Individualizing Hearing Preservation in Acoustic Neuroma Surgery

Surgical series of hearing preservation in acoustic neuroma usually emphasize a team's results with one particular technique. This report reviews acoustic neuroma outcomes of individualizing the surgical approach to patient and tumor characteristics. This study reviews 60 consecutive hearing preservation acoustic neuroma surgeries in a total series of 330 acoustic neuromas. Tumor sizes ranged from 0.3 to 4 cm in patients ranging from 23 to 74 years of age. Middle fossa surgery was performed in 57%, retrosigmoid in 43%. Overall, measurable hearing was preserved in 77%, and useful hearing in 67%. Among middle fossa cases, 85% had measurable and 74% had useful hearing. Among retrosigmoid surgeries, 65% had measurable hearing and 58% had useful hearing. Overall, long-term facial nerve function was excellent (grade I or II) in 90% and poor (grade V or VI) in 2%. There was one case of bacterial meningitis(2%), and cerebrospinal fluid leaks requiring surgery occurred in four patients (7%). The hearing preservation and other outcome parameters in this series compare favorably with other reports. We believe that individualizing the surgical approach to the patient's tumor characteristics and clinical features contributed to the high rate of hearing preservation.     

Endolymphatic duct status during middle fossa dissection of the internal auditory canal: a human temporal bone radiographic study

OBJECTIVE: Successful hearing preservation after acoustic neuroma resection is sometimes complicated by delayed hearing deterioration. The middle fossa approach appears to offer superior long-term hearing results when compared to the retrosigmoid surgical approach. The goal of this study is to investigate the hypothesis that internal auditory canal (IAC) drilling during middle fossa acoustic neuroma removal is associated with a lower incidence of endolymphatic duct (ELD) injury, a potential cause of delayed hearing loss (HL) known to accompany retrosigmoid hearing preservation dissection techniques. STUDY DESIGN: A human temporal bone anatomic and radiographic study complemented with a literature review. METHODS: Twenty human temporal bones were analyzed with high-resolution multislice computed tomography (HRMCT) and subjected to standard extended middle fossa IAC dissection with labyrinthine preservation and follow-up HRMCT for analyses of the ELD. RESULTS: Zero of 20 (0%) temporal bones were found to have violation of the ELD with preservation of the labyrinthine structures and the endolymphatic sac. Reviews of human and animal studies indicate that injury to the ELD may create endolymphatic hydrops, a known cause of hearing deterioration. CONCLUSION: The ELD is not vulnerable to injury during IAC dissection using the middle fossa approach. A previous radiographic study has shown that the ELD is violated in 24% of temporal bones during retrosigmoid dissection of the IAC. These findings support and may help explain other outcome studies that show that long-term hearing results are superior with the use of the middle fossa approach when compared to results following retrosigmoid dissection.     

Hearing preservation in acoustic neuroma surgery: middle fossa versus retrosigmoid approach

OBJECTIVE: To compare the results of the middle fossa approach with those of the retrosigmoid approach in acoustic neuroma hearing preservation surgery. STUDY DESIGN: Retrospective review. SETTING: Tertiary care facility. PATIENTS: Patients of the otology service with acoustic neuromas and useful hearing. Fifteen intracanalicular tumors were removed via a middle fossa approach and matched with 15 intracanalicular tumors removed via the retrosigmoid approach. Four additional patients with larger tumors were operated on via the middle fossa approach and matched with patients having similar tumors removed via the retrosigmoid approach. MAIN OUTCOME MEASURES: The 1994 Committee on Hearing and Equilibrium guidelines for the evaluation of hearing preservation in acoustic neuroma were applied. Facial nerve results were graded according to the House-Brackmann grading scale 3 months postoperatively. RESULTS: In the group operated on by the middle fossa approach, the average preoperative pure-tone threshold average (PTA) was 23 dB with a word recognition score (WRS) of 79%, and the postoperative PTA averaged 49 dB with a mean WRS of 56%. In the group operated on by the retrosigmoid approach, the mean preoperative PTA was 16 dB with a WRS of 95% and a postoperative PTA value of 62 dB and WRS of 51% (hearing preservation rate of 47%). The middle fossa patients had an average change in PTA of 19 dB and an average change in WRS of 20% (hearing preservation rate of 57%). Overall, the retrosigmoid patients had an average change in PTA of 42 dB and an average change in WRS of 40%. The average change in PTA for larger tumors removed via the middle fossa approach was 32 dB, whereas all matched retrosigmoid patients lost all hearing. The rate of cerebrospinal fluid leak and facial nerve outcomes were similar between the two groups. The retrosigmoid group had a higher rate of postoperative headache. CONCLUSIONS: Compared with the retrosigmoid approach, the middle fossa approach for hearing preservation surgery yields better hearing results for intracanalicular tumors and also has a lower incidence of postoperative headache.     

