A posterolateral approach to the skull base: the petro-occipital transsigmoid approach

Surgical management of chondrosarcomas of the skull-base and temporal bone

OBJECTIVES

To analyze the overall long-term outcome of surgically treated skull base and temporal bone chondrosarcomas.

METHODS

The medical records of patients with surgically treated skull base and temporal bone chondrosarcomas between 1983 and 2024 were thoroughly evaluated.

RESULTS

Out of a total of over 5000 skull base surgeries performed at our center, only 29 patients had histopathologically confirmed chondrosarcomas of the skull base and temporal bone. The mean of patients age was 45.6, and the male-to-female ratio was 1.9:1. The most common symptoms included hearing loss (58.6%), tinnitus (41.4%), diplopia (31%), dysphonia (24.1%), dysphagia (20.7%), vertigo (10.3%), and dizziness (10.3%). The most frequent locations of lesions among the 29 patients are as follows: petroclival region (34.5%), jugular foramen (27.6%), petrous apex (17.2%), middle ear (13.8%), others (3.4%). TO, IFTA, IFTB, IFTC, POTS, and combined surgical approaches were commonly used. The rate of gross total removal and recurrence was 82.6% and 13.8% respectively. The follow-up duration of 6 patients was more than five years and less than ten years whereas ten patients had more than ten years of follow-up.

CONCLUSIONS

Chondrosarcoma of the skull base and temporal bone is a very rare pathology. Due to its multiple potential sites of origin and histological specificity, it presents us with significant challenges. Gross total removal is the primary treatment for chondrosarcoma of the skull base and temporal bone. Personalized decision-making should be considered based on the following aspects: tumor, patient, and surgeon's factors. Postoperative radiation therapy is complementary to surgical treatment in grades II and III lesions to achieve long-term survival.

Gruppo Otologico's Experience in Managing the So-Called Inoperable Tympanojugular Paraganglioma

Objective: to identify advanced or "so-called inoperable" cases of tympanojugular paragangliomas (PGLs) and analyze how each case is surgically managed and followed afterward. Study Design: a retrospective case series study. Methods: Out of 262 type C and D TJPs and more than 10 cases of advanced or so-called inoperable cases, files of 6 patients with a diagnosis of advanced tympanojugular PGLs who were referred to an otology and skull-base center between 1996 and 2021 were reviewed to analyze management and surgical outcomes. The criteria for choosing these cases involve having one or more of the following features: (1) a large-sized tumor; (2) a single ipsilateral internal carotid artery (ICA); (3) involvement of the vertebral artery; (4) a considerable involvement of the ICA; (5) an extension to the clivus, foramen magnum, and cavernous sinus; (6) large intradural involvement (IDE); and (7) bilateral or multiple PGLs. Results: The age range at presentation was 25-43 years old, with a mean of 40.5 years: two females and four males. The presenting symptoms were glossal atrophy, hearing loss, pulsatile tinnitus, dysphonia, shoulder weakness, and diplopia. The modified Infratemporal Fossa Approach (ITFA) with a transcondylar-transtubercular extension is the principal approach in most cases, with additional approaches being used accordingly. Conclusions: The contemporary introduction of carotid artery stenting with the direct and indirect embolization of PGLs has made it possible to operate on many cases, which was otherwise considered impossible to treat surgically. Generally, the key is to stage the removal of the tumor in multiple stages during the management of complex PGLs to decrease surgical morbidities. A crucial aspect is to centralize the treatment of PGLs in referral centers with experienced surgeons who are trained to plan the stages and manage possible surgical complications.

Clivus Chordoma: Case Report and Current Considerations on Treatment Strategies

Chordomas are the rare malignant bone lesions derived from the embryonic notochord. They are slow-growing tumors with a locally aggressive behavior. The clival chordomas are extradural, exophytic, and lytic lesions centered on the clivus, and are managed differently from those arising elsewhere because of the emphasis on preserving the neurological function. The gold standard for therapy is the complete resection followed by radiation therapy for a better local control of the tumor. This case report concerns a 20-year old girl with an incidental diagnosis of the clival chordoma, which was first treated via an endoscopic anterior approach to remove the exophytic portion of the tumor. The adjuvant radiation therapy was not feasible because of the macroscopic intradural residual tumor being at the level of jugular foramen. The girl was referred to our institute for the removal of the intradural residual tumor via a petro-occipital trans-sigmoid (POTS) approach followed by adjuvant proton beam therapy. The choice of the surgical approach depends on the size of the tumor, its location, and its anatomical distribution, but should also be balanced against the morbidity, considering the patient's age, and the feasibility of postoperative rehabilitation.

