Management of Facial Nerve Schwannoma in Patients With Favorable Facial Function

Surgery versus radiosurgery for facial nerve schwannoma: a systematic review and meta-analysis of facial nerve function, postoperative complications, and progression

OBJECTIVE

Intracranial facial nerve schwannomas (FNS) requiring treatment are frequently recommended for surgery or stereotactic radiosurgery (SRS). The objective of this study was to compare facial nerve function outcomes between these two interventions for FNS via a systematic review and meta-analysis.

METHODS

A search of the Ovid EMBASE, PubMed, SCOPUS, and Cochrane databases from inception to July 2019 was conducted following PRISMA guidelines. Articles were screened against prespecified criteria. Facial nerve outcomes were classified as improved, stabilized, or worsened by last follow-up. Incidence was pooled by random-effects meta-analysis of proportions.

RESULTS

Thirty-three articles with a pooled cohort of 519 patients with FNS satisfied all criteria. Twenty-five articles described operative outcomes in 407 (78%) patients; 10 articles reported SRS outcomes in 112 (22%). In the surgical cohort, facial nerve function improved in 23% (95% CI 15%-32%), stabilized in 41% (95% CI 32%-50%), and worsened in 30% (95% CI 21%-40%). In the SRS cohort, facial nerve function was improved in 20% (95% CI 9%-34%), stable in 66% (95% CI 54%-78%), and worsened in 9% (95% CI 3%-16%). Compared with SRS, microsurgery was associated with a significantly lower incidence of stable facial nerve function (p < 0.01) and a significantly higher incidence of worsened facial nerve function (p < 0.01). Tumor progression and complication rates were comparable. Outcome certainty assessments were very low to moderate for all parameters.

CONCLUSIONS

Unfavorable facial nerve function outcomes are associated with surgical treatment of intracranial FNS, whereas stable facial nerve function outcomes are associated with SRS. Therefore, SRS should be recommended to patients with FNS who require treatment, and surgery should be reserved for patients with another indication, such as decompression of the brainstem. Further study is required to definitively optimize and validate management strategies for these rare skull base tumors.

Facial Nerve Schwannoma Extending to Jugular Foramen: A Case Report

Facial nerve schwannoma (FNS) is a benign, slow-growing schwannoma that originates from Schwann cells. Facial nerve schwannoma is the most common tumor of the facial nerve but rare and only accounts for 0.15% to 0.8% of intracranial neurinomas. It may be manifested as asymmetric hearing loss, facial palsy, and hemifacial spasm. A 56-year-old woman was transferred to our department, because of pain behind the right ear and spasm of the right lateral muscle for more than 2 years and pulsatile tinnitus for half a year. Based on the preoperative medical history, physical signs, and auxiliary examination, it was diagnosed with jugular foramen (JF) space-occupying lesion. We removed the tumor through the infratemporal fossa type A approach and found that the tumor originated from the facial nerve. After the tumor resection, sural nerve transplantation was performed. The patient demonstrated postoperative facial palsy (House-Brackman grade VI) and was smoothly discharged after good recovery. Facial nerve schwannoma rarely invades the JF, and the most common tumor in the JF is the glomus jugular tumor, followed by the posterior cranial schwannoma. They have common symptoms, making it difficult to obtain a correct diagnosis. Clinical data, medical history, and auxiliary examinations should be carefully analyzed to avoid misdiagnosis or mistreatment. Infratemporal fossa type A approach is an effective method for treating FNS of JF.

Facial Schwannoma Management Outcomes: A Systematic Review of the Literature

OBJECTIVE

To evaluate facial nerve outcomes of various management strategies for facial schwannomas by assimilating individualized patient data from the literature to address controversies in management.

DATA SOURCES

PubMed-National Center for Biotechnology Information and Scopus databases.

REVIEW METHODS

A systematic review of the literature was performed for studies regarding facial schwannomas. Studies were included if they presented patient-level data, type of intervention, pre- and postintervention House-Brackmann (HB) grades, and tumor location by facial nerve segment.