Results in otosurgically treated patients with acoustic neuroma. Part 1: Facial nerve function after translabyrinthine and middle fossa resection

BACKGROUND: Regardless of all efforts to preserve a residual hearing, facial nerve function is still the primary issue for patients with acoustic neuromas. Since alternative methods like the gamma-knife treatment are of increasing importance, results after surgery have to be compared and discussed critically. PATIENTS: The results of 538 patients operated at the Dept. of Otolaryngology, Head and Neck Surgery, University of Wuerzburg between 1989 and 2004 are presented. 392 had surgery via a middle fossa, 146 via a translabyrinthine approach. RESULTS: Shortly after surgery 82.2 % of patients showed no facial palsy. 74 patients had an incomplete, 7 a complete paresis. After 12 months 144 of the patients operated on via middle fossa approach showed no palsy, 13 had an incomplete and one a complete paresis. Out of 76 patients operated on translabyrinthine approach 75 had no paresis, one had an incomplete, and no patient had a complete paresis. There was no difference between intrameatal tumors and tumors extending beyond the porus. Regular facial nerve function was seen in 93 %, postoperatively. Permanent paresis was seen in 0.4 % of cases. CONCLUSION: Acoustic neuroma confined to the internal meatus or with minor extension into the cerebello-pontine angle (i. e. no contact to structures of the brain stem or vessels of the posterior fossa) are feasible for resection via a middle fossa or translabyrinthine approach. The possibility of hearing preservation combined with low morbidity and good results of facial nerve function makes these approaches the treatment of choice for this group of tumors.     

Neurotologic skull base surgery in pediatric patients.

OBJECTIVE: Innovations in diagnosis, surgical techniques, and perioperative care have dramatically improved outcomes in lateral skull base procedures in recent years. There is a belief, however, that children with skull base tumors have yet to benefit from these technological and procedural advances. The purpose of this study is to provide a clinical review of neurotologic skull base surgery in the pediatric population. STUDY DESIGN: Retrospective case review. SETTING: Private practice tertiary referral center. PATIENTS: Eighty-nine pediatric patients undergoing 115 neurotologic procedures for lateral skull base tumors from July 1992 to September 2003. MAIN OUTCOME MEASURES: Initial clinical presentation, tumor type, pre- and postoperative hearing and facial nerve status, treatment course, complications, and functional outcomes. RESULTS: The majority of tumors in this series were vestibular schwannomas, and 65 patients were diagnosed with neurofibromatosis Type 2. Surgical approaches included 70 middle fossa, 40 translabyrinthine, 2 transcochlear, 2 infratemporal fossa, and 1 retrosigmoid craniotomy. Complete tumor removal was accomplished in the majority of cases (97%), with good preservation of facial nerve function (House-Brackmann Grade I or II) in 80% of patients. In patients undergoing middle fossa surgery for hearing preservation, measurable hearing was preserved in 61.4% of cases. The incidence of complications was low. CONCLUSION: With advances in diagnostic procedures and use of current neurotologic techniques, pediatric patients may undergo successful treatment of lateral skull base tumors, with good functional outcomes and minimal morbidity.     

