Staged resection of large acoustic neuromas

Staged Resection of Difficult-to-Treat Intracranial Meningiomas: A Systematic Review of the Indications, Surgical Approaches, and Postoperative Outcomes

Introduction  Meningiomas-the most common extra-axial tumors-are benign, slow-growing dural-based lesions that can involve multiple cranial fossae and can progress insidiously for years until coming to clinical attention secondary to compression of adjacent neurovascular structures. For complex, multicompartmental lesions, multistaged surgeries have been increasingly shown to enhance maximal safe resection while minimizing adverse sequela. Here, we systematically review the extant literature to highlight the merits of staged resection. Methods  PubMed, Scopus, and Web of Science databases were queried to identify articles reporting resections of intracranial meningiomas using a multistaged approach, and articles were screened for possible inclusion in a systematic process performed by two authors. Results  Of 118 identified studies, 36 describing 169 patients (mean age 42.6 ± 21.3 years) met inclusion/exclusion criteria. Petroclival lesions comprised 57% of cases, with the most common indications for a multistaged approach being large size, close approximation of critical neurovascular structures, minimization of brain retraction, identification and ligation of deep vessels feeding the tumor, and resection of residual tumor found on postoperative imaging. Most second-stage surgeries occurred within 3 months of the index surgery. Few complications were reported and multistaged resections appeared to be well tolerated overall. Conclusions  Current literature suggests multistaged approaches for meningioma resection are well-tolerated. However, there is insufficient comparative evidence to draw definitive conclusions about its advantages over an unstaged approach. There are similarly insufficient data to generate an evidence-based decision-making framework for when a staged approach should be employed. This highlights the need for collaborative efforts among skull base surgeons to establish an evidentiary to support the use of staged approaches and to outline those indications that merit such an approach.

Two-Stage Surgical Management for Acutely Presented Large Vestibular Schwannomas: Report of Two Cases

The surgical management of vestibular schwannomas should be based on their presentation, neuro-imaging findings, surgeons' expertise, and logistics. Multi-stage surgery can be beneficial for large-sized lesions with acute presentations. Herein, we highlighted the indications for two cases managed initially through the retrosigmoid and, subsequently, translabyrinthine approaches. The first case presented with acute balance and gait issues and a long history of hearing loss and blurred vision. Neuroimaging findings revealed a cerebellopontine angle lesion, resembling a vestibular schwannoma, with significant brainstem compression and hydrocephalus. Due to the rapidly deteriorating clinical status and large-sized tumor, we first proceeded with urgent decompression via a retrosigmoid approach, followed by gross total resection via a translabyrinthine approach two weeks later. The second case presented with gradually worsening dizziness and hemifacial numbness accompanied by acute onset severe headaches and hearing loss. Neuroimaging findings showed a large cerebellopontine angle lesion suggestive of a vestibular schwannoma with acute intratumoral hemorrhage. Given the acute clinical deterioration and large size of the tumor, we performed urgent decompression with a retrosigmoid approach followed by gross total resection through a translabyrinthine approach a week later. Post-surgery, both patients showed excellent recovery. When managing acutely presented large-sized vestibular schwannomas, immediate surgical decompression is vital to avoid permanent neurological deficits.

Large Vestibular Schwannoma: A Two-Stage Surgery

Treatment of large vestibular schwannoma (VS) has historically centered on total resection of the lesion. Staged surgery has been used for VS that is highly vascularized, unexpected events during surgery, and thinned and stretched facial nerve with serious adherence causing difficult dissection. We present a case of a patient with a large VS resected through a two-stage surgery through the same retrosigmoid craniotomy.

Hypofractionated stereotactic radiotherapy for large vestibular schwannomas and the impact of pre-radiation debulking surgery on dosimetry and clinical outcomes

Introduction:

This study was aimed to evaluate the outcomes of patients with large (>2 cm in great diameter) vestibular schwannomas (VSs) treated with hypofractionated stereotactic radiotherapy (HFSRT) compared to small (<2 cm) ones and the impact of debulking surgery prior to radiation for large VSs.

Methods:

Fifty-nine patients with VSs treated with HFSRT (25 Gy in 5 fractions) were evaluated by tumour size and surgical status. Patients were divided based on tumour size: small VSs (n = 42) and large VSs (n = 17). The large group was further divided into the groups of pre-treatment debulking surgery (n = 8) and no surgery (n = 9). Rates of tumour control, brainstem necrosis and neurologic dysfunction were assessed following treatment. Pre-surgical magnetic resonance imaging (MRI) were used to generate hypothetical HFSRT plans to compare the effect of debulking surgery on dosimetry. Normal tissue complication probability (NTCP) modelling was performed to compare toxicity probabilities with and without surgical debulking in large VSs.

Results:

There was no statistical difference of tumour control rate between small and large VSs with 100% for small tumours and 94·1% for large tumours (p = 0·12), respectively. In large VSs patient, the tumour control rate of HFSRT was 100% (8/8) for surgically debulked patients and 89% (8/9) for non-surgically debulked patients (p = 0·35). There were no patients who experienced brainstem necrosis or progression of facial and trigeminal nerve symptoms after HFSRT in the entire groups of patients. Surgical debulking large VSs did not change the maximum point dose of brainstem (p = 0·98), but significantly decreased volumes of VSs and changed the minimum dose to the hottest 0·5 cc of tumour (p = 0·016) as well as the volume receiving at least 23 Gy (p = 0·023). NTCP modelling revealed very low rates (average < 1%) of brainstem toxicity with or without surgical debulking, but there was a significant difference favoring surgery (p < 0·05).

Conclusions:

HFSRT is a safe and effective treatment for both small and large VSs and is a viable option for patients with large VSs who cannot undergo surgery, if NTCP of pre-debulking HFSRT dosimetry is lower.

