Risk-benefit analysis of using the middle fossa approach for acoustic neuromas with >10 mm cerebellopontine angle component

Retrosigmoid versus middle fossa approach for hearing and facial nerve preservation in vestibular schwannoma surgery: A systematic review and comparative meta-analysis

BACKGROUND

Vestibular schwannomas (VS) are benign tumors arising from vestibular nerve's Schwann cells. Surgical resection via retrosigmoid (RS) or middle fossa (MF) is standard, but the optimal approach remains debated. This meta-analysis evaluated RS and MF approaches for VS management, emphasizing hearing preservation and Cranial nerve seven (CN VII) outcomes stratified by tumor size.

METHODS

Systematic searches across PubMed, Cochrane, Web of Science, and Embase identified relevant studies. Hearing and CN VII outcomes were gauged using the American Academy of Otolaryngology-Head and Neck Surgery, Gardner Robertson, and House-Brackmann scores.

RESULTS

Among 7228 patients, 56 % underwent RS and 44 % MF. For intracanalicular tumors, MF recorded 38 % hearing loss, compared to RS's 54 %. In small tumors (<1.5 cm), MF showed 41 % hearing loss, contrasting RS's lower 15 %. Medium-sized tumors (1.5 cm-2.9 cm) revealed 68 % hearing loss in MF and 55 % in RS. Large tumors (>3cm) were only reported in RS with a hearing loss rate of 62 %.

CONCLUSION

Conclusively, while MF may be preferable for intracanalicular tumors, RS demonstrated superior hearing preservation for small to medium-sized tumors. This research underlines the significance of stratified outcomes by tumor size, guiding surgical decisions and enhancing patient outcomes.

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

Factors associated with hearing outcomes after a middle fossa approach in 131 consecutive patients with vestibular schwannomas

OBJECTIVE

The middle fossa approach is an effective option for the treatment of small (Koos grade I and II) vestibular schwannomas (VSs) when the goal is hearing preservation. The authors evaluated the rates of hearing preservation and examined the factors associated with improved hearing outcomes after the middle fossa approach for VSs.

METHODS

In this retrospective, single-center cohort study evaluating the clinical outcomes after resection of small VSs using the middle fossa approach, consecutive adult patients (> 18 years) who underwent surgery between January 2000 and December 2021 were included. Clinical and imaging characteristics were analyzed, including baseline hearing status, duration of surgery, anesthetic parameters, and imaging characteristics of the surgically treated tumors.

RESULTS

Among the 131 included patients, 102 had valid and discoverable pre- and postoperative audiology assessments. The mean follow-up was 26 months (range 1-180 months). There were 85 patients with serviceable hearing preoperatively, defined as American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) class A or B, of whom 78% retained class A or B hearing at the last follow-up. Binary logistic regression demonstrated that preoperative hearing AAO-HNS class (OR 0.19, 95% CI 0.05-0.77; p = 0.02), overlap between fundus and cochlea (OR 0.32, 95% CI 0.11-0.96; p = 0.04), and duration of anesthesia (OR 0.98, 95% CI 0.97-0.99; p = 0.03) were independent predictors of hearing outcomes. Additionally, 75% of patients with high diffusion-weighted imaging signal in the tumor (p = 0.009) and 67% of patients with the tumor originating at the modiolus of the cochlea (p = 0.004) had poor hearing outcomes.

CONCLUSIONS

The hearing preservation rates after microsurgical resection of small VSs using the middle fossa approach are high, with 78% of patients maintaining AAO-HNS class A or B hearing. Poor hearing status at baseline, longer duration of anesthesia, and large overlap between the fundus of the internal auditory canal and the cochlea were independently associated with unfavorable hearing outcomes. Imaging characteristics can be used to stratify patients' risk of hearing loss.

Auditory Brain Stem Response Predictors of Hearing Outcomes after Middle Fossa Resection of Vestibular Schwannomas

Objectives To analyze the relationship between preoperative and intraoperative auditory brain stem response (ABR) characteristics and hearing outcomes in patients with vestibular schwannomas (VS) undergoing hearing preservation (HP) surgery via a middle cranial fossa (MCF) approach.

Design Prospective study.

Setting Academic tertiary skull base referral center.

Methods Pre- and postoperative pure-tone average (PTA) and word recognition score (WRS) were examined. Intraoperative ABR wave III latency, wave V latency, and amplitude were recorded. HP was defined as postoperative WRS ≥50%.

Participants Adult patients with VS and WRS ≥50% who underwent MCF tumor resection between November 2017 and September 2019.

Main Outcome Measures Postoperative hearing outcomes.

Results Sixty patients were included. Mean tumor size was 9.2 mm (range, 3–17). HP rates were 56.7% for the cohort and 69.7% for tumors <10 mm. A complete loss of wave V was associated with an 82.9% increase in postoperative PTA (p < 0.001) and 97.2% decrease in WRS (p < 0.001), whereas a diminished wave V was correlated with 62.7% increase in PTA (p < 0.001) and 55.7% decrease in WRS (p = 0.006). A diminished or absent wave V, but not increased wave III/V latency or decreased wave V amplitude, was correlated with a decline in postoperative hearing class (r = 0.735, p < 0.001). Receiver-operating characteristic analysis demonstrated that a stable wave V has the highest accuracy in predicting HP (sensitivity of 82.6%, specificity of 84.8%).

