Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, Jan 20, 2015
(1) To investigate the outcomes of cochlear implant receiver-stimulator (RS) placement using a ti... more (1) To investigate the outcomes of cochlear implant receiver-stimulator (RS) placement using a tight subperiosteal pocket technique without device fixation and (2) to compare the efficiency of this approach with the traditional bony well and trough technique. Case series with planned chart review. Single tertiary academic referral center. All cochlear implant surgeries utilizing a tight subperiosteal pocket without additional fixation or use of a bone well were identified retrospectively. Revision cases were only included if the tight subperiosteal pocket technique was used during the initial surgery. Patients with less than 6 months of postoperative follow-up were excluded. Primary outcome measures included RS migration, flap complications, device failure, and percentage reduction in operative time. Two hundred twenty-eight cases (average age 45.3 years) met inclusion criterion and were analyzed. At a mean follow-up of 18.1 months, no patient experienced RS migration. One patient experienced a postoperative hematoma that was managed with observation. One patient developed a surgical site infection that resolved following exploration and intravenous antibiotics. The subperiosteal pocket technique resulted in an 18.9% reduction in total operative time compared to a more conventional RS placement method (P < .01). The tight subperiosteal pocket without fixation is a safe, durable, and time-saving technique for RS placement during cochlear implantation. Notably, device migration and flap complications are very uncommon.
To date, the majority of the vestibular schwannoma (VS) literature has focused on tumor control r... more To date, the majority of the vestibular schwannoma (VS) literature has focused on tumor control rates, facial nerve function and hearing preservation. Other factors that have been shown to significantly affect quality-of-life (QOL), such as dizziness, remain understudied. The primary objective of the current study is to investigate the association between radiation dose to the vestibule and post-treatment changes in vestibular function and patient reported dizziness handicap. This is a prospective observational pilot study at a tertiary academic referral center including all subjects that underwent linear accelerator-based stereotactic radiotherapy (SRS) for sporadic VS and completed pre-treatment and post-treatment vestibular testing and Dizziness Handicap Inventory (DHI) questionnaires. Associations between objective vestibular test results, patient-reported DHI scores and radiation dose parameters were investigated. Ten patients met inclusion criteria. Tumor control was achieved in all individuals. There were no statistically significant associations or identifiable trends between radiation dose and change in vestibular function or DHI scores. Notably, the four ears receiving the highest vestibular dose had minimal changes in vestibular function tests and DHI scores. To the best of our knowledge, no previous reports have described the association between radiation dose to the vestibule and post-treatment changes in vestibular function and patient reported DHI. Based on these preliminary data, radiation dose to the vestibule does not reliably predict change in objective or subjective vestibular outcome measures.
Afferent synapses on inner hair cells (IHC) transfer auditory information to the central nervous ... more Afferent synapses on inner hair cells (IHC) transfer auditory information to the central nervous system (CNS). Despite the importance of these synapses for normal hearing, their response to cochlear disease and dysfunction is not well understood. The C57BL/6J mouse is a model for presbycusis and noise-induced hearing loss because of its age-related hearing loss and susceptibility to acoustic over-exposure. In
To identify early predictors of long-term facial nerve function after vestibular schwannoma resec... more To identify early predictors of long-term facial nerve function after vestibular schwannoma resection. Retrospective chart review. Tertiary referral center. Subjects with facial nerve weakness despite anatomic preservation of the nerve after removal of vestibular schwannoma. Surgical resection of vestibular schwannoma. Facial function after 1 postoperative year. Independent variables included patient demographics, presenting symptoms, tumor size and location, and serial postoperative function within the first year. Among 281 patients with postoperative facial weakness, 81% improved to a House-Brackmann (HB) III or better (good outcome) after 12 months of recovery, whereas 12% remained HB IV or worse (poor outcome). For patients starting with HB V or VI function, recovery rate was the most reliable predictor of poor outcome after 1 year. The resulting predictive model using rate of functional improvement as the independent variable was found to anticipate poor outcome before 1 year in more than 50% of cases with 97% sensitivity and 97% specificity. Although associated with facial nerve outcome, tumor size, tumor vascularity, preoperative facial function, age at surgery, and ability to stimulate the nerve intraoperatively did not contribute significantly to the predictive model. The rate of recovery within the first postoperative year serves as a useful early predictor of long-term facial nerve function. We present a novel predictive model using rate of recovery that can be used to select candidates for reanimation surgery sooner than the traditional waiting period of 1 year, potentially improving the outcome of this intervention.