RESULTS

Individualized data from 487 patients were collected from 31 studies. Eighty (16.4%) facial schwannomas were managed with observation, 25 (5.1%) with surgical decompression, 20 (4.1%) with stereotactic radiosurgery, 225 (46.2%) with total resection, and 137 (28.1%) with subtotal resection/stripping surgery. Stripping surgery/subtotal resection with good preoperative facial nerve function maintained HB grade 1 or 2 in 96% of cases. With a total resection of intradural tumors, preoperative HB grade did not significantly affect facial nerve outcome (n = 45, P = .46). However, a lower preoperative HB grade was associated with a better facial nerve outcome with intratemporal tumors (n = 56, P = .009). When stereotactic radiosurgery was performed, 40% of patients had improved, 35% were stable, and 25% had worsened facial function. Facial nerve decompression rarely affected short-term facial nerve status.

CONCLUSION

The data from this study help delineate which treatment strategies are best in which clinical scenarios. The findings can be used to develop a more definitive management algorithm for this complicated pathology.

Surgical Outcomes of Intratemporal Facial Nerve Schwannomas According to Facial Nerve Manipulation

OBJECTIVES

The aim of this study was to evaluate the preoperative and postoperative facial nerve (FN) function in patients with FN schwannoma (FNS) and analyze the duration of preoperative facial palsy according to the preoperative and postoperative facial function.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 29 patients with FNS who underwent surgery. We evaluated the FN function according to the type of FN manipulation and location of the anastomoses in the cable nerve graft, and we also analyzed the duration of facial palsy according to the facial function before and after surgery.

RESULTS

All 4 patients who underwent nerve-stripping surgery had the House-Brackmann (H-B) Grade III, 12 of 21 who underwent a cable nerve graft had the H-B Grade III or better postoperatively, and all 4 who underwent a hypoglossal facial crossover had the H-B Grade IV. Patients who underwent cable nerve grafting were more likely to have better FN function when the proximal anastomosis site was located in the internal auditory canal, geniculate ganglion, tympanic segment of FN, and distal end in the mastoid segment of FN. The duration of preoperative facial palsy was statistically shorter in patients with better postoperative facial function.

CONCLUSION

Surgery can be considered in patients with FNS who have the H-B Grade III or worse. A shorter duration of facial palsy prior to surgery resulted in better postoperative facial function.

Intraparotid facial nerve schwannoma: a 17-year, single-institution experience of diagnosis and management

BACKGROUND

Intraparotid facial nerve schwannoma (IFNS) is rare and its definite preoperative diagnosis is challenging.

OBJECTIVE

To improve available knowledge regarding the diagnosis of IFNS and to suggest an appropriate treatment plan.

MATERIAL AND METHODS

We retrospectively analyzed medical records of IFNS patients at our hospital. Inclusion criteria were surgery (from January 2000, to December 2016) for a parotid mass, pathologically diagnosed as a schwannoma.

RESULTS

The study included 42 eligible patients who had undergone tumor resection from 5977 parotid tumor patients. Mostly presented hard-textured (18/39) or medium-textured (15/39), with limited mobility (21/39) mass (three tumors were not palpable). Their facial nerve function outcomes were House-Brackmann Grade I (n = 14), Grade II (n = 7), Grade III (n = 11), Grade IV (n = 5), Grade V (n = 3), and Grade VI (n = 2). Significant differences were noted in results based on different surgical methods used (p = .000) and tumor involvement (p = .002).

CONCLUSIONS AND SIGNIFICANCE

A hard-textured tumor with limited mobility mass in the parotid gland should prompt the diagnosis of a schwannoma. Tumors involving main trunk usually lead to unsatisfactory facial nerve outcomes. Facial nerve preservation should always be essential, and stripping surgery or intracapsular enucleation could be the preferred surgical methods of choice.

