- Email: [email protected]
Lengthening of the mandible by distraction osteogenesis
838
MANDIBULAR DISTRACTION
J Oral Maxillofac Surg 53:838-846, 1995
Lengthening of the Mandible by Distraction Osteogenesis: Report of Cases ADI RACHMIEL, DMD,* MARK LEVY, MD, DSc,1- AND DOV LAUFER, DMD::I: Distraction osteogenesis is a technique of generating new bone by stretching the callus. This concept o f bone lengthening was first described by Codivilla in 1905,1 who used it to elongate a femur by repeated distraction forces. Other investigators also applied the technique, but it remained undeveloped because of associated complications such as nonunion, nerve damage, local edema, skin necrosis, and pin tract infection. 2'3 However, the technique of bone lengthening by gradual distraction was further developed and popularized by Ilizarov 4'5 in Russia and applied to the enchondral bones o f the upper and lower extremities. Lengthening o f the mandible 6-9 and midface 1° has been described in several animal studies. Recently McCarthy et al ~1described lengthening o f the human mandible by distraction osteogenesis using an extraoral a p p r o a ~ , The technique involves performing a cortic o t o m y on the buccal and lingual aspect o f the mandible, with preservation of the periosteum and the intramedullary blood supply. The distraction device is mounted on both sides of the corticotomy and a latency period of 5 to 10 days is allowed for primary callus organization. Then gradual distraction is performed at the rate o f 0.5 to 1.5 m m per day. After the desired lengthening has been achieved, a period of consolidation of a few weeks is suggested before removal o f the device. In this article we report lengthening o f the human mandible by gradual distraction using an intraoral approach for the corticotomy and an extraoral bone lengthening device.
dibular micrognathia underwent bilateral mandibular expansion. The patients ranged in age from 9 to 14 years. The procedure was performed under general anesthesia. An intraoral incision, 3 cm in length, was made over the external oblique line. Using a periosteal elevator, the buccal and lingual cortex was exposed in the lower portion of the mandibular ramus and the angle region. With a side cutting bur, horizontal buccal and lingual corticotomies were made in that part of the ramus below the entrance of the inferior alveolar nerve (Fig 1A). To complete a circumferential corticotomy, the cortex in the anterior and posterior part of the ramus was cut. A fiberoptic retractor was used to protect the periosteum and the inferior alveolar nerve while cutting. The expander device pins were placed in the p0~erior part of the ramus to avoid damage to the inferior alveolar nerve and to create a forward and downward vector of lengthening (Fig 1A). The pins were introduced transcutaneously through two small incisions 3 mm long. Once the end of the drill guide was exposed intraorally a self-retaining retractor hbld the clLeek tissue away from the end, allowing improved visualiza](i~n. Using a 1.5mm drill bit introduced through the drill guide sleeve, two holes were drilled at a distance of 10 and 14 mm, respec-
Report of Cases Two children with hemifacial microsomia underwent unilateral mandibular expansion, and one child with severe manReceived from the Department of Oral and Maxillofacial Surgery, Rambam Medical Center and the Technion Faculty of Medicine, Haifa, Israel. * Senior Consultant. t Resident. $ Professor and Head. Address correspondence and reprint requests to Dr Rachmiel: The Seldin Institute, Oral and Maxillofacial Surgery, Rambam Medical Center, Haifa 35 254, Israel. © 1995 American Association of Oral and Maxillofacial Surgeons 0278-2391/95/5307-001953.00/0
0 FIGURE 1. A, Diagram of the expansion device and the horizontal corticotomy in the inferior part of the ramus and B, oblique corticotomy in the genial region.
RACHMIEL, LEVY, AND LAUFER
FIGURE 2. A 9-year-old girl with severe micrognathia. A, Predistraction anteroposterior appearance. B, Predistraction profile view. C, Predistraction occlusion. Note the Class II relationship. D, Lateral cephalogram showing the severe mandibular micrognathia.
839
840
FIGURE 3. A, Patient at the beginning of lengthening with the expansion device bilaterally. B, A short pin was added (arrow) to produce forward lengthening of the mandible. C, View of patient after forward advancement of 22 ram. D, E, Patient after removal of the expansion device. (Continued next page)
MANDIBULAR DISTRACTION
RACHMIEL, LEVY, AND LAUFER
841
FIGURE 3. (Cont'd). F, G, Intraoral view of the occlusion. There is a slight tendency to an open bite.
tively, from the corticotomy (Fig 1A). Self-tapping pins were then inserted bicortically into the holes. These pins were 2 mm in diameter and 39 to 50 mm in length, according to the thickness of the cheek. Next a narrow osteotome was introduced to complete the corticotomy, following which a larger osteotome was used to produce slight movement between the two bony segments. Great care was taken not to damage the inferior alveolar nerve while executing this maneuver. When the major movement needed was forward, as in the case of severe micrognathia, the orientation of the corticotomy line was oblique toward the mandibular angle to keep the posterior part of the ramus intact (Fig 1B). The intraoral incision was closed with 3-0 Vicryl (Ethicon, Somerville, NJ) sutures, and the distraction apparatus was then attached to the pins extraorally. The patients received intravenous cephalosporin 50 mg&g per day for 5 days. After a latency period of 7 days, the device was lengthened 1 mm per day for 21 days by turning the bolt. Following the period of gradual distraction the device was used for retention for 7 additional weeks. In the patient with the severe micrognathia (Fig 2), after a lengthening of 5 mm, a short pin was added to the superior two interosseous pins of the device to change the direction of the lengthening and to produce a forward movement of the mandibular body (Figs 3 and 4).
