James Lin

Optical Coherence Tomography Imaging of the Inner Ear: A Feasibility Study with Implications for Cochlear Implantation

Cochlear implantation is now being performed in ears with residual hearing. Those implant recipients who keep residual hearing may benefit from improved pitch resolution through both electrical and acoustic hearing. Preservation of cochlear function after implantation is a challenging task for the surgeon. Current topics of hearing preservation research include electrode design and surgical technique. To maintain hearing, surgeons strive to create a cochleostomy and place the electrode in a minimally traumatic fashion. In this study, we examine a novel catheter-based real-time imaging modality with 10- to 15-μm resolution, optical coherence tomography (OCT), on the inner ear. We demonstrate the capability of OCT to allow visualization of inner ear structures through bone in live mice. We additionally used OCT to image the inner ear in a human temporal bone. Optical coherence tomography was able to delineate soft tissue structures within the cochlea and may be useful as an adjunct to cochlear implantation. Other potential otologic applications of OCT are discussed.

Conservative management of vestibular schwannoma: expectations based on the length of the observation period.

Objective Evaluate long-term prevalence of tumor growth and need for further treatment in patients with a vestibular schwannoma treated with conservative management. Study Design Retrospective chart review. Setting Private neurotologic tertiary referral center. Patients Vestibular schwannoma patients undergoing conservative management and previously studied (N = 114). Mean time to last magnetic resonance imaging was 4.8 years and to last follow-up was 6.4 years (maximum, 18.5 yr). Intervention Serial gadolinium-enhanced magnetic resonance imaging with size measurement. Main Outcome Measures Change in maximum tumor dimension of 2 mm or higher (growth), further treatment, audiologic measures—pure-tone average, word recognition, AAO-HNS (American Academy of Otolaryngology-Head and Neck Surgery) hearing class. Results Thirty-eight percent of tumors demonstrated growth; an average of 6.5 mm (SD, 3.8) at a mean rate of 3.1 mm per year. Of patients with no growth at 1 year or less, 20% grew by last follow-up. Overall, 31% had further treatment after a mean of 3.8 years (SD, 3.5; maximum, 18.5 yr). Of those followed for 5 to 10 years, 18% eventually had further treatment. Only 56% of growing tumors had further treatment by last follow-up; 14.8% with nongrowing tumors also had further treatment. Pure-tone average declined more in tumors that grew (mean &Dgr; = 28.8 dB) than those that did not (mean &Dgr; = 16.5 dB) (p ⩽ 0.025), but there was no correlation between the amount of change in hearing and in the size of the tumor. Of patients with an initial AAO-HNS hearing Class A, 85.7% retained serviceable hearing. Conclusion For patients electing an observation approach to treatment of vestibular schwannoma, about 31% may eventually undergo further treatment. Of those followed for 5 to 10 years, 18% eventually had further treatment. However, some patients are followed with radiologic evaluations for many years without necessity for further treatment.

Psychiatric symptoms with initiation of carbidopa‐levodopa treatment

Two patients who had had no previous psychiatric symptoms became psychotic after their antiparkinsonism medication was changed from levodopa alone to a combination of levodopa and carbidopa, despite adherence to the appropriate and recommended dosage. Psychiatric symptoms disappeared after treatment with levodopa alone was resumed.

Lymphocyte studies in a patient with chronic polyradiculoneuropathy

We studied immunologic abnormalties in one patient with chronic polyradiculoneuropathy and the effects of immune suppression and plasmapheresis on the clinical course and immune abnormalities. Increased helper T cells and B cells with deficiency of T suppressor cells to B-cell but not to T-cell targets were detected. The patients blood lymphocytes, but not the controls lymphocytes, proliferated in vitro on culturing them with P2 antigen in the presence of the patients CSF. Plasmapheresis combined with corticosteroid and azathioprine reversed the majority of immune abnormalities to normal but did not decrease the patients lymphocyte-P2 proliferative response; nor did it improve clinical status.