Conclusion Of the examined preoperative and intraoperative ABR characteristics, a stable wave V intraoperatively was the strongest predictor of HP after MCF resection of VS.

Level of Evidence Level III.

Total Facial Paralysis after Vestibular Schwannoma Surgery: Probability of Regaining Normal Function

The aim of the present study was to ascertain the precise fraction of vestibular schwannoma cases that recover to normal function after postoperative total facial nerve paralysis and to compare our results with those presented in the literature. This was a retrospective case review of 631 cases. Among the 132 cases with immediate postoperative facial nerve palsy (House Brackmann [HB] grade VI), only 2 (1.5%) recovered to normal function (HB grade I). In an attempt to compare our results with those of other series in the literature, we found a large variation in the incidence of recovery of this group of patients to grade I, ranging from 0% to 50%. Our analysis of the reported data revealed widely varying methods of data collection and presentation, making a scientifically valid comparison particularly difficult. According to our data, complete (HB grade I) or near-complete (HB grade II) facial nerve function recovery from an immediate postoperative grade VI palsy is extremely rare.

Hearing Preservation Surgery in Vestibular Schwannoma: The Hidden Truth

To compare the results of hearing preservation surgeries using different approaches — the enlarged middle cranial fossa approach and the retrosigmoid approach — and different classification systems, stressing the importance of preserving “normal hearing,” we performed a retrospective case review in a tertiary care medical center. The charts of 107 patients with vestibular schwannoma who underwent tumor resection were reviewed. Hearing preservation was reported according to 2 different classification systems: the modified Sanna classification and the classification of the American Academy of Otolaryngology—Head and Neck Surgery. The facial nerve results were graded according to the House-Brackmann scale. The hearing preservation rates differed markedly depending on the classification used. We conclude that hearing preservation in acoustic neuroma is a more difficult proposition than most surgeons appreciate, especially in terms of serviceable hearing.

Is the middle fossa approach the treatment of choice for intracanalicular vestibular schwannoma?

OBJECTIVES:

To compare the 2 surgical techniques most commonly used during vestibular schwannoma (VS) surgery, i.e., the middle fossa (MF) and the retrosigmoid-transmeatal (RS-TM) routes, when hearing preservation is attempted.

STUDY DESIGN:

A longitudinal study of a series of consecutive patients operated on with the 2 techniques by the same surgeon was conducted. Selection criteria included tumor confined to the internal auditory canal (IAC) with a length ranging from 4 to 12 mm and hearing class A or B. Patients were alternately assigned to 1 of the 2 groups regardless of auditory class and distance of the tumor from the IAC fundus. Thirty-five subjects were operated on with the RS-TM technique and 35 via the MF route.

RESULTS:

No significant differences in auditory and facial nerve function results between the 2 techniques were observed. The RS-TM approach, however, showed better facial nerve results at discharge. VS size, IAC enlargement, and, particularly, the distance from the IAC fundus were found to influence the postoperative results more than the type of approach itself.

CONCLUSIONS:

The MF approach has been described as being the better technique for VS surgery in terms of auditory results. However, this claim lacks statistical substantiation because no prospective studies are to be found in the literature. The present longitudinal investigation shows that the MF approach does not afford any particular advantages over the RS-TM route in terms of auditory results in intracanalicular VS, with the exception of tumors reaching the IAC fundus.

Facial Nerve Outcomes in Middle Cranial Fossa vs Translabyrinthine Approaches

OBJECTIVE: To compare the final facial nerve outcomes between middle cranial fossa (MCF) vs translabyrinthine (TL) resection of size-matched vestibular schwannomas.

STUDY DESIGN AND SETTING: Retrospective case review at a tertiary care hospital. All patients who underwent resection utilizing either MCF or TL approaches with tumors 18 mm or smaller and complete data were included in the analysis. One hundred twenty-four patients were identified meeting the above criteria, with sixty-three in the translabyrinthine group and sixty-one in the middle fossa group. One-week-postoperative and final facial nerve examinations were compared in the two surgical groups. Patients were separately analyzed in subgroups: tumors smaller than 10 mm and those that were between 10 and 18 mm.

RESULTS: The tumor size range for the MCF group was 3-18 mm while it was 4-18 mm for the TL group. No statistically significant difference was found in facial nerve outcomes between the two surgical groups, at the first postoperative visit week and at last follow-up.

CONCLUSION: Facial nerve outcomes are similar using TL and MCF approaches for resection of vestibular schwannomas up to 18 mm in size.

SIGNIFICANCE: Patients undergoing the MCF approach for hearing preservation can be counseled that there is no increased risk of permanent facial nerve weakness, compared to the TL approach.