Results A l l the surgical wounds healed uneventfully and there were no signs o f infection around the pins. The neurosensory integrity o f the inferior alveolar nerve, evaluated by touch discrimination, r e v e a l e d no sensory deficit in any o f the patients. In the two patients with hemifacial m i c r o s o m i a , a vertical lengthening in the ramus concomitant with a forward shift of m a n d i b l e was obtained (Figs 5 and 6). Intraorally there was m o v e m e n t o f the occlusion, with a shift to a Class I relation. Panoramic radiographs demonstrated elongation o f the rarnus after 21 days o f distraction (Fig 7 A and B). The e x p a n d e d area was filled with b o n e that was slightly less radiodense than the adjacent bone. A f t e r 7 additional weeks, the radiographs demonstrated increased radiodensity o f the bone (Fig 7C). The patient with severe micrognathia (Figs 2, 3, and 4) tended to d e v e l o p an open bite, which was corrected during the lengthening procedure by adding a pin to the device on both sides to change the direction o f
842
MANDIBULAR DISTRACTION
FIGURE 4. A, Panoramic radiograph of patient with the devices before commencement of forward lengthening. B, Cephalometric radiographs of the patient after bilateral 20 mm forward lengthening of the mandible. C, Panoramicradiographafter mandiblelengthening in the gonial region. The expanded area is filled with bone. lengthening (Fig 3B). A marked forward advancement of 22 m m was obtained. The patient needed additional orthodontic treatment for final adjustment of the occlusion. In all cases residual skin scars were noted in the p i n insertion points. After the device was removed there was no change in the occlusion.
Discussion Reconstruction of the severe hypoplastic mandible in young children is usually done with a costochondral
bone graft, followed by maxillomandibular fixation for several weeks. 1zI3 One of the drawbacks of a costochondral graft is the unpredictability of its growth, producing an excessive increase in mandibular length in some cases, an inadequate rate of growth in others, and in some cases no growth at all. 14-16Other complications with costochondral grafts are infection or resorption, 17 as well as the potential for such donor site morbidity as pneumothorax, scarring, a mild chest wall contour defect, and postoperative pain. 18 Lengthening of endochondral bones by distraction osteogenesis has been used successfully to achieve lengthening of the long bones of the extremities by up to 30 c m . 4'5 Previous animal studies have demonstrated that bone lengthening by gradual distraction is also applicable to membranous bones such as the mandible 69 and the maxilla. 1° Recently, it has been practiced successfully on the hypoplastic mandible of children with hemifacial microsomia and Nager syndrome. 11 The operation was performed through an extraoral approach. In our patients corticotomy was performed through a small intraoral incision, followed by subperiosteal tunneling, to preserve the periosteum and permit maxim u m osteogenic potential. The importance of an uninterrupted periosteal layer over the distracted area has been documented previously. 19'2° Only the cortex is osteotomized to preserve the medullary blood supply. 5 Although this preservation has been shown to optimize bone regeneration, other investigators 2°23 have demonstrated that preservation of the medullary blood supply is not absolutely necessary for success. To facilitate the lengthening, we placed an osteotome in the corticotomy to produce a slight movement between the two bony segments. Great care was taken not to separate completely the two segments, which could damage the inferior alveolar nerve. Another potential for nerve damage could be from pin insertion; therefore, the pins were placed in the posterior part of the mandibular ramus and angle, under direct intraoral visualization. It is known that craniofacial skeletal development is influenced by the functional matrix 24 so that mandibular growth occurs secondarily in response to demands of the attached neuromuscular system and functioning spaces. Enlow 25 also demonstrated that mandibular growth is dependent on the development of the masticatory muscles and eruption of the dentition. Ilizarov 5 reported that with bone distraction there is associate lengthening of the soft tissues, including muscles, nerves, and skin. It can therefore be concluded that mandibular lengthening by gradual distraction not only results in expansion of the jaw but also the attached muscles and soft tissues, with further influence on the expanded mandible. In an animal study 26 in which major midface ad-
RACHMIEL, LEVY, AND LAUFER
843
FIGURE 5. A 14-year-oldboy with right-sided hemifacial microsomia. A, Predistraction appearance. B, Predistraction occlusion. Note the Class II relationship. C, Panoramic radiograph showing the hypoplasia of the right mandibular ramus.
