Transcervical Removal of an Impacted Third Molar: An Uncommon Indication Yash K. Singh, BDS, DMD, MD,* Arthur K. Adamo, DDS,y Niral Parikh, DDS, BDS,z and Daniel Buchbinder, DMD, MDx This article presents a case of and reviews the literature involving the extraoral approach for surgical removal of an ectopic mandibular third molar tooth. Case reports describing extraction of the mandibular third molar using the extraoral approach are very limited. This article describes an unusual case of an impacted, infected, ectopic right mandibular third molar that was positioned at the inferior border and had caused an extraoral draining sinus. Furthermore, the roots were intimately involved with the inferior alveolar nerve (IAN) and had perforated the buccal cortex of the mandible. Surgical removal using a transcervical submandibular approach was deemed necessary to try to preserve the IAN and avoid fracture of the mandible in this 74-year-old patient. Ó 2014 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 72:470-473, 2014 notch, and the angle of mandible.4,5 Most ectopic third molar teeth have been reported in the condyle, subcondylar, or high ramus region. Management of ectopic impacted teeth depends on the symptoms of the patient and any associated pathology. Usually, these teeth are an incidental finding on a radiograph and may not require surgical treatment unless they are symptomatic or have associated pathology.4 Extraoral, intraoral, and endoscopic surgical approaches have been used successfully.4-7 Demographic factors, such as age, gender, or ethnicity, have a minimal role in the difficulty of third molar extractions.8 Common complications of third molar surgery include secondary infection, hemorrhage, alveolar osteitis, and nerve dysfunction. Mandibular angle fracture is an uncommon complication. Risk factors include the depth of tooth impaction, tooth angulation, root length, the patient’s age, experience of the surgeon, presence of cysts or tumors, systemic disease, medications that can impair bone strength, and preoperative infection in the third molar site.9
The incidence of mandibular third molar impaction has been reported as 20 to 30% of the population, with women being affected more than men.1 The mandibular third molar also is the most commonly impacted tooth, followed by maxillary third molars and maxillary canines.2 According to a White Paper published in 2011 by the American Association of Oral and Maxillofacial Surgeons,3 impacted third molars should be removed, even if asymptomatic, if there is reasonable potential for pathology. There is a higher incidence of nerve injury in older patients, when the roots are fully developed and in proximity to the inferior alveolar nerve (IAN). There also is a decrease in nerve regeneration in older patients.3 When the mandibular third molar is grossly displaced from its normal position to the lower border of the mandible or high up into the ascending ramus, it can be referred to as ectopic.4 Cases of mandibular third molars have been reported in the literature as being displaced into the mandibular condyle, ascending ramus, coronoid process, sigmoid
*Chief Resident, Beth Israel/Jacobi Medical Center/Albert
Address correspondence and reprint requests to Dr Singh: Beth
Einstein College of Medicine, Philip Ambulatory Care Center, New
Israel/Jacobi Medical Center/Albert Einstein College of Medicine,
Philip Ambulatory Care Center, 10 Union Square, Suite 5B, New
yDirector Emeritus, Department of Oral and Maxillofacial Surgery,
York, NY 10003; e-mail: [email protected]
North Bronx Healthcare Network, New York, NY.
Received April 25 2013
zFormer Chief Resident, Beth Israel/Jacobi Medical Center/Albert
Accepted September 17 2013 Ó 2014 American Association of Oral and Maxillofacial Surgeons
Einstein College of Medicine, New York, NY; Currently, Private Practice, Valley Oral Surgery, PC, Allentown, PA.
xDirector, Oral and Maxillofacial Surgery Residency Program,
Beth Israel/Jacobi Medical Center/Albert Einstein College of Medicine, New York, NY.
SINGH ET AL
Report of Case A 74-year-old woman was referred to the oral and maxillofacial surgery clinic by an oral and maxillofacial surgeon. Her chief complaint was intermittent pain in the right posterior mandible for over a year. Pain would occur when the patient opened her mouth widely. Her medical history included hypertension, hyperlipidemia, and a hysterectomy many years ago. On physical examination, there was no tenderness to palpation in the area of the lower right third molar, but there was mild tenderness intraorally in the muscles of mastication. Panorex radiograph (Fig 1) showed coronal and periapical radiolucency and an intimate relation of the IAN to the impacted right mandibular third molar. Cone-beam computed tomographic (CT) image (i-CAT; Imaging Sciences International, LLC, Hatfield, PA) visualized the IAN passing between the roots of the lower right third molar. The decision was made to observe the patient periodically because she had only mild discomfort and was reluctant to have the necessary surgery. The patient presented 1 month later with a new complaint of paresthesia of the right lip and chin. The possibility that the periapical pathology had invaded the IAN was a concern. CT scan of the mandible with intravenous (IV) contrast was ordered at this time to rule out any primary or metastatic malignant lesion of the mandible. The scan showed that the apices of the lower right third molar had perforated the buccal cortex. There was no evidence of enhancing tumor at the site. The patient was informed about the
CT findings, but did not want any surgical intervention at that time. It was stressed that if her symptoms deteriorated or she developed an infection, she would have to undergo surgical removal of the tooth. She also understood that there was a risk of mandibular fracture. Three months later the patient returned with pain, swelling, and an extraoral draining sinus tract (Fig 2). In view of the current signs and symptoms, she agreed to undergo surgical removal of the lower right third molar. The acute infection was treated by performing an extraoral incision and drainage (I&D) and the insertion of a Penrose drain under IV sedation in the outpatient oral surgery clinic. She also was given IV clindamycin. Because the initial panoramic view showed this third molar with more than a third of the roots inferior to the mandibular canal, removal by a sagittal split osteotomy or a transcervical approach was considered. However, because of the intimate relation of the IAN to the roots of the lower right third molar and the possibility of a poor split in this 74-year-old patient, the transcervical approach was selected. The patient’s age and the difficulty of the surgery also predisposed her to sustaining jaw fracture during the surgery or postoperatively.9 To prevent this, it was planned that a titanium plate would be placed and this would be easier from the extraoral approach. The tooth was surgically removed using the Risdon extraoral approach. The incision was made inferior to the previous I&D incision and 1.5 cm below the mandibular border. The facial artery and vein were identified and ligated. The dissection was carried down to the pterygomasseteric sling, which was
FIGURE 1. Panorex radiograph shows impacted lower right third molar with periapical radiolucency. Singh et al. Transcervical Removal of Impacted Third Molar. J Oral Maxillofac Surg 2014.
