Kyle P. Allen

Superior Semicircular Canal Dehiscence in Patients with Spontaneous Cerebrospinal Fluid Otorrhea

Objective To determine the prevalence of superior semicircular canal dehiscence (SCD) in patients with spontaneous cerebrospinal fluid (CSF) otorrhea. Study Design Case series with chart review. Setting Tertiary care referral center. Subjects and Methods Patients included have undergone a middle fossa craniotomy for repair of spontaneous CSF otorrhea between January 2007 and December 2011. The main outcome measure is the presence or absence of SCD observed during spontaneous CSF leak repair. Computed tomography (CT) imaging was also reviewed to determine the diagnostic accuracy of this modality. Results Thirty-three ears in 31 patients underwent surgical repair for spontaneous CSF otorrhea via a middle fossa craniotomy. The average age at the time of repair was 60.5 years, and 80.6% of patients were female. A dehiscence of the superior canal was observed in 15.2% of ears (16.1% of individuals). No significant difference in age, body mass index, or sex was noted between those patients with or without a superior canal dehiscence. For the diagnosis of SCD, coronal CT was 100% sensitive and 91.7% specific. The positive predictive value and negative predictive value of CT were 66.7% and 100%, respectively. Conclusion The prevalence of superior semicircular canal dehiscence in ears with spontaneous otorrhea is 15.2%. This prevalence is greater than the 0.5% reported in a temporal bone study of ears not selected for CSF otorrhea.

Lumbar subarachnoid drainage in cerebrospinal fluid leaks after lateral skull base surgery.

Objective To determine the efficacy of lumbar drainage in managing cerebrospinal fluid (CSF) leak after lateral skull base surgery. Study Design Retrospective case review. Setting Academic tertiary referral center. Patients Patients who had a lumbar subarachnoid drain placed after a lateral skull base procedure between July 1999 and February 2010 were included. Interventions Patients were identified by searching medical records for lateral skull base approach Current Procedural Terminology codes. The following variables were recorded for each subject: diagnosis, type of lateral skull base operation, duration of lumbar drainage, need for revision surgery, and presence of meningitis. Main Outcome Measure Successful cessation of postoperative CSF leakage. Results Five hundred eight charts were reviewed, and 63 patients were identified who received a lumbar drain after a lateral skull base operation. The most common diagnosis was acoustic neuroma in 61.9%. The most common skull base approaches were the translabyrinthine, middle fossa, and transpetrosal approaches. Approximately 60.3% of patients had CSF rhinorrhea, 23.8% had an incisional leak, and 14.3% had otorrhea. The mean duration of lumbar drainage was 4.6 days. Forty eight (76.2%) study subjects had resolution of their CSF leak with lumbar drainage. Fifteen patients (23.8%) required revision surgery to stop the CSF leak. Lumbar drainage was successful in 90% of leaks after the translabyrinthine approach but in only 50% of those undergoing a suboccipital approach, which was a statistically significant difference. Conclusion Postoperative CSF leaks after lateral skull base surgery can be managed with a lumbar subarachnoid drain in a majority of cases but is more successful after the translabyrinthine than the suboccipital approach. Recurrent CSF leaks after lumbar drainage is likely to require a revision operation.

Elevated intracranial pressure in patients with spontaneous cerebrospinal fluid otorrhea

To determine the prevalence of elevated intracranial hypertension in patients with spontaneous cerebrospinal fluid otorrhea (SCSFO).

The Association of Meningitis with Postoperative Cerebrospinal Fluid Fistula

Objective To determine the risk factors for and the clinical course of postoperative meningitis following lateral skull base surgery and to determine its relationship to cerebrospinal fluid (CSF) fistula. Patients Patients undergoing lateral skull base surgery between July 1999 and February 2010 at an academic tertiary referral center. All subjects had culture-proven meningitis or suspected bacterial meningitis in the postoperative period. Medical records were compared with the lateral skull base patients who did not develop meningitis. Results Of 508 procedures, 16 patients developed meningitis (3.1%). The most common diagnosis was acoustic neuroma in 81.3%; 68.8% of patients had a CSF leak prior to onset of meningitis, and 50% received a lumbar drain. The median time from surgery to the onset of meningitis was 12 days with a range of 2 to 880 days. The relative risk of developing meningitis in the setting of postoperative CSF fistula is 10.2 (p < 0.0001). No meningitis-associated mortality was observed. Conclusions Postoperative meningitis occurred in a small number of patients undergoing lateral skull base surgery. A postoperative CSF fistula leads to an increased risk of meningitis by a factor of 10.2.

