Surgical anatomy of Crista fenestra of round window corridor in relation
to cochlear implantation: Our experience in 140 cases
Objective: This study is to describe surgical morphological types of the
crista fenestra (CF) in relation to round window membrane (RWM) and to
determine its impact on cochlear implant (CI) via the RW insertion.
Materials and Methods: A series of 140 cases of CI which were performed
in tertiary referral centers for CI with intra-operative video
recording. Two senior CI surgeons reviewed these recordings for
detection of morphological classification. Results: 125 cases (89.28%)
showed the type (A) CF, which sub-classified to: Type A-1 in 93 cases
(66.42%), type A-2 in 26 cases (18.57%) and type A-3 in 6 cases
(4.28%) Type (B) CF was detected in 15 cases, which sub-classified to:
Type B-1 in 11 cases (7.85%) and type B-2 in 4 cases (2.85%).
Conclusion: In spite of large morphological diversity, Crist Fenestra
can be classified into two main types. Most of them were no need for its
removal whereas in a minority of the cases it hinders electrode
insertion and needs drilling. KEYWORDS: Cochlear implant, round window
membrane, Crista fenestra, drilling.