TRANSCERVICAL REMOVAL OF IMPACTED THIRD MOLAR
FIGURE 2. Swelling in the right angle region and purulent discharge. Singh et al. Transcervical Removal of Impacted Third Molar. J Oral Maxillofac Surg 2014.
incised, and the masseter muscle was reflected off the lateral surface of the mandible. The perforation of the buccal cortex by the roots of the lower right third molar was visualized. A buccal corticotomy was performed for wider exposure of the impaction. Then, the tooth was sectioned and surgically removed, preserving the IAN. As a precaution, a 2-mm titanium plate (Synthes, Inc, West Chester, PA) was placed to reinforce the mandible and to avoid a potential postoperative fracture. The 2 central screws were not placed because they would have been in the defect created when the impaction was removed. The extreme screw on the proximal segment was placed in a monocortical fashion to avoid possible IAN injury (Fig 3).
The surgical defect was filled with a bone morphogenic protein–impregnated sponge to promote bone healing. Then, the surgical wound was closed in layers and a Penrose drain was placed. The extracted tooth and the periapical and pericoronal tissues were sent for histologic examination, which indicated a dentigerous cyst for the coronal lesion and a periapical cyst with chronic inflammation for the periapical lesion. The immediate postoperative Panorex radiograph confirmed that a fracture had not occurred and there was minimal bone support in the angle region. Two weeks postoperatively, the incision was healing well without facial nerve deficit. The patient continued to have some IAN paresthesia with mild improvement. At her 6-month follow-up visit, the patient showed significant improvement of the IAN paresthesia and adequate bone healing of the extraction site. The intraoral surgical site had healed completely and there was no facial nerve weakness. After 1 year, the patient had minimal hypoesthesia of the lip and chin. The surgical site had healed well without any facial nerve deficit. Panoramic radiograph taken after 1 year showed complete bony fill of the defect (Fig 3).
Discussion The presence of an ectopic third molar located in different parts of the mandible has been reported, but it is encountered infrequently. Most of these impactions have been found in the condylar region. The ectopic lower third molar close to the inferior border
FIGURE 3. Panorex radiograph 1 year after surgery shows complete bone fill. Singh et al. Transcervical Removal of Impacted Third Molar. J Oral Maxillofac Surg 2014.
SINGH ET AL
of the mandible is less common. The present case is a rare case in the operative experience of the senior surgeon and this is the first time in his career of at least 40 years that an extraoral approach was used for the surgical removal of an impacted mandibular third molar. Usually, ectopic third molars are found as an incidental finding on routine radiographs. They usually can be observed and periodically followed unless there is associated pathology or the patient becomes symptomatic. Intraoral and extraoral approaches have been described in the literature, including sagittal split osteotomy and an endoscopic approach. The extraoral approach allows for good exposure of the lateral and inferior borders of the mandible, but the surgeon must consider possible damage to the facial nerve and the surgical scar. The reported case is an uncommon indication for the extraoral approach. Acknowledgments The authors thank Dr David Sheinkopf, attending oral and maxillofacial surgeon at their hospital, for referring this patient to their center and for critically reviewing this report before submission for publication.
References 1. Andreasen JO, Petersen JK, Laskin DM: Textbook and Color Atlas of Tooth Impaction—Diagnosis, Treatment and Prevention. St Louis, MO, Mosby Yearbook, 1997 2. Peterson LJ, Ellis E, Hupp JR, Tucker MR: Principles of management of impacted teeth, in Contemporary Oral and Maxillofacial Surgery (ed 4). St. Louis, Missouri: Mosby p 184–213 3. White Paper on evidence-based third molar surgery. Presented at: Annual Meeting of the American Association of Oral and Maxillofacial Surgeons; Philadelphia, PA, November 2011 4. Ahmed NM, Speculand B: Removal of ectopic mandibular third molar teeth: Literature review and a report of three cases. J Oral Surg 5:39, 2012 5. Shivashankara C, Manjunatha BS, Tanveer A: Ectopic mandibular third molar in subcondylar region: Report of a rare case. J Oral Maxillofac Surg 16:153, 2012 6. Procacci P, Albanese M, Sancassani G, et al: Ectopic mandibular third molar: Report of two cases by intraoral and extraoral access. Minerva Stomatol 60:383, 2011 7. Wang CC, Kok SH, Hou LT, et al: Ectopic mandibular third molar in the ramus region: Report of a case and literature review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 105: 155, 2008 8. Susarla SM, Dodson TB: Risk factors for third molar extraction difficulty. J Oral Maxillofac Surg 62:1363, 2004 9. Chrcanovic BR, Cust odio AL: Considerations of mandibular angle fractures during and after surgery for removal of third molars: A review of the literature. J Oral Maxillofac Surg 14:71, 2010