Gentamicin Vestibulotoxicity: Further Insights From a Large Clinical Series.

OBJECTIVE: To review insights gained from a 21-year experience with gentamicin-induced vestibulotoxicity including differences in vestibulotoxicity between single daily dosing (SDD) and multiple daily dosing (MDD) regimens. STUDY DESIGN: Retrospective case series. SETTING: Tertiary care center. PATIENTS: Patients with gentamicin vestibulotoxicity referred to the Hertz Multidisciplinary Neurotology Clinic between January 1993 and September 2014. INTERVENTION: None. MAIN OUTCOME MEASURES: Spectrum of vestibular dysfunction measured using videonystagmography, vestibular evoked myogenic potentials, video head impulse testing, and magnetic scleral search coil testing. RESULTS: Of 53 patients with gentamicin-induced vestibulotoxicity, 24 received SDD and 29 received MDD treatment. The most common indications for treatment were sepsis, endocarditis, and osteomyelitis. Angular acceleration receptor function (semicircular canals) was more commonly affected than linear acceleration receptor function (otolithic organ of the saccule; 100% vs. 62%). A significant proportion of patients (53%) developed vestibulotoxicity in the absence of nephrotoxicity and 40% experienced vestibulotoxicity in a delayed fashion up to 10 days posttreatment cessation (mean 3.9 ±â€Š0.7). Therapeutic monitoring did not necessarily prevent delayed vestibulotoxicity. Nephrotoxicity was less common for SDD compared with MDD (60% vs. 35%, p = 0.01). However, the SDD group experienced vestibulotoxicity at a lower cumulative dose (6.3 vs. 7.0 g, p = 0.04) and shorter duration of therapy (20.7 vs 29.4 d, p = 0.02). CONCLUSIONS: Our study further highlights important insights regarding gentamicin-induced vestibulotoxicity. While SDD is associated with decreased risk for nephrotoxicity compared with MDD, it confers a higher risk for vestibulotoxicity.

Vestibular Outcomes in Bilateral Posterior Semicircular Canal Occlusion for Refractory Benign Positional Vertigo.

INTRODUCTION: Bilateral posterior semicircular canal (PSCC) occlusion is a successful treatment of bilateral benign positional vertigo (BPV) refractory to particle repositioning manoeuvers. Little about the effects on the vestibular ocular reflex (VOR) postoperatively, which is the intent of this study. METHODS: All patients who underwent bilateral posterior canal occlusion for BPV at the University Health Network by the senior author (J.A.R.) between 2001 and 2017 with pre- and postoperative vestibular testing were included in the study.All patients underwent a detailed history and neuro-otological examination including dynamic visual acuity (DVA). Laboratory testing including video head impulse testing or magnetic scleral search coil testing, video nystagmography, cervical and ocular vestibular evoked myogenic potentials and audiological testing before and following their procedure at 1, 6, and 12 months postoperatively. RESULTS: Three patients were included in the study, all females, with a mean age of 41 years (range 36-44 yr). All patients had developed bilateral BPV after head trauma. Mean length of follow-up was 26 months (range 6-84 mo). All patients demonstrated a reduction in the vertical VOR of between 0.37 and 0.57/s at 1 month postocclusion. Between 6 and 12 months postoperatively, an improvement in their vertical VOR between 0.45 and 0.75/s was observed. Clinically, all patients reported complete resolution of their positional vertigo with a negative Dix-Hallpike bilaterally at follow-up. None reported oscillopsia, which was confirmed with DVA testing. CONCLUSION: Bilateral PSCC occlusion results in a reduction in the vertical VOR of the PSCCs.Over a 6 to 12 month time period improvement in the VOR gain can be demonstrated, most likely due to central compensation. There is clinical correlation with improvement in DVA testing. Bilateral PSCC occlusion is a safe and effective treatment for bilateral BPV proved refractory to particle repositioning manoeuvers.

Radiological features for the approach in trans-sphenoidal pituitary surgery.

