Hearing preservation in conservation surgery for vestibular schwannoma

OBJECTIVE: To evaluate preservation of hearing in the resection of vestibular schwannomas. STUDY DESIGN: A retrospective case review. SETTING: Tertiary-care medical center. PATIENTS: Forty-seven patients (25 men, 22 women) were studied; mean age was 46 years, mean tumor diameter 9.8 mm (range 3-30 mm.) INTERVENTIONS: All patients underwent resection of vestibular schwannomas by the middle cranial fossa (MCF) or the retrosigmoid (RS) approach. MAIN OUTCOME MEASURES: Hearing preservation was classified by the criteria outlined by the American Academy of Otolaryngology-Head Neck Surgery. Hearing was assessed preoperatively and postoperatively at 1 month and 1 year. Facial function was graded according to the House-Brackmann scale. Minimum follow-up was 18 months. RESULTS: Hearing was preserved in 69% of patients who underwent the MCF approach but in only 33% of patients for whom the RS approach was used. The RS approach was used for larger tumors (mean diameter 15 mm) and the MCF procedure for smaller tumors (mean diameter 9 mm). One hundred percent of patients had facial function H/B grade II or better, regardless of approach. CONCLUSION: Hearing function can be reliably preserved in a high percentage of selected patients undergoing resection of vestibular schwannoma.     

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.     

Nerve of origin, tumor size, hearing preservation, and facial nerve outcomes in 359 vestibular schwannoma resections at a tertiary care academic center

Objective: To determine nerve of origin, tumor size, hearing preservation rates, and facial nerve outcomes in a retrospective cohort study of patients undergoing translabyrinthine (TL), middle cranial fossa (MCF), and retrosigmoid/suboccipital (SO) approaches to vestibular schwannomas (VS). Study Design: Retrospective. Methods: Chart review. Results: Patient charts from 231 TL, 70 MCF, 53 SO, and 5 combined TL/SO procedures for VS were evaluated in 356 patients. The inferior vestibular nerve (IVN) was the nerve of origin in 84 of 359 cases (23.3%), while the superior vestibular nerve (SVN) was the nerve of origin in 36 patients (10%). In 239 of 359 cases (66.6%), the nerve of origin was not identified. Forty patients undergoing hearing preservation surgery had hearing results and nerve of origin data available for review. Functional hearing (<50dB PTA and >50% speech discrimination) was preserved in 10 of 15 patients (75%) with SVN tumors, while only 7 of 25 patients (28%) with IVN tumors retained functional hearing. Facial nerve outcomes and nerve of origin were recorded simultaneously in 109 patients. Seventy‐one of 74 patients (95%) patients with IVN tumors achieved a House‐Brackmann (HB) grade I–III, while 35 of 35 patients (100%) with SVN tumors retained HB I–III facial function. Looking at tumor size versus hearing preservation, functional hearing was preserved in 22 of 49 patients (45%) with <1‐cm tumors, and 4 of 20 patients (20%) with 1‐ to 1.5‐cm tumors. For all cases with documented facial nerve function, HB I–III were achieved in 96% of SO, 94% of MCF, and 88% of TL procedures. Conclusions: Our retrospective data indicated that IVN tumors were twice as common as SVN tumors. The nerve of origin did not affect facial nerve outcomes but did impact hearing preservation rates. Patients with tumors <1 cm in size had the best chance for hearing preservation. Overall facial nerve preservation was excellent with >90% achieving HB 1 to 3 function at final follow‐up.     

Middle fossa acoustic tumor surgery: results in 106 cases

Although the middle cranial fossa approach has been used less frequently in recent years than in the past, it continues to be a useful technique for the removal of small acoustic tumors with possible hearing preservation. The approach provides complete exposure of the contents of the internal auditory canal, thus allowing positive facial nerve identification and facilitating total tumor removal. This paper reports the results of 106 middle fossa acoustic tumor removals over a 25-year period. Measurable postoperative hearing remained in 59% of cases. In 89% of cases, normal or near-normal postoperative facial nerve function was obtained. Total tumor removal was achieved in 98% of cases. Preoperative selection criteria are discussed, and postoperative complications are reported.     

Middle fossa approach for acoustic tumor removal.

