Analysis of the results obtained in 120 patients with large acoustic neuromas surgically treated via the translabyrinthine-transtentorial approach

Meningitis after elective intracranial surgery: a systematic review and meta-analysis of prevalence

Meningitis is a potential complication of elective intracranial surgery (EIS). The prevalence of meningitis after EIS varies greatly in the literature. The objective of this study was to estimate the overall pooled prevalence of meningitis following EIS. Four databases (PubMed, Scopus, Web of Science, and Embase) were searched to identify relevant studies. Meta-analyses of proportions were used to combine data. Cochran's Q and I2 statistics were used to assess and quantify heterogeneity. Additionally, several subgroup analyses were conducted to investigate the source of heterogeneity and examine differences in the prevalence based on variables such as geographical regions, income level, and meningitis type. The meta-analysis included 83 studies (30 959 patients) from 26 countries. The overall pooled prevalence of meningitis after EIS was 1.6% (95% CI 1.1-2.1), with high heterogeneity present (I2 = 88%). The pooled prevalence in low- to middle-income countries and high-income countries was 2.7% (95% CI 1.6-4.1) and 1.2% (95% CI 0.8-1.7), respectively. Studies that reported only aseptic meningitis had a pooled prevalence of 3.2% (95% CI 1.3-5.8). The pooled prevalence was 2.8% (95% CI 1.5-4.5) in studies that reported only bacterial meningitis. Similar prevalence rates of meningitis were observed in the subgroups of tumor resection, microvascular decompression, and aneurysm clipping. Meningitis is a rare but not exceptional complication following EIS, with an estimated prevalence of 1.6%.

Surgical Outcomes After Total or Subtotal Resection of Large Vestibular Schwannoma: A Single-Institution Experience

BACKGROUND

Patients with large vestibular schwannomas have various surgical outcomes. The aim of this study is to evaluate facial nerve outcome and surgical complications in patients who underwent total and subtotal resection.

METHODS

Between October 2008 and September 2020, 72 patients underwent surgery in Rajavithi Hospital. Of these, 48 had total or subtotal resection. We classified these participants into two groups: VS ≥3 cm (Group A, n=30); and VS <3 cm (Group B, n=18). Both groups were compared in terms of clinical presentation, imaging data, facial nerve outcomes, and surgical complications. The retrosigmoid approach was used in each case, and all patients had follow-up for at least 1 year. Chi-square and Fisher's exact test were used for statistical analysis.

RESULTS

The mean tumor size in Group A was 3.8 cm compared with 1.5 cm in Group B. In Group A, clinical signs of hearing dysfunction, gait ataxia, and facial paresthesia were present in 96.7%, 66.7%, 50% of patients respectively, compared with 100%, 5.6%, and 11.1% respectively in Group B. Radiographic signs of hydrocephalus were observed in 56.7% of Group A subjects, and 5.6% of those in Group B. At 1 year follow-up, 40% of patients with large VS and 94.4% of patients with small to medium size VS had good facial nerve outcomes (House-Brackmann [HB] facial grading scale grade I-III). Significant differences between the two groups were found only in gait ataxia (p<0.001), facial paresthesia (p=0.006), radiographic signs of hydrocephalus (p=0.002), facial nerve outcome 1 month (p<0.001) and facial nerve outcome 1 year (p<0.001).

CONCLUSION

In patients with large size VS, microsurgical resection had poor facial nerve outcomes compared with those of their counterparts with small to medium size VS. Planned subtotal resection with postoperative radiosurgery might attain superior facial nerve outcomes and result in better quality of life in subjects with large VS.

Treatment for vestibular schwannoma: Systematic review and single arm meta-analysis

OBJECTIVE

Vestibular schwannoma is a benign tumor in the schwannoma cells of the 8th cranial nerve. It causes symptoms like tinnitus, vertigo and end up with loss of hearing so the appropriate treatment is very important. There are many treatment techniques including conservative, surgery and radiosurgery. We aimed to systematically review and single arm meta-analysis the different treatment techniques of vestibular schwannoma.

METHODS

A comprehensive literature search using thirteen databases including PubMed, Scopus, and Web of Science was performed. All clinical trials about treatment vestibular schwannoma were included and single arm meta-analyzed. We assessed the risk of bias using ROBIN-I's tool and scale of Council Australia's Cancer Guidelines Wiki. The protocol was registered in PROSPERO (CRD42018089784) and has been updated on 17 April 2019.

RESULTS

A total of 35 clinical trials studies were included in the final analysis. The pooled proportion of stable hearing capability in patients receiving gamma knife radiosurgery (GKRS) was 64% (95% CI: 52%-74%). GKRS favored increased hearing capability 10% (95% CI: 7%-16%). Regarding tumor size, GKRS is the most protective method 53% (95% CI: 37%-69%). Complications occurred most commonly in single fractional linac stereotactic radiosurgery (SFSRT) 37% (95% CI: 12%-72%).

CONCLUSION

Our analysis suggested gamma knife radiosurgery could be the most ideal treatment for vestibular schwannoma based on stabilizing hearing capability, increasing hearing capability, decreasing tumor size and complications.

Comparison of Cranioplasty Techniques Following Translabyrinthine Surgery: Implications for Postoperative Pain and Opioid Usage

OBJECTIVE

To assess differences in postoperative pain, opioid usage, and surgical outcomes between cranioplasty using abdominal fat graft (AFG) versus hydroxyapatite cement (HAC) following translabyrinthine surgery.

STUDY DESIGN

Retrospective case control.

SETTING

Tertiary referral center.

PATIENTS

Sixty translabyrinthine procedures were evaluated, including 30 consecutive HAC patients and 30 matched AFG patients. Patients were matched by age, gender, body mass index, and tumor size.

INTERVENTION

Cranioplasty using HAC or AFG following translabyrinthine resection of vestibular schwannoma.

MAIN OUTCOME MEASURES

Postoperative patient pain ratings, narcotic usage, inpatient length of stay, and complication rates.

RESULTS

Patients who underwent HAC cranioplasty had lower postoperative pain scores on several measures (p < 0.05) and less postoperative narcotic usage (mean difference of 36.7 morphine equivalents, p = 0.0025) when compared to those that underwent AFG closure. HAC cranioplasty patients had shorter average length of hospital stay (2.2 vs 3.4 days, p = 0.0441). Postoperative cerebrospinal fluid leaks (one in HAC group, two in AFG group) and skin reactions in AFG closure patients (n = 1) were infrequent.

CONCLUSION

HAC cranioplasty is a safe technique comparable to AFG closure following translabyrinthine surgery which can decrease postoperative pain, narcotic usage, and hospital length of stay.

The incidence of postoperative cerebrospinal fluid leakage after elective cranial surgery: a systematic review

Cerebrospinal fluid (CSF) leakage is a major complication after elective neurosurgical procedures. The aim of this systematic literature review is to summarize the incidence rates of postoperative cerebrospinal fluid leakage for neurosurgical procedures, classified by surgical approach. The Pubmed, Cochrane, Embase, and Web of Science databases were searched for studies reporting the outcome of patients undergoing elective neurosurgical procedures. The number of patients, surgical approach, and indication for surgery were recorded for each study. Outcomes related to CSF leakage such as clinical manifestation and treatment were reported as well. One hundred and thirteen studies were included, reporting 94,695 cases. Overall, CSF leaks were present in 3.8% of cases. Skull base surgery had the highest rate of CSF leakage with 6.2%. CSF leakage occurred in 5.9% of anterior skull base procedures, 6.4% of middle fossa, and 5.2% of transpetrosal surgeries. 5.8% of reported infratentorial procedures were complicated by CSF leakage versus 2.9% of supratentorial surgeries. CSF leakage remains a common serious adverse event after cranial surgery. There exists a need for standardized procedures to reduce the incidence of postoperative CSF leakage, as this serious adverse event may lead to increased health care costs.