EBM RATING: B-3

Retrosigmoid removal of small acoustic neuroma: curative tumor removal with preservation of function

Object

Management of small acoustic neuromas (ANs) consists of 3 options: observation with imaging follow-up, radiosurgery, and/or tumor removal. The authors report the long-term outcomes and preservation of function after retrosigmoid tumor removal in 44 patients and clarify the management paradigm for small ANs.

Methods

A total of 44 consecutively enrolled patients with small ANs and preserved hearing underwent retrosigmoid tumor removal in an attempt to preserve hearing and facial function by use of intraoperative auditory monitoring of auditory brainstem responses (ABRs) and cochlear nerve compound action potentials (CNAPs). All patients were younger than 70 years of age, had a small AN (purely intracanalicular/cerebellopontine angle tumor ≤ 15 mm), and had serviceable hearing preoperatively. According to the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology–Head and Neck Surgery Foundation, preoperative hearing levels of the 44 patients were as follows: Class A, 19 patients; Class B, 17; and Class C, 8. The surgical technique for curative tumor removal with preservation of hearing and facial function included sharp dissection and debulking of the tumor, reconstruction of the internal auditory canal, and wide removal of internal auditory canal dura.

Results

For all patients, tumors were totally removed without incidence of facial palsy, death, or other complications. Total tumor removal was confirmed by the first postoperative Gd-enhanced MRI performed 12 months after surgery. Postoperative hearing levels were Class A, 5 patients; Class B, 21; Class C, 11; and Class D, 7. Postoperatively, serviceable (Class A, B, or C) and useful (Class A or B) levels of hearing were preserved for 84% and 72% of patients, respectively. Better preoperative hearing resulted in higher rates of postoperative hearing preservation (p = 0.01); preservation rates were 95% among patients with preoperative Class A hearing, 88% among Class B, and 50% among Class C. Reliable monitoring was more frequently provided by CNAPs than by ABRs (66% vs 32%, p < 0.01), and consistently reliable auditory monitoring was significantly associated with better rates of preservation of useful hearing. Long-term follow-up by MRI with Gd administration (81 ± 43 months [range 5–181 months]; median 7 years) showed no tumor recurrence, and although the preserved hearing declined minimally over the long-term postoperative follow-up period (from 39 ± 15 dB to 45 ± 11 dB in 5.1 ± 3.1 years), 80% of useful hearing and 100% of serviceable hearing remained at the same level.

Conclusions

As a result of a surgical technique that involved sharp dissection and internal auditory canal reconstruction with intraoperative auditory monitoring, retrosigmoid removal of small ANs can lead to successful curative tumor removal without long-term recurrence and with excellent functional outcome. Thus, the authors suggest that tumor removal should be the first-line management strategy for younger patients with small ANs and preserved hearing.

Surgery of the ear and the lateral skull base: pitfalls and complications

Surgery of the ear and the lateral skull base is a fascinating, yet challenging field in otorhinolaryngology. A thorough knowledge of the associated complications and pitfalls is indispensable for the surgeon, not only to provide the best possible care to his patients, but also to further improve his surgical skills. Following a summary about general aspects in pre-, intra-and postoperative care of patients with disorders of the ear/lateral skull base, this article covers the most common pitfalls and complications in stapes surgery, cochlear implantation and surgery of vestibular schwannomas and jugulotympanal paragangliomas. Based on these exemplary procedures, basic "dos and don'ts" of skull base surgery are explained, which the reader can easily transfer to other disorders. Special emphasis is laid on functional aspects, such as hearing, balance and facial nerve function. Furthermore, the topics of infection, bleeding, skull base defects, quality of life and indication for revision surgery are discussed. An open communication about complications and pitfalls in ear/lateral skull base surgery among surgeons is a prerequisite for the further advancement of this fascinating field in ENT surgery. This article is meant to be a contribution to this process.

Determining benchmarks in hearing preservation surgery for vestibular schwannoma

Objectives The objectives of this study were to determine minimal benchmarks of success in vestibular schwannoma hearing preservation surgery, wherein the likelihood of having preserved hearing in a single patient is at least as likely as having created a poor facial nerve outcome for a single patient. Design This is a statistical analysis of published literature. Setting Academic Tertiary Medical Center. Main Outcome Measures Based on published natural history data, the number needed to treat (NNT) equation was used to calculate the minimally acceptable hearing preservation rates within various hearing classification schemes. Results Given good facial nerve outcome rates of 85, 90, and 95%, the corresponding hearing preservation rates at 4.7 years that are likely to preserve classes A and B hearing (American Academy of Otolaryngology-Head and Neck Surgery classification) in a single patient as to cause a poor facial nerve outcome are 70, 65, and 60%, respectively. If surgery is limited exclusively to intracanalicular tumors, these rates drop to 62, 57, and 52%, respectively. If the word recognition scoring classification is used, required hearing preservation rates are higher. Conclusion It is possible to use the NNT equation alongside projected facial nerve outcomes to estimate benchmarks of minimally acceptable hearing preservation rates.