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

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

Transjugular transsigmoid approach for triple dumbbell-shaped jugular foramen schwannomas

BACKGROUND

Jugular foramen tumors, particularly those that are triple dumbbell-shaped with intracranial, intraforaminal, and extracranial extensions, are difficult to access surgically. However, advances in neuroimaging, neuromonitoring, and skull base surgery have enabled their safe resection with lower rates of morbidity and mortality.

METHOD

We share our experience with the surgical technique for the management of triple dumbbell-shaped jugular foramen schwannomas.

CONCLUSION

The infralabyrinthine transjugular transsigmoid approach with high cervical exposure under continuous vagus nerve monitoring enables gross total resection of triple dumbbell-shaped jugular foramen schwannomas, aiming at surgical cure of these benign tumors for appropriately selected patients.

Microsurgical Anatomy of the Jugular Process as an Anatomical Landmark to Access the Jugular Foramen: A Cadaveric and Radiological Study

BACKGROUND

The jugular process forms the posteroinferior surface of the jugular foramen and is an important structure for surgical approaches to the foramen. However, its morphological features have not been well described in modern texts.

OBJECTIVE

To elucidate the microsurgical anatomy of the jugular process and examine its morphological features.

METHODS

Five adult cadaveric specimens were dissected in a cadaveric study, and computed tomography data from 31 heads (62 sides) were examined using OsiriX (Pixmeo SARL, Bernex, Switzerland) to elucidate the morphological features of the jugular process.

RESULTS

The cadaveric study showed that it has a close relationship with the sigmoid sinus, jugular bulb, rectus capitis lateralis, lateral atlanto-occipital ligament, and lateral and posterior condylar veins. The radiographic study showed that 9/62 sigmoid sinuses protruded inferiorly into the jugular process and that in 5/62 sides, this process was pneumatized. At the entry of the jugular foramen, if the temporal bone has a bulb-type jugular bulb, and if surgery concerns the right side of the head, the superior surface of the jugular process is more likely to be steep.

CONCLUSION

The jugular process forms the posteroinferior border of the jugular foramen. Resection of the jugular process is a critical step for opening the jugular foramen from the posterior and lateral aspects. Understanding the morphological features of the jugular process, and preoperative and radiographical examination of this process thus help skull base surgeons to access the jugular foramen.

Bilateral chondrosarcoma of the jugular foramen: literature review and personal experience

Chondrosarcomas (CS) are slow-growing malignant cartilaginous tumors with locally invasive behavior. They account for only 0.15% head and neck neoplasia. There have been no reports in the management of bilateral skull base CS in the literature to date. The synchronous presentation of bilateral CS of the jugular foramen (JF) was diagnosed in a 22-year-old woman with right abducens nerve palsy. Once evaluated the collateral intracranial venous discharge, the lesions were removed in two surgical stages through a bilateral petro-occipital trans-sigmoid (POTS) approach performing a bilateral closure of sigmoid sinus. The patient is disease free 15 years after surgery. No complications occurred. Diplopia improved after excision of the tumor on the right side. A review of relevant English literature was performed. The POTS approach to the JF proved to be safe and effective. Staged radical surgery alone, assessing intracranial venous flow at all stages of surgery, was a valid strategy for bilateral CS, achieving long-term disease control, avoiding early adjuvant radiotherapy, and carrying no complications.

Microsurgical and Endoscopic Anatomy of the Extended Retrosigmoid Inframeatal Infratemporal Approach

BACKGROUND

Different and often complex routes are available to deal with jugular foramen tumors with extracranial extension.

OBJECTIVE

To describe a novel extension of the retrosigmoid approach useful to expose the extracranial area abutting the posterior fossa skull base.

