Hearing outcome after concurrent endolymphatic shunt and vestibular nerve section.

OBJECTIVE: To determine if endolymphatic shunt surgery concurrent with vestibular nerve section improves hearing outcome compared with vestibular nerve section alone. STUDY DESIGN: Retrospective observational study with cross-sectional survey. SETTING: Tertiary otologic private practice. PATIENTS: Thirty-five patients who underwent vestibular nerve section and endolymphatic shunt surgery and 17 patients who had vestibular nerve section alone between 1985 and 2000. METHODS: Chart review and correspondence for audiogram results and survey. MAIN OUTCOME MEASURES: Hearing at last follow-up. Hearing Handicap Inventory, Dizziness Handicap Inventory, Tinnitus Handicap Inventory, and SF-36. RESULTS: Eight patients in the vestibular nerve section and 15 in the vestibular nerve section and endolymphatic shunt surgery group had an audiogram at more than 16 months after surgery available for review. In the vestibular nerve section group, three patients had same hearing whereas five were worse. In the vestibular nerve section and endolymphatic shunt surgery group, 2 patients showed improvement, 2 were the same, and 11 were worse. There was no significant difference in the change from preoperative pure tone average or Word Discrimination Score to postoperative levels between the surgical groups. Eighteen patients had serviceable hearing preoperatively. Five of 8 in the vestibular nerve section and 4 of 10 in the vestibular nerve section and endolymphatic shunt surgery groups maintained serviceable hearing postoperatively. Of the 52 patients, 33 responded to the survey (63%). There were no significant differences between the groups for Dizziness Handicap Inventory, Hearing Handicap Inventory, Tinnitus Handicap Inventory, or SF-36, suggesting that patient-oriented outcomes are the same in both groups. CONCLUSIONS: Concurrent endolymphatic shunt surgery and vestibular nerve section does not improve hearing or tinnitus outcome over vestibular nerve section alone.

Medical devices; ear, nose and throat devices; reclassification of the endolymphatic shunt tube with valve. Final rule.

The Food and Drug Administration (FDA) is reclassifying the endolymphatic shunt tube with valve from class III (premarket approval) into class II (special controls). The device is intended to be implanted in the inner ear to relieve the symptoms of vertigo and hearing loss due to endolymphatic hydrops (increase in endolymphatic fluid) of Meniere's disease. FDA is also identifying the guidance document entitled "Class II Special Controls Guidance Document: Endolymphatic Shunt Tube With Valve; Guidance for Industry and FDA" (the guidance) as the special control that the agency believes will reasonably ensure the safety and effectiveness of the device. This reclassification is based on new information submitted in are classification petition by E. Benson Hood Laboratories, Inc. (Hood Laboratories). FDA is taking this action under the Federal Food, Drug, and Cosmetic Act (the act), as amended by the Medical Device Amendments of 1976, the Safe Medical Devices Act of 1990, and the Food and Drug Administration Modernization Act of 1997. Elsewhere in this issue of the Federal Register, FDA is publishing a notice announcing the guidance.

Endolymphatic subarachnoid shunt failure caused by Silastic allergy.

During the period from 1964 through 1994, the endolymphatic subarachnoid shunt operation was initially successful in eliminating endolymphatic hydrops and the symptoms and findings it produces in 76% of 645 ears of patients with Meniere's disease. After initial success, lasting from five weeks to nine years, endolymphatic hydrops suddenly returned due to obstruction of the Silastic shunt tube in 11% of patients. In these cases, prompt revision can often restore an initial good result. Histologic and immunologic examination of the material surrounding and occluding the tubes showed an allergic response to the Silastic material in most instances. Efforts to eliminate this cause of failure using a tube of new design and different plastic material are described.

Histologic and ultrastructural features of explanted Arenberg shunts.

Four Arenberg endolymphatic shunts that had been implanted in patients for 6 years, 3 years, 24 months, and 11 months were removed during retrolabyrinthine nerve sections (two cases), labyrinthectomy (one case), or cochlear implant (one case). The shunts were examined and photographed grossly and the components were prepared for light and scanning electron microscopy. Acellular debris filled the vestibule around the valve in all cases. The same material filled the inside of the valve in two cases and could be seen coming through the valve in two cases. Two shunts had ingrowth of fibrous tissue into the sponge. The finding of greatest concern was multiple erosions seen in the Supramid tube (S. Jackson Inc, Alexandria, Va) that inserts into the endolymphatic sac. On scanning electron microscopy, these erosions appeared as a network of cracks in the outer surface of the tube. The two shunts implanted for the longest time had fenestrae completely through the tube wall. These findings question the long-term functioning and integrity of the Arenberg shunt.