179 182 Surgical Management of a Large, Complex Mandibular Odontoma by Unilateral Sagittal Split Osteotomy

7/30/2019 179 182 Surgical Management of a Large, Complex Mandibular Odontoma by Unilateral Sagittal Split Osteotomy

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GORDON B. WONG

ReferencesI. BumstedWD: Cylindroma of the mandible. Oral Surg 8:546,19552. Bradley JC: A case of cylindroma ofthe mandible. Br J OralSurg 5:186,1%83. Dhawan IK, Bhargava S, Nayak NG, et al: Central salivarygland tumors of jaws. Cancer 26:211, 19704. Slavin G, Mitchell RM: Adenoid cystic carcinoma of themandible. Br J Surg 58:546, 19715. Yoshimura Y, Hasega K, Wada T, et al: Metastasis of adenoid cystic carcinoma of the mandible to the gasserianganglion. J Am Dent Assoc 94:469, 19786. Mushimoto K, Hashimoto Y, Tabuchi M, et al : Central adenoid cystic carcinoma of the mandible: Report of a case.Jpn J Oral Surg 24:973, 19787. Kaneda T, Mizuno N, Takeuchi M, et al: Primary centraladenoid cystic carcinoma of the mandible. J Oral Maxillofac Surg 40:741, 19828. Bhaskar SN, Bernier JL: Mucoepidermoid tumors of major.and minor salivary glands (144 cases). Cancer 15:801,1%29. Alexander RW: Central mucoepidermoid tumor of the mandible. J Oral Surg 32:541,197410. Browand BC: Central mucoepidermoid tumors of the jaws:

J Oral Maxillofac Surg47:179-182.1989

179Report of nine cases and review of the li terature. OralSurg 40:631, 1975I I. Perzin KH, Gullane P, Clairmont AG: Adenoid cystic carcinomas arising in salivary glands: A correlation of histologic features and clinical course. Cancer 42:265, 197812. Simpson JR, ThawleySE , Matsuba HM:Adenoid cystic carcinoma: Treatment with irradiation and surgery. Radiology 151:509, 1984

13. Antonio G, Ana LP, Lygia AF, et al : Adenoid cystic carcinoma of salivary glands: A study of 61 cases with clinicopathologic correlation. Cancer 57:312, 198614. Matsba HM, Gershon J, Stanley E, et al: Adenoid cyst icsalivary gland carcinoma: A histopathologic review oftreatment failure patterns. Cancer 57:519, 198615. Rentschler R, Burgess MA, Byers R: Chemotherapy of malignant major salivary gland neoplasms. Cancer 40:619,197716. Vermeer RJ, Pinedo HM: Partial remission of advanced adenoid cystic carcinoma obtained with adriamycin. Cancer43:1604, 197917. Belson TP, Toohill RJ, Lehman RH, et al: Adenoid cysticcarcinoma of the submaxillary gland. Laryngoscope92:497, 198218. Gates GA: Current concepts in otolaryngology: Malignantneoplasms of the minor salivary glands. N Engl J Med306:718, 1982

Surgical Management of a Large,Complex Mandibular Odontoma byUnilateral Sagittal Split OsteotomyGORDON B. WONG, MSc, DDS*

IntroductionOdontomas are the most common odontogenictumors when the classification has been restrictedto only those mixed lesions containing fully formeddental tissues of both epithelial and mesenchymalorigin. t The complex odontoma consists of a mass

of irregularly arranged enamel, dentine, cementum,and connective tissue. The compound odontomaconsists of a collection of small, morphologicallyrecognizable teeth in the tissue mass. Although theypossess limited growth potential, quite large dimen-

In private practice, Oral and Maxillofacial Surgery, Sault SteMarie, Ontario, Canada.Address correspondence and reprint requests to DrWong: 350Queen St E, Sault Ste Marie, Ontario P6A IZI, Canada. 1989American Association of Oral and Maxillofacial Sur-geons02782391/8914702-0012$3.00/0

sions can be attained during the active growth period.Rittersma and Van Goof initially described theuse of sagittal splitting of the mandible to gain access for enucleation of a large, multinucleated keratocyst, thereby avoiding the increased morbidity associated with resection and bone grafting of a nonmalignant lesion. A similar approach has recentlybeen described by Petti et al3 for the resection of amandibular myxoma with good results. When largecomplex odontomas have occurred in the mandibular angle and ramus region, two recent successfulcases of removal after sagittal splitting of the mandible have been reported.Y This report describes asimilar case of a large, complex odontoma of themandible treated by a complete splitting of the ramus through the inferior border.

Report of a CaseA healthy 13-year-old white boy was referred by hisfamily dentist in December 1986for evaluation regarding


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180 SAGITIAL SPLITOSTEOTOMY FOR ODONTOMA

FIGURE 1. Panoramic radiograph demonstrating a large, radiopaque lesion of the rightmandibular ramus and anglearea, with an inferiorly displaced, unerupted lower secondmolar.