vancement was performed by gradual distraction (40 mm) there was only 7% relapse after 1 year. Histologic studies of the distracted membranous bone showed the formation of mature cortical b o n e . 8'27 This demonstrates that the expanded bone is of high quality and may have good long-term stability and potential for growth in children. Use of the sagittal split ramus osteotomy to correct mandibular retrognathism has been reported to involve a postsurgical neurosensory complication rate ranging from 0% to 5 4 % . 28 Block et a129 showed that distraction osteogenesis can be applied to the mandible with minimal neurosensory effect. The slow nerve stretching in distraction osteogenesis may result in minimal injury because less axonal tearing and less complete compression of the vasa nervorum occur. Young patients with a severely hypoplastic mandible especially benefit from this technique, which obviates the use of a bone graft with its possible complications and the need for maxillomandibular fixation. In hemifacial microsomia patients the vector of traction is vertical in the posterior part of the ramus. This permits an elongation of the short ramus and forward movement of the mandibular body, with correction of
the occlusion and achievement of symmetrical appearance. However, there is a versatility of lengthening direction by distraction osteogenesis. According to the desired direction of mandibular movement, it is possible to place the corticotomy in different sites and orientations such as horizontal in the ramus for hemifacial microsomia or oblique in the angle for both vertical lengthening of the ramus and forward advancement of the mandible. During the gradual distraction there is the possibility of changing the direction of lengthening by making simple changes on the apparatus. In the patient with severe micrognathia the vector of elongation was forward and downward followed by major forward advancement of the mandible. To overcome the tendency of open bite, the simple adding of a pin to the device can change the direction of lengthening in the desired vector. One of the drawbacks of distraction of bone by an extraoral approach are the residual skin scars on the cheek.H To minimize these problems an intraoral approach was used for the corticotomy, and two small incisions were used for pin insertion. Another drawback of an extraoral approach is the potential for dam-
844
MANDIBULAR DISTRACTION
FIGURE 6. A, Patient immediately after surgery with the expansion device. B, View of patient after a 20 mm distraction~ C, The patient after removal of the expansion device. The mandible is more symmetrical and the midpoint of the chin has moved medially. D, Intraoral view of the occlusion. Note the change to a Class I relationship.
845
RACHMIEL, LEVY, AND LAUFER
FIGURE 7. A, The panoramic radiographs of the patient in Figure 6. Device before commencement of distraction. Note the corticotomy (arrow). The unerupted third molar was extracted. B, Completion of ramus distraction. The expanded area is filled with bone (between arrows). C, The elongated ramus after removal of the device.
age to the m a n d i b u l a r branch o f the facial nerve. De. device 30 m a y offer the veloping an intraoral distraction advantages o f an extraoral device without the need for a cutaneous incision and resulting scar. •
Acknowledgment
13. 14. 15.
The authors thank Howmedica lnc, Rutherford, NJ for their generous help in providing the distraction apparatus.
16.
References
17.
1. Codivilla A: On the means of lengthening in the lower limbs, muscles and tissues which are shortened through deformity. Am J Orthop Surg 2:353, 1905 2. Abbott LC: The operative lengthening of the tibia and fibula. J Bone Joint Surg [Br] 9:128, 1927 3. Abbott LC, Saunders JB: The operative lengthening of the tibia and fibula: A preliminary report in the further development of principles and technique. Ann Surg 110:961, 1939 4. Ilizarov GA: The principles of the Ilizarov method. Bull Hosp Jt Dis Orthop Inst 48:1, 1988 5. Ilizarov GA, Devyatov AA, Karnerim VK: Plastic reconstruction of longitudinal bone defects by means of compression and subsequent distraction. Acta Chir Plast 22:32, 1980 6. Snyder CC, Levine GA, Swanson HM, et al: Mandibular lengthening by gradual distraction. Plast Reconstr Surg 51:506, 1973 7. Michieli S, Miotti B: Lengthening of mandibular body by gradua~ surgical-orthodontic distraction. J Oral Surg. 35:187, 1977 8. Karp NS, Thorne CHM, McCarthy JG, et al: Bone lengthening in the craniofacial skeleton. Ann Plast Snrg 24:231, 1990 9. Karaharju T, Karaharju EO, Ranta R: Mandibular distraction: An experimental study on sheep. J Craniomaxillofac Surg 18:280, 1990 10. Rachmiel A, Potparic Z, Jackson IT, et al: Midface advancement by gradual distraction. Br J Plast Surg 46:201, 1993 11. McCarthy JG, Schreiber J, Karp N, et al: Lengthening of mandible by gradual distraction. Plast Reconstr Surg 89:1, 1992 12. Kaban LB, Moses MH, Mulliken JB: Surgical correction of
18.
19.
20.
21.
22.
23.
24. 25. 26.