The middle fossa approach is well suited for the removal of small acoustic tumors with possible hearing preservation. The most appropriate candidates have tumors with less than 5 mm extension into the cerebellopontine angle and good preoperative hearing (speech reception threshold less than or equal to 30 dB, speech discrimination score greater than or equal to 70%). Measurable postoperative hearing can be preserved in 31% to 59% of patients, and normal or near normal facial function occurs in 86% to 89%. Serious postoperative complications are rare with this approach. With the advent of gadolinium-enhanced MRI, it is now possible to diagnose acoustic tumors reliably when small and before hearing has been significantly affected. The middle fossa approach provides excellent access for the removal of these small tumors.     

Facial nerve hemangioma of the geniculate ganglion: An endoscopic surgical approach

Facial nerve hemangiomas are rare benign tumors arising from the venous plexus surrounding the facial nerve. Surgical management of these tumors is controversial. The goal of surgery is complete tumor removal with restoration of facial nerve function and preservation of hearing, wherever possible. The approaches most used are the translabyrinthine and middle cranial fossa approaches. In this report, we describe the first facial hemangioma treated with an endoscopic transcanal approach, combined with a retroauricular transmastoid minicraniotomy for closure of the dural defect. A great auricular nerve graft was used to reconnect interrupted nerve segments. Histopathological examination confirmed the diagnosis of a hemangioma of the first genu of the facial nerve. With magnification of the structures, the transcanal endoscopic approach allowed a radical excision of the neoplasm permitting hearing function preservation, with the possibility to work with a minimally invasive approach with respect to the labyrinthine block and cochlea. Compared to a middle cranial fossa approach, the transcanal endoscopic approach avoided labyrinthine block removal and brain retraction.     

颞骨和颞下窝联合入路侧颅底肿瘤切除术

探讨安全和彻底摘除广侵侧颅底及其相邻区的肿瘤的手术入路和方法。方法通过颞骨和颞下窝联合入路,应用显微外科技术摘除肿瘤,并尽可能维护或重建颅底和颅神经。     

Results in otosurgically treated patients with acoustic neuroma. Part 2: Hearing results after middle fossa approach

BACKGROUND: The surgical therapy of acoustic neuromas has been seen critically lately. Alternative methods like the gamma-knife treatment open a wide field of discussion. PATIENTS: The results of 392 patients are presented operated on via a middle fossa approach between 1989 and 2004. RESULTS: Hearing preservation according to the 50 : 50 rule (hearing loss less than 50 dB in pure tone audiogram 500 - 1000 - 2000 Hz, speach discrimination > 50 %) was possible in 59.7 % of patients. A hearing impression up to 90 dB was recognized in 83.1 %, 16.9 % of cases were deaf. There was no difference between tumors confined to the inner ear canal and tumors extending into the cerebello pontine angle. There was also no difference between tumors up to a volume of 100 mm (3) and tumors between 100 mm(3) and 500 mm(3). CONCLUSION: Acoustic neuroma confined to the internal meatus or with little extend into the cerebello pontine angle (i. e. no contact to structures of the brain stem or vessels of the posterior fossa) are feasable for resection via the middle fossa approach. The possibility of hearing preservation and low morbidity makes it the treatment of choice for this group of tumors.     

Surgical management of previously untreated glomus jugulare tumors

The treatment of glomus jugulare tumors is controversial. Changes in the surgical treatment of glomus jugulare tumors at The House Ear Clinic have allowed complete resection in 85% of patients with minimal morbidity and no surgical mortalities. Our experience with 52 previously untreated patients with glomus jugulare tumors is reviewed. Two primary surgical techniques were used. The mastoid/neck approach was used in 9 patients with small tumors limited to the jugular bulb. The infratemporal fossa approach was used in the remaining 43 tumors. Lower cranial nerve preservation was possible in the majority of patients with normal preoperative function. Modifications in the management of the facial nerve during the infratemporal fossa approach have resulted in good recovery of facial function (House grade I/VI or II/VI) in 95% of patients. Most patients (85%) were able to fully resume all preoperative activities. Our results suggest that surgical management is the treatment of choice in younger patients with glomus jugulare tumors.     

Contemporary management of neurofibromatosis

The neurofibromatoses are two distinct entities with different genetic origins. The phenotypic expressions and required treatments are different. The devastating nature of neurofibromatosis-2 may be more effectively controlled through the application of advanced imaging techniques and contemporary neurotologic procedures. The most common manifestation of neurofibromatosis-2 is that of bilateral acoustic neuromas. The eventual total bilateral sensorineural deafness associated with this condition can be obviated in selected cases if the diagnosis is established early. Follow-up data are reported for three patients in whom hearing was preserved in at least one ear. When removal with hearing preservation is not possible, subtotal tumor removal with decompression of the internal auditory canals may delay progression of hearing loss. A new approach to tumors of the pterygomaxillary fossa that have extended to the middle cranial fossa has been successfully applied and is described.     

