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Solitary fracture of the articular eminence: A case report
808
SOLITARY FRACTURE OF TMJ ARTICULAR EMINENCE
J Oral Maxillofac Surg 59:808-810, 2001
Solitary Fracture of the Articular Eminence: A Case Report Andrew Ban Guan Tay, BDS, MDS, FDS RCSEd, FAMS* and Raymond Hong Lian Peck, BDS, FDS RCSEng, FAMS† Fractures of the temporomandibular joint (TMJ) are well documented and almost invariably involve the mandibular condyle. The mechanism of injury is almost always an indirect force transmitted through the mandible from the symphysis, parasymphysis, or body of the mandible to the condyle. The fractures may be intracapsular (involving the condyle) or extracapsular (involving the condylar neck). There have been reports of fractures of the glenoid fossa1-5; the condyle may be displaced into the external auditory meatus1 or the middle cranial fossa.2-5 We report an unusual case of an isolated fracture of the articular eminence without associated condylar fracture.
Report of Case A 31-year-old Chinese national was referred to the Department of Oral and Maxillofacial Surgery in the National Dental Centre from a regional hospital in Singapore for a possible right condylar fracture. The patient was a construction worker who had fallen from a height of 3 stories and had landed on the right side of his body and head 4 days before being referred. There had been no loss of consciousness, and the patient was alert and oriented at the time of presentation. There was a 8-cm long laceration on the right side of the face extending from the temple above the zygomatic
Received from the Department of Oral and Maxillofacial Surgery, National Dental Centre, Singapore, Singapore. *Senior Registrar. †Senior Consultant. Address correspondence and reprint requests to Dr Tay: Department of Oral and Maxillofacial Surgery, National Dental Centre, Singapore, 5, Second Hospital Ave, Singapore 168938; e-mail: [email protected] © 2001 American Association of Oral and Maxillofacial Surgeons
0278-2391/01/5907-0016$35.00/0 doi:10.1053/joms.2001.24301
arch down the right cheek (Fig 1). The laceration had been sutured before the patient was referred to our department. The patient’s occlusion was good, and there was no evidence of midface or mandibular fracture. He had a mouth opening of about 3 cm measured at the central incisors and pain on wide opening. Excursive movements of the mandible were adequate and equal. The facial nerve was intact bilaterally. A panoramic radiograph showed that although there were no maxilla and mandible fractures, there was a horizontal radiolucent line crossing the right articular eminence (Fig 2). This radiolucent line was also seen on open and closed TMJ views (Fig 3). A diagnosis of a fracture of the right articular eminence was made. A computed tomography scan of the TMJ region confirmed the diagnosis (Fig 4). The injury was managed conservatively with mouthopening exercises. On examination 2 weeks later, the patient was well, with good occlusion, and the interincisal mouth opening had improved to 4 cm. The right facial laceration was healing satisfactorily, and there was no trigeminal or facial nerve deficit. There was also no apparent hearing deficit. The patient was to be seen again at 6 months, but returned to his home country before his examination date.
Discussion A Medline search of the English literature revealed only 2 previous case reports of articular eminence fractures. Radecki and Wolf 6 reported a case of a 32-year-old black man who had been assaulted on the left side of his face with a hatchet. He sustained a 10-cm laceration over the parotid and auriculotemporal regions. His mouth opening was slightly restricted, with no deviation on opening. There was some tenderness in the left TMJ. A panoramic radiograph showed a solitary fracture of the left articular eminence. There was no treatment or follow-up data, because the case was presented as a radiographic oddity.
TAY AND PECK
809
FIGURE 1. Clinical view of the laceration of the right face
Keith et al7 reported a case of a 19-year-old man who was the rear-seat passenger in a car involved in a road traffic accident. He sustained severe head injury, a deep vertical laceration in the left preauricular region, and a fracture in the right parasymphyseal region. Preoperative radiographic investigations reFIGURE 3. Tomogram of right TMJ in mouth open positively showing the fractured eminence.
