Lateral approaches to the median skull base through the petrous bone: the system of the modified transcochlear approach

Trends in the Management of Non-Vestibular Skull Base and Intracranial Schwannomas

The aim of this review is to analyze the latest trends in the management of non-vestibular skull base and intracranial schwannomas in order to optimize tumor control and quality of life. Non-vestibular cranial nerve schwannomas are rare lesions, representing 5–10% of cranial nerve schwannomas. Management decisions should be individualized depending on tumor size, location and associated functional deficits. Generally, large sized schwannomas exerting significant mass effect with increased intracranial pressure are treated surgically. In some cases, even after optimal skull base resection, it is not possible to achieve a gross total resection because tumor location and extent and/or to reduce morbidity. Thus, subtotal resection followed by stereotactic radiosurgery or fractioned radiotherapy offers an alternative approach. In certain cases, stereotactic radiosurgery or radiotherapy alone achieves good tumor control rates and less morbidity to gross total resection. Finally, given the slow growth rate of most of these tumors, observation with periodic radiographic follow-up approach is also a reasonable alternative for small tumors with few, if any, symptoms.

Endoscopic management of petrous apex cholesteatoma

We describe a technique for approaching petrous apex cholesteatoma using combined lateral microscopic/endoscopic approaches, and discuss the utility of endoscopy in managing matrix inside the petrous apex. In our two cases, total view inside the petrous apex was achieved under endoscopy without mobilizing the internal carotid artery, and the matrix was successfully removed. Neither patient has presented with postoperative recurrence thanks to the wide-angle endoscopic view inside the petrous apex. Since the number of patients was small, comparisons with microscopic treatments are not yet valid, but endoscopes could offer a helpful tool for operating inside the petrous apex.

Endoscope-assisted retrosigmoid infralabyrinthine approach to jugular foramen tumors

OBJECT

Removal of jugular foramen (JF) tumors usually requires extensive skull base approaches and is frequently associated with postoperative morbidities such as lower cranial nerve injury. The endoscope-assisted retrosigmoid infralabyrinthine approach is a relatively new approach to tumors extending into the bony canal of the JF. The authors present their experience with this approach.

METHODS

The endoscope-assisted retrosigmoid infralabyrinthine approach was used in 7 patients, including 5 with schwannomas and 2 with paragangliomas. The access to the tumor, extent of its removal, postoperative neurological outcome, and approach-related morbidities were evaluated.

RESULTS

Two patients had a history of previous partial tumor removal, and 1 was treated by embolization followed by two courses of Gamma Knife radiosurgery. In this latter patient near-total resection was achieved. Gross-total resection was possible in the remaining 6 patients. Five patients benefited from endoscopic assistance: in 2 patients it showed a tumor remnant after microscopic tumor removal, while in 3 patients it allowed safe removal of the intraforaminal tumor by visualizing the surrounding structures. No permanent neurological deficit was observed after the operation. Two patients presenting with swallowing disturbance had temporary postoperative worsening that improved later. One patient developed CSF leakage that was managed with a lumbar drain.

CONCLUSIONS

This study shows that the judicious application of the endoscope-assisted retrosigmoid infralabyrinthine approach is safe and effective for removal of the schwannomas extending into the JF and selected paragangliomas without significant luminal invasion of the sigmoid-jugular system.

Petroclival meningiomas resected via a combined transpetrosal approach: surgical outcomes in 60 cases and a new scoring system for clinical evaluation

OBJECT

Petroclival meningiomas are among the most challenging intracranial tumors to treat surgically. Many skull base approaches have been described to improve resection and decrease patient morbidity. The authors undertook this study to evaluate the results of their treatment of petroclival meningiomas using objective measurements of tumor volume and a new impairment scoring system to assess neurological symptoms that severely affect the patient's quality of life, such as impairment of swallowing and speaking, motor function, and consciousness and communication.

