Evaluating cochlear insertion trauma and hearing preservation after cochlear implantation (CIPRES): a study protocol for a randomized single-blind controlled trial

Abstract

Background In order to preserve residual hearing in patients with sensorineural hearing loss (SNHL) who receive a cochlear implant (CI), insertion trauma to the delicate structures of the cochlea needs to be minimized. The surgical approach comprises the conventional mastoidectomy-posterior tympanotomy (MPT) to arrive at the middle ear, followed by either a cochleostomy (CO) or the round window (RW) approach. Both techniques have their benefits and disadvantages. Another important aspect in structure preservation is the design of the electrode array. Two different designs are used: a “straight” lateral wall lying electrode array (LW) or a “pre-curved” perimodiolar lying electrode array (PM). Interestingly, until now, the best surgical approach and design of the implant is uncertain. Our hypothesis is that there is a difference in hearing preservation outcomes between the four possible treatment options. Methods We designed a monocenter, multi-arm, randomized controlled trial to compare insertion trauma between four groups of patients, with each group having a unique combination of an electrode array type (LW or PM) and surgical approach (RW or CO). In total, 48 patients will be randomized into one of these four intervention groups. Our primary objective is the comparison of postoperative hearing preservation between these four groups. Secondly, we aim to assess structure preservation (i.e., scalar translocation, with basilar membrane disruption or tip fold-over of array) for each group. Thirdly, we will compare objective outcomes of hearing and structure preservation by way of electrocochleography (ECochG). Discussion Cochlear implantation by way of a cochleostomy or round window approach, using different electrode array types, is the standard medical care for patients with severe to profound bilateral sensorineural hearing loss, as it is a relatively simple and low-risk procedure that greatly benefits patients. However, loss of residual hearing remains a problem. This trial is the first randomized controlled trial that evaluates the effect of cochlear insertion trauma of several CI treatment options on hearing preservation. Trial registration Netherlands Trial Register (NTR) NL8586. Registered on 4 May 2020. Retrospectively registered; 3/48 participants were included before registration.

Cochlear implantation impairs intracochlear microcirculation and counteracts iNOS induction in guinea pigs

“…Hearing loss causes following cochlear implantation can be divided into immediate and delayed types. Immediate hearing loss occurs directly after electrode array insertion and is likely caused by mechanical forces potentially leading to scalar translocation ( Shaul et al, 2018 ; Jwair et al, 2021 ). Consistent with findings by Jia et al, disturbances in blood flow following CI electrode array insertion were observed ( Jia et al, 2013 ).…”

Orientation of the Cochlea From a Surgeon’s Perspective

“…Thus, there is a lack of awareness in the coiling planes and the importance of aligning the planes. This fact may become an issue when the outcomes of straight and perimodiolar electrode arrays are statistically compared ( 12 ), as surgeons who do not take care to align the coiling planes may cause unfavorable outcomes more often in cases with perimodiolar electrode arrays than in those cases who chose straight electrode arrays. For example, the evaluation of hearing preservation outcomes in slim perimodiolar electrode arrays vary widely, with some studies with smaller group of surgeons finding such devices to be feasible ( 13 , 14 ), while a meta-analysis involving a wider range of surgeons in 33 studies recommend against the use of perimodiolar arrays ( 15 ).…”

Current Concepts and Future Trends in Increasing the Benefits of Cochlear Implantation: A Narrative Review

“…The procedure is more likely associated with perilymph loss, acoustic trauma, bone dust-related inflammatory reaction followed by osteoneogenesis, or spiral lamina damage than in the case of round window insertion [23]. Conflicting results regarding residual hearing preservation with each approach concede no clear benefit of a particular surgical approach for cochlear implantation [15,25,26]. An ongoing clinical randomized controlled trial (CIPRES) is being conducted with the aim of clarifying this aspect by comparing hearing preservation following cochlear implantation, considering four frequent combinations of surgical approaches (round window and cochleostomy) and electrode array designs (straight and pre-curved) [27].…”