Evaluation of a Less Invasive Cochlear Implant Surgery in OPA1 Mutations Provoking Deafblindness.

Cochlear implantation (CI) for deafblindness may have more impact than for non-syndromic hearing loss. Deafblind patients have a double handicap in a society that is more and more empowered by fast communication. CI is a remedy for deafness, but requires revision surgery every 20 to 25 years, and thus placement should be minimally invasive. Furthermore, failed reimplantation surgery will have more impact on a deafblind person. In this context, we assessed the safety of minimally invasive robotically assisted cochlear implant surgery (RACIS) for the first time in a deafblind patient. Standard pure tone audiometry and speech audiometry were performed in a patient with deafblindness as part of this robotic-assisted CI study before and after surgery. This patient, with an optic atrophy 1 (OPA1) (OMIM#165500) mutation consented to RACIS for the second (contralateral) CI. The applicability and safety of RACIS were evaluated as well as her subjective opinion on her disability. RACIS was uneventful with successful surgical and auditory outcomes in this case of deafblindness due to the OPA1 mutation. RACIS appears to be a safe and beneficial intervention to increase communication skills in the cases of deafblindness due to an OPA1 mutation. The use of RACIS use should be widespread in deafblindness as it minimizes surgical trauma and possible failures.

A New Pathogenic Variant in POU3F4 Causing Deafness Due to an Incomplete Partition of the Cochlea Paved the Way for Innovative Surgery.

Incomplete partition type III (IP-III) is a relatively rare inner ear malformation that has been associated with a POU3F4 gene mutation. The IP-III anomaly is mainly characterized by incomplete separation of the modiolus of the cochlea from the internal auditory canal. We describe a 71-year-old woman with profound sensorineural hearing loss diagnosed with an IP-III of the cochlea that underwent cochlear implantation. Via targeted sequencing with a non-syndromic gene panel, we identified a heterozygous c.934G > C p. (Ala31Pro) pathogenic variant in the POU3F4 gene that has not been reported previously. IP-III of the cochlea is challenging for cochlear implant surgery for two main reasons: liquor cerebrospinalis gusher and electrode misplacement. Surgically, it may be better to opt for a shorter array because it is less likely for misplacement with the electrode in a false route. Secondly, the surgeon has to consider the insertion angles of cochlear access very strictly to avoid misplacement along the inner ear canal. Genetic results in well describes genotype-phenotype correlations are a strong clinical tool and as in this case guided surgical planning and robotic execution.

Comparison of the Surgical Techniques and Robotic Techniques for Cochlear Implantation in Terms of the Trajectories Toward the Inner Ear.

OBJECTIVES: The ideal outcome of cochlear implant surgery involves the insertion of the array inside the scala tympani of the cochlea with the least mechanical trauma. Recently, round window insertion and the direction in which the cochlea is approached have gained attention in this respect. The Angles of Cochlear Approach (ACA) can be defined with a plane in the plane of the basal turn, termed the in-plane angle, and the plane orthogonal to this plane, termed the out-plane angle. The aim of this study was to compare the trajectory angles for different surgical techniques of Veria, suprameatal, pericanal, and multiple posterior tympanotomy (PT) approaches, including an optimal trajectory that is simulated for robotic surgery. MATERIALS AND METHODS: The trajectories of these surgical techniques were simulated on the same high-resolution computed tomography scan. The simulated trajectory angles were analyzed with dedicated software for medical images, defining the ACA and distances to critical otological structures. RESULTS: The ACA are the smallest for surgical techniques that pass thought the PT. However, performing a surgical PT can include variability in the ACA, ranging from almost 0° to 20.8° in an out-plane angle, depending on how close a surgeon would approach the facial nerve. The Veria, Suprameatal approach (SMA), and peri-canal approaches have larger ACA and minimal distances to the ossicular chain and the ear canal. The maximum distance to the facial nerve and the widest out-plane angle is observe with a pericanal approach. The optimal PT approach refers to the trajectory without collisions and with the best possible ACA that can be planned. CONCLUSION: Different surgical approaches yield important differences in the ACA. PT allows better ACA with maximum distances to the critical structures. However, the optimal PT trajectory simulated for robotic keyhole surgery is a further improvement on the trajectories through the facial recess.

Fundus obliteration and facial nerve outcome in vestibular schwannoma surgery.

The major objectives in vestibular schwannoma (VS) surgery have evolved from reducing mortality to functional preservation of the facial nerve and hearing. Absence of fluid between the lateral end of the VS and the internal auditory canal fundus on magnetic resonance imaging (MRI) appeared to have a negative influence on hearing outcome. Our goal was to study the prognostic significance of fundus obliteration on facial nerve function after VS surgery in patients with clinically normal facial function. We performed a retrospective review in a tertiary referral neurotology unit or 110 consecutive patients with a surgically removed VS and normal preoperative facial nerve function. Facial nerve function was evaluated at 1 month and 1 year by using the House-Brackmann (HB) scale and correlated to fundus obliteration on MRI. Facial nerve function was intact preoperatively in 114 of 123 patients (92.7%). We noticed a statistically significant difference and worse short-term outcome when the fundus was obliterated: 29.7% had HB 3 or more versus 13.0% if no fundus obliteration was seen. This statistically significant difference disappeared at 1 year. Fundus obliteration has a negative prognostic influence on short-term facial nerve function after VS surgery in patients with clinically normal facial function preoperatively.