INTRODUCTION: In order to perform trans-sphenoidal endoscopic pituitary surgery safely and efficiently it is important to identify anatomical and pituitary disease features on the pre-operative CT and MRI scans; thereby minimising the risk to surrounding structures and optimising outcomes. We aim to create a checklist to streamline pre-operative planning. METHODS: We retrospectively reviewed pre-operative CT and MRI scans of 100 adults undergoing trans-sphenoidal endoscopic pituitary surgery. RESULTS: Radiological findings and their incidence included deviated nasal septum (62%), concha bullosa (32%), bony dehiscence of the carotid arteries (18%), sphenoid septation overlying the internal carotid artery (24% at the sella) and low lying CSF (32%). The mean distance of the sphenoid ostium to the skull base was 10 mm (range 2.7-17.6 mm). We also describe the 'teddy bear' sign which when present on an axial CT indicates the carotid arteries will be identifiable intra-operatively. CONCLUSIONS: There are significant variations in the anatomical and pituitary disease features between patients. We describe a number of features on pre-operative scans and have devised a checklist including a new 'teddy bear' sign to aid the surgeon in the anatomical assessment of patients undergoing trans-sphenoidal pituitary surgery.

Inside implant criteria or not? - Detection of non-organic hearing loss during cochlear implant assessment.

OBJECTIVES: The diagnosis of non-organic hearing loss (NOHL) is a difficult but important issue during the assessment process for cochlear implantation (CI). We aim to identify the key factors in identifying patients with NOHL during CI assessment and present our local screening protocol for NOHL. METHODS: A retrospective review of patients referred to the Yorkshire Auditory Implant Service (YAIS) between 2003 and 2015 who were subsequently diagnosed with NOHL during the assessment. Patient demographic data, audiological and functional assessments were assessed. RESULTS: Thirty-two patients were included in the study. Mean age was 43 years (range 14-82 years). Male to female ratio was 1:1.7. Indicators of possible NOHL included a sudden deterioration in hearing (n = 21; 66%), mismatches in observed behaviour and either pure-tone audiogram (PTA) (n = 27; 84%) or functional testing (n = 20; 80%) and stapedial reflexes below reported audiological thresholds (n = 12; 46%). A mismatch in functional hearing and PTA was seen in 72% of patients. Patients with suspected NOHL were referred for further objective testing. All 23 patients who underwent objective testing had better hearing levels compared to reported hearing thresholds thus placing them outside of implant criteria. Five candidates were found to have normal hearing thresholds. DISCUSSION: NOHL can present a significant challenge to the implant team, particularly in the subgroup with a pre-existing organic hearing loss with non-organic overlay. We discuss the common features in this cohort of patients. CONCLUSIONS: To facilitate the identification of patients with NOHL, the YAIS has developed a screening protocol.

Bone-conduction hearing aids in an elderly population: complications and quality of life assessment.

To determine whether an elderly population with hearing impairment can be adequately rehabilitated with a bone-conduction hearing aid and whether the putative relationship between the elderly and an increased complication rate is justified. The study design was a retrospective case note review with a postal and telephone questionnaire, which was carried out in a tertiary centre. All patients aged 60 or over underwent implantation with a bone-conduction aid between 2009 and 2013 for conductive, SSD or mixed hearing loss. Outcome measures were complication rates and quality of life assessment using the Glasgow Benefit Inventory. The influence of patient and surgical factors on the complication rate was assessed. Fifty-one patients were implanted. Mean age was 67 years (range 60-89 years). The mean benefit, satisfaction and global GBI scores were 70 % (range 0-100 %), 70 % (0-100 %) and 82 % (83-100 %), respectively. The residual disability was 18 % (0-25 %). The adverse skin reaction rate was 16 % and the fixture loss rate was 2 %. There was a demonstrable increase in the complication rate with the dermatome (45 %; 5 patients) compared to the Sheffield 'S' (13 %; 2 patients) or linear incision techniques (29 %; 7 patients). The bone-conduction hearing aids are ideal method of hearing rehabilitation in the elderly for all forms of hearing loss. It provides significant benefit with no increased complication rate, which is imperative if social isolation is to be avoided and cognition preserved in this growing elderly population.