Applicability of contemporary quality indicators in vestibular surgery-do they accurately measure tumor inherent postoperative complications of vestibular schwannomas?

Background

Due to rising costs in health care delivery, reimbursement decisions have progressively been based on quality measures. Such quality indicators have been developed for neurosurgical procedures, collectively. We aimed to evaluate their applicability in patients that underwent surgery for vestibular schwannoma and to identify potential new disease-specific quality indicators.

Methods

One hundred and three patients operated due to vestibular schwannoma were subject to analysis. The primary outcomes of interest were 30-day and 90-day reoperation, readmission, mortality, nosocomial infection and surgical site infection (SSI) rates, postoperative cerebral spinal fluid (CSF) leak, facial, and hearing function. The secondary aim was the identification of prognostic factors for the mentioned primary outcomes.

Results

Thirty-day (90-days) outcomes in terms of reoperation were 10.7% (14.6%), readmission 9.7% (13.6%), mortality 1% (1%), nosocomial infection 5.8%, and SSI 1% (1%). A 30- versus 90-day outcome in terms of CSF leak were 6.8% vs. 10.7%, new facial nerve palsy 16.5% vs. 6.1%. Hearing impairment from serviceable to non-serviceable hearing was 6.8% at both 30- and 90-day outcome. The degree of tumor extension has a significant impact on reoperation (p < 0.001), infection (p = 0.015), postoperative hemorrhage (p < 0.001), and postoperative hearing loss (p = 0.026).

Conclusions

Our data demonstrate the importance of entity-specific quality measurements being applied even after 30 days. We identified the occurrence of a CSF leak within 90 days postoperatively, new persistent facial nerve palsy still present 90 days postoperatively, and persisting postoperative hearing impairment to non-serviceable hearing as potential new quality measurement variables for patients undergoing surgery for vestibular schwannoma.

Remnant Tumor Margin as Predictive Factor for Its Growth After Incomplete Resection of Cervical Dumbbell-Shaped Schwannomas

Objective

The purpose of our study was to investigate the risk factors of remnant tumor growth after incomplete resection (IR) of cervical dumbbell-shaped schwannomas (DS).

Methods

Twenty-one patients with IR of cervical DS with at least 2 years of follow-up were included and were divided into 2 groups: the remnant tumor growth (G) (n = 10) and no growth (NG) (n = 11) groups. The tumor location in the axial plane according to Toyama classification, the location of the remnant tumor margin, and the tumor growth rate (MIB-1 index) index were compared.

Results

No significant differences in Toyama classification and MIB-1 index were found. Age was significantly higher in the G group (61.4 years vs. 47.6 years; p=0.030), but univariate logistic regression analysis revealed little correlation to the growth (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.001–1.166; p=0.047). Seventeen patients (9 in the G and 8 in the NG group) underwent the posterior one-way approach, and significant differences in the location of the remnant tumor margin were confirmed: within the spinal canal in 1 and 0 case, at the entrance of the intervertebral foramen in 7 and 1 cases, and in the foramen distal from the entrance in 1 and 7 cases, in the G and NG groups, respectively (p=0.007). The proximal margin was identified as a significant predictor of the growth (OR, 56.0; 95% CI, 2.93–1,072; p=0.008).

Conclusion

Remnant tumors with margins distally away from the entrance of the foramen were less likely to grow after IR of cervical DS.

The behavior of residual tumors following incomplete surgical resection for vestibular schwannomas

The management of vestibular schwannoma (VS) with residual tumor following incomplete resection remains controversial and little is known regarding postoperative tumor volume changes. The behavior of residual tumors was analyzed for 111 patients who underwent surgery for newly diagnosed VS between September 2006 and July 2017. The postoperative tumor volume changes were assessed during a mean follow-up of 69 months (range 36–147 months). Fifty-three patients underwent imaging surveillance following incomplete resection. There was no residual tumor growth in 44 patients (83%). A significant regression of residual tumor volume was noted in the no growth group at postoperative 1 year (p = 0.028), 2 years (p = 0.012), but not from 3 years onwards. Significant predictors of regrowth were immediate postoperative tumor volume ≥ 0.7 cm³ (HR 10.5, p = 0.020) and residual tumor location other than the internal auditory canal (IAC) (HR 6.2, p = 0.026). The mean time to regrowth was 33 months (range 5–127 months). The 2-, 5-, and 10-year regrowth-free survival rates were 90.6%, 86.8%, and 83%, respectively. In conclusion, significant residual tumor regression could occur within 2 years for a VS with an immediate postoperative tumor volume less than 0.7 cm³ or residual tumor in IAC.

Gross-total versus near-total resection of large vestibular schwannomas. An institutional experience

OBJECTIVE

We will report our experience of the surgical treatment of large vestibular schwannomas (VSs).

PATIENTS, MATERIALS AND METHODS

We conducted a retrospective study of patients operated on for Koos grade IV VS between 2007 and 2015 at the Department of Neurosurgery, Emergency County Hospital, Târgu Mureş, Romania. We studied the general preoperatory clinical data, the preoperative and postoperative facial nerve status, preoperative hearing on the affected side, and any postoperative complications, including death.

RESULTS

Sixty-six cases were included in our study. The mean age was 52.95 years and 66.7% (n=44) of the sample were female. All patients had suffered from tinnitus and this had been followed by loss of serviceable hearing on the affected side in 89.4% (n=59) of cases. Preoperative facial palsy was found in 53% (n=35) of patients. The mean tumor size was 40.35 mm. Gross-total resection (GTR) was achieved in 24 (36.36%) cases, while near-total resection (NTR) was obtained in 42 (63.64%) cases. New-onset facial palsy or degradation of the preoperative facial deficit occurred in 12 (18.18%) cases, most of whom were patients with a GTR (n=9, 37.5%). This was statistically significant. There were no significant postoperative differences between the GTR and NTR groups. There was one death in the GTR group.