Mice lacking functional KCNQ1 (previously known as KvLQT1) channels exhibit functional and struct... more Mice lacking functional KCNQ1 (previously known as KvLQT1) channels exhibit functional and structural abnormalities that indicate disturbed production of endolymph. Congenital deafness associated with cardiac conduction abnormalities (Jervell and Lange-Nielsen syndrome) is associated with dysfunctional KCNQ1/KCNE1 channel complex. This potassium channel plays a critical role in the production and homeostasis of endolymph by the stria vascularis. A preliminary report documented severe abnormalities of the scala media and vestibular compartments of a single mouse lacking functional KCNQ1 alleles. Hearing thresholds were measured in three Kcnq1 knockout mice, two heterozygous mice, and one wild-type mouse by auditory brainstem response recordings using clicks, after which the temporal bones were removed. After fixation and dehydration, the ears were embedded in araldite, sectioned at 20-microm thickness, stained with toluidine blue on glass slides, and examined with the light microscope. Kcnq1 knockout mice were deaf and demonstrated circling behavior. They exhibited a marked atrophy of the stria vascularis, contraction of the endolymphatic compartments, and collapse and adhesion of surrounding membranes. There was a complete degeneration of the organ of Corti and an associated degeneration of the spiral ganglion. Kcnq1 knockout mice exhibit histopathologic findings that are comparable to those reported in human temporal bone cases of Jervell and Lange-Nielsen syndrome, and provide further evidence that KCNQ1 channel dysfunction can lead to congenital deafness in this syndrome.
To assess the efficacy, risks, and indications of revision cochlear implantation (RCI) and to ide... more To assess the efficacy, risks, and indications of revision cochlear implantation (RCI) and to identify the clinical, audiologic, and device-related characteristics that predict outcome. Retrospective case series. Academic tertiary referral center. Adults (> or = 18 yr) who underwent RCI at Johns Hopkins University. Revision cochlear implant surgery. Speech perception by open-set testing and patient report and patient report of symptom resolution. During the 16-year period of this study, 4.8% of all adults implanted at our center have required 1 or more RCI surgeries. A total of 48 RCIs have been performed. The indications for RCI included infection (12%), electrode extrusion (15%), hard failure (23%), suspected device failure (42%), and isolated facial nerve stimulation (8%). Overall, successful resolution of the implant-related or medical condition was achieved with RCI in 83% of cases. Speech perception was lower in only 1 (2.1%) of 48 cases. Satisfactory preoperative speech recognition was preserved or surpassed in 5 of 6 infection cases and 8 cases with progressive symptoms of tinnitus and facial nerve stimulation. All cases of hard failure regained or surpassed previous peak performance. Improved speech recognition was experienced by 75% of cases with suspected device failure. Of cases in which RCI failed to restore previous functional benefit, there was a significant association with advanced age (> 70 yr). Whereas an abnormal integrity test was predictive of favorable outcome after RCI, a negative test was not predictive of outcome. A similar pattern of results was observed with respect to ex vivo device analysis. Revision cochlear implantation can be safely performed to restore lost benefit in appropriately selected cases. When properly performed after medical and audiologic options have been exhausted, RCI rarely compromises previous function and, in most cases, can resolve functional complaints and distracting symptoms. When positive, integrity testing is a useful screen for the presence of a device defect. In cases in which device integrity is uncertain, clinical judgment guided by longitudinal assessment can help determine whether RCI is likely to be beneficial.
