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Late Mandibular Fracture After Lower Third Molar Extraction in a Patient With Stafne Bone Cavity: A Case Report
1698
LATE MANDIBULAR FRACTURE AFTER MOLAR EXTRACTION
J Oral Maxillofac Surg 68:1698-1700, 2010
Late Mandibular Fracture After Lower Third Molar Extraction in a Patient With Stafne Bone Cavity: A Case Report Yu-Hsun Kao, DDS, MS,* I-Yueh Eric Huang, DDS, MS,† Chao-Ming Chen, DDS,‡ Chun-Wei Wu, DDS, MS,§ Kun-Jung Hsu, DDS,储 and Chun-Min Chen, DDS, MS¶ Surgical removal of the mandibular third molar is a common surgical procedure in dental clinics. Complications may include infection, bleeding, nerve injury, trismus, and accidentally displaced lower third molar,1 but the late fracture of mandible is very rare.2-6 Stafne cyst was first reported by Stafne in 1942 to describe the bone cavity in the angle of the mandible.7 However, Stafne cyst is not a true cyst, and some articles have suggested that the Stafne bony cavity be renamed.8,9 The purpose of this report is to present an unusual case of late mandibular fracture after extraction of a lower third molar in a patient with Stafne bone cavity. To our knowledge, this is the first case report in the English-language literature of these 2 rare conditions in 1 patient.
Report of a Case A 54-year-old Japanese man presented to our clinic with a change of occlusion and swelling at the left mandibular angle area. We reviewed the patient’s history of dental treatment and found that he had had swelling over the left lower third molar area for approximately 1 week and had visited a local dental clinic on October 18, 2007. The dentist took a periapical film, and a left mesio-angulately impacted
Received from Kaohsiung Medical University, Kaohsiung, Taiwan. *Clinical Instructor, Department of Dentistry. †Associate Professor, Department of Oral and Maxillofacial Surgery, and Department of Dentistry. ‡Clinical Instructor, Department of Dentistry. §Clinical Instructor, Department of Dentistry. 储Clinical Instructor, Department of Dentistry. ¶Associate Professor, Department of Dentistry. Address correspondence and reprint requests to Dr Huang: Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung, Taiwan; e-mail: [email protected] © 2010 American Association of Oral and Maxillofacial Surgeons
0278-2391/10/6807-0040$36.00/0 doi:10.1016/j.joms.2009.06.019
third molar with pericoronitis was suspected but cast no radiolucent shadow on the film. The dentist gave him antibiotics and local anesthesia. After acute infection subsided, the dentist extracted the third molar on November 19, 2007. The wound healed uneventfully until the patient experienced a clear clicking sound while eating foods by mid-February 2008, more than 6 weeks after extraction. A few days later, swelling over his left mandibular angle led him to visit his dentist again on February 18, 2008. After taking a Panorex that showed fracture over the left mandibular angle and a radiolucent lesion at the lower border of the mandible, the dentist referred the patient to our department for further evaluation and treatment. However, the patient did not present to our clinic until March 28, 2008, approximately 6 weeks after the fracture. Before this extraction, the patient was a healthy man and had had regular dental examinations; he did not feel any discomfort over the left mandibular angle area. We examined the patient and found tenderness, swelling, and local heat indicating infection over the left mandibular angle; in addition, the patient’s left lower lip was numb and he could not bite to his central occlusion. Panoramic radiography showed a socket of mesio-angulately impacted third molar and a radiolucent shadow with sclerotic cortical margin at the mandibular angle, with the mandibular canal passing through the radiolucent area (Fig 1) We checked the patient’s computed tomography (CT) scan (Fig 2) and, because the report indicated malignancy due to the irregu-
FIGURE 1. Panorex showing the socket of the left lower third molar, a radiolucent lesion with sclerotic margin below the third molar and above the mandibular lower border, with the mandibular canal passing through the lesion. The fracture line is from the socket to the antegonial notch. Kao et al. Late Mandibular Fracture After Molar Extraction. J Oral Maxillofac Surg 2010.