CONCLUSIONS

We conclude that near-total tumor removal provides good surgical results and better postsurgical quality of life for patients when compared to gross-total tumor resection. Therefore, this should be the end goal of the resection of large VSs.

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.

"Large and giant vestibular schwannomas: overall outcomes and the factors influencing facial nerve function"

(1) To study the overall outcomes of patients surgically treated for large/giant vestibular schwannomas (VSs) and (2) to identify and analyze preoperative and intraoperative prognostic factors influencing facial nerve (FN) outcome. A retrospective clinical study was conducted at a quaternary referral otology and skull-base center. A total of 389 cases were enrolled. The inclusion criteria were patients with tumor > 30 mm undergoing surgery with a minimum follow-up of 12 months. Neurofibromatosis-II, previous radiotherapy, revision surgeries, preoperative FN House-Brackmann (HB) grade > I, partial resections, incomplete records, or those lost to follow-up for a minimum period of 1 year were excluded. In addition, partial resections and cases where FN was sacrificed intraoperatively were also excluded and were analyzed separately. The mean duration of symptoms was 35.4 months, pronounced more in elderly (58.3 months) than in younger individuals (28.4 months). Mean tumor diameter was 36 mm and 52.7% was cystic. Total resection (TR), near total resection (NTR), and subtotal resections (STR) were achieved in 77.4%, 9.5%, and 13.2% of cases, respectively. Regrowth was observed only after STR (19.6%). Good (HB I-II), moderate (HB III), and poor (HB IV-VI) FN functions were observed in 36.8%, 51.7%, and 11.6% cases, respectively. Younger individuals underwent TR in 259 (86.9%) cases against 42 (46.2%) in elderly individuals. Non-total resections (NTR/STR) were performed in 49 (53.8%) cases in elderly as against 39(13.1%) in younger individuals. Good FN outcome was observed in 28 (57.1%) cases of non-total resections in elderly as against 13 (33.3%) cases in younger individuals. On multiple logistic regression analysis, size of the tumor, preoperatively prolonged duration of symptoms, profound deafness, and antero-superiorly located FN with respect to the tumor played a detrimental role in the final facial nerve outcome postoperatively. On the contrary, in large tumors (3-3.9 cm), presence of vertigo/disequilibrium had a relatively better impact on final FN outcome. Partial resections accounted for 41(7.8%) cases and FN was interrupted in 71(13.6%) cases in total. Factors detrimental to better FN outcome were giant VSs (> 4 cm), antero-superiorly located FN intratumorally, preoperatively prolonged duration of symptoms, and profound deafness. In large tumors (3-3.9 cm), presence of vertigo/disequilibrium had a better impact on FN outcome. Understandably, cases with TR in comparison with NTR/STR had worse FN outcomes. In comparison with younger patients, elderly patients underwent higher NTR/STR resulting in better FN outcomes. The above factors can be used as prognosticators for patient counseling and surgical decision making.

Vestibular Schwanomma: An Experience in a Developing World

Background

Tumors related to the acoustic nerves represent 90% of cerebellopontine angle diseases and have been in the picture for at least 200 years. Famous as acoustic neuromas and vestibular neuromas, these are usually benign, slow-growing tumors of Schwann cells of the myelin sheath. Surgery is the treatment of choice though some authors have suggested "wait and watch" policy. The aims of our study were to study the clinical presentation and management of the tumors, and to evaluate the perioperative outcomes of the surgery.

Methods

A retrospective review of the datasheet of 33 patients diagnosed with vestibular schwanomma who had undergone surgery from January 2014 to January 2017 was performed in National Academy of Medical Sciences, Bir Hospital, Kathmandu, Nepal. Analysis of the demographic data and perioperative outcomes was performed.

Results

Hearing loss was the main presenting symptom in 72% cases followed by tinnitus, dizziness, facial numbness and sudden sensorineural hearing loss. Mean tumur size was 39.7 ± 3 mm. The mean age of the patients was 46 ± 3 years with a female preponderance (1.2:1). In particular, the retrosigmoid route was preferred in all the cases since it was the most employed approach at our center and 63% of the tumors presented to us were grade 5. The surgical techniques allowed safe preservation of the facial function which was 93%. The hearing loss did not improve after the surgery in 94% while it worsened in 6% of cases. We did not find any significant relation between outcome and size, age, gender or laterality of the tumor (P > 0.05). There was no perioperative mortality.

Conclusions

The benign and slow-growing nature of vestibular schwanomma usually poses problems for the early diagnosis and treatment especially in a poor resource setting like ours. Likewise, there are very few studies so far done in the country regarding the incidence and management of the disease. Thus, this study might be helpful in providing insight into the occurrence of the disease in the present scenario and the need for much more studies in the future.

Clinical features, microsurgical treatment, and outcome of vestibular schwannoma with brainstem compression

Background:

Presenting symptoms, treatment considerations, and outcome are strongly related to the extension of vestibular schwannomas (VS). The aim of the current retrospective study was to analyze the clinical features, microsurgical treatment, and outcome of VS with brainstem compression.

Methods:

Forty-nine patients presented with VS (Hannover grading scale T4a or T4b) in our department. A subgroup analysis was performed among patients without (T4a) and with (T4b) compression and dislocation of the fourth ventricle.