METHODS

A navigation-guided, endoscope-assisted retrosigmoid inframeatal approach was performed on 6 cadaveric heads in the semisitting position, displaying an area from the internal acoustic meatus to the lower cranial nerves and exposing the intrapetrous internal carotid artery. We then continued removing the temporal bone located between the sigmoid sinus and the hearing apparatus, reaching the infratemporal area just lateral to the jugular fossa. This drilling, which we refer to as posterolateral inframeatal drilling, has not previously been described. Drilling of the horizontal segment of the occipital squama allowed good visualization of the uppermost cervical internal carotid artery, internal jugular vein, and lower extracranial cranial nerves.

RESULTS

We were able to provide excellent exposure of the inframeatal area and of the posterior infratemporal fossa from different operative angles, preserving the neurovascular structures and the labyrinth in all specimens. The intradural operative window on the extracranial compartment was limited by the venous sinuses and the hearing apparatus and presented a mean width of 8.52 mm. Sigmoid sinus transection led to better visualization of the lateral half of the jugular foramen and of the uppermost cervical internal carotid artery.

CONCLUSION

The navigation-guided endoscope-assisted extended retrosigmoid inframeatal infratemporal approach provides an efficient and versatile route for resection of jugular foramen tumors with extracranial extension.

Suprajugular extension of the retrosigmoid approach: microsurgical anatomy

Object

Jugular foramen tumors often extend intra- and extracranially. The gross-total removal of tumors located both intracranially and intraforaminally is technically challenging and often requires a combined skull base approach. This study presents a suprajugular extension of the retrosigmoid approach directed through the osseous roof of the jugular foramen that allows the removal of tumors located in the cerebellopontine angle with extension into the upper part of the foramen, with demonstration of an illustrative case.

Methods

The cerebellopontine angles and jugular foramina were examined in dry skulls and cadaveric heads to clarify the microsurgical anatomy around the jugular foramen and to define the steps of the suprajugular exposure.

Results

The area drilled in the suprajugular approach is inferior to the acoustic meatus, medial to the endolymphatic depression and surrounding the superior half of the glossopharyngeal dural fold. Opening this area exposed the upper part of the jugular foramen and extended the exposure along the glossopharyngeal nerve below the roof of the jugular foramen. In the illustrative case, a schwannoma originating from the glossopharyngeal nerve in the cerebellopontine angle and extending below the roof of the jugular foramen and above the jugular bulb was totally removed without any postoperative complications.

Conclusions

The suprajugular extension of the retrosigmoid approach will permit removal of tumors located predominantly in the cerebellopontine angle but also extending into the upper part of the jugular foramen without any additional skull base approaches.

Skull base chondrosarcomas: surgical treatment and results

OBJECTIVES

We describe our experience in the management of patients with skull base chondrosarcoma, an uncommon neoplasm of the skull base.

METHODS

Thirteen cases of surgically treated skull base chondrosarcomas were identified. The patients' follow-ups ranged from 7 to 86 months (mean, 47 months).

RESULTS

The most common tumor locations were the jugular foramen (5 cases), the petrous apex (3 cases), and the petroclival region (3 cases). An infratemporal fossa type A approach was performed in 2 cases, and 2 patients underwent an infratemporal fossa type B approach. Two patients underwent a transotic approach, 1 patient underwent a petro-occipital transsigmoid approach, and a petro-occipital transsigmoid approach combined with a transotic approach was chosen in 1 case. One patient underwent an infratemporal fossa type C approach combined with a transotic approach, and 2 patients underwent an infratemporal fossa type B approach combined with a transotic approach. One patient underwent an infratemporal fossa type B approach combined with a transzygomatic approach, and the last patient underwent a transmastoid approach. Gross total tumor removal was achieved in all patients. Postoperative radiotherapy was performed in 7 cases. The most common complications were lower cranial nerve deficits. Two patients experienced recurrences, 36 months and 6 years after surgical removal.