FIGURE 2. Panoramic radiograph showing a fracture line in right articular eminence (arrow).
vealed little other useful information. At surgery, the left facial nerve and parotid duct were found to be intact. A mobile bone fragment was found in the deepest part of the laceration, corresponding to the inferior-most part of the zygomatic process. The bone fragment was attached by periosteum to the skull base anterior to the left condyle. The fractured articular eminence was stabilized with chromic catgut, and the mandible fracture was immobilized with maxillomandibular fixation for 5 weeks. The mandible fracture healed normally, and the occlusion was stable. There was residual weakness of the left facial nerve from an upper motor neuron lesion. There was no restriction of mandibular movement and no deficit in taste or hearing at 6 months after surgery. Of these 3 cases, 2 were diagnosed using panoramic radiography, and one was discovered intraoperatively. Radecki and Wolf6 reported that the lateral skull view failed to show the articular eminence fracture in their patient. It is likely that a panoramic radiograph could not be taken of the unconscious
810
FIGURE 4. Computed tomography scan showing fracture lines in the right articular eminence (arrow).
patient reported by Keith et al7 and plain film views did not show the articular eminence fracture adequately. Although fractures of the articular eminence are rarely reported, the true incidence may be higher because of it being masked by other more major injuries or because of the possibility of missing such injuries on routine plain film investigations. The most suitable investigation for diagnosing such injuries is probably the panoramic radiograph. All 3 cases were caused by direct trauma and a penetrating injury. The zygomatic arch is not weightbearing, and fractures result from a direct force on the arch itself or an indirect force transmitted through the body of the zygomatic bone. It is therefore not surprising that fractures of the articular eminence are uncommon and occur only with direct trauma to the bone. Of the 2 patients in whom the treatment and outcome are known, there was no restriction in mandibular movement, and they did not suffer any apparent injury to the facial nerve, chorda tympani, or auditory apparatus as a result of the articular eminence fracture. Keith et al7 stated that a fracture of the articular eminence could result in damage to the TMJ capsule resulting in scarring and limitation of condylar move-
SOLITARY FRACTURE OF TMJ ARTICULAR EMINENCE
ment and injury to the chorda tympani, which runs medial to the superior joint space, resulting in loss of taste. There may also be the risk of stretching the anterior malleolar ligament, causing to tearing of the tympanic membrane and hearing loss.7 However, a fracture of the articular eminence of the TMJ does not appear to be commonly associated with injury to nearby structures such as the facial nerve, chorda tympani, or auditory apparatus. Keith et al7 noted that surgical procedures on the articular eminence (ie, eminectomy, eminence augmentation) have not resulted in such complications. However, there are no data as to whether such eminence fractures can result in long-term complications such as restriction of condylar movement or resorption of the eminence predisposing to dislocation of the condyle. Articular eminence fractures may be conservatively treated unless there is significant displacement. The inevitable presence of an open wound should allow the eminence fracture to be assessed directly. A significantly displaced articular eminence fracture may possibly cause obstruction to the movement of the condyle and should probably be reduced and fixed with wires, screws, or bone plates, depending on the size of the fractured fragment. Any other associated injuries of the mandible or midface should be treated preferably with bone plate osteosynthesis to allow for early mobilization of the condyles.
References 1. Antoniades K, Karakasis D, Daggilas A: Posterior dislocation of mandibular condyle into external auditory meatus. A case report. Int J Oral Maxillofac Surg 21:212, 1992 2. Ianetti G, Martucci E: Fracture of the glenoid fossa following mandibular trauma. Oral Surg 49:405, 1980 3. Copenhaver RH, Dennis MJ, Kloppedal E, et al: Fracture of the glenoid fossa and dislocation of the mandibular condyle into the middle cranial fossa. J Oral Maxillofacial Surg 43:974, 1985 4. Musgrove BT: Dislocation of the mandibular condyle into the middle cranial fossa. Br J Oral Maxillofac Surg 24:22, 1986 5. Melugin MB, Indresano AT, Clemens SP: Glenoid fossa fracture and condylar penetration into the middle cranial fossa: Report of a case and review of the literature. J Oral Maxillofac Surg 55: 1342, 1997 6. Radecki CA, Wolf SM: Solitary fracture of the articular eminence. Oral Surg Oral Med Oral Pathol 69:768, 1990 7. Keith O, Jones GM, Shepherd JP: Fracture of the articular eminence. Report of a case. Int J Oral Maxillofac Surg 19:79, 1990
SOLITARY FRACTURE OF TMJ ARTICULAR EMINENCE
J Oral Maxillofac Surg 59:808-810, 2001
Solitary Fracture of the Articular Eminence: A Case Report Andrew Ban Guan Tay, BDS, MDS, FDS RCSEd, FAMS* and Raymond Hong Lian Peck, BDS, FDS RCSEng, FAMS† Fractures of the temporomandibular joint (TMJ) are well documented and almost invariably involve the mandibular condyle. The mechanism of injury is almost always an indirect force transmitted through the mandible from the symphysis, parasymphysis, or body of the mandible to the condyle. The fractures may be intracapsular (involving the condyle) or extracapsular (involving the condylar neck). There have been reports of fractures of the glenoid fossa1-5; the condyle may be displaced into the external auditory meatus1 or the middle cranial fossa.2-5 We report an unusual case of an isolated fracture of the articular eminence without associated condylar fracture.