Intraparotid facial nerve schwannoma: two case reports and a review of the literature

SUMMARY

Schwannomas are rare benign tumours that arise from Schwann cells. The most known and studied is the intracranial vestibular schwannoma, even if it is not the most frequent. More often schwannomas arise from peripheral sensitive nerves, and the vagous is most involved among the cranial nerves. Intraparotid schwannomas account for just 10% of all facial involvement, so they are an extremely rare localisation. At present, there are less than 100 cases described in the literature. We performed a retrospective analysis of parotidectomy in two Italian hospitals and present two cases of intraparotid schwannoma and a review of the literature. In the first case, we performed a parotidectomy with a stripping of tumour from the nerve. In the other case, a hypoglossal-facial neurorrhaphy was performed. Follow-up was 24 months in the first (House-Brackmann II degree in temporal-ocular and III in facial-cervical branches) and 30 months in the second case (House-Brackmann III degree in both temporal-ocular and facial-cervical branches). Preoperative diagnosis of facial nerve schwannoma is a challenge; however, it is extremely important since post-operative palsy is common and often higher grade. Unfortunately, schwannoma has similar radiologic finding as more common pleomorphic adenoma and often FNAC is not helpful. Due to its rarity and benign nature, there is debate in the literature on the need for surgical removal. Wait-and-see is a valid option, but may could give problems in secondary surgery. Stripping or near-total removal can be useful in cases of limited involvement of the nerve. Neurorrhaphy can provide good functional results when facial sacrifice is needed.

The Natural History of Facial Schwannomas: A Meta-Analysis of Case Series

Objective  This study is to establish predictors of facial paralysis and auditory morbidity secondary to facial schwannomas by assimilating individualized patient data from the literature. Design  A systematic review of the literature was conducted for studies regarding facial schwannomas. Studies were only included if they presented patient level data, House-Brackmann grades, and tumor location by facial nerve segment. Odds ratios (OR) were estimated using generalized linear mixed models. Main Outcome Measures  Facial weakness and hearing loss. Results  Data from 504 patients were collected from 32 studies. The geniculate ganglion was the most common facial nerve segment involved (39.3%). A greater number of facial nerve segments involved was positively associated with both facial weakness and hearing loss, whereas tumor diameter did not correlate with either morbidity. Intratemporal involvement was associated with higher odds of facial weakness (OR = 4.78, p  < 0.001), intradural involvement was negatively associated with facial weakness (OR = 0.56, p  = 0.004), and extratemporal involvement was not a predictor of facial weakness (OR = 0.68, p  = 0.27). The odds of hearing loss increased with more proximal location of the tumor (intradural: OR = 3.26, p  < 0.001; intratemporal: OR = 0.60, p  = 0.14; extratemporal: OR = 0.27, p  = 0.01). Conclusion  The most important factors associated with facial weakness and hearing loss are tumor location and the number of facial nerve segments involved. An understanding of the factors that contribute most heavily to the natural morbidity can help guide the appropriate timing and type of intervention in future cases of facial schwannoma.

Evaluation and Management of Facial Nerve Schwannoma

Facial nerve schwannomas are benign peripheral nerve sheath tumors that arise from Schwann cells, and most commonly present with facial paresis and/or hearing loss. Computed tomography and MRI are critical to diagnosis. Management decisions are based on tumor size, facial function, and hearing status. Observation is usually the best option in patients with good facial function. For patients with poor facial function, the authors favor surgical resection with facial reanimation. There is growing evidence to support radiation treatment in patients with progressively worsening moderate facial paresis and growing tumors.

Geniculate Ganglion Tumors: Clinical Presentation and Surgical Results

OBJECTIVE

Facial nerve tumors are rare lesions mostly located in the geniculate ganglion. This study aims to compare those tumors limited to the geniculate ganglion in terms of clinical features and postoperative outcomes.

STUDY DESIGN

Case series with chart review.

SETTINGS

University tertiary reference center.

SUBJECTS AND METHODS

Medical charts were reviewed for 17 patients who had surgery for geniculate ganglion tumor removal (10 hemangiomas, 6 schwannomas, 1 meningioma). Hemangiomas and schwannomas were compared for preoperative facial nerve function, hearing, tumor size, and postoperative outcomes.