Hearing Preservation After Acoustic Neuroma Resection With Tumor Size Used As a Clinical Prognosticator

Three hundred sixty-four patients referred to the Chicago Otology Group for acoustic tumor removal between 1981 and 1995 were reviewed in a retrospective fashion. Of this group, 60 patients were candidates for hearing preservation surgery and thus underwent one of two surgical approaches to remove the tumor and preserve hearing. Eighteen patients had tumor removal via the middle cranial fossa approach, and 42 patients had tumor removed via the retrosigmoid approach. Of the 42 patients who underwent retrosigmoid removal, 33% had hearing preserved overall. Of the 18 patients in the middle fossa group, 44% had hearing preserved overall. The average tumor size of patients with preserved hearing in the retrosigmoid group was 1.4 cm, and in the middle fossa group was 0.74 cm. Of significance was the fact that in both groups of patients with a tumor of 1.5 cm or less there was a 50% chance of hearing preservation. In the group of patients with tumors larger than 1.5 cm there was only a 16% chance of preserving hearing. We propose that these data can be used for better counseling of patients preoperatively as to the chances of hearing preservation and the type of approach appropriate for each case.     

Facial function in hearing preservation acoustic neuroma surgery

OBJECTIVE: To determine if facial function is worse after hearing preservation acoustic neuroma surgery (retrosigmoid and middle fossa) than in translabyrinthine surgery. DESIGN: Retrospective medical record review. SETTING: Private neuro-otology subspecialty practice of patients operated on in a tertiary care hospital. PATIENTS: This study evaluated 315 consecutive acoustic neuroma surgical procedures between April 1989 and July 1998. A total of 209 translabyrinthine procedures and 106 hearing preservation surgical procedures were performed. The hearing preservation procedures were equally divided between retrosigmoid (n = 48) and middle fossa (n = 58) procedures. METHODS: Medical records were reviewed and tabulated for tumor size, surgical approach, and House-Brackmann facial function grade at short-, intermediate-, and long-term intervals. RESULTS: Postoperative facial function in hearing preservation surgical procedures at short- and long-term follow-up was not worse than facial function after translabyrinthine surgical procedures in comparably sized tumors. CONCLUSION: Concern about postoperative facial function should not be the deciding factor in selecting hearing preservation vs nonhearing preservation acoustic neuroma surgery.     

Facial nerve function after surgery for removal of acoustic neuroma by the extended middle cranial fossa approach

Postoperative facial nerve function was evaluated in 98 patients operated on by the middle cranial fossa approach or the extended middle cranial fossa approach from June 1976 to April 1985. In this series, the smaller the tumor size at the time of the initial surgery, the better the postoperative facial nerve function was. The facial nerve was preserved in 83.4% of the 79 patients who were subjected only to the initial surgery. However, total removal of the tumor along with facial nerve preservation was achieved only in 70.8%. Anatomical preservation of the facial nerve was possible in 78% of 87 patients. The postoperative functional results among patients in whom facial nerves were anatomically preserved were satisfactory (facial expression score of 75% or higher, i.e., 30 points or more out of a possible 40 points) in 70-80% of the patients with small size or intracanalicular tumors, but, in less than 50% of the patients with tumors of medium size or larger. There is a need to obtain higher rates of functional preservation as well as higher rates of satisfactory functional results. At the present stage, we must strive to achieve earlier diagnosis so that surgery can be performed while the tumor is still medium-sized or small.     

The middle fossa transpetrous approach to the anterior-superior cerebellopontine angle

We present a new approach to the skull base, medial and superior to the internal auditory canal, for tumors involving the anterior-superior cerebellopontine angle, petrous apex, and clivus. This approach is accomplished through a middle fossa craniotomy and involves removal of the bone anterior and medial to the internal auditory canal and medial to the cochlea and carotid artery. It combines the advantages of complete tumor removal, low mortality rate, and hearing preservation.     

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.     