Report of Case A 31-year-old Chinese national was referred to the Department of Oral and Maxillofacial Surgery in the National Dental Centre from a regional hospital in Singapore for a possible right condylar fracture. The patient was a construction worker who had fallen from a height of 3 stories and had landed on the right side of his body and head 4 days before being referred. There had been no loss of consciousness, and the patient was alert and oriented at the time of presentation. There was a 8-cm long laceration on the right side of the face extending from the temple above the zygomatic
Received from the Department of Oral and Maxillofacial Surgery, National Dental Centre, Singapore, Singapore. *Senior Registrar. †Senior Consultant. Address correspondence and reprint requests to Dr Tay: Department of Oral and Maxillofacial Surgery, National Dental Centre, Singapore, 5, Second Hospital Ave, Singapore 168938; e-mail: [email protected] © 2001 American Association of Oral and Maxillofacial Surgeons
0278-2391/01/5907-0016$35.00/0 doi:10.1053/joms.2001.24301
arch down the right cheek (Fig 1). The laceration had been sutured before the patient was referred to our department. The patient’s occlusion was good, and there was no evidence of midface or mandibular fracture. He had a mouth opening of about 3 cm measured at the central incisors and pain on wide opening. Excursive movements of the mandible were adequate and equal. The facial nerve was intact bilaterally. A panoramic radiograph showed that although there were no maxilla and mandible fractures, there was a horizontal radiolucent line crossing the right articular eminence (Fig 2). This radiolucent line was also seen on open and closed TMJ views (Fig 3). A diagnosis of a fracture of the right articular eminence was made. A computed tomography scan of the TMJ region confirmed the diagnosis (Fig 4). The injury was managed conservatively with mouthopening exercises. On examination 2 weeks later, the patient was well, with good occlusion, and the interincisal mouth opening had improved to 4 cm. The right facial laceration was healing satisfactorily, and there was no trigeminal or facial nerve deficit. There was also no apparent hearing deficit. The patient was to be seen again at 6 months, but returned to his home country before his examination date.
Discussion A Medline search of the English literature revealed only 2 previous case reports of articular eminence fractures. Radecki and Wolf 6 reported a case of a 32-year-old black man who had been assaulted on the left side of his face with a hatchet. He sustained a 10-cm laceration over the parotid and auriculotemporal regions. His mouth opening was slightly restricted, with no deviation on opening. There was some tenderness in the left TMJ. A panoramic radiograph showed a solitary fracture of the left articular eminence. There was no treatment or follow-up data, because the case was presented as a radiographic oddity.
TAY AND PECK
809
FIGURE 1. Clinical view of the laceration of the right face
Keith et al7 reported a case of a 19-year-old man who was the rear-seat passenger in a car involved in a road traffic accident. He sustained severe head injury, a deep vertical laceration in the left preauricular region, and a fracture in the right parasymphyseal region. Preoperative radiographic investigations reFIGURE 3. Tomogram of right TMJ in mouth open positively showing the fractured eminence.