hemifacial microsomia in the growing child. Plast Reconstr Surg 82:9, 1988 Mulliken JB, Kaban LB: Analysis and treatment of hemifacial microsomia in childhood. Clin Plast Surg 14:91, 1987 McIntosh RB, Henny FA: A spectrum of application of autogenous costochondral grafts. J Maxillofac Surg 5:257, 1977 Politics C, Fossion E, Bossuyt M: The use of eostochondral graft in arthroplasty of the temporomandibular joint. J Craniomaxillofac Surg 15:345, 1987 Munro IR, Philips JH, Griffin G: Growth and construction of the temporomandibular joint in children with hemifacial microsomia. Cleft ]Palate J 26:303, 1989 Mclntosh RB: Cun:ent spectrum of costochondral grafting, in Bell WH (ed): Surgical Correction of Dentofacial Deformities: New concepts, vol 3. Philadelphia, PA, Saunders, 1985, pp 355-410 Laurie SW, Kaban LB, Mulliken JB, et al: Donor site morbidity after harvesting rib and iliac bone. Plast Reconstr Surg 73:933, 1984 Kojimoto H, Yasui N, Goto T, et al: Bone lengthening in rabbits by callus distraction: The role of periosteum and endosteum. J Bone Joint Surg [Br] 70:543, 1988 Delloye C, Delefortrie G, Coutelier L, et al: Bone regenerate formation in cortical bone during distraction lengthening: An experimental study. Clin Orthop 250:34, 1990 DeBastiani G, Oldegheri R, Ranzi-Brivio L, et al: Limb lengthening by callus distraction (callostasis). J Pediatr Orthop 7:129, 1987 Constantino PD, Shybut G, Friedman CD, et al: Segmental mandibular regeneration by distraction osteogenesis. Arch Otolaryngol Head Neck Surg 116:535, 1990 Phillips JH, Forrest CR, Gruss JS: Current concepts in the use of bone grafts in facial fractures. Clin Plast Surg 19:41, 1992 Moss ML, Rankow RM: The role of functional matrix in mandibular growth, Angle Orthod 38:93, 1968 Enlow DH: Handbook of Facial Growth (ed 2). Philadelphia, PA, Saunders, 1982 Rachmiel A, Jackson IT, Clayman L, et al: Midface advancement by gradual distraction: A follow-up study. Presented at V International Congress of Craniofacial Surgery, Oaxaca, Mexico, October 1993
846
MICROCYSTIC ADNEXAL CARCINOMA
27. Karp NS, McCarthy JG, Schreiber JS, et al: Membranous bone lengthening:A serial histological study. Ann Plast Surg 29:2, 1992 28. Karns P, Nester D, Boyd C, et al: Recovery of neurosensory function following orthognathic surgery. J Oral Maxillofac Surg 48:124, 1990 29. 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 51:652, 1993 30. StaffenbergDA, Wood JR, McCarthy JG: Mandibularlengthening in the canine using an intraoral device. Presented at V International Congress of Craniofacial Surgery, Oaxaca, Mexico, October 1993
J Oral Maxillofac Surg 53:846-849, 1995
Microcystic Adnexal Carcinoma: Report of a Case MICHAEL L. ROBINSON, MD, DMD,* MARK A. KNIBBE, MD, DDS,* AND JOHN B. ROBERSON, DMD~f Microcystic adnexal carcinoma (MAC) is a recently described n e o p l a s m with c o m b i n e d pilar and eccrine differentiation that is characterized by a locally aggressive growth pattern. ~ Wallace and Bernstein2 reported that M A C occurs primarily on the faces of y o u n g and middle-aged w o m e n ; however Borenstein et al 3 state that males and females are affected equally. This entity can be clinically and histologically confused with other malignant and b e n i g n cutaneous neoplasms, which may lead to inadequate initial treatment and extensive recurrence. 4 W e present a case of M A C in a middleaged m a n who received radiation therapy as an adolescent for the treatment of acne.
Report of Case A 53-year-old white man was evaluated in our office after visiting his dermatologist and general dentist. The patient had a cutaneous lesion in the left mental region for approximately 2-years. The lesion was 4 x 4 cm in size and had irregular margins. It was nontender and had an erythematous cutaneous surface (Figs 1, 2). The patient's medical history was essentially negative, although he did receive radiation treatment for acne as an adolescent. The social history was negative for tobacco and alcohol abuse. An incisional biopsy was performed under local anesthesia in the office on July 31, 1992. Microscopic examination of
* In .private practice, Oral and Maxillofacial Surgery, Edgewood, KY. "~Resident, Oral and MaxillofacialSurgery, University of Cincinnati, Cincinnati, OH. Address correspondence and reprint requests to Dr Knibbe: 20 Medical Village Dr, Suite 196, Edgewood, KY 41017. © 1995 American Association of Oral and Maxillofacial Surgeons 0278-2391/95/5307-002053.00/0
the specimen showed stratified squamous epithelium, pilesebaceous structures, supporting connective tissue, and an adnexal neoplasm (Fig 3). Within the superficial connective tissue were numerous microcysts that were filled with a keratinlike material (Fig 4). There were several layers of flattened cuboidal cells lining the microcysts. The individual microcysts were not well delineated and extended into the underlying connective tissue. The tumor was infiltrating between muscle fibers and approached segments of peripheral nerve (Fig 5). The histologic findings were consistent with a diagnosis of MAC. One week later the patient was taken to the operating room for removal of the lesion and immediate reconstruction. The lesion was marked with 1-cm margins from the palpable tumor. The planned excision encompassed an area measuring 6.5 cm anteroposterior and 6 cm superoinferiorly (Fig 6). The excision was carded through subcutaneous tissue and platysma muscle and down to the inferior border of the mandible. The periosteum toward the center of the lesion was excised. The entire thickness of the tumor was elevated with a periosteal elevator. The mental nerve was in the center of the tumor and was sacrificed. The specimen was sent to the pathologist for frozen sections. A frozen section of the remaining stump of the mental nerve was also performed. The integrity of the mandibular bone was maintained, and there was no evidence of bony invasion because the tumor had not penetrated through the periosteum. The frozen sections showed the margins of the surgical specimen as well as the mental nerve stump to be free of tumor. The digastric muscle then was removed from the inferior border of the mandible and, in combination with the buccinator, used to close the periosteal defect and cover the mandibular bone. A rhomboid flap was then designed to locally reconstruct the surgical defect. Once the flap was reflected and mobilized, it was transposed into position with minimal tension. At 1 year postoperatively, the patient remained asymptomatic and free of detectable recurrence of the lesion. The surgical wound had healed uneventfully, and he had undergone minor scar revision and dermabrasion of the flap margins (Fig 7). He has now been free of tumor for 30 months.