Hearing preservation surgery for vestibular schwannoma: experience with the middle fossa approach

OBJECT

In the early 1960s William F. House developed the middle fossa approach for the removal of small vestibular schwannomas (VSs) with the preservation of hearing. It is the best approach for tumors that extend laterally to the fundus of the internal auditory canal, although it does have the potential disadvantage of increased facial nerve manipulation, especially for tumors arising from the inferior vestibular nerve. The aim of this study was to monitor the hearing preservation and facial nerve outcomes of this approach.

METHODS

A prospective database was constructed, and data were retrospectively reviewed.

RESULTS

Between December 2004 and January 2012, 30 patients with small VSs underwent surgery via a middle fossa approach for hearing preservation. The patients consisted of 13 men and 17 women with a mean age of 46 years. Tumor size ranged from 7 to 19 mm. Gross-total resection was accomplished in 25 of 30 patients. Preoperative hearing was American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) Class A in 21 patients, Class B in 5, Class C in 3, and undocumented in 1. Postoperatively, hearing was graded as AAO-HNS Class A in 15 patients, Class B in 7, Class C in 1, Class D in 2, and undocumented in 5. Facial nerve function was House-Brackmann (HB) Grade I in all patients preoperatively. Postoperatively, facial nerve function was HB Grade I in 28 patients, Grade III in 1, and Grade IV in 1. There were 3 complications: CSF leakage in 1 patient, superficial wound infection in 1, and extradural hematoma (asymptomatic) in 1. The overall hearing preservation rate of at least 73% and HB Grade I facial nerve outcome of 93% in this cohort are in keeping with other contemporary reports.

CONCLUSIONS

The middle fossa approach for the resection of small VSs with hearing preservation is a viable and relatively safe option. It should be considered among the various options available for the management of small, growing VSs.

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

Object

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

Methods

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

Results

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

Conclusions

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

Middle fossa approach: indications, technique, and results

This article discusses the indications, surgical technique, results, and complications of middle fossa craniotomy (MFC) for vestibular schwannoma surgery, focusing on issues such as serviceable hearing, tumor characteristics, and patient-specific factors that help determine options for therapy. MFC is suitable for intracanalicular vestibular schwannomas that extend less than 1 cm into the cerebellopontine angle in patients with good hearing. With the expanding use of modern imaging, many small tumors are being identified in patients with no or minimal symptoms. Patients with these tumors have three therapy options: (1) stereotactic radiotherapy, (2) microsurgery, and (3) observation (ie, wait-and-scan approach).

Analysis of hearing preservation and facial nerve function for patients undergoing vestibular schwannoma surgery: the middle cranial fossa approach versus the retrosigmoid approach--personal experience and literature review

OBJECTIVE

To compare hearing preservation and facial nerve function outcomes in patients undergoing vestibular schwannoma surgery performed using either the middle cranial fossa approach (MCFA) or the retrosigmoid approach (RSA).

MATERIALS AND METHODS

A review of the medical records of patients diagnosed with vestibular schwannoma who underwent surgical tumor removal in a single reference center via the MCFA or the RSA between January 1988 and December 2008 was conducted.

RESULTS

During this period, 90 patients underwent surgery via the MCFA while 86 patients received surgical treatment via the RSA. Of the patients subjected to the MCFA, 80.7% were characterized by a House-Brackmann (HB) grade I or II outcome, whereas 96.5% of patients undergoing the RSA were characterized by a HB grade I or II outcome (p = 0.001). This difference appeared only for extrameatal tumors when we compared size-matched tumors (58.3% MCFA vs. 98% RSA; p = 0.0006). There was no statistically significant difference in the hearing outcomes upon consideration of hearing preservation as characterized by the modified Sanna classification system involving classes A and B (18.9% MCFA vs. 10.6% RSA; p = 0.122).

CONCLUSION

No statistically significant difference in hearing preservation was identified when comparing tumors operated upon via the MCFA versus the RSA. However, our results indicate that a higher risk of facial nerve function impairment exists if the surgery is performed via the MCFA under circumstances where the tumor extends to the cerebellopontine angle.

Change in hearing and tinnitus in conservatively managed vestibular schwannomas

OBJECTIVES

The aim of this study was to evaluate the change of hearing and tinnitus in a group of conservatively managed unilateral vestibular schwannomas (VS).

DESIGN

Retrospective case series review.

SETTING

Tertiary referral otoneurological and skull base surgery department.

PARTICIPANTS

Seventy patients affected by unilateral VS with at least two audiograms available were retrospectively evaluated.

MAIN OUTCOME MEASURES

Changes in pure tone average (PTA), speech discrimination score (SDS), and tinnitus were analyzed.