CONCLUSIONS

We believe that the primary treatment for chondrosarcomas of the skull base is gross total surgical resection. We usually do not recommend radiotherapy as the primary treatment for patients with skull base chondrosarcomas; however, radiotherapy may be considered as an alternative primary treatment in selected cases in which there are serious medical contraindications to surgery, as well as in elderly patients. We reserve postoperative radiotherapy for patients with histologically aggressive tumors (grade II or III), as well as for cases of subtotal resection or recurrent tumors.

Lateral approaches to the skull base

Progress in the study of skull base anatomy and the different lesions involving it has led to more and more precise knowledge of the site. New diagnostic tools have allowed better definition of various diseases, and the use of an operative microscope and modern surgical instruments have all contributed to the development of microsurgery of the skull base. Refinements in microsurgical techniques have led to the description of multiple approaches to the skull base. Lateral approaches to the skull base have been described by pioneering surgeons who created the basis of this surgery and further contributed with their own experience. Refinements and modifications to the original technique have taken place over years, to the point that nowadays the large number of approaches described by oto- and neurosurgeons have led to some confusion. We have attempted to simplify this by retracing it to the original, basic steps based on the most representative publications and personal experience.

The petro-occipital trans-sigmoid approach for lesions of the jugular foramen

This study's goals were twofold: (1) to analyze the author's experience with the petro-occipital trans-sigmoid (POTS) approach for the resection of tumors arising in or adjacent to the jugular foramen, and (2) to define the anatomical sites exposed by this approach. A retrospective review was conducted of 61 patients with jugular fossa tumors that included lower cranial nerve schwannomas, paragangliomas, meningiomas, chordomas, cholesteatomas, and other benign or low-grade malignant tumors. Outcome measures were mortality, morbidity, and long-term outcomes. No deaths were found in this study. The major morbidity was deficits of the glossopharyngeal, vagus, and accessory nerves. Hearing and facial nerve function were largely preserved. The resections were undertaken as single-stage procedures regardless of whether the tumor was entirely extradural or both intra- and extradural. None of the patients had central nervous system complications. Good outcomes were achieved for schwannomas, meningiomas, chondrosarcomas, and papillary adenoma. Chordomas tended to recur, and only class C1 paragangliomas could be removed using this approach. The study found that the POTS approach should be considered the approach of choice for many tumors in the region of the jugular foramen, particularly schwannomas. It is not suitable for the resection of malignant tumors and most paragangliomas because it offers limited access to the skull base between the jugular fossa and carotid canal.

Nonvascular lesions of the jugular foramen: the gruppo otologico experience

Tumors other than paragangliomas in the jugular foramen are uncommon. Of these, schwannomas and meningiomas predominate. Little clinical data are available in the literature on these tumors at this site. The purpose of this article is to review our experience at the Gruppo Otologico of the management of these tumors. A retrospective series is presented of 32 consecutive patients affected by jugular foramen schwannomas and meningiomas in which their clinical and radiological signs, together with surgical techniques and outcomes, were reviewed. A single-stage resection was possible for the majority of patients when the petro-occipital trans-sigmoid (POTS) approach was used. This allowed resection of both intra- and extradural components of the tumor with hearing preservation and avoidance of facial nerve transposition. No deaths occurred. Lower cranial nerve palsies constituted the major cause of morbidity, but none of the patients required an adjunctive procedure such as vocal cord medialization, tracheostomy, or percutaneous gastrostomy.

Surgical Management of Jugular Foramen Meningiomas: A Series of 13 Cases and Review of the Literature

OBJECTIVE

Primary meningiomas occurring within the jugular foramen are exceedingly rare lesions presumed to originate from arachnoid-lining cells situated within the jugular foramen. The objective of this study is to analyze the management and outcome in a series of 13 primary jugular foramen meningiomas collected at a single center.

STUDY DESIGN

Retrospective study.

SETTING

Quaternary referral otology and skull base private center.

METHODS

Charts belonging to 13 consecutive patients with pathologically confirmed jugular foramen meningioma surgically treated between September 1991 and May 2005 were examined retrospectively. The follow-up of the series ranged from 12 to 120 (mean, 42.8 +/- 27.5) months.

