Atraumatic Scala Tympani Cochleostomy; Resolution of the Dilemma

The Laryngoscope, 2007

Objective: To assess intracochlear trauma using two different round window-related cochleostomy techniques in human temporal bones. Methods: Twenty-eight human temporal bones were included in this study. In 21 specimens, cochleostomies were initiated inferior to the round window (RW) annulus. In seven bones, cochleostomies were drilled anterior-inferior to the RW annulus. Limited cochlear implant electrode insertions were performed in 19 bones. In each specimen, promontory anatomy and cochleostomy drilling were photographically documented. Basal cochlear damage was assessed histologically and electrode insertion properties were documented in implanted bones. Results: All implanted specimens showed clear scala tympani electrode placements regardless of cochleostomy technique. All 21 inferior cochleostomies were atraumatic. Anterior-inferior cochleostomies resulted in various degrees of intracochlear trauma in all seven bones. Conclusion: For atraumatic opening of the scala tympani using a cochleostomy approach, initiation of drilling should proceed from inferior to the round window annulus, with gradual progression toward the undersurface of the lumen. While cochleostomies initiated anterior-inferior to the round window annulus resulted in scala tympani opening, many of these bones displayed varying degrees of intracochlear trauma that may result in hearing loss. When intracochlear drilling is avoided, the anterior bony margin of the cochleostomy remains a significant intracochlear impediment to in-line electrode insertion.

Acta Oto-Laryngologica, 2009

2009

Our study was designed to compare two surgical approaches that are currently employed in cochlear implantation.

European Archives of Oto-Rhino-Laryngology, 2009

A surgical approach using the external auditory canal and the round window as a natural access pathway for cochlear implant positioning, the endomeatal approach, is described. This approach avoids performing an antromastoidectomy, the subsequent posterior tympanotomy and the promontorial cochleostomy. The endomeatal approach also allows an optimal insertion plane for electrode array atraumatic insertion through the round window.The technique was developed and practiced in 35 fresh temporal bones and then it was applied in ten patients. This surgery has an endomeatal Wrst stage, which begins with a stapedectomylike tympanomeatal Xap. This Xap allows an easy access to scala tympani via round window niche. The internal part of a groove is drilled on the posterior wall of the EAC. The groove is parallel to the EAC axis and starts in its inner border. Once the endomeatal stage is completed, a standard retroauricular approach is performed, in order to make the receptor-stimulator well and to complete the groove externally, until it connects the middle ear with the external mastoid surface. A Xat second well is drilled in front of the Wrst one to lodge the remaining electrode lead. In small children this well is deepened. The electrode array is introduced in the scala tympani through the RW and located into the groove. The electrode is covered and Wxed inside the groove with bone paté. The extra length of the electrode lead is located in the second well and the receptor-stimulator is Wxed in its well. The ground electrode is placed under the periosteum, the retroauricular incision is sutured, the tympanomeatal Xap is restored and a dressing is placed into the EAC. Surgical time was signiWcantly shorter than in standard approach. There were neither surgical nor healing complications. Electrode insertion was easy and complete and functional results were adequate. The goal of this approach is to avoid antromastoidectomy and posterior tympanotomy, which are replaced by the EAC groove. It is faster and safer, eliminating the risk of facial nerve injury. It also allows a better access to the round window, with a less traumatic electrode insertion, suitable for "soft surgery" performing. It may advantageously replace the classical transmastoideal approach.

The Egyptian Journal of Otolaryngology, 2014

Acta Medica Marisiensis, 2015

We aimed to underline the surgical importance of the distances between the landmarks of the temporal bone, important for quantifying the benefits and disadvantages of two different cochlear implant techniques. Methods: We have gathered all data from the Radiology Department in Emergency County Hospital in Tîrgu Mureș, namely computed tomography imagistic studies in order to perform the required measurements, according to pre-defined inclusion/exclusion criteria. The time interval was 5 months. Results: The comparison between the sets of data shows a good match for the risk/benefit ratio for the two types of technique for cochlear implantation. Conclusions: The middle cerebral fossa approach for the electrode insertion into the cochlea is a viable and needed surgical technique as the classic approach has reached its boundaries and new challenges appear. As surgical decisions are largely based on radiology data, our work underlines the importance of solving the borderline pathology, the extreme cases and the role of surgery in improving the quality of life for every patient with cochlear implant indication.