RESULTS

Facial palsy was observed in all cases. Regarding the preoperative facial nerve function, severe facial palsy (House-Brackmann grades V and VI) was present in 70% of cases for hemangiomas and for no case of schwannoma (P = .01), although hemangiomas were significantly smaller tumors (P = .01). Hearing loss was observed in 4 cases (23.5%) and was related to tumor volume (P < .0001). A complete excision was achieved in all cases, and a facial nerve graft was performed immediately after interruption in 16 patients (94%). Postoperative facial nerve function was improved or stabilized in 94% of cases. A preoperative House-Brackman grade VI was shown as a negative factor for postoperative facial nerve function.

CONCLUSIONS

Differences in clinical presentations could help in establishing the good therapeutic option depending on the tumor type. Surgery, when indicated, is safe and effective, and postoperative outcomes are not related to tumor type.

Gamma Knife radiosurgery in the treatment of abducens nerve schwannomas: a retrospective study

OBJECTIVE Of the intracranial schwannomas, those arising from the vestibular nerves are the most common. Abducens nerve (AN) schwannomas are very rare, and there is limited literature on their optimal management. Therapeutic options include surgery and/or stereotactic radiosurgery. The aim of this study was to evaluate the role of Gamma Knife radiosurgery (GKRS) in these sixth cranial nerve (CN) schwannomas. METHODS The authors performed a retrospective analysis of patients who had undergone GKRS for intracranial tumors at their institute in the period from 2003 to 2010. Inclusion criteria were as follows: isolated AN paresis on presentation, a lesion along the course of the sixth CN, and imaging features characteristic of a schwannoma. Patients with other CN deficits and neurofibromatosis Type 2 were excluded. Symptomatic improvement was defined as the resolution of or an improvement in diplopia noted on a subjective basis or as an improvement in lateral eyeball excursion noted objectively on follow-up. A reduction in tumor volume by at least 20%, as noted by comparing the pre- and post-GKRS images, was deemed significant. RESULTS Six patients with a mean age of 37.1 years (range 17-55 years) underwent primary GKRS. There were 2 prepontine cistern, 3 cavernous sinus, and 1 cisterno-cavernous tumor. The mean duration of symptoms was 6.1 months (range 3-12 months). The mean tumor volume was 3.3 cm³ (range 1.5-4.8 cm³). The mean tumor margin radiation dose was 12.5 Gy (range 12-14 Gy), while the median margin dose was 12 Gy (50% isodose line). The median number of isocenters used was 5 (range 4-8). The brainstem received an average 8.35-Gy radiation dosage (range 5.5-11 Gy). The mean follow-up duration was 44.3 months (range 24-78 months). Symptoms remained stable in 1 patient, improved in 3, and resolved in 2 (total improvement 83%). Magnetic resonance imaging at the last follow-up showed a stable tumor size in 3 patients (50%) and a reduction in the other 3. Thus, the tumor control rate achieved was 100%. No new CN deficits were noted. CONCLUSIONS Abducens nerve schwannomas are rare intracranial tumors. They can be cavernous, cisternal, or cisterno-cavernous in location. Excellent tumor control rates and symptomatic improvement can be achieved with GKRS, which appears to be a safe and effective, minimally invasive modality for the treatment of such lesions. Therefore, it is reasonable to consider GKRS as the initial treatment of choice for this rare pathology. Long-term follow-up will be essential for further recommendations.