RESULTS

Four (28.5%) patients underwent single-stage tumor removal through the petro-occipital transigmoid (POTS) approach. In two patients with preoperative unserviceable hearing, a combined POTS-translabyrinthine approach was adopted. Two patients underwent a combined POTS-transotic approach because of massive erosion of the carotid canal. A modified transcochlear approach type D with posterior rerouting of the facial nerve and transection of the sigmoid sinus and jugular bulb was performed in two patients with a huge cerebellopontine angle tumor component with extension to the prepontine cistern together with massive involvement of the petrous bone and middle ear and encasement of the vertical and horizontal segments of the intrapetrous carotid artery. In one patient with evidence of a dominant sinus on the site of the tumor, a subtotal tumor removal via an enlarged translabyrinthine approach (ETLA) was planned to resect the intradural component of the tumor. Two patients in our series underwent a planned staged procedure on account of a huge tumor component in the neck. One of these patients underwent a first-stage infratemporal fossa approach type A to remove the tumor component in the neck; the second-stage intradural removal of the tumor was accomplished via an ETLA. The last patient underwent a first-stage modified transcochlear type D approach to remove the intradural tumor component followed by a second-stage transcervical procedure for removal of the extracranial component. Gross total tumor removal (Simpson grade I-II) was achieved in 11 (84.6%) cases. Subtotal removal of the tumor was accomplished in two patients. Good facial nerve function (grades I and II) was achieved in 46.1% of cases, whereas acceptable function (grade III) was achieved in the remaining cases 1 year after tumor removal. Hearing was preserved at the preoperative level in all four patients who underwent surgery via the POTS approach. After surgery, no patient recovered function of the preoperatively paralyzed lower cranial nerves. A new deficit of one or more of the lower cranial nerves was recorded in 61.5% of cases.

CONCLUSIONS

Surgical resection is the treatment of choice for jugular foramen meningiomas. Among the various surgical techniques proposed for dealing with these lesions, we prefer the POTS approach alone or combined with the translabyrinthine or transotic approaches. Despite the advances in skull base surgery, new postoperative lower cranial nerve deficits still represent a challenge.

Vagal paraganglioma

OBJECTIVES

To report the outcomes of surgical treatment of vagal paragangliomas and to define a management protocol.

DESIGN

A retrospective case series.

PATIENTS AND METHODS

Sixteen consecutive patients with vagal paragangliomas managed by surgical resection using a cervicoparotid approach and pericapsular dissection using microsurgical techniques between 1990 and 2003.

RESULTS

All patients either had or developed a vagal palsy. Additional cranial nerve deficits were sustained in 8 patients. No patients died as a result of surgery or from their disease.

CONCLUSIONS

The technique used and described in this article allowed adequate exposure of the retrostyloid parapharyngeal space for the safe removal of all vagal tumors in this series. Careful consideration must be given to the likely natural progression of these tumors before committing to surgical resection. This is particularly important in patients with multifocal disease.

Surgical Management of Jugular Foramen Schwannomas With Hearing and Facial Nerve Function Preservation: A Series of 23 Cases and Review of the Literature

OBJECTIVE

Schwannomas of the jugular foramen are rare lesions and controversy regarding their management still exists. The objective of this retrospective study was to analyze the management and outcome in a series of 23 cases collected at a single center.

SETTING

This study was conducted at a quaternary private otology and skull base center.

METHODS

Charts belonging to patients with a diagnosis of jugular foramen schwannoma attending our center between May 1988 and April 2006 were examined retrospectively.

