Conservative management of acoustic neuroma

The Influence of Modifiable Risk Factors on Postoperative Outcomes in Patients Receiving Surgery for Resection for Acoustic Neuroma

Acoustic neuromas are the most common tumor of the cerebellopontine angle that are associated with a number of symptoms that negatively impact a patient's quality of life. While the mainstay of treatment for these benign tumors remains microsurgical resection, there is limited research exploring how certain modifiable risk factors (MRFs) may affect the perioperative course. The purpose of this study was to investigate how MRFs including malnutrition, obesity, dyslipidemia, uncontrolled hypertension, and smoking may affect postoperative rates of readmission and nonroutine discharges. We utilized the 2016 and 2017 Healthcare Cost and Utilization Project Nationwide Readmissions Database. MRFs were queried using appropriate International Classification of Diseases, Tenth Revision (ICD-10) coding for categories including malnutrition, obesity, dyslipidemia, smoking, alcohol, and hypertension. The statistical analysis was done using RStudio (Version 1.3.959). Chi-squared tests were done to evaluate differences between categorical variables. The Mann-Whitney U-testing was utilized to evaluate for statistically significant differences in continuous data. The "Epitools" package was used to develop logistic regression models for postoperative complications and post hoc receiver operating characteristic curves were developed. Pertaining to nonroutine discharge, predictive models using malnutrition outperformed all other MRFs as well as those with no MRFs (P < .05). In the case of readmission, models using malnutrition outperformed those of obesity and smoking (P < .05). Again, an increase in predictive power is seen in models using dyslipidemia when compared to obesity, smoking, or uncontrolled hypertension. Lastly, models using no MRFs outperformed those of obesity, smoking, and uncontrolled hypertension (P < .05). This is the first study of its kind to evaluate the role of MRFs in those undergoing surgical resection of their acoustic neuroma. We concluded that certain MRFs may play a role in complicating a patient's perioperative surgical course.

Growth potential of small residual tumors after vestibular schwannoma surgery: comparison between remnants and the natural history of small tumors

OBJECTIVE

Due to the heterogeneous definitions of tumor regrowth and various tumor volume distributions, the nature of small remnants after vestibular schwannoma (VS) surgery and the appropriate timing of adjuvant stereotactic radiosurgery for these remnants remain unclear. In this study, the growth potential of small remnants (< 1 cm3) after VS surgery was compared with that of treatment-naïve (TN) small VSs.

METHODS

This retrospective single-center study included 44 patients with VS remnants following subtotal resection (STR) of a large VS (remnant group) and 75 patients with TN VS (< 1 cm3; TN group). A 20% change in tumor volume over the imaging interval indicated radiographic progression or regression. Tumor progression-free survival (TPFS) rates were estimated using the Kaplan-Meier method.

RESULTS

In the remnant group, the mean preoperative tumor volume was 13.8 ± 9.0 cm3 and the mean tumor resection rate was 95% ± 5%. The mean tumor volume at the start of the observation period did not differ significantly between the two groups (remnant vs TN: 0.41 ± 0.29 vs 0.34 ± 0.28 cm3, p = 0.171). The median periods until tumor progression was detected were 15.1 (range 4.9-76.2) months and 44.7 (range 12.6-93.2) months in the TN and remnant groups, respectively. In the remnant group, the TPFS rates were 74% and 70% at 3 and 5 years after the surgery, respectively, compared with 59% and 47% in the TN group. The log-rank test demonstrated a significant difference (p = 0.008) in the TPFS rates between the two groups. Furthermore, 42 patients each from the remnant and TN groups were matched based on tumor volume. TPFS was significantly longer in the remnant group than in the TN group (3-year rates, 77% vs 62%; 5-year rates, 73% vs 51%; p = 0.02). In the remnant group, 18% of the tumor remnants demonstrated regression during follow-up, compared with 9% in the TN group, but this intergroup difference was not significant (p = 0.25).

CONCLUSIONS

This study demonstrated that the growth potential of small VS remnants was lower than that of TN tumors. Observing for small remnants may be appropriate after STR of a large VS. Given the risk of tumor regrowth, careful observation using MRI should be mandatory during follow-up.

Vestibular Schwannomas

Vestibular Schwannomas are well treated by GKNS. This can be used alone for tumors up to 20cm³. For larger tumors subtotal, intracapsular resection followed by GKNS a few months later would seem to give the best results. While there remain disagreements relating to optimal treatment for VSs among colleagues using different techniques, there are indications that these are becoming less confrontational. The evidence in this chapter suggests that early GKNS intervention results in better hearing preservation and tumor control in small tumors. The evidence in favor of "wait and see" depends on series reporting on changes in tumor size using suboptimal measurements. It is more important to record the fate of hearing, and this would seem to be better preserved following early GKNS. The results of GKNS for NF2 are by no means as good as could be wished but would seem to be superior to those of microsurgery. The importance of screening of family members cannot be over emphasized.