Intratemporal facial nerve schwannoma: clinical presentation and management

Facial nerve schwannoma is the most common facial nerve tumor, but its therapeutic strategy remains debated. The aim of this study is to analyze the facial nerve function and the hearing outcomes after surgery or wait-and-scan policy in a facial nerve schwannoma series. A monocentric retrospective review of medical charts of patients followed for an intratemporal facial nerve schwannoma between 1988 and 2013 was performed. Twenty-two patients were included. Data were extracted pertaining to the following variables: patient demographics, tumor localization, clinical and imaging features, facial nerve function and hearing levels, and details of surgical intervention. The majority of tumors were located at the geniculate ganglion. Initial symptoms were mainly facial palsy and hearing loss. The average follow-up was 4.8 ± 4.5 years. Nineteen patients underwent surgery, and three patients were observed. After surgery, 11 patients had a stable or improved facial nerve function (57.9 %), and 8 patients had a worsened facial nerve function (42.1 %). Facial nerve function was in the majority of cases a HB grade III, depending on surgical strategy. No patient presented a postoperative HB grade V or VI. Regarding the hearing, it remained stable after surgery in 52.6 % of cases, and improved in 10.5 % of cases. Among monitored patients, facial nerve function and hearing remained stable. Surgery for facial nerve schwannoma is a safe and effective option in the treatment of these tumors.

Stripping surgery in facial nerve schwannomas with favorable facial nerve function

OBJECTIVE

We report 18 cases of facial nerve schwannomas in which stripping surgery was attempted to preserve facial nerve integrity and favorable facial nerve function.

METHODS

We attempted stripping surgery on 18 cases of facial nerve schwannomas. Postoperative facial nerve function was evaluated.

RESULTS

Stripping surgery was successfully achieved in 11 cases, and facial nerve decompression was performed on the remaining 7 cases in which stripping surgery was impossible. Favorable facial nerve function was successfully maintained in all cases who underwent stripping surgery and 5 of 7 cases who underwent facial nerve decompression.

CONCLUSIONS

It was possible to accomplish stripping surgery in most cases with favorable facial nerve function, which maintained good facial nerve function after total tumor removal.

Gamma Knife surgery for facial nerve schwannomas

OBJECT

The aim of this study was to evaluate the tumor control rate and functional outcomes after Gamma Knife surgery (GKS) among patients with a facial nerve schwannoma.

METHODS

The authors reviewed the radiological data and clinical records for 14 patients who had consecutively undergone GKS for a facial nerve schwannoma. Before GKS, 12 patients had facial palsy, 7 patients had hearing disturbance, and 5 patients had undergone partial or subtotal tumor resection. The mean and median tumor volumes were 3707 mm(3) and 3000 mm(3), respectively (range 117-10,100 mm(3)). The mean tumor margin dose was 13.2 Gy (range 12-15 Gy), and the mean maximum tumor dose was 26.4 Gy (range 24-30 Gy). The mean follow-up period was 80.7 months (range 2-170 months).

RESULTS

Control of tumor growth was achieved in all 12 (100%) patients who were followed up for longer than 2 years. After GKS, facial nerve function improved in 2 patients, remained unchanged in 9 patients, and worsened in 3 patients. All patients who had had serviceable hearing at the preliminary examination maintained their hearing at a useful level after GKS. Other than mild tinnitus reported by 3 patients, no other major complications developed.

CONCLUSIONS

GKS for facial nerve schwannomas resulted in excellent tumor control rates and functional outcomes. GKS might be a good primary treatment option for patients with a small- to medium-sized facial nerve schwannoma when facial nerve function and hearing are relatively preserved.

Surgical findings to differentiate between facial nerve schwannoma and vestibular schwannoma

Objectives

Facial nerve schwannomas may be misdiagnosed as vestibular schwannomas (VSs) if the tumor is confined to the internal auditory canal (IAC) without involvement the geniculated ganglion or labyrinthine segment of facial nerve. Because facial nerve schwannomas may be misdiagnosed as VSs, we investigated the differences between the two.

Methods

The study included 187 patients with a preoperative diagnosis of VS. Of these, six were diagnosed with facial nerve schwannomas during surgery. We reviewed the preoperative evaluations and surgical findings of facial nerve schwannomas mimicking VSs.

Results

No useful preoperative predictors are available for facial nerve schwannomas mimicking VSs. Facial nerve schwannomas are usually confined to the IAC. After opening the dura of the IAC, a facial nerve schwannoma can be diagnosed after identifying a normal-appearing nerve located lateral to the tumor. When this was the case, we performed facial nerve preservation surgery or decompression.

Conclusion

Facial nerve schwannomas can be differentiated from VSs by identifying specific findings during surgery.