Audiometric findings in patients with acoustic neuroma

OBJECTIVE: Hearing loss remains the most common symptom associated with acoustic neuroma. This study documents the audiometric findings from 721 acoustic neuroma procedures. STUDY DESIGN: This was a retrospective study. The preoperative audiometric data were compiled and were analyzed by patient age, gender, tumor size, time of surgery, and neurofibromatosis Type 2 (NF 2). Postoperative audiometric data were arranged and compiled in the same way. The hearing classification proposed by the AAO-HNS was applied to all preoperative and postoperative cases. SETTING: Tertiary referral center. PATIENTS: Surgically confirmed acoustic neuroma patients who had not previously received surgical or radiosurgical therapy. Patients underwent surgery by the retrosigmoid approach. INTERVENTION: Surgical removal of an acoustic neuroma. MAIN OUTCOME RESULT: Provision of pure tone and speech data from a group of acoustic neuroma patients, including application of the recently introduced and accepted AAO-HNS hearing classification system. RESULTS: Preoperative audiometric data were obtained from 694 of 721 patients (96%), of whom 619 had measurable hearing. Postoperative audiometry was performed on 606 patients; 152 had usable data. The combined preoperative audiometric data revealed a high frequency sensorineural hearing loss. Word recognition was servicable. The postoperative pure tones and word recognition scores were worse than preoperative scores. Age, gender, tumor size, and time of surgery had some impact on the preoperative hearing and the postoperative result; NF 2 did not. CONCLUSIONS: The study confirms that hearing alteration is almost universal in acoustic neuroma patients. Hearing preservation is possible in a significant number of cases; however, the postoperative auditory function tends to be worse.     

A systematic approach to the surgical management of acoustic neuroma

Contemporary otomicrosurgical techniques have made total removal of acoustic tumor with preservation of the seventh and sometimes the eighth cranial nerves possible. The four approaches currently used in acoustic tumor surgery are the middle cranial fossa, the translabyrinthine, the suboccipital, and the combined translabyrinthine-suboccipital. This review examines the surgical results in the removal of more than 600 acoustic tumors and outlines a rationale for the choice of approach. Tumor size on computed tomographic scan and auditory reserve establish the parameters used in planning the surgical procedure. The translabyrinthine exposure is used most frequently followed by the combined translabyrinthine-suboccipital. The middle fossa and suboccipital approaches are used when preservation of hearing is attempted. Total removal of tumor was accomplished in more than 99% of patients with a mortality rate of less than 1%. Anatomic preservation of the facial nerve, which is directly related to tumor size, was achieved in more than 80% of patients. Preservation of hearing is unlikely when the tumor is larger than 2 cm; anatomic preservation of the cochlear nerve was successful in 73% of hearing preservation procedures.     

Surgical exposure of the facial nerve indications and techniques.

Lesions producing facial nerve palsy may occur within the temporal bone anywhere between the internal auditory canal and the stylomastoid foramen. Surgical exposure of this nerve may be necessary for decompression, grafting, rerouting, or removal of such lesions as acoustic tumour, meningioma, facial nerve neuroma, and cholesteatoma. Contemporary surgical exposure of the facial nerve has as its aim adequate exposure of the facial nerve at any point in its course, with preservation of hearing and vestibular function, without further injury to the facial nerve and the necessity for producing a mastoid cavity. When hearing and balance function are present, the transcanal-transtympanic approach to the horizontal segment of the facial nerve offers limited access to the facial nerve in its tympanic course. Wider exposure is obtained by postauricular transmastoid exposure of the tympanic and mastoid portions of the facial nerve. The middle fossa approach to the facial nerve offers access to the internal auditory canal and labyrinthine portions of the nerve, whereas the retrolabyrinthine approach offers access to the facial nerve in the posterior fossa. Total facial nerve exposure with preservation of hearing and balance function is obtained by the combined transmastoid and middle cranial fossa approach. In individuals who have lost all function of hearing and balance, the postauricular translabyrinthine approach offers total exposure of the facial nerve within the temporal bone and posterior fossa. The aim of this discussion was to present in succinct fashion a systematized approach to surgical exposure of the facial nerve within the temporal bone and posterior fossa.     

The evolution of surgical approaches for posterior fossa meningiomas.

OBJECTIVE: To evaluate surgical outcomes for the treatment of posterior fossa meningiomas at the House Ear Clinic from 1987 to 2001. We review our current treatment algorithm and present our postoperative outcomes with attention to facial and auditory neural preservation. STUDY DESIGN: Retrospective review. SETTING: Tertiary care center. PATIENTS: Medical records of 71 patients who underwent posterior fossa meningioma surgery at the House Ear Clinic were reviewed. INTERVENTION: All patients had surgical removal of their meningioma via translabyrinthine, transcochlear, retrosigmoid, extended middle fossa, or combined petrosal approaches by House Ear Clinic neurotologists and neurosurgeons. MAIN OUTCOME MEASURES: Preoperative and postoperative auditory and facial nerve function data were collected. Patient and tumor characteristics including presenting symptoms, completion of tumor resection, and complications secondary to surgery were also recorded. RESULTS: The most common presenting symptoms in this series were otologic, with hearing loss (61%), tinnitus (58%), and imbalance (58%) as the three most common. Gross total resection was achieved in 67 (94%) patients. Hearing-preservation surgery was attempted in 37 (52%) patients (68% via extended middle fossa or combined approach). Twenty-one patients with preoperative Class A hearing had follow-up audiometric data and 18 (86%) had serviceable hearing preserved. Excluding transcochlear craniotomies, 85% of patients had normal facial nerve function postoperatively. Cerebrospinal fluid leak (6%) was the most common complication. CONCLUSIONS: Advances in microsurgical techniques have greatly changed our management of patients with posterior fossa meningiomas. These changes have reduced postoperative morbidity. Specifically, use of the anterior and posterior petrosal approaches has facilitated facial and auditory neural preservation while not compromising the extent of tumor excision.     