MANDIBULAR DISTRACTION
J Oral Maxillofac Surg 53:838-846, 1995
Lengthening of the Mandible by Distraction Osteogenesis: Report of Cases ADI RACHMIEL, DMD,* MARK LEVY, MD, DSc,1- AND DOV LAUFER, DMD::I: Distraction osteogenesis is a technique of generating new bone by stretching the callus. This concept o f bone lengthening was first described by Codivilla in 1905,1 who used it to elongate a femur by repeated distraction forces. Other investigators also applied the technique, but it remained undeveloped because of associated complications such as nonunion, nerve damage, local edema, skin necrosis, and pin tract infection. 2'3 However, the technique of bone lengthening by gradual distraction was further developed and popularized by Ilizarov 4'5 in Russia and applied to the enchondral bones o f the upper and lower extremities. Lengthening o f the mandible 6-9 and midface 1° has been described in several animal studies. Recently McCarthy et al ~1described lengthening o f the human mandible by distraction osteogenesis using an extraoral a p p r o a ~ , The technique involves performing a cortic o t o m y on the buccal and lingual aspect o f the mandible, with preservation of the periosteum and the intramedullary blood supply. The distraction device is mounted on both sides of the corticotomy and a latency period of 5 to 10 days is allowed for primary callus organization. Then gradual distraction is performed at the rate o f 0.5 to 1.5 m m per day. After the desired lengthening has been achieved, a period of consolidation of a few weeks is suggested before removal o f the device. In this article we report lengthening o f the human mandible by gradual distraction using an intraoral approach for the corticotomy and an extraoral bone lengthening device.
dibular micrognathia underwent bilateral mandibular expansion. The patients ranged in age from 9 to 14 years. The procedure was performed under general anesthesia. An intraoral incision, 3 cm in length, was made over the external oblique line. Using a periosteal elevator, the buccal and lingual cortex was exposed in the lower portion of the mandibular ramus and the angle region. With a side cutting bur, horizontal buccal and lingual corticotomies were made in that part of the ramus below the entrance of the inferior alveolar nerve (Fig 1A). To complete a circumferential corticotomy, the cortex in the anterior and posterior part of the ramus was cut. A fiberoptic retractor was used to protect the periosteum and the inferior alveolar nerve while cutting. The expander device pins were placed in the p0~erior part of the ramus to avoid damage to the inferior alveolar nerve and to create a forward and downward vector of lengthening (Fig 1A). The pins were introduced transcutaneously through two small incisions 3 mm long. Once the end of the drill guide was exposed intraorally a self-retaining retractor hbld the clLeek tissue away from the end, allowing improved visualiza](i~n. Using a 1.5mm drill bit introduced through the drill guide sleeve, two holes were drilled at a distance of 10 and 14 mm, respec-
Report of Cases Two children with hemifacial microsomia underwent unilateral mandibular expansion, and one child with severe manReceived from the Department of Oral and Maxillofacial Surgery, Rambam Medical Center and the Technion Faculty of Medicine, Haifa, Israel. * Senior Consultant. t Resident. $ Professor and Head. Address correspondence and reprint requests to Dr Rachmiel: The Seldin Institute, Oral and Maxillofacial Surgery, Rambam Medical Center, Haifa 35 254, Israel. © 1995 American Association of Oral and Maxillofacial Surgeons 0278-2391/95/5307-001953.00/0
0 FIGURE 1. A, Diagram of the expansion device and the horizontal corticotomy in the inferior part of the ramus and B, oblique corticotomy in the genial region.
RACHMIEL, LEVY, AND LAUFER
FIGURE 2. A 9-year-old girl with severe micrognathia. A, Predistraction anteroposterior appearance. B, Predistraction profile view. C, Predistraction occlusion. Note the Class II relationship. D, Lateral cephalogram showing the severe mandibular micrognathia.
839
840
FIGURE 3. A, Patient at the beginning of lengthening with the expansion device bilaterally. B, A short pin was added (arrow) to produce forward lengthening of the mandible. C, View of patient after forward advancement of 22 ram. D, E, Patient after removal of the expansion device. (Continued next page)
MANDIBULAR DISTRACTION
RACHMIEL, LEVY, AND LAUFER
841
FIGURE 3. (Cont'd). F, G, Intraoral view of the occlusion. There is a slight tendency to an open bite.
tively, from the corticotomy (Fig 1A). Self-tapping pins were then inserted bicortically into the holes. These pins were 2 mm in diameter and 39 to 50 mm in length, according to the thickness of the cheek. Next a narrow osteotome was introduced to complete the corticotomy, following which a larger osteotome was used to produce slight movement between the two bony segments. Great care was taken not to damage the inferior alveolar nerve while executing this maneuver. When the major movement needed was forward, as in the case of severe micrognathia, the orientation of the corticotomy line was oblique toward the mandibular angle to keep the posterior part of the ramus intact (Fig 1B). The intraoral incision was closed with 3-0 Vicryl (Ethicon, Somerville, NJ) sutures, and the distraction apparatus was then attached to the pins extraorally. The patients received intravenous cephalosporin 50 mg&g per day for 5 days. After a latency period of 7 days, the device was lengthened 1 mm per day for 21 days by turning the bolt. Following the period of gradual distraction the device was used for retention for 7 additional weeks. In the patient with the severe micrognathia (Fig 2), after a lengthening of 5 mm, a short pin was added to the superior two interosseous pins of the device to change the direction of the lengthening and to produce a forward movement of the mandibular body (Figs 3 and 4).