Annals of Otology and Neurotology, 2018

Introduction Different surgical approaches have been adopted for cochlear implantation, with cortical mastoidectomy-posterior tympanotomy being the most commonly followed technique. Method In this article, we describe the surgical technique for cochlear implant followed at our center, which has been successfully implemented in more than 2,500 cochlear implant surgeries. Cochlear implant surgery using the cortical mastoidectomyposterior tympanotomy technique has been performed in more than 2,500 cases with some modifications to the original technique over a period of time. Results In spite of not using tie-down holes and securing down the receiver-stimulator with sutures, no cases of receiver-stimulator displacement or outward electrode migration have been noted with the current technique of creating a snug-fitting subperiosteal pocket along with a hook for the electrode array. Conclusion Adhering to a strict intraoperative surgical protocol plays an extremely important role in carrying out successful cochlear implant surgeries with minimal complications.

Zagazig University Medical Journal, 2014

Background: Cochlear implant is established as an effective and safe method of rehabilitation for profoundly deaf patients. There are two common surgical approaches for cochlear implantation. The first surgical approach, with mastoidectomy and posterior tympanotomy, is known as the classic approach or posterior tympanotomy approach. The second surgical approach, without mastoidectomy or posterior tympanotomy, is known as the suprameatal approach. Using the suprameatal approach, the active electrode is inserted and posterior tympanotomy. Aim of the work: To compare between suprameatal approach and posterior tympanotomy approach in cochlear implantation. Patients and methods: This study was conducted on 30 patients that underwent cochlear implantation surgery in Zagazig University Hospital, in the period from October 2010 to April 2014. The patients were 19 males and 11 females, their age ranged from 2 to 7 years. Patients were divided to 2 groups: one group was implanted by the supra meatal approach (6 patients) and the other one was implanted by posterior tympanotomy approach (24 patients). Results: There was a significant difference between the 2 groups as regard the total duration of surgery in favor of 1 st group A (SMA). There was no significant difference between the 2 groups as regard the total number of major or minor complications. But there was one case of facial nerve paralysis in a child implanted by the classic approach. Conclusion: SMA may be clearly a good alternative to the classical surgery technique for CI in terms of reducing the duration of surgery and reducing the incidence of facial and chorda tympani nerve injury.

Otology & Neurotology, 2012

Hypothesis-Cochleostomy or round window enlargement techniques for cochlear implant electrode insertion result in more abnormal tissue formation in the basal cochlea and are more apt to produce endolymphatic hydrops than round window electrode insertion. Methods-Twelve temporal bones from implanted patients were examined under light microscopy and reconstructed with 3D reconstruction software to determine cochlear damage and volume of neo-ossification and fibrosis following electrode insertion. Amount of new tissue was compared between three groups of bones: insertion through the round window (RW), after enlarging the round window (RWE) and cochleostomy (Cochl). The probable role of the electrode was evaluated in each case with hydrops. Results-More initial damage occurred in the Cochl and RWE groups than in the RW group, and the difference was significant between RWE and RW in cochlear segment I (p<0.026). The volume of new bone in segment I differed significantly between groups (p<.012) and was greater in the RWE group than in either the Cochl or RW groups (post hoc p's <.035 and .019). Hydrops was seen in 5 cases, all in the Cochl and RWE groups. Blockage of the duct was due to new tissue formation in 4 of the 5 hydrops cases. Conclusion-With the electrodes in this serie, implantation through the round window minimized initial intracochlear trauma and subsequent new tissue formation, while the round window extension technique used at the time of these implantations produced the greatest damage. Future studies may clarify whether today's techniques and electrodes will produce these same patterns of damage.

Acta Oto-Laryngologica, 2006

Conclusions. Except for basal cochlear traumatization, all specimens implanted into scala tympani showed atraumatic insertion properties and good perimodiolar electrode positioning. Cochleostomy preparation and placement can have a significant impact on levels of basal cochlear trauma. Objective. In the past, perimodiolar cochlear implant electrodes increased the risk for intracochlear traumatization when compared to free-fitting arrays. Recently, however, clinical evidence for atraumatic perimodiolar implantations with preservation of residual hearing has been described. The aim of this paper was to histologically evaluate a perimodiolar cochlear implant array for its insertion properties in cadaver human temporal bones. Surgical and electrode factors, as well as preparation artifacts influencing intracochlear trauma, were considered in the evaluation. Materials and methods. Sixteen human temporal bones were harvested up to 24 hours post mortem and implanted immediately with the Nucleus 24 Contour Advance cochlear implant electrode array. Implantations were either performed using a regular caudal approach cochleostomy or through the round window membrane. After implantation, all bones underwent special histological processing, which allowed sectioning of undecalcified bone. Insertion properties were evaluated according to a grading system. Results. Fourteen specimens were implanted into scala tympani and only two exhibited basal trauma attributable to electrode insertion characteristics. Two bones were implanted into scala vestibuli after causing trauma in the region of the cochleostomy. Insertion depths ranged from 1808 to 4008. All bones showed good perimodiolar electrode positioning. Basal trauma due to surgical issues and histological artifacts was present in 10 of 16 bones.