Impact of Diabetic Complications on Balance and Falls: Contribution of the Vestibular System

Diabetes causes many complications, including retinopathy and peripheral neuropathy, which are well understood as contributing to gait instability and falls. A less understood complication of diabetes is the effect on the vestibular system. The vestibular system contributes significantly to balance in static and dynamic conditions by providing spatially orienting information. It is noteworthy that diabetes has been reported to affect vestibular function in both animal and clinical studies. Pathophysiological changes in peripheral and central vestibular structures due to diabetes have been noted. Vestibular dysfunction is associated with impaired balance and a higher risk of falls. As the prevalence of diabetes increases, so does the potential for falls due to diabetic complications. The purpose of this perspective article is to present evidence on the pathophysiology of diabetes-related complications and their influence on balance and falls, with specific attention to emerging evidence of vestibular dysfunction due to diabetes. Understanding this relationship may be useful for screening (by physical therapists) for possible vestibular dysfunction in people with diabetes and for further developing and testing the efficacy of interventions to reduce falls in this population.

Individualized Surgical Approach Planning for Petroclival Tumors Using a 3D Printer.

Objectivesu2003To determine the utility of three-dimensional (3D) printed models in individualized petroclival tumor resection planning by measuring the fidelity of printed anatomical structures and comparing tumor exposure afforded by different approaches. Designu2003Case series and review of the literature. Settingu2003Tertiary care center. Participantsu2003Three patients with petroclival lesions. Main Outcome Measuresu2003Subjective opinion of access by neuro-otologists and neurosurgeons as well as surface area of tumor exposure. Resultsu2003Surgeons found the 3D models of each patients skull and tumor useful for preoperative planning. Limitations of individual surgical approaches not identified through preoperative imaging were apparent after 3D models were evaluated. Significant variability in exposure was noted between models for similar or identical approaches. A notable drawback is that our printing process did not replicate mastoid air cells. Conclusionsu2003We found that 3D modeling is useful for individualized preoperative planning for approaching petroclival tumors. Our printing techniques did produce authentic replicas of the tumors in relation to bony structures.

Endoscopically Assisted Drilling, Exposure of the Fundus through a Presigmoid Retrolabyrinthine Approach: A Cadaveric Feasibility Study:

The presigmoid retrolabyrinthine approach to the cerebellopontine angle is traditionally described to not provide access to the internal auditory canal (IAC). We aimed to evaluate the extent of the IAC that could be exposed with endoscopically assisted drilling and to measure the percentage of the IAC that could be visualized with the microscope and various endoscopes after drilling had been completed. Presigmoid retrolabyrinthine approaches were performed bilaterally on 4 fresh cadaveric heads. We performed endoscopically assisted drilling to expose the fundus of the IAC, which resulted in exposure of the entire IAC in 8 of 8 temporal bone specimens. The microscope afforded a mean view of 83% (n = 8) of the IAC. The 0°, 30°, 45°, and 70° endoscope each afforded a view of 100% of the IAC in 8 of 8 temporal bone specimens. In conclusion, endoscopic drilling of the IAC of can provide an extradural means of exposing the entire length of the IAC while preserving the labyrinth.

Effect of Piecemeal vs En Bloc Approaches to the Lateral Temporal Bone on Survival Outcomes

Objectives Lateral temporal bone resection (LTBR) has traditionally been performed en bloc in accordance with oncologic principles. Occasionally, this is not possible due to a low tegmen or lateralized vasculature. We sought to determine if outcomes of piecemeal and en bloc LTBR are comparable. Study Design Retrospective review. Setting Two academic medical centers. Subjects and Methods Multi-institutional retrospective cohort study. Current Procedural Terminology codes were used to identify patients with T1 to T3 squamous cell carcinoma of the external auditory canal (EAC) who underwent LTBR from 2005 to 2015. Kaplan-Meier curves were constructed to compare total survival between the 2 treatment approaches. Pairwise comparisons were performed using χ2 and Fisher exact tests (significance at P = .05), as appropriate. Results Twenty-five patients were identified. Ten patients underwent en bloc LTBR; 15 underwent piecemeal LTBR. Median follow-up time was 11 months (range, 1-60 months). There was not a significant difference in overall survival between en bloc (38.9 months; 95% confidence interval [CI], 22.7-55.2) compared to piecemeal (37.5 months; 95% CI, 21.1-53.9) procedures (P = .519). Estimates of disease-free survival also did not reveal statistically significant differences: estimated mean disease-free survival was 48.1 months (95% CI, 33.7-62.6) in en bloc patients and 32.5 months (95% CI, 17.1-47.8) in piecemeal patients (P = .246). Conclusion These data suggest that piecemeal resection can be considered for cases of squamous cell carcinoma involving the external auditory canal where anatomic constraints preclude a safe en bloc resection. Larger studies or studies with a longer follow-up time may provide improved insight into survival comparisons.

