Cochlear Obliteration after Translabyrinthine Resection for Large Cerebellopontine Angle Tumor

Abstract

<b><i>Introduction:</i></b> The aim of this study was to better understand the onset time and factors associated with cochlear obliteration following translabyrinthine approach (TLA) surgery for large cerebellopontine angle tumors. <b><i>Methods:</i></b> This retrospective cohort study included 117 patients with large cerebellopontine angle tumor (tumor diameter >2 cm) treated by TLA surgery from June 2011 to March 2019 in a single tertiary referral center. The Kaplan-Meier method with log-rank test was used to estimate cochlear patency survival and the association between survival and covariates, and the Cox proportional hazards regression analysis was used to identify possible factors associated with cochlear obliteration. <b><i>Results:</i></b> Of the 117 patients included in our analysis, the median follow-up was 24.8 months. There were 30 (25.6%) patients in the cochlear obliteration group, and 87 (74.4%) in the patent cochlear group. Various degrees of cochlear obliteration was found in 25.6% patients in final MRI scan, comprised of 50% grade I, 30% grade II, and 20% grade III. Cochlear patency survival curves showed 94.0% at 3 months, 73.0% at 18 months, which plateaued after 20 months with a survival rate of 71.6%. In the multivariate Cox proportional hazards model, patients presented with postoperative hyperintense T1W cochlear signal had poorer cochlear patency survival compared to isointense T1W (HR = 4.15). Similarly, postoperative deteriorated facial function (HR = 4.52) and full IAC involvement of tumor (HR = 2.33) demonstrated a higher risks of cochlear obliteration after TLA surgery. <b><i>Conclusion:</i></b> The 2-year estimated cochlear patency rate was 71.6% in patients that received TLA. Cochlear obliteration can develop as early as 3 months post-surgery, with no new obliteration 20 months after the surgery and half of these patients got severe obliteration. Three factors associated with cochlear obliteration were identified including full IAC involvement of tumor, postoperative facial function deterioration, and postoperative hyperintense T1W cochlear signal.

Vestibularisschwannom: Faktoren bei der Therapieentscheidung

“…Erfolgt die CI-Versorgung nicht simultan, so empfiehlt sich fast immer die Einlage eines intracochleären Platzhalters im Rahmen der translabyrinthären VS-Operation, um einer cochleären Obliteration vorzubeugen und sich für die Zukunft die Chance auf eine CI-Versorgung zumindest offen zu halten. Cochleäre Ossifikationen sind bereits wenige Wochen nach VS-Operation beschrieben [117], und etwa 40% aller MRT-Kontrollen innerhalb eines Jahres nach VS-Operation zeigen Anzeichen für eine Ossifikation [118].…”