FIGURE 2. Panoramic radiograph showing a fracture line in right articular eminence (arrow).
vealed little other useful information. At surgery, the left facial nerve and parotid duct were found to be intact. A mobile bone fragment was found in the deepest part of the laceration, corresponding to the inferior-most part of the zygomatic process. The bone fragment was attached by periosteum to the skull base anterior to the left condyle. The fractured articular eminence was stabilized with chromic catgut, and the mandible fracture was immobilized with maxillomandibular fixation for 5 weeks. The mandible fracture healed normally, and the occlusion was stable. There was residual weakness of the left facial nerve from an upper motor neuron lesion. There was no restriction of mandibular movement and no deficit in taste or hearing at 6 months after surgery. Of these 3 cases, 2 were diagnosed using panoramic radiography, and one was discovered intraoperatively. Radecki and Wolf6 reported that the lateral skull view failed to show the articular eminence fracture in their patient. It is likely that a panoramic radiograph could not be taken of the unconscious
810
FIGURE 4. Computed tomography scan showing fracture lines in the right articular eminence (arrow).
patient reported by Keith et al7 and plain film views did not show the articular eminence fracture adequately. Although fractures of the articular eminence are rarely reported, the true incidence may be higher because of it being masked by other more major injuries or because of the possibility of missing such injuries on routine plain film investigations. The most suitable investigation for diagnosing such injuries is probably the panoramic radiograph. All 3 cases were caused by direct trauma and a penetrating injury. The zygomatic arch is not weightbearing, and fractures result from a direct force on the arch itself or an indirect force transmitted through the body of the zygomatic bone. It is therefore not surprising that fractures of the articular eminence are uncommon and occur only with direct trauma to the bone. Of the 2 patients in whom the treatment and outcome are known, there was no restriction in mandibular movement, and they did not suffer any apparent injury to the facial nerve, chorda tympani, or auditory apparatus as a result of the articular eminence fracture. Keith et al7 stated that a fracture of the articular eminence could result in damage to the TMJ capsule resulting in scarring and limitation of condylar move-
SOLITARY FRACTURE OF TMJ ARTICULAR EMINENCE
ment and injury to the chorda tympani, which runs medial to the superior joint space, resulting in loss of taste. There may also be the risk of stretching the anterior malleolar ligament, causing to tearing of the tympanic membrane and hearing loss.7 However, a fracture of the articular eminence of the TMJ does not appear to be commonly associated with injury to nearby structures such as the facial nerve, chorda tympani, or auditory apparatus. Keith et al7 noted that surgical procedures on the articular eminence (ie, eminectomy, eminence augmentation) have not resulted in such complications. However, there are no data as to whether such eminence fractures can result in long-term complications such as restriction of condylar movement or resorption of the eminence predisposing to dislocation of the condyle. Articular eminence fractures may be conservatively treated unless there is significant displacement. The inevitable presence of an open wound should allow the eminence fracture to be assessed directly. A significantly displaced articular eminence fracture may possibly cause obstruction to the movement of the condyle and should probably be reduced and fixed with wires, screws, or bone plates, depending on the size of the fractured fragment. Any other associated injuries of the mandible or midface should be treated preferably with bone plate osteosynthesis to allow for early mobilization of the condyles.
References 1. Antoniades K, Karakasis D, Daggilas A: Posterior dislocation of mandibular condyle into external auditory meatus. A case report. Int J Oral Maxillofac Surg 21:212, 1992 2. Ianetti G, Martucci E: Fracture of the glenoid fossa following mandibular trauma. Oral Surg 49:405, 1980 3. Copenhaver RH, Dennis MJ, Kloppedal E, et al: Fracture of the glenoid fossa and dislocation of the mandibular condyle into the middle cranial fossa. J Oral Maxillofacial Surg 43:974, 1985 4. Musgrove BT: Dislocation of the mandibular condyle into the middle cranial fossa. Br J Oral Maxillofac Surg 24:22, 1986 5. Melugin MB, Indresano AT, Clemens SP: Glenoid fossa fracture and condylar penetration into the middle cranial fossa: Report of a case and review of the literature. J Oral Maxillofac Surg 55: 1342, 1997 6. Radecki CA, Wolf SM: Solitary fracture of the articular eminence. Oral Surg Oral Med Oral Pathol 69:768, 1990 7. Keith O, Jones GM, Shepherd JP: Fracture of the articular eminence. Report of a case. Int J Oral Maxillofac Surg 19:79, 1990