METHODS

Between January 1990 and December 2009, the authors used a combined transpetrosal approach to treat 60 patients with benign (WHO Grade I) petroclival meningiomas. In this retrospective study, all 60 cases were analyzed in detail with regard to tumor volume, extent of resection (EOR), long-term tumor control, neurological outcome, and the patient condition. In addition, patients were divided into 2 groups according to the period during which the surgery was performed: the early group, from 1990 to 1999, and the late group, from 2000 to 2009. A new scoring system, the petroclival meningioma impairment scale (PCMIS), was created for quantitative assessment of 8 categories of neurological functions, with scores assigned in each category according to the level of disability and its impact on the patient. The PCMIS was used preoperatively, at 3 months after surgery, and at the time of the last follow-up examination, and the results for the 2 groups were compared.

RESULTS

There were 24 cases in the early group (1990-1999), and the mean duration of follow-up was 149.3 months. The mean EOR was 96.1%, and good long-term tumor control was obtained in 22 patients (91.7%). One of patients died because of a postoperative complication in the perioperative period. The PCMIS improved in 3 patients (12.5%), remained stable in 1 (4.2%), and worsened in 20 (83.3%). There were 36 cases in the late group (2000-2009), and the mean duration of follow-up was 77.9 months. The mean EOR was 92.7%, and good long-term tumor control was obtained in 34 patients (94.4%). The PCMIS score improved in 23 patients (63.9%), remained stable in 5 (13.9%), and worsened in 8 (22.2%).

CONCLUSIONS

The combined transpetrosal approach has provided satisfactory functional improvements and excellent tumor control for patients with petroclival meningiomas. The PCMIS provides a specific tool for quantitative assessment of the patient's state.

Navigated minimally invasive presigmoidal suprabulbar infralabyrinthine approach to the jugular foramen without rerouting of the facial nerve

BACKGROUND

Jugular foramen tumors are rare and challenging lesions for skull base surgeons because of their difficult operative accessibility. Various surgical approaches to the jugular foramen have been described to overcome the morbidity of standard petrosectomy.

OBJECTIVE

To describe the surgical anatomy of a novel route to the jugular foramen without opening the fallopian canal, the navigated tailored presigmoidal suprabulbar infralabyrinthine approach.

METHODS

Ten cadaver heads were dissected under navigational guidance on both sides to examine the advantages and limitations of the presigmoidal suprabulbar infralabyrinthine approach without opening the fallopian canal. Mastoidectomy was performed by using a high-speed drill. Under navigation guidance, the sigmoid sinus, jugular bulb, posterior semicircular canal, and fallopian canal were located and preserved. The jugular foramen with the extradural part of the IXth, Xth, and XIth nerve were identified.

RESULTS

Measurements of the surgical corridor and exposed petrous bone area on high-resolution computed tomography showed that the navigated presigmoidal suprabulbar infralabyrinthine approach without opening the fallopian canal is a suitable route for extradural jugular foramen lesions with limited extension (approach height 5.59 ± 0.16 mm; approach width 7.68 ± 0.18 mm; approach surface 33.73 ± 1.37 mm; approach depth 32.92 ± 0.21 mm; vertical angle α of the surgical approach 41.3° ± 0.9°; horizontal angle β of the surgical approach 40.5° ± 0.6°).

CONCLUSION

The navigation-guided presigmoidal suprabulbar infralabyrinthine approach is a minimally invasive approach for selected lesions of the jugular foramen with preservation of the fallopian canal, labyrinthine block, and sigmoid sinus. This approach is suited for C1, De1, De2, Di1, and Di2 tumors according to the Fisch classification.

Oncologic outcome in surgical management of jugular paraganglioma and factors influencing outcomes

BACKGROUND

The purpose of this study was to identify the factors that may influence the management outcome in patients with jugular paragangliomas.

METHODS

The surgical records of 121 cases of jugular paraganglioma (Fisch classifications C and D) were reviewed.

RESULTS

The average follow-up was 88 months. Intracranial extension (ICE; Fisch classification De and Di) constitutes 55.4% of the cases. Two cases had a malignant jugular paraganglioma. Complete tumor resection was achieved in 81.8% of the cases, and there was evidence of recurrence in 4.0% from this group. Surgical tumor control was achieved in 96% of cases. Perioperative complications consisted mainly of cerebrospinal fluid leakage in 1.6% of the cases. The lower cranial nerve (CN) was preserved in 63% of the patients mainly in the cases without ICE.

