Prophylactic nimodipine treatment for hearing preservation after vestibular schwannoma surgery: study protocol of a randomized multi-center phase III trial-AkniPro 2.

BACKGROUND: A previously performed phase III trial on 112 subjects investigating prophylactic nimodipine treatment in vestibular schwannoma (VS) surgery showed no clear beneficial effects on preservation of facial and cochlear nerve functions, though it should be considered that protection of facial nerve function was the primary outcome. However, the risk for postoperative hearing loss was halved in the nimodipine group compared to the control group (OR 0.49; 95% CI 0.18-1.30; p = 0.15). Accordingly, this phase III extension trial investigates the efficacy and safety of prophylactic nimodipine for hearing preservation in VS surgery. METHODS: This is a randomized, multi-center, two-armed, open-label phase III trial with blinded expert review and two-stage with interim analysis. Three hundred thirty-six adults with the indication for microsurgical removal of VS (Koos I-IV) and serviceable preoperative hearing (Gardner-Robertson scale (GR) 1-3) are assigned to either the therapy (intravenous nimodipine 1-2 mg/h from the day before surgery until the fifth postoperative day and standard of care) or the control group (surgery only and standard of care). The primary endpoint of the trial is postoperative cochlear nerve function measured before discharge according to GR 1-3 versus GR 4-5 (binary). Hearing function will be determined by pre- and postoperative audiometry with speech discrimination, which will be evaluated by a blinded expert reviewer. Furthermore, patient-reported outcomes using standardized questionnaires will be analyzed. DISCUSSION: Prophylactic parenteral nimodipine treatment may have a positive effect on hearing preservation in VS surgery and would improve patient's quality of life. Further secondary analyses are planned. Except for dose-depending hypotension, nimodipine is known as a safe drug. In the future, prophylactic nimodipine treatment may be recommended as a routine medication in VS surgery. VS can be considered as an ideal model for clinical evaluation of neuroprotection, since hearing outcome can be classified by well-recognized criteria. The beneficial effect of nimodipine may be transferable to other surgical procedures with nerves at risk and may have impact on basic research. TRIAL REGISTRATION: EudraCT 2019-002317-19, DRKS00019107 . 8th May 2020.

Prophylactic nimodipine treatment improves hearing outcome after vestibular schwannoma surgery in men: a subgroup analysis of a randomized multicenter phase III trial.

A 2016 published randomized multicenter phase III trial of prophylactic nimodipine treatment in vestibular schwannoma surgery showed only a tendency for higher hearing preservation rates in the treatment group. Gender was not included in statistical analysis at that time. A retrospective analysis of the trial considering gender, preoperative hearing, and nimodipine treatment was performed. The treatment group received parenteral nimodipine from the day before surgery until the seventh postoperative day. The control group was not treated prophylactically. Cochlear nerve function was determined by pure-tone audiometry with speech discrimination preoperatively, during in-patient care, and 1 year after surgery and classified according to the Gardner-Robertson grading scale (GR). Logistic regression analysis showed a statistically significant effect for higher hearing preservation rates (pre- and postoperative GR 1-4) in 40 men comparing the treatment (n = 21) and the control (n = 19) groups (p = 0.028), but not in 54 women comparing 27 women in both groups (p = 0.077). The results were also statistically significant for preservation of postoperative hearing with pre- and postoperative GR 1-3 (p = 0.024). There were no differences in tumor sizes between the treatment and the control groups in men, whereas statistically significant larger tumors were observed in the female treatment group compared with the female control group. Prophylactic nimodipine is safe, and an effect for hearing preservation in 40 men with preoperative hearing ability of GR 1-4 was shown in this retrospective investigation. The imbalance in tumor size with larger tumors in females of the treatment group may falsely suggest a gender-related effect. Further investigations are recommended to clarify whether gender has impact on nimodipine's efficacy.

Topical insulin in neurotrophic keratopathy after resection of acoustic neuroma. / Insulina tópica en queratopatía neurotrófica tras resección de neurinoma del acústico.

CASE REPORT: A patient with a history of surgical resection of an acoustic neuroma presented with involvement of both the left facial nerve and the left trigeminal nerve. She initially consulted for exposure keratitis, but two weeks later presented with an infectious keratitis. After taking the corneal sample, she presented with persistent epithelial defect, which did not respond to medical management. Topical insulin was indicated, and a decrease in the area of the lesion was seen in the following 5 days. A therapeutic contact lens was also placed at that time and finally, two weeks after the initiation of insulin, the epithelial defect completely closed. DISCUSSION: This was a complex case due to the confluence of facial paralysis, neurotrophic keratitis, and infectious keratitis, which finally had a successful outcome. Topical insulin can be an effective adjuvant therapy in cases of neurotrophic ulcers that do not respond to standard therapy.

Anti-tumor effects of cold atmospheric pressure plasma on vestibular schwannoma demonstrate its feasibility as an intra-operative adjuvant treatment.

Vestibular schwannoma (VS), although a benign intracranial tumor, causes morbidities by brainstem compression. Since chemotherapy is not very effective in most Nf2-negative schwannomas, surgical removal or radiation therapy is required. However, depending on the size and site of the tumor, these approaches may cause loss of auditory or vestibular functions, and severely decrease the post-surgical wellbeing. Here, we examined the feasibility of cold atmospheric pressure plasma (CAP) as an intra-operative adjuvant treatment for VS after surgery. Cell death was efficiently induced in both human HEI-193 and mouse SC4 VS cell lines upon exposure to CAP for seven minutes. Interestingly, both apoptosis and necroptosis were simultaneously induced by CAP treatment, and cell death was not completely inhibited by pan-caspase and receptor-interacting serine/threonine-protein kinase 1 (RIK1) inhibitors. Upon CAP exposure, cell death phenotype was similarly observed in patient-derived primary VS cells and tumor mass. In addition, CAP exposure after the surgical removal of primary tumor efficiently inhibited tumor recurrence in SC4-grafted mouse models. Collectively, these results strongly suggest that CAP should be developed as an efficient adjuvant treatment for VS after surgery to eliminate the possible remnant tumor cells, and to minimize the surgical area in the brain for post-surgical wellbeing.

Prophylactic nimodipine treatment and improvement in hearing outcome after vestibular schwannoma surgery: a combined analysis of a randomized, multicenter, Phase III trial and its pilot study.

OBJECTIVE In clinical routines, neuroprotective strategies in neurosurgical interventions are still missing. A pilot study (n = 30) and an analogously performed Phase III trial (n = 112) pointed to a beneficial effect of prophylactic nimodipine and hydroxyethyl starch (HES) in vestibular schwannoma (VS) surgery. Considering the small sample size, the data from both studies were pooled. METHODS The patients in both investigator-initiated studies were assigned to 2 groups. The treatment group (n = 70) received parenteral nimodipine (1-2 mg/hour) and HES (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 72) was not treated prophylactically. Facial and cochlear nerve functions were documented preoperatively, during the inpatient care, and 1 year after surgery. RESULTS Pooled raw data were analyzed retrospectively. Intent-to-treat analysis revealed a significantly lower risk for hearing loss (Class D) 12 months after surgery in the treatment group compared with the control group (OR 0.46, 95% CI 0.22-0.97; p = 0.04). After exclusion of patients with preoperative Class D hearing, this effect was more pronounced (OR 0.38, 95% CI 0.17-0.83; p = 0.016). Logistic regression analysis adjusted for tumor size showed a 4 times lower risk for hearing loss in the treatment group compared with the control group (OR 0.25, 95% CI 0.09-0.63; p = 0.003). Facial nerve function was not significantly improved with treatment. Apart from dose-dependent hypotension (p < 0.001), the study medication was well tolerated. CONCLUSIONS Prophylactic nimodipine is safe and may be recommended in VS surgery to preserve hearing. Prophylactic neuroprotective treatment in surgeries in which nerves are at risk seems to be a novel and promising concept. Clinical trial registration no.: DRKS 00000328 ( https://drks-neu.uniklinik-freiburg.de/drks_web/ ).

Towards an optimal paradigm for intraoperative auditory nerve monitoring with auditory steady state responses.

Auditory steady state responses (ASSR) may offer an alternative to brainstem auditory evoked potentials for monitoring of the auditory nerve during surgical procedures. In the current study, we evaluated the influence of noise on ASSR characteristics in total intravenous anesthesia (TIVA). Simulated ASSR in real noise recorded during surgery under TIVA were constructed with known parameters. Influence of amplitude, modulation frequency, averaging sweeps and detection threshold on ASSR were evaluated. High amplitude, more sweeps and a liberal threshold facilitated detection. High amplitude ASSR (80 nV) were detected in up to 45 % with 16 s of data, in 80-90 % with 112 s. Near-threshold ASSR were detected in 0.8-25 %. False positives ranged between 0.3 and 10.3 %. Number of sweeps did not influence false positives. Amplitude errors varied between -61 and +39 % and improved with more averages but not with different thresholds. Modulation rate demonstrated the strongest influence on all parameters. 110 Hz yielded best, 90 Hz the worst results. Choice of parameters strongly influences detection and characteristics of ASSR. Optimal parameters enabled detection after 16 s in 45 %. Due to specific noise characteristics, modulation has a critical impact, which is currently not sufficiently recognized in ASSR studies.

Auditory Monitoring in Vestibular Schwannoma Surgery: Intraoperative Development and Outcome.

OBJECTIVE: The auditory brainstem response (ABR) may be a predictor of postoperative cochlear nerve function. In this study, the course of intraoperative ABR monitoring was analyzed to find predictive markers for postoperative hearing function. PATIENTS AND METHODS: From 2010 to 2012, 46 patients who had had vestibular schwannoma surgery were investigated by intraoperative ABR monitoring. The type of ABR development was identified: type A, improved or stable ABR; type B, fluctuating or deteriorated ABR; and type C, slow or sudden ABR loss. Hearing function was correlated with ABR monitoring. RESULTS: The different types of ABR development showed a strong correlation with postoperative hearing (P < 0.001). ABR quality after 60% tumor removal was independently significant for hearing outcome. Possible interpretations are: 1) Independent of positive factors at the start of surgery at the final phase of tumor resection, what mattered for hearing outcome was the ABR quality (P < 0.001). 2) Dependence on ABR quality in the last phase might be a result of what the cochlear nerve has endured during resection. 3) The importance of ABR quality in the last phase might be because the tumor capsule is dissected from the nerves in that final phase. ANALYSIS: of critical actions with incidence of ABR impairment showed that dissection in the internal auditory canal and drilling were most critical. CONCLUSIONS: Intraoperative ABR development is a predictive factor for postoperative hearing outcome. Deterioration should be avoided, because ABR improvement as a result of good status at the beginning of surgery could not be assumed.

Prophylactic nimodipine treatment for cochlear and facial nerve preservation after vestibular schwannoma surgery: a randomized multicenter Phase III trial.

OBJECTIVE: A pilot study of prophylactic nimodipine and hydroxyethyl starch treatment showed a beneficial effect on facial and cochlear nerve preservation following vestibular schwannoma (VS) surgery. A prospective Phase III trial was undertaken to confirm these results. METHODS: An open-label, 2-arm, randomized parallel group and multicenter Phase III trial with blinded expert review was performed and included 112 patients who underwent VS surgery between January 2010 and February 2013 at 7 departments of neurosurgery to investigate the efficacy and safety of the prophylaxis. The surgery was performed after the patients were randomly assigned to one of 2 groups using online randomization. The treatment group (n = 56) received parenteral nimodipine (1-2 mg/hr) and hydroxyethyl starch (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 56) was not treated prophylactically. RESULTS: Intent-to-treat analysis showed no statistically significant effects of the treatment on either preservation of facial nerve function (35 [67.3%] of 52 [treatment group] compared with 34 [72.3%] of 47 [control group]) (p = 0.745) or hearing preservation (11 [23.4%] of 47 [treatment group] compared with 15 [31.2%] of 48 [control group]) (p = 0.530) 12 months after surgery. Since tumor sizes were significantly larger in the treatment group than in the control group, logistic regression analysis was required. The risk for deterioration of facial nerve function was adjusted nearly the same in both groups (OR 1.07 [95% CI 0.34-3.43], p = 0.91). In contrast, the risk for postoperative hearing loss was adjusted 2 times lower in the treatment group compared with the control group (OR 0.49 [95% CI 0.18-1.30], p = 0.15). Apart from dose-dependent hypotension (p < 0.001), no clinically relevant adverse reactions were observed. CONCLUSIONS: There were no statistically significant effects of the treatment. Despite the width of the confidence intervals, the odds ratios may suggest but do not prove a clinically relevant effect of the safe study medication on the preservation of cochlear nerve function after VS surgery. Further study is needed before prophylactic nimodipine can be recommended in VS surgery.

CE-Chirp® ABR in cerebellopontine angle surgery neuromonitoring: technical assessment in four cases.

Continuous monitoring of wave V of auditory brainstem response (ABR), also called brainstem auditory evoked potential (BAEP), is the most common method used in intraoperative neuromonitoring (IONM) functionality of cochlear nerve during surgery in cerebellopontine angle (CPA). CE-Chirp® ABR represents a recent development of classical ABR. CE-Chirp® is a new acoustic stimulus used in newborn hearing testing, designed to provide enhanced neural synchronicity and faster detection of larger amplitude wave V. In four cases, CE-Chirp® ABR was performed during cerebellopontine angle (CPA) surgery. CE-Chirp® ABR represented a safe and effective method in neuromonitoring functionality of vestibulocochlear nerve. A faster neuromonitoring feedback to surgical equipe was possible with CE-Chirp ABR®.

Neuroprotective efficacy of prophylactic enteral and parenteral nimodipine treatment in vestibular schwannoma surgery: a comparative study.

UNLABELLED: BACKGROUND AND STUDY AIMS/OBJECT: Oral nimodipine improves neurologic outcome after aneurysmal subarachnoid hemorrhage. In addition, the neuroprotective efficacy of nimodipine has been revealed following skull base, laryngeal, and maxillofacial surgery. Pharmacokinetic investigations showed nimodipine to reach higher serum levels following parenteral versus enteral administration. Furthermore, a correlation between nimodipine levels in serum, cerebrospinal fluid, and nerve tissue could be quantified. These observations raise the question whether the proven neuroprotective effect of nimodipine is related to its serum level. PATIENTS/MATERIAL AND METHODS: A consecutive series of 37 patients with vestibular schwannoma treated with nimodipine from the day before surgery until the seventh postoperative day was analyzed retrospectively. Both groups received standard dosages for enteral (n = 17) and parenteral (n = 20) nimodipine medication. Nimodipine levels were measured in pre- and postoperative serum and cerebrospinal fluid samples. Cochlear and facial nerve functions were documented before surgery, in the early postoperative course, and 1 year after surgery. RESULTS: Facial nerve outcome was significantly better in the group with parenteral nimodipine medication (p = 0.038). Logistical regression analysis revealed a seven times smaller risk for a deterioration of facial nerve function in the group with parenteral treatment. There was no difference in hearing preservation between both groups despite tumor size tending to be larger in the parenteral group. Intraoperative (p = 0.004), postoperative (p = 0.001), and serum and cerebrospinal fluid (p = 0.024) nimodipine levels were significantly higher following parenteral administration as compared with enteral administration. Both groups were comparable regarding tumor size and extent of resection. CONCLUSIONS: These results support a dependency of nimodipine's neuroprotective efficacy on its serum levels. Parenteral nimodipine treatment produces higher serum levels and has a higher neuroprotective potency in vestibular schwannoma surgery compared with enteral treatment.

Hearing thresholds and FMRI of auditory cortex following eighth cranial nerve surgery.

OBJECTIVE: Determine whether auditory cortex (AC) organization changed following eighth cranial nerve surgery in adults with vestibular-cochlear nerve pathologies. We examined whether hearing thresholds before and after surgery correlated with increased ipsilateral activation of AC from the intact ear. STUDY DESIGN: During magnetic resonance imaging sessions before and 3 and 6 months after surgery, subjects listened with the intact ear to noise-like random spectrogram sounds. SETTING: Departments of Radiology and Otolaryngology of Washington University School of Medicine. SUBJECTS AND METHODS: Three patients with acoustic neuromas received Gamma Knife radiosurgery (GK); 1 patient with Meniere's disease and 5 with acoustic neuromas had surgical resections (SR); 2 of the latter also had GK. Hearing thresholds in each ear were for pure tone stimuli from 250 to 8000 Hz before and after surgery (3 and 6 months). At the same intervals, we imaged blood oxygen level-dependent responses to auditory stimulation of the intact ear using an interrupted single-event design. RESULTS: Hearing thresholds in 2 of 3 individuals treated with GK did not change. Five of 6 individuals became unilaterally deaf after SRs. Ipsilateral AC activity was present before surgery in 6 of 9 individuals with ipsilateral spatial extents greater than contralateral in 3 of 9. Greater contralateral predominance was significant especially in left compared to right ear affected individuals, including those treated by GK. CONCLUSION: Lateralization of auditory-evoked responses in AC did not change significantly after surgery possibly due to preexisting sensory loss before surgery, indicating that less than profound loss may prompt cortical reorganization.

[Gamma knife radiosurgery]. / La radiochirurgie par Gamma Knife.

Gamma Knife radiosurgery can be used as an alternative or complementary therapy to neurosurgery or radiotherapy for the treatment of some brain disorders or tumors of small volume. The most frequent indications are brain metastases, vestibular schwannomas, meningiomas, trigeminal neuralgia, arteriovenous malformations, some gliomas, and pituitary adenomas. Created in 1999, the Gamma Knife Center of the ULB remains currently the unique center in Belgium where a Gamma Knife radiosurgery treatment can be performed.

Prophylactic intravenous nimodipine treatment in skull base surgery: pharmacokinetic aspects.

BACKGROUND: Nimodipine is primarily used in subarachnoid hemorrhage (SAH). Clinical trials revealed also a beneficial effect of prophylactic nimodipine treatment on cranial nerve functions following vestibular schwannoma surgery. OBJECTIVE: The unknown pharmacokinetics of prophylactically administered nimodipine were investigated. METHODS: Samples were taken from 27 patients with skull base lesions. Prophylactic intravenous nimodipine infusion was started 5.8-25.8 h (mean 17.9 h) before surgery. Nimodipine concentrations were determined in serum (intra- and postoperatively), cerebrospinal fluid (CSF) (intraoperatively), and tissue samples. RESULTS: Wide interindividual differences were observed. Mean concentrations for nimodipine were 46.9 ng/ml (SD: 6.4; min. 4.1 and max. 92.7 ng/ml) in intraoperative serum, 73.2 ng/ml (SD: 16.7; min. 6.6 and max. 253 ng/ml) in postoperative serum and 8.3 ng/ml (SD: 1.5; min. 1.0 und max. 29.7 ng/ml) in intraoperative CSF. The correlation between intra- and postoperative serum (p=0.004, r=0.560) and between intra-operative serum and CSF concentration (p=0.003, r=0.567) were statistically significant. Furthermore the correlation between intraoperative serum concentration and concentrations collected from vestibular nerves was high (r=0.711), but not statistically significant (p=0.178). CONCLUSIONS: Interindividually, continously administered intravenous nimodipine produces considerably variable serum levels. Controls of nimodipine serum concentrations may be useful to optimize nimodipine medication in skull base surgery and in the management of SAH. The serum nimodipine level is a useful marker for CSF and intracranial nerve tissue concentrations of nimodipine.

Contralateral hearing disturbance following posterior fossa surgery.

A 53-year-old man suffered contralateral hearing disturbance one day after acoustic neuroma surgery. Hearing function gradually recovered after steroid and hyperbaric therapy. Contralateral hearing disturbance after acoustic neuroma surgery is an extremely rare complication that can also occur after other posterior fossa surgery. The mechanism of this rare phenomenon remains unclear, but the patent cochlear aqueduct may be involved.

Tinnitus loudness in quiet and noise after resection of vestibular schwannoma.

OBJECTIVES: (1) To use a loudness model to assess the influence of loudness recruitment on estimates of the loudness of tinnitus obtained by loudness matching; (2) To compare the effect of background noise on the loudness of tinnitus for individuals who are unilaterally deaf after resection of vestibular schwannoma (VS) and those with idiopathic tinnitus. BACKGROUND: After translabyrinthine resection of VS, patients experience unilateral deafness and tinnitus in the operated ear. Most complain that their tinnitus is more bothersome in noisy environments, unlike those with idiopathic tinnitus. PARTICIPANTS: Unilaterally deaf individuals experiencing tinnitus as a consequence of VS surgery and a comparison group with idiopathic tinnitus. METHODS: Participants adjusted the level of a probe tone at the frequency where their hearing was best to match the loudness of their tinnitus in quiet; for VS participants, matches were made using a probe in the unaffected ear. Matches were then obtained in the presence of threshold-equalizing noise. RESULTS: For those with idiopathic tinnitus, the probe loudness level, calculated using a loudness model, was almost invariant with hearing loss at the probe frequency and was usually between 20 and 50 phons. For the VS group, the probe loudness level ranged from 6 to 51 phons. With increasing threshold-equalizing-noise level, the loudness match decreased slightly for the comparison group but increased significantly for the VS group. CONCLUSION: The tinnitus in quiet had a moderate loudness for both groups. Background noise slightly decreased tinnitus loudness for most participants with idiopathic tinnitus but increased tinnitus loudness for VS participants. We propose 2 possible mechanisms for the effect of noise in the VS group.

Inter-aural attenuation with insert earphones.

The aim of the present study was to determine inter-aural attenuation (IA) values for pure tones and a broadband click obtained using an ER-3A insert earphone with a foam plug and with a customized hard acrylic earmould. Participants were 15 adults with a longstanding unilateral dead ear. IA was operationally defined as the difference between the good-ear and poorer-ear not-masked air conduction threshold. Minimum IA values for the foam earplug were 50 dB and 55 dB for pure tones and broadband click, respectively. Minimum IA values for the hard acrylic earmould were 45 dB and 50 dB for pure tones and broadband click, respectively.

[Simultaneous injection of lidocaine improves predictability of effect of botulinum toxin]. / Simultane Injektion mit Lidocain verbessert die Vorhersehbarkeit des Effekts von Botulinumtoxin.

Injection of botulinum toxin A is a common procedure in Otorhinolaryngology, Ophtalmology and Neurolgy. Recently botulinum toxin treatment has been described to improve woundhealing after facial injuries. The lack of immediate predictibility of the ensuing paralytic effect is one of the daily challenges of botulinum toxin injections. In the present report we describe the simultaneous injection of botulinum toxin and lidocaine with the purpose to gain immediate feed back of the treatment effect. Furthermore we recommend the addition of adrenalin to reduce possible systemical toxin circulation.

Intraoperative brainstem auditory evoked potential pattern and perioperative vasoactive treatment for hearing preservation in vestibular schwannoma surgery.

OBJECTIVE: In vestibular schwannoma surgery, four different intraoperative brainstem auditory evoked potential (BAEP) patterns (stable BAEP, abrupt loss, irreversible progressive loss, reversible loss) can be identified and correlated with postoperative hearing outcome. Patients with reversible loss significantly benefit from postoperative vasoactive treatment consisting of hydroxyethyl starch and nimodipine. The present study investigates the treatment effect in the remaining three BAEP patterns. METHODS: A retrospective analysis was performed in 92 patients operated on for vestibular schwannoma between 1997 and 2005. Between 1997 and 2001, only patients with reversible loss of BAEP received vasoactive medication. Subsequently, all patients operated on between 2001 and 2005 received a 10 day course of therapy, regardless of the BAEP pattern. Serial audiological examinations before, after surgery and after 1 year were performed in all patients. RESULTS: All 30 patients with reversible loss of BAEP received medication, and postoperative hearing preservation was documented in 21 patients. All 13 patients with stable waves showed hearing preservation, regardless of treatment. In all 24 patients with abrupt loss and in all 25 patients with irreversible progressive loss, postoperative anacusis was documented, regardless of treatment. CONCLUSION: In patients with reversible loss of BAEP, a disturbed microcirculation of the cochlear nerve seems to be the underlying pathophysiological factor. In patients with abrupt or irreversible progressive loss, additional mechanical injury of nerve fibres determines hearing outcome. The study provides evidence that for the purpose of hearing preservation, only patients with reversible loss of BAEP benefit from vasoactive treatment.

Preoperative postural control of patients with vestibular schwannoma assessed by visual feedback posturography.

BACKGROUND: The need for an objective method to describe the functional postural control of patients with vestibular schwannoma in agreement with their subjective sensation of balance. OBJECTIVES: The objective was to compare the postural control of 49 patients with unilateral vestibular schwannoma (VS) with that of healthy subjects by using visual feedback posturography (VFP). We aimed to find out if preoperative postural control of the patients correlates with their subjective sensation of balance. METHODS: In the VFP, while standing on the platform, patients were instructed to move their center of gravity (COG) marker to the targets as fast and accurately as possible. Hit delay (HD) to the targets, hold percentage (HP) within the targets, COG marker velocity (CMV) to the targets, and balance index (BI) were calculated. We rated intensity of balance disturbance using a 5-point qualitative scale. RESULTS: Twenty-two (45%) patients had at least one abnormal VFP parameter, and 49% of patients were simultaneously symptomatic. Mean hit delay (HD), hold percentage (HP), and balance index (BI) were significantly worsened in patients with VS (p < 0.05). Increased HD and BI correlated significantly with subjective sensation of imbalance (p = 0.02). CONCLUSIONS: The overall deficit in preoperative postural control of the VS patients was not severe, and this finding agreed well with their subjective sensations.