Impact of extent of internal acoustic meatus tumor removal using translabyrinthine approach for acoustic neuroma surgery

Objectives

Many studies have investigated the surgical outcome and predictive factors of acoustic neuroma using different approaches. The present study focused on large tumors due to the greater likelihood of internal acoustic meatus involvement and the greater application of surgical intervention than radiosurgery. There have been no previous reports on outcomes of internal acoustic meatus tumor removal. We investigated the impact of the extent of internal acoustic meatus tumor removal using a translabyrinthine approach for large acoustic neuroma surgery and predictive factors of tumor control.

Methods

This retrospective study reviewed 104 patients with large cerebellopontine angle tumor >3 cm treated by translabyrinthine approach microsurgery. Predictive factors of postoperative facial palsy, tumor control, and extent of internal acoustic meatus tumor removal were assessed.

Results

The mean tumor size was 38.95 ± 6.83 mm. Postoperative facial function showed 76.9% acceptable function (House–Brackmann grade 1 or 2) six months after surgery. The extent of internal acoustic meatus tumor removal was a statistically significant predictor factor of poor postoperative facial function. Younger age, larger tumor size needing radiosurgery, and more extensive removal of tumor were associated with better tumor control.

Conclusion

More extensive internal acoustic meatus tumor removal was associated with poor postoperative facial function and better tumor control.

Clinical Studies and Pre-clinical Animal Models on Facial Nerve Preservation, Reconstruction, and Regeneration Following Cerebellopontine Angle Tumor Surgery-A Systematic Review and Future Perspectives

Background and purpose: Tumorous lesions developing in the cerebellopontine angle (CPA) get into close contact with the 1st (cisternal) and 2nd (meatal) intra-arachnoidal portion of the facial nerve (FN). When surgical damage occurs, commonly known reconstruction strategies are often associated with poor functional recovery. This article aims to provide a systematic overview for translational research by establishing the current evidence on available clinical studies and experimental models reporting on intracranial FN injury.

Methods: A systematic literature search of several databases (PubMed, EMBASE, Medline) was performed prior to July 2020. Suitable articles were selected based on predefined eligibility criteria following the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Included clinical studies were reviewed and categorized according to the pathology and surgical resection strategy, and experimental studies according to the animal. For anatomical study purposes, perfusion-fixed adult New Zealand white rabbits were used for radiological high-resolution imaging and anatomical dissection of the CPA and periotic skull base.

Results: One hundred forty four out of 166 included publications were clinical studies reporting on FN outcomes after CPA-tumor surgery in 19,136 patients. During CPA-tumor surgery, the specific vulnerability of the intracranial FN to stretching and compression more likely leads to neurapraxia or axonotmesis than neurotmesis. Severe FN palsy was reported in 7 to 15 % after vestibular schwannoma surgery, and 6% following the resection of CPA-meningioma. Twenty-two papers reported on experimental studies, out of which only 6 specifically used intracranial FN injury in a rodent (n = 4) or non-rodent model (n = 2). Rats and rabbits offer a feasible model for manipulation of the FN in the CPA, the latter was further confirmed in our study covering the radiological and anatomical analysis of perfusion fixed periotic bones.

Conclusion: The particular anatomical and physiological features of the intracranial FN warrant a distinguishment of experimental models for intracranial FN injuries. New Zealand White rabbits might be a very cost-effective and valuable option to test new experimental approaches for intracranial FN regeneration. Flexible and bioactive biomaterials, commonly used in skull base surgery, endowed with trophic and topographical functions, should address the specific needs of intracranial FN injuries.

Effect of subdural muscle packing in repairing dura mater after retrosigmoid craniotomy

Objective

This study was performed to evaluate a new type of autologous muscle tamponade to repair dura mater that has undergone dural defects to prevent cerebrospinal fluid leakage or subcutaneous fluid accumulation.

Methods

Three hundred thirty-two patients who underwent retrosigmoid craniotomy were selected and divided into two groups: bone window craniotomy and bone flap craniotomy. Each group was further divided into two groups: artificial dura repair and autologous muscle repair. We then analysed the incidence of postoperative cerebrospinal fluid leakage or subcutaneous fluid accumulation and compared the effects of the two repair methods.

Results

For all patients, autologous muscle repair of the dura mater had a lower incidence of cerebrospinal fluid leakage than artificial dura mater repair, especially in patients with craniotomy.

Conclusions

Subdural craniotomy of the bone window is more effective than conventional methods in preventing cerebrospinal fluid leakage.

Surgical management for large vestibular schwannomas: a systematic review, meta-analysis, and consensus statement on behalf of the EANS skull base section

BACKGROUND AND OBJECTIVE

The optimal management of large vestibular schwannomas continues to be debated. We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of this problem from a European perspective.

MATERIAL AND METHODS

A systematic review of MEDLINE database, in compliance with the PRISMA guidelines, was performed. A subgroup analysis screening all surgical series published within the last 20 years (January 2000 to March 2020) was performed. Weighted summary rates for tumor resection, oncological control, and facial nerve preservation were determined using meta-analysis models. This data along with contemporary practice patterns were discussed within the task force to generate consensual recommendations regarding preoperative evaluations, optimal surgical strategy, and follow-up management.

RESULTS

Tumor classification grades should be systematically used in the perioperative management of patients, with large vestibular schwannomas (VS) defined as > 30 mm in the largest extrameatal diameter. Grading scales for pre- and postoperative hearing (AAO-HNS or GR) and facial nerve function (HB) are to be used for reporting functional outcome. There is a lack of consensus to support the superiority of any surgical strategy with respect to extent of resection and use of adjuvant radiosurgery. Intraoperative neuromonitoring needs to be routinely used to preserve neural function. Recommendations for postoperative clinico-radiological evaluations have been elucidated based on the surgical strategy employed.

CONCLUSION

The main goal of management of large vestibular schwannomas should focus on maintaining/improving quality of life (QoL), making every attempt at facial/cochlear nerve functional preservation while ensuring optimal oncological control, thereby allowing to meet patient expectations. Despite the fact that this analysis yielded only a few Class B evidences and mostly expert opinions, it will guide practitioners to manage these patients and form the basis for future clinical trials.

Facial Nerve Outcomes Following Total Excision of Vestibular Schwannoma by the Enlarged Translabyrinthine Approach

OBJECTIVE

To study the early and late facial nerve (FN) outcomes in different tumor classes in addition to determining the predictive factors for the same.

STUDY DESIGN

A retrospective clinical study.

SETTING

A quaternary referral otology and skull base center.

PATIENTS AND METHODS

A retrospective study of 1983 cases of vestibular schwannomas (VSs) with preoperative normal FN function, undergoing total excision with anatomical preservation of the nerve by enlarged translabyrinthine approach (ETLA) were included. FN status was recorded postoperatively at day 1, at discharge, and at 1-year follow-up and were analyzed in different tumor sizes.

RESULTS

At 1 year, 988 patients with House-Brackmann (H-B) grade I and II FN at day 1 after surgery, 958 (96.9%) maintained their status up-to 1 year. Of the 216 patients with H-B grade III at day 1 after surgery, 113 (52.3%) improved to H-B grade I and II. Similarly, of the 779 patients with H-B grade IV and VI FN function at day 1 after surgery, improvement to H-B III and H-B I and II were noted in 442 (56.7%) and 80 (10.3%) of patients, respectively. Intrameatal and extrameatal tumors upto 2 cm showed better recovery from H-B grade III to H-B I and II and from H-B grade IV and VI to H-B I and III when compared with extrameatal tumors >2 cm (p = 0.001).