CONCLUSION

The infratemporal fossa approach type A allows for complete tumor resection with low perioperative morbidity and recurrence rates. The significant influential factors were the severity of ICE and internal carotid artery involvement.

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.

Management of complex cases of petrous bone cholesteatoma

OBJECTIVES

In a retrospective analysis of a quaternary referral neuro-otologic private practice, we identify complex cases of petrous bone cholesteatoma (i.e., cases with encasement of vital structures such as the internal carotid artery, jugular bulb, and sigmoid sinus, with further extension to the clivus, sphenoid sinus, or rhinopharynx), review surgical approaches and techniques of management of vital structures, and propose the ideal surgical management.

METHODS

We performed a retrospective case study of 130 cases of petrous bone cholesteatoma submitted to surgery between 1979 and 2009 to identify the complex cases and their classification, approach used, outcomes, and recurrences.

RESULTS

Of 130 cases. 13 were complex. Facial palsy was the presenting feature in 11 cases, 7 of which presented with grade VI palsy. A long duration of facial palsy (more than 3 years) was seen in 5 cases. Clival involvement was seen in 6 cases; 1 case extended to the sphenoid sinus, and 1 to the rhinopharynx. The internal carotid artery was encased in 11 cases in the vertical and the horizontal parts. The jugular bulb was involved in 7 cases. Modified transcochlear approaches or infratemporal fossa approaches were used in all cases. There were no recurrences.

CONCLUSIONS

Classification is fundamental to choosing the right surgical approach. Transotic and modified transcochlear approaches hold the key to treating complex cases. Infratemporal fossa approach type B has to be used for extension into the clivus, sphenoid sinus, or rhinopharynx. Internal carotid artery, jugular bulb, and sigmoid sinus involvement should be identified before operation.

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.

Petroclival meningiomas: multimodality treatment and outcomes at long-term follow-up

OBJECTIVE

To evaluate patients' clinical outcome, survival, and performance status, at the long-term follow-up evaluation after aggressive microsurgical resection of petroclival meningiomas.

METHODS

During a 13-year period (1991-2004), 150 patients underwent 207 operative procedures for resection of petroclival meningiomas. The tumor size was large in 79% of the patients, with a mean tumor diameter of 3.44 cm. Tumors extended into adjoining regions in 57% of the patients. Thirty patients (20%) previously underwent operation or irradiation. One hundred patients (66%) had a single operation, 43 patients (29%) had two operations, and seven patients (5%) had three operations. Gross tumor resection was accomplished in 48 patients (32%), subtotal resection in 65 patients (43%), and partial resection in 37 patients (25%). There were no operative deaths. Postoperative complications (cerebrospinal fluid leakage, quadriparesis, infections, cranial nerve palsies, etc.) were observed in 33 patients (22%). Postoperative radiation or radiosurgery was administered to 47 of the 102 patients who had residual tumors. The outcome and survival of patients were evaluated by questionnaires, telephone calls, and review of their recent radiological images.

RESULTS

At the conclusion of the study, 87 patients (58%) were alive with disease and 45 patients (30%) were alive without disease. The mean follow-up period was 102 months (range, 15-180 mo). Seven patients (5%; five of the subtotal and partially resected patients and two of the total resection patients) had recurrence; of these patients, two underwent repeat resection and four were treated with gamma knife radiosurgery. One of the patients died of tumor progression with no response to gamma knife radiosurgery. The recurrence-free survival rate was 100% at 3 years, 92.7% at 7 years, and 85% at 12 years; the progression-free survival rate was 96% at 3 years, 86.8% at 7 years, and 79.5% at 12 years. The Karnofsky Performance Scale score was 78 +/- 11 preoperatively, 76 +/- 11 at 1 year postoperatively, and 84 +/- 9 at the time of the latest follow-up evaluation. Common disabilities at the time of the follow-up evaluation included diplopia, loss of hearing, balance problems, and loss of sensation in the V1 and V2 cranial nerve distribution. Most patients developed coping mechanisms.

CONCLUSION

This series has the largest number of patients with the longest follow-up period, to our knowledge, reported in the literature to date. The excellent quality of life at the time of the long-term follow-up examination for these patients warrants aggressive but judicious tumor resection, with or without radiosurgical treatment of tumor remnants.