1699
KAO ET AL lar border of the lesion, we suggested a biopsy. After discussion with the patient, we decided to take a biopsy sample from the submandibular area for the radiolucent lesion and to perform open reduction with internal fixation for the mandibular fracture. Because the patient was busy, the operation was arranged for May 2008, about 3 months after the fracture occurred. Because the patient refused a temporary fixation, he was advised to consume a soft diet. Surgery was performed on May 16, 2008, under general anesthesia with an endotracheal tube. A submandibular incision was made and blunt dissection exposed the frac-
FIGURE 3. Photograph showing the healed fracture line (small upward arrow) and the depression of the bony cavity (large upward arrow). Kao et al. Late Mandibular Fracture After Molar Extraction. J Oral Maxillofac Surg 2010.
ture and bony cavity. We found that the fractured bone had healed (Fig 3) and the occlusion was stable, so we did not perform reduction and fixation. The bony cavity was filled with soft tissue, which was removed for pathological examination; after this procedure, we found that the inferior alveolar neurovascular was exposed to the cavity (Fig 4). We then closed the wound in layers and left a silicone tube for drainage, and the wound healed uneventfully. The pathologic report indicated submandibular salivary gland, and the cavity was compatible with Stafne bone cyst. After 6 months of follow-up, the socket healed, and although the shadow of Stafne bone cavity persisted and paresthesia of the left lower lip did not change, the patient’s occlusion was stable and his mouth opening and chewing ability were recovered completely.
Discussion Late mandibular fracture is not a common complication of removal of a lower third molar. According to
FIGURE 2. A, Computed tomography (CT) scan showing a depressed defect (right arrow) at left mandible with complete buccal cortical plate, and a vertical fracture line (downward arrow). B, Axial section of CT scan showing type II class defect of Stafne bone cavity.
FIGURE 4. Reflection in the dental mirror shows the mandibular neurovascular bundle exposed to the bony cavity.
Kao et al. Late Mandibular Fracture After Molar Extraction. J Oral Maxillofac Surg 2010.
Kao et al. Late Mandibular Fracture After Molar Extraction. J Oral Maxillofac Surg 2010.
1700 3 extensive data mining evaluations, the incidence is approximately 0.0046% to 0.0075%.2,4 The condition usually occurs in the patients more than 40 years old with full dentition, and at 2 to 3 weeks postextraction, the left side is affected more frequently than the right, and the incidence is greater in male than in female patients.3 The associated factors of this complication include age, gender, types of impaction, existing infection or bony lesions, surgical technique, and chewing of hard foods after extraction.2-6 Periodontitis and pericoronitis are the most common infectious causes; bony lesions that have been reported are dentigerous cyst and radicular cyst2,4,6; the Stafne bone cyst has not yet been reported as an existing lesion associated with late mandibular fracture after lower third molar extraction. The prevalence of Stafne bony cavity is approximately 0.1% to 0.48% on image examination10-12 of patients with an age range of 40 to 60 years8; the submandibular gland in the cavity is seen according to most reports, whereas no cases have been reported of Stafne bony cavity becoming a risk factor of late mandibular fracture of the lower impacted third molar extraction. The diagnosis of the Stafne bone cavity has usually relied on imaging studies, and panoramic radiography is used for regular examination. The lesion shadow is a radiolucent void with sclerotic border under the mandibular canal, usually at the angle of the mandible but is also found at the anterior or other areas of the mandible. The definitive diagnosis relies on biopsy which is not always necessary. Computed tomography,8,13,14 magnetic resonance imaging, and sialography of the submandibular gland9 can provide sufficient information to make a diagnosis, and the treatment is basically conservative observation.12 The characteristics of our patient are similar to those in other reports of both rare conditions. Our patient was a 54-year-old man with full dentition but with a history of pericoronitis, and the associated lesion was a Stafne bone cavity that was of type II class.8,14 However, a fracture was found at the left side after clicking occurred while chewing, after more than 30 days after lower third molar extraction. The exposed inferior alveolar neurovascular bundle in Stafne bone cavity is rare; the only article mentioning this finding, shown on an image, was reported by Reuter in 1998.13 We confirmed this finding in the surgical procedure. The actual prevalence of persistent paresthesia of the left lower lip was not found in previous reports on late mandibular fracture after extraction, but Reuter’s report also mentioned pares-
LATE MANDIBULAR FRACTURE AFTER MOLAR EXTRACTION
thesia of the lip, mandibular canal passing through the lesion, and inferior alveolar nerve exposed to the bony cavity, which might be a risk factor for numbness. The purpose of this case report is not only to show 2 rare conditions, namely, late mandibular fracture after extraction of the third molar and Stafne bone cyst in 1 patient, but also to remind dentists when preparing a patient for lower third molar extraction that panoramic radiographs should be examined to detect any possible pathologic lesions in this area. Explaining the possible complications of a late fracture and stressing the avoidance of hard food for at least 1 month after lower third molar extraction should be done when obtaining written signed consent.