Results A l l the surgical wounds healed uneventfully and there were no signs o f infection around the pins. The neurosensory integrity o f the inferior alveolar nerve, evaluated by touch discrimination, r e v e a l e d no sensory deficit in any o f the patients. In the two patients with hemifacial m i c r o s o m i a , a vertical lengthening in the ramus concomitant with a forward shift of m a n d i b l e was obtained (Figs 5 and 6). Intraorally there was m o v e m e n t o f the occlusion, with a shift to a Class I relation. Panoramic radiographs demonstrated elongation o f the rarnus after 21 days o f distraction (Fig 7 A and B). The e x p a n d e d area was filled with b o n e that was slightly less radiodense than the adjacent bone. A f t e r 7 additional weeks, the radiographs demonstrated increased radiodensity o f the bone (Fig 7C). The patient with severe micrognathia (Figs 2, 3, and 4) tended to d e v e l o p an open bite, which was corrected during the lengthening procedure by adding a pin to the device on both sides to change the direction o f
842
MANDIBULAR DISTRACTION
FIGURE 4. A, Panoramic radiograph of patient with the devices before commencement of forward lengthening. B, Cephalometric radiographs of the patient after bilateral 20 mm forward lengthening of the mandible. C, Panoramicradiographafter mandiblelengthening in the gonial region. The expanded area is filled with bone. lengthening (Fig 3B). A marked forward advancement of 22 m m was obtained. The patient needed additional orthodontic treatment for final adjustment of the occlusion. In all cases residual skin scars were noted in the p i n insertion points. After the device was removed there was no change in the occlusion.
Discussion Reconstruction of the severe hypoplastic mandible in young children is usually done with a costochondral
bone graft, followed by maxillomandibular fixation for several weeks. 1zI3 One of the drawbacks of a costochondral graft is the unpredictability of its growth, producing an excessive increase in mandibular length in some cases, an inadequate rate of growth in others, and in some cases no growth at all. 14-16Other complications with costochondral grafts are infection or resorption, 17 as well as the potential for such donor site morbidity as pneumothorax, scarring, a mild chest wall contour defect, and postoperative pain. 18 Lengthening of endochondral bones by distraction osteogenesis has been used successfully to achieve lengthening of the long bones of the extremities by up to 30 c m . 4'5 Previous animal studies have demonstrated that bone lengthening by gradual distraction is also applicable to membranous bones such as the mandible 69 and the maxilla. 1° Recently, it has been practiced successfully on the hypoplastic mandible of children with hemifacial microsomia and Nager syndrome. 11 The operation was performed through an extraoral approach. In our patients corticotomy was performed through a small intraoral incision, followed by subperiosteal tunneling, to preserve the periosteum and permit maxim u m osteogenic potential. The importance of an uninterrupted periosteal layer over the distracted area has been documented previously. 19'2° Only the cortex is osteotomized to preserve the medullary blood supply. 5 Although this preservation has been shown to optimize bone regeneration, other investigators 2°23 have demonstrated that preservation of the medullary blood supply is not absolutely necessary for success. To facilitate the lengthening, we placed an osteotome in the corticotomy to produce a slight movement between the two bony segments. Great care was taken not to separate completely the two segments, which could damage the inferior alveolar nerve. Another potential for nerve damage could be from pin insertion; therefore, the pins were placed in the posterior part of the mandibular ramus and angle, under direct intraoral visualization. It is known that craniofacial skeletal development is influenced by the functional matrix 24 so that mandibular growth occurs secondarily in response to demands of the attached neuromuscular system and functioning spaces. Enlow 25 also demonstrated that mandibular growth is dependent on the development of the masticatory muscles and eruption of the dentition. Ilizarov 5 reported that with bone distraction there is associate lengthening of the soft tissues, including muscles, nerves, and skin. It can therefore be concluded that mandibular lengthening by gradual distraction not only results in expansion of the jaw but also the attached muscles and soft tissues, with further influence on the expanded mandible. In an animal study 26 in which major midface ad-
RACHMIEL, LEVY, AND LAUFER
843
FIGURE 5. A 14-year-oldboy with right-sided hemifacial microsomia. A, Predistraction appearance. B, Predistraction occlusion. Note the Class II relationship. C, Panoramic radiograph showing the hypoplasia of the right mandibular ramus.