Results of surgery by the modified extended middle cranial fossa approach in 100 patients with acoustic neuroma

The results of surgery by the middle cranial fossa (MCF) approach or the modified extended MCF approach in 100 patients with acoustic neuroma are reported. The rates of facial nerve preservation, tumor removal, and hearing preservation were reported and discussed. This surgical procedure can be applied to tumors of any size, from tumors confined to the internal auditory canal to those extending into the posterior fossa.     

Adjunctive use of endoscopy during acoustic neuroma surgery.

OBJECTIVE/HYPOTHESIS: In specific clinical situations, endoscopes offer better visualization than the microscope during acoustic neuroma (vestibular schwannoma) surgery and can therefore decrease the incidence of the postoperative complications of cerebrospinal fluid (CSF) leakage and recurrence of tumor. This study was undertaken to determine if the use of adjunctive endoscopy provides complementary information to the operating surgeon during surgery for acoustic neuromas. METHOD: Seventy-eight patients with acoustic neuromas underwent tumor excision by two neurotologists (PAW., D.S.P.), together with their respective neurosurgical partners, via a retrosigmoid (suboccipital) approach (n = 68), translabyrinthine approach (n = 7), or middle cranial fossa approach (n = 3). Endoscopy with a rigid glass lens endoscope was used during tumor removal to examine posterior fossa neurovascular structures, and after tumor excision to inspect the internal auditory canal (IAC), inner ear, and middle ear, depending on the approach used. One of the authors (D.S.P.) has not used adjunctive endoscopy during resections via the translabyrinthine and middle cranial fossa approaches, and therefore, these cases were excluded from the data collection and analysis. RESULTS: Complete tumor excision was achieved in 73 patients. Endoscopy allowed improved identification of tumor and adjacent neurovascular relationships in all cases. In addition, residual tumor at the fundus of the IAC (n = 11) and exposed air cells (n = 24) not seen with the microscope during retrosigmoid approaches were identified endoscopically. In one of the translabyrinthine cases, the endoscope allowed identification of open air cells not visualized with the microscope. None of the 78 patients developed CSF rhinorrhea. Incorporating the endoscope did not significantly increase operative time. CONCLUSIONS: Endoscopy can be performed safely during surgery to remove acoustic neuromas. The adjunctive use of endoscopy may offer some advantages including improved visualization, more complete tumor removal, and a lowered risk of CSF leakage.     

Surgical anatomy of the petrous canal and posterior cranial fossa in relation to hearing preservation in surgery of acoustic neuroma

The suboccipital (retrosigmoid) and the middle fossa routes are recommended for preservation of hearing in surgery for acoustic neuroma. We carried out a comparative study of the critical distances and bony landmarks on 520 petrous bones. Unlike the transtemporal route, the suboccipital approach offers no landmarks for identification of the common crus, the vestibule or the facial nerve; the lateral portion of the internal auditory canal is not always seen. The fundus can be seen in only 50% of bones without opening the labyrinth.     

