William M. Luxford

The narrow internal auditory canal in children: A contraindication to cochlear implants

We suggest a new explanation for the lack of auditory response to electric stimulation in children with cochlear implants: The very narrow internal auditory canal, 1 to 2 mm in diameter, and the probable absence of the cochlear nerve. This defect can be seen on high-resolution computed tomographic x-ray studies and may represent aplasia of the auditory-vestibular nerve. We report on eight children with this anomaly, three of whom have received implants and failed to respond with a sensation of sound. Identification of this problem on screening x-ray films is a contraindication to cochlear Implantation for auditory stimulation.

TORPs and PORPs in tympanoplasty: a review of 1042 operations.

We reviewed 1042 operations in which a Plasti-Pore prosthesis was used for reconstruction of the sound pressure transfer mechanism. In all cases cartilage was interposed between the prosthesis and the tympanic membrane or graft. The short-term hearing results for these cases are the same as for other techniques but the hearing is more stable in the long run. Other advantages of this technique are a reduced incidence of recurrent and residual cholesteatoma. Extrusion occurred in 7% of the cases but has become less frequent with recent refinements in technique. We intend to continue using Plasti-Pore prostheses in tympanoplasty.

Postoperative Infection in Cochlear Implant Patients

OBJECTIVE: Recently, the association of meningitis with cochlear implants has raised concern over the safety of these devices. We examined the incidence of all postoperative infections in patients undergoing cochlear implant surgery. STUDY DESIGN AND SETTINGS: A retrospective chart review of all patients undergoing cochlear implants at a private tertiary referral center from 1993 to 2002 was performed. Cochlear implant surgeries in 462 adults and 271 children were reviewed. Patients with evidence of a postoperative infection or infectious complication related to cochlear implantation were identified, and data on patient characteristics, surgery, and treatment outcome were obtained. RESULTS: The overall incidence of postoperative infection in our cochlear implant series was 4.1%. Major infectious complications occurred in 3.0% of cases, and the majority of infections required surgical intervention. A history of chronic ear disease may increase the risk of infectious complications. There were no cases of meningitis. CONCLUSIONS: Cochlear implants remain a safe procedure with a low complication rate. The majority of infections can be managed without removing the implant device. Advances in surgical technique and flap design have decreased the occurrence of wound-related complications. However, identification of risk factors for infection and optimization of treatment regimens will further reduce the complications associated with postoperative infection.

Cochlear patency problems in cochlear implantation

Sensory deafness may be associated with partial or total obliteration of the cochlear scalae. Before undertaking cochlear implant surgery, a preoperative assessment of cochlear patency with high‐resolution computed tomography (CT) is indicated. To determine the accuracy of pre‐implant CT, a review of the radiographic and surgical findings in 36 implanted ears was performed. An abnormal CT scan was found to be a reliable predictor of compromised cochlear patency at operation. These findings help the surgeon to select the side most favorable for implantation and to anticipate problems that may be encountered during device insertion. A normal pre‐implant CT scan, however, does not exclude the possibility of compromised cochlear patency. A 46% false negative rate was encountered, presumably because subtle degrees of osseous or fibrous obliteration of the cochlea are beyond the resolution by current generation CT scanners.

A temporal bone study of insertion trauma and intracochlear position of cochlear implant electrodes. I: Comparison of Nucleus banded and Nucleus Contour electrodes.

In recent years, new designs of cochlear implant electrodes have been introduced in an attempt to improve efficiency and performance by locating stimulation sites closer to spiral ganglion neurons and deeper into the scala tympani. The goal of this study was to document insertion depth, intracochlear position and insertion trauma with the Nucleus Contour electrode and to compare results to those observed with the earlier generation Nucleus banded electrode. For this comparison eight Nuclears banded electrodes and 18 Contour electrodes were implanted in cadaver temporal bones using a realistic surgical exposure. Two experienced cochlear implant surgeons and two otology fellows with specialized training in cochlear implant surgery were selected for the study to represent a range of surgical experience similar to that of surgeons currently performing the procedure throughout the world. Following insertion of the electrodes, specimens were imaged using plain film X-ray, embedded in acrylic resin, cut in radial sections with the electrodes in place, and each cut surface was polished. Insertion depth was measured in digitized X-ray images, and trauma was assessed in each cross-section. The Contour electrode inserted more deeply (mean depth=17.9 mm or 417 degrees ) than the banded electrode (mean depth=15.3 mm or 285 degrees ). The incidence and severity of trauma varied substantially among the temporal bones studied. However, the nature and frequency of injuries observed with the two devices were very similar. The Contour electrode was clearly positioned closer to the modiolus than the banded model, and also appeared easier to use. Based on this difference in position and data from previous studies we conclude that the Contour electrode may provide lower thresholds and improved channel selectivity, but the incidence of trauma remains a problem with the newer design. The relative influences of electrode positioning and neural degeneration that may result from trauma are as yet unclear.