To demonstrate the added value of magnetic resonance imaging (MRI) over computed tomography (CT) ... more To demonstrate the added value of magnetic resonance imaging (MRI) over computed tomography (CT) during adult cochlear implant evaluation. Two adult patients are discussed in whom MRI studies diagnosed bilateral vestibular schwannomas during cochlear implant candidacy evaluation. Temporal bone CT and MRI. Diagnosis of NF2. Two adult patients, ages 67 and 68 years, were evaluated for cochlear implant candidacy. Both patients experienced slowly progressive, bilateral hearing loss without complaints of vertigo, and neither patient had a family history of hearing loss or neurogenic tumors. Both patients had near-symmetric pure tone thresholds on audiometric testing. An MRI and a CT scan were performed on both patients, and bilateral vestibular schwannomas were identified on MRI. Though MRI is not routinely utilized in adult cochlear implant evaluation, it may be of greater clinical value than CT in the setting of adult-onset hearing loss. MRI allows for sensitive evaluation of cochlear patency and architecture, and cochlear nerve status. As demonstrated in the two index cases, MRI also provides the added benefit of evaluating for causes of retrocochlear hearing loss. These two patients would have likely experienced a significant delay in diagnosis of NF2 without preoperative MRI, particularly given the limitations of scanning following CI magnet placement.
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2014
To evaluate tumor control following subtotal resection of advanced jugular paragangliomas in pati... more To evaluate tumor control following subtotal resection of advanced jugular paragangliomas in patients with functional lower cranial nerves and to investigate the utility of salvage radiotherapy for residual progressive disease. Case series with planned chart review. Tertiary academic referral center. Patients who presented with advanced jugular paragangliomas and functional lower cranial nerves were analyzed. Primary outcome measures included extent of resection, long-term tumor control, need for additional treatment, and postoperative lower cranial nerve function. Twelve patients (mean age, 46.2 years; 7 women, 58.3%) who met inclusion criteria were evaluated between 1999 and 2013. The mean postoperative residual tumor volume was 27.7% (range, 3.5%-75.0%) of the preoperative volume. When the residual tumor volume was less than 20% of the preoperative volume, no tumor growth occurred over an average of 44.6 months of follow-up (P < .01). Four tumors (33.3%) demonstrated serial gr...
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, Jan 20, 2015
(1) To investigate the outcomes of cochlear implant receiver-stimulator (RS) placement using a ti... more (1) To investigate the outcomes of cochlear implant receiver-stimulator (RS) placement using a tight subperiosteal pocket technique without device fixation and (2) to compare the efficiency of this approach with the traditional bony well and trough technique. Case series with planned chart review. Single tertiary academic referral center. All cochlear implant surgeries utilizing a tight subperiosteal pocket without additional fixation or use of a bone well were identified retrospectively. Revision cases were only included if the tight subperiosteal pocket technique was used during the initial surgery. Patients with less than 6 months of postoperative follow-up were excluded. Primary outcome measures included RS migration, flap complications, device failure, and percentage reduction in operative time. Two hundred twenty-eight cases (average age 45.3 years) met inclusion criterion and were analyzed. At a mean follow-up of 18.1 months, no patient experienced RS migration. One patient experienced a postoperative hematoma that was managed with observation. One patient developed a surgical site infection that resolved following exploration and intravenous antibiotics. The subperiosteal pocket technique resulted in an 18.9% reduction in total operative time compared to a more conventional RS placement method (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .01). The tight subperiosteal pocket without fixation is a safe, durable, and time-saving technique for RS placement during cochlear implantation. Notably, device migration and flap complications are very uncommon.
To date, the majority of the vestibular schwannoma (VS) literature has focused on tumor control r... more To date, the majority of the vestibular schwannoma (VS) literature has focused on tumor control rates, facial nerve function and hearing preservation. Other factors that have been shown to significantly affect quality-of-life (QOL), such as dizziness, remain understudied. The primary objective of the current study is to investigate the association between radiation dose to the vestibule and post-treatment changes in vestibular function and patient reported dizziness handicap. This is a prospective observational pilot study at a tertiary academic referral center including all subjects that underwent linear accelerator-based stereotactic radiotherapy (SRS) for sporadic VS and completed pre-treatment and post-treatment vestibular testing and Dizziness Handicap Inventory (DHI) questionnaires. Associations between objective vestibular test results, patient-reported DHI scores and radiation dose parameters were investigated. Ten patients met inclusion criteria. Tumor control was achieved in all individuals. There were no statistically significant associations or identifiable trends between radiation dose and change in vestibular function or DHI scores. Notably, the four ears receiving the highest vestibular dose had minimal changes in vestibular function tests and DHI scores. To the best of our knowledge, no previous reports have described the association between radiation dose to the vestibule and post-treatment changes in vestibular function and patient reported DHI. Based on these preliminary data, radiation dose to the vestibule does not reliably predict change in objective or subjective vestibular outcome measures.