Intraoperatively diagnosed cerebellopontine angle facial nerve schwannoma: how to deal with it

OBJECTIVE

This study aimed to report our experience in the management of patients with intraoperatively diagnosed intracranial facial nerve schwannomas (FNSs) and propose a decision-making strategy.

METHODS

Twenty-three patients with FNS of the internal auditory canal and/or cerebellopontine angle operated on between 1992 and 2012 were identified.

RESULTS

Preoperatively, all cases have been radiographically diagnosed as vestibular schwannomas. Operative procedures consisted of total tumor resection with grafting in 43.4% of patients, near-total resection leaving behind the tumor capsule overlying the facial nerve in 21.7%, total tumor resection with preservation of anatomic continuity of the facial nerve in 13%, and subtotal resection in 4.3%. Four patients (17.4%) underwent bony decompression with no tumor removal.

CONCLUSION

Management of FNS diagnosed at surgery represents a significant clinical challenge. We considered total tumor resection with grafting when patients presented with preoperative facial nerve palsy (≥ grade III). Both subtotal and near-total tumor removal can be performed in patients with preoperative good facial function and/or large tumors with brainstem compression. Patients with small tumors who were selected for hearing preservation surgery can be considered for bony decompression. Fascicle preservation surgery may be an option when a clear cleavage plane between the tumor and the facial nerve is found.

Facial nerve schwannomas of the cerebellopontine angle: the mayo clinic experience

Background There is often controversy regarding the optimal management for patients with facial nerve schwannomas (FNSs) of the cerebellopontine angle (CPA). Methods The clinical and radiological outcomes in 14 patients with CPA FNS were retrospectively reviewed. Results Patients underwent resection with anatomic nerve preservation (n = 3), facial-hypoglossal nerve anastomosis (n = 4), gamma knife radiosurgery (GKS) (n = 6), or observation (n = 1). A total of 83% of tumors that underwent GKS were stable or decreased in size. No patient who underwent resection showed evidence of tumor recurrence; the tumor under observation remained unchanged with normal facial function at the time of the last follow-up. Facial function was decreased in 57%, stable in 14%, and improved in 29% of those who underwent microsurgery. A total of 67% of patients who underwent GKS had stable facial function. Serviceable hearing was maintained in 50% of patients in the GKS group and 67% of the tumor resection group. Mean and median follow-up was 48 and 43 months, respectively (range, 12 to 95 months). Conclusion Observation should be the primary management when encountered with FNS of the CPA in those with good neurologic function. Microsurgery or radiosurgery may be used in those with poor facial function or tumor progression.

Are the current treatment strategies for facial nerve schwannoma appropriate also for complex cases?

OBJECTIVES

To describe the decision-making strategies for complex facial nerve schwannomas (FNSs).

MATERIALS AND METHODS

Charts belonging to 103 consecutive patients with facial nerve tumors managed between 1990 and 2011 were examined retrospectively to identify complex FNSs. To be classified as complex, at least one of the following criteria had to be met: (1) FNS with large intraparotid tumor component and preoperative good facial nerve function (3 cases); (2) multiple-segment FNSs with extension to both the cerebellopontine angle and the middle cranial fossa in patients with preoperative good hearing (5 cases); (3) fast-growing FNS with preoperative good facial nerve function (4 cases), and (4) large FNS compressing the temporal lobe with preoperative normal facial nerve function (1 case).

RESULTS

Thirteen patients were classified as complex; 12 patients had total tumor removal with sural nerve grafting and 1 patient had partial tumor removal. Two patients with intratemporal-intraparotid FNS underwent a transmastoid-transparotid approach. One patient with a tumor extending from the geniculate ganglion to the parotid portion of the facial nerve underwent a combined middle fossa transmastoid-transparotid approach. A transcochlear approach with temporal craniotomy was performed in all the patients with multiple-segment FNS as well as in patients with fast-growing tumors extending both in the cerebellopontine angle and middle cranial fossa. A partial tumor removal through the middle fossa approach was performed in 1 patient with a large tumor compressing the temporal lobe.