Vestibular schwannomas with spontaneous shrinkage: about 35 cases

PURPOSES

The first aim is to describe the epidemiological, clinical, and radiological characteristics of regressive vestibular schwannomas (VS), based on volumetric measurements on MRI to define which regressions are significant. The secondary aim is to look for a correlation between a shrinkage of the tumor and the medical history, and the presence of clinical symptoms.

METHODS

We first selected all patients presenting with a VS who underwent two or more MRI of the internal auditory canal on the same 3 T MRI machine retrospectively between January 2013 and June 2018. All MRI images were evaluated independently by two radiologists. The volumetric analysis was performed contrast-enhanced 2D spin-echo T1-weighted sequence and expressed in cubic centimeters.

RESULTS

Thirty-five patients presented with a regressive VS on MRI (14%). The annual mean shrinkage rate was 0.08 cm³/year. Eighty percent of the patients present both a shrinkage by more than 0.01 cm³/year and a decrease of the initial tumor volume by more than 20%. The majority of patients are asymptomatic or presented moderate balance disorders, which remained stable or improved over time. Tinnitus was observed in 47% and was stable or improved in the majority of cases and the mean annual mean hearing loss was by < or = 4 dB/year.

CONCLUSION

Out of 247 VS, 14% decreased using follow-up (by > or = 2 MRI), and a spontaneous shrinkage greater than 0.01 cm³/year and greater than 20% could be considered significant.

Clinical Predictors of Facial Nerve Outcomes After Surgical Resection of Vestibular Schwannoma

OBJECTIVE

To identify clinical predictors of facial nerve (FN) outcomes after microsurgical resection of vestibular schwannoma (VS).

STUDY DESIGN

Prospective cohort study.

SETTING

Academic medical center.

METHODS

Consecutive patients undergoing VS resection from November 2017 to October 2019 were included. FN function was evaluated with the House-Brackmann (HB) scale and stratified into good (HB I-II) and poor (HB III-VI) function. Analyses included descriptive statistics, correlation, and logistic regression.

RESULTS

Of 256 patients who met criteria (mean age, 47.7 years; 62.5% female), 227 (88.7%) achieved good FN function postoperatively and 238 (93.0%) at latest follow-up (mean, 154.8 days). Operative approaches consisted of translabyrinthine (50.8%), retrosigmoid (25.0%), and middle fossa craniotomies (24.2%). Extent of resection was decided intraoperatively, and gross or near total resection was accomplished in 237 (92.6%) cases. Postoperative HB grade correlated with latest HB grade (0.615, P < .001). Factors associated with good postoperative FN function included small tumor size (≤15 mm; odds ratio [OR], 2.425; P = .042), gross or near total resection (OR, 3.170; P = .041), and ≥100-µV intraoperative FN electromyographic response to a 0.05-mA stimulus (OR, 22.242; P < .001). Factors associated with good FN function at latest follow-up included gross total resection (OR, 7.764; P = .003) and ≥100-µV FN electromyographic response (OR, 8.518; P < .001), accounting for surgical approach and tumor size.

CONCLUSION

Microsurgical resection of VS can be accomplished with excellent FN outcomes. Gross total resection and ≥100-µV intraoperative FN electromyographic response predicted excellent FN outcomes. Immediate postoperative FN function is a prognosticator of long-term FN function.

Initial Observation among Patients with Vestibular Schwannoma

Introduction  Vestibular schwannomas (VS) are slow growing tumors. Although there are a wide variety of available treatment options, these tumors are often initially observed. We aimed to establish the presenting symptoms and outcomes of patients treated with initial observation at our institution. Methods  The medical records of patients with radiographically diagnosed VS were reviewed from 1989 to 2018. Actuarial estimates of radiographic tumor control and freedom of local therapy were calculated and compared using Cox regression analyses. Results  A total of 360 patients were diagnosed with VS at our institution from 1989 through 2018 with a median age of 59.9 years. After radiographic diagnosis, 243 patients (67.5%) opted for initial observation. Local control at 1, 5, and 10 years was 91, 67, and 58%, respectively. On multivariable analysis, factors associated with shorter time to radiographic tumor progression included younger patient age ( p  = 0.016) and tumors with an extracanalicular component ( p  = 0.032). Regarding time until definitive treatment only larger baseline American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) tumor size predicted for earlier initiation of therapy ( p  < 0.001), although this was restricted to tumors with an extracanalicular component ( p  = 0.004), as opposed to purely internal auditory canal tumors ( p  = 0.839). Conclusion  Many patients who were initially observed continued to have satisfactory local control rates at 10 years. In patients with extracanalicular tumors, larger AAO-HNS tumor measurements were associated with earlier radiographic tumor progression and shorter time to local therapy, with 7 mm serving as a potential threshold value for extracanalicular tumors. Younger patients and tumors with primarily an extracanalicular portion may warrant closer observation.