Results:

Patients with type T4b VS presented significantly more often with long tract signs/ataxia (P < 0.05), tonsillar herniation (P < 0.001), and preoperative hydrocephalus (P < 0.01). No significant difference was found between the groups regarding hearing loss and facial nerve, trigeminal nerve, and lower cranial nerve function. Gross total resection was achieved in 83% of the cases, near total resection was achieved in 15% of the cases, and subtotal resection was performed in 2% of the cases. One patient died after massive postoperative bleeding caused by a coagulopathy. At last follow-up, 69% of the patients had excellent facial nerve function (Grade I–II) and the remaining 31% a fair outcome. Six patients (12%) required permanent ventriculoperitoneal shunting. Hearing was preserved in two patients. Forty-six patients (94%) were independent without occasional assistance (Karnofsky scale 70–100%).

Conclusions:

VS with brainstem compression is frequently associated with hydrocephalus, ataxia, long tract signs, multiple cranial nerve disorders, and occasionally, signs of intracranial hypertension. Primary microsurgical resection is an appropriate management option for large VS.

Facial Nerve Function and Quality of Resection in Large and Giant Vestibular Schwannomas Surgery Operated By Retrosigmoid Transmeatal Approach in Semi-sitting Position with Intraoperative Facial Nerve Monitoring

INTRODUCTION

Large and giant vestibular schwannomas pose a real problem in their management. The preservation of facial nerve function may limit tumor resection despite the use of intraoperative monitoring of the facial nerve. In Algeria, vestibular schwannomas represent 5% of all intracranial tumors operated on, 80.5% of which are large or giant.

METHODS

From January 2010 to December 2015, 151 large and giant vestibular schwannomas were operated in our department. Tumor diameter was between 30 and 60 mm. The most common presenting symptom was hearing loss, which was observed in 41.66% of all our patients. All patients were operated in the semi-sitting position with opening of the posterior wall of the internal auditory canal and under continuous intraoperative facial nerve function monitoring.

RESULTS

Tumor resection was total in 126 patients. Anatomic preservation of the facial nerve was the reason for nontotal resection in 25 patients. The facial nerve was anatomically preserved in 149 patients. Two years after surgery, the facial nerve function was grade I-II House-Brackmann (H-B) score in 124 cases (82%), grade III-IV H-B score in 21 cases (14%), and grade V-VI H-B score in 06 cases (04%). The status and the improvement of postoperative facial nerve function depend on 4 factors: anatomic preservation of nerve, stimulation threshold, cystic form, and the presence of train activity.

CONCLUSIONS

The development of anesthesia techniques and microsurgery and the systematic use of intraoperative monitoring of the facial nerve have allowed us to move from a life preservation era to another era of preservation of function.

Microsurgical management of vestibular schwannoma after failed previous surgery

OBJECTIVE Microsurgical treatment of recurrent vestibular schwannoma (VS) is difficult and poses specific challenges. The authors report their experience with 53 cases of surgically treated recurrent VS. Outcome of these tumors was compared to that of primarily operated on VS. Special attention was given to the facial nerve functional outcome. METHODS A retrospective analysis was performed of the patients who underwent surgery for recurrent VS at one institution from 2000 to 2013. The preoperative data, intraoperative findings, and outcome in terms of facial nerve function and improvement of the preoperative symptoms were analyzed and compared with those in a control group of 30 randomly selected patients with primarily operated on VS. A multivariate regression analysis was performed to test the factors that could affect the facial nerve outcome in each group. RESULTS Fifty-three consecutive patients underwent surgery for recurrent VS. Seventeen patients were previously operated on and received postoperative radiosurgery (Group A). Thirty-six patients were previously operated on but did not receive postoperative radiosurgery (Group B). The overall postoperative facial nerve function was significantly worse in Groups A and B in comparison with the control group (Group C). Interestingly, there was no significant difference in the facial nerve outcome among the 3 groups in patients who had good preoperative facial nerve function. The tumor size and the preoperative facial nerve function are variables that significantly affect the facial nerve outcome. Most of the patients showed improvement of the preoperative symptoms, such as trigeminal hypesthesia, gait disturbance, and headache. CONCLUSIONS Complete microsurgical tumor removal is the optimal management for patients with recurrent or regrowing VS. The procedure is safe, associated with favorable facial nerve outcome, and may also improve existing neurological symptoms.

Differences in clinical presentation, intraoperative findings and outcome between petroclival and lateral posterior pyramid meningioma

OBJECTIVE

The goal of this study was to determine the impact of the location of the most frequent skull base meningioma of the posterior fossa, i.e. petroclival (PCM) and lateral posterior pyramid meningioma (LPPM) on clinical presentation, surgical treatment and treatment results.

PATIENTS AND METHODS

We retrospectively reviewed a consecutive series of patients operated on for PCM (n=46) and LPPM (n=32). Uni- and multivariate analyses were performed to identify differences in clinical presentation, surgical treatment and pre-, intra- and postoperative factors of influence upon the outcome parameters: Complications rate, mortality, tumour recurrence/progress, hospital stay, Karnofsky Performance Score (KPS).

RESULTS

At Presentation, the rate of dizziness was higher in LPPM (56% vs. 7%, p<0,001) and trigeminal nerve impairment was more frequent in PCM (50% vs. 3%, p<0,001). Complete tumour resections were more often achieved (91% vs. 39%, p<0,001), and surgery lasted shorter (median: 247 min vs. 500 min, p<0,001) with less blood loss (median: 525 ml vs. 1000 ml, p<0,001) in LPPM compared to PCM. The overall complication rates (73% vs. 31%, p<0,001) as well the rate of irreversible complications (57% vs. 9%, p<0,004) were higher in PCM than in LPPM. The most frequent complications of PCM surgery were eye movement (46% vs. 6%, p<0,001), facial nerve (28% vs. 3%, p<0.02) and swallowing impairments (21% vs. 3%, p<0.02). The perioperative mortality was 11% in PCM and 0% in LPPM patients. In the multivariate analyses, KPS at discharge correlate positively with age (p=0.034) and preoperative KPS (p=0.0048) in LPPM and positively with staged resection (p=0.056) and negatively with the occurrence of surgical complications (p=0,0427) in PCM. Hospitalization time correlated with the blood loss (p<0,001) for PCM, negatively with the preoperative KPS (p=0.0002) for PCM and LPPM and positively with tumour diameter (p=0.0001) and non-surgical complications rate (p=0.0001) for LPPM.

CONCLUSION

As compared to LPPM, surgical treatment of PCM is associated with higher morbidity and mortality. The outcome of LPPM was primarily influenced by preoperative factors: Patients age, tumour size, preoperative KPS. The outcome of PCM was primarily influenced by intraoperative factors like: blood loss, surgery duration, staged tumour resection and the surgical complications rate.

Surgical treatment of vestibular schwannoma. Review of 420 cases

INTRODUCTION AND OBJECTIVES

Vestibular schwannoma is the most frequent cerebellopontine angle tumor. The aim of our study is to reflect our experience in the surgical treatment of this tumor

MATERIAL AND METHODS

Retrospective study of 420 vestibular schwannomas operated in our hospital between 1994-2014. We include tumor size, preoperative hearing, surgical approaches, definitive facial and hearing functional results, and complications due to surgery.

RESULTS

A total of 417 patients with 420 tumors were analyzed, 209 female (50.1%) and 208 male (49.9%). Mean age at diagnosis was 49.8±13.2 years. The majority of the tumors were resected through a translabyrinthine approach (80.2%). Total tumor removal was achieved in 411 tumors (98.3%), and anatomic preservation of facial nerve in 404 (96.2%). Definitive facial nerve outcome was House-Brackmann grade I and II in 69.9%, and was significantly better in tumors under 20mm. Surgical complications included cerebrospinal fluid leakage in 3 patients (0.7%) and retroauricular subcutaneous collection in 16 (3.8%), 5 cases of meningitis (1.2%), 4 patients with intracraneal bleeding (0.9%), and death in 3 patients (0.7%).

CONCLUSIONS

Surgery is the treatment of choice for vestibular schwannoma in the majority of patients. In our experience, the complication rate is very low and tumor size is the main factor influencing postoperative facial nerve function.

Staged resection for vestibular schwannoma

CONCLUSION

Surgery remains the preferred option for large vestibular schwannoma (VS). The presence of unpredictable intraoperative difficulties may convince the operator to suspend the surgery to avoid risks to patient life. Additional surgeries may be mandatory and are better performed using a transcochlear approach. High rates of complications, poor facial nerve results, and a percentage of incomplete removals should be expected in such unfavorable cases.

OBJECTIVES

To review the results for nine cases of huge VS treated by staged resection.

METHOD

A retrospective case review was performed for all nine patients who underwent staged resection of VS at the Gruppo Otologico between 1984-2012. The decision to perform staged surgery was always made intra-operatively after encountering unpredicted difficulties.

RESULTS

The nine patients represented 0.3% of all patients who underwent VS surgery during the same period. Mean tumor size was 4.7 cm (range = 3.0-6.6 cm). Two cases required three surgeries, resulting in a total of 20 operations. In addition, two cases required pre-operative ventriculoperitoneal shunt and one required temporary tracheotomy. After the final stage of surgery, complete removal had been achieved in six of the nine patients. The facial nerve was never preserved anatomically.

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.

The behavior of residual tumors and facial nerve outcomes after incomplete excision of vestibular schwannomas

OBJECT

The authors evaluated the behavior of residual tumors and facial nerve outcomes after incomplete excision of vestibular schwannomas (VSs).

METHODS

The case records of all patients who underwent surgical treatment of VSs were analyzed. All patients in whom an incomplete excision had been performed were analyzed. Incomplete excision was defined as near-total resection (NTR), subtotal resection (STR), and partial resection (PR). Tumors in the NTR and STR categories were followed up with a wait-and-rescan approach, whereas the tumors in the PR category were subjected to a second-stage surgery and were excluded from this series. All patients included in the study underwent baseline MRI at the 3rd and 12th postoperative months, and repeat imaging was subsequently performed every year for 7-10 years postoperatively or as indicated clinically. Preoperative and postoperative facial function was noted.

RESULTS

Of the 2368 patients who underwent surgery for VS, 111 patients who had incomplete excisions of VSs were included in the study. Of these patients, 73 (65.77%) had undergone NTR and 38 (34.23%) had undergone STR. Of the VSs, 62 (55.86%) were cystic and 44 (70.97%) of these cystic VSs underwent NTR. The residual tumor was left behind on the facial nerve alone in 62 patients (55.86%), on the facial nerve and vessels in 2 patients (1.80%), on the facial nerve and brainstem in 15 patients (13.51%), and on the brainstem alone in 25 patients (22.52%). In the 105 patients with normal preoperative facial nerve function, postoperative facial nerve function was House-Brackmann (HB) Grades I and II in 51 patients (48.57%), HB Grade III in 34 patients (32.38%), and HB Grades IV-VI in 20 patients (19.05%). Seven patients (6.3%) showed evidence of tumor regrowth on follow-up MRI. All 7 patients (100%) who showed evidence of tumor regrowth had undergone STR. No patient in the NTR group exhibited regrowth. The Kaplan-Meier plot demonstrated a 5-year tumor regrowth-free survival of 92%, with a mean disease-free interval of 140 months (95% CI 127-151 months). The follow-up period ranged from 12 to 156 months (mean 45.4 months).

CONCLUSIONS

The authors' report and review of the literature show that there is undoubtedly merit for NTR and STR for preservation of the facial nerve. On the basis of this they propose an algorithm for the management of incomplete VS excisions. Patients who undergo incomplete excisions must be subjected to follow-up MRI for a period of at least 7-10 years. When compared with STR, NTR via an enlarged translabyrinthine approach has shown to have a lower rate of regrowth of residual tumor, while having almost the same result in terms of facial nerve function.

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.

Outcome after translabyrinthine surgery for vestibular schwannomas: report on 1244 patients

The objective of this article is to study the outcome after translabyrinthine surgery for vestibular schwannomas, with special focus on the facial nerve function. The study design is a case series from a national centralized database and it is set in two University Hospitals in Denmark. Participants were 1244 patients who underwent translabyrinthine surgery during a period of 33 years from 1976 to 2009. Main outcome measures were tumor removal, intraoperative facial nerve preservation, complications, and postoperative facial nerve function. In 84% patients, the tumor was totally resected and in ~85% the nerve was intact during surgery. During 33 years, 12 patients died from complications to surgery and ~14% had cerebrospinal fluid leakage. Before surgery, 74 patients had facial paresis and 46% of these improved after surgery. In patients with normal facial function, overall ~70% had a good outcome (House-Brackmann grade 1 or 2). The chance of a good outcome was related to tumor size with a higher the chance the smaller the tumor, but not to the degree of tumor removal. In ~78% of the patients with facial paresis at discharge the paresis improved over time, in ~42% from a poor to a good function. The translabyrinthine approach is generally efficient in tumor control and with satisfactory facial nerve outcome. With larger tumors the risk of a poor outcome is evident and more data on patients managed with alternative strategies are warranted.

Facial nerve outcomes after surgery for large vestibular schwannomas: do surgical approach and extent of resection matter?

OBJECT

The object of this study was to evaluate facial nerve outcomes in the surgical treatment of large vestibular schwannomas (VSs; ≥ 2.5 cm maximal or extrameatal cerebellopontine angle diameter) based on both the operative approach and extent of tumor resection.

METHODS

A PubMed search was conducted of English language studies on the treatment of large VSs published from 1985 to 2011. Studies were then evaluated and included if they contained data regarding the size of the tumor, surgical approach, extent of resection, and postoperative facial nerve function.

RESULTS

Of the 536 studies initially screened, 59 full-text articles were assessed for eligibility, and 30 studies were included for analysis. A total of 1688 tumor resections were reported. Surgical approach was reported in 1390 patients and was significantly associated with facial nerve outcome (ϕ= 0.29, p < 0.0001). Good facial nerve outcomes (House-Brackmann Grade I or II) were produced in 62.5% of the 555 translabyrinthine approaches, 65.2% of the 601 retrosigmoid approaches, and 27.4% of the 234 extended translabyrinthine approaches. Facial nerve outcomes from translabyrinthine and retrosigmoid approaches were not significantly different from each other, but both showed significantly more good facial nerve outcomes, compared with the extended translabyrinthine approach (OR for translabyrinthine vs extended translabyrinthine = 4.43, 95% CI 3.17-6.19, p < 0.0001; OR for retrosigmoid vs extended translabyrinthine = 4.98, 95% CI 3.57-6.95, p < 0.0001). There were 471 patients for whom extent of resection was reported. There was a strong and significant association between degree of resection and outcome (ϕ= 0.38, p < 0.0001). Of the 80 patients receiving subtotal resections, 92.5% had good facial nerve outcomes, compared with 74.6% (n = 55) and 47.3% (n = 336) of those who received near-total resections and gross-total resections, respectively. In the 2-way comparison of good versus suboptimal/poor outcomes (House-Brackmann Grade III-VI), subtotal resection was significantly better than near-total resection (OR = 4.21, 95% CI 1.50-11.79; p = 0.004), and near-total resection was significantly better than gross-total resection (OR = 3.26, 95% CI 1.71-6.20; p = 0.0002) in producing better facial nerve outcomes.

CONCLUSIONS

In a pooled patient population from studies evaluating the treatment of large VSs, subtotal and near-total resections were shown to produce better facial nerve outcomes when compared with gross-total resections. The translabyrinthine and retrosigmoid surgical approaches are likely to result in similar rates of good facial nerve outcomes. Both of these approaches show better facial nerve outcomes when compared with the extended translabyrinthine approach, which is typically reserved for especially large tumors. The reported literature on treatment of large VSs is extremely heterogeneous and minimal consistency in reporting outcomes was observed.

Technical nuances of resection of giant (> 5 cm) vestibular schwannomas: pearls for success

Removal of vestibular schwannomas (VSs, or acoustic neuromas) remains one of the most challenging operations in neurosurgery. Giant or huge tumors (> 5 cm) heighten these challenges, and technical nuances play a special role in maximizing tumor resection while minimizing complications. In this article, the senior author describes his technical experience with microsurgical excision of giant VSs. The accompanying video further illustrates these details.

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.

Translabyrinthine approach: indications, techniques, and results

This article presents a comprehensive review of the translabyrinthine surgical approach for vestibular schwannoma. Additionally, it addresses the traditional labyrinthectomy and identifies a time-efficient version. Indications and outcomes of the approach are presented, along with detailed procedural technique from opening incision through closure. Complications and management of complications are discussed in detail, as well as postoperative patient care.

[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 removal of giant acoustic neuromas

OBJECTIVE

The authors present the outcome of radical surgical removal of giant acoustic neuromas.

METHODS

Twenty-nine patients with acoustic neuroma with maximum diameter greater than 40 mm, submitted to surgery between the years 2005 and 2010, were reviewed by a retrospective study. The extension of tumor removal, surgical morbidity, facial nerve function, hearing, and evolution after surgery of preoperative neurologic conditions were the studied parameters.