CONCLUSIONS

Therapeutic options for patients with FNS include surgical intervention, observation and radiotherapy. Nowadays, surgical resection with facial nerve repair is usually the standard management for patients with poor facial function (House-Brackmann grade III or worse). In patients presenting with normal or near-normal facial nerve function, initial observation with periodic examination and imaging is usually recommended. However, on rare occasions surgeons can be faced with a situation in which the management decision-making process is particularly challenging. In these complex cases treatment should be individualized. We recommend early surgical intervention regardless of the preoperative facial and hearing functions in the following cases: intratemporal FNSs extending with a large tumor component into the parotid, multiple-segment FNSs extending in both the cerebellopontine angle and the middle cranial fossa, fast-growing FNSs, and large FNSs with temporal lobe compression.

Surgical management of internal auditory canal and cerebellopontine angle facial nerve schwannoma

OBJECTIVE

To investigate the long-term patient outcomes after tumor debulking for internal auditory canal facial schwannoma (FNS).

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Patients operated on between 1998 and 2010 for a preoperative diagnosis of vestibular schwannoma with the intraoperative identification FNS instead.

INTERVENTION

Diagnostic and therapeutic.

MAIN OUTCOME MEASURES

House-Brackmann facial nerve score immediately and at long-term follow-up (>1 yr); recurrence of tumor.

RESULTS

Sixteen patients were identified who were presumed to have vestibular schwannoma but intraoperatively were diagnosed with facial nerve schwannoma. Eleven underwent debulking surgery (67%-99% tumor removal), 2 underwent decompression only, 2 were diagnosed with nervus intermedius tumors and had total tumor removal with preservation of the motor branch of cranial nerve VII, and 1 had complete tumor removal with facial nerve grafting. Five of 11 debulking patients underwent the middle cranial fossa approach for tumor removal; the remainder had translabyrinthine resections. One debulking patient was lost to follow-up. Nine of 10 patients with long-term follow-up had House-Brackmann Grade I or II facial function. One patient had recurrence of the tumor that required revision surgery with total removal and facial nerve grafting.

CONCLUSION

Tumor debulking for FNS provides an opportunity for tumor removal and excellent facial nerve function. Continuous facial nerve monitoring is vital for successful debulking surgery. FNS debulking is feasible via the middle cranial fossa approach. Serial postoperative imaging is warranted to monitor for recurrence.

Management options for intraparotid facial nerve schwannoma

CONCLUSION

Limited intraparotid facial nerve schwannoma (IFNS) and IFNS with intratemporal involvement should be managed separately because of their different characteristics. Limited IFNS with House-Brackman (HB) grade ≤ II should undergo tumor removal only if it can be resected easily off the nerve. For IFNS with intratemporal involvement and a HB grade ≤ II, a conservative treatment (i.e. wait-and-see alone, or bone decompression) is recommended.

OBJECTIVE

To provide management options for IFNS.

METHODS

From 1996 to 2011, seven cases of IFNS underwent surgical treatment. Clinical and radiologic findings, surgical approach, and preoperative and postoperative facial nerve function were analyzed retrospectively.

RESULTS

Three IFNSs extended into the mastoid (43%). Two of the three patients with mastoid extension progressed to HB grade IV after the operation because the facial nerve was sacrificed, whereas the other one who underwent biopsy and decompression remained at HB grade II. Four limited IFNSs (57%) presented with grades I-II, three of which were removed while preserving facial nerve function and the other was removed by cystic decompression. No recurrence or significant growth of the non-resected schwannoma was observed.

Evolution in the management of facial nerve schwannoma

OBJECTIVE

To design a treatment algorithm based on experience with facial nerve schwannomas (FNS) over a 30-year period.

STUDY DESIGN

Retrospective chart review.

METHOD

Seventy-nine patients with facial nerve schwannomas seen from 1979 through 2009 at a tertiary referral private otologic practice were categorized by treatment modality. Interventions included surgical resection with grafting, bony decompression, observation, or stereotactic radiation. Outcome measures included House-Brackmann facial nerve grade before and after intervention as well as change in facial nerve grade, tumor size, involved segments of nerve, time to intervention.

RESULTS

Thirty-seven patients (46.8%) ultimately underwent surgical excision with grafting or primary anastomosis, 21 (26.6%) underwent bony decompression alone, 15 (19.0%) were managed with observation only, and 6 (7.6%) had stereotactic radiation. Through 1995, 85% of cases had surgical resection and none had observation only. Of the 52 patients seen after 1995, 27% had surgical resection and grafting, 33% had bony decompression, 29% were managed with observation alone, and 11% had radiotherapy. Facial nerve grade was maintained or improved over the follow-up period (mean time = 3.9 years) in 78.9% of the decompression group and 100% of the observation and radiation groups compared to 54.8% of the resection group (P ≤ .012).

CONCLUSIONS

Surgical resection and grafting, once widely accepted and practiced, has in many cases given way to observation, bony decompression, or stereotactic radiation. A wide armamentarium of options is available to the neurotologist treating facial nerve schwannomas with the ability to preserve facial function for a longer period of time.

Facial nerve schwannoma

PURPOSE OF REVIEW

The purpose of this review is to summarize the current literature on facial nerve schwannoma and make practical recommendations based on best practices for the management of this difficult but benign neoplasm.

RECENT FINDINGS

Facial nerve schwannoma can be asymptomatic or can present with progressive or acute facial nerve palsy. Associated otological symptoms such as conductive and/or sensorineural hearing loss can occur. The tumor is usually slow-growing and can involve multiple segments of the nerve. Radiographic imaging and facial nerve electrical testing can be helpful in treatment planning. Options for management can include observation, decompression, stripping, resection with grafting, and possibly radiotherapy. Future adjunctive therapies to improve facial nerve function may include electrical stimulation, steroid hormones, and possibly stem cell therapy.

SUMMARY

Treatment of facial schwannoma is individualized based on patient symptoms, history, and clinicoradiographic evaluation. Not all patients require surgery. As the tumor can involve multiple segments of the nerve, the surgeon attempting removal should be familiar with modern neurotological surgical techniques. Ongoing translational research will hopefully allow us to decrease facial nerve morbidity in these patients.

STEREOTACTIC RADIOSURGERY AND FRACTIONATED STEREOTACTIC RADIOTHERAPY FOR THE TREATMENT OF NONACOUSTIC CRANIAL NERVE SCHWANNOMAS

OBJECTIVE

To review outcomes after fractionated stereotactic radiotherapy (FSR) and stereotactic radiosurgery (SRS) for nonacoustic cranial nerve schwannomas.

METHODS

We reviewed medical records of 39 patients who received FSR or SRS for nonacoustic cranial nerve schwannomas at our institution during the period from 1996 to 2007.

RESULTS

Tumors involved Cranial Nerves V (n = 19), III (n = 2), VI (n = 3), VII (n = 5), IX (n = 2), X (n = 5), and XII (n = 2) and the cavernous sinus (n = 1). Irradiation was performed after partial resection, biopsy, or no previous surgery in 16, 2, and 21 patients, respectively. Twenty-four patients received FSR, delivered in 1.8- to 2.0-Gy fractions to a median dose of 50.4 Gy (range, 45.0–54.0 Gy). Fifteen patients received SRS to a median dose of 12.0 Gy (range, 12–15 Gy). Mild acute toxicity occurred in 23% of the patients. The 2-year actuarial tumor control rate after FSR and SRS was 95%. The median follow-up period was 24 months. Changes in cranial nerve deficits after stereotactic irradiation were analyzed for patients with follow-up periods greater than 12 months (n = 26); cranial nerve deficits improved in 50%, were stable in 46%, and worsened in 4% of the patients. No significant difference was observed for FSR compared with SRS with regard to local control or to improvement of cranial nerve-related symptoms (P = 0.17).

CONCLUSION

SRS and FSR are both well-tolerated treatments for nonacoustic cranial nerve schwannomas, providing excellent tumor control and a high likelihood of symptomatic improvement.