Steroid and vasoactive treatment for acute deafness after attempted hearing preservation acoustic neuroma surgery

OBJECTIVE: To investigate whether intravenous steroid and vasoactive therapy in the acute postoperative period improves hearing outcome in patients who develop acute deafness after attempted hearing preservation surgery for acoustic neuroma (AN) through a retrosigmoid or a middle cranial fossa approach. STUDY DESIGN AND SETTING: Retrospective controlled study in a tertiary care center. Thirty-six patients who had developed acute deafness after hearing preservation surgery for treatment of an AN were reviewed. Preoperative AAOHNS hearing class was A in 2, B in 2 and D in 32 patients. Twenty-seven patients were treated with prednisolone, hydroxyethyl starch 3% and pentoxifylline intravenously for a period of at least 5 days. Nine patients (controls) did not receive any specific steroid or vasoactive therapy. RESULTS: All patients in both groups remained deaf. CONCLUSIONS: Intravenous therapy with prednisolone, hydroxyethyl starch 3% and pentoxifylline in the acute postoperative period does not improve hearing in patients who develop acute deafness after attempted hearing preservation surgery for AN.     

Intraoperative corticosteroids in acoustic tumor surgery.

BACKGROUND: Corticosteroids are frequently used for the prevention and treatment of neural edema. Although perioperative steroid therapy has been used in patients undergoing acoustic neuroma removal, the efficacy of such therapy has not been previously documented. METHODS: A retrospective review of 169 patients who underwent acoustic neuroma surgery with (n = 75) or without (n = 94) a single dose of intraoperative corticosteroids was performed. Tumor size ranged from 0.4 cm to 6 cm (mean, 2.1; SD, 1.0) The translabyrinthine approach was used in 85% of the patients, and the middle cranial fossa approach was used in 13%. Data were analyzed for differences in postoperative facial function and complication rates. RESULTS: After controlling for differences in tumor size, no significant effects of steroid therapy were found for any of the outcome variables. CONCLUSIONS: This retrospective study showed no apparent benefit from intraoperative steroid use in acoustic neuroma surgery. A prospective, randomized, placebo-controlled trial should be performed to confirm these findings.     

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.     

Translabyrinthine removal of large acoustic neuromas in young adults

OBJECTIVE: the authors reviewed the clinical manifestations and the surgical outcomes in a series of young patients who underwent removal of large acoustic neuromas via the translabyrinthine approach. METHODS: 40 young adults who underwent a translabyrinthine removal of acoustic neuromas 3 cm or greater in size were analyzed. The patient's age ranged from 17 to 30 years. The mean size of tumor was 4.25 cm. RESULTS: the primary symptoms are similar to those in adult but usually less intense. The average interval time between the primary symptom and the diagnosis was 17 months. A high percentage of preoperative normal hearing (35%) and good facial function (100%) were noted. Translabyrinthine approach was used in all cases. Total removal was realised in 39 patients (97.5%). The facial nerve was anatomically preserved in 37 patients (92.5%). Twenty-six patients (65%) had a good facial function (House-Brackmann grade I or II) immediately or at 1 month after surgery, 11 patients (28%) achieved grade III or IV. Three patients underwent an immediate nerve repair after tumor removal. All of them recovered to grade III or IV 1 year after surgery. Postoperative complications were minimal. CONCLUSIONS: young adults may have a rapid growth rate but usually have minimal symptoms even with a large acoustic neuroma. The translabyrinthine approach has been used successfully in removal of large acoustic tumors of young patients, with the good result of facial nerve preservation and long-term tumor control.     

Temporal bone cholesteatoma

Clinical features of temporal bone cholesteatoma are miscellaneous, and sometimes misleading: signs of middle ear cholesteatoma, progressive or sudden facial palsy, sensorineural deafness as in acoustic neuroma, conductive deafness as in otosclerosis, secretory otitis media, or intracranial complications. Polytomography is the only way to pinpoint topography and extension. CT scanning is very useful in determining extension. Topography and severity of deafness are the guidelines for surgical approach. Among sixteen cases, total deafness was produced by the lesion itself in ten cases, and six had an intact inner ear; preservation of hearing was possible in only three. Supralabyrinthine cholesteatomas (five cases) are best managed by the middle fossa approach. Infralabyrinthine cholesteatomas (six cases) must be removed via the infratemporal approach with anterior displacement of the tympanic and mastoid segments of the facial nerve and permanent obliteration of the middle ear. Posterior perilabyrinthine cholesteatoma (five cases) may be removed by the otologic approach combined with the middle ear fossa approach if the inner ear is to be preserved. If hearing loss is total, the translabyrinthine approach can be used.     

