The feasibility of endoscopic transcanal approach for insertion of various cochlear electrodes: a pilot study

Various approaches to the round window for cochlear implantation: a systematic review

OBJECTIVE

Round window approaches are used to insert a cochlear implant electrode array into the scala tympani. This study aimed to review the literature to find the reported round window approaches.

METHOD

This review was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses ('PRISMA') guidelines. Articles that described their surgical approach to the round window were included. The PubMed, Scopus, Web of Science and Cochrane Library electronic databases were searched through to June 2021. The study protocol was registered on Prospero (reference number: CRD42021226940).

RESULTS

A total of 42 reports were included. The following approaches were documented: the standard facial recess, keyhole, retrofacial, modified suprameatal, transaditus, combined posterior tympanotomy and endomeatal, modified Veria, canal wall down approaches, and endoscopically assisted technique.

CONCLUSION

This review suggested that there are numerous distinct round window approaches, providing alternatives when the round window is inaccessible through the standard facial recess.

The role of the endoscope in cochlear implantation. A systematic review

OBJECTIVE

To review the role of the endoscope in cochlear implantation (CI).

METHODS

MEDLINE, ScienceDirect, Google Scholar and the Cochrane Library databases as well as other sources were searched by two independent reviewers. Studies including patients undergoing either exclusively endoscopic or endoscopic ally assisted CI were eligible for inclusion. Endoscopic CI approaches and postoperative complications were the primary outcomes. Secondary endpoints included the degree of round window (RW) microscopic visualization according to St Thomas' Hospital classification as well as type of cochleostomy for electrode insertion in the scala tympani (ST).

RESULTS

Fourteen studies met the inclusion criteria comprising 191 endoscopic or endoscopically assisted CI cases. The endoscope was used for better visualization of the RW across all included studies, facilitated the insertion of the electrode in the ST and spared a mastoidectomy in a number of cases. No facial nerve palsy was reported in any of the studies. The most common complication was external auditory canal/ tympanic membrane tear followed by chorda tympani injury.

CONCLUSION

The microscopic CI approach is still the gold standard. The endoscope facilitates the recognition of the RW area and leads to successful and safe implantation particularly in difficult anatomical scenarios, ear malformations and advanced otosclerosis. Endoscopically assisted CI procedures offer the opportunity to avoid a posterior tympanotomy and reduce the risk of facial nerve injury. To date, the lack of long term data does not permit the widespread adoption of completely endoscopic CI procedures without a mastoidectomy.

Combined Endoscopic/Microscopic Cochlear Implantation Through the Oval Window

Standard round window (RW) cochlear implantation is a well-described technique. Implantation might be difficult in patients with inner and middle ear anomalies, in some cases because of not achieving adequate exposure to the RW, with a related higher risk of complications such as facial nerve injury. It is proposed a combined microscopic/endoscopic oval window approach in a 63 year old man affected by bilateral Menière disease, with bilateral severe sensorineural hearing loss, speech discrimination score for bysillabic words under 40% and a hidden RW by anomalous facial nerve course. All electrodes entered the cochlear with good freefield thresholds and auditory ability results. A partial marginalis nerve palsy occurred at the second postoperative day and completely reversed at 2 months from surgery. Endoscopicassisted oval window cochlear implantation may be a safe alternative surgical technique in cases where surgeons are not able to access RW.

Endoscopic visualisation of the round window during cochlear implantation

Background

Endoscopes provide a magnified view of the middle ear and visualisation of hidden areas. Otoendoscopes facilitate excellent visualisation of the round window niche during cochlear implantation.

Objective

To compare microscopic and endoscopic visualisation of the round window membrane during cochlear implantation in 20 patients.

Methods

Twenty patients who underwent cochlear implantation were included in the study. After maximum exposure of the round window, the accessibility of the round window membrane was graded according to the St Thomas Hospital classification, first by microscope and then by endoscope.

Results

With the use of the endoscope, visualisation of the round window membrane improved in all the patients as compared to the microscope. The electrode array was inserted via a round window or extended round window approach in all but two cases; the latter cases required bony cochleostomy because of unfavourable anatomy.

Conclusion

The main benefit of endoscope-assisted cochlear implantation is improved visibility of the round window region.