Use of flexible CO<Subscript>2</Subscript> laser fiber in microsurgery for vestibular schwannoma via the middle cranial fossa approach

The aim of this study was to analyze the results of microsurgery in vestibular schwannomas (VS) with assistance of a flexible CO₂ laser fiber (Omniguide^®) using the middle cranial fossa (MCF) approach. For that purpose we performed a prospective non-randomized clinical trial. In 20 consecutive patients suffering from VS and elected for microsurgery via the MCF approach, tumor resection was performed with the aid of the flexible CO₂ laser (“laser group”, LG). Twenty patients with similar tumor volume and pre-operative hearing status out of a cohort of 76 patients previously treated by the same surgeon without laser were used as comparison group (“conventional group”, CG) (matched-pair-technique). Facial weakness (House-Brackmann (HB) 2-4) was seen in early postoperative (p.o.) days in six patients in each group and all recovered completely by 3 months p.o., except one patient with HB 2 in CG. Facial nerve preservation rate (HB 1 + 2) was 100% in both groups. Hearing preservation rate (Gardner/Robertson class 1 + 2 or AAO-HNS A + B, pre- and postoperatively) was 72% in LG and 82% in CG, without significant difference. Overall time from incision to skin suture was 157 min (SD 55.9) in CG and 160 min (SD 39.7) in LG. Tumor preparation time was 23.2 min (SD 19.7) in CG and 36.1 min (SD 33.8) in LG. The use of a handheld flexible CO₂ laser fiber in VS-microsurgery is safe and subjectively facilitates tumor resection especially in “difficult” (e.g., highly vascularized) tumors. However, in this limited prospective trial the excellent functional outcome following conventional microsurgery could not be further improved, nor the surgical time reduced by means of the non-contact laser-tool. Focusing the use of the flexible CO₂ laser on “difficult” tumors may lead to different results in future.     

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.     

Schwannoma of the pterygomaxillary fossa, excision by transmandibular approach

Primary tumors of the pterygomaxillary fossa are rare and difficult to approach surgically. A case of a schwannoma is reported, extirpation being through a transmandibular approach using an osteotomy-osteosynthesis procedure.     

The preauricular subtemporal approach for transcranial petrous apex tumors.

OBJECTIVE: To review our series of 51 patients with transcranial petrous apex tumors who were surgically managed through a preauricular subtemporal approach. STUDY DESIGN: A retrospective analysis of patient medical records. SETTING: Tertiary care academic medical center. PATIENTS: All patients with transcranial petrous apex tumors who were surgically treated between July 1988 and July 2005 with a preauricular subtemporal approach. INTERVENTION: The preauricular subtemporal approach with preservation of hearing was used in all 51 cases. MAIN OUTCOME MEASURES: The degree of tumor resection and long-term results. RESULTS: Total tumor resection was achieved in 45 patients, and tumor was left in the cavernous sinus in 6 cases. Magnetic resonance imaging surveillance revealed no recurrent tumor in 36 patients, stable residual disease in 5 cases, and regrowth of tumor in 10 individuals (mean follow-up, 8.8 yr). DISCUSSION: The postauricular infratemporal fossa approach allows adequate exposure to the petrous apex but with the expense of conductive hearing deficit. The preauricular subtemporal approach allows wide access for transcranial petrous apex tumors with preservation of hearing. Tumor control using this approach was achieved in 41 (80%) of 51 of the patients in this series.     

Evaluation of the results of endoscope-assisted acoustic neuroma surgery through posterior fossa approach

The objective of this study was to evaluate the results of endoscope-assisted acoustic neuroma surgery in posterior fossa approach. Between 1996 and 2002, 60 consecutive patients with acoustic neuroma were operated via the retrosigmoid suboccipital approach. Standard 4-mm sinus endoscopes at different angles were used during the surgeries either for inspection or tumor endoscopic dissection. Clinical parameters and treatment outcome were evaluated retrospectively. Tumor sizes were small, medium and large in 46.6, 45 and 8.3% of the patients, respectively. The hearing preservation rate, which did not correlate with tumor size (p > 0.05), was 24.4%. The need for facial reanimation surgery, which was needed in 5% of patients, was significantly higher in the large tumors than in the small and medium tumors (p < 0.001). Cerebrospinal fluid fistula rate, which was not related to tumor size (p > 0.05), was 13.3%. Tumor recurrence or residual tumor was not encountered at all. In conclusion, endoscopes give accurate information about the relationship between the tumor and the adjacent structures and help control the fundus of the internal auditory canal to ensure complete tumor removal. It is also helpful in visually verifying the continuity of the facial and cochlear nerves. The use of endoscopes does not appear to increase the hearing preservation rate, but is very helpful in complete tumor removal in the posterior fossa approach.