Sudden bilateral sensorineural hearing loss.

Most cases of sudden sensorineural hearing loss (SHL) remain idiopathic, and the majority are unilateral. From 1989 to 1993, 823 patients with sudden SHL were evaluated. Of these, 14 (1.7%) had sudden bilateral SHL. We reviewed the charts of these 14 patients to compare sudden bilateral SHL with sudden unilateral SHL. Usually, bilateral SHL was asymmetric. Most bilateral cases received combined steroid and vasodilator treatment, while unilateral cases were more likely to receive only one of these treatments. By audiological criteria, 67% of bilateral SHL cases improved, while the improvement rate in unilateral SHL was 52%; however, this difference was not statistically significant. In bilateral SHL patients showing improvement, both ears responded. Bilateral SHL patients were older at the onset of hearing loss, had a higher incidence of vascular disease, and were more likely to have positive antinuclear antibody titer. Recognition of similarities and differences between sudden unilateral and bilateral SHL can help in counseling patients.

A temporal bone study of insertion trauma and intracochlear position of cochlear implant electrodes. II: Comparison of Spiral Clarion™ and HiFocus II™ electrodes

In recent years, several new designs of cochlear implant electrodes have been introduced clinically with the goal of optimizing perimodiolar placement of stimulation sites. Previous studies suggest that perimodiolar electrodes may increase both the efficiency and performance of a cochlear implant. This is the second of two studies designed to examine the positioning of electrodes and the occurrence of insertion-related injury with these newer designs and to directly compare two perimodiolar electrodes to their predecessors. In our previous report we compared the Nucleus banded electrode with the Nucleus Contour perimodiolar electrode. In the present study, using the same protocol, we examine the Spiral Clarion electrode and its successor, the HiFocus II electrode with attached positioner. Eight Spiral Clarion arrays and 20 HiFocus II electrodes with positioners were inserted into human cadaver temporal bones. Following insertion, the specimens were embedded in acrylic resin, cut in quarters with a diamond saw and polished. Insertion depth, proximity to the modiolus and trauma were evaluated in X-ray images and light microscopy. The newer electrode was consistently positioned closer to the modiolus than the previous device whereas the angular depth of insertion measured for the two electrodes was similar. The incidence of trauma was minimal when either electrode was inserted to a depth of less than 400 degrees . However, severe trauma was observed in every case in which the HiFocus II with positioner was inserted beyond 400 degrees and in some cases in which the Spiral Clarion was inserted beyond 400 degrees . To evaluate the possible role of electrode size in the trauma observed we modeled both devices relative to the dimensions of the scala tympani. We found that the fully inserted HiFocus II electrode with positioner was larger than the scala tympani in approximately 70% of temporal bones measured. The results suggest that both the Clarion spiral and HiFocus II with positioner can be inserted with minimal trauma, but in many cases not to the maximum depth allowed by the design.

Revision cochlear implant surgery in children.

Objective: To determine the incidence of revision cochlear implant (CI) surgery in children and the indications for revision surgery and to examine the pattern of events that lead to revision CI surgery. Study Design: Retrospective case review. Setting: Two tertiary pediatric CI centers. Patients: Pediatric CI patients who underwent revision surgery related to their CI. Main Outcome Measures: Reasons for revision, surgical outcomes, complications, performance, and device analyses were sought. Results: Nine hundred fifty-two pediatric CI operations were performed between 1991 and 2005. Ninety-three patients underwent 107 (11.2%) revision operations. Hard device failure occurred in 46% (n = 49); soft failure occurred in 15% (n = 16); medical/surgical causes were responsible for 37% (n = 40); and magnet dislodgement requiring revision surgery occurred in 2% (n = 2). Head trauma was associated with 41% of the hard failure cases (n = 20). Device analyses revealed identifiable abnormalities in most of both hard and soft failure cases. In most patients, auditory performance equaled or surpassed the best preoperative performance by 6 to 12 months after revision. Conclusion: Revision CI surgery is common among pediatric CI recipients. Hard failure is the most common reason for undertaking revision surgery, and this mode of failure is frequently associated with preceding head trauma. Patients and parents should be counseled that performance is expected to equal or surpass the childs best level of performance before revision surgery, although this may take some time, and exceptions do exist.

Cochlear implant soft failures consensus development conference statement

COCHLEAR IMPLANT SOFT FAILURES CONSENSUS DEVELOPMENT CONFERENCE STATEMENTThis Consensus Statement was prepared by a panel of experts representing the fields of otolaryngology, audiology, speech and language pathology, communication science, and engineering. Representatives to the conference were app

Congenital atresia of the external auditory canal.

Children with congenital atresia of the external auditory canal require an early assessment of hearing and a determination of the degree of atresia and associated pathology by polytomography and/or high‐resolution CT scanning.