Endoscopic approach to the round window through posterior tympanotomy for cochlear implantation in children: A study on feasibility

OBJECTIVE

To demonstrate the feasibility of rigid endoscopy through posterior tympanotomy, which provides both a view of the round window and direction of the scala tympani in children.

METHODS

After a standard mini-invasive surgical approach with postauricular access and transmastoid posterior tympanotomy of 2 mm, a 0°, 1.9 mm diameter and 11 cm long endoscope is positioned in proximity of the upper part of the posterior tympanotomy to obtain a panoramic view of the inferior part of the medial wall of the tympanic cavity. Surgical complications and changes in hearing threshold were analyzed.

RESULTS

Eight children were submitted to cochlear implantation with endoscopic assistance through posterior tympanotomy. Complete visualization of the round window niche was possible in every ear. No complications related to the procedure were observed. Preoperative threshold was preserved in 9 of 10 ears.

CONCLUSIONS

Direct endoscopic view through the posterior tympanotomy allows visualization of the entire round window niche as well as the angle of introduction of the multi-electrode array along the direction of the scala tympani.

[The modern state and prospects of development of endoscopic otosurgery]

In this review presents data on efficiency endoscopic operations at some ear diseases. Now endoscopic operations are widely applied at primary and residual (or recuring) middle ear cholesteatomas, tympanic membrane perforation, otosclerosis and cochlear implantation. Proceeding from resolving power of endoscopic technology, endoscopic operation can be applied as an independent method, or as an endoscopic assisted, to be combined with otomicrosurgery operation. Efficiency of endoscopic operation in many respects is defined by a possibility of panoramic visualization of anatomical structures of middle and inner ear, and also carrying out high-quality elimination of focus lesion from areas, being remote when performing otomicrosurgery operation.

Preoperative simulation unveiled undetected surgical difficulties in a case of cochlear implantation

We herein report a case in which extensive preparation changed a difficult-to-treat patient into an easy one. We performed a revision cochlear implantation on a patient whose first procedure had been aborted due to unidentified difficulties. During a series of thorough three-dimensional simulations, we found that the patient in question had a normal cochlea but the cochlea was placed in an unusual position and orientation. This condition is difficult to detect on standard preoperative radiographic images. Through this simulation, we were able to propose a surgical plan to avoid making the same mistakes as the first surgeon. We present this case not as a rare difficult case of an unfortunate patient but instead emphasise the importance of performing surgical simulation and looking for non-obvious difficulties. This case is an example of the success that can be achieved with such extensive preparation.

Endoscope-Assisted Cochlear Implantation

OBJECTIVES

Our aim was to present our endoscope-assisted cochlear implantation (CI) technique, in which the middle ear landmarks were identified through the facial recess exposure by using an endoscopic view without elevating the tympanic annulus. The secondary goal was to assess whether the situation of difficult surgical exposure could be predicted by evaluating preoperative axial computed tomography (CT) examinations.

METHODS

CT examinations and surgical outcomes of endoscope-assisted CI surgeries were analyzed.

RESULTS

A total of 179 CI operations performed in 27 adults (15.1%) and 152 children (84.9%) were retrospectively evaluated. It was found that in 14 cases (7.8%), endoscopic examination contributed substantially in identifying the round window (RW) membrane correctly. Endoscopic identification of the RW through the posterior tympanotomy enabled us to perform a straightforward surgery in all these cases, without the need for switching to a bony cochleostomy or alternative surgical techniques. The difficulty in the surgical exposure was predicted preoperatively by examining the axial CT scans in six of the 14 cases (42.8%) for which endoscopic assistance was necessary in order to identify the RW correctly.

CONCLUSION

The main benefit of endoscope-assisted CI is the improved visibility leading to a panoramic view of the RW region. The implementation of transfacial recess endoscopic examination into the conventional CI technique is helpful to avoid problems during surgical orientation. However, the difficulty in the surgical exposure of the RW cannot be reliably predicted by the subjective evaluation of preoperative CT scans and more studies are needed to obtain reliable criteria.

Extending otology services to rural settings: Value of endoscopic ear surgery

Introduction:

Few centers, mainly located in urban settings offer otological surgical services, yet majority of patients requiring these services are rural based and are generally unable to access these centers with resulting disease chronicity and complications. This paper aims to describe the access of otological surgical services by a rural population.

