Pre-habilitation Before Vestibular Schwannoma Surgery-Impact of Intratympanal Gentamicin Application on the Vestibulo-Ocular Reflex

Vestibular Prehabilitation-A Single UK Center Experience and Literature Review

Objectives  To assess whether vestibular prehabilitation with intratympanic gentamicin is a useful preoperative adjunct in allowing for early mobilization and short length of stay in patients with vestibular schwannoma (VS). Design  Retrospective single-center study and literature review. Setting  Tertiary neurosurgical center. Participants  Adult patients undergoing surgery for VS. Main Outcome Measures  Our primary outcome measures were evidence of compensation following prehabilitation (defined as saccades becoming more covert and clustered on video head impulse testing-vHIT), length of stay, and days until mobilization. Secondary outcome measures were reduction in gain on vHIT following treatment as well as need for antiemetics postoperatively. Results  Ten patients have been treated at our center and the majority have shown preoperative reduction in gain and evidence of compensation on vHIT. Median time to mobilization was 1 day and modal length of stay was 6 days. We found the current evidence to be variable, with small sample sizes and significant variation in outcome measures used. Conclusion  Overall we have found that the use of vestibular prehabilitation enables early mobilization, shortened length of stay and appears to be a promising preoperative adjunct in this population. Further research and assessment with a multicenter prospective clinical trial is merited.

The comparison between intratympanic gentamicin prehabilitation and postoperative virtual reality exposure to standard vestibular training in patients with vestibular schwannoma

OBJECTIVE

Resection of the vestibular schwannoma causes acute peripheral vestibular loss. The process of central compensation starts immediately afterward. The rehabilitation goal is to support this process and restore the quality of life.

MATERIALS AND METHODS

In this prospective single-center study, 67 consecutive patients underwent vestibular schwannoma resection (40 females, mean age 52 ± 12 years). The patients were divided into three groups: the prehabilitation with intratympanic gentamicin group, the virtual reality group (optokinetic stimulation via virtual reality goggles in the first ten days after the surgery), and the control group. All patients were examined with objective methods and completed questionnaires before the prehabilitation, before the surgery, at the hospital discharge, and after three months.

RESULTS

Intratympanic gentamicin prehabilitation leads ipsilaterally to a significant aVOR reduction in all semicircular canals (p < 0.050), the increase of the unilateral weakness in air calorics (p = 0.026), and loss of cVEMPs responses (p = 0.017). Prehabilitation and postoperative exposure to virtual reality scenes improved the patient's perception of vertigo problems according to Dizziness Handicap Inventory (p = 0.039 and p = 0.076, respectively). These findings conform with the optokinetic testing results, which showed higher slow phase velocities at higher speeds (40 deg/s) in both targeted groups compared to the control group.

CONCLUSION

Preoperative intratympanic gentamicin positively affects peripheral vestibular function, influencing balance perception after VS resection. In long-term follow-up, prehabilitation and postoperative exposure to virtual reality improve patients' quality of life in the field of vertigo problems.

Intraoperative ultrasonography in microsurgical resection of vestibular schwannomas via retrosigmoid approach: surgical technique and proof-of-concept illustrative case series

PURPOSE

Intraoperative ultrasonography (ioUS) is an established tool for the real-time intraoperative orientation and resection control in intra-axial oncological neurosurgery. Conversely, reports about its implementation in the resection of vestibular schwannomas (VS) are scarce. The aim of this study is to describe the role of ioUS in microsurgical resection of VS.

METHODS

ioUS (Craniotomy Transducer N13C5, BK5000, B Freq 8 MHz, BK Medical, Burlington, MA, USA) is integrated into the surgical workflow according to a 4-step protocol (transdural preresection, intradural debulking control, intradural resection control, transdural postclosure). Illustrative cases of patients undergoing VS resection through a retrosigmoid approach with the use of ioUS are showed to illustrate advantages and pitfalls of the technique.

RESULTS

ioUS allows clear transdural identification of the VS and its relationships with surgically relevant structures of the posterior fossa and of the cerebellopontine cistern prior to dural opening. Intradural ioUS reliably estimates the extent of tumor debulking, thereby helping in the choice of the right moment to start peripheral preparation and in the optimization of the extent of resection in those cases where subtotal resection is the ultimate goal of surgery. Transdural postclosure ioUS accurately depicts surgical situs.

CONCLUSION

ioUS is a cost-effective, safe, and easy-to-use intraoperative adjunctive tool that can provide a significant assistance during VS surgery. It can potentially improve patient safety and reduce complication rates. Its efficacy on clinical outcomes, operative time, and complication rate should be validated in further studies.

Pre-habilitation with intratympanic gentamicin in vestibular schwannomas: a systematic review

OBJECTIVE

To assess whether pre-habilitation with intratympanic gentamicin can accelerate vestibular compensation following vestibular schwannoma resection.

METHODS

Seventeen studies were retrieved from the databases Medline, PubMed, Frontiers, Cochrane Library, Cambridge Core and ScienceDirect. Eight of the 17 studies met our criteria; the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used. Heterogeneity, risk of bias and effect on post-operative recovery were assessed.

RESULTS

Four of the eight studies showed a statistically positive effect of pre-habilitation with gentamicin on the post-operative recovery process; the remainder also reported benefits, although not statistically significant. No study reported negative effects. Limitations were linked mostly to the limited number of enrolled patients and the outcome assessment methods.