Otolith Dysfunction in Persons With Both Diabetes and Benign Paroxysmal Positional Vertigo

OBJECTIVEnVestibular dysfunction is a well-recognized complication of type 2 diabetes (DM) that may contribute to increased fall risk. The prevalence of benign paroxysmal positional vertigo (BPPV) is higher in people with DM. The impact of DM on the otolith organs of the vestibular system in people with BPPV is unknown. The purpose of this study was to analyze otolith function using vestibular-evoked myogenic potential (VEMP) tests in people with DM and concurrent BPPV (BPPVu200a+u200aDM), and to examine the relationships between VEMP variables and diabetes-related variables.nnnSTUDY DESIGNnProspective, cross-sectional study.nnnSETTINGnTertiary academic medical center.nnnSUBJECTS AND METHODSnParticipants 40 to 65 years were recruited in four groups: controls (nu200a=u200a20), people with DM (nu200a=u200a19), BPPV (nu200a=u200a18), and BPPVu200a+u200aDM (nu200a=u200a14). Saccule and utricle function were examined using cervical VEMP (cVEMP) and ocular VEMP (oVEMP), respectively. Diabetes-related variables such as HbA1c, duration of diabetes, and presence of sensory impairment due to diabetes were collected.nnnRESULTSnThe frequency of abnormal cVEMP responses was higher in the DM (pu200a=u200a0.005), BPPV (pu200a=u200a0.003), and BPPVu200a+u200aDM (pu200a<0.001) groups compared with controls. In the participants with diabetes, higher HbA1c levels were correlated with prolonged P1 (pu200a=u200a0.03) and N1 latencies (pu200a=u200a0.03). The frequency of abnormal oVEMP responses was not different between groups (pu200a=u200a0.2).nnnCONCLUSIONnAlthough BPPV and DM may independently affect utricle and saccule function, they do not seem to have a distinct cumulative effect.

Impact of Resident Participation on Operative Time and Outcomes in Otologic Surgery

Objectives To describe the impact of resident involvement in tympanoplasty on operative time and surgical complication rates. Study Design Case series with chart review. Setting Tertiary medical center. Subjects and Methods Current Procedural Terminology codes were used to identify patients in the 2011-2014 public use files of the American College of Surgeons National Surgical Quality Improvement Program who underwent a tympanoplasty or tympanomastoidectomy. Cases were included if the database indicated whether the operating room was staffed with an attending alone or an attending with residents. Categorical and continuous variables were compared with chi-square, Fisher’s exact, and Mann-Whitney U tests. Generalized linear models with a log-link and gamma distribution were used to examine the factors affecting operative time. Results Overall, 1045 cases met our study criteria (tympanoplasty, n = 797; tympanomastoidectomy, n = 248). Resident involvement increased mean operative time for tympanoplasties by 46% (107 vs 73 minutes, P < .001) and tympanomastoidectomies by 49% (175 vs 117 minutes, P < .001). While controlling for confounding factors, the variable with the largest impact on operative time was resident involvement. There were no significant differences observed in the rate of surgical complications between attending-alone and attending-resident cases. Conclusion Resident involvement in tympanoplasty and tympanomastoidectomy did not affect the surgical complication rate. Resident involvement increased operative time for tympanoplasties and tympanomastoidectomies; however, the specific reasons for the increase are not explained by the available data.