RESULTS

At diagnosis 16 patients (22.9%) had a PTA of 0 to 30 dB and 38 (54.4%) a PTA of 0 to 50 dB. At the end of the follow-up period, 9 patients (12.9%) had a PTA of 0 to 30 dB and 27 (38.7%) had a PTA of 0 to 50 dB, representing a hearing preservation rate of 56% and 70%, respectively. Of patients with both tonal and speech audiometry, 71.4% with class A hearing (PTA < 30 dB/SDS > 70%) maintained their initial hearing and 60% with class A or B hearing (PTA < 50 dB/SDS > 50%) maintained this useful hearing. Forty-two patients (60%) did not show a significant growth in their tumor over the period of observation. In this group of patients the mean PTA after a mean follow-up time of 40 months decreased from 44 dB HL to 50.8 dB HL, with a yearly rate of 2.47 dB HL. The chance of maintaining a PTA of 0 to 30 dB in this group of patients was 57.1% and a PTA of 0 to 50 dB was 81.4%.

CONCLUSIONS

In this group of patients affected by VS and managed conservatively with a mean follow-up of 33.3 months, the risk of losing eligibility for hearing preservation surgery was lower than 30%.

[Extended middle fossa approach in treatment of vestibular schwannoma--technique of surgery and postoperative complications]

INTRODUCTION

The main tumor of cerebellopontine angle are vestibular schwannoma (80-90%). According to National Institute of Health Consensus Development Conference the best treatment method is microsurgery. There are three principal surgical approaches: translabyrinthin, retrosigmoid and middle fossa. Only the latter two approaches provide the possibility of hearing preservation.

AIM

Technique of surgery and postoperative morbidity after MFA.

MATERIAL AND METHODS

39 patients (40 tumor) suffered from tumor of cerebellopontine angle, operated by using middle fossa approach in years 1998-2007. We evaluate hearing preservation and function of facial nerve and others postoperative morbidity.

RESULTS

22.5% of patients has hearing impairment and 32.5% has facial weakness. By individual cases we observed: CSF leak, meningitis, corneal ulceration, ischialgia, wound bleeding and venue thrombosis. 1/3 of patients suffered from headache and disequilibrium and 1/6 suffered from tinnitus.

CONCLUSION

According to NIH middle fossa approach is one of three possible approaches in microsurgery of cerebellopontine angle tumors. There is possible total tumor removal with hearing preservation. Monitoring of facial and cochlear nerve during operation is recommended.

Mapping clinical outcomes expectations to treatment decisions: an application to vestibular schwannoma management

OBJECTIVE

Complex medical decision making obligates tradeoff assessments among treatment outcomes expectations, but an accessible tool to perform the necessary analysis is conspicuously absent. We aimed to demonstrate methodology and feasibility of adapting conjoint analysis for mapping clinical outcomes expectations to treatment decisions in vestibular schwannoma (VS) management.

STUDY DESIGN

Prospective.

SETTINGS

Tertiary medical center and US-based otologists/neurotologists.

SUBJECTS

Treatment preference profiles among VS stakeholders-61 younger and 74 older prospective patients, 61 observation patients, and 60 surgeons-were assessed for the synthetic VS case scenario of a 10-mm tumor in association with useful hearing and normal facial function.

MAIN OUTCOME MEASURE

Treatment attribute utility.

METHODS

Conjoint analysis attribute levels were set in accordance to the results of a meta-analysis. Forty-five case series were disaggregated to formulate microsurgery facial nerve and hearing preservation outcomes expectations models. Attribute utilities were computed and mapped to the realistic treatment choices of translabyrinthine craniotomy, middle fossa craniotomy, and gamma knife radiosurgery.

RESULTS

Among the treatment attributes of likelihoods of causing deafness, temporary facial weakness for 2 months, and incurable cancer within 20 years, and recovery time, permanent deafness was less important to tumor surgeons, and temporary facial weakness was more important to tumor surgeons and observation patients (Wilcoxon rank-sum, p < 0.001). Inverse mapping of preference profiles to realistic treatment choices showed all study cohorts were inclined to choose gamma knife radiosurgery.

CONCLUSION

Mapping clinical outcomes expectations to treatment decisions for a synthetic clinical scenario revealed inhomogeneous drivers of choice selection among study cohorts. Medical decision engines that analyze personal preferences of outcomes expectations for VS and many other diseases may be developed to promote shared decision making among health care stakeholders and transparency in the informed consent process.

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.

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.

Influence of nerve branch of origin and extracanalicular extension of the tumor on hearing after middle fossa removal of vestibular schwannoma

CONCLUSION

Neither nerve branch of origin nor extracanalicular (up to 1 cm) extension of a vestibular schwannoma (VS) influence the postoperative hearing outcome in patients operated via a middle cranial fossa (MCF) approach.

OBJECTIVE

To test whether the nerve branch of tumor origin and an extracanalicular, up to 1 cm, tumor extension influences hearing outcome after MCF VS surgery.

PATIENTS AND METHODS

This was a retrospective case review of 50 patients with postoperative pure-tone audiogram (PTA) performed later than 90 days after surgery. Twenty patients had a superior vestibular nerve (SVN) tumor and 27 patients had an inferior vestibular nerve (IVN) tumor. In three patients the nerve branch of origin of the VS could not be unequivocally determined. Thirty-four patients had a purely intracanalicular (IC) tumor and 16 patients had an extracanalicular extension in the cerebello-pontine angle. The differences between preoperative and postoperative air-conduction pure-tone hearing thresholds at 500, 1000, 2000, 3000, and 4000 Hz were compared between groups using the Mann-Whitney-Wilcoxon test.