Effects of using combined transpetrosal surgical approaches to treat petroclival meningiomas

OBJECTIVE

Surgical treatment may be required for large petroclival meningiomas; however, surgery for these lesions is a major undertaking, and modern surgical approaches are still associated with considerable morbidity and recurrence rates. We analyzed our series of transpetrosally operated petroclival meningiomas to obtain detailed information regarding the surgery outcomes with respect to facial nerve effects, hearing changes, general neurological and psychosocial differences, and recurrence rates to identify opportunities for improvement.

METHODS

Between 1994 and 2004, we used transpetrosal approaches to operate on 29 patients for petroclival meningiomas larger than 30 mm. All patients were analyzed in detail regarding neurological outcomes and hearing abilities after surgery. Swedish-speaking patients were contacted for a psychosocial follow-up evaluation using the short-item 36 (SF-36) form.

RESULTS

After surgery, the Glasgow Outcome Score improved in 14 patients, was unchanged in 11 patients, and worsened in four patients. Facial nerve function was found to be of House-Brackmann Grade 3 or worse in six patients (including three individuals with transcochlear surgery and facial nerve rerouting). Of the 23 patients who underwent hearing-preservation surgery, serviceable hearing was preserved in 17 individuals. Nineteen Swedish patients were contacted for psychosocial evaluation. Three patients could not participate for health reasons; of the remaining 16 patients, 12 reported physical health scores that were below mean values for the general population. For patients who did not experience very serious neurological compromise, we found that unexpected painful trigeminal neuropathy and unilateral swallowing difficulties conveyed a negative influence on health. Three years after surgery, the patients reported more normalized health scores.

CONCLUSION

Generally, outcomes compared well with current reports. Outcomes can be improved, however by improving patients' psychosocial support; striving to decompress, preserve, and minimize dissection of ill-defined planes of cranial nerves; and using Simpson Grade 4 gamma knife approaches when radicality is precluded. Currently, the performance of transpetrosal surgery for petroclival meningiomas is a major undertaking that significantly affects a patient's health for several years; however, the approaches that we used allowed a high degree of tumor control with relatively little neurological morbidity.

Petrous bone cholesteatoma: clinical longitudinal study

The object of this retrospective study was to describe a series of patients with petrous bone cholesteatomas, paying particular attention to classification, diagnosis, surgical strategy, results, complications and recurrences. Furthermore, the study was designed to evaluate the impact of imaging techniques on an early diagnosis. Topographically, the petrous bone cholesteatomas of the present series were grouped using Sanna's classification and different surgical approaches were used. High resolution CT and/or MRI were used to follow-up the patients. The case notes of 52 patients with petrous bone cholesteatomas who were referred to our hospital for surgery between 1987 and 2003 were reviewed postoperatively. There were 45 primary cases and 7 recurrences. The facial nerve had been infiltrated and compressed by the cholesteatoma in 18 patients. Fourteen were managed with cable grafts using sural nerve or great auricular nerves. About 26 patients with preoperative grade I confirmed their normal facial function in 23 cases. In the other ten patients, the preoperative facial paralysis was due to compression by the cholesteatoma and its removal provided partial recovery of facial function in four patients. Our study compared two observation periods (1987-1996 and 1997-2003) when the diffusion and the availability of imaging techniques in our national health system had considerably increased. Two important factors emerged: firstly, the number of less extensive surgical approaches was higher in the more recent observation period, proving that cholesteatomas smaller in size had been diagnosed. Secondly, preoperative facial paralysis was less frequent in the same period-falling to 25% of cases of total facial paralysis from the 45.8% of the earlier period-practically half as much. The partial paralyses instead increased slightly, demonstrating that otologists have become more sensitive to and pay more attention to this symptom.

Petrous bone cholesteatoma: management and outcomes

OBJECTIVE

Cholesteatoma of the petrous bone is a rare pathology that grows slowly and is often asymptomatic. High clinical suspect is recommended for its diagnosis. With the advancement of imaging, clinical diagnosis is confirmed and follow up is assured. The present study is presented to state our experience in management of petrous bone cholesteatoma (PBC) and an overview of the outcome results.