What is the Required Frequency of MRI Scanning in the Wait and Scan Management?

The wait and scan policy is being increasingly used as the first measure after the diagnosis of a vestibular schwannoma (VS) using magnetic resonance imaging (MRI). As part of the European Academy of Otology and Neuro-Otology (EAONO) position statement on VS, the frequency of imaging has been studied in the literature. Among 163 studies, 29 fulfilled the inclusion criteria and were scored using the Grading of Recommendations, Assessment, Development, and Evaluation system. Because tumor growth rate during the first 5 years of follow-up is predictive of further growth during the upcoming years, a protocol for wait and scan is useful for centers dealing with this condition. The EAONO proposal is that after the initial diagnosis by MRI, a first new MRI would take place after 6 months, annually for 5 years, and then every other year for 4 years, followed by a lifelong MRI follow-up every 5 years. The first early MRI is to screen for fast-growing tumors, and the lifelong follow-up with tapered intervals is to detect late repeated growth.

Decision Making in the Wait-and-Scan Approach for Vestibular Schwannomas: Is There a Price to Pay in Terms of Hearing, Facial Nerve, and Overall Outcomes?

BACKGROUND

The wait-and-scan modality has emerged as an important strategy in the management of vestibular schwannoma (VS) as it has been demonstrated that many tumors grow slowly or do not show any growth over long periods.

OBJECTIVE

To analyze long-term outcomes of wait-and-scan in the treatment of patients with VS, discuss the factors contributing to the decision making, determine the inherent risks of the policy, and compare our results with literature.

METHODS

In total, 576 patients with sporadic unilateral VS who were managed with wait-and-scan were reviewed retrospectively. Of these, a subset of 154 patients with 5-yr follow-up was separately analyzed. The tumor characteristics including patterns of growth, rate of growth, hearing outcomes, and likely factors affecting the above parameters were analyzed.

RESULTS

The mean period of follow-up was 36.9 ± 30.2 mo. The mean age was 59.2 ± 11.6 yr. Thirteen different patterns of tumor growth were observed. Eighty-four (54.5%) of 154 tumors with 5-yr follow-up showed no growth throughout 5 yr. Fifty-six (36.4%) tumors showed mixed growth rates. Only 57 (37%) patients had serviceable hearing at the start of follow-up, but 32 (56.1%) maintained it at the end of follow-up. One hundred fifty (26%) of the 576 patients who failed wait-and-scan had to be taken up for surgery.

CONCLUSION

While there may be no price to pay in wait-and-scan as far as hearing is concerned, this may not be the case for facial nerve outcomes, wherein the results may be better if the patients are taken earlier for surgery.

Surgery of the lateral skull base: a 50-year endeavour

Disregarding the widely used division of skull base into anterior and lateral, since the skull base should be conceived as a single anatomic structure, it was to our convenience to group all those approaches that run from the antero-lateral, pure lateral and postero-lateral side of the skull base as “Surgery of the lateral skull base”. “50 years of endeavour” points to the great effort which has been made over the last decades, when more and more difficult surgeries were performed by reducing morbidity. The principle of lateral skull base surgery, “remove skull base bone to approach the base itself and the adjacent sites of the endo-esocranium”, was then combined with function preservation and with tailoring surgery to the pathology. The concept that histology dictates the extent of resection, balancing the intrinsic morbidity of each approach was the object of the first section of the present report. The main surgical approaches were described in the second section and were conceived not as a step-by-step description of technique, but as the highlighthening of the surgical principles. The third section was centered on open issues related to the tumor and its treatment. The topic of vestibular schwannoma was investigated with the current debate on observation, hearing preservation surgery, hearing rehabilitation, radiotherapy and the recent efforts to detect biological markers able to predict tumor growth. Jugular foramen paragangliomas were treated in the frame of radical or partial surgery, radiotherapy, partial “tailored” surgery and observation. Surgery on meningioma was debated from the point of view of the neurosurgeon and of the otologist. Endolymphatic sac tumors and malignant tumors of the external auditory canal were also treated, as well as chordomas, chondrosarcomas and petrous bone cholesteatomas. Finally, the fourth section focused on free-choice topics which were assigned to aknowledged experts. The aim of this work was attempting to report the state of the art of the lateral skull base surgery after 50 years of hard work and, above all, to raise questions on those issues which still need an answer, as to allow progress in knowledge through sharing of various experiences. At the end of the reading, if more doubts remain rather than certainties, the aim of this work will probably be achieved.

The changing landscape of vestibular schwannoma diagnosis and management: A cross-sectional study

OBJECTIVES

To assess the current state of the diagnosis and management of vestibular schwannoma (VS) as well as treatment trends, and to evaluate the role of treatment setting and various specialists in treatment plan.

METHODS

Patients diagnosed with VS completed a voluntary and anonymous survey. The questionnaires were distributed through Acoustic Neuroma Association website, Facebook page, and e-mail newsletters from January to March 2017.