CONCLUSION

Tumors of smaller sizes have good immediate postoperative FN results and recover well at the end of 1 year while more than 3 cm have poor outcomes and recover poorly at the end of 1 year. When the VSs reaches more than 1 cm, the HB I and II outcomes drop significantly.

What Is the Safety and Efficacy of Chemical Venous Thromboembolism Prophylaxis Following Vestibular Schwannoma Surgery?

OBJECTIVE

The benefit of routine chemical prophylaxis use for venous thromboembolism (VTE) prevention in skull base surgery is controversial. Chemical prophylaxis can prevent undue morbidity and mortality, however there are risks for hemorrhagic complications.

STUDY DESIGN

Retrospective case-control.

METHODS

A retrospective chart review of patients who underwent surgery for vestibular schwannoma from 2011 to 2016 was performed. Patients were divided by receipt of chemical VTE prophylaxis. Number of VTEs and hemorrhagic complications (intracranial hemorrhage, abdominal hematoma, and postauricular hematoma) were recorded.

RESULTS

One hundred twenty-six patients were identified, 55 received chemical prophylaxis, and 71 did not. All the patients received mechanical prophylaxis. Two patients developed a deep vein thrombosis (DVT) and one patient developed a pulmonary embolism (PE). All patients who developed a DVT or PE received chemical prophylaxis. There was no difference in DVT (p = 0.1886) or PE (p = 0.4365) between those who received chemical prophylaxis and those who did not. Five patients developed a hemorrhagic complication, two intracranial hemorrhage, three abdominal hematoma, and zero postauricular hematoma. All five patients with a complication received chemical prophylaxis (p = 0.00142). The relative risk of a hemorrhagic complication was 14.14 (95% CI = 0.7987-250.4307; p = 0.0778).

CONCLUSION

There was a significant difference between the number of hemorrhagic complications but not between numbers of DVT or PE. Mechanical and chemical prophylaxis may lower the risk of VTE but in our series, hemorrhagic complications were observed. These measures should be used selectively in conjunction with early ambulation.

Adaptive hybrid surgery analysis (AHSA) for adjuvant gamma knife radiosurgery treatment of vestibular schwannoma residuals

OBJECTIVES

Adaptive Hybrid Surgery Analysis (AHSA, Brainlab, Munich, Germany) is a software application generating in real-time conceptual dose plans for tumor residuals but has so far not been assessed for usability in a Gamma Knife (Elekta, Stockholm, Sweden) radiosurgery practice. We aimed to compare AHSA stereotactic radiosurgery dose plans with Leksell Gamma Plan (LGP, Elekta, Stockholm, Sweden) plans for adjuvant radiosurgical treatment of Vestibular Schwannoma (VS) residuals.

PATIENTS AND METHODS

In this retrospective comparative study, we compared the automatically calculated AHSA dose plans with clinical LGP treatment plans in 13 patients radiosurgically treated for VS residuals. We first created an LGP template based on our specific constraints to organs at risk (OAR), and a tumor prescription volume coverage of minimum 98%. As most proximal anatomy at risk is not manually contoured in our practice, OARs (i.e. brainstem, optic apparatus and cochlea) in the planning images were automatically segmented in Elements Anatomical Mapping and imported into the AHSA software for re-planning and comparison with the LGP dose plans.

RESULTS

There was no significant difference in tumor coverage and conformity index between the LGP and AHSA dose planning data, with the mean and maximal dose to the brainstem slightly higher in the latter.

CONCLUSION

The AHSA dose plans for adjuvant radiosurgical treatment of VS residuals were comparable to those of LGP used in our Gamma Knife practice, confirming the usability of AHSA in the management of Vestibular Schwannoma in a Gamma Knife practice.

Risk factors for postoperative meningitis after microsurgery for vestibular schwannoma

OBJECTIVE

Meningitis after microsurgery for vestibular schwannoma (VS) is a severe complication that results in high morbidity. However, few studies have focused on meningitis after VS surgery. The purpose of this study was to identify the risk factors for meningitis after VS surgery.

METHODS

We performed a retrospective analysis of all VS patients who underwent microsurgery and survived for at least 7 days after surgery, between 1 June 2015 and 30 November 2018 at West China Hospital of Sichuan University. Univariate and multivariate analyses were performed to identify the risk factors for postoperative meningitis (POM).

RESULTS

We enrolled 410 patients, 27 of whom had POM. Through univariate analysis, the factors of hydrocephalus (p = 0.018), Koos grade IV (p = 0.04), operative duration > 3 hours (p = 0.03) and intraoperative bleeding volume ≥400 ml (p = 0. 02) were significantly correlated with POM. The multivariate analysis showed that Koos grade IV (p = 0.04; OR = 3.19; 95% CI 1.032-3.190), operation duration > 3 hours (p = 0.03; OR = 7.927; 95% CI 1.043-60.265), and intraoperative bleeding volume ≥ 400 ml (p = 0.02; OR = 2.551; 95% CI 1.112-5.850) were the independent influencing factors of POM.

CONCLUSIONS

Koos grade IV, operation duration > 3 hours, and intraoperative blood loss ≥ 400 ml were identified as independent risk factors for POM after microsurgery for VS. POM also caused a prolonged hospital stay.

Hydroxyapatite cement cranioplasty for translabyrinthine surgery: A single institution experience

OBJECTIVE

To assess complication rates in hydroxyapatite cement (HAC) cranioplasty for translabyrinthine acoustic surgery compared with historical controls.

METHODS

Retrospective chart review of patients undergoing de novo translabyrinthine surgery with HAC cranioplasty without concurrent adipose tissue graft or additional material between 2010 and 2017 at a tertiary otology center.

RESULTS

Fifty-two patients underwent HAC cranioplasty during the study period. The average length of follow-up was 30.5 months. HAC cranioplasty was associated with acceptable rates of cerebrospinal fluid leak (3.8%), wound or intracranial infection (5.8%), need for unplanned revision surgery (9.6%), and all complications (15.3%). All complications occurred within 5 months of surgery. No delayed wound infections or implant extrusions occurred.

CONCLUSION

HAC cranioplasty has an acceptable complication profile for translabyrinthine surgery and is a viable alternative to abdominal fat grafting without associated donor site morbidity.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:206-211, 2020.

National Trends in Vestibular Schwannoma Surgery: Influence of Patient Characteristics on Outcomes

Objective To characterize current vestibular schwannoma (VS) surgery outcomes with a nationwide database and identify factors associated with increased complications and prolonged hospital course. Study Design Retrospective review utilizing the University HealthSystem Consortium national inpatient database. Setting US academic health centers. Subjects and Methods Data from patients undergoing VS surgery were analyzed over a 3-year time span (October 2012 to September 2015). Surgical outcomes, such as length of stay (LOS), complications, and mortality, were analyzed on the basis of race, sex, age, and comorbidities during the 30-day postoperative period. Results A total of 3697 VS surgical cases were identified. The overall mortality rate was 0.38%, and the overall complication rate was 5.3%. Advanced age significantly affected intensive care unit LOS, mortality, and complications ( P = .04). Comorbidities, including hypertension, obesity, and depression, also significantly increased complication rates ( P = .02). Sixty-eight patients (1.8%) had a history of irradiation, and they had a significantly increased LOS ( P = .03). Conclusion Modern VS surgery has a low mortality rate and a relatively low rate of complications. Several factors contribute to high complication rates, including age and comorbidities. These data will help providers in counseling patients on which treatment course might be best suited for them.

Anti-adhesive effect of poloxamer-based thermo-sensitive sol-gel in rabbit laminectomy model

Poloxamer-based thermo-sensitive sol-gel has been developed to reduce the incidence of postoperative scar formation at the laminectomy site. The purpose of this study was to evaluate the anti-adhesive effect of poloxamer based thermo-sensitive sol-gel compared to hyaluronate based solution after laminectomy, using a rabbit model. A thermo-sensitive anti-adhesive with a property of sol-gel transition was manufactured by a physical mixture of Poloxamer188/407, Chitosan and Gelatin. The viscosity in different temperatures was assessed. 72 adult New Zealand rabbits underwent lumbar laminectomy and were randomly divided into experimental (treated with the newly developed agent), positive (treated with hyaluronate based solution), and negative control groups. Each group was subdivided into 1 and 4-week subgroups. Gross and histological evaluations were performed to assess the extent of epidural adhesion. The experimental group showed significantly higher viscosity compared to the positive control group and showed a significant increase of viscosity as the temperature increased. Gross evaluation showed no statistically significant differences between the 1- and 4-week subgroups. However, histologic evaluation showed significant differences both in 1- and 4-week subgroups. Although the 4-week histologic results of the experimental and the positive control subgroups showed no significant difference, both subgroups revealed higher value compared to the negative control subgroup with regard to the ratio of adhesion less than 50 %. The new poloxamer based thermo-sensitive agent showed superior efficacy over the hyaluronate based agent at 1 week postoperatively. At 4 weeks postoperatively, there were no statistically significant differences between the two agents, although both showed efficacy over the sham group.

Staged resection of large acoustic neuromas

OBJECTIVE

Surgical removal of large (>3 cm) acoustic neuromas is associated with poor long-term facial nerve function results and higher complication rates. This study analyzes whether long term facial nerve function and the incidence of neurological and vascular complications is improved by resection of large acoustic neuromas in 2 or 3 stages.

PATIENTS AND METHODS

Among 660 patients who underwent surgical resection of acoustic neuromas between 1989 and 2002 by the senior author (J.M.K.), 34 (5%) patients underwent a staged resection of their large-sized tumors: stage I via a retrosigmoid craniotomy and stage II via a translabyrinthine approach. A retrospective chart review was performed. Tumor size, completeness of tumor removal, tumor recurrence, facial nerve function, and any complications were noted.

RESULTS:

The average tumor size was 4.4 cm with a mean postoperative length of follow-up of 6 years after the last surgery. Thirty-one patients underwent a 2-staged resection and 3 patients underwent a 3-staged resection. After their last surgery, 32 (94%) patients had excellent long-term facial function grades of House-Brackmann (H-B) I, one was H-B III, and one was H-B VI. All patients had a total or near-total (>98%) resection. There were no tumor recurrences on follow-up MRI scans. From these 71 operations, no patients required reoperation for a CSF leak. There were no deaths, strokes, hydrocephalus, or meningitis.

CONCLUSION:

In conjunction with the reported technical refinements, staged resection of large tumors significantly reduces morbidity and improves long-term facial nerve function. EBM rating: C.

Retrosigmoid Versus Translabyrinthine Approach for Acoustic Neuroma Resection: An Assessment of Complications and Payments in a Longitudinal Administrative Database

Object

Retrosigmoid (RS) and translabyrinthine (TL) surgery remain essential treatment approaches for symptomatic or enlarging acoustic neuromas (ANs). We compared nationwide complication rates and payments, independent of tumor characteristics, for these two strategies.

Methods

We identified 346 and 130 patients who underwent RS and TL approaches, respectively, for AN resection in the 2010-2012 MarketScan database, which characterizes primarily privately-insured patients from multiple institutions nationwide.

Results

Although we found no difference in 30-day general neurological or neurosurgical complication rates, in TL procedures there was a decreased risk for postoperative cranial nerve (CN) VII injury (20.2% vs 10.0%, CI 0.23–0.82), dysphagia (10.4% vs 3.1%, CI 0.10–0.78), and dysrhythmia (8.4% vs 2.3%, CI 0.08–0.86). Overall, there was no difference in surgical repair rates of CSF leak; however, intraoperative fat grafting was significantly higher in TL approaches (19.8% vs 60.2%, CI 3.95–9.43). In patients receiving grafts, there was a trend towards a higher repair rate after RS approach, while in those without grafts, there was a trend towards a higher repair rate after TL approach. Median total payments were $16,856 higher after RS approaches ($67,774 vs $50,918, p < 0.0001), without differences in physician or 90-day postoperative payments.

Conclusions 

Using a nationwide longitudinal database, we observed that the TL, compared to RS, approach for AN resection experienced lower risks of CN VII injury, dysphagia, and dysrhythmia. There was no significant difference in CSF leak repair rates. The payments for RS procedures exceed payments for TL procedures by approximately $17,000. Data from additional years and non-private sources will further clarify these trends.

Decision making in dissection range of temporal bone: refinements to enlarged translabyrinthine approach

The aim of the study was to describe the refinements to the classic enlarged translabyrinthine approach (ETLA) by modifying the bony dissection range of temporal bone and to analyze the main outcomes achieved in a series of vestibular schwannoma (VS) cases submitted to microsurgery by ETLA. This was a retrospective study of 382 patients who underwent VS surgical removal via ETLA between January 2001 and December 2012. Among those cases, 332 were via classic ETLA, while 28 cases were via ETLA with blind sac technique and middle ear eradication and 22 via transotic approach. Total tumor removal was achieved in 368 cases, whereas near total removal in 11 patients and subtotal in 3 patients. In cases of large VS (>3 cm) via classic ETLA, good short-term and long-term facial nerve function (HB I-II) was gained in 27.8 % (32/115) and 42.6 % (49/115) cases, respectively, meanwhile in VS operated via blind sac technique, good short-term (p = 0.048) and long-term (p = 0.044) facial nerve function was reached in 44.0 % (22/50) and 60.0 % (30/50) cases, respectively. Postoperative facial nerve function was proved to be better in modified ETLA group. CSF leakage occurred in 16 (4.2 %) patients via classic ETLA. In 115 cases of large VS (>3 cm), postoperative CSF leakage occurred in 10 (8.7 %) patients. Whereas in 50 cases via blind sac technique, none developed CSF leakage (p = 0.03). The incidence of CSF leakage was lower in modified ETLA group. Our refinements to classic ETLA by changing the temporal bone resection range provide a wide surgical field, well prevention of CSF leakage and preservation of facial nerve function in large VS.

Preoperative identification of facial nerve in vestibular schwannomas surgery using diffusion tensor tractography

OBJECTIVE

Facial nerve palsy is a common complication of treatment for vestibular schwannoma (VS), so preserving facial nerve function is important. The preoperative visualization of the course of facial nerve in relation to VS could help prevent injury to the nerve during the surgery. In this study, we evaluate the accuracy of diffusion tensor tractography (DTT) for preoperative identification of facial nerve.

METHODS

We prospectively collected data from 11 patients with VS, who underwent preoperative DTT for facial nerve. Imaging results were correlated with intraoperative findings. Postoperative DTT was performed at postoperative 3 month. Facial nerve function was clinically evaluated according to the House-Brackmann (HB) facial nerve grading system.

RESULTS

Facial nerve courses on preoperative tractography were entirely correlated with intraoperative findings in all patients. Facial nerve was located on the anterior of the tumor surface in 5 cases, on anteroinferior in 3 cases, on anterosuperior in 2 cases, and on posteroinferior in 1 case. In postoperative facial nerve tractography, preservation of facial nerve was confirmed in all patients. No patient had severe facial paralysis at postoperative one year.

CONCLUSION

This study shows that DTT for preoperative identification of facial nerve in VS surgery could be a very accurate and useful radiological method and could help to improve facial nerve preservation.

Complications of microsurgery of vestibular schwannoma

BACKGROUND

The aim of this study was to analyze complications of vestibular schwannoma (VS) microsurgery.

MATERIAL AND METHODS

A retrospective study was performed in 333 patients with unilateral vestibular schwannoma indicated for surgical treatment between January 1997 and December 2012. Postoperative complications were assessed immediately after VS surgery as well as during outpatient followup.

RESULTS

In all 333 patients microsurgical vestibular schwannoma (Koos grade 1: 12, grade 2: 34, grade 3: 62, and grade 4: 225) removal was performed. The main neurological complication was facial nerve dysfunction. The intermediate and poor function (HB III-VI) was observed in 124 cases (45%) immediately after surgery and in 104 cases (33%) on the last followup. We encountered disordered vestibular compensation in 13%, permanent trigeminal nerve dysfunction in 1%, and transient lower cranial nerves (IX-XI) deficit in 6%. Nonneurological complications included CSF leakage in 63% (lateral/medial variant: 99/1%), headache in 9%, and intracerebral hemorrhage in 5%. We did not encounter any case of meningitis.

CONCLUSIONS

Our study demonstrates that despite the benefits of advanced high-tech equipment, refined microsurgical instruments, and highly developed neuroimaging technologies, there are still various and significant complications associated with vestibular schwannomas microsurgery.

Evaluation of the increased use of partial resection of large vestibular schwanommas: facial nerve outcomes and recurrence/regrowth rates

OBJECTIVE

To determine whether partial tumor removal in large vestibular schwannoma improves facial nerve outcomes while maintaining a low risk of tumor regrowth/recurrence.

STUDY DESIGN

Retrospective chart review and prospective database.

SETTING

Tertiary neurotologic referral center.

PATIENTS

Four hundred patients with a vestibular schwannoma of 2.5 cm or greater in maximum diameter undergoing translabyrinthine microsurgical resection from 2001 to 2011. There were 325 gross total resections (GTR), 44 near total resections (NTR), and 31 subtotal resections (STR), with an overall mean tumor size of 3.2 cm (standard deviation, 0.7).

INTERVENTION(S)

Translabyrinthine surgical tumor resection.

MAIN OUTCOME MEASURES

House-Brackmann (H-B) facial nerve grade postoperatively and at 1 year, tumor regrowth/recurrence (≥2 mm), additional treatment, and complications.

RESULTS

Higher rates of H-B facial nerve Grades I and II were achieved at both the postoperative and 1-year follow-ups in the NTR (78%, 97%) and STR (71%, 96%) groups compared with GTR (53%, 77%) (p ≤ 0.001). Eye treatment, medical or surgical, was required more often in GTR (28.0%) than NTR and STR (8% and 21%, respectively, p ≤ 0.04), with no other differences in complications. The NTR and STR groups had a significantly higher rate of regrowth than GTR resection (21% and 22% versus 3%) (p ≤ 0.001) at average follow-up times of 3.7, 3.7, and 5.1 years, respectively, and need for further treatment occurred at a higher rate, although infrequently, in NTR and STR (2% and 10% versus 0%) (p ≤ 0.001).

CONCLUSION

Near total and subtotal removal in large tumors are viable treatment options to maintain facial nerve function. During the follow-up period examined in this study, there was a low risk of need for further treatment. Longer-term follow-up is needed to better assess the need for retreatment in patients treated with NTR and STR.

Preservation of Facial Nerve Function Repaired by Using Fibrin Glue-Coated Collagen Fleece for a Totally Transected Facial Nerve during Vestibular Schwannoma Surgery

Recently, the increasing rates of facial nerve preservation after vestibular schwannoma (VS) surgery have been achieved. However, the management of a partially or completely damaged facial nerve remains an important issue. The authors report a patient who was had a good recovery after a facial nerve reconstruction using fibrin glue-coated collagen fleece for a totally transected facial nerve during VS surgery. And, we verifed the anatomical preservation and functional outcome of the facial nerve with postoperative diffusion tensor (DT) imaging facial nerve tractography, electroneurography (ENoG) and House-Brackmann (HB) grade. DT imaging tractography at the 3rd postoperative day revealed preservation of facial nerve. And facial nerve degeneration ratio was 94.1% at 7th postoperative day ENoG. At postoperative 3 months and 1 year follow-up examination with DT imaging facial nerve tractography and ENoG, good results for facial nerve function were observed.

Conservative management, gamma-knife radiosurgery, and microsurgery for acoustic neurinomas: A systematic review of outcome and risk of three therapeutic options

Conservative management, gamma-knife (GK) radiosurgery, and microsurgery are therapeutic options for acoustic neurinomas (ANs). To determine the outcomes and risks of these methods this systematic review analyzed data from 903 patients with conservative management, 1475 with GK radiosurgery, and 5005 with microsurgery from 38 studies identified in MEDLINE searches. Conservative management over a 3.1-year period showed that 51% of ANs showed a tumor growth, an average tumor growth rate was 1.87 mm year-1, 20% of ANs ultimately required surgical intervention, and a third of the patients lost useful hearing. GK radiosurgery significantly reduced the percentage of ANs that enlarged, to 8%, and reduced the percentage that underwent microsurgery to 4.6% over a 3.8-year period. Microsurgery removed 96% of ANs totally, with tumor recurrence, mortality, and major disability rates of 1.8%, 0.63%, and 2.9%, respectively. The majority of ANs grow slowly, but ultimately require intervention. Carrying the risk of hearing loss, conservative management should be supplemented with close follow-up. With a low rate of morbidity, GK radiosurgery suppresses tumor growth and provides good tumor control. Microsurgery provides the best tumor control, although mortality and morbidity are not completely eliminated.

Improved facial nerve outcomes using an evolving treatment method for large acoustic neuromas

OBJECTIVE

To describe a successful paradigm for the treatment of large acoustic neuromas (vestibular schwannomas).

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

The charts of 2,875 acoustic neuroma patients at Michigan Ear Institute were reviewed to identify 153 patients who underwent surgical resection for large acoustic neuromas (>=3 cm) between 2000 and 2009.

INTERVENTION(S)

Staged surgical resection or single stage surgery with or without adjuvant stereotactic radiosurgery.

MAIN OUTCOME MEASURE(S)

Postoperative facial nerve outcomes are reported using the House-Brackmann (HB) facial nerve grading scale and compared with historical controls from a literature review. Rates of adverse outcomes are also reported.

RESULTS

Seventy-five patients underwent staged surgical resection of their tumors, whereas 78 patients underwent either single stage surgery or surgery with subsequent stereotactic radiosurgery. Eighty-one percent of patients in the staged surgical resection group had a postoperative HB Grade I or II facial nerve function compared with 75% in the single stage surgical group. Overall, 78% of patients in the current study had HB Grade I or II after treatment compared with a mean of 53% in the literature for similar sized tumors. Our methods including the decision to use staged surgery when necessary, dissection of tumor with stimulating dissector-directed intraoperative monitoring, and use of adjuvant stereotactic radiosurgery are described.

CONCLUSION

Using the described paradigm, large acoustic neuromas can be successfully treated with either staged or single-stage surgical resection with or without adjuvant radiosurgery to obtain more favorable facial nerve outcomes than historically reported controls while minimizing morbidity for the patient.

Surgery for vestibular schwannomas: a systematic review of complications by approach

Object

Various studies report outcomes of vestibular schwannoma (VS) surgery, but few studies have compared outcomes across the various approaches. The authors conducted a systematic review of the available data on VS surgery, comparing the different approaches and their associated complications.

Methods

MEDLINE searches were conducted to collect studies that reported information on patients undergoing VS surgery. The authors set inclusion criteria for such studies, including the availability of follow-up data for at least 3 months, inclusion of preoperative and postoperative audiometric data, intraoperative monitoring, and reporting of results using established and standardized metrics. Data were collected on hearing loss, facial nerve dysfunction, persistent postoperative headache, CSF leak, operative mortality, residual tumor, tumor recurrence, cranial nerve (CN) dysfunction involving nerves other than CN VII or VIII, and other neurological complications. The authors reviewed data from 35 studies pertaining to 5064 patients who had undergone VS surgery.

Results

The analyses for hearing loss and facial nerve dysfunction were stratified into the following tumor categories: intracanalicular (IC), size (extrameatal diameter) < 1.5 cm, size 1.5–3.0 cm, and size > 3.0 cm. The middle cranial fossa approach was found to be superior to the retrosigmoid approach for hearing preservation in patients with tumors < 1.5 cm (hearing loss in 43.6% vs 64.3%, p < 0.001). All other size categories showed no significant difference between middle cranial fossa and retrosigmoid approaches with respect to hearing loss. The retrosigmoid approach was associated with significantly less facial nerve dysfunction in patients with IC tumors than the middle cranial fossa method was; however, neither differed significantly from the translabyrinthine corridor (4%, 16.7%, 0%, respectively, p < 0.001). The middle cranial fossa approach differed significantly from the translabyrinthine approach for patients with tumors < 1.5 cm, whereas neither differed from the retrosigmoid approach (3.3%, 11.5%, and 7.2%, respectively, p = 0.001). The retrosigmoid approach involved less facial nerve dysfunction than the middle cranial fossa or translabyrinthine approaches for tumors 1.5–3.0 cm (6.1%, 17.3%, and 15.8%, respectively; p < 0.001). The retrosigmoid approach was also superior to the translabyrinthine approach for tumors > 3.0 cm (30.2% vs 42.5%, respectively, p < 0.001). Postoperative headache was significantly more likely after the retrosigmoid approach than after the translabyrinthine approach, but neither differed significantly from the middle cranial fossa approach (17.3%, 0%, and 8%, respectively; p < 0.001). The incidence of CSF leak was significantly greater after the retrosigmoid approach than after either the middle cranial fossa or translabyrinthine approaches (10.3%, 5.3%, 7.1%; p = 0.001). The incidences of residual tumor, mortality, major non-CN complications, residual tumor, tumor recurrence, and dysfunction of other cranial nerves were not significantly different across the approaches.

Conclusions

The middle cranial fossa approach seems safest for hearing preservation in patients with smaller tumors. Based on the data, the retrosigmoid approach seems to be the most versatile corridor for facial nerve preservation for most tumor sizes, but it is associated with a higher risk of postoperative pain and CSF fistula. The translabyrinthine approach is associated with complete hearing loss but may be useful for patients with large tumors and poor preoperative hearing.

Staged resection of large vestibular schwannomas

OBJECT

Staged resection of large vestibular schwannomas (VSs) has been proposed as a strategy to improve facial nerve outcomes and morbidity. The authors report their experience with 2-stage resections of large VSs and analyze the indications, facial nerve outcomes, surgical results, and complications. The authors compare these results with those of a similar cohort of patients who underwent a single-stage resection.

METHODS

A retrospective review of all patients (age > 18 years) who underwent surgery from 2002 to 2010 for large (≥ 3 cm) VSs at the authors' institution with a minimum of 6 months follow-up was undertaken. A first-stage retrosigmoid approach (without meatal drilling) was performed to remove the cerebellopontine angle portion of the tumor and to decompress the brainstem. A decision to stage the operation was made intraoperatively if there was cerebellar or brainstem edema, excessive tumor adherence to the facial nerve or brainstem, a poorly stimulating facial nerve, or a thinned or splayed facial nerve. A second-stage translabyrinthine approach was performed at a later date to remove the remaining tumor. The single-stage resection consisted of a retrosigmoid approach with meatal drilling. Patient charts were evaluated for tumor size, extent of resection, tumor recurrence, House-Brackmann facial nerve function grade, and complications.

RESULTS

Twenty-eight and 19 patients underwent 2- or single-stage resection of a large VS, respectively. The average tumor size was 3.9 cm (range 3.2-7 cm) in the 2-stage group and 3.9 cm (range 3.1-5 cm) in the single-stage group. The mean follow-up was 36 ± 19 months in the 2-stage group versus 24 ± 14 months in the single-stage group. Gross-total or near-total resection was achieved in 27 (96.4%) of 28 patients in the 2-stage group and 15 (79%) of 19 patients in the single-stage group (p < 0.01). Anatomical facial nerve preservation was achieved in all but 1 patient (94.7%), and there were no recurrences on follow-up imaging in the 2-stage group. Good facial nerve functional outcome (House-Brackmann Grades I and II) at last follow-up was achieved in 23 (82%) of 28 patients in the 2-stage group and 10 (53%) of 19 patients in the single-stage group (p < 0.01). Cerebrospinal fluid leak-related complications (intracranial hypotension, blood patch, and lumboperitoneal shunt for pseudomeningocele) were more common in the 2-stage group. There were no postoperative strokes, hemorrhages, or deaths in either group.

CONCLUSIONS

The authors' results suggest that staged resection of large VSs may potentially achieve better facial nerve outcomes. There does not appear to be added neurological morbidity with staged resections.

[Results in the surgical treatment of giant acoustic neuromas]

INTRODUCTION AND OBJECTIVES

To compare the results obtained in the resection of 21 giant vestibular schwannomas via retrosigmoid (RS) and combined retrosigmoid/translabyrinthine (RS/TL) approaches with respect to intra- and postoperative complications, facial nerve preservation and postsurgical sequelae.

METHODS

This was a retrospective study of 21 patients who underwent a resection of a giant vestibular neuroma according to the Tos & Thomsen Scale (greater than or equal to 4 centimetres) in a tertiary care centre in the period between 2000 and 2008. We present the most significant characteristics of the series studied and the analysis of the advantages and inconveniences of each approach. We also analyse the results regarding facial nerve function preservation.

RESULTS

We highlight the absence of mortality in the 21-patient group. There were no important intraoperative complications. Total resection of the lesion was achieved in the 87% of the cases, with facial nerve preservation of 73% using the combined RS/TL approach, in comparison to 40% using the RS. Facial nerve function after two years was acceptable or good in 67% (including those with heteronerve anastomosis). A global percentage of 14.3% of cerebrospinal liquid fistula was observed, as well as 9.5% of meningitis.

CONCLUSIONS

The results of the study demonstrate that the combined retrosigmoid translabyrinthine approach for giant schwannoma treatment offers increased facial nerve preservation and lower morbidity, constituting an important option in the treatment of this kind of tumours thanks to a multidisciplinary approach.

Surgical Results and Technical Refinements in Translabyrinthine Excision of Vestibular Schwannomas

BACKGROUND:

Vestibular schwannomas (VSs) are the most common cerebellopontine angle tumors, accounting for 75% of all lesions in this location.

OBJECTIVE:

To evaluate the results after removal of VS through the enlarged translabyrinthine approach, which is a widening of the classic translabyrinthine approach that gives larger access and provides more room to facilitate tumor removal and to minimize surgery-related morbidities.

METHODS:

This was a retrospective study of 1865 patients who underwent VS excision through the enlarged translabyrinthine approach between 1987 and 2009. Mean age was 50.39 years. Mean tumor size was 1.8 cm. Median follow-up was 5.7 years.

RESULTS:

Total removal was achieved in 92.33% of cases; 143 patients had incomplete resection with evidence of regrowth in 8. In the 1742 previously untreated patients, anatomic preservation of facial nerve was achieved in 1661 cases (95.35%), and House-Brackmann grade I or II was reached in 1047 patients (59.87%). Facial nerve outcome was significantly better in tumors ⩽ 20 mm. Surgical complications included cerebrospinal fluid leakage in 0.85%, meningitis in 0.10%, intracranial bleeding in 0.80%, non--VII/VIII cranial nerve palsy in 0.96%, cerebellar ataxia in 0.69%, and death in 0.10%. The technical modifications that evolved with increasing experience are described.

CONCLUSION:

The enlarged translabyrinthine approach is a safe and effective approach for the removal of VS. In our experience, the complication rate is very low and tumor size is still the main factor influencing postoperative facial nerve function with a cutoff point at around 20 mm.

Evaluation of Fibrin Sealants for Central Nervous System Sealing in the Mongrel Dog Durotomy Model

BACKGROUND:

Watertight repair of the dura is imperative after neurosurgical procedures involving the brain or spinal cord because inadequately treated leakage of cerebrospinal fluid (CSF) from punctured dura can have serious consequences such as meningitis, arachnoiditis, or epidural abscess.

OBJECTIVE:

To assess the efficacy of Evicel Fibrin Sealant (Human) to prevent CSF leakage using a 2.0-cm durotomy mongrel dog repair model and to compare the tissue response with Tisseel (a fibrin sealant) and Duraseal (a synthetic polyethylene glycol [PEG] hydrogel sealant).

METHODS:

The canine durotomy repair model was used. This well-characterized model assesses the ability of sealants to achieve intraoperative watertight seals of the dura mater, as well as long-term safety and efficacy. This study included 27 mongrel dogs and had a 28-day duration.

RESULTS:

The 3 sealants were 100% effective in preventing CSF leakage intraoperatively at 15 mm Hg. The 2 fibrin sealants were 100% effective in postoperative sealing; the PEG hydrogel was not. Microscopically, the tissue changes induced by Evicel at the durotomy site were similar in nature except for foamy macrophages seen only with the PEG hydrogel. The extent and severity of adhesions at 28 days were less with the fibrin sealants than with the PEG hydrogel.

CONCLUSION:

Evicel, a fibrin sealant, was safe and effective in achieving and maintaining a watertight seal of the dura. The performance of the fibrin sealants was similar to that of the synthetic PEG hydrogel sealant with the exception of a Duraseal seal, which leaked.

Long-term facial nerve function evaluation following surgery for large acoustic neuromas via retrosigmoid transmeatal approach

PURPOSE

By evaluating the postoperative facial nerve function of large acoustic neuromas, the purpose of this study was to analyze the factors that influence the facial nerve function outcome and to explore the surgical strategy for large acoustic neuromas.

METHODS

A retrospective study of surgical outcome was performed on 89 patients with large acoustic neuromas. All operations were performed via the retrosigmoid transmeatal approach using the intraoperative electrophysiological monitoring.

RESULTS

Gross total resection was performed in 38 (42.7%) of the 89 patients, near total resection in 35 (39.3%), and subtotal resection in 16 (18.0%). The facial nerve was anatomically intact at the end of surgery in 83 (93.3%) patients. At 1 year after surgery, 48 (53.9%) patients had good facial nerve function (House-Brackmann (HB) Grades I-II), 23 (25.8%) patients had regular facial nerve function (HB Grades III-IV), and 18 (20.2%) patients had poor facial nerve function (HB Grades V-VI).

CONCLUSIONS

For large acoustic neuromas, the goal of complete tumor resection and preservation of acceptable facial nerve function can be attained via the retrosigmoid transmeatal approach, using the intraoperative facial nerve monitoring. The surgical strategy of near total resection is indicated for the large acoustic neuromas with severe adherence or inclusion in order to preserve facial nerve function.

Functional outcome after complete surgical removal of giant vestibular schwannomas

OBJECT

The authors evaluated the outcome of radical surgery in a consecutive series of patients with giant vestibular schwannomas (VSs).

METHODS

Fifty patients with VSs > 4.0 cm in maximal extrameatal diameter were included in this retrospective study (Group A). The group was compared with a matched group of 167 patients with VSs < 3.9 cm (Group B). In all cases the retrosigmoid approach was used. Outcome measures included completeness of tumor removal, facial nerve function, hearing, and the surgery-related complication rate.

RESULTS

The mean tumor size in Group A was 4.4 cm and that in Group B was 2.3 cm. Total removal was achieved in all Group A patients and in 97.6% of Group B patients. The anatomical integrity of the facial nerve was preserved in 92% in Group A and in 98.8% in Group B. At last follow-up 75% of the patients with giant VSs had excellent or good facial nerve function, 19% had fair function, and 6% had poor function. In 33% of patients (3 cases) with good preoperative hearing level, it was preserved. Newly developed lower cranial nerve dysfunction occurred in 3 patients but proved to be temporary in 2 of them. A CSF leak developed in 6% of those who not previously undergone surgery. Compared with Group B, a significant difference was found only in the rates of the following parameters: excellent facial nerve function, useful and good hearing, lower cranial nerve dysfunction, and blood collection (p < 0.05). The perioperative mortality rate in both groups was 0%.

CONCLUSIONS

In patients with a giant VS, total tumor removal can be achieved via the retrosigmoid approach with a 0% mortality rate and low morbidity rate, especially with regards to facial nerve function. In selected cases even hearing preservation is possible. Tumor size significantly correlates with postoperative outcome.

Less than 1% cerebrospinal fluid leakage in 1,803 translabyrinthine vestibular schwannoma surgery cases

OBJECTIVE

To determine the incidence rate of cerebrospinal fluid (CSF) leak after translabyrinthine vestibular schwannoma surgery since the alteration of the surgical procedure. To compare with previous series and other series in literature.

STUDY DESIGN

Database analysis.

SETTING

Tertiary referral neurotologic private practice.

PATIENTS

A series of 1,803 patients who underwent translabyrinthine vestibular schwannoma surgery between 1993 and 2009. The result of this group was compared with corresponding series.

INTERVENTION

Translabyrinthine and extended translabyrinthine vestibular schwannoma surgery. Literature review and comparison.

MAIN OUTCOME MEASURES

Rates of CSF leak in this series and historical perspective of the outcome.

RESULTS

Fifteen patients (0.8%) of 1,803 cases had CSF leaks. The method used since 1993 has shown a significant improvement compared with major case series of the last 10 years.

CONCLUSION

The methods used in translabyrinthine vestibular schwannoma surgery in our center can reduce CSF leakage to an absolute minimum. Compared with all large series, this could be a new era of translabyrinthine vestibular schwannoma surgery.

Differences in clinical results after LINAC-based single-dose radiosurgery versus fractionated stereotactic radiotherapy for patients with vestibular schwannomas

PURPOSE

To evaluate the outcomes of patients with vestibular schwannoma (VS) treated with fractionated stereotactic radiotherapy (FSRT) vs. those treated with stereotactic radiosurgery (SRS).

METHODS AND MATERIALS

This study is based on an analysis of 200 patients with 202 VSs treated with FSRT (n = 172) or SRS (n = 30). Patients with tumor progression and/or progression of clinical symptoms were selected for treatment. In 165 out of 202 VSs (82%), RT was performed as the primary treatment for VS, and for 37 VSs (18%), RT was conducted for tumor progression after neurosurgical intervention. For patients receiving FSRT, a median total dose of 57.6 Gy was prescribed, with a median fractionation of 5 x 1.8 Gy per week. For patients who underwent SRS, a median single dose of 13 Gy was prescribed to the 80% isodose.

RESULTS

FSRT and SRS were well tolerated. Median follow-up time was 75 months. Local control was not statistically different for both groups. The probability of maintaining the pretreatment hearing level after SRS with doses of < or =13 Gy was comparable to that of FSRT. The radiation dose for the SRS group (< or =13 Gy vs. >13 Gy) significantly influenced hearing preservation rates (p = 0.03). In the group of patients treated with SRS doses of < or =13 Gy, cranial nerve toxicity was comparable to that of the FSRT group.