References 1. Huang IY, Chen CM, Chang SW, et al: Surgical management of accidentally displaced mandibular third molar into the pterygomandibular space—A case report. Kaohsiung J Med Sci 23: 370, 2007 2. Perry PA, Goldgerg MH: Late mandibular fracture after third molar surgery: A survey of Connecticut oral and maxillofacial surgeons. J Oral Maxillofac Surg 58:858, 2000 3. Wagner KW, Otten J-E, Schoen R, et al: Pathological mandibular fractures following third molar removal. Int J Oral Maxillofac Surg 34:722, 2005 4. Woldenberg Y, Gatot I, Bodner L: Iatrogenic mandibular fracture associated with third molar removal. Can it be prevented? Med Oral Patol Cir Buccal 12:E70, 2007 5. Libersa P, Roze D, Cachart T, et al: Immediate and late mandibular fractures after third molar removal. J Oral Maxillofac Surg 60:163, 2002 6. Krimmel M, Reinert S: Mandibular fracture after third molar removal. J Maxillofac Surg 58:1110, 2000 7. Stafne EC: Bone cavities situated near the angle of the mandible. J Am Dent Assoc 29:1969, 1942 8. Shimizu M, Osa N, Okamura K, et al: CT analysis of the Stafne’s bone defects of the mandible. Dentomaxillofac Radiol 35:95, 2006 9. Branstetter BF, Weissman JL, Kaplan SB: Imaging of a Stafne bone cavity: What MR adds and why a new name is needed. AJNR Am J Neuroradiol 20:587, 1999 10. Queroz LMG, Rocha RS, Medeiros KB, et al: Anterior bilateral presentation of Stafne defect: An unusual case report. J Oral Maxillofac Surg 62:613, 2004 11. Courten A, Kuffer R, Samson J, et al: Anterior lingual mandibular salivary gland defect (Stafne defect) presenting as a residual cyst. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 94:460, 2002 12. Correll RW, Jensen JL, Rhyne R: Lingual cortical mandibular defects, a radiographic incidence study. Oral Surg Oral Med Oral Pathol 20:287, 1980 13. Reuter I: An unusual case of Stafne bone cavity with extraosseous course of the mandibular neurovascular bundle. Dentomaxillofac Radiol 27:189, 1998 14. Ariji E, Fujiwara N, Tabata O, et al: Stafne’s bone cavity. Classification based on outline and content determined by computed tomography. Oral Surg Oral Med Oral Pathol 76:375, 1993
LATE MANDIBULAR FRACTURE AFTER MOLAR EXTRACTION
J Oral Maxillofac Surg 68:1698-1700, 2010
Late Mandibular Fracture After Lower Third Molar Extraction in a Patient With Stafne Bone Cavity: A Case Report Yu-Hsun Kao, DDS, MS,* I-Yueh Eric Huang, DDS, MS,† Chao-Ming Chen, DDS,‡ Chun-Wei Wu, DDS, MS,§ Kun-Jung Hsu, DDS,储 and Chun-Min Chen, DDS, MS¶ Surgical removal of the mandibular third molar is a common surgical procedure in dental clinics. Complications may include infection, bleeding, nerve injury, trismus, and accidentally displaced lower third molar,1 but the late fracture of mandible is very rare.2-6 Stafne cyst was first reported by Stafne in 1942 to describe the bone cavity in the angle of the mandible.7 However, Stafne cyst is not a true cyst, and some articles have suggested that the Stafne bony cavity be renamed.8,9 The purpose of this report is to present an unusual case of late mandibular fracture after extraction of a lower third molar in a patient with Stafne bone cavity. To our knowledge, this is the first case report in the English-language literature of these 2 rare conditions in 1 patient.
