Todd A. Hillman

Reversible peripheral vestibulopathy: The treatment of superior canal dehiscence.

OBJECTIVE: Superior canal dehiscence (SCD) is a recently described disorder that results from absence of bone over the superior semicircular canal. We have reviewed 30 cases of SCD found at our institution and report their presentation, workup, and response to therapy. STUDY DESIGN: Retrospective chart review of all patients diagnosed with SCD from 1999 to 2004 at the University of Utah. RESULTS: Thirty patients were identified with SCD. Patients presented with chronic disequilibrium (63%), Tullios phenomenon (41%), pressure evoked vertigo (44%), hearing loss (30%), and pulsatile tinnitus (7%). ENG performed early in our series revealed abnormal nystagmus with sound presentation, Valsalva, or tympanogram; however, history and CT examination alone was used to identify this condition in most of our patients. Twenty-seven of the 30 patients had some symptoms related to SCD; the other 3 were found to have incidental SCD on CT examination. Of these patients, 14 had severe enough symptoms to warrant operative intervention. All, but one had resolution of their symptoms after completion of intervention. CONCLUSIONS: Superior canal dehiscence is a highly treatable form of vestibulopathy once recognized. When patients present with typical symptoms, workup with CT is reliable and accurate. Surgical intervention results in reversal of symptoms in most cases with low morbidity. EBM rating: C-4

Cochlear nerve stimulation with a 3-dimensional penetrating electrode array.

Hypothesis An array of penetrating microelectrodes can be implanted into the cochlear nerve to produce stable evoked responses with important electrophysiologic advantages over conventional electrode technology. Background A totally implantable cochlear implant system would benefit from new electrode technology that lowers the current required for stimulation. Modern cochlear implant arrays placed in the scala tympani have an appreciable distance between the electrodes and the cochlear nerve, the site of intended stimulation. This distance can create the problem of cross-talk, limiting the number of electrodes that can represent discrete frequencies over a given length as well as significantly increasing stimulation thresholds and producing nonfocal stimulation of the fibers in the nerve. An electrode in direct contact with neurons in the cochlear nerve could reduce these problems. The Utah Electrode Array is a novel, three-dimensional, penetrating electrode array intended for direct neural stimulation with the potential ability to implant up to 200 electrodes directly into the cochlear nerve. Methods Arrays containing 6 to 19 electrodes were implanted acutely into six separate cat cochlear nerves for analysis. Thresholds and input/output functions were measured with electrically induced auditory brainstem responses. Results Current injections in 38 of 70 implanted electrodes produced stable brainstem responses after implantation. The median threshold was 15 &mgr;A. Conclusions An array of penetrating electrodes can be implanted into the cochlear nerve and used to evoke brainstem responses. The responses are of low threshold and are stable. Arrays of electrodes, inserted into auditory nerve, could form the neural interfaces for the next generation of auditory prostheses.

Jugular Foramen Schwannomas: Diagnosis, Management, and Outcomes

Objectives/Hypothesis: To describe the presentation, radiographic findings, and surgical management of seven patients who have been diagnosed and treated with jugular foramen schwannomas at the University of Utah.

Vestibular Nerve Section Versus Intratympanic Gentamicin for Meniere's Disease

Objectives/Hypothesis: Vestibular nerve section and transtympanic gentamicin administration are procedures with proven efficacy in the treatment of vertigo associated with Menieres disease refractory to medical management. Hearing loss is a known complication of each of these procedures; however, there has not been a report of hearing results of both treatments from a single institution.

Association of benign intracranial hypertension and spontaneous encephalocele with cerebrospinal fluid leak.

Objective To determine the incidence of intracranial hypertension in patients with spontaneous encephalocele with cerebrospinal fluid (CSF) leak. Study Design Retrospective case review. Setting Tertiary care neurotology practice. Patients Patients presenting between 2008 and 2011 with spontaneous encephalocele and CSF leak in the temporal bone. Intervention(s) Lumbar puncture with opening pressure measurement after encephalocele repair. Main Outcome Measures Patient age, sex, postoperative course, body mass index, and postoperative intracranial pressure. Results Of the 26 patients identified with spontaneous encephalocele with CSF leak, 9 patients had postoperative lumbar puncture data. Of those 9, 89% were female subjects, and 11% were male, with a mean age of 57 and a mean BMI of 41 kg/m2 (morbidly obese). The mean opening pressure was 24.5 cm H2O. Approximately 33% had normal intracranial pressure (mean, 15 cm H2O; range, 10–17 cm H2O); 67% had elevated intracranial pressure (mean, 29 cm H2O; range, 23.5–40 cm H2O). The incidence of BIH in the general population is 0.001%. Of the 6 with intracranial hypertension, 3 (50%) were placed on acetazolamide for fundoscopic findings, postoperative headache, and/or visual changes. Mean time to LP after repair of encephalocele was 13 months (range, 4 days to 75 months). Conclusion This study shows that benign intracranial hypertension is prevalent in a significant number of patients presenting with spontaneous encephalocele with CSF otorrhea at a rate much higher than is found in the general population. This finding has direct clinical implications and suggests that all patients with spontaneous encephalocele/CSF leak warrant evaluation for benign intracranial hypertension.