RESULTS

In total, 789 VS patients completed the survey. Of those, 414 (52%) underwent surgery; 224 (28%) underwent radiotherapy; and 121 (15%) were observed. General otolaryngologists diagnosed 62% of responders, followed by primary care (11%) and neurotologists (10%). Patients who underwent surgery were significantly younger and had larger tumors compared to those treated with radiation or observation. The ratio of patients having nonsurgical versus surgical resection changed from 1:2 to 1:1 for the periods of 1979 through 2006 versus 2007 through 2017, respectively. Neurosurgeons (40%) and neurotologists (38%) were the most influential in treatment discussion. Neurotologists (P < 0.001) and general otolaryngologists (P = 0.04) were more influential than neurosurgeons for the decision process in patients with smaller tumors. Patients treated at academic versus nonacademic private institutions reported similar tumor sizes (P = 0.27), treatment decisions (P = 0.09), and decision satisfaction (P = 0.78).

CONCLUSION

There is a continuing trend toward nonsurgical management, with approximately half of the patients opting for nonsurgical management. In this cohort, the patients commonly presented with otologic symptoms and otolaryngologists made the most diagnoses. Neurotologists and neurosurgeons were the most influential in treatment discussion.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:482-486, 2020.

Risk Recall of Complications Associated with Vestibular Schwannoma Treatment

OBJECTIVE

To assess the risk recall of complications among patients who underwent different vestibular schwannoma (VS) treatments.

STUDY DESIGN

Patients with VS completed a voluntary and anonymous survey.

SETTING

Survey links were distributed via the Acoustic Neuroma Association (ANA) website, Facebook, and email list.

SUBJECTS AND METHODS

Surveys were distributed to ANA members from January to March 2017. Of the 3200 ANA members with a VS diagnosis at the time of survey distribution, 789 (25%) completed the survey.

RESULTS

Subjects reported the following incidence of posttreatment complications: imbalance (60%), hearing issues (51%), dry eyes (30%), headache (29%), and facial weakness (27%). Overall, 188 (25%) recalled remembering all the risks associated with their treatment. Among those in the surgical cohort (52%) who experienced balance issues, facial weakness, cerebrospinal fluid leak, meningitis, and stroke, 73%, 91%, 77%, 67%, and 33% claimed recall of these associated risks. Among those in the radiosurgery cohort (28%) who experienced balance issues, facial weakness, and hydrocephalus, 56%, 52%, and 60% recalled discussions of those risks. Patients with higher-level education (P = .026) and those who underwent surgery (P = .001) had a significantly higher risk recall ratio, while sex, age, and tumor size were not significant contributing factors.

CONCLUSION

Not all patients with VS who experienced treatment complications recalled remembering those risks being discussed with them. Patients with higher education and those who underwent surgery had a better recall of risks associated with different treatment modalities. The risk recall ratio of patients experiencing complications ranged 33% to 91%, suggesting an opportunity for decision-making and discussion improvement.

Middle Fossa Approach for Resection of Vestibular Schwannomas: A Decade of Experience

BACKGROUND

The middle cranial fossa (MCF) approach is a challenging surgical technique for the resection of small and intermediate sized, primarily intracanalicular, vestibular schwannomas (VS), with the goal of hearing preservation (HP).

OBJECTIVE

To describe a decade-long, single institutional experience with the MCF approach for resection of VS.

METHODS

This is a retrospective cohort study of 63 patients who underwent the MCF approach for resection of VS from 2006 to 2016. Audiometric data included pure-tone average (PTA), low-tone pure-tone average (LtPTA), word recognition score, and American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification at presentation and follow-up. Patients with postoperative serviceable (AAO-HNS class A-B) and/or useful (AAO-HNS class A-C) hearing were compared to those without HP. Facial nerve function was assessed using the House–Brackmann scale.

RESULTS

The mean age and duration of follow-up were 50 ± 13 yr and 21 ± 21 mo, respectively. The mean tumor size was 10 ± 4 mm. The serviceable and usable HP rates were 54% and 50%, respectively. Some residual hearing was preserved in 71% of patients. Large tumor size (P = .05), volume (P = .03), and extrameatal tumor extension (P = .03) were associated with poor audiometric outcomes. The presence of a fundal fluid cap (P = .01) was a favorable finding. At definitive testing, LtPTA was significantly better preserved than traditional PTA (P = .01). Facial nerve outcomes, tumor control rates, and durability of audiometric outcomes were excellent. 47% of patients pursued aural rehabilitation.

CONCLUSION

In our series, the MCF approach for VS provided excellent rates of tumor and facial nerve function, with durable serviceable HP.

Vestibular schwannomas: Accuracy of tumor volume estimated by ice cream cone formula using thin-sliced MR images

PURPOSE

We estimated the volume of vestibular schwannomas by an ice cream cone formula using thin-sliced magnetic resonance images (MRI) and compared the estimation accuracy among different estimating formulas and between different models.