Report of a Case A 54-year-old Japanese man presented to our clinic with a change of occlusion and swelling at the left mandibular angle area. We reviewed the patient’s history of dental treatment and found that he had had swelling over the left lower third molar area for approximately 1 week and had visited a local dental clinic on October 18, 2007. The dentist took a periapical film, and a left mesio-angulately impacted
Received from Kaohsiung Medical University, Kaohsiung, Taiwan. *Clinical Instructor, Department of Dentistry. †Associate Professor, Department of Oral and Maxillofacial Surgery, and Department of Dentistry. ‡Clinical Instructor, Department of Dentistry. §Clinical Instructor, Department of Dentistry. 储Clinical Instructor, Department of Dentistry. ¶Associate Professor, Department of Dentistry. Address correspondence and reprint requests to Dr Huang: Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung, Taiwan; e-mail: [email protected] © 2010 American Association of Oral and Maxillofacial Surgeons
0278-2391/10/6807-0040$36.00/0 doi:10.1016/j.joms.2009.06.019
third molar with pericoronitis was suspected but cast no radiolucent shadow on the film. The dentist gave him antibiotics and local anesthesia. After acute infection subsided, the dentist extracted the third molar on November 19, 2007. The wound healed uneventfully until the patient experienced a clear clicking sound while eating foods by mid-February 2008, more than 6 weeks after extraction. A few days later, swelling over his left mandibular angle led him to visit his dentist again on February 18, 2008. After taking a Panorex that showed fracture over the left mandibular angle and a radiolucent lesion at the lower border of the mandible, the dentist referred the patient to our department for further evaluation and treatment. However, the patient did not present to our clinic until March 28, 2008, approximately 6 weeks after the fracture. Before this extraction, the patient was a healthy man and had had regular dental examinations; he did not feel any discomfort over the left mandibular angle area. We examined the patient and found tenderness, swelling, and local heat indicating infection over the left mandibular angle; in addition, the patient’s left lower lip was numb and he could not bite to his central occlusion. Panoramic radiography showed a socket of mesio-angulately impacted third molar and a radiolucent shadow with sclerotic cortical margin at the mandibular angle, with the mandibular canal passing through the radiolucent area (Fig 1) We checked the patient’s computed tomography (CT) scan (Fig 2) and, because the report indicated malignancy due to the irregu-
FIGURE 1. Panorex showing the socket of the left lower third molar, a radiolucent lesion with sclerotic margin below the third molar and above the mandibular lower border, with the mandibular canal passing through the lesion. The fracture line is from the socket to the antegonial notch. Kao et al. Late Mandibular Fracture After Molar Extraction. J Oral Maxillofac Surg 2010.
1699
KAO ET AL lar border of the lesion, we suggested a biopsy. After discussion with the patient, we decided to take a biopsy sample from the submandibular area for the radiolucent lesion and to perform open reduction with internal fixation for the mandibular fracture. Because the patient was busy, the operation was arranged for May 2008, about 3 months after the fracture occurred. Because the patient refused a temporary fixation, he was advised to consume a soft diet. Surgery was performed on May 16, 2008, under general anesthesia with an endotracheal tube. A submandibular incision was made and blunt dissection exposed the frac-
FIGURE 3. Photograph showing the healed fracture line (small upward arrow) and the depression of the bony cavity (large upward arrow). Kao et al. Late Mandibular Fracture After Molar Extraction. J Oral Maxillofac Surg 2010.
ture and bony cavity. We found that the fractured bone had healed (Fig 3) and the occlusion was stable, so we did not perform reduction and fixation. The bony cavity was filled with soft tissue, which was removed for pathological examination; after this procedure, we found that the inferior alveolar neurovascular was exposed to the cavity (Fig 4). We then closed the wound in layers and left a silicone tube for drainage, and the wound healed uneventfully. The pathologic report indicated submandibular salivary gland, and the cavity was compatible with Stafne bone cyst. After 6 months of follow-up, the socket healed, and although the shadow of Stafne bone cavity persisted and paresthesia of the left lower lip did not change, the patient’s occlusion was stable and his mouth opening and chewing ability were recovered completely.
Discussion Late mandibular fracture is not a common complication of removal of a lower third molar. According to
FIGURE 2. A, Computed tomography (CT) scan showing a depressed defect (right arrow) at left mandible with complete buccal cortical plate, and a vertical fracture line (downward arrow). B, Axial section of CT scan showing type II class defect of Stafne bone cavity.
FIGURE 4. Reflection in the dental mirror shows the mandibular neurovascular bundle exposed to the bony cavity.
Kao et al. Late Mandibular Fracture After Molar Extraction. J Oral Maxillofac Surg 2010.
Kao et al. Late Mandibular Fracture After Molar Extraction. J Oral Maxillofac Surg 2010.