Initial UK Experience With a Novel Magnetic Transcutaneous Bone Conduction Device.

OBJECTIVE: To assess outcomes with a new transcutaneous bone conduction hearing aid. PATIENTS: Patients that underwent implantation with the transcutaneous bone conduction device between November 2013 and May 2014. INTERVENTION: Hearing rehabilitation using the BAHA Attract. MAIN OUTCOME MEASURES: Quality of life measures using Glasgow benefit inventory (GBI) and clinically oriented scale of improvement (COSI). Audiological outcome using word discrimination score. RESULTS: Ten patients were implanted. Significant improvement in GBI and COSI scores comparing preimplantation and postimplantation. An increase in word discrimination scores at 30 dBA, with an increase from 0% unaided to a mean of 50% with the magnetic transcutaneous bone conduction aid and at 50 dBA with an increase from a mean of 31.7% to 88.3%. However, the word discrimination score increase at 30, 50, and 60 dBA was not statistically significant (p = 0.25; Wilcoxon). CONCLUSION: There was a high level of satisfaction with the device with significant increases in GBI and COSI scores in patients who were previously aided with an acoustic aid. The absence of daily skin hygiene appealed to patients.

Analysis of radiation-induced cell death in head and neck squamous cell carcinoma and rat liver maintained in microfluidic devices.

OBJECTIVE: The aim of this study was to investigate how head and neck squamous cell carcinoma (HNSCC) tissue biopsies maintained in a pseudo in vivo environment within a bespoke microfluidic device respond to radiation treatment. STUDY DESIGN: Feasibility study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Thirty-five patients with HNSCC were recruited, and liver tissue from 5 Wistar rats was obtained. A microfluidic device was used to maintain the tissue biopsy samples in a viable state. Rat liver was used to optimize the methodology. HNSCC was obtained from patients with T1-T3 laryngeal or oropharyngeal SCC; N1-N2 metastatic cervical lymph nodes were also obtained. Irradiation consisted of single doses of between 2 Gy and 40 Gy and a fractionated course of 5×2 Gy. Cell death was assessed in the tissue effluent using the soluble markers lactate dehydrogenase (LDH) and cytochrome c and in the tissue by immunohistochemical detection of cleaved cytokeratin18 (M30 antibody). RESULTS: A significant surge in LDH release was demonstrated in the rat liver after a single dose of 20 Gy; in HNSCC, it was seen after 40 Gy compared with the control. There was no significant difference in cytochrome c release after 5 Gy or 10 Gy. M30 demonstrated a dose-dependent increase in apoptotic index for a given increase in single-dose radiotherapy. There was a significant increase in apoptotic index between 1×2 Gy and 5×2 Gy. CONCLUSION: M30 is a superior method compared with soluble markers in detecting low-dose radiation-induced cell death. This microfluidic technique can be used to assess radiation-induced cell death in HNSCC and therefore has the potential to be used to predict radiation response.

Upper limb dysfunction following selective neck dissection: a retrospective questionnaire study.

BACKGROUND: To determine total upper limb function following selective neck dissection over a mean follow-up of 1.6 years. METHODS: A retrospective questionnaire study in a tertiary head and neck surgical unit. One hundred forty-eight patients who underwent selective neck dissection for head and neck cancer from January 2000 to December 2005 were invited to participate. The main outcome measure was ipsilateral upper limb dysfunction as measured by the Disability of Arm, Shoulder and Hand (DASH) questionnaire. RESULTS: Sixty-five patients responded to the invitation to join the study from 148 invited. Despite accessory nerve conserving surgery for all the selective neck dissections studied, 23% reported no upper limb dysfunction, 54% reported mild upper limb dysfunction, 15% reported moderate, and 8% reported a severe dysfunction. CONCLUSIONS: Long-term upper limb dysfunction is common following nerve preserving surgery. The DASH questionnaire is a useful preoperative and postoperative clinical tool for those patients undergoing selective neck dissections.