Comparison of two cochlear implantation techniques and their effects on the preservation of residual hearing. Is the surgical approach of any importance?

The goal of this work was to review the pre-and postsurgical auditory thresholds of two surgical implantation techniques, namely the mastoidectomy with posterior tympanotomy approach (MPTA) and suprameatal approach (SMA), to determine whether there is a difference in the degree of preservation of residual hearing. In a series of 430 consecutive implanted patients 227 patients had measurable pre-operative hearing thresholds at 250, 500, and 1,000 Hz. These patients were divided into two groups according to the surgical technique that was used for implantation. The SMA approach was followed for 84 patients in Amsterdam, whereas the MPTA technique was adhered to 143 patients in Maastricht. The outcome variables of interest were alteration of pre-and postoperative auditory thresholds after cochlear implantation. Complete or partial preservation of residual hearing was obtained in 21.4 and 21.7% in the SMA and MPTA group, respectively. No statistical differences could be found between the SMA and MPTA group (p = 0.96; Chi-square test). The SMA technique is correlated with a similar degree of hearing loss after cochlear implantation compared to the MPTA technique. However, both techniques were not able to conserve a measurable amount of hearing in patients with a substantial degree of residual hearing. Therefore, both surgical techniques need to be refined for patients in which residual acoustical hearing is pursued.

Post-operative complications of cochlear implantation in adults and children: five years' experience in Maastricht.

Although cochlear implantation is considered a safe method of rehabilitation for profoundly deaf individuals, a number of these patients suffer complications after surgery. To evaluate post-operative complications after cochlear implantation, a retrospective chart review was performed for 112 patients who had undergone implantation in the Maastricht Academic Hospital. Minor complications were defined as those that could be overcome by medical or audiological management. These occurred in 36 patients (32 per cent) and all were managed successfully. Major complications were defined as device extrusion and those requiring further surgery, and these were identified in four patients (3.6 per cent). These complications included wound infection and device failure mediated by middle-ear pathology. In cases of chronic otitis media, we recommend performance of cochlear implantation as a staged procedure. In order to reduce the post-operative incidence of acute otitis media, we recommend adenoidectomy, placement of ventilation tubes and early antibiotic treatment.

Cochlear implantation in a patient with deafness induced by Charcot-Marie-Tooth disease (hereditary motor and sensory neuropathies).

Charcot-Marie-Tooth disease (CMT), also named hereditary motor and sensory neuropathies (HMSN), comprises a clinically and genetically heterogeneous group of disorders affecting the peripheral nervous system. Deafness induced by CMT is clinically distinct among the genetically heterogeneous group of CMT disorders. Deafness in CMT patients is associated with point mutations or deletions in the transmembrane domain in the peripheral myelin gene (PMP) 22, which are in close proximity to the extracellular component of this gene. We present a patient with deafness induced by CMT type 1A, undergoing cochlear implantation. Prior investigations showed good results due to replacing a synchronous impulse by means of cochlear implantation in patients with auditory neuropathy.