1700 3 extensive data mining evaluations, the incidence is approximately 0.0046% to 0.0075%.2,4 The condition usually occurs in the patients more than 40 years old with full dentition, and at 2 to 3 weeks postextraction, the left side is affected more frequently than the right, and the incidence is greater in male than in female patients.3 The associated factors of this complication include age, gender, types of impaction, existing infection or bony lesions, surgical technique, and chewing of hard foods after extraction.2-6 Periodontitis and pericoronitis are the most common infectious causes; bony lesions that have been reported are dentigerous cyst and radicular cyst2,4,6; the Stafne bone cyst has not yet been reported as an existing lesion associated with late mandibular fracture after lower third molar extraction. The prevalence of Stafne bony cavity is approximately 0.1% to 0.48% on image examination10-12 of patients with an age range of 40 to 60 years8; the submandibular gland in the cavity is seen according to most reports, whereas no cases have been reported of Stafne bony cavity becoming a risk factor of late mandibular fracture of the lower impacted third molar extraction. The diagnosis of the Stafne bone cavity has usually relied on imaging studies, and panoramic radiography is used for regular examination. The lesion shadow is a radiolucent void with sclerotic border under the mandibular canal, usually at the angle of the mandible but is also found at the anterior or other areas of the mandible. The definitive diagnosis relies on biopsy which is not always necessary. Computed tomography,8,13,14 magnetic resonance imaging, and sialography of the submandibular gland9 can provide sufficient information to make a diagnosis, and the treatment is basically conservative observation.12 The characteristics of our patient are similar to those in other reports of both rare conditions. Our patient was a 54-year-old man with full dentition but with a history of pericoronitis, and the associated lesion was a Stafne bone cavity that was of type II class.8,14 However, a fracture was found at the left side after clicking occurred while chewing, after more than 30 days after lower third molar extraction. The exposed inferior alveolar neurovascular bundle in Stafne bone cavity is rare; the only article mentioning this finding, shown on an image, was reported by Reuter in 1998.13 We confirmed this finding in the surgical procedure. The actual prevalence of persistent paresthesia of the left lower lip was not found in previous reports on late mandibular fracture after extraction, but Reuter’s report also mentioned pares-
LATE MANDIBULAR FRACTURE AFTER MOLAR EXTRACTION
thesia of the lip, mandibular canal passing through the lesion, and inferior alveolar nerve exposed to the bony cavity, which might be a risk factor for numbness. The purpose of this case report is not only to show 2 rare conditions, namely, late mandibular fracture after extraction of the third molar and Stafne bone cyst in 1 patient, but also to remind dentists when preparing a patient for lower third molar extraction that panoramic radiographs should be examined to detect any possible pathologic lesions in this area. Explaining the possible complications of a late fracture and stressing the avoidance of hard food for at least 1 month after lower third molar extraction should be done when obtaining written signed consent.
References 1. Huang IY, Chen CM, Chang SW, et al: Surgical management of accidentally displaced mandibular third molar into the pterygomandibular space—A case report. Kaohsiung J Med Sci 23: 370, 2007 2. Perry PA, Goldgerg MH: Late mandibular fracture after third molar surgery: A survey of Connecticut oral and maxillofacial surgeons. J Oral Maxillofac Surg 58:858, 2000 3. Wagner KW, Otten J-E, Schoen R, et al: Pathological mandibular fractures following third molar removal. Int J Oral Maxillofac Surg 34:722, 2005 4. Woldenberg Y, Gatot I, Bodner L: Iatrogenic mandibular fracture associated with third molar removal. Can it be prevented? Med Oral Patol Cir Buccal 12:E70, 2007 5. Libersa P, Roze D, Cachart T, et al: Immediate and late mandibular fractures after third molar removal. J Oral Maxillofac Surg 60:163, 2002 6. Krimmel M, Reinert S: Mandibular fracture after third molar removal. J Maxillofac Surg 58:1110, 2000 7. Stafne EC: Bone cavities situated near the angle of the mandible. J Am Dent Assoc 29:1969, 1942 8. Shimizu M, Osa N, Okamura K, et al: CT analysis of the Stafne’s bone defects of the mandible. Dentomaxillofac Radiol 35:95, 2006 9. Branstetter BF, Weissman JL, Kaplan SB: Imaging of a Stafne bone cavity: What MR adds and why a new name is needed. AJNR Am J Neuroradiol 20:587, 1999 10. Queroz LMG, Rocha RS, Medeiros KB, et al: Anterior bilateral presentation of Stafne defect: An unusual case report. J Oral Maxillofac Surg 62:613, 2004 11. Courten A, Kuffer R, Samson J, et al: Anterior lingual mandibular salivary gland defect (Stafne defect) presenting as a residual cyst. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 94:460, 2002 12. Correll RW, Jensen JL, Rhyne R: Lingual cortical mandibular defects, a radiographic incidence study. Oral Surg Oral Med Oral Pathol 20:287, 1980 13. Reuter I: An unusual case of Stafne bone cavity with extraosseous course of the mandibular neurovascular bundle. Dentomaxillofac Radiol 27:189, 1998 14. Ariji E, Fujiwara N, Tabata O, et al: Stafne’s bone cavity. Classification based on outline and content determined by computed tomography. Oral Surg Oral Med Oral Pathol 76:375, 1993