Superior dislocation of mandibular condyle into the middle cranial fossa

Copyright9

In1. J. OralMaxillofac. Surg. 1997;26:2~30 printed in Denmark. All rights reserved

1997

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Oral & Maxillofacial Surgery ISSN 0901-5027

Superior dislocation of mandibular condyle into the middle cranial fossa

Xing Long, Chanzen Hu, Jihong Zhao, Jinrong Li, Guozhi Zhang Department of Oral and Maxillofacial Surgery, Hubei Medical University, Wuhan, F~R. CNna

A case report X. Long, C. Hu, J. Zhao, J. Li, G. Zhang: Superior dislocation o f mandibular condyle into the middle cranial fossa. Int. J. Oral Maxillofac. Surg. 1997; 26: 29-30. 9 Munksgaard, 1997 Abstract. A case of superior dislocation of the mandibular condyle into the middle cranial fossa is presented. A modified method o f reducing the mandibular condyle was used, and restitution of the perforated glenoid fossa was achieved by a combination of titanium plate and repair of the articular disk.

Few cases of superior dislocation of the mandibular condyle into the middle cranial fossa have been reported in the literature 1-s. Early diagnosis and treatment are important to minimize cerebral complications such as leakage of cerebrospinal fluid and hemorrhage 3. This paper reports one such case and presents a modified method of treatment for superior dislocation of the condyle.

open bite and inability to place the teeth in normal occlusion. There were no soft-tissue wounds or sensory disturbances. The left mandibular condyle could not be palpated,

Key words: mandibular condyle; trauma;

cranial fossa; temporomandibularjoint. Accepted for publication 15 July 1996

and the right condyle was palpable anterior to the glenoid fossa. Radiographic examination demonstrated no obvious facial fracture. Tomography of

Case report A 38-year-old woman was injured in a motorcycle accident, the right side of her head striking the road. There was no loss of consciousness. The patient complained of severe headache, reduced visual acuity in the left eye, and difficulty in jaw movement. Emergency treatment for fracture of the right temporoparietal bone was provided. Bleeding from the right external auditory canal was noted; however, perforation into the cranial fossa was not recognized. Fifteen days after the injury, the patient attended a specialist clinic of the Department of Oral and Maxillofacial Surgery, Hubei School of Stomatology (China). On examination, deviation of the mandible to the left side was noted and maximal mouth opening reached only 8 ram. There was an anterior

Fig. 1. a) Preoperative sagittal tomogram showed penetration of condyle into middle cranial fossa and loose bone fragment in anterosuperior location, b) CT scan in coronal plane confirmed upward displacement of condylar head through condylar fossa into cranial cavity.

30

Long et al. dible was centered, and good condylar movement was regained.

Discussion

Fig. 2. Diagram of titanium plate placed over perforated glenoid fossa and secured by screws on zygomatic arch.

the left temporomandibular joint in the sagittal plane demonstrated that the left mandibular condyle had penetrated the middle cranial fossa together with a bone fragment from the roof of the glenoid fossa (Fig. la). Coronal computed tomography (CT) scan confirmed upward displacement of the condyle (Fig. lb). Open reduction of the displaced left mandibular condyle was undertaken under general anesthesia. The temporomandibuIar joint was approached via a preauricular incision. A piece of rubber, 15 mm in height, was placed between the teeth in the left molar region, and. by upward pressure applied to the chin, the condyle was retracted from the middle cranial fossa. The reduction was controlled by grasping the condylar neck with a Kocher's forceps, and simultaneous downward pull was exerted by opening a mouth gag placed between the articular eminence and the sigrnoid notch. The perforation into the middle cranial fossa was confirmed by viewing with an arthroscope. The dura mater was intact and the roof of the glenoid fossa was displaced anterosuperiorly. The posterior band of the articular disk and retrodiskal tissues were pushed into the middle cranial fossa. The articular cartilage of the condylar head was damaged. An attempt to withdraw the bone fragment under arthroscopic control was unsuccessful because the fragment adhered to the dura. The condylar head was smoothed with a bone file. A T-shaped titanium miniplate was adapted across the glenoid fossa and secured at the lateral edge of the glenoid fossa with screws (Fig. 2). The disk was repaired with sutures and layered between the titanium plate and the repositioned condylar head. After the operation, the left mandibular condyle remained in the reduced position at the glenoid fossa. The teeth were restored to normal occlusion. The midline of the man-