METHODS

This study was a retrospective case review conducted at a private quaternary referral center. From January 1984 to October 2004, 93 of 2,739 patients with chronic otitis media with cholesteatoma were treated surgically for PBC with varying location types.

RESULTS

The mean age in this study was 46 years. Ninety-four percent of patients presented with hearing loss. Facial paralysis constituted 55% of the presented manifestations and grade VI palsy was the most common. A massive type of PBC was found to affect 45% of patients and it was mainly the acquired pathology. The surgical approaches varied according to the class type of PBC. Postoperative complications were minimal, and follow up was carried out after 1 year from the surgery date.

CONCLUSION

Petrous bone cholesteatoma presents difficulties in its diagnosis and treatment. Adequate history-taking, high clinical suspicious, with the advancement of imaging techniques made its diagnosis more feasible. Improvement of the lateral skull base approaches rendered possible safe, adequate, and complete removal of the pathology.

Guidelines for the ligation of the sigmoid or transverse sinus during large petroclival meningioma surgery

The authors present guidelines for the ligation of the transverse or sigmoid sinus during the surgical removal of petroclival meningiomas. The medical records and venograms of 14 patients with a petroclival meningioma requiring transverse or sigmoid sinus ligation treated in the Department of Neurosurgery, Seoul National University Hospital between 1986 and 1999 were reviewed. All patients successfully received a sinus trial clamping during the operation. The drainage pattern of the confluens of Herophili was classified into four types: Type A, confluens and equal on both transverse sinuses; Type B, confluens and nondominant transverse sinus on the tumor side; Type C, confluens and dominant transverse sinus on the tumor side; and Type D, unilateral transverse sinus only. Of the 14 cases, four were Type A, five were Type B, and two were Type C. There was no brain swelling after intraoperative test clamping of the sinus for more than 30 minutes. None of the cases developed postoperative complications related to the sinus ligation. Patients with Type A, B, or C drainage patterns were ideal candidates for sinus ligation, especially transverse sinus ligation, if the test clamping proved to be safe. The sinus was cut proximal to the superior petrosal sinus, distal to the vein of Labbé.

Transcavernous approach to diseases of the anterior upper third of the posterior fossa

Object

The region in the upper anterior third of the posterior fossa is a surgically hidden, narrow corridor between the petroclival surface anteriorly and the surface of the brainstem posteriorly. Although several approaches have been described to help surgeons reach this region, few of them enable practitioners to reach the different corners of the area and provide as wide a view as the one achieved using the transcavernous route.

Methods

A transcavernous approach was used in 91 cases (50 complex upper basilar artery [BA] aneurysms, 30 upper petroclival junction meningiomas, five trigeminal nerve schwannomas, three upper clival chordomas, and three anterior pontine lesions) involving the anterior upper third of the posterior fossa. The approach uses the pretemporal route with exposure of the lateral wall of the cavernous sinus. It entails removal of the anterior clinoid process. The posterior clinoid process is also removed when necessary. The approach leads to the upper basilar region. It is widened inferiorly to expose the anterior aspect by removal of the posterior clinoid process and the petroclival osseous and dural elements. Its lateral extension exposes the region of the Meckel cave and it can be widened by removal of the petrous apex.

Seventy patients experienced new transient mild cranial neuropathies, 67 of whom recovered fully. Surgically related ischemic morbidities occurred in three patients with BA aneurysms (one small medial thalamic infarct, ataxia due to superior cerebellar artery ischemia, and distal middle cerebral artery embolus in a patient with atrial fibrillation in whom anticoagulation therapy was stopped). All the neuropathies in patients with BA aneurysms were oculomotor and recovery was the rule in all of them. Three new permanent cranial neuropathies occurred in the patients with meningiomas. In seven patients with preoperative neuropathy, two had partial improvement. Five patients with atypical meningiomas were treated with postoperative radiation therapy. Progression occurred later in four patients who were treated with gamma knife surgery. There were no surgery-related deaths. More than 1 year of follow-up data were available in 85 patients, and 94% of those patients were in an active and functional state (Glasgow Outcome Scale scores of 4 and 5).