vancement was performed by gradual distraction (40 mm) there was only 7% relapse after 1 year. Histologic studies of the distracted membranous bone showed the formation of mature cortical b o n e . 8'27 This demonstrates that the expanded bone is of high quality and may have good long-term stability and potential for growth in children. Use of the sagittal split ramus osteotomy to correct mandibular retrognathism has been reported to involve a postsurgical neurosensory complication rate ranging from 0% to 5 4 % . 28 Block et a129 showed that distraction osteogenesis can be applied to the mandible with minimal neurosensory effect. The slow nerve stretching in distraction osteogenesis may result in minimal injury because less axonal tearing and less complete compression of the vasa nervorum occur. Young patients with a severely hypoplastic mandible especially benefit from this technique, which obviates the use of a bone graft with its possible complications and the need for maxillomandibular fixation. In hemifacial microsomia patients the vector of traction is vertical in the posterior part of the ramus. This permits an elongation of the short ramus and forward movement of the mandibular body, with correction of
the occlusion and achievement of symmetrical appearance. However, there is a versatility of lengthening direction by distraction osteogenesis. According to the desired direction of mandibular movement, it is possible to place the corticotomy in different sites and orientations such as horizontal in the ramus for hemifacial microsomia or oblique in the angle for both vertical lengthening of the ramus and forward advancement of the mandible. During the gradual distraction there is the possibility of changing the direction of lengthening by making simple changes on the apparatus. In the patient with severe micrognathia the vector of elongation was forward and downward followed by major forward advancement of the mandible. To overcome the tendency of open bite, the simple adding of a pin to the device can change the direction of lengthening in the desired vector. One of the drawbacks of distraction of bone by an extraoral approach are the residual skin scars on the cheek.H To minimize these problems an intraoral approach was used for the corticotomy, and two small incisions were used for pin insertion. Another drawback of an extraoral approach is the potential for dam-
844
MANDIBULAR DISTRACTION
FIGURE 6. A, Patient immediately after surgery with the expansion device. B, View of patient after a 20 mm distraction~ C, The patient after removal of the expansion device. The mandible is more symmetrical and the midpoint of the chin has moved medially. D, Intraoral view of the occlusion. Note the change to a Class I relationship.
845
RACHMIEL, LEVY, AND LAUFER
FIGURE 7. A, The panoramic radiographs of the patient in Figure 6. Device before commencement of distraction. Note the corticotomy (arrow). The unerupted third molar was extracted. B, Completion of ramus distraction. The expanded area is filled with bone (between arrows). C, The elongated ramus after removal of the device.
age to the m a n d i b u l a r branch o f the facial nerve. De. device 30 m a y offer the veloping an intraoral distraction advantages o f an extraoral device without the need for a cutaneous incision and resulting scar. •
Acknowledgment
13. 14. 15.
The authors thank Howmedica lnc, Rutherford, NJ for their generous help in providing the distraction apparatus.
16.
References
17.
1. Codivilla A: On the means of lengthening in the lower limbs, muscles and tissues which are shortened through deformity. Am J Orthop Surg 2:353, 1905 2. Abbott LC: The operative lengthening of the tibia and fibula. J Bone Joint Surg [Br] 9:128, 1927 3. Abbott LC, Saunders JB: The operative lengthening of the tibia and fibula: A preliminary report in the further development of principles and technique. Ann Surg 110:961, 1939 4. Ilizarov GA: The principles of the Ilizarov method. Bull Hosp Jt Dis Orthop Inst 48:1, 1988 5. Ilizarov GA, Devyatov AA, Karnerim VK: Plastic reconstruction of longitudinal bone defects by means of compression and subsequent distraction. Acta Chir Plast 22:32, 1980 6. Snyder CC, Levine GA, Swanson HM, et al: Mandibular lengthening by gradual distraction. Plast Reconstr Surg 51:506, 1973 7. Michieli S, Miotti B: Lengthening of mandibular body by gradua~ surgical-orthodontic distraction. J Oral Surg. 35:187, 1977 8. Karp NS, Thorne CHM, McCarthy JG, et al: Bone lengthening in the craniofacial skeleton. Ann Plast Snrg 24:231, 1990 9. Karaharju T, Karaharju EO, Ranta R: Mandibular distraction: An experimental study on sheep. J Craniomaxillofac Surg 18:280, 1990 10. Rachmiel A, Potparic Z, Jackson IT, et al: Midface advancement by gradual distraction. Br J Plast Surg 46:201, 1993 11. McCarthy JG, Schreiber J, Karp N, et al: Lengthening of mandible by gradual distraction. Plast Reconstr Surg 89:1, 1992 12. Kaban LB, Moses MH, Mulliken JB: Surgical correction of
18.
19.
20.
21.
22.
23.
24. 25. 26.