RESULTS

Neither vestibular nerve branch of origin nor extracanalicular tumor extension (up to 1 cm) caused any significant difference in the degree of postoperative hearing change at any of the tested PTA frequencies.

Lesions of the petrous apex: diagnosis and management

Management of petrous apex pathology poses a unique challenge even to the most seasoned skull base surgeons. The central location in the skull base with adjacent critical neurovascular structures makes access to this region more than a trivial matter. Significant advances in diagnostic imaging have greatly facilitated the diagnosis of petrous apex lesions. The introduction of modern skull base surgery techniques also has provided skull base surgeons with numerous avenues to the petrous apex while significantly decreasing morbidity. The latest diagnostic and management strategies are discussed and an update of some of the more common pathologic entities is provided.

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.

[Predictive factors of facial palsy of the acoustic neurinoma after retrosigmoid surgery: 230 cases]

OBJECTIVES

To determine predictive factors influencing postoperative facial palsy during retro sigmoid approach in vestibular schwannoma surgery.

MATERIAL AND METHODS

Retrospective study over 230 patients with vestibular schwannoma, mostly stade I and II, operated by retro sigmoid approach, by the same oto neuro chirurgical team between 1993 and 2004. Pre and post operative parameters taken into consideration: quantitative: age and sex, audiometric parameters, duration of clinical symptoms; qualitative: tumor anatomic factors and facial nerve function according to House Brackmann classification.

RESULTS

8 days after surgery, 92% of patients have a normal or subnormal facial nerve function, 5% a facial paresis and 3% a paralysis. After one year, only 4% of patients still have a grade III to VI paralysis. Latency of vertigo with facial nerve paralysis is 4.33 vs. 1.97 year in absence of paralysis. Hearing conservation is 85% without facial nerve paralysis vs. 58% with facial nerve paralysis; Wave III latency (PEAP) with facial nerve paralysis is 4.54 vs. 4.28 ms if not.

CONCLUSION

Significant predictive factors of facial nerve palsy outcome are: age, post surgery hearing conservation, wave III latency, difficulty in tumor dissection, vertigo latency.

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.

Vestibular schwannoma management: What is the 'best' option?

There is an abundance of medical literature describing the management options for vestibular schwannomas. However, the lack of high quality clinical trials means that, for any individual patient, the decision is often based on the clinician's personal biases. The management options that are available are conservative treatment, surgery, single-dose stereotactic radiosurgery and fractionated radiotherapy. In this review, we set out what the aims of managing a vestibular schwannoma should be and compare how these different treatment modalities perform. The particular objectives of tumour control, cranial nerve preservation, prevention of malignancy, quality of life and cost-effectiveness are discussed. It remains difficult to differentiate between these methods when more than one is suitable; the literature confirms that they are all safe and effective, but the decision must be the patient's, based on their individual priorities. This review should equip the clinician to provide an informed overview of the options.

Counseling Patients on Surgical Options for Treating Acoustic Neuroma

The selection of surgical approach for the removal of AN is a complex one, depending on factors related to specific tumor anatomy, patient characteristics, and the familiarity and skill level of the skull base team.Overall, the literature supports that surgical outcomes are acceptable in regard to tumor removal, patient safety, and complication rates. The inconsistent reporting methods in the current literature make it difficult to assess logically the rates for hearing preservation, facial nerve outcome, and complications as controlled for tumor size and other preoperative patient characteristics. The best conclusions would be from prospective surgical trials controlling for patient factors, size of the tumor, and experience of the skull base team. In the absence of such studies, formal meta-analyses may help clarify specific differences among approaches.

Quality of life after unilateral acoustic neuroma surgery via middle cranial fossa approach

CONCLUSIONS

Patients with acoustic neuroma experienced reduced quality of life (QOL) after surgery. Individual factors did not have a significant effect on QOL. In the future, QOL should be a basic factor in the outcome evaluation of different therapeutic regimens in the treatment of acoustic neuroma.

OBJECTIVE

To measure the QOL of patients who underwent unilateral acoustic neuroma surgery via the middle cranial fossa approach.

MATERIAL AND METHODS

The Short Form-36 (SF-36) Health Survey and a self-designed disease-specific questionnaire were used during follow-up examinations to assess health-related QOL. The pure-tone average was used to specify hearing ability. Facial nerve function was described using the House-Brackmann grading system. A total of 28 male and 14 female patients who underwent surgery between 1997 and 2001 were included in the study.

RESULTS

Patients' QOL scores revealed significant reductions in QOL in comparison to normative German QOL data. Gender, age, tumor size or location and clinical symptoms such as hearing loss and restricted facial nerve function did not have an effect on QOL. The SF-36 scales physical functioning, role functioning-physical, bodily pain, general health, social functioning and role functioning-emotional demonstrated significant QOL reductions.

