Cliff A. Megerian

Temporal Bone Fractures: Otic Capsule Sparing versus Otic Capsule Violating Clinical and Radiographic Considerations

OBJECTIVE To assess the practicality and utility of the traditional classification system for temporal bone fracture (transverse vs. longitudinal) in the modern Level I trauma setting and to determine whether a newer system of designation (otic capsule sparing vs. otic capsule violating fracture) is practical from a clinical and radiographic standpoint. METHODS The University of Massachusetts Medical Center Trauma Registry was reviewed for the years 1995 to 1997. Patients identified as sustaining closed head injury were reviewed for basilar skull fracture and temporal bone fracture. Clinical and radiographic records were evaluated by using the two classification schemes. RESULTS A total of 2,977 patients were treated at the trauma center during this time. Ninety (3%) patients sustained a temporal bone fracture. The classic characterization of transverse versus longitudinal fracture (20% vs. 80%, respectively) was unable to be determined in this group; therefore, clinical correlation to complications using that paradigm was not possible. By using the otic capsule violating versus sparing designation, an important difference in clinical sequelae and intracranial complications became apparent. Compared with otic capsule sparing fractures, patients with otic capsule violating fractures were approximately two times more likely to develop facial paralysis, four times more likely to develop CSF leak, and seven times more likely to experience profound hearing loss, as well as more likely to sustain intracranial complications including epidural hematoma and subarachnoid hemorrhage. CONCLUSION The use of a classification system for temporal bone fractures that emphasizes violation or lack of violation of the otic capsule seems to offer the advantage of radiographic utility and stratification of clinical severity, including severity of Glasgow Coma Scale scores and intracranial complications such as subarachnoid hemorrhage and epidural hematoma.

Hearing preservation surgery for small endolymphatic sac tumors in patients with von Hippel-Lindau syndrome.

Objective To determine the incidence of bilateral endolymphatic sac tumors in von Hippel-Lindau syndrome and to describe the technique and results of hearing preservation surgery for small endolymphatic sac tumors in a series of patients with von Hippel-Lindau syndrome. Study Design Analysis of the literature to determine the incidence of bilateral endolymphatic sac tumors and a retrospective case review of hearing preservation surgery for removal of small endolymphatic sac tumors in four patients with von Hippel-Lindau syndrome. Setting Tertiary care academic medical centers. Patients Four patients with von Hippel-Lindau syndrome (three with bilateral endolymphatic sac tumors) and progressive sensorineural hearing loss in which preoperative imaging studies revealed in situ or small endolymphatic sac tumors without ipsilateral labyrinthine destruction. Intervention All four patients had complete surgical excisions of the endolymphatic sac tumor via one of three surgical approaches with the goal of hearing preservation. One patient had bilateral surgery. Main Outcome Measures Audiometric and radiographic. Results Nearly one-third (30.2%) of patients with von Hippel-Lindau syndrome and endolymphatic sac tumors have bilateral disease. All four patients (five ears) maintained serviceable hearing postoperatively after surgical excision of the endolymphatic sac tumor via a variety of approach options. Conclusion The discovery of a small or in situ endolymphatic sac tumor affords the patient the option of surgical removal with hearing preservation. This is critical in the patient with von Hippel-Lindau syndrome who is at risk for bilateral disease and complete bilateral anacusis if tumor growth progresses.

Merkel cell carcinoma of the external auditory canal invading the intracranial compartment

PURPOSE To report an unusual case of an intracranial extension of Merkel cell carcinoma originating in the external ear canal and causing neurological deficits. CASE REPORT An 86-year-old woman, with a 16-month history of an external auditory canal mass, presented with hemiparesis, facial paralysis, and obtundation. Radiographic images showed an intracranial mass extending into the petrous bone. METHOD The patient had a craniotomy for intracranial tumor resection with concurrent mastoidectomy for facial nerve decompression and obtundation and hemiparesis were resolved. Residual tumor was subsequently treated with adjuvant radiation therapy, and facial nerve function consequently improved. CONCLUSION Merkel cell tumors rarely invade the intracranial compartments. Residual tumor and neurological deficits may respond to adjuvant radiation therapy.

Improved axon diameter and myelin sheath thickness in facial nerve cable grafts wrapped in temporoparietal fascial flaps

Injury to the facial nerve in the temporal bone presents a challenge to the recovery of nerve function, in that the fallopian canal in which it lies is poorly vascularized. This study was designed to determine if wrapping an intratemporal facial nerve defect repaired with a cable graft with a well-vascularized temporoparietal fascial (TPF) flap would improve facial nerve regeneration. To evaluate this question, a defect was created in the intratemporal left facial nerve of 10 rabbits. All nerves were repaired using cable grafts. In 5 animals, the nerve graft was wrapped with temporoparietal fascia, whereas in the other 5 rabbits it was not. Three additional animals underwent exposure only. The contralateral nerve served as a control in all animals. Quantitative analysis of the nerve graft 12 weeks after repair revealed greater recovery of original fiber diameter and myelin sheath thickness in TPF flap-wrapped repairs. Histological evidence of improved neural regeneration and functional nerve recovery was also seen in the repairs where the TPF flap was utilized. Nerve conduction and electromyographic studies of the cable-grafted nerve at 6 and 12 weeks were equivocal, however.