hemifacial microsomia in the growing child. Plast Reconstr Surg 82:9, 1988 Mulliken JB, Kaban LB: Analysis and treatment of hemifacial microsomia in childhood. Clin Plast Surg 14:91, 1987 McIntosh RB, Henny FA: A spectrum of application of autogenous costochondral grafts. J Maxillofac Surg 5:257, 1977 Politics C, Fossion E, Bossuyt M: The use of eostochondral graft in arthroplasty of the temporomandibular joint. J Craniomaxillofac Surg 15:345, 1987 Munro IR, Philips JH, Griffin G: Growth and construction of the temporomandibular joint in children with hemifacial microsomia. Cleft ]Palate J 26:303, 1989 Mclntosh RB: Cun:ent spectrum of costochondral grafting, in Bell WH (ed): Surgical Correction of Dentofacial Deformities: New concepts, vol 3. Philadelphia, PA, Saunders, 1985, pp 355-410 Laurie SW, Kaban LB, Mulliken JB, et al: Donor site morbidity after harvesting rib and iliac bone. Plast Reconstr Surg 73:933, 1984 Kojimoto H, Yasui N, Goto T, et al: Bone lengthening in rabbits by callus distraction: The role of periosteum and endosteum. J Bone Joint Surg [Br] 70:543, 1988 Delloye C, Delefortrie G, Coutelier L, et al: Bone regenerate formation in cortical bone during distraction lengthening: An experimental study. Clin Orthop 250:34, 1990 DeBastiani G, Oldegheri R, Ranzi-Brivio L, et al: Limb lengthening by callus distraction (callostasis). J Pediatr Orthop 7:129, 1987 Constantino PD, Shybut G, Friedman CD, et al: Segmental mandibular regeneration by distraction osteogenesis. Arch Otolaryngol Head Neck Surg 116:535, 1990 Phillips JH, Forrest CR, Gruss JS: Current concepts in the use of bone grafts in facial fractures. Clin Plast Surg 19:41, 1992 Moss ML, Rankow RM: The role of functional matrix in mandibular growth, Angle Orthod 38:93, 1968 Enlow DH: Handbook of Facial Growth (ed 2). Philadelphia, PA, Saunders, 1982 Rachmiel A, Jackson IT, Clayman L, et al: Midface advancement by gradual distraction: A follow-up study. Presented at V International Congress of Craniofacial Surgery, Oaxaca, Mexico, October 1993
846
MICROCYSTIC ADNEXAL CARCINOMA
27. Karp NS, McCarthy JG, Schreiber JS, et al: Membranous bone lengthening:A serial histological study. Ann Plast Surg 29:2, 1992 28. Karns P, Nester D, Boyd C, et al: Recovery of neurosensory function following orthognathic surgery. J Oral Maxillofac Surg 48:124, 1990 29. 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 51:652, 1993 30. StaffenbergDA, Wood JR, McCarthy JG: Mandibularlengthening in the canine using an intraoral device. Presented at V International Congress of Craniofacial Surgery, Oaxaca, Mexico, October 1993
J Oral Maxillofac Surg 53:846-849, 1995
Microcystic Adnexal Carcinoma: Report of a Case MICHAEL L. ROBINSON, MD, DMD,* MARK A. KNIBBE, MD, DDS,* AND JOHN B. ROBERSON, DMD~f Microcystic adnexal carcinoma (MAC) is a recently described n e o p l a s m with c o m b i n e d pilar and eccrine differentiation that is characterized by a locally aggressive growth pattern. ~ Wallace and Bernstein2 reported that M A C occurs primarily on the faces of y o u n g and middle-aged w o m e n ; however Borenstein et al 3 state that males and females are affected equally. This entity can be clinically and histologically confused with other malignant and b e n i g n cutaneous neoplasms, which may lead to inadequate initial treatment and extensive recurrence. 4 W e present a case of M A C in a middleaged m a n who received radiation therapy as an adolescent for the treatment of acne.
Report of Case A 53-year-old white man was evaluated in our office after visiting his dermatologist and general dentist. The patient had a cutaneous lesion in the left mental region for approximately 2-years. The lesion was 4 x 4 cm in size and had irregular margins. It was nontender and had an erythematous cutaneous surface (Figs 1, 2). The patient's medical history was essentially negative, although he did receive radiation treatment for acne as an adolescent. The social history was negative for tobacco and alcohol abuse. An incisional biopsy was performed under local anesthesia in the office on July 31, 1992. Microscopic examination of
* In .private practice, Oral and Maxillofacial Surgery, Edgewood, KY. "~Resident, Oral and MaxillofacialSurgery, University of Cincinnati, Cincinnati, OH. Address correspondence and reprint requests to Dr Knibbe: 20 Medical Village Dr, Suite 196, Edgewood, KY 41017. © 1995 American Association of Oral and Maxillofacial Surgeons 0278-2391/95/5307-002053.00/0
the specimen showed stratified squamous epithelium, pilesebaceous structures, supporting connective tissue, and an adnexal neoplasm (Fig 3). Within the superficial connective tissue were numerous microcysts that were filled with a keratinlike material (Fig 4). There were several layers of flattened cuboidal cells lining the microcysts. The individual microcysts were not well delineated and extended into the underlying connective tissue. The tumor was infiltrating between muscle fibers and approached segments of peripheral nerve (Fig 5). The histologic findings were consistent with a diagnosis of MAC. One week later the patient was taken to the operating room for removal of the lesion and immediate reconstruction. The lesion was marked with 1-cm margins from the palpable tumor. The planned excision encompassed an area measuring 6.5 cm anteroposterior and 6 cm superoinferiorly (Fig 6). The excision was carded through subcutaneous tissue and platysma muscle and down to the inferior border of the mandible. The periosteum toward the center of the lesion was excised. The entire thickness of the tumor was elevated with a periosteal elevator. The mental nerve was in the center of the tumor and was sacrificed. The specimen was sent to the pathologist for frozen sections. A frozen section of the remaining stump of the mental nerve was also performed. The integrity of the mandibular bone was maintained, and there was no evidence of bony invasion because the tumor had not penetrated through the periosteum. The frozen sections showed the margins of the surgical specimen as well as the mental nerve stump to be free of tumor. The digastric muscle then was removed from the inferior border of the mandible and, in combination with the buccinator, used to close the periosteal defect and cover the mandibular bone. A rhomboid flap was then designed to locally reconstruct the surgical defect. Once the flap was reflected and mobilized, it was transposed into position with minimal tension. At 1 year postoperatively, the patient remained asymptomatic and free of detectable recurrence of the lesion. The surgical wound had healed uneventfully, and he had undergone minor scar revision and dermabrasion of the flap margins (Fig 7). He has now been free of tumor for 30 months.