Conclusions

The safety achieved with the transcavernous route allows surgeons to achieve wide exposures to lesions involving the anterior upper third of the posterior fossa. It is an approach that should be mastered by every neurosurgeon dealing with cranial lesions.

Facial Nerve Rerouting in Skull Base Surgery

Facial nerve rerouting techniques were developed to facilitate re-section of extensive tumors occupying the skull base. Facial nerve rerouting has its own limitations and risks, requiring microsurgical expertise, additional surgical time, and often some degree of facial nerve paresis. This article presents different degrees of anterior and posterior facial nerve rerouting, techniques of facial nerve rerouting, and a comprehensive review of outcomes. It then reviews anatomic and functional preservation of the facial nerve in acoustic neuroma resection, technical aspects of facial nerve dissection, intracranial facial nerve repair options, and outcomes for successful acoustic neuroma surgery.

Management of the internal carotid artery in tumors of the lateral skull base: preoperative permanent balloon occlusion without reconstruction

OBJECTIVE

To present our experience with permanent preoperative balloon occlusion of the internal carotid artery while dealing with different abnormalities of the lateral skull base and a comparison with the results mentioned in the literature.

STUDY DESIGN

Retrospective case review.

SETTING

Private neurotologic and skull base tertiary referral center.

PATIENTS

Fifteen patients who underwent preoperative balloon occlusion of the internal carotid artery and surgery subsequently for various abnormalities of the lateral skull base between 1989 and 2002.

INTERVENTIONS

Each patient was subjected to four-vessel angiography along with the manual cross-compression test and balloon test occlusion to assess the efficacy of the collateral circulation. After angiography, each patient underwent a preoperative balloon occlusion, after which a lateral skull base procedure was performed for removal of the abnormality.

MAIN OUTCOME MEASURES

Only those patients showing evidence of adequate collateral cerebral circulation and a less than 1-second delay between the angiographic phases of the two cerebral hemispheres on angiography were considered fit for preoperative balloon occlusion. While under going the preoperative balloon occlusion, the patients were clinically assessed for the development of any neurologic symptoms and signs. Long-term follow-up after surgery was also based on the development of symptoms and signs of neurovascular compromise.

RESULTS

A major complication in the form of long-lasting hemiplegia occurred in one patient (6.7%). This complication was the result of technical factors rather than an effect of cerebral ischemia, because it was caused by an intimal dissection produced by the catheter. A defect in the visual field occurred in one patient (6.7%) that resolved partially after antiplatelet therapy. There was no mortality in our series related to preoperative balloon occlusion of the internal carotid artery.

CONCLUSION

Preoperative balloon occlusion of the internal carotid artery can still be considered a viable option for the management of the internal carotid artery during lateral skull base surgery. Proper preoperative evaluation of the adequacy and efficacy of the collateral cerebral circulation reduces the chances of postoperative neurovascular complications.

Management of jugular paragangliomas: the Gruppo Otologico experience

OBJECTIVE

The objective of this study was to review the outcome of surgical management in patients of jugular paragangliomas.

STUDY DESIGN

We conducted a retrospective case review.

SETTING

Tertiary care otology and skull base center.

MATERIALS AND METHODS

Fifty-five patients with the diagnosis of a jugular paraganglioma (Fisch Class C and D Glomus Jugulare) were managed over a period of 15 years. All patients with adequate follow up and complete records (53 cases) were reviewed with emphasis on the results of surgical management and the factors influencing them.

INTERVENTION

All 53 patients were managed with a view to surgically extirpate the tumor. The primary approach was the infratemporal fossa approach-Type A used in the majority of the patients. In eight cases, the procedure was staged owing to the presence of large intracranial extension. Three patients required additional procedures to ameliorate the after-effects of lower cranial nerve resection.

RESULTS

Gross total tumor removal was achieved in 49 patients. There were five cases of recurrence. Coupled with the residual tumors in five patients, the surgical control achieved was 83%. There was no perioperative mortality. There were two cases of postoperative cerebrospinal fluid leak, both of which required surgical exploration and closure. The facial nerve was resected in seven patients. The overall preservation rate of clinