Tumour resection volumes and facial nerve outcomes for vestibular schwannomas

Outcomes of Near-Total and Subtotal Resection of Sporadic Vestibular Schwannoma: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate tumor control and facial nerve outcomes after gross-total (GTR), near-total (NTR), and subtotal resection (STR) of sporadic vestibular schwannomas (VS).

DATA SOURCES

PubMed, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus databases were searched in August 2021 through inception following PRISMA guidelines.

REVIEW METHODS

English language articles reporting tumor control and facial nerve outcomes of adults (≥18 years) with NTR and STR of VS were evaluated. Study characteristics, demographics data, tumor characteristics, type of surgical intervention, and outcome measures on tumor control and facial nerve function were collected. Pooled relative risk (RR) estimates for tumor recurrence and facial nerve outcomes were calculated and stratified by extent of resection.

RESULTS

From an initial search of 2504 articles, 48 studies were included in the analysis. When comparing 1108 patients who underwent NTR to 3349 patients with GTR, the pooled RR of recurrence in the NTR cohort was 2.94 (95% confidence interval [CI] 1.65-5.24, P = .0002). When comparing 1016 patients who underwent STR to 6171 patients with GTR, the pooled RR of recurrence in the STR cohort was 11.50 (95% CI 6.64-19.92, P < .0001). Estimates for risk of tumor regrowth for less-than-complete resection are presented. There was no elevated risk of adverse facial nerve outcome (defined as House-Brackmann grade III and above) in each category of extent of resection compared to GTR.

CONCLUSION

Extent of resection predicts risk of tumor recurrence/regrowth following microsurgical resection. Favorable facial nerve outcome should be weighed against the increased risk of regrowth and the potential need for further treatment.

Quality of Life in Patients with Vestibular Schwannomas Following Gross Total or Less than Gross Total Microsurgical Resection: Should We be Taking the Entire Tumor Out?

BACKGROUND

The goal of microsurgical removal of a vestibular schwannoma is to completely remove the tumor, to provide long-term durable cure. In many cases, less than gross total resection (GTR) is performed to preserve neurological, and especially facial nerve function.

OBJECTIVE

To analyze long-term quality of life (QoL) in a cohort of patients who received either GTR or less than GTR.

METHODS

Patients operated for vestibular schwannoma less than 3.0 cm in posterior fossa diameter at 1 of 2 international tertiary care centers were surveyed using generic and disease-specific QoL instruments.

RESULTS

A total of 143 patients were analyzed. GTR was performed in 122, and 21 underwent less than GTR. QoL was assessed at a mean of 7.7 yr after surgery (interquartile range: 5.7-9.6). Patients who underwent GTR had smaller tumors; otherwise, there were no baseline differences between groups. Patients who underwent GTR, after multivariable adjustment for baseline features and facial nerve and hearing outcomes, reported statistically significantly better Short Form Health Survey-36 (SF-36) physical and mental scores, Patient-Reported Outcomes Measurement Information System (PROMIS-10) physical and mental scores, and Penn Acoustic Neuroma Quality of Life (PANQOL) facial, energy, general health, and total scores compared to patients receiving less than GTR.

CONCLUSION

GTR is associated with better QoL using the general QoL measures SF-36 and PROMIS-10 and the disease-specific PANQOL, even after controlling for baseline and outcome differences. This is especially significant in the assessment of mental health, indicating there may indeed be a psychological advantage to the patient that translates to overall well-being to have the entire tumor removed if microsurgical resection is undertaken.

Continuous dynamic mapping to avoid accidental injury of the facial nerve during surgery for large vestibular schwannomas

In vestibular schwannoma (VS) surgery postoperative facial nerve (CN VII) palsy is reducing quality of life. Recently, we have introduced a surgical suction device for continuous dynamic mapping to provide feedback during tumor resection without switching to a separate stimulation probe. The objective was to evaluate the reliability of this method to avoid CN VII injury. Continuous mapping for CN VII was performed in large VS (08/2014 to 11/2017) additionally to standard neurophysiological techniques. A surgical suction-and-mapping probe was used for surgical dissection and continuous monopolar stimulation. Stimulation was performed with 0.05-2 mA intensities (0.3 msec pulse duration, 2.0 Hz). Postoperative CNVII outcome was assessed by the House-Brackmann-Score (HBS) after 1 week and 3 months following surgery. Twenty patients with Koos III (n = 2; 10%) and Koos IV (n = 18; 90%) VS were included. Preoperative HBS was 1 in 19 patients and 2 in 1 patient. Dynamic mapping reliably indicated the facial nerve when resection was close to 5-10 mm. One week after surgery, 7 patients presented with worsening in HBS. At 3 months, 4 patients' facial weakness had resolved and 3 patients (15%) had an impairment of CN VII (HBS 3 and 4). Of the 3 patients, near-total removal was attempted in 2. The continuous dynamic mapping method using an electrified surgical suction device might be a valuable additional tool in surgery of large VS. It provides real-time feedback indicating the presence of the facial nerve within 5-10 mm depending on stimulation intensity and may help in avoiding accidental injury to the nerve.

Subtotal resection of vestibular schwannoma: Evaluation with Ki-67 measurement, magnetic resonance imaging, and long-term observation

Purpose

The aim of this study was to compare the postoperative clinical and radiological data of patients with vestibular schwannomas who were initially managed by near total resection (NTR) or subtotal resection (STR). The Ki-67 analysis results were compared with tumor regrowth to determine the presence of a correlation between this proliferative index and postoperative tumor regrowth.

Study Design

Seventeen adult patients (7 male, 10 female) were retrospectively reviewed. Nine (52.9%) and eight (47.1%) patients underwent NTR and STR, respectively. Postoperative clinical and radiological data associated with vestibular schwannoma growth were compared with the Ki-67 immunohistochemical analysis results.

Results

Evidence of clinically significant regrowth was observed in four (23.5%) patients. Patients who underwent NTR had a lower rate/incidence of tumor regrowth than did patients who underwent STR. Patients with a higher Ki-67 index had the highest tumor regrowth rates.

Conclusions

Our study indicates that assessment of the Ki-67 index may be useful for determining the probability of regrowth of vestibular schwannomas when only partial removal is accomplished.

Advanced Vestibular Schwannoma: A Case of Optic Disc Oedema without Hydrocephalus

A wide range of pathologies can cause papilloedema. Vestibular schwannoma is a benign and slow-growing tumour that causes symptoms and findings on ophthalmic examination when the diagnostic is delayed. The authors report a case of a 64-year-old male who presented with bilateral disc oedema secondary to a vestibular schwannoma grade 4. Obstructive hydrocephalus was not evident. The authors suggest that cerebrospinal fluid protein may have a role in the formation of optic disc oedema. A right suboccipital craniectomy was performed to remove the tumour, leading to secondary facial palsy.