RESULTS

All tumors were completely removed by a retrosigmoid approach, without perioperative mortality. As complications related to the surgery, there were three cases of local cerebrospinal fluid leak, one case of nasal cerebrospinal fluid leak, two cases of meningitis, one pseudomeningocele, and one case of transient lower cranial nerve dysfunction. The anatomic integrity of the facial nerve was preserved in 86% and facial function in 72%. In the 21 patients who did not need hypoglossal-facial anastomosis (72%), facial function was excellent or good (HB I-II) in 13 cases (45%), fair (HB III) in 5 cases (17%), and poor (HB IV) in 3 cases (10%). Before surgery, 12 patients (41%) had useful (H2) or moderate (H3) hearing. In 7 of these 12 patients (58%), it was possible to preserve some hearing function (with moderate hearing), after surgical removal of the tumors. Six patients presented with radiologic signs of hydrocephalus, two of them with visual disturbances. Two patients presented with trigeminal neuralgia (one contralateral), three with facial sensory loss and one with swallowing problems, that disappeared after surgery.

CONCLUSIONS

Total removal of large acoustic neuroma can be achieved by retrosigmoid approach with acceptable morbidity and no mortality. Preoperative neurologic symptoms recovered after surgery in most cases. Facial function preservation was possible in the majority of cases. Even in large tumors, hearing preservation should be attempted if the patient has useful hearing preoperatively.

Facial nerve function after vestibular schwannoma surgery

OBJECT

The object of this study was to evaluate long-term postoperative facial nerve (FN) function in patients undergoing vestibular schwannoma (VS) surgery.

METHODS

The authors retrospectively reviewed the clinical course of patients affected by isolated VSs with normal preoperative FN function, with no previous surgical or radiotherapeutic treatment, and who underwent surgery between 1987 and 2007. Facial nerve function was clinically evaluated according to the House-Brackmann (HB) scale. The minimum postoperative follow-up was 12 months.

RESULTS

Among the 1550 patients surgically treated at the authors' center, 1151 matched inclusion criteria for the present study. The FN was anatomically interrupted in 48 cases (4.2%), and 51 patients (4.4%) underwent subtotal tumor removal and were considered separately. Among the 1052 patients with anatomically preserved FNs and total tumor removal, 684 (65%) enjoyed postoperative HB Grade I or II and 309 (29.4%) enjoyed Grade III, with the remaining 59 cases (5.6%) suffering unsatisfactory results (HB Grades IV-VI). As expected, FN function results deteriorated in cases of larger tumors.

CONCLUSIONS

The main factor influencing postoperative FN function was tumor size. Although there was a progressive deterioration in FN function outcome in relation to tumor size, a cutoff point between satisfactory and unsatisfactory results could be identified at around 2 cm in maximum extrameatal tumor diameter, with the "optimal size" for surgery identified at < 1 cm. This finding emphasizes the importance of an early diagnosis and should be kept in mind when selecting the correct timing for VS removal. For small lesions, the results following a middle cranial fossa approach were significantly worse as compared with those following the translabyrinthine and retrosigmoidretrolabyrinthine approaches.

Beyond audiofacial morbidity after vestibular schwannoma surgery

Object

Outcomes following vestibular schwannoma (VS) surgery have been extensively described; however, complication rates reported in the literature vary markedly. In addition, the majority of reports have focused on outcomes related to cranial nerves (CNs) VII and VIII. The objective of this study was to analyze reported morbidity unrelated to CNs VII and VIII following the resection of VS.

Methods

The authors performed a comprehensive search of the English language literature, identifying and aggregating morbidity and death data from patients who had undergone microsurgical removal of VSs. A subgroup analysis based on surgical approach and tumor size was performed to compare rates of CSF leakage, vascular injury, neurological deficit, and postoperative infection.

Results

One hundred articles met the inclusion criteria, providing data for 32,870 patients. The overall mortality rate was 0.2% (95% CI 0.1–0.3%). Twenty-two percent of patients (95% CI 21–23%) experienced at least 1 surgically attributable complication unrelated to CNs VII or VIII. Cerebrospinal fluid leakage occurred in 8.5% of patients (95% CI 6.9–10.0%). This rate was markedly increased with the translabyrinthine approach but was not affected by tumor size. Vascular complications, such as ischemic injury or hemorrhage, occurred in 1% of patients (95% CI 0.75–1.2%). Neurological complications occurred in 8.6% of cases (95% CI 7.9–9.3%) and were less likely with the resection of smaller tumors (p < 0.0001) and the use of the translabyrinthine approach (p < 0.0001). Infections occurred in 3.8% of cases (95% CI 3.4–4.3%), and 78% of these infections were meningitis.

Conclusions

This study provides statistically powerful data for practitioners to advise patients about the published risks of surgery for VS unrelated to compromised CNs VII and VIII.

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.

Surgical treatment of large vestibular schwannomas (stages III and IV)

OBJECTIVE

Study the results of surgical treatment of large vestibular schwannomas.

MATERIAL AND METHODS

Between January 1995 and December 2005, 87 stage III and IV unilateral vestibular schwannomas (Koos classification) were operated.

RESULTS

The approach used was for the most part translabyrinthine. Nine patients were operated in two phases. Tumor exeresis was total in 79% of the cases, nearly total in 17%, and subtotal in 3.6%. Good facial function was preserved in 63% of the patients. Mortality was zero. Tumor control after a mean follow-up of 45 months was 86%.

CONCLUSIONS

Surgery for large vestibular schwannomas should have a 0% mortality rate and low morbidity. Otoneurosurgical collaboration, with a preference for the translabyrinthine approach, with surgery undertaken in several phases if need be, provides maximum safety and good functional results as well as an acceptable residual tumor rate.