Long-term hearing preservation after surgery for vestibular schwannoma

Object. Vestibular schwannomas (VSs) are now amenable to resection with excellent hearing preservation rates. It remains unclear whether immediately postoperative hearing is a durable result and will not diminish over time. The aim of this study was to determine the rate of long-term preservation of functional hearing following surgery for a VS and to examine factors influencing hearing preservation.

Methods. All patients eligible for hearing preservation (Gardner—Robertson Class I or II) who had undergone resection of a VS by a single surgeon were reviewed retrospectively. Follow-up audiograms and magnetic resonance images were obtained.

Of 142 patients deemed eligible for hearing preservation surgery, 38 had immediate postoperative hearing confirmed by an audiogram. In these patients with preserved hearing, the audiographic results demonstrated functional hearing in 30 (85.7%) of 35 patients who underwent repeated testing at a mean follow-up time of 7 years. Delayed hearing loss occurred in five (14.3%) of the 35 patients and did not correlate significantly with the size of the tumor. Hearing improved one Gardner—Robertson class postoperatively in three (7.9%) of the 38 patients.

Conclusions. Long-term functional hearing was maintained in 85.7% of patients when it was preserved immediately postoperatively and the result was independent of tumor size. The results of this study emphasize that long-term preservation of functional hearing is a realistic goal following VS surgery and should be attempted in all patients in whom preoperative hearing is determined to be Gardner—Robertson Class I or II.

A Comparison of Direct Eighth Nerve Monitoring and Auditory Brainstem Response in Hearing Preservation Surgery for Vestibular Schwannoma

OBJECTIVE

The objective of this study was to compare the effectiveness of direct eighth nerve monitoring (DENM) and auditory brainstem response (ABR) in facilitating hearing preservation during vestibular schwannoma resection.

STUDY DESIGN

This was a retrospective study.

SETTING

: Tertiary referral center.

METHODS

We conducted a retrospective clinical study of the use of ABR and DENM during vestibular schwannoma removal. Tumors were removed through a retrosigmoid craniotomy. The rate of hearing preservation between the two monitoring modalities was compared. The additional outcome measures of facial nerve function and cerebral spinal fluid leak rate were also evaluated.

RESULTS

Hearing preservation was attempted in 77 patients with vestibular schwannomas. Tumor sizes ranged from 0.5 cm to 2.5 cm. Hearing was preserved in 71% of patients with tumors 1 cm or less and in 32% of patients with tumors between 1 and 2.5 cm when direct eighth nerve monitoring was used. Hearing preservation rates with ABR for tumors 1 cm or less were 41% and 10% in patients with tumors between 1 and 2.5 cm (p=0.03) Facial nerve preservations rates were 94% (House-Brackmann 1-2) for tumors less than 2 cm.

CONCLUSIONS

DENM provides significantly higher rates of hearing preservation during vestibular schwannoma resection when compared with ABR.

Chronic Pachymeningitis Presenting as Asymmetric Sensorineural Hearing Loss

OBJECTIVE

The objective of this study was to characterize the auditory dysfunction associated with chronic pachymeningitis (inflammation of the dura mater).

STUDY DESIGN AND SETTING

We conducted a university-based retrospective review.

RESULTS

Three patients were identified who were diagnosed with chronic pachymeningitis after being referred for asymmetric sensorineural hearing loss. All patients were found to have other neurologic symptoms and signs during careful neurotologic evaluation. Two varieties of chronic pachymeningitis exist: a hypertrophic mass lesion and a linear dural thickening. Although the hypertrophic variety could be easily detectable by noncontrast magnetic resonance imaging (MRI), the linear form is only visible with the use of gadolinium enhancement.

CONCLUSION

Chronic pachymeningitis is a rare form of sensorineural hearing loss that could portend an underlying disease of greater concern. Extensive evaluation is needed to exclude identifiable causes of chronic pachymeningitis, including infectious, neoplastic, and autoimmune diseases.

SIGNIFICANCE

The clinician should be aware that the evaluation of a patient with asymmetric sensorineural hearing loss involves more than simply ruling out an acoustic neuroma. Fast-spin echo MRI techniques without the use of gadolinium contrast could miss a number of potentially treatable diseases such as chronic pachymeningitis. Patients with asymmetric sensorineural hearing loss should be carefully evaluated for other neurologic findings, and imaging with enhanced MRI is recommended.

Middle fossa versus retrosigmoid-transmeatal approach in vestibular schwannoma surgery: a prospective study

OBJECTIVE

To compare the advantages, disadvantages, and results obtained with the middle fossa and retrosigmoid-transmeatal approaches during pure intracanalar vestibular schwannoma surgery in an attempt to preserve hearing.

STUDY DESIGN

Prospective study of patients treated from 1998 to 2001.

SETTING

Tertiary care referral center.

PATIENTS

Patients with intracanalar vestibular schwannoma (size ranging from 4 to 12 mm), 25 operated on with the retrosigmoid-transmeatal technique and 25 via the middle fossa route.