METHODS

The study was approved by a local institutional review board. A total of 100 patients with vestibular schwannomas examined by MRI between January 2011 and November 2015 were enrolled retrospectively. Informed consent was waived. Volumes of vestibular schwannomas were estimated by cuboidal, ellipsoidal, and spherical formulas based on a one-component model, and cuboidal, ellipsoidal, Linskey's, and ice cream cone formulas based on a two-component model. The estimated volumes were compared to the volumes measured by planimetry. Intraobserver reproducibility and interobserver agreement was tested. Estimation error, including absolute percentage error (APE) and percentage error (PE), was calculated. Statistical analysis included intraclass correlation coefficient (ICC), linear regression analysis, one-way analysis of variance, and paired t-tests with P < 0.05 considered statistically significant.

RESULTS

Overall tumor size was 4.80 ± 6.8 mL (mean ±standard deviation). All ICCs were no less than 0.992, suggestive of high intraobserver reproducibility and high interobserver agreement. Cuboidal formulas significantly overestimated the tumor volume by a factor of 1.9 to 2.4 (P ≤ 0.001). The one-component ellipsoidal and spherical formulas overestimated the tumor volume with an APE of 20.3% and 29.2%, respectively. The two-component ice cream cone method, and ellipsoidal and Linskey's formulas significantly reduced the APE to 11.0%, 10.1%, and 12.5%, respectively (all P < 0.001).

CONCLUSION

The ice cream cone method and other two-component formulas including the ellipsoidal and Linskey's formulas allow for estimation of vestibular schwannoma volume more accurately than all one-component formulas.

Developing an algorithm for cost-effective, clinically judicious management of peripheral nerve tumors

Peripheral nerve tumors such as neurofibromas and schwannomas have become increasingly identified secondary to improved imaging modalities including magnetic resonance neurogram and ultrasound. Given that a majority of these peripheral nerve tumors are benign lesions, it becomes important to determine appropriate management of such asymptomatic masses. We propose a normal cost-effective management paradigm for asymptomatic peripheral nerve neurofibromas and schwannomas that has been paired with economic analyses. Specifically, our management paradigm identifies patients who would benefit from surgery for asymptomatic peripheral nerve tumors, while providing cost-effective recommendations regarding clinical exams and serial imaging for such patients.

Growth rate of vestibular schwannoma

Vestibular schwannoma (VS) is the most common tumor in the extra-axial posterior fossa compartment in adults. Growth rate is paramount to decision making regarding treatment and follow up of these tumors. We conducted a comprehensive review of the literature to answer four questions: What percentage of newly diagnosed VS will grow on follow-up? What factors correlate to tumor growth? What is the "normal" growth rate for sporadic VS? What factors characterize VS with rapid growth? Thirty-seven reports, with more than 4000 patients, fit our review criteria. One third of newly diagnosed VS will grow on follow-up of 1-3years. However, after 5years, up to one half will grow. Patient age and sex do not influence growth of VS. Hearing loss and vertigo at presentation do not predict tumor growth. It is unclear whether balance disturbance or tinnitus predict tumor growth. Tumor size and location do not predict tumor growth. Growth in the first year of observation is a strong predictor of tumor growth. The average growth rate of a VS is 0.99-1.11mm/year. However, the expected growth rate for VS that have been shown to grow at first follow-up is 3mm/year. Factors that may predict tumor growth of above 4mm/year are cystic and hemorrhagic features in the tumor, and hormonal treatment. VS grow at an average 1mm/year. VS that have been shown to grow at first follow-up should be considered for treatment, unless contraindicated. Long term follow-up is recommended for VS.

Spontaneous shrinkage of vestibular schwannoma

Background:

“Watch, wait, and rescan” (WWR) has an established place as a successful management option for a significant proportion of vestibular schwannomas (VS) as an alternative to microsurgical removal or stereotactic radiotherapy. VS may grow slowly and continuously, followed by stagnation or even shrinkage. We present two case reports of spontaneous shrinkage of VS along with a review of the literature.

Case Description:

A 29-year-old female presented with a progressive history of visual blurring and intermittent diplopia over 2 months. A 29 mm of maximum intracranial diameter (ICD) VS with secondary obstructive hydrocephalus was diagnosed. The patient underwent a ventriculo-peritoneal shunt with resolution of her symptoms and opted for initial WWR management. Interval scanning between 2007 and 2014 showed progressive reduction in the maximum ICD together with reduction in the degree of central tumor enhancement. Maximum ICD at most recent follow up was 22 mm. A 28-year-old female was referred with right sensorineural deafness. A right VS of maximum ICD of 27 mm was diagnosed. Initial WWR management was planned after discussion. Serial imaging showed an initial increase in the size of the tumor followed by progressive reduction in size. The most recent follow up showed a maximum ICD of 20 mm.