Afferent synapses on inner hair cells (IHC) transfer auditory information to the central nervous ... more Afferent synapses on inner hair cells (IHC) transfer auditory information to the central nervous system (CNS). Despite the importance of these synapses for normal hearing, their response to cochlear disease and dysfunction is not well understood. The C57BL/6J mouse is a model for presbycusis and noise-induced hearing loss because of its age-related hearing loss and susceptibility to acoustic over-exposure. In
To identify early predictors of long-term facial nerve function after vestibular schwannoma resec... more To identify early predictors of long-term facial nerve function after vestibular schwannoma resection. Retrospective chart review. Tertiary referral center. Subjects with facial nerve weakness despite anatomic preservation of the nerve after removal of vestibular schwannoma. Surgical resection of vestibular schwannoma. Facial function after 1 postoperative year. Independent variables included patient demographics, presenting symptoms, tumor size and location, and serial postoperative function within the first year. Among 281 patients with postoperative facial weakness, 81% improved to a House-Brackmann (HB) III or better (good outcome) after 12 months of recovery, whereas 12% remained HB IV or worse (poor outcome). For patients starting with HB V or VI function, recovery rate was the most reliable predictor of poor outcome after 1 year. The resulting predictive model using rate of functional improvement as the independent variable was found to anticipate poor outcome before 1 year in more than 50% of cases with 97% sensitivity and 97% specificity. Although associated with facial nerve outcome, tumor size, tumor vascularity, preoperative facial function, age at surgery, and ability to stimulate the nerve intraoperatively did not contribute significantly to the predictive model. The rate of recovery within the first postoperative year serves as a useful early predictor of long-term facial nerve function. We present a novel predictive model using rate of recovery that can be used to select candidates for reanimation surgery sooner than the traditional waiting period of 1 year, potentially improving the outcome of this intervention.
Mice lacking functional KCNQ1 (previously known as KvLQT1) channels exhibit functional and struct... more Mice lacking functional KCNQ1 (previously known as KvLQT1) channels exhibit functional and structural abnormalities that indicate disturbed production of endolymph. Congenital deafness associated with cardiac conduction abnormalities (Jervell and Lange-Nielsen syndrome) is associated with dysfunctional KCNQ1/KCNE1 channel complex. This potassium channel plays a critical role in the production and homeostasis of endolymph by the stria vascularis. A preliminary report documented severe abnormalities of the scala media and vestibular compartments of a single mouse lacking functional KCNQ1 alleles. Hearing thresholds were measured in three Kcnq1 knockout mice, two heterozygous mice, and one wild-type mouse by auditory brainstem response recordings using clicks, after which the temporal bones were removed. After fixation and dehydration, the ears were embedded in araldite, sectioned at 20-microm thickness, stained with toluidine blue on glass slides, and examined with the light microscope. Kcnq1 knockout mice were deaf and demonstrated circling behavior. They exhibited a marked atrophy of the stria vascularis, contraction of the endolymphatic compartments, and collapse and adhesion of surrounding membranes. There was a complete degeneration of the organ of Corti and an associated degeneration of the spiral ganglion. Kcnq1 knockout mice exhibit histopathologic findings that are comparable to those reported in human temporal bone cases of Jervell and Lange-Nielsen syndrome, and provide further evidence that KCNQ1 channel dysfunction can lead to congenital deafness in this syndrome.