Minimally Invasive Technique of Auricular Cartilage Harvest for Tissue Engineering

Tissue engineered human cartilage is presently being utilized in clinical research programs in a variety of medical disciplines including otolaryngology, urology, and orthopedics. In this study, we present a new methodology for auricular cartilage harvest that can be applied to tissue engineering. Eight 16-week-old pigs were subjected to a traditional open cartilage harvest technique involving suture closure, while the other ear was subjected to the closed stitchless cartilage harvest, using a 12-gauge core biopsy needle. Surgical time was significantly (p < 0.0001) shorter (3.5 +/- 2.8 min for closed vs. 14.4 +/- 5 min for open), and no sutures where utilized in the closed technique. Sample weights were significantly (p < 0.00001) greater (0.115 +/- 0.028 g vs. 0.045 +/- 0.005 g) for the closed techniques. However, the minimally invasive closed technique had fewer incidents of bruising, hematoma, long-term stitch abscess, and scarring. Cell culture data shows no disadvantage to either technique with regards to cell growth characteristics. Final histological data from donor ears indicates favorable results with the minimally invasive technique. This technique preserves cell viability and isolation efficiency while decreasing surgical time and lessening postoperative complications.

Selective retrosigmoid vestibular neurectomy without internal auditory canal drill-out: An anatomic study

Objective It is well established that selective vestibular nerve section by means of the retrosigmoid or posterior fossa approach can be accomplished with or without drill-out of the internal auditory canal (IAC) by virtue of the presence or absence of a surgically accessible cleavage plane between the vestibular and cochlear nerves. Some reports have indicated that a majority of patients would be amenable to successful separation of the vestibular nerve from the cochlear nerve medial to the IAC, thus obviating the need for IAC drill-out and associated complications. However, other reports have indicated routine difficulty in finding a satisfactory vestibulocochlear cleavage plane within the cerebellopontine angle. This in situ cadaver study was undertaken to determine whether normal anatomic relationships support the hypothesis that selective vestibular nerve section can be accomplished by means of the posterior fossa approach without the need for concomitant IAC drill-out in a majority of circumstances. Methods A retrosigmoid approach to the posterior fossa was performed bilaterally on 36 intact human cadavers. After displacement of the cerebellum, an operating surgical microscope was used to visualize the cerebellopontine angle in the surgical position. The ability to develop a satisfactory cleavage plane between the vestibular and cochlear nerves without the need for drill-out of the IAC was established in each case. Results Seventy-two vestibulocochlear nerve bundles in 36 intact human cadavers were analyzed. A vestibulocochlear nerve cleavage plane within the cerebellopontine angle amenable to neurectomy medial to the porus of the IAC was observed in 81% left and 69% right vestibulocochlear nerve bundles (average, 75%). The facial nerve was found deep or anterior to the vestibulocochlear nerve bilaterally in all cases examined. The anterior inferior cerebellar artery, or a branch of the artery, was found to cross the plane between the facial and vestibulocochlear nerve bundles within the lateral cerebellopontine angle in 47% of the cases on the left and in 50% of cases on the right. Conclusions A vestibulocochlear nerve cleavage plane amenable for selective vestibular nerve transection without drilling the IAC was found in 75% of the 72 cerebellopontine angles studied. The facial nerve consistently lies deep or anterior to the vestibulocochlear nerve within the cerebellopontine angle with the retrosigmoid approach. These findings support the rational and feasibility of avoiding drill-out of the IAC in the majority of circumstances when performing selective vestibular neurectomy by means of the posterior fossa approach for Ménières syndrome and other vestibular disorders.

Facial canal decompression leads to recovery of combined facial nerve paresis and trigeminal sensory neuropathy : Case report

BACKGROUND Trigeminal sensory neuropathy is often associated with facial idiopathic nerve paralysis (Bells palsy). Although a cranial nerve viral polyneuropathy has been proposed as the usual cause, in many instances the etiology remains unclear. This case report of recovery of both trigeminal and facial neuropathy after surgical decompression of the facial nerve suggests an anatomic link. METHODS A case of a 39-year-old woman presenting with recurrent unilateral facial paralysis is summarized. Her fifth episode, which did not spontaneously recover, was associated with retroorbital and maxillary pain as well as sensory loss in the trigeminal distribution. RESULTS A middle cranial fossa approach for decompression of the lateral internal auditory canal, labyrinthine segment of the facial nerve and the geniculate ganglion was performed. The patients pain and numbness resolved immediately postoperatively, and the facial paralysis improved markedly. CONCLUSION This result implicates a trigeminal-facial reflex as hypothesized by others. It suggests that decompression of the facial nerve can lead to improvement in motor and sensory function as well as relief of pain in some patients with combined trigeminal and facial nerve dysfunction.