Ossicular chain reconstruction: titanium versus plastipore.

Objective: To compare the complication rate and hearing results of a new, lightweight, titanium ossicular replacement prosthesis with Plastipore prostheses (Xomed, Jacksonville, FL). Study Design: Retrospective. Methods: Charts were reviewed for type of operation, type of prosthesis used, extrusion rate, prostheses failure rate, and hearing thresholds at multiple frequencies and at multiple follow‐up points. The dependant variable for hearing results was the four‐frequency average air‐bone gap. Results: There were 84 patients undergoing tympanoplasty with the Plastipore prosthesis and 53 with the titanium. There was one extrusion in the titanium group. There was an additional single incidence of prosthesis failure in the titanium group. Overall hearing results were comparable with an air‐bone gap average of 19.3 dB in the Plastipore group compared with the titanium group with an air‐bone gap of 22.0 dB (P = .08). Sixty percent of patients had a postoperative air‐bone gap of 20 dB or less in the Plastipore group. In the titanium group, 45.3% achieved a 20 dB or less postoperative air‐bone gap. Plastipore had a lower air‐bone gap than the titanium when a canal wall up operation was performed (17.8 vs. 23.9 dB) and tended toward a lower air‐bone gap when a total ossicular prosthesis was needed (22 vs. 27 dB) (P < .07). Conclusion: The titanium prosthesis is a new ossicular replacement prosthesis that provides excellent visualization during insertion and provides hearing results that are comparable with Plastipore. The Plastipore prosthesis performed better in canal wall up mastoidectomy situations and tended toward better performance when a total ossicular replacement prosthesis was needed.

Facial nerve function and hearing preservation acoustic tumor surgery: Does the approach matter?

OBJECTIVE: The retrosigmoid and middle fossa approaches to acoustic tumor excision allow for hearing preservation but differ in the angle of approach to the facial nerve. The authors comparatively examined facial nerve results of each approach. STUDY DESIGN: Case series with chart review. SETTING: Multiple physician subspecialty practice. SUBJECTS AND METHODS: The authors reviewed facial nerve outcomes of patients undergoing acoustic tumor excision at a single subspecialty practice that had used a hearing preservation approach for the past 15 years. The retrosigmoid and middle fossa approaches were compared. Hearing results and recurrence rates were also examined. RESULTS: One hundred thirty-eight patients had adequate data for inclusion in this study. Of the patients undergoing a middle fossa approach, 80 percent had a House-Brackmann (HB) grade I-II outcome, whereas 90 percent of patients undergoing the retrosigmoid approach had an HB grade I-II. When classifying HB I and II outcomes together, we did not find a statistically different result between the surgical groups. Upon more critical analysis, however, facial function recovered faster and there were more long-term HB grade I function results in the retrosigmoid group. There were more recurrent/residual tumors in the retrosigmoid group and better hearing preservation in the middle fossa group. CONCLUSION: There are small but important functional outcome differences between the retrosigmoid and middle fossa approach for acoustic tumors. The clinician needs a working understanding of these differences so that the correct approach can be used to produce the best results for each patient.

Stapedectomy in Congenital Stapes Fixation: Are Hearing Outcomes Poorer?