Clinical Impact of Early CT Scans after Lateral Skull-Base Surgery

Objective To determine the frequency and clinical significance of abnormalities on postoperative computerized tomography (CT) scans performed within 24 hours after lateral skull base surgery. Study Design Case series with chart review. Setting Inpatient tertiary care hospital. Methods Adult patients undergoing lateral skull base surgery were identified using CPT code search from January 2010 to January 2013. Patient demographics, type of skull base lesion, surgical approach, length of operation, time between end of the surgery and CT scan, CT scan findings, and patients’ postsurgical neurologic status were collected. Results One hundred and seventy-two patients were identified who had a postoperative CT scan after lateral skull base surgery. Diagnoses included schwannoma (95), cerebrospinal fluid fistula (29), middle fossa encephaloceles (9), meningioma (13), superior semicircular canal dehiscence (12), and other disease processes (14). The approaches were middle fossa (64), translabyrinthine (70), suboccipital (17), infratemporal (8), and combined/other (13). Mild pneumocephalus was almost always found, along with mild extra-axial blood. Twenty-four patients had significant mass effect found on CT scan, but this was present preoperatively. Three patients had a mild subdural without neurological decline. No patient suffered any clinically significant neurological decline, although 5 patients reported finger numbness that resolved spontaneously and 2 patients had confusion in the immediate postoperative period. Conclusion Clinically significant abnormalities on immediate postoperative CT scans were rare, as were cases of neurological decline. Further prospective studies could determine a more cost-effective algorithm for routine use of postoperative imaging.

Cochlear implantation requiring a retrofacial approach to the round window

Objective To describe three cases of cochlear implantation utilizing a retrofacial approach to the round window. Study Design Retrospective case review. Patients Three patients with sensorineural hearing loss undergoing cochlear implantation. Interventions Cochlear implantation via a retrofacial approach to the round window. Results Three patients were noted to have inadequate visualization of the round window using a standard posterior tympanotomy at the time of their cochlear implant surgery. A retrofacial approach was performed to provide exposure of the round window to ensure correct placement of the electrode array. Intraoperative photos and postoperative imaging are demonstrated. Conclusion When a laterally or anteriorly positioned facial nerve obscures visualization of the round window, a retrofacial approach is a possible route to visualize the round window.

Recurrent meningitis secondary to a petrous apex meningocele.

This case report describes a patient who was found to have a cerebrospinal fluid (CSF) leak originating from the petrous apex. The patient initially presented with multiple bouts of meningitis. The patient was treated surgically via a middle cranial fossa approach but presented five years later with recurrent meningitis and was found to have an osseous defect of the petrous apex which was not recognized prior to the initial surgery.

Intratemporal traumatic neuromas of the facial nerve: evidence for multiple etiologies.

Objective To describe 2 patients with traumatic neuromas of the intratemporal facial nerve in the absence of trauma. Study Design Retrospective case review. Setting Tertiary care referral center. Patients Patients included underwent resection of an intratemporal facial nerve mass. Upon pathologic evaluation, the patients were found to have traumatic neuromas of the facial nerve. Intervention(s) Patients underwent resection of an intratemporal facial traumatic neuroma. Histopathologic evaluation was performed including an immunohistochemistry evaluation. Results Two patients were identified with intratemporal facial nerve traumatic neuromas. The patients had no significant history of trauma or chronic inflammatory process. Pathologic evaluations, including immunohistochemistry, of the excised masses were consistent with traumatic neuromas. All tumors were noted to have a disorganized collection of axons and were not consistent with the expected diagnosis of schwannoma. Tumors involved the tympanic and vertical segments of the facial nerve. A cavernous angioma was found within one mass and is thought to be the etiology of neuroma formation. Conclusion Traumatic neuromas are possible in the intratemporal facial nerve in the absence of trauma. A cavernous angioma of the facial nerve is a newly described possible cause of traumatic neuroma formation.

Bilateral Fallopian Canal Arachnoid Cysts in a Patient With Spontaneous Cerebrospinal Fluid Otorrhea

A 39-year-old obese (body mass index, 48.8) woman presented after a 3-month history of unremitting, watery drainage from her right ear. A tympanostomy tube had been placed for a unilateral middle ear effusion present 9 months before tube placement. Her otorrhea had been recalcitrant to treatment with oral or topical antibiotics. She had no facial nerve dysfunction. Fluid was collected by her initial otolaryngologist and found to contain beta-2 transferrin, consistent with CSF. Computed tomography (CT) was obtained of the head, and the labyrinthine fallopian canals were noted to be expanded bilaterally with an associated expansion of the geniculate fossae. Upon assuming her care, a noncontrast high-resolution CT and a noncontrast magnetic resonance imaging (MRI) of the temporal bones were performed. Just before obtaining the new imaging studies, the tube became occluded, and her drainage abated. Her repeat CT again demonstrated the abnormalities of the fallopian canal as well as irregularity and thinning of the tegmenmastoideum and tympani on the right. The middle ear and mastoid on the right were completely opacified. The T2-weightedMRI demonstrated hyperintensity of the right middle ear and mastoid air cells consistent with fluid. The bilateral regions of the geniculate facial nerves were noted to have a cystic appearance: hypointense on T1-weighted images and hyperintense on

En Bloc Resection of the Temporal Bone and Temporomandibular Joint for Advanced Temporal Bone Carcinoma

Advanced skin malignancies involving the temporal bone can involve the temporomandibular joint and glenoid fossa. Many of these tumors can be removed with a lateral temporal bone resection; however, extensive involvement of the glenoid fossa should include an en bloc resection of the temporal bone, glenoid fossa, and condyle. We describe a novel surgical approach that is an extension of a temporal bone resection that includes the glenoid fossa and condyle in an en bloc resection with the temporal bone. This procedure has been performed in 7 patients with advanced carcinoma of the temporal bone involving the glenoid fossa. There were no short-term complications as a result of the surgical approach. The addition of a middle fossa craniotomy and inclusion of the glenoid fossa and condyle as part of an en bloc resection of the temporal bone can be performed safely.