Diagnosis and therapy of vestibular schwannoma

MRI studies are of paramount importance for diagnosis and follow-up measurements during conservative and postinterventional management of vestibular schwannomas (VS). MRI findings that convey important information for hearing-preservation VS surgery are: length of tumor-cochlear nerve contact, involvement of the internal auditory canal, incomplete filling of internal auditory canal, tumor size less than 15 mm and the intralabyrinthine signal intensity on 3DFT-CISS gradient-echo images. Functional neuro-otologic studies of facial nerve function, hearing and vestibular/balance function provide a valuable means of assessment of the actual impairment of the functional status of the VS patient. Intraoperative monitoring of facial nerve function and hearing has been refined, resulting in improved final postoperative facial nerve and hearing outcomes in VS patients treated with microsurgery. Long-term results reported by teams practicing stereotactic radiosurgery or fractionated stereotactic radiotherapy have been very encouraging. On the other hand, conservative management appears to be a viable option for a select group of VS patients. The refinement of surgical technique has rendered surgery safer and less invasive, resulting in better functional outcomes. Steroid use is currently used postinterventionally to improve final hearing outcome, although with questionable effectiveness. Physical rehabilitation programs are applied to accelerate vestibular functional recovery postoperatively and there is weak evidence that early physical rehabilitation may improve the final facial nerve outcome. Quality-of-life measures have emerged as important determinants of final therapeutic decision-making. More studies with high levels of evidence are needed to support clinical decisions.

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.

Revision surgery for residual or recurrent vestibular schwannoma

OBJECTIVE

Assess the requirement for and describe the complication rates of revision surgery for vestibular schwannoma.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Patients undergoing surgery for vestibular schwannoma by the Manchester Neurotology Service between 1978 and 2004.

INTERVENTION

Surgery.

MAIN OUTCOME MEASURE(S)

The presence of recurrent or residual tumor; necessity for further treatment; complications from revision surgery.

RESULTS

Primary surgery was undertaken on 1,037 tumors, with 866 total (19 recurred), 128 near-total, and 43 subtotal removals. Further treatment was performed for 4 recurrent, 2 near-total, and 11 subtotal excised tumors. Thirty-five revision operations resulted in 14 total (1 recurred), 8 near-total, and 13 subtotal removals. Further treatment was required for 3 near-total and 6 subtotal excisions. Poor preoperative facial function (House-Brackmann Grades 4-6) was present in 9 of the 35 patients. A further 10 deteriorated by at least 3 grades by 1 year postoperatively. Other complications of revision surgery included 3 patients with cerebrospinal fluid leaks, a postoperative hematoma requiring evacuation, 2 cerebrovascular accidents, and 2 patients with new cranial nerve deficits.

CONCLUSION

Most residual tumors after primary surgery are successfully managed with watch and rescan. Tumor fragment size is the greatest determinant of revision treatment. After revision surgery, tumor regrowth is much less predictable. Revision surgery is usually considerably more difficult than primary surgery, with a higher complication rate, particularly with regard to the facial nerve. Changing the approach for revision surgery may confer an advantage to facial nerve function.

Facial nerve function after translabyrinthine vestibular schwannoma surgery

OBJECTIVES

To evaluate the long-term facial function of patients after translabyrinthine vestibular schwannoma [VS] surgery and identify factors that influence these outcomes.

STUDY DESIGN AND SETTING

A retrospective review was performed that included 580 consecutive patients who underwent translabyrinthine craniotomy for removal of VS at a tertiary referral neurotologic practice between February 2000 and July 2004. A total of 512 patients who underwent primary microsurgical treatment of sporadic unilateral VS met inclusion criteria. Patient and tumor characteristics as well as perioperative complications are described. Perioperative and long-term facial function were evaluated in 392 patients who had at least 1-year follow-up.

RESULTS

Complication rates after translabyrinthine craniotomy for VS are low. Patients with smaller tumors have significantly better postoperative facial function than those with larger tumors.

CONCLUSIONS

Excellent long-term facial function can be expected in the majority of patients who undergo microsurgical removal of VS via the translabyrinthine approach. Alternative treatment strategies may need to be developed for the treatment of VS > 3.5 cm in order to maximize postoperative facial function.

Controversies in building a management algorithm for vestibular schwannomas

PURPOSE OF REVIEW

The present review examines the various mainstream treatment options, benefits and risks, and controversies involved in developing a management algorithm for treatment of vestibular schwannoma.

RECENT FINDINGS

Advances in microsurgery and radiosurgery have made tremendous contributions to management of vestibular schwannoma; however, considerable controversy still exists. The auditory and facial nerve functional outcomes have improved with use of intraoperative monitoring for vestibular schwannoma removal and with lower radiosurgery doses; however, risks to the facial and auditory nerves still exist. Observing vestibular schwannomas for growth with serial magnetic resonance imaging is an increasingly popular option for small vestibular schwannomas that allows patients to enjoy hearing and facial function.

SUMMARY

The risks and benefits of each treatment option must be weighed for each patient, and management decisions regarding vestibular schwannomas should be individualized for each patient depending on tumor anatomy, patient preferences, and symptoms.

Acoustic Neuroma (Vestibular Schwannoma) Revision

The authors present their experience of more than 25 years, now in excess of 1200 patients, with cerebellopontine angle tumors. This article focuses on the management of planned subtotal resection of acoustic tumors in five subjects, and unexpected "residual" discovered by MRI scanning in 10 cases, which represents, to the best of the authors' knowledge, a residual rate of 1% of operated patients. The rate of residual tumor is as high as 19% in some series and, in part, depends on the surgical approach. For the purpose of this article, the authors did not include their cases of neurofibromatosis, because these tumors behave differently than unilateral sporadic schwannomas.