an unerupted lower-right second molar. The patient wasasymptomatic and was not aware of any swelling or discomfort in his jaw. Clinical examination did not revealany extraoral facial swelling or asymmetry, and there wasnormal sensation in the distribution of the right mentalnerve. He had a full complement of permanent teeth except for the absence of the lower-right second molar.There was only minimal evidence of buccal or lingualcortical expansion of the mandible. A panoramic radiograph revealed a 2.5-cm diameter radiopaque mass in theright mandibular ramus and angle region with anunerupted lower-right second molar displaced anteriorlyand inferiorly at the lower border of the mandible (Fig I) .The lesion was surrounded by a thin radiolucent zone.The lower-right third molar was missing, and the mandibular nerve canal was displaced inferiorly. Submental vertex and postero-anterior mandible views showed minimalbony expansion of the buccal and lingual cortices (Fig 2).The density of the mass and the uniform soft tissue capsule were compatible with a diagnosis of a complexodontoma.It was elected to excise the tumor by a sagittal splitosteotomy because this would not only provide adequatesurgical access to the lesion, but would also preserve thebuccal and lingual cortices. In March 1987, under hypotensive general anesthesia administered via nasoendotracheal intubation, Ivy loops were placed on the premola r teeth in each quadrant. A standard intraoral buccalvestibular incision was made along the external obliqueridge from the right mandibular ramus to the mesial of thefirst molar. A subperiosteal dissection exposed the anterior border of the ramus, the coronoid process , and themedial aspect of the ramus above the lingula. The usualhorizontal osteotomy was made through the medial cortical plate of the ramus, extended along the anterior border of the ramus, and passed vertically through the buccalcortex of the mandibular body at the distal aspect of thefirst molar. The mass was noted to have expanded boththe buccal and lingual cortices, and the osteotomy incision along the anter ior border of the ramus passed directly through the superior aspect of the tumor. The mass

was bony-hard, of uniform density, and yellowish incolor.Using fine burs and osteotomes, the sagittal split wascompleted, deep through the tumor mass to the inferiorborder of the mandible. A satisfactory split was achieved.The inferior alveolar nerve was not visualized. The lateral

FIGURE 2. Submental vertex radiograph of the mandibleshowing some minimal buccal and lingual corticalexpansion.


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GORDON B. WONG 181

FIGURE 3. Panoramic radiograph immediately postoperatively, showing excision of thetumor mass a long with theunerupted lower second molar.Note the superior border wirefixation.

portion of the mass was enucleated from the inner aspectof the proximal segment, and the greater majority of themass within the distal tooth-bearing segment was removed in multiple fragments by sectioning. All specimenswere submitted fo r histologic examinat ion. Theunerupted lower-right second molar was visualized andremoved in the usual fashion. A 2S-gauge stainless steelwire was passed through the superior borders of the proximal and distal segments. The wound was then thoroughlyirrigated with bacitracin solution and maxillomandibularfixation was applied using 25-gauge stainless steel wiresligated to the Ivy loops. Gelfoamv (Upiohn, Kalamazoo,MI) was placed into the remaining bony cavity and theintraosseous wire was tightened while the proximal segment was positioned posteriorly and superiorly in the glenoid fossa. The wound was closed in one layer using Vicryl (Ethicon, Peterborough, Ontario)sutures. The patienthad an uneventful postoperative course and was discharged two days later. There was evidence of mild rightmental nerve paresthesia postsurgically. A postoperativepanoramic radiograph showed excellent bony alignment(Fig 3). Fixation was released at 6 weeks. The histologicexamination showed a haphazard arrangement of enamel,

enamel organ, dentine, cementum, and dental pulp, consistent with a diagnosis of complex odontoma. At the12month follow-up visit , there was evidence of goodbony regeneration in the area of the excised tumor (Fig 4),along with a stable occlusion. There was mild residualparesthesia localized to the right vermilion border of thelower lip.Discussion

The advantages of a sagittal split osteotomy togain access for the removal of a large benign lesionof the mandible in a young person outweigh those ofthe convent iona l b lock resection technique. I tavoids the formation of a large defect in the corticalbone with its associated increased risk of fracture.It prevents the need for autogenous bone grafting ofa nonmalignant lesion in a young patient, along withits associated morbidity. Excellent access to the lesion is achieved, especially when the lesion lies entirely within the cortical plates, and the continuity

FIGURE 4. Panoramic radiograph 12 months postopera-tively, showing excellent bonyregeneration in the area of theexcised odontoma and secondmolar.


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182of the mandible is preserved after fixation of theproximal and distal fragments. The ability to dissectand preserve the neurovascular bundle, especiallywhen it has been displaced by a lesion, is a decidedadvantage over other resection techniques wherethe nerve would most likely have to be sacrificed.The major potential complication of this ap-proach would be fracture of the buccal, corticalbone as alluded to by Frame." However, his caseinvolved an older patient with extreme thinning ofthe buccal cortex. He performed a modification of

the sag ittal split osteotomy as suggested byBarnard," in which a buccal, instead of a lingual,horizontal osteotomywas made inorder to preservethe bony continuity of the mandible. Barnard" didnot perform a complete separation of the proximaland distal segments, but did mention a greenstickfracture of the buccal cortical bone. In the presentcase, the surgical management of a similar large,

SAGITTAL SPLIT OSTEOTOMY FOR ODONTOMA

complex odontoma of the mandible was accom-plished by performing a complete sagittal splitthrough the inferior border. The possible complica-tions of buccal cortical fracture by torquing of seg-ments to gain access through the superior aspect ofthe split were thus avoided.References

I. Lucas RB: Pathology of Tumours of the Oral Tissues (ed 3).Edinburgh, Churchill, Livingston, 19762. Rittersma J, Van Gool AV: Surgical access to multicysticlesions by sagittal splitting of the lower jaw. J MaxillofacSurg 7:246, 19793. Petti NA, Weber FL, MillerMC: Resection of a mandibularmyxoma via a sagittal ramus osteotomy. J Oral MaxillofacSurg 45:793, 19874. Barnard D: Surgical access to a complex composite odon-tome by sagittal splitting of the mandible. Br J Oral Surg21:44,19835. Frame JW: Surgical excision of a large complex compositeodontome of the mandible. Br J Oral Maxillofac Surg24:47, 1986

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179 182 Surgical Management of a Large, Complex Mandibular Odontoma by Unilateral Sagittal Split Osteotomy