J. Thomas Roland

Histopathology of Cochlear Implants in Humans

The insertion of an intrascalar electrode array during cochlear implantation causes immediate damage to the inner ear and may result in delayed onset of additional damage that may interfere with neuronal stimulation. To date, there have been reports on fewer than 50 temporal bone specimens from patients who had undergone implantation during life. The majority of these were single-channel implants, whereas the majority of implants inserted today are multichannel systems. This report presents the histopathologic findings in temporal bones from 8 individuals who in life had undergone multichannel cochlear implantation, with particular attention to the type and location of trauma and to long-term changes within the cochlea. The effect of these changes on spiral ganglion cell counts and the correlation between speech comprehension and spiral ganglion cell counts were calculated. In 4 of the 8 cases, the opposite, unimplanted ear was available for comparison. In 3 of the 4 cases, there was no significant difference between the spiral ganglion cell counts on the implanted and unimplanted sides. In addition, in this series of 8 cases, there was an apparent negative correlation between residual spiral ganglion cell count and hearing performance during life as measured by single-syllable word recognition. This finding suggests that abnormalities in the central auditory pathways are at least as important as spiral ganglion cell loss in limiting the performance of implant users.

Validation of the Charlson Comorbidity Index in Patients With Head and Neck Cancer: A Multi‐institutional Study

Comorbid conditions are medical illnesses that accompany cancer. The impact of these conditions on the outcome of patients with head and neck cancer is well established. However, all of the comorbidity studies in patients with head and neck cancer reported in the literature have been performed using the Kaplan‐Feinstein index (KFI), which may be too complicated for routine use. This study was performed to introduce and validate the use of the Charlson comorbidity index (CI) in patients with head and neck cancer and to compare it with the Kaplan‐Feinstein comorbidity index for accuracy and ease of use. Study design was a retrospective cohort study. The study population was drawn for three academic tertiary care centers and included 88 patients 45 years of age and under who underwent curative treatment for head and neck cancer. All patients were staged by the KFI and the CI for comorbidity and divided into two groups based on the comorbidity severity staging. Group 1 included patients with advanced comorbidity (stages 2 or 3), and group 2 included those with low‐level comorbidity (stages 0 or 1). Outcomes were compared based on these divisions. The KFI was successfully applied to 80% of this study population, and the CI was successfully applied in all cases ( P < 0.0001). In addition, the KFI was found to be more difficult to use than the CI ( P < 0.0001). However, both indices independently predicted the tumor‐specific survival ( P = 0.007), even after adjusting for the confounding effects of TNM stage by multivariate analysis. Overall, the CI was found to be a valid prognostic indicator in patients with head and neck cancer. In addition, because comorbidity staging by the CI independently predicted survival, was easier to use, and more readily applied, it may be better suited for use for retrospective comorbidity studies.

A Model for Cochlear Implant Electrode Insertion and Force Evaluation: Results with a New Electrode Design and Insertion Technique

Objectives and Hypothesis: This study has the specific aim of evaluating the insertion characteristics of a new cochlear implant electrode. Techniques for evaluation of fluoroscopic real time mechanical insertion dynamics, histologic electrode position and trauma results, hydraulic force, and mechanical insertion forces are presented. In addition, this study should serve to present a novel model for cochlear implant electrode insertion evaluations.

Long-term effects of cochlear implants in children

OBJECTIVE: Since 1987, when the use of multichannel cochlear implants was initiated in children, candidacy has expanded; many thousands of children have received these devices, and results have revealed a wide range of performance. However, few long-term studies exist on a large population of these children. There have been concerns expressed that cochlear implant function might degrade over time, that devices and electrodes might migrate and extrude in the growing child, or that there might even be a deleterious effect of long-term stimulation of the cochlear nerve. The purpose of this study was to explore the long-term effects of implantation as a function of performance over time, reimplantation, and educational factors. STUDY DESIGN AND SETTING: We studied 81 children who received implants at a major academic medical center and were followed for 5 to 13 years. RESULTS: Results revealed significant gains in speech perception, use of oral language, and ability to function in a mainstream environment. There was no decrease in performance over time and no significant incidence of device or electrode migration or extrusion, and device failure did not cause a deterioration in long-term outcome. CONCLUSIONS: Multichannel cochlear implants in children provide perception, linguistic, and educational advantages, which are not adversely affected by long-term electrical stimulation.

Impact of comorbidity on outcome of young patients with head and neck squamous cell carcinoma

Comorbid conditions have a significant impact on the actuarial survival of patients with head and neck cancer. However, no studies have evaluated the impact of comorbidity on tumor‐ and treatment‐specific outcomes. This study was performed to evaluate the impact of comorbidity, graded by the Kaplan‐Feinstein comorbidity index (KFI) on the incidence and severity of complications, disease‐free interval, and tumor‐specific survival in patients undergoing curative treatment for head and neck cancer.

A temporal bone study of insertion trauma and intracochlear position of cochlear implant electrodes. I: Comparison of Nucleus banded and Nucleus Contour electrodes.