RESULTS

The study group consisted of 23 patients. One patient (a 73-year-old woman) with normal lower cranial nerves function was managed with watchful expectancy and regular clinical and radiologic follow ups. The infratemporal fossa approach-type A (IFTA-A) was performed in 3 cases. One patient underwent a transcochlear-transjugular approach. Of the 22 patients surgically treated, 12 patients were operated on by the petrooccipital transsigmoid approach (POTS). In one patient with a preoperative dead ear, a combined POTS-translabyrinthine approach was adopted. Two patients were operated on through the POTS approach combined with the transotic approach. In another case (a 67-year-old woman), a subtotal tumor removal through a transcervical approach was planned to resect a 10-cm mass in the neck. One patient underwent a first-stage combined transcervical-subtotal petrosectomy approach to remove a huge tumor in the neck; the second-stage intradural removal of the tumor was accomplished through a translabyrinthine-transsigmoid-transjugular approach. The last patient underwent a first-stage combined transcervical-subtotal petrosectomy approach to remove the neck tumor component; this patient is now waiting for the second-stage intradural removal of the tumor. Complete tumor removal was accomplished in 21 cases and in one case, a residual schwannoma was left in place in the area of the jugular foramen. The 3 patients who were operated on by IFTA-A underwent permanent anterior transposition of the facial nerve. At 1-year follow up, 2 of these patients had House-Brackmann grade I and 1 reached grade IV. The patient who underwent a transcochlear-transjugular approach had a permanent posterior transposition of the facial nerve. At 1-year follow up, he had grade III facial nerve function. Postoperative facial nerve function was normal (House-Brackmann grade I) in all patients operated on by the POTS approach. Twelve patients had hearing-preserving surgery using the POTS approach. Good hearing was preserved in 10 cases (83.3%), the majority of whom (58.3%) maintained their preoperative hearing level. There was no perioperative mortality. One patient (4.5%) experienced a postoperative cerebrospinal fluid leak. After surgery, all patients did not recover the function of the preoperatively paralyzed lower cranial nerves. A new deficit of one or more of the lower cranial nerves was recorded in 50% of cases. So far, no patient has experienced recurrence during the follow-up period as ascertained by computed tomography or magnetic resonance imaging.

CONCLUSIONS

Surgical resection is the treatment of choice for jugular foramen schwannomas. The POTS approach allowed single-stage, total tumor removal with preservation of the facial nerve and of the middle and inner ear functions in the majority of cases. Despite the advances in skull base surgery, new postoperative lower cranial nerve deficits still represent a challenge.

Lower cranial nerve schwannomas involving the jugular foramen

Schwannomas involving the jugular foramen are rare lesions, and no consensus exists on their management. This paper reports on 20 such cases treated in our centers. Nineteen cases were operated on for removal of the tumors, and the remaining case is being managed by watchful expectancy. Fifteen cases were operated on by the petro-occipital trans-sigmoid approach with or without labyrinthectomy, 2 by the infratemporal fossa approach, 1 by the modified transcochlear approach, and 1 by the jugulo-petrosectomy approach. The petro-occipital trans-sigmoid approach allowed single-stage, total tumor removal with preservation of the facial nerve and of middle and inner ear functions. Lower cranial nerve paralysis was the major complication and seemed to be inherent to the disease rather than to the approach used. No cerebrospinal fluid leak or meningitis occurred in the present series. So far, no recurrence has been detected.

The widened retrolabyrinthe approach: a new concept in acoustic neuroma surgery

For many years, the retrolabyrinthine approach has been limited to functional surgery of the cerebellopontine angle (CPA). As a result of the increased surgical exposure, particularly the opening of the internal auditory meatus (IAM), the widened retrolabyrinthine technique permits tumor excision from both the CPA and the IAM, regardless of the histological nature of the tumor. The authors have treated 60 acoustic neuromas of varying sizes via this approach (6% intrameatal tumors; 30% > 25 mm in diameter). The postoperative mortality rate was 0%. The risk of fistula formation was 3.3%, and 3.3% of the patients suffered from postoperative meningitis. The results for facial nerve function were equivalent to those obtained previously via a widened translabyrinthine approach and those in a series treated via a suboccipital approach (80% with Grades I and II, 15% with Grade III, and 5% with Grades V and VI). One patient (1.7%) required a secondary hypoglossal-facial nerve anastomosis and had attained a Grade IV result 6 months later. Postoperatively 21.7% of these patients maintained socially useful hearing and 20% had mediocre hearing. Socially useful hearing was preserved in 50% of a subgroup of 20 patients who had both good preoperative hearing and a tumor that involved less than half of the IAM regardless of its volume. Additionally, 15% had mediocre hearing that could be improved with hearing aids. Because of its efficacy in preserving hearing, the authors favor the retrolabyrinthine over the occipital approach, with the latter being considered less subtle and more aggressive.