Journal Article

Novel Method of Measuring Canal Dehiscence and Evaluation of its Potential as a Predictor of Symptom Outcomes After Middle Fossa Craniotomy

Voth, Brittany L, Gaonkar, Bilwaj, Beckett, Joel S, Chung, Lawrance K, Lagman, Carlito, Yang, Isaac, Chen, Cheng Hao Jacky, Gopen, Quinton

2018

Overview

Abstract BACKGROUND Superior semicircular canal dehiscence (SSCD) is an osseous defect of the arcuate eminence of the petrous temporal bone. Strategies for measuring dehiscence size are variable, and the usefulness of such parameters remains in clinical equipoise. OBJECTIVE To present a novel method of measuring dehiscence volume and to evaluate its potential as a predictor of symptom outcomes after surgical repair of SSCD. METHODS High-resolution computed tomographic temporal bone images were imported into a freely available segmentation software. Dehiscence lengths and volumes were ascertained by independent authors. Inter-rater observer reliability was assessed using Cronbach's alpha. Correlation and regression analyses were performed to evaluate for relationships between dehiscence size and symptoms (pre- and post-operative). RESULTS Thirty-seven dehiscences were segmented using the novel volumetric assessment. Cronbach's alpha for dehiscence lengths and volumes were 0.97 and 0.95, respectively. Dehiscence lengths were more variable as compared to dehiscence volumes (σ2 8.92 vs σ2 0.55, F = 1.74). The mean dehiscence volume was 2.22 mm3 (0.74, 0.64-0.53 mm3). Dehiscence volume and headache at presentation were positively correlated (Rpb = 0.67, P = .03). Dehiscence volume and vertigo improvement after surgery were positively correlated, although this did not reach statistical significance (Rpb = 0.46, P = .21). CONCLUSION SSCD volumetry is a novel method of measuring dehiscence size that has excellent inter-rater reliability and is less variable compared to dehiscence length, but its potential as a predictor of symptom outcomes is not substantiated. However, the study is limited by low power.

• Publisher: Oxford University Press,Copyright by the Congress of Neurological Surgeons,Wolters Kluwer Health, Inc
• Subject: Adult / Age / Aged / Aged, 80 and over / Craniotomy - methods / Female / Headaches / Hearing loss / Humans / Male / Medicine / Middle Aged / Neurosurgery / Patients / Reproducibility of Results / Retrospective Studies / Semicircular Canals - diagnostic imaging / Semicircular Canals - pathology / Semicircular Canals - surgery / Software / Surgeons / Surgery / Surgical outcomes / Surgical techniques / Temporal Bone - surgery / Tinnitus / Tomography, X-Ray Computed / Vertigo / Young Adult