Silicone allergy: A new cause for cochlear implant extrusion and its management.

OBJECTIVE: We introduce silicone allergy as a rare cause for cochlear implant extrusion and discuss its management. STUDY DESIGN: Retrospective case series and literature review. SETTING: Tertiary referral centers. PATIENTS: Primary eligibility criteria included patients who experienced a delayed extrusion of their cochlear implants with negative wound cultures and had a suspected or a test-proven allergy to silicone components of an implant. INTERVENTIONS: Silicone allergy testing, explantation of a cochlear implant containing allergenic silicone materials, reimplantation with a custom-made cochlear implant excluding an allergenic silicone component. OUTCOME MEASURES: Uneventful wound healing and extrusion-free long-term follow-up after the reimplantation with a custom-made cochlear implant excluding an allergenic silicone component. RESULTS: Three known cases of cochlear implant extrusion as a result of silicone allergy have been noted from 1991 through 2004 in three cochlear implant programs in the United States. All three devices extruded, resulting in explantation of the old device and reimplantation with a new custom-made device eliminating the allergenic silicone component. Wound cultures were negative in all cases. All three patients experienced a delayed extrusion of their devices. Two of these patients had a test-proven allergy to the implant's silicone components, whereas the third patient was presumed to have a hypersensitivity solely on the basis of a clinical presentation. CONCLUSION: We propose that silicone allergy is a rare cause of cochlear implant extrusion. Patients experiencing cochlear implant extrusion, particularly with a delayed onset and negative wound culture results, should be tested for silicone allergy.

Modifications of standard cochlear implantation techniques for children under 18 months of age.

Cochlear implantation is being performed in increasingly younger children. We present a retrospective cohort of 19 patients with 23 ears implanted under 18 months of age. The mean age at implantation was 11.9 months, with the youngest being 6.8 months. The facial recess was narrow in nine ears (39%), including all premature infants. An inferiorly located stapedius tendon was sectioned in seven ears (30%) to facilitate round window access. Countersinking of the receiver-stimulator required dural exposure in 22 ears (96%). The receiver-stimulator was secured with sutures in 15 ears (65%) and within a tight pocket in eight ears (35%). Tympanostomy tubes were placed in 10 ears (43%). Cochlear implantation in very young children frequently necessitates modified surgical techniques.

Malleus-to-footplate ossicular reconstruction prosthesis positioning: cochleovestibular pressure optimization.

AIMS: To determine 1) the best position for hydroxylapatite malleus-to-footplate (MFP), ossicular replacement prosthesis (ORP) in reconstructed ears, and 2) whether preserving the stapes superstructure (SS), when present, has acoustic advantages. BACKGROUND: Positioning of the MFP-ORP head beneath the neck of the malleus may produce maximal force, whereas positioning beneath the manubrium of the malleus may produce the greatest displacement. It is not clear which is the optimal placement position. In addition, we look at the effect of the SS on sound transmission to the inner ear in ossicular reconstruction. METHODS: The ear-canal air pressure and vestibular hydro-pressure were measured in human cadaver temporal bones with incus intact, removed, and replaced with the MFP-ORP; the ORP head was placed at three different positions on the malleus (head, mid-manubrium, and umbo) while keeping its base at the center of stapes footplate with intact or removed stapes SS. The vestibular pressure ratio between the ear with intact incus and MFP-ORP reconstructed ear is defined as Lmfp, the loss caused by the prosthesis in relation to the normal ossicular chain. RESULTS: The mean magnitude of Lmfp, averaged in the important speech frequency region of 0.5 to 3 kHz, is approximately 7.8 dB at the neck with stapes SS. In comparison, mean magnitude of Lmfp for mid-manubrium without stapes SS is 15 dB (p = 0.04), and with the stapes SS it is 16 dB (p = 0.05), whereas at the umbo without SS it is 15 dB (p = 0.03). In the 8 kHz region, the mean magnitude of Lmfp is approximately 1 dB with the stapes SS intact and approximately 8.5 dB when it was removed (p < 0.09). CONCLUSION: There are significant physiologic advantages to placing the hydroxylapatite MFP-ORP beneath the neck of the malleus and preserving the SS.

Minimally invasive tongue base surgery for obstructive sleep apnoea.

Moderate to severe obstructive sleep apnoea is usually associated with multiple levels of pharyngeal airway collapse, including tongue base obstruction. A new technique has recently been introduced that improves the nocturnal retro-lingual airway. This study was a prospective, non-randomized single-institution evaluation of a recently introduced surgical technique. Nineteen consecutive patients with previously untreated moderate to severe obstructive sleep apnoea underwent tongue suspension using the Respose system and concomitant palatopharyngoplasty (multilevel pharyngeal surgery). The patient demographics and treatment outcomes were prospectively collected and retrospectively analysed. There were 16 men and three women, with a mean (+/-SD) age of 44.9 years (+/- 14.2) and a mean pre-operative apnoea-hypopnoea index (AHI) of 42.8 +/- 24.8. Twelve of the 19 patients (63.2 per cent) have had post-operative polysomnography; eight of these 12 (67 per cent) met the standard criteria for surgical response. Among these eight patients, the AHI improved from 32.4 to 14.4 (p<0.01); the individual scores fell by a mean of 51.7 per cent. The apnoea index improved from 7.4 to 0.9 (p<0.01), with the individual scores falling by a mean of 81.4 per cent. There was anatomic and radiographic evidence of multilevel upper airway enlargement. Notably, the body mass index remained essentially unchanged (31.5 +/- 7.2 to 31.2 +/- 7.6, p>0.5). Subjectively, the mean Epworth sleepiness scale score fell from 11.0 +/- 5.4 to 5.4 +/- 3.8 (p<0.005). Four patients suffered transient velopharyngeal insufficiency, and two patients complained of limited anterior excursion of the tongue. There were no serious, long-term complications. The tongue suspension procedure represents a minimally invasive technique for improving the nocturnal retro-lingual airway in patients with obstructive sleep apnoea. It is easily performed by otolaryngologists, distinguishing it from other established techniques designed to address tongue base obstruction.