To assess the efficacy, risks, and indications of revision cochlear implantation (RCI) and to ide... more To assess the efficacy, risks, and indications of revision cochlear implantation (RCI) and to identify the clinical, audiologic, and device-related characteristics that predict outcome. Retrospective case series. Academic tertiary referral center. Adults (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or = 18 yr) who underwent RCI at Johns Hopkins University. Revision cochlear implant surgery. Speech perception by open-set testing and patient report and patient report of symptom resolution. During the 16-year period of this study, 4.8% of all adults implanted at our center have required 1 or more RCI surgeries. A total of 48 RCIs have been performed. The indications for RCI included infection (12%), electrode extrusion (15%), hard failure (23%), suspected device failure (42%), and isolated facial nerve stimulation (8%). Overall, successful resolution of the implant-related or medical condition was achieved with RCI in 83% of cases. Speech perception was lower in only 1 (2.1%) of 48 cases. Satisfactory preoperative speech recognition was preserved or surpassed in 5 of 6 infection cases and 8 cases with progressive symptoms of tinnitus and facial nerve stimulation. All cases of hard failure regained or surpassed previous peak performance. Improved speech recognition was experienced by 75% of cases with suspected device failure. Of cases in which RCI failed to restore previous functional benefit, there was a significant association with advanced age (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 70 yr). Whereas an abnormal integrity test was predictive of favorable outcome after RCI, a negative test was not predictive of outcome. A similar pattern of results was observed with respect to ex vivo device analysis. Revision cochlear implantation can be safely performed to restore lost benefit in appropriately selected cases. When properly performed after medical and audiologic options have been exhausted, RCI rarely compromises previous function and, in most cases, can resolve functional complaints and distracting symptoms. When positive, integrity testing is a useful screen for the presence of a device defect. In cases in which device integrity is uncertain, clinical judgment guided by longitudinal assessment can help determine whether RCI is likely to be beneficial.
To demonstrate the added value of magnetic resonance imaging (MRI) over computed tomography (CT) ... more To demonstrate the added value of magnetic resonance imaging (MRI) over computed tomography (CT) during adult cochlear implant evaluation. Two adult patients are discussed in whom MRI studies diagnosed bilateral vestibular schwannomas during cochlear implant candidacy evaluation. Temporal bone CT and MRI. Diagnosis of NF2. Two adult patients, ages 67 and 68 years, were evaluated for cochlear implant candidacy. Both patients experienced slowly progressive, bilateral hearing loss without complaints of vertigo, and neither patient had a family history of hearing loss or neurogenic tumors. Both patients had near-symmetric pure tone thresholds on audiometric testing. An MRI and a CT scan were performed on both patients, and bilateral vestibular schwannomas were identified on MRI. Though MRI is not routinely utilized in adult cochlear implant evaluation, it may be of greater clinical value than CT in the setting of adult-onset hearing loss. MRI allows for sensitive evaluation of cochlear patency and architecture, and cochlear nerve status. As demonstrated in the two index cases, MRI also provides the added benefit of evaluating for causes of retrocochlear hearing loss. These two patients would have likely experienced a significant delay in diagnosis of NF2 without preoperative MRI, particularly given the limitations of scanning following CI magnet placement.
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2014
To evaluate tumor control following subtotal resection of advanced jugular paragangliomas in pati... more To evaluate tumor control following subtotal resection of advanced jugular paragangliomas in patients with functional lower cranial nerves and to investigate the utility of salvage radiotherapy for residual progressive disease. Case series with planned chart review. Tertiary academic referral center. Patients who presented with advanced jugular paragangliomas and functional lower cranial nerves were analyzed. Primary outcome measures included extent of resection, long-term tumor control, need for additional treatment, and postoperative lower cranial nerve function. Twelve patients (mean age, 46.2 years; 7 women, 58.3%) who met inclusion criteria were evaluated between 1999 and 2013. The mean postoperative residual tumor volume was 27.7% (range, 3.5%-75.0%) of the preoperative volume. When the residual tumor volume was less than 20% of the preoperative volume, no tumor growth occurred over an average of 44.6 months of follow-up (P < .01). Four tumors (33.3%) demonstrated serial gr...
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Papers by Alejandro Rivas