OBJECTIVE: To evaluate outcomes of stapedectomy surgery for congenital stapes fixation. STUDY DESIGN: Retrospective chart review. METHODS: The charts of 463 stapedectomies performed by 1 surgeon from 1996 to 2003 were reviewed. Patients with a history of childhood hearing loss and operative findings consistent with congenital fixation of the stapes were included. Patients with a history of trauma or chronic otitis media and those with otosclerosis were excluded. Thirty-six patients underwent stapedectomy for congenital fixation. Revision cases and those with inadequate postoperative bone or air conduction data were excluded. Inclusion criteria were met for 25 patients. Operative findings and hearing outcomes were evaluated. RESULTS: The study group was comprised of 25 stapedectomies. Closure of the air-bone gap to less than 10 dB was achieved in 48% of cases, and 80% had closure within 20 dB. A gap of more than 30 dB remained in 3 cases. There were 2 cases of sensorineural hearing loss with worsening of the bone conduction thresholds by 15 dB and 30 dB. There were no instances of perilymph gusher. In addition to an excluded case that was not reconstructed because of facial nerve position, 3 of the included patients were found to have a dehiscent facial nerve at surgery. There were no facial nerve injuries, and fixation of the malleus or incus was not found in any of the included patients. When hearing outcomes were compared with our results for otosclerosis over the same time period, rates of closure to within 10 dB and 20 dB were significantly worse in the congenital group. CONCLUSION: Closure of the air-bone gap in this population differs from our results in stapedectomy done for otosclerosis. This difference likely reflects subtle anatomic variations in the congenital group that affect the effectiveness of the prosthesis. Despite the difference in results, stapedectomy for congenital fixation remains an effective method to achieve significant hearing improvement in the majority of patients. EBM rating: B-3b

The comparative risks of bacterial contamination between a venturi atomizer and a positive displacement atomizer.

Introduction This laboratory study determined the incidence of internal contamination of Venturi principle atomizers and positive displacement atomizers exposed to high external concentrations of Staphylococcal aureus (Staph). Methods Atomizer device nozzle tips were immersed into a Staph solution and 1 ml of spray was atomized via compressed wall air (Venturi) or hydraulic pump (positive displacement). The Venturi nozzle was then wiped with 70% isopropyl alcohol while the disposable positive displacement nozzle was replaced. After 30 minutes, 1 ml of atomized fluid was collected and cultured and the process was repeated. After sixteen uses the fluid remaining in the bottles was cultured. The Venturi atomizer also was subjected to a single use trial to determine the location of device contamination. Results Venturi atomizers sprays grew Staph in every case (144/144), while positive displacement atomizer sprays never grew contaminants (0/144; p < 0.0001). At the end of 16 uses, 7/9 of Venturi atomizers had Staph within their medication reservoirs while none (0/9; p = 0.002) existed in the positive displacement atomizers. After a single use of the Venturi atomizer, the medication reservoir, the air lumen and the medication lumen of the nozzle were all contaminated with Staph. Conclusions External bacterial contamination of the atomizer nozzle tip results in internal bacterial contamination of Venturi devices in as little as one use but not of positive displacement devices. These results warrant further investigation to determine whether a risk of cross-contamination exists in a clinical setting.

Patterns of failure in heat-activated crimping prosthesis in stapedotomy.

Objective: To understand potential causes of failure in heat-activated crimping prosthesis in stapedotomy. Study Design: Retrospective chart review of all primary and subsequent revision stapedotomy operations performed by the senior authors with heat-activated-crimping prosthesis between June 2003 and September 2009. Patients who had history of previous stapedotomy performed elsewhere were excluded. Setting: Private neurotologic tertiary referral center. Patients: The 335 primary stapedotomies reviewed included 190 with a SMart prosthesis and 145 with a manual-crimp De La Cruz prothesis. Twenty-one patients in the SMart prosthesis group underwent revision stapedotomy. Six patients in the De La Cruz prosthesis group underwent revision stapedotomy. Average length of time between initial and revision surgery for each prosthetic group was 16.5 months and 11 months, respectively. Intervention: Primary and revision stapedotomy using heat-activated nitinol (SMart) or manual crimp-on platinum (De La Cruz) prosthesis. Results: A total of 190 primary stapedotomies using heat-activated crimping prosthesis were performed between this period. There were 21 patients who had initial good hearing results that required revision or replacement with a different type of prosthesis. A common finding was lateral displacement of the prosthesis from the stapedotomy with detachment of the nitinol hook from the incus. This group of patients was compared with a control group that used manual-crimp prosthesis. Conclusion: Heat-activated crimping prosthesis has been reported to enhance stapedotomy hearing outcomes on short- and long-term follow-up studies. Longitudinal analysis on its complications has not been reported. This case series demonstrated 11% rate of possible lateral displacement of the prosthesis out of the vestibule and/or incus. Reopening of the nitinol hook off the incus also was a common associated finding. Failure rates are classified. The advantages and disadvantages of this popular prosthesis are reviewed.