CONCLUSIONS

FSRT and SRS are both safe and effective alternatives for the treatment of VS. Local control rates are comparable in both groups. SRS with doses of < or =13 Gy is a safe alternative to FSRT. While FSRT can be applied safely for the treatment of VSs of all sizes, SRS should be reserved for smaller lesions.

Surgery for large vestibular schwannoma: residual tumor and outcome

OBJECTIVE

To evaluate clinical outcome with regard to the amount of residual tumor after surgery for large vestibular schwannoma.

PATIENTS

Between January 2000 and December 2005, 51 large vestibular schwannoma tumors with extrameatal diameter of 2.6 cm or greater (mean, 32 mm; median, 30 mm; range, 26-50 mm) were operated using the translabyrinthine approach. The extent of the resection was intraoperatively estimated as complete, near, and subtotal. The amount of residual tumor was measured, and the shape and localization was scored on gadolinium-enhanced magnetic resonance imaging (MRI). Correlation between intraoperative and MRI assessment was performed using the Fisher's exact test. Potential growth of residual tumor was documented with frequent MRI follow-up. Postoperative facial nerve function was classified according to the House-Brackmann classification.

RESULTS

Complete resection was performed in 26% of the patients, near-total resection in 58%, and subtotal resection in 16%. Magnetic resonance imaging showed residual tumor in 46% of patients (mean, 16.7 mm; SD, +/-8, range, 5-36 mm). Postoperative facial nerve function was House-Brackmann Grades I to II in 78% of the patients. The intraoperative assessment of near-total resection did not correlate with postoperative MRI (p = 0.25). Postoperative MRI showed either no residual tumor or residue that should actually have been classified as a subtotal resection. After a follow-up of 4 years (49 mo; mean, 48 mo), 94% of patients did not show changes on MRI.

CONCLUSION

Tumor control with good facial nerve function could be obtained in most patients. Intraoperative assessment did not correlate with the amount of residual tumor on postoperative MRI. Objective documentation with postoperative MRI to measure the extent of removal is therefore mandatory.

Staging in vestibular schwannoma surgery: a modified technique

The authors herein propose the staged excision as a novel strategy to preserve facial nerve and minimize complication during microsurgery of large vestibular schwannoma (VS). At the first stage, for reducing mass effect on the brain stem and cerebellum, subtotal tumor resection was performed via a retrosigmoid craniotomy without intervention of meatal portion of tumor. With total resection of the remaining tumor, the facial nerve was decompressed and delineated during the second stage translabyrinthine approach at a later date. A 38-year-old female who underwent the staging operation for resection of her huge VS is illustrated.

Surgery of extra-axial tumors of the cerebral base

Because of the complex structure of the cranial base and its close proximity to cranial nerves and vessels, surgery in this area is associated with considerable risk of morbidity and mortality. Multiple approaches to each part of the cranial base have been developed over the past few decades, ranging from small modifications of more traditional approaches to complex and sophisticated new techniques. However, experience has shown that optimal outcome is achieved if the selected approach is not associated with significant approach-related morbidity. Furthermore, not all cranial base tumors can be cured by surgery. The selection of operative approach and the goal of surgery should be part of the whole treatment strategy. The attempt to achieve complete resection can, therefore, be justified only if the associated long-term morbidity is minimal. Refinements of the traditional retrosigmoid suboccipital approach have made it the most effective and safe approach, the "gold standard" for lesions in the cerebellopontine angle. On the other hand, in some basal tumors, e.g., chordomas and chondrosarcomas, the approach has to be selected individually and must always be tailored to the characteristics of the particular tumor, its location, and the patient's expectations. The expertise of the surgeon is not reflected in his or her ability to perform the most complex approaches but in the ability to select the approach that affords both removal of the tumor and preservation of patient's neurological function and quality of life.

Mitomycin protection of peridural fibrosis in lumbar disc surgery

Object

In this prospective, randomized clinical study the authors sought to evaluate the effects of locally applied mitomycin C on peridural fibrosis during lumbar microdiscectomy.

Methods

Patients undergoing lumbar disc surgery were randomly divided into 2 groups. Thirty patients had 1 mg/ml mitomycin C applied at the site of discectomy for 5 minutes, and 30 age- and sex-matched patients underwent lumbar microdiscectomy without mitomycin C application as the control group. The groups were compared for degree of postoperative neurological function, radicular/back pain, and degree of peridural fibrosis on MR imaging 6 months after the operation.

Results

The median follow-up was 18 months. No serious drug adverse effects and no clinically significant laboratory adverse effects were reported in patients in the mitomycin C group. Patients in both groups showed similar clinical recoveries postoperatively. On postoperative evaluation of the MR images, pain scores, and neurological function, patients given mitomycin C have shown no reduction of peridural fibrosis either clinically or radiographically.

Conclusions

Mitomycin C is easy to use and safe in patients undergoing lumbar microdiscectomy. However, no benefit was observed either clinically or radiographically in this study.

Local application of low-dose Depo-Medrol is effective in reducing immediate postoperative back pain

This prospective, randomised case-control study was made to determine effectiveness of low-dose Depo-Medrol applied to the affected nerve root after discectomy. Fifty seven patients with L4-5 or L5-S1 single level disc herniation with unilateral leg pain were selected for the study and were divided in two groups. Twenty eight patients were in the control group and 29 in the steroid group. Discectomy was done after flavotomy in all patients. In the steroid group low-dose 40 mg Depo-Medrol soaked Gelfoam was applied over the affected nerve root after discectomy while in the control group neither saline nor plain Gelfoam was applied to affected root. Postoperatively, patients were asked to evaluate backache using VAS which was compared statistically using the unpaired t test. Statistical difference was significant (p < 0.0001) regarding postoperative VAS during the first month and then it became insignificant. Results show that local application of low-dose Depo-Medrol is helpful in reducing immediate postoperative backache after discectomy, but it is not effective in the long-term.

Tumor-volume changes after radiosurgery for vestibular schwannoma: implications for follow-up MR imaging protocol

BACKGROUND AND PURPOSE

The outcome of radiosurgery for vestibular schwannoma (VS) is assessed by posttreatment measurement of tumor size and could be influenced by the timing and quality of the assessment. This study evaluates the volumetric changes of VS after radiosurgery and proposes a radiologic follow-up program.

MATERIALS AND METHODS

Of 142 patients with VS treated with radiosurgery, we selected patients who were followed at least 3 times during a minimum of 32 months with a T1-weighted gadolinium-enhanced high-resolution 3D MR imaging examination identical to the pretreatment MR imaging. Forty-five patients were identified with a mean follow-up of 50 months (range, 32-78 months). Pre- and posttreatment tumor volumes were calculated by using BrainSCAN software by manually contouring tumors on each MR imaging study. Volume changes of >13% were defined as events.

RESULTS

At last follow-up MR imaging, volumes were smaller in 37 (82.2%) of the 45 patients. Eleven (29.7%) of these 37 tumors showed transient swelling preceding regression, with a median time to regression of 34 months (range, 20-55 months). Seven (15.6%) of the 45 tumors had volume progression compared with the tumor on pretreatment MR imaging studies. Of these 7 tumors, 3, however, had volume regression compared with the preceding MR imaging study, and in 4, volume progression was ongoing. One tumor remained the same.

CONCLUSIONS

Tumor-volume measurements by standardized T1-weighted gadolinium-enhanced high-resolution 3D MR imaging follow-up protocols revealed good local control of VS after radiosurgery. The first-follow-up MR imaging at 2 years and the second at 5 years postradiosurgery differentiated transient progression from ongoing progression and may prevent unnecessary therapeutic interventions.