Conclusion:

Early WWR management can be associated with spontaneous shrinkage of VS over time. Prospective clinical study of larger numbers of such cases using the UK VS database may help to identify predictive factors for the spontaneous regression of VS.

Growth of Primary and Remnant Vestibular Schwannomas: A Three-Year Follow-Up Study

OBJECTIVE

Vestibular schwannomas (VSs) are benign, slowly growing tumors. The management strategy, however, remains unclear for both primary VS and remnant VS after subtotal or partial resection. In this study, we analyzed the radiographical tumor growth to elucidate factors possibly predicting growth or regrowth of their tumors.

METHODS

We retrospectively analyzed the data of 76 patients with diagnoses of VS at a single tertiary academic referral center. The primary VS group consisted of 43 patients with conservative management, and the remnant VS group included 33 patients with tumor remnant after surgery. All patients were followed up with serial magnetic resonance imaging without intervention. The primary end point in this study was significant tumor growth at the end of the 3-year follow-up period.

RESULTS

Multivariate analysis revealed that remnant VS was less likely to grow than primary VS (odds ratio: 0.27, 95% confidence interval: 0.09-0.84). Tumor volume was correlated with tumor growth; larger tumors grew more frequently than small tumors in both primary and remnant VS groups with marginal (P = 0.05) and definite (P = 0.007) significance, respectively. The receiver operating characteristic curves plotted for tumor growth identified the optimum cutoff points of tumor volumes with greater sensitivity and specificity for remnant VS than for primary VS (sensitivity: 80% vs. 59%, specificity: 87% vs. 76%, respectively).

CONCLUSIONS

Small remnant VS after surgery could be conservatively managed without additional treatment, and relatively large remnant VS should be followed up with close serial imaging or might be a possible candidate for radiosurgery during the early postoperative period.

Non surgical treatment of vestibular schwannoma

INTRODUCTION AND OBJECTIVES

To evaluate the results of local control and complications in the treatment of vestibular schwannoma treated with radiation.

METHODS

A retrospective study of 194 patients diagnosed with vestibular schwannoma, treated consecutively with radiation (either stereotactic radiosurgery or fractionated radiotherapy) from 1997 to 2012. We analyze the local control of tumors, as well as secondary complications to treatment with radiation.

RESULTS

A total of 132 (68%) tumors 68% are grade I-II tumors of the Koos classification, 40 (19%) are grade III, and 22 (13%) are grade IV. The tumors associated with neurofibromatosis (NF2), are 3.6% (6 tumors in 4 patients). The tumor control for the overall serie is 97% at 5 years, with a median follow-up of 80.4 months. For large tumors the local control is 91% at 5 years. Free survival of chronic complications is 89% at 5 years. Additionally, 50 tumors were subjected to regular follow-up with MRI without treatment, and 28 (58%) did not experienced tumor growth.

CONCLUSIONS

Radiation and follow up with MRI, are an alternative to surgery in the treatment of vestibular schwannoma, with a low level of complications inside of multidisciplinary approach.

Conservative management of vestibular schwannomas of 15 to 31 mm intracranial diameter

Objective:

To study the natural course of vestibular schwannomas 15 to 31 mm in diameter.

Methods:

A retrospective study of 45 patients conservatively managed with interval scanning was performed. Outcome measures were: changes in tumour size, clinical features and hearing. A tumour was considered to be growing if it increased in size by more than 2 mm.

Results:

Initial tumour sizes ranged from 15 to 31 mm, with a mean (± standard deviation) diameter of 20.1 ± 4.3 mm. The duration of follow up ranged from 6 months to 14 years (median, 3 years). Tumours grew in 11 cases (24.4 per cent), remained stable in 30 cases (66.7 per cent) and regressed in 4 cases (8.9 per cent). The overall mean tumour growth rate was 0.9 ± 2.2 mm per year; in growing tumours, it was 3.6 ± 2.9 mm per year.

Conclusion:

Outcomes were similar to those reported for smaller tumours. These findings suggest that patients with medium or moderately large tumours can be safely offered an initial period of conservative management before intervention is considered.

Spontaneous tumour shrinkage in 1261 observed patients with sporadic vestibular schwannoma

Objective:

To determine the rate of spontaneous tumour shrinkage in a group of patients with sporadic vestibular schwannoma managed with a ‘wait and scan’ approach.

Patients:

All patients with a unilateral cerebello-pontine angle tumour resembling a vestibular schwannoma were registered prospectively in a national database in Denmark. Patients registered with tumour shrinkage were identified and all computed tomography and magnetic resonance imaging scans retrieved, re-evaluated and related to the clinical data.

Results:

Of 1261 observed patients, 48 displayed spontaneous shrinkage (3.81 per cent). Mean absolute shrinkage was 6.25 mm, equivalent to 52.1 per cent. Absolute shrinkage correlated with tumour size and follow-up period, whereas relative shrinkage was significantly greater for tumours which were purely intrameatal at diagnosis. There was no correlation between age and the degree of shrinkage.