In recent years, new designs of cochlear implant electrodes have been introduced in an attempt to improve efficiency and performance by locating stimulation sites closer to spiral ganglion neurons and deeper into the scala tympani. The goal of this study was to document insertion depth, intracochlear position and insertion trauma with the Nucleus Contour electrode and to compare results to those observed with the earlier generation Nucleus banded electrode. For this comparison eight Nuclears banded electrodes and 18 Contour electrodes were implanted in cadaver temporal bones using a realistic surgical exposure. Two experienced cochlear implant surgeons and two otology fellows with specialized training in cochlear implant surgery were selected for the study to represent a range of surgical experience similar to that of surgeons currently performing the procedure throughout the world. Following insertion of the electrodes, specimens were imaged using plain film X-ray, embedded in acrylic resin, cut in radial sections with the electrodes in place, and each cut surface was polished. Insertion depth was measured in digitized X-ray images, and trauma was assessed in each cross-section. The Contour electrode inserted more deeply (mean depth=17.9 mm or 417 degrees ) than the banded electrode (mean depth=15.3 mm or 285 degrees ). The incidence and severity of trauma varied substantially among the temporal bones studied. However, the nature and frequency of injuries observed with the two devices were very similar. The Contour electrode was clearly positioned closer to the modiolus than the banded model, and also appeared easier to use. Based on this difference in position and data from previous studies we conclude that the Contour electrode may provide lower thresholds and improved channel selectivity, but the incidence of trauma remains a problem with the newer design. The relative influences of electrode positioning and neural degeneration that may result from trauma are as yet unclear.

Speech perception benefits of sequential bilateral cochlear implantation in children and adults: a retrospective analysis.

Objective: To examine speech perception outcomes and determine the impact of length of deafness and time between implants on performance in the sequentially bilateral implanted population. Study Design: Retrospective review. Setting: Tertiary academic referral center. Patients: Forty-three children (age, <18 yr) and 22 adults underwent sequential bilateral implantation with at least 6 months between surgeries. The mean age at the time of the second implant in children was 7.83 years, and mean time between implants was 5.16 years. Five children received the first side implant (C1) below 12 months of age; 16, at 12 to 23 months; 9, between the ages of 24 and 35 months; and 11, at 36 to 59 months; 2 were implanted above the age of 5 years. In adults, mean age at second implant was 46.6 years, and mean time between implants was 5.6 years. Intervention: Sequential implantation with 6 months or more between implantations. Main Outcome Measures: Speech perception tests were performed preoperatively before the second implantation and at 3 months postoperatively. Results: Results revealed significant improvement in the second implanted ear and in the bilateral condition, despite time between implantations or length of deafness; however, age of first-side implantation was a contributing factor to second ear outcome in the pediatric population. Conclusion: Sequential bilateral implantation leads to significantly better speech understanding. On average, patients improved, despite length of deafness, time between implants, or age at implantation.

Cochlear Reimplantation: Surgical Techniques and Functional Results

Objectives/Hypothesis The most common indication for cochlear reimplantation is device failure. Other, less frequent indications consist of “upgrades” (e.g., single to multichannel), infection, and flap breakdown. Although the percentage of failures has decreased over time, an occasional patient requires reimplantation because of device malfunction. The varying designs of internal receiver/stimulators and electrode arrays mandate an examination of the nature and effects of reimplantation for the individual designs. The purpose of the current study was to investigate the reimplantation of several implant designs and to determine whether differences in surgical technique, anatomical findings, and postoperative performance exist.

Delayed implantation in congenitally deaf children and adults.

Objective To determine the efficacy of cochlear implants with current processing strategies in children and adults with long-term congenital deafness, and to determine whether the growth of auditory perceptual skills in these patients is similar to the data reported for patients who have undergone implantation with earlier devices and coding strategies. Study Design A prospective study of children and adults fulfilling the study inclusion criteria. Setting University medical center. Patients Thirty-five congenitally deaf children who received implants after the age of 8 years and 14 congenitally deaf adults who received implants as adults participated in this study. Length of device use ranged from 6 months to 3 years. Main Outcome Measures Open set phoneme, word recognition tests, and sentence recognition tests were administered in quiet and noise auditory only conditions preoperatively and postoperatively. Changes in test scores were examined by paired t tests, and differences between groups were compared by Students t tests. Spearman correlation coefficients were calculated to identify associations between scores and subject characteristics. A two-sided &agr; of less than 0.05 was considered statistically significant. Results The results indicated significant improvement in open set speech perception skills in the children after implantation; the adults demonstrated improved mean scores on both word and sentence recognition. A shorter length of deafness correlated with better postoperative performance, but all subjects continued to improve over time. The improvement in test scores was similar between the devices, and no significant differences were detected between the different processing strategies. Conclusion Children and adults with long-term congenital deafness can obtain considerable open set speech understanding after implantation. Length of deafness (age at implantation), length of device use, and mode of communication contribute to outcome.

Paradoxical spread of renal cell carcinoma to the head and neck

Objectives: To present cases of renal cell carcinoma presenting with only head and neck metastases, to review theories of physiology and anatomy describing this phenomenon, and to discuss the role of the otolaryngologist in the treatment of these lesions. Study Design: Retrospective review of the records of three patients who presented with renal cell carcinoma with head and neck metastases over the 3‐year period from 1992 to 1995. Methods: Retrospective review of the records of three patients who presented with renal cell carcinoma with head and neck metastases. In addition, English‐language literature was reviewed with special focus on the anatomic and physiologic pathways possible to allow for such a phenomenon. Conclusions: Renal cell carcinoma has an occasional presentation as a head and neck mass without evidence of disease elsewhere. Various routes of spread have been postulated. Batsons venous plexus, as postulated by Nahum and Bailey, 2 is an anatomic route through which emboli could navigate to the head and neck and avoid pulmonary vascular filtration. Interactions on the cellular level may also be responsible for the seemingly paradoxical spread. We recommend local excision of head and neck metastases of renal cell carcinoma without sacrifice of vital structures as a sound treatment regimen.