CONCLUSION

Fifty per cent of the studies found a statistically positive effect of pre-habilitation with gentamicin prior to vestibular schwannoma resection. While the results are promising, due to the limited numbers further prospective studies are required to strengthen the evidence.

[Intratympanic Drug Application - Indication and Procedure]

Neurootologic disorders of the inner ear associated with symptoms such as tinnitus, vertigo, and hearing loss are common and often cause significant distress to affected patients. Treatment options are usually limited. There are now some indications for which intratympanic drug application is a possible treatment option. Intratympanic drug administration is a simple, inexpensive therapy option with few side effects that can be used on an outpatient basis. Therefore, it should not be disregarded when indicated.

Subjective perception of activity level: A prognostic factor for developing chronic dizziness after vestibular schwannoma resection?

Introduction

A vestibular schwannoma (VS) resection causes an acute unilateral vestibular deafferentation resulting in acute postoperative symptoms. Despite the expected resolution of most of the symptoms, due to central vestibular compensation, more than one out of four patients develop chronic dizziness. Several predictive factors, such as age and tumor size, have been suggested. Despite its potential effect on the process of central vestibular compensation, the level of physical activity after VS resection was not yet considered. Therefore, the association between the level of physical activity and chronic dizziness after VS resection will be investigated.

Methods

This retrospective cohort study included 66 patients who underwent a retro-sigmoid VS resection between October 2001 and February 2007. Patients were assessed before surgery and at 9 weeks and 6 months postoperatively. At 9 weeks, patients were asked to report their level of physical activity (PA) during the past week by using a visual analogue scale and their balance performance was assessed by four standing balance conditions with eyes closed and the Timed Up and Go test (TUG). Based on the Dizziness Handicap Inventory (DHI) score at 6 months, patients were divided in a chronic dizziness group (DHI > 30) and non-chronic dizziness group (DHI-score ≤ 30). Age, sex, Koos classification, preoperative vestibular function, treatment group, balance performance, and level of PA were compared between both groups and used as independent variables in linear regression analyses with the DHI score at 6 months as dependent variable.

Results

The chronic dizzy patients revealed to have significantly lower levels of PA (p < 0.001) and worse static and dynamic balance performance (p = 0.023 and p = 0.041, respectively) 9 weeks after surgery. After elimination, the multiple regression analysis resulted in a model with two variables (PA level, TUG) which significantly predicted the DHI score (F_2,42 = 6.581; R² = 0.239; p = 0.003).

Conclusion

This study revealed associations between (1) the level of PA and balance performance in the subacute phase and (2) chronic dizziness after VS resection. Assessment of the level of PA and balance performance during the subacute phase, which can be performed in a non-invasive and non-time-consuming way, might therefore provide prognostic information after VS resection.

[The application value of video head impulse test, caloric test and dizziness handicap inventory in the diagnosis of acoustic neuroma]

Objective:To explore the application value of video head impulse test（vHIT）, caloric test（CT） and the dizziness handicap inventory（DHI） in the diagnosis of acoustic neuroma（AN）, to analyze the correlation between vHIT and CT, and to determine the correlationsof tumor size, vHIT, CT and DHI score. Methods:The clinical data of 24 patients with AN who underwent surgery in our department from January 2019 to January 2022 were analyzed retrospectively, including craniocerebral MRI, vHIT, caloric test and DHI score. All the data were statistically analyzed by GraphPadPrism9.0. Results:There was a significant negative correlation between the UW value of CT and the vestibular eye reflex gain of vHIT（P<0.01, r=-0.62）. The tumor size was significantly correlated with the increase of UW value of CT（P<0.01, r=0.69）, and with the decrease of vestibulo-ocular reflex gain of vHIT（P<0.01, r=-0.53）. The average Dizziness Handicap Inventory score was 8.9±16.2, which was not correlated with tumor size（P>0.05）. Conclusion:Both vHIT and CT can effectively evaluate the vestibular function of patients with AN（and they are complementary）, and they are related to the size of the tumor and have certain value in the diagnosis of acoustic neuroma.

Vestibular function testing in the 21st century: video head impulse test, vestibular evoked myogenic potential, video nystagmography; which tests will provide answers?

PURPOSE OF REVIEW

To most neurologists, assessing the patient with vertigo is an unpleasant and worrisome task. A structured history and focused examination can be complemented by carefully selected laboratory tests, to reach an early and accurate diagnosis. We provide evidence-based recommendations for vestibular test selection.

RECENT FINDINGS

The video head impulse test (vHIT), cervical and ocular vestibular evoked myogenic potential (VEMP) and home-video nystagmography are four modern, noninvasive methods of assessing vestibular function, which are equally applicable in the hospital and office-practice. Collectively, they enable assessment of all five vestibular end-organs. The prevalence and patterns of test abnormalities are distinct for each vestibular disorder. We summarize typical abnormalities encountered in four common vestibular syndromes.

SUMMARY

In the context of acute vestibular syndrome, an abnormal vHIT with low gain and large amplitude refixation saccades and an asymmetric oVEMP separates innocuous vestibular neuritis from stroke. In episodic spontaneous vertigo, high-velocity ictal nystagmus and asymmetric cVEMP help separate Ménière's disease from vestibular migraine. In chronic imbalance, all three tests help detect unilateral or bilateral vestibular loss as the root cause. Recurrent positional vertigo requires no laboratory test and can be diagnosed and treated at the bedside, guided by video nystagmography.