Extended Retrolabyrinthine Approach: Results of Hearing Preservation Surgery Using a New System for Continuous Near Real-time Neuromonitoring in Patients With Growing Vestibular Schwannomas.

OBJECTIVE: To report hearing preservation results after retrolabyrinthine vestibular schwannoma surgery, using a new system for continuous near real-time monitoring of cochlear nerve function. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center, University Hospital. PATIENTS: Thirty-one consecutive patients with growing vestibular schwannomas and opting for hearing preservation surgery. INTERVENTIONS: Tumor removal by a modified, extended retrolabyrinthine approach, using a new system for continuous near real-time monitoring of cochlear nerve function. MAIN OUTCOME MEASURES: Pure-tone average and speech discrimination (SD) 1-year postoperative. Preservation of word recognition score class. Preservation of serviceable hearing (SD>50%). RESULTS: Any hearing was preserved in 83 and 69% had preserved word recognition score class or better. Serviceable hearing was preserved in 77%. SD was unchanged in 48%, improved in 21%, and poorer in 31%. Of 18 patients with potential for improvement (SD 90% or worse preoperatively), 33% improved (SD increase 10% or more). CONCLUSION: The hearing preservation rate is favorable using the modified, extended retrolabyrinthine approach and a new system for continuous near real-time monitoring of cochlear nerve function for removal of growing vestibular schwannomas, as 77% preserved serviceable hearing 1 year after surgery. Hearing improved after surgery in 33%. Using the new neuromonitoring system, serviceable hearing preservation rate improved from 53 to 77% at our center.

[Workup and treatment of vestibular schwannomas].

Vestibular schwannomas are benign tumours originating from the eighth cranial nerve. The incidence in Denmark is rising and is around 200 per million per year. Pure tone audiometry, discrimination score and tinnitus anamnesis determine, whether a diagnostic MRI is merited. Around one fourth of newly diagnosed patients receive surgery due to the size of the tumour, whereas the remaining three fourths go into a "wait-and-scan" regime. 30-40% of the patients in this regime experience growth and are offered either surgery or radiotherapy.

Innate immune defense in the inner ear - mucines are expressed by the human endolymphatic sac.

The human endolymphatic sac has been shown recently to have immunological capacities and has thus been proposed as the main entity protecting the inner ear from pathogen invasion, equivalent to mucosa-associated lymphoid tissue (MALT). Although the sac expresses molecules of the innate immune system, the potential expression of members of the important mucin family has not been detailed. Thus, this paper explores endolymphatic sac expression of a number of mucins and mucin precursors. Twelve fresh tissue samples from the human endolymphatic sac were obtained during translabyrinthine surgery. The expression of Mucin 1, 2, 5B/AC and 16, as well as the core structure elements (mucin precursors) T-antigen, Tn-antigen and Sialyl-Tn-antigen was investigated by immunohistochemistry. The endolymphatic sac epithelium expressed MUC1 (both apically towards the endolymphatic sac (ES) lumen and basally towards the capillary network), MUC 16 and Tn-antigen. There was no labeling after incubation with antibodies against T-antigen, sialyl-Tn-antigen, MUC2 and MUC5B/AC. We conclude that the human endolymphatic sac epithelium expresses a number of mucin molecules, which supports the hypothesis of the sac as the primary immunological tissue structure of the inner ear, equivalent to MALT in other organs. The mucins may also play a role in the formation and continuous homeostasis of the inner ear fluids, as well as the pathogenesis of Meniere's disease.

Clinical Outcome of a Wide-diameter Bone-anchored Hearing Implant and a Surgical Technique With Tissue Preservation.

OBJECTIVE: To investigate the clinical outcome of a surgical technique with tissue preservation for a wide bone-anchored hearing implant concerning postoperative complications, skin reactions, implant loss, and implant stability. STUDY DESIGN: Consecutive, prospective case series. SETTING: Tertiary referral center. PATIENTS: Twenty-four adult patients with normal skin quality were enrolled. INTERVENTION(S): Implantation of bone-anchored implant was performed using a one-stage linear-incision technique with tissue preservation surgery. MAIN OUTCOME MEASURES(S): Skin and soft tissue reactions according to Holgers grading system. Pain and numbness measured according to visual analogue scale. Implant stability quotient values were recorded using resonance frequency analysis. Follow-up at 10 days, 6 weeks, 6 months, and 1 year after surgery. RESULTS: Primary implant stability was good and a significant increase in implant stability quotient occurred during the first 10 days and continued to be stable throughout the 1-year observation period. No implants were lost. Skin and soft tissue reactions were few, no reaction (Holger grade 0) was observed in 88% of the follow-up examinations and no grade 4 reactions occurred. Pain and numbness were minimal. CONCLUSION: The wide implant showed good stability initially and throughout the observation period. Skin and soft tissue reactions were rare and minor. No implants were lost.