Narrow Facial Recess Research Articles

Otopathologic Abnormalities in CHARGE Syndrome.

To perform an otopathologic analysis of temporal bones (TBs) with CHARGE syndrome. Otopathologic study of human TB specimens. Otopathology laboratories. From the otopathology laboratories at the University of Minnesota and Massachusetts Eye and Ear Infirmary, we selected TBs from donors with CHARGE syndrome. These TBs were serially sectioned at a thickness of 20 µm, and every 10th section was stained with hematoxylin and eosin. We performed otopathologic analyses of the external ear, middle ear (middle ear cleft, mucosal lining, ossicles, mastoid, and facial nerve), and inner ear (cochlea, vestibule, internal auditory canal, and cochlear and vestibular nerves). The gathered data were statistically analyzed. Our study included 12 TBs from 6 donors. We found a high prevalence of abnormalities affecting the ears. The most frequent findings were stapes malformation (100%), aberrant course of the facial nerve (100%) with narrow facial recess (50%), sclerotic and hypodeveloped mastoids (50%), cochlear (100%) and vestibular (83.3%) hypoplasia with aplasia of the semicircular canals, hypoplasia and aplasia of the cochlear (66.6%) and vestibular (91.6%) nerves, and narrowing of the bony canal of the cochlear nerve (66.6%). The number of spiral ganglion and Scarpa's ganglion neurons were decreased in all specimens (versus normative data). In our study, CHARGE syndrome was associated with multiple TB abnormalities that may severely affect audiovestibular function and rehabilitation.

Active and Adequate Exposure of the Facial Nerve and Chorda Tympani Nerve to Improve the Safety of Cochlear Implantation.

The posterior tympanum approach of cochlear implantation is easy to damage the facial nerve and cord tympanic nerve. Therefore, we need to improve the safety of cochlear implantation. To discuss the safety and feasibility of active and adequate transparent exposure of the facial nerve and chorda tympani nerve during the surgery. A retrospective analysis was performed on all 945 patients who underwent cochlear implantation from January 2011 to September 2017. All patients have been followed up for 14 months to 5 years postoperatively and postoperative complications have been observed. All 945 patients received artificial cochlear implantation. The facial nerves of 76 cases were above the horizontal semicircular canal plane, while narrow facial recess was observed in 44 cases. Serious chorda tympani nerve variation was found in 1 case. No facial paralysis and facial nerve irritation and abnormal taste occurred after operation. Cochlear implantation with initiative and adequate exposure of facial nerve and the chorda tympani nerve can improve the safety of the cochlear implant surgery. Our study provide a safe and effective method for clinical cochlear implantation to reduce facial nerve and tympanic cord nerve injury.

Evaluation of facial nerve course, posterior tympanotomy width and visibility of round window in patients with cochlear implantation by performing oblique sagittal cut computed tomographic scan temporal bone

Abstract Posterior tympanotomy is a well-known otologic procedure that allows surgeons access to the middle ear cavity. During posterior tympanotomy the surgeon can approach the round window niche and promontory, where a cochleostomy is carried out for cochlear implant electrode array insertion. The mastoid segment of the facial nerve and the chorda tympani nerve could be injured in cases of narrow facial recess or inadequate posterior tympanotomy. With the image reconstruction in an oblique sagittal plane and curve reconstructions, the whole tympanic and mastoid segments of the facial nerve can be visualized in just one image. It is necessary to preoperatively estimate both the facial nerve status and the anatomical relationships between the facial recess and the round window, this may reduce the risk of facial nerve injury and influence the decision on which side to implant, which approach to use and whether to enter the cochlea via cochleostomy or round window membrane route. The aim of our study is to evaluate the facial nerve (course and anomalies), visibility of the round window membrane and the width of posterior tympanotomy before cochlear implantation by using oblique sagittal cuts CT scan temporal bone. A prospective study; done on 18 consecutive patients with severe to profound sensorineural hearing loss who are candidates for cochlear implantation in Ain Shams University Hospitals during years 2011 & 2012. We focused on oblique sagittal cut CT scan & its role to evaluate the course of facial nerve, posterior tympanotomy width and visibility of the round window. We tried to make a statistical correlation between CT scan and intraoperative findings. Statistically significant positive correlation between posterior tympanotomy width and 2nd genu angle, distance from facial bony canal to round window and distance from facial nerve to round window. The mean distance from facial bony canal to round window was longer in operatively viewed round window than non-viewed window (4.7 and 4.4 mm respectively) (P < 0.05). The mean distance from facial nerve to round window was longer in operatively viewed round window membrane than non-viewed window (5.9 and 5.5 mm respectively) (P < 0.05). The mean width of posterior tympanotomy was wider in operatively viewed round window niche than non-viewed window niche (3.1 and 3.0 mm respectively) (P < 0.01). Oblique sagittal cuts CT scan temporal bone is very helpful preoperative radiological tool for evaluation of the facial nerve course and anatomical factors that may determine the field of view or the accessibility of the posterior tympanotomy for either cochleostomy or round window membrane approach. Other approaches can be used with more safety when the position of the facial nerve prevents an adequate posterior tympanotomy.