Conclusion:

Four per cent of sporadic vestibular schwannomas shrink spontaneously. These findings substantiate the ‘wait and scan’ strategy for tumours with a largest extrameatal diameter of up to 20 mm.

Salvage surgery of vestibular schwannoma after failed radiotherapy: the Gruppo Otologico experience and review of the literature

OBJECTIVES

The use of radiation therapy has largely widespread and becomes in many centers the preference modality of treatment for symptomatic patients who are old, medically unfit for surgical therapy, those who refuse surgery and in some recurrent or residual growing tumors. The risk of radiotherapy failure in the treatment of vestibular schwannoma might be underestimated in the literature. The purpose of this study is to show the Gruppo Otologico experience with salvage surgery to better understand the surgical outcomes and difficulties in treating vestibular schwannoma after failed radiotherapy.

STUDY DESIGN

Retrospective chart review of patients who required salvage surgery of vestibular schwannoma after failed radiotherapy.

SETTINGS

Quaternary referral otology and skull base center.

RESULTS

Between 1987 and 2010, 2500 cases of VS underwent surgical treatment at the Gruppo Otologico. Nineteen patients had received stereotactic radiation therapy before the surgical treatment. The interval time between radiotherapy and surgical salvage ranged from 1 to 10 years. In all the cases decision of surgery was taken following an increase in tumor size with or without new onset of symptoms. Complete tumor removal was achieved in 86.6% of the cases through a transotic, transcochlear or enlarged translabyrinthine approach with trans-apical extension. Difficult dissection of the tumor was encountered in 93.3% the cases. The facial nerve was anatomically preserved in 93.3% but its function was worsened in 73.3% of patients after at least 6 months of follow up. Malignant transformation of the vestibular schwannoma was encountered in one patient.

CONCLUSION

Complete surgical resection of VS is more difficult after radiotherapy with relatively poor facial nerve outcomes and nearly impossible hearing preservation. Patients who receive radiation therapy for the treatment of vestibular schwannoma should be made aware of its potential complications and risk of failure, especially in young patients and NF2 cases.

Decision-making of vestibular schwannoma patients

BACKGROUND

Patients suffering from vestibular schwannoma can choose between four modalities of management: (1) wait-and-scan, (2) tumour resection, (3) radiosurgery and (4) fractionated radiotherapy.

METHOD

This study is based on postal questionnaire survey of 739 vestibular schwannoma patients (survey response rate, 78%). It not only investigates the decision-making of patients, especially the medical consultation, but also further influences on the therapy decision and the patients' evaluation of possible side-effects of the treatment.

RESULTS

Only a minority of the patients was informed about radiosurgery and radiotherapy at all.

CONCLUSION

The praxis of patient counselling of acoustic neuroma patients in Germany is far from the ideal condition of medical consultation: The most important shortcoming is that it is unilateral: About 69% of the patients are informed about only one treatment option, generally surgery. Furthermore, information about side effects is usually insufficient. We recommend to advice all patients on all treatment options by an interdisciplinary team. The counselling should firstly be based on evidence-based medicine and secondly respond to the patients' individual life situation and preferences.

Acoustic neuroma growth: a systematic review of the evidence

AIM

To undertake a systematic review of the literature on acoustic neuroma growth. Predictors of growth were also explored.

MATERIALS AND METHODS

A comprehensive search was conducted to identify the relevant literature. The search yielded 2,455 papers. All titles were reviewed by 2 of the authors, and finally, 41 papers were found reporting data pertinent to growth.

RESULTS

The percentage of acoustic neuromas exhibiting growth ranges widely from 18 to 73%. The percentage of tumors reported not to grow for some years after diagnosis ranges from 9 to 75%. Some (usually less than 10%, but up to 22%) may get smaller. No reliable predictors of growth have been identified. The mean growth rate for all tumors varies between 1 and 2 mm/yr, and for only those that grow, between 2 and 4 mm/yr. However, there are cases with significant regression or exceptional growth (exceeding 18 mm/yr). There are various patterns of growth, and a tumor that shows growth may stop doing so and vice versa. Finally, some tumors that have been stable for many years can exhibit tumor growth.

CONCLUSION

The growth pattern of acoustic neuromas is variable and incompletely understood. As much as 75% of tumors have been reported to show no growth, supporting a "wait and rescan" policy in many patients, although there are no reliable predictors of tumor behavior, and some tumors may grow rapidly. Primary longitudinal studies are needed to better define the natural history and limit unnecessary interventions.

Spontaneous regression of vestibular schwannomas after resection of contralateral tumor in neurofibromatosis Type 2

The authors report on 2 patients with bilateral vestibular schwannomas (VSs) who underwent unilateral surgical tumor removal. One patient was followed up for 4 years, the other for 9; in both cases, the contralateral VS regressed markedly without any additional treatment during the follow-up period. Serial MR imaging was performed to monitor the untreated tumor, which in both cases involved the only hearing ear. The tumors were assessed volumetrically. The contralateral tumors appeared to enlarge mildly at initial follow-up and then, with no treatment, regressed (to 23% of the original maximum volume in Case 1 and to 15% of the original maximum in Case 2). The largest posterior fossa diameter decreased from 30.1 mm to 18.6 mm in Case 1 over 4 years and from 27 mm to 16 mm over 8 years in Case 2. Hearing declined only mildly during follow-up in both patients.

These cases demonstrate the first well-documented, long-term, spontaneous VS regressions in patients with neurofibromatosis Type 2. They underline the importance of careful observation of VS involving the only hearing ear in the management of bilateral VS to determine the natural growth pattern of the tumors. The mechanism of the dramatic spontaneous tumor regression is uncertain.

Evaluation of the vestibulo-ocular reflex using sinusoidal off-vertical axis rotation in patients with acoustic neurinoma

The vestibulo-ocular reflex (VOR) was studied to examine the utility of off-vertical axis rotation (OVAR) in the diagnosis of acoustic neurinoma. Subjects were sinusoidally rotated with eyes open in complete darkness at frequencies of 0.4 and 0.8 Hz with a maximum angular velocity of 60 degrees /s at either earth-vertical axis rotation (EVAR) or OVAR. Thirteen patients with acoustic neurinomas were investigated. Results showed that VOR gain during OVAR at 0.8 Hz and in a 30 degrees nose-up position in patients with internal auditory canal tumors was significantly less than the gain measured during EVAR. The VOR gain measured from all patients (including those with tumors extending to the cerebellopontine angle) was not significantly different when the patients were subjected to EVAR and OVAR. These observations were possibly due to superior vestibular nerve dysfunction. We concluded that certain stimulating parameters--patient's nose tilted up 30 degrees; sinusoidal OVAR at 0.8 Hz and 60 degrees /s maximum angular head velocity--were useful for evaluating vestibular function in patients suffering from an acoustic neurinoma located within the internal auditory canal.

Guiding patients through the choices for treating vestibular schwannomas: balancing options and ensuring informed consent. 2007

Counseling patients who are diagnosed with vestibular schwannomas, formerly known as acoustic neuromas, can be challenging. The health care provider has the responsibility to explain, in understandable language, to the patient or legal representative the proposed treatment options, risks and complications associated with each form of treatment, and alternatives to treatment, including no therapy. Patients should be encouraged to gather information before making a treatment decision. For the physicians managing these patients, information should be delivered in a balanced way to ensure patient understanding of their options leading to adequate informed consent.

Conservative versus primary surgical treatment of acoustic neuromas: a comparison of rates of facial nerve and hearing preservation

OBJECTIVES

To determine whether patients with small to medium sized acoustic neuromas managed conservatively suffer reduced rates of facial nerve and hearing preservation when compared with patients undergoing primary surgery.

DESIGN

An intention-to-treat comparison between patients managed conservatively at first presentation and those managed with primary surgery.

SETTING

Tertiary referral neurotological centre in Birmingham, UK.

PARTICIPANTS

Data were drawn from our database of 487 sporadic acoustic neuromas managed from 1997 to present day.

MAIN OUTCOME MEASURES

Facial nerve status (assessed using the House-Brackmann system) was collated for all conservatively managed patients (n = 167) and compared with that expected when calculated from primarily surgically managed tumours of equivalent size (n = 121). A chi-square test was employed to test the statistical significance of any difference. Hearing preservation (maintenance of AAO-HNS Class) in patients presenting with Class A or B hearing was compared between conservatively managed patients and those with primary surgical management.

RESULTS

Observed facial nerve preservation in conservatively managed patients was significantly better (P < 0.001) than expected when calculated from rates of facial nerve preservation in surgically managed patients. Hearing preservation was also significantly more successful in conservatively managed patients (Pearson chi-square: P < 0.000).

CONCLUSIONS

An initial period of conservative management is a safe and reasonable management policy in all acoustic neuromas up to 2 cm in size at the cerebello-pontine angle. Given that there are no failsafe ways of deciding potential for growth in acoustic neuromas, initial conservative management of these tumours offers superior hearing and facial nerve preservation when compared with primary surgical treatment.

Guiding patients through the choices for treating vestibular schwannomas: balancing options and ensuring informed consent

Counseling patients who are diagnosed with vestibular schwannomas, formerly known as acoustic neuromas, can be challenging. The health care provider has the responsibility to explain, in understandable language, to the patient or legal representative the proposed treatment options, risks and complications associated with each form of treatment, and alternatives to treatment, including no therapy. Patients should be encouraged to gather information before making a treatment decision. For the physicians managing these patients, information should be delivered in a balanced way to ensure patient understanding of their options leading to adequate informed consent.