Comparison of postoperative facial nerve outcomes between translabyrinthine and retrosigmoid approaches in matched-pair patients

OBJECTIVES/HYPOTHESIS: The objective was to assess whether the translabyrinthine approach for acoustic tumor removal offers better postoperative facial nerve function compared with the retrosigmoid approach. STUDY DESIGN: Retrospective case review from a tertiary otology referral center. METHODS: Patients who had undergone either retrosigmoid or translabyrinthine approach for removal of acoustic neuroma from January 1, 1980, to December 31, 1999, were included in the study. Two groups of patients were created, one containing retrosigmoid cases and the other, translabyrinthine. Attempts were made to match each retrosigmoid case to a translabyrinthine case with regard to tumor size, patient age, and date of operation. This matching served to eliminate these variables from influencing postoperative facial nerve outcomes. From an initial pool of 450 patients, 35 pairs of patients were matched for the study. Facial nerve functions were reported at immediate, 3-month, and 1-year postoperative periods. RESULTS: Patient demographics demonstrated that matched patients had almost identical tumor size, patient age, and date of operation. Comparisons of postoperative facial nerve functions between the matched groups revealed that retrosigmoid approach carried 2.86 times higher risk of facial nerve dysfunction during the immediate postoperative period. However, by 1 year, the facial nerve outcomes were similar between the two groups. CONCLUSION: Compared with the translabyrinthine approach, retrosigmoid approach carries a higher risk of postoperative facial nerve dysfunction during the immediate postoperative period. However, long-term facial nerve outcomes are identical between the two approaches.     

Endolymphatic duct violation during retrosigmoid dissection of the internal auditory canal: a human temporal bone radiographic study

OBJECTIVE/HYPOTHESIS: Successful hearing preservation after acoustic neuroma resection is sometimes complicated by delayed hearing deterioration. The goal of this study was to investigate the hypothesis that internal auditory canal (IAC) drilling during retrosigmoid acoustic neuroma removal may result in endolymphatic duct (ELD) injury, a potential cause of delayed hearing loss (HL) after hearing preservation surgery. STUDY DESIGN: Temporal bone anatomic and radiographic study and literature review. METHODS: Twenty-one human temporal bones were analyzed with high-resolution multislice computed tomography (HRMCT) and subjected to standard retrosigmoid IAC dissection with labyrinthine preservation and follow-up HRMCT for analyses of the ELD. A MEDLINE search was performed of studies documenting long-term hearing preservation outcomes after retrosigmoid dissection. RESULTS: Five of 21 (24%) bones were found to have violation of the ELD despite preservation of labyrinthine structures and the endolymphatic sac. These results correlate with the mean incidence of long-term hearing decline (26.6%). Reviews of human and animal studies indicate that injury to the ELD may create endolymphatic hydrops. CONCLUSIONS: The ELD is vulnerable to injury during IAC dissection even if labyrinthine structures at the lateral aspect of the IAC are preserved. These findings may be helpful in explaining and potentially preventing some cases of long-term hearing deterioration that may be a result of endolymphatic hydrops after ELD injury during acoustic tumor removal. Careful preoperative review of imaging studies using HRMCT may prove useful before retrosigmoid dissection.     

Retrosigmoid versus middle fossa surgery for small vestibular schwannomas

OBJECTIVES/HYPOTHESIS: The objective was to determine the effect of approach, middle fossa versus retrosigmoid, on the hearing and facial nerve outcome of surgery for small vestibular schwannomas. STUDY DESIGN: The study had two parts, a case study of patient data entered into a prospectively designed database at the author's institution, and a meta-analysis of similar published data. METHODS: There were 73 of the author's private practice patients who met the inclusion criteria of intracanalicular vestibular schwannoma and total tumor removal by a retrosigmoid approach. American Academy of Otolaryngology-Head and Neck Surgery standardized hearing and facial nerve classifications of these patients and similar data from 11 other institutions were used to compare results of the two surgical approaches. RESULTS: Median facial nerve results for all institutions were significantly better with the retrosigmoid approach (grade I: 95% for retrosigmoid and 81% for middle fossa). Median hearing results trended toward better outcome with the middle fossa approach (same preoperative hearing class: 48% for middle fossa and 39% for retrosigmoid). Individual institution had an equal or greater effect on outcome than the choice of surgical approach. CONCLUSION: Surgical team accounted for more variability in hearing and facial nerve outcome than did approach. Retrosigmoid approach yielded significantly better facial nerve outcome. The trend toward better hearing outcome with the middle fossa approach may never achieve statistical significance across institutions because of high variability among surgical teams and small numbers of teams reporting results.