In Vitro Accuracy Evaluation of Image-Guided Robot System for Direct Cochlear Access

A previously developed image-guided robot system can safely drill a tunnel from the lateral mastoid surface, through the facial recess, to the middle ear, as a viable alternative to conventional mastoidectomy for cochlear electrode insertion. Direct cochlear access (DCA) provides a minimally invasive tunnel from the lateral surface of the mastoid through the facial recess to the middle ear for cochlear electrode insertion. A safe and effective tunnel drilled through the narrow facial recess requires a highly accurate image-guided surgical system. Previous attempts have relied on patient-specific templates and robotic systems to guide drilling tools. In this study, we report on improvements made to an image-guided surgical robot system developed specifically for this purpose and the resulting accuracy achieved in vitro. The proposed image-guided robotic DCA procedure was carried out bilaterally on 4 whole head cadaver specimens. Specimens were implanted with titanium fiducial markers and imaged with cone-beam CT. A preoperative plan was created using a custom software package wherein relevant anatomical structures of the facial recess were segmented, and a drill trajectory targeting the round window was defined. Patient-to-image registration was performed with the custom robot system to reference the preoperative plan, and the DCA tunnel was drilled in 3 stages with progressively longer drill bits. The position of the drilled tunnel was defined as a line fitted to a point cloud of the segmented tunnel using principle component analysis (PCA function in MatLab). The accuracy of the DCA was then assessed by coregistering preoperative and postoperative image data and measuring the deviation of the drilled tunnel from the plan. The final step of electrode insertion was also performed through the DCA tunnel after manual removal of the promontory through the external auditory canal. Drilling error was defined as the lateral deviation of the tool in the plane perpendicular to the drill axis (excluding depth error). Errors of 0.08 ± 0.05 mm and 0.15 ± 0.08 mm were measured on the lateral mastoid surface and at the target on the round window, respectively (n =8). Full electrode insertion was possible for 7 cases. In 1 case, the electrode was partially inserted with 1 contact pair external to the cochlea. The purpose-built robot system was able to perform a safe and reliable DCA for cochlear implantation. The workflow implemented in this study mimics the envisioned clinical procedure showing the feasibility of future clinical implementation.

Cochlear implantation surgery in patients with narrow facial recess

Conclusion: The new method of facial recess enlargement through suspending, antedisplacing, and adhering the chorda tympani nerve to the posterior wall of the auditory canal can expose the round window, make electrode insertion easier, and preserve the function of the facial nerve and chorda tympani nerve. Objective: To describe and report cochlear implantation surgery in patients with narrow facial recess, including surgical technique and postoperative outcomes. Methods: Cochlear implantation surgery was performed in our hospital in 39 cases with narrow facial recess by enlarging the facial recess. To enlarge the distance between the facial nerve and chorda tympani nerve, the chorda tympani nerve was suspended. The chorda tympani was anteplaced and adhered to the posterior wall of the auditory canal. Results: Among the 39 cases, the narrowest distance between the facial nerve and the chorda tympani nerve was less than 1.0 mm. All patients successfully underwent cochlear implantation surgery. No injuries of the facial nerve, chorda tympani nerve, or the posterior wall of the auditory canal were reported in any of the patients. There were significant differences in the injuries of the facial nerve, chorda tympani nerve, and posterior wall of the auditory canal in these cases compared with previous approaches to this operation.

