Surgical Trauma After Sequential Insertion of Intracochlear Catheters and Electrode Arrays (a Histologic Study) (original) (raw)
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BioMed Research International, 2015
Hypothesis. This study aimed to evaluate whether there is a difference in the degree of intracochlear trauma when the cochlear implant electrode arrays is inserted through different quadrants of the round window membrane.Background. The benefits of residual hearing preservation in cochlear implant recipients have promoted the development of atraumatic surgeries. Minimal trauma during electrode insertion is crucial for residual hearing preservation.Methods. In total, 25 fresh human temporal bones were subjected to mastoidectomy and posterior tympanotomy. The cochlear implant electrode array was inserted through the anterosuperior quadrant of the round window membrane in 50% of the bones and through the anteroinferior quadrant in the remaining 50%. The temporal bones were dehydrated, embedded in epoxy, serially polished, stained, viewed through a stereomicroscope, and photographed with the electrode arraysin situ. The resulting images were analyzed for signs of intracochlear trauma.Re...
Comparative Study of Cochlear Damage With Three Perimodiolar Electrode Designs
The Laryngoscope, 2003
Objective: To describe intracochlear insertion trauma caused by three perimodiolar cochlear implant electrodes. Study Design: Descriptive histological study of 15 human cadaver temporal bones. Methods: Fifteen cadaver temporal bones underwent surface preparation and were implanted with one of the following perimodiolar electrode arrays: Combi 40؉PM (MedEl Corporation), HiFocus II (Advanced Bionics Corporation), or Contour (Cochlear Corporation). A cryosectioning technique was used to study horizontal sections at 200-m intervals with the electrode in place. Image-enhanced videofluoroscopy and computer-assisted morphometrics were used to assess the mechanism of insertion trauma and to determine electrode position within the modiolus. Results: Histological examination revealed varying degrees of damage to the spiral ligament, basilar membrane, and osseous spiral lamina. Using a novel grading system for electrode trauma, there was no statistically significant difference among the three electrodes. A literature search of histological studies of a commonly used "standard" electrode showed damage equal to or greater than that seen in the current study. Conclusions: Insertion trauma caused by periomodiolar electrodes occurs to an acceptable degree. Refinement of electrodes based on mechanisms of trauma may be able to further reduce damage.
Cochlear Implants International, 2004
Objectives To list the complications encountered in a series of 844 consecutive patients and to evaluate the long-term difference in wound and flap problems between large and small incisions. Patients 844 consecutive patients underwent cochlear implantation at the Sydney Cochlear Implant Centre. 212 cases were operated on prior to October 1994 using the retroauricular 'C'-shaped incision or a postauricular incision with a horizontal posterior limb. After October 1994 a new, small vertical postaural incision was used in all patients. Postoperative problems were analysed. Study design Prospective longitudinal study of cochlear implant recipients from1984 to 2003. Setting Te rtiary care referral centre. Intervention Change in incision for cochlear implantation. Main outcome measure Causes of postoperative problems, need for reimplatation, and wound and flap problems. Results 80 out of the total 844 patients underwent revision procedures for various reasons. The commonest cause of reimplantation was device failure (2.01%) or suboptimum performance of the device (2.37%). Wound and flap problems were encountered by 5 patients out of 212 (2.3%) in the first group. In comparison, 7 out of 632 patients (1.10%) from the later group experienced wound and flap problems using the new incision.
Journal of Clinical Medicine
Background: Electrode insertion trauma (EIT) during cochlear implantation (CI) can cause loss of residual hearing. L-N-acetylcysteine (L-NAC) and dexamethasone (Dex) have been individually shown to provide otoprotection albeit at higher concentrations that may be associated with adverse effects. Objective/Aims: The aim of this study is to determine whether L-NAC and Dex could be combined to decrease their effective dosage. Materials and Methods: The organ of Corti (OC) explants were divided into various groups: 1) control; 2) EIT; 3) EIT treated with different concentrations of Dex; 4) EIT treated with different concentrations of L-NAC; 5) EIT treated with L-NAC and Dex in combination. Hair cell (HC) density, levels of oxidative stress, proinflammatory cytokines and nitric oxide (NO) was determined. Results: There was a significant loss of HCs in explants subjected to EIT compared to the control group. L-NAC and Dex in combination was able to provide significant otoprotection at low...
Atraumatic round window deep insertion of cochlear electrodes
Acta Oto-Laryngologica, 2011
Conclusion: This study shows that by using the round window approach and deep insertion, it is possible to reduce electrode insertion trauma (EIT), as indicated by the results of the hearing preservation marker. Objectives: In this prospective study EIT was evaluated in 42 subjects with low frequency hearing before surgery with 28 mm round window deep insertion. Methods: The degree of hearing preservation was a marker of EIT. Pure tone audiometry, monosyllable testing was conducted preoperatively and then at 3, 6, and 13 months after surgery. Results: Immediate hearing preservation (3 months postoperatively) was 92.9% (39/42). The surgery-related hearing preservation 13 months after surgery varied from 85% (34/40) to 90% (36/40). The ipsilateral implanted ear showed significant differences between preoperative and postoperative hearing thresholds (p < 0.005). Comparisons of thresholds for the control ear showed a significant difference between preoperative and postoperative thresholds tested 13 months after surgery (p < 0.05). When the subtraction factor of the mean contralateral hearing loss for each tested frequency for the same time interval was applied to the implanted ear, no significant hearing loss was found, showing that postoperative ipsilateral progressive hearing loss was caused by etiology rather than surgery.
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.