Methodology:

This is a retrospective study of patients who accessed otological services at three secondary health institutions and one tertiary referral institution. All patients requiring ear surgery over a 4-year period were studied. The initial 2 years without ear endoscopic surgery was compared with the 2 years when ear endoscopic surgery was introduced. Hospital records were studied and relevant data were extracted.

Results:

Six hundred and nine ears required surgery over 4 years. Age ranged from 3 to 62 years, with a ratio of 1.4 males: 1 female. During the initial 2 years, all patients were referred from the three secondary health institutions to the urban-based tertiary institution for microscopic ear surgery, 94% failed to proceed on the referral. In the second 2 years, 34% were considered suitable for endoscopic ear surgery, of which 78% accepted and had surgery within the locality. Of the 66% referred, only 5% proceeded on the referral.

Conclusion:

With operator training and investment in portable ear endoscopy set, bulk of ear surgery needing magnification can be treated in the rural setting. This represents a most feasible means of extending the service to the targeted population.

[The endoscopic anatomy of the middle ear (a dissection study)]

The objective of the present work was to study the specific endoscopic anatomical features of the middle ear using the dissected temporal bones with the intact tympanic membrane. The 18 cm long endoscopes 4 mm in diameter with a visual angle from 0 to 45 degrees in the combination with some other microinstruments, such as ear pincers, needles, curettes, elevators, and suction tubes, were used during the examination. It was shown that endomeato-transtympanic endosopy provides a panoramic view of almost all structures of the middle ear. After the resection of the posterior bone edge of 'annulus tympanicus', the use of the 45o endoscope ensured the panoramic view not only of certain structures of the middle ear (e.g. the tympanic chord, the stapedius muscle tendon, the entire pyramidal process) but also of the structures of the retrotympanic and anterior epitympanic spaces.

Endoscopic cochlear implantation: Call for caution

OBJECTIVES/HYPOTHESIS

To assess whether transcanal endoscopic access to the basal turn of the cochlea for cochlear implantation is appropriate.

STUDY DESIGN

Case series study.

METHODS

We reviewed 100 consecutive computed tomographic studies of the sinuses and temporal bone in our institution. We excluded studies that demonstrated evidence of congenital anomalies, chronic ear disease, or inadequate visualization of the cochlea. On axial sections, the angles of the basal turn of the cochlea and of the ear canal in reference to the sagittal plane were recorded as a function of age.

RESULTS

Eighty-four studies were included and 16 were excluded. There was significant variability in the relationship between the ear canal and the basal turn of the cochlea in reference to the sagittal plane. A clear majority of images demonstrated the basal turn of the cochlea to align with a more posterior angle than that of the ear canal.

CONCLUSION

The trajectory provided by posterior tympanotomy aligns more favorably with the basal turn of the cochlea than transcanal access. Endoscopic technique, primarily an ear canal intervention, may not be useful in cochlear implant surgery.

LEVEL OF EVIDENCE

4. Laryngoscope, 126:689-692, 2016.

Systematic review of outcomes following observational and operative endoscopic middle ear surgery

OBJECTIVES

Middle ear surgery increasingly employs endoscopes as an adjunct to or replacement for the operative microscope. We provide a systematic review of endoscope applications in middle ear surgery with an emphasis on outcomes, including the need for conversion to microscope, audiometric findings, length of follow-up, as well as disease-specific outcomes.

DATA SOURCES

PubMed, Embase, and Cochrane CENTRAL database.

METHODS

A literature review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis recommendations. Articles were categorized based on study design, indication, and use of an endoscope either as an adjunct to or as a replacement for a microscope. Qualitative and descriptive analyses of studies and outcomes data were performed.

RESULTS

One-hundred three articles met inclusion and exclusion criteria. Of the identified articles, 38 provided outcomes data. The majority of these studies were moderate quality, retrospective, case-series reports. The indications for use of the endoscope were broad, with the most common being resection of cholesteatoma. In cholesteatoma surgery, endoscope approaches routinely identified residual cholesteatoma in primary and second-look cases. Other outcomes, including robust audiometric data, operating room times, wound healing, and quality of life surveys were not well described.

CONCLUSIONS

Endoscopes have consistently been used as an adjunct to the microscope to improve visualization of the tympanic cavity. Recent reports utilize the endoscope exclusively during surgical dissection; however, data comparing patient outcomes following the use of an endoscope to a microscope are lacking. Areas in need of additional research are highlighted.

LEVEL OF EVIDENCE

NA