Safety and patient selection of totally implantable hearing aid surgery: Envoy system, Esteem

Patient's low compliance of conventional hearing aids has lead to innovation of totally implantable hearing devices such as Esteem, Envoy system. This study was designed to evaluate safety of device implantation, patient's hearing gain, importance of anatomic landmarks, and to describe suitable criteria for patient selection. Via a non-randomized controlled clinical trial, ten patients with moderate-to-severe sensorineural hearing loss were implanted from 2007 to 2009. Mean follow-up period was 29.4months. Correlation of pre-operative temporal bone CT scan anatomy with postoperative outcome was evaluated. Except one, all other implanted devices are active and patients' overall average hearing gain are similar to conventional hearing aids (10-22dB), but patients reported relatively better subjective sound quality compared with their pre-operative conventional hearing aids. One implanted device was explanted in a patient due to facial weakness and low-hearing gain. Revision surgery was done successfully in another patient secondary to excessive bone growth. Totally implantable hearing device surgery seems to be relatively safe and correct patient selection could lead to good outcomes. Lateral location of facial nerve, sclerotic mastoid air cells and narrow facial recess space seems to be related to postoperative complications.

A True Minimally Invasive Approach for Cochlear Implantation

High-precision intraoperative navigation using high-resolution flat-panel volume computed tomography makes feasible the possibility of minimally invasive cochlear implant surgery, including cochleostomy. Conventional cochlear implant surgery is typically performed via mastoidectomy with facial recess to identify and avoid damage to vital anatomic landmarks. To accomplish this procedure via a minimally invasive approach--without performing mastoidectomy--in a precise fashion, image-guided technology is necessary. With such an approach, surgical time and expertise may be reduced, and hearing preservation may be improved. Flat-panel volume computed tomography was used to scan 4 human temporal bones. A drilling channel was planned preoperatively from the mastoid surface to the round window niche, providing a margin of safety to all functional important structures (e.g., facial nerve, chorda tympani, incus). Postoperatively, computed tomographic imaging and conventional surgical exploration of the drilled route to the cochlea were performed. All 4 specimens showed a cochleostomy located at the scala tympani anterior inferior to the round window. The chorda tympani was damaged in 1 specimen--this was preoperatively planned as a narrow facial recess was encountered. Using flat-panel volume computed tomography for image-guided surgical navigation, we were able to perform minimally invasive cochlear implant surgery defined as a narrow, single-channel mastoidotomy with cochleostomy. Although this finding is preliminary, it is technologically achievable.

Suprameatal approach for cochlear implantation in 45 Chinese children

To investigate the feasibility of applying the suprameatal approach (SMA) for cochlear implantation in Chinese children with profound sensory hearing loss, and to demonstrate a technical modification incorporated in the procedure due to an observed racial difference. Retrospective study. University hospital. Forty-five Chinese children (total 47 ears) with profound sensory hearing loss were surgically treated from May 2005 to May 2006. The patients were followed anywhere from 1 month to 20 months post-surgery, with 30 patients being followed for more than 6 months. All patients received cochlear implantation through the suprameatal approach. In this procedure, the cochleostomy was performed in one stage after the suprameatal tunnel was finished, rather than the two-stage approach described by Kronenberg (who firstly introduced the suprameatal approach). Three patients with low-lying dura (which is considered to be the contraindication for cochlear implantation with SMA) were treated with a further modified surgical approach. Among the 47 ears, full electrode pairs were completely inserted in 45 ears without surgical difficulties, but 1 ear was only fitted with 9 pairs of electrodes because of an ossified cochlea, and another with just 8 pairs of electrodes due to serious cochlear dysplasia. An intraoperative "gusher" occurred in the dysplasia case, and a small piece of temporalis muscle was used, along with biology glue, to seal the cochleostomy and prevent further leakage. In 1 case, the electrode was inserted into the cochlea through the tunnel lateral to the chorda tympani because adhesion had occurred between the incus and chorda tympani. There were no postoperative complications in any case. Thirty cases exhibited better hearing or speech development from cochlear implantation after more than 6 months of follow-up. The SMA was found to be a simple and safe technique for cochlear implantation in Chinese children. It enables wide exposure of the middle ear, and is especially suitable for cases with a narrow facial recess, an anteriorly located facial nerve, or an ossified cochlea. It is almost impossible to injure the facial nerve or the chorda tympani nerve. The cochleostomy can be performed in one stage in those patients with a normal cochlea. With some modifications, a low-lying dura will not be the absolute contraindication of SMA.

Navigationsgeführte minimal-invasive Cochlea-Implantation - Untersuchungen am humanen Felsenbein

The accuracy of navigation systems can be improved significantly by using high-resolution flat panel-based Volume Computed Tomography (fpVCT) so that new surgical therapeutic concepts become feasible. A navigation-guided minimally-invasive cochleostomy places highest requirements on the accuracy of intraoperative navigation. A flat-panel Volume Computed Tomograph (fpVCT) was used to scan four human temporal bones. The isometric voxel size was 200 microm. The preoperative planning was used to define an optimized drilling channel from the mastoid surface to the round window niche and the scala tympani providing a safety margin to critical anatomical structures such as facial nerve, chorda tympani, sigmoid sinus and posterior wall of auditory canal. The canal was drilled hand-operated with a navigated drill following the previously planned trajectory. Afterwards the drilled canal was imaged by fpVCT. Conventional dissection including mastoidectomy and posterior tympanotomy assured correct localization of the cochleostomy. Path planning took an average of 54 minutes (range 35-85 minutes). Installation took an average of 16 minutes (range 14-19 minutes). The drilling procedure itself took an average of 7.75 min (range 5-12 minutes.) The RMSE-values varied between 0.1 and 0.2 mm (Table 1). All four specimens showed a cochleostomy located at the scala tympani anterior inferior to the round window. The chorda tympani was damaged in one specimen--this was preoperatively planned as a narrow facial recess was encountered. The time needed for planning and system-installation could be reduced continuously. This feasibility study demonstrates that using current image-guided surgery technology in combination with fpVCT allows drilling of a minimally invasive channel to the cochlea with loco typico cochleostomy. The necessary accuracy of intraoperative navigation can be achieved by use of fpVCT (technical accuracy between 0.1 and 0.2 mm). Our results demonstrate the feasibility of a navigation-guided minimally-invasive cochleostomy loco typico. While we are enthused by this preliminary work, we recognize the barriers which exist in translation to clinical application. These include surgical issues (e.g. control of unexpected bleeding) and electrode issues (e.g. development of insertion tools).

Suprameatal approach for cochlear implantation: Experience with 180 patients

Objectives: To review our experience with the suprameatal approach (SMA) as an alternative method for cochlear implantation (CI). This technique eliminates the need for mastoidectomy and posterior tympanotomy in CI and is based on the retroauricular tympanotomy approach for middle ear surgery. Methods: Retrospective case review. One hundred eighty patients were operated on using the SMA. The middle ear cavity was entered through a retroauricular tympanotomy flap and the electrode was inserted into the cochlea via a tunnel drilled in the suprameatal region superior to Henle’s spine at about 1 o’clock position to the external auditory canal. Results: There were no postoperative complications and no signifficant differences in the speech perception obtained in the patients implanted using SMA as compared to the classic technique. Conclusions: SMA was found to be a simple and safe technique that does not endanger the facial nerve or the chorda tympani nerve. It enables wide exposure of middle ear and is especially suitable for malformed cochleae, narrow facial recess, or anteriorly located facial nerve. Exclusion of mastoidectomy minimizes the amount of drilling and shortens duration of surgery.