The mechanism of mandibular condyle dislocation into the middle cranial fossa remains unclear. M o s t authorities consider that direct trauma to the anterior mandible with the m o u t h wide open is the most likely cause of this injury 5. The patient is predisposed to this type of dislocation particularly when the condyle head is small and rounded 8. Although the mechanism of injury in this case remains speculative, it is likely that the impact force on the right temporoparietal bone was transmitted along the right mandible through the left mandibular ramus to the condyle. The patient most probably had her m o u t h open at the m o m e n t of injury, and the left condyle then penetrated into the middle cranial fossa. The clinical characteristics of superior dislocation of the mandibular condyle into the middle cranial fossa include asymmetric shortening of the mandibular ramus, deviation of the mandible, malocclusion, anterior open bite, and neurologic injuries. These findings may also be found in condylar fracture. Therefore plain tomography and/or C T are useful to establish the correct diagnosis. The aim of treatment is to reposition the dislocated condyle, restore the normal occlusion and mandibular function, and minimize permanent cerebral complications. Various procedures in this operation have been proposed 14'6'7, and most surgeons have reported the repair of the cranial perforation with a rib or cranial bone graft. The use of a titanium plate as a prosthetic device to f o r m the roof of the broken glenoid fossa has been reported only in one case. Although the condyle can be repositioned in the normal relationship inside the fossa and the occlusion restored, the long term effect of the plate in direct apposition with the articular disk and the condylar head remains uncertain. An extended role for the temporomandibular joint arthroscope was highlighted in this case. A l t h o u g h the bone

fragment could not be retrieved from the cranial fossa, this tool was nevertheless useful in confirming the location of any loose or foreign bodies through a small access opening.

Acknowledgments. We thank Dr L1M CHEUNG and Dr NABIL SAMMANof the University of Hong Kong for assistance in revising the manuscript.

References 1. BALDWINAJ. Superior dislocation of the intact mandibular condyle into the middle cranial fossa. J Oral Maxillofac Surg 1990: 48: 623-8. 2. CHRIST1ANSENRL. Condylar penetration into the middle cranial fossa. J Craniomandib Disord Facial Oral Pain 1989: 3: 1004. 3. CHUONGR. Management of mandibular condyle penetration into the middle cranial fossa: case report. J Oral Maxillofac Surg 1994: 52: 8804. 4. ENG~VALLS, FISCHERK. Dislocation of the mandibular condyle into the middle cranial fossa: review of the literature and report of a case. J Oral Maxillofac Surg 1992: 50: 524~7. 5. IHALAXNENU, TASAMENA. Central luxation or dislocation of the mandibular condyle into the middle cranial fossa. A case report and review of the literature. Int J Oral Maxillofac Surg 1983: 12:39 45. 6. MUSGROVEBT. Dislocation of the mandibular condyle in the middle cranial fossa. Br J Oral Maxillofac Surg 1986: 24: 22-7. 7. PAULETTESW, TROP R, ~r MD, NAZIF MM. Intrusion of the mandibular condyle into the middle cranial fossa. Report of a case in an 11-year-old girl. Pediatr Dent 1989: 11: 68-71. 8. WHITACREWB. Dislocation of the mandibular condyle into the middle cranial fossa. Review of the literature and report of a case. Plast Reconstr Surg 1966: 38: 23-6.

Address: Professor Guo-Zhi Zhang Department of Oral and Maxillofacial Surgery School of Stomatology Hubei Medical University Wuhan, Hubei 430070 P.R. China