MAIN OUTCOME MEASURES

Facial nerve and auditory function were examined at 1 year with both techniques. Auditory results were also evaluated as a function of tumor size, distance from the internal auditory canal fundus, and internal auditory canal enlargement.

RESULTS

The results indicated no significant difference in facial nerve and auditory function results between the two techniques. The retrosigmoid-transmeatal approach, however, yielded better facial nerve function results at discharge. Postoperative hearing was better when the distance from the fundus was greater than 3 mm, when the size of the vestibular schwannoma was equal to or less than 7 mm, and when the internal auditory canal enlargement was less than 3 mm.

CONCLUSIONS

The middle fossa approach does not afford any particular advantages over the retrosigmoid-transmeatal approach in terms of auditory results. Facial nerve function is less satisfactory in the short term, when the middle fossa route is used, but can be improved by decompression and gentle displacement of the facial nerve in its labyrinthine portion.

Is it worthwhile to attempt hearing preservation in larger acoustic neuromas?

OBJECTIVE

To determine the hearing outcome in patients undergoing surgery via the retrosigmoid approach for acoustic neuromas with a substantial component in the cerebellopontine angle.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

The medical records of all patients undergoing acoustic neuroma removal via the retrosigmoid approach at a tertiary referral center were retrospectively reviewed. Sixty-four patients with both cerebellopontine angle component >or=15 mm and preoperative audiometry of class A or B (American Academy of Otolaryngology-Head and Neck Surgery) were identified.

MAIN OUTCOME MEASURES

Postoperative average pure tone threshold and word recognition scores, categorized according to the classification of the American Academy of Otolaryngology-Head and Neck Surgery, were used to assess hearing outcome.

RESULTS

Overall, only 6.3% (4 of 63) retained good hearing (class A or B) postoperatively. Hearing preservation rate in the smallest (15- to 19-mm) group was 17.6% (3 of 17), which was better than that for the larger groups. No successful hearing preservation was achieved in tumors with >or=25 mm cerebellopontine angle component (0 of 23).

CONCLUSIONS

Surgeon and patient alike would always choose a hearing preservation technique if there was no potential for increased morbidity in making the attempt. When compared with the non-hearing preservation translabyrinthine approach, the retrosigmoid approach had a higher incidence of persistent headache. In addition, efforts to conserve the auditory nerve prolong operating time, increase the incidence of postoperative vestibular dysfunction, and carry a slightly higher risk of tumor recurrence. Nevertheless, even though the probability of success is disappointingly small, when excellent hearing is present we favor offering the option of a hearing conservation attempt when the patient has been well informed of the pros and cons of the endeavor. Factors weighing against undertaking this effort include larger cerebellopontine angle component (>or=25 mm), deep involvement of the fundus, wide erosion of the porus, and marginal residual hearing.

The effect of age on acoustic neuroma surgery outcomes

OBJECTIVES

To ascertain the effect of age on hearing preservation, facial nerve outcome, and complication rates after acoustic neuroma surgery.

STUDY DESIGN

Retrospective chart review. Two study arms were used: a comparison of the authors' oldest patients with their youngest patients (extremes of age arm) and an analysis of all middle fossa surgical procedures (middle fossa arm).

SETTING

Tertiary referral center

PATIENTS

Total of 329 patients. For the extremes of age arm, 205 patients were studied in two cohorts with 150 older patients (>60 years) compared with 55 younger patients (<40 years). The approaches included 21 middle fossa (MF), 38 retrosigmoid (RS), and 91 translabyrinthine (TL) procedures in the older group versus 25 MF, 17 RS, and 13 TL in the younger. For the middle fossa arm, there were 170 patients (age range 15-76 years) who underwent the MF approach for an attempt at hearing preservation.

MAIN OUTCOME MEASURES

Hearing preservation was defined as the maintenance of either class A or class B hearing (AAO-HNS class). Good facial nerve outcome was considered the maintenance of either grade 1 or 2 (House-Brackmann scale). Cerebrospinal fluid leak rates and other postoperative complications were also tabulated.

RESULTS

After adjustment for tumor size and surgical approach using multiple logistic regression analysis, the extremes of age study arm demonstrated that there is a lower chance of preserving good hearing in older patients (p = 0.048, odds ratio = 0.30). Age was not associated with a difference in the rate of good facial nerve outcome (p = 0.2). There was a trend toward slightly higher rates of cerebrospinal fluid leak in the older patient group (p = 0.07) but no difference in the rate of other complications (p = 0.9). The middle fossa study arm, after adjustment for tumor size and surgical approach, demonstrated that older patient age is associated with a lower rate of preservation of good hearing (p = 0.01, O.R.=1.044). There was no association between age and good facial outcome (p = 0.7).

CONCLUSIONS

Older patient age lowers the chance of hearing preservation but does not affect facial outcomes. There is a trend toward a higher rate of cerebrospinal fluid leak in older patients, but no increased risk of other complications.