for Patient 2
Mandible, mm Deficit, mm
1790
Right
Left
Tragus to angle = 30 Angle to midline = 75 Vertical = 10 (40–30) Horizontal = 25 (100–75)
Tragus to angle = 40 Angle to midline = 100 FIGURE 9. Twenty-two days into distraction phase.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 5, September 2014
FIGURE 12. One year after removal of distractors (frontal and right profile views, respectively).
FIGURE 10. Mouth opening at the end of distraction phase.
TABLE 4. Postoperative Soft Tissue Measurements for Patient 2 Right, mm
Left, mm
40 98
50 100
Mandible Tragus to angle Angle-to-midline
DO in a Nigerian Teaching Hospital
the repositioning of the maxilla but would require separate mandibular distractors to achieve bimaxillary movement. Bimaxillary movement ensures that the mandible and the maxilla are both distracted to correct the facial deformity. A major difficulty with bimaxillary movement is the maintenance of occlusal harmony during distraction.37 The use of MMF with a mandibular distraction device helps to stabilize the movements of the jaws. The MMF ensures that all teeth move as a unit, thus ensuring that only a tilting motion of the maxilla occurs while mandibular lengthening occurs. This eventually corrects the maxillary occlusal canting. The major advantage of this technique is that mandibular deficiencies can be corrected simultaneously with maxillary ones.37 It also has an advantage of steadying or maintaining the occlusion although distraction occurs via using MMF. On the other hand, it does not correct the already-existing occlusal disharmonies, which are common in such cases. The technique is also limited by prolonged MMF and difficulties in balancing mandibular movements with maxillary deficiencies. In our first patient, a complete correction of the occlusal canting could not be achieved because the maximal amount of mandibular lengthening had already been achieved. Thus, distraction was stopped at 5-degree maxillary inclination. A further difficulty with this technique is its complete dependence on the patients’ and relatives’ compliance with instructions regarding activation of the device. Preoperative assessment of patients’ and relatives’ willingness to cope with the demands of DO is essential in treatment planning. An alternative reconstructive option is indicated in situations where patients’ and relatives’ compliance is not assured. The motivation of our patients and their relatives was reflected in the achieved results.
The DO has the ability to reconstruct combined deficiencies in bone and soft tissue, making this technique unique and invaluable to all types of reconstructive surgeons. It can be considered a very special form of fracture healing, representing an effective and long-term augmentation of the human morphology, with the use of mechanical forces to induce and direct bone and soft tissue formation. The DO has been used successfully in the maxillofacial region to correct gross skeletal deformities. It has been applied to lengthen the mandible and36 advance the midface28 and in alveolar bone augmentation,38 among other uses. It provides an excellent option for correcting skeletal deformities such as unilateral mandibular hypoplasia as in our second case. Decisions that need to be made in the presurgical phase include whether the patient can benefit from DO, what type of distractor to use, what osteotomies to be made, and distractor placements. Other treatment options are functional orthodontic appliances and orthognatic surgery. The DO provides strong bone with an excellent blood supply and expansion of the soft tissue envelope around the bone,39 and there is less chance of relapse when compared with orthognatic surgery.40 The gradual expansion of the soft tissue envelope during the period of distraction allows for greater stability of the bone where large movements are made. This makes it a more appealing option than orthognatic surgery. In addition, the use of corticotomies rather than osteotomies ensures bone vitality and preservation of the inferior alveolar nerve. Similarly, slow cutting with a saw or drill accompanied with copious irrigation while cutting preserves bone vitality. Ideal positioning of corticotomies, pins, and distractors also aids distraction.
CONCLUSIONS Our cases represent the pioneer DO treated at the AKTH, Kano, Nigeria. A search of the literature also revealed no previous Nigerian reports of maxillomandibular DO. Despite the availability of other treatment options for midface and mandibular discrepancies such as functional orthodontic appliances and orthognatic surgery, DO provides a reproducible, satisfactory result while producing soft tissue distraction.
REFERENCES
FIGURE 11. Thirteen days after removal of distractors (frontal and right profile views, respectively).
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Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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5. Molina F. Mandibular distraction osteogenesis: a clinical experience of the last 17 years. J Craniofac Surg 2009;20:1794 6. Snyder CC, Levine GA, Swanson HM, et al. Mandibular lengthening by gradual distraction: preliminary report. Plast Reconstr Surg 1973;51:506 7. Illizarov GA. A new principle of osteosynthesis with the use of crossing pins and rings. In: Collection of Scientific Works of the Kurgan Regional Scientific Medical Society. Kurgan: USSR, 1954:145 8. Illazarov GA, Soybelman LM, Chirkova AM. Some roentgenographic and morphologic data on bone tissue regeneration in distraction epiphyscolysis in experiment. Orthop Traumatol Protol 1970;31:26 9. Illazarov GA, Devyatov AA, Kamerin VK. Plastic reconstruction of longitudinal bone defects by means of compression and subsequent distraction. Acta Chir Plast 1980;22:32 10. McCarthy JG, Schreider J, Krp N, et al. Lengthening the human mandible by gradual distraction. Plast Reconstr Surg 1992;89:1 11. Molina F, Ortiz-Monasterio F. Extended indications for mandibular distraction: unilateral, bilateral and bidirectional. Int Craniofac Congress 1993;5:79 12. Molina F. Combined maxillary and mandibular distraction osteogenesis. Semin Orthod 1999;5:41 13. Hoffmeister B, Marks C, Wolff KD. Intraoral callus distraction using the floating bone concept. In: Proceedings of the 55th Annual Meeting of the American Cleft Palate. Baltimore: Craniofacial Association 1998 14. Allen GC. Mandibular distraction osteogenesis for neonatal airway obstruction. Oper Tech Otolaryngol 2005;16:187 15. Aldegheri R, Trivella G, Lavini FM. Epiphyseal distraction: chondrodiasis. Clin Orthop 1989;241:117 16. Fritz MA, Sidman JD. Distraction osteogenesis of the mandible. Curr Opin Otolaryngol Head Neck Surg 2004;12:513 17. Sesenna E, Magri AS, Magnani C, et al. Mandibular distraction in neonates: indications, techniques, results. Italian J Pediatr 2012;38:1 18. Delome RP, Larogue Y, Caouette-Laberage L. Innovative surgical approach for the Pierre Robin anomalad: subperiosteal release of the floor of the mouth musculature. Plast Reconstr Surg 1989;83:960 19. Molina F, Ortiz-Monasterio F. Mandibular elongation and remodeling by distraction: a farewell to major osteotomies. Plast Reconstr Surg 1995;96:825 20. Samchukov ML, Cope JB, Cherkashin AM. Distraction osteogenesis interactive course on CD-ROM. Dallas: Global Med-Net 1999 21. McCarthy JG, Williams JK, Grayson BH, et al. Controlled multiplanar distraction of the mandible: a device development and clinical application. J Craniofac Surg 1998;9:322 22. Diner PA, Martinez H, Tarbar Y, et al. Experience with distraction in maxillary deficiency at Trousseau hospital. In: Abstract book of the International Congress of Cranial and Facial Bone Distraction Processes. Paris, France: Paper #060 1997
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23. Bell WH, Gonzalez M, Samchukov ML, et al. Intraoral widening and lengthening of the mandible by distraction osteogenesis. J Oral Maxillofac Surg 1999;57:548 24. Guerrero GA. Expansion rapida mandibular. Rev Venez Orthod 1990;48:1 25. Triaca A, Minoretti R, Dimai W, et al. Multi-axis intraoral distraction of the mandible, In: Samchukov ML, Cope JB, Cherkashin AM, eds. Craniofacial Distraction Osteogenesis, St Louis: Mosby, 2001:323 26. Triaca A, Minoretti R, Merz B. Treatment of mandibular retrusion by distraction osteogenesis: a new technique. Br J Oral Maxillofac Surg 2004;42:89 27. Lauritzen C, Munro IR, Ross RB. Classification and treatment of hemifacial microstomia. Scand J Plast Reconstr Surg 1988;82:9 28. Rachmiel A, Potparic Z, Jackson IT, et al. Midface advancement by gradual distraction. Br J Plast Surg 1993;46:201 29. Block MS, Cervini D, Chang A, et al. Anterior maxillary advancement using tooth-supported distraction osteogenesis. J Oral Maxillofac Surg 1995;53:561 30. Rachmiel A, Jackson T, Potparic Z, et al. Midface advancement: 1-year follow-up study. J Oral Maxillofac Surg 1995;53:525 31. Polley JW, Figueroa AA, Charbel FT, et al. Monoblock craniomaxillofacial distraction osteogenesis in a newborn with severe craniofacial synostosis: a preliminary report. J Craniofac Surg 1995;6:421 32. Kita H, Kochi S, Imai Y, et al. Rigid external distraction using skeletal anchorage to cleft maxilla united with alveolar bone grafting. Cleft Palate Craniofac J 2005;42:318 33. Chin M, Toth BA. Le Fort III advancement with gradual distraction using internal devices. Plast Reconstr Surg 1997;100:819 34. Molina F. Combined maxillary and mandibular distraction osteogenesis. Semin Orthodont 1999;5:41 35. Ilizarov GA. The tension-stress effect on the genesis and growth of tissues: part II. The influence of the rate and frequency of distraction. Clin Orthop 1989;239:263 36. Ilizarov GA. Clinical application of the tension-stress effect for limb lengthening. Clin Orthop 1990;250:8 37. Ortiz Monasterio F, Molina F, Andrade L, et al. Simultaneous mandibular and maxillary distraction in hemifacial microstomia in adults: avoiding occlusal disasters. Plast Reconstr Surg 1997;100:852 38. Oda T, Sawaki Y, Ueda M. Experimental alveolar ridge augmentation by distraction osteogenesis using a simple device that permits secondary implant placement. Int J Oral Maxillofac Implants 2000;15:95–101 39. Swennen GRJ, Eulzer C, Schutyser F, et al. Assessment of distraction regenerate using three-dimensional quantitative computer tomography. Int J Oral Maxillofac Surg 2005;34:64–73 40. Rachmiel A, Aizenbud D, Pillar G, et al. Bilateral mandibular distraction for patients with compromised airway analyzed by three-dimensional CT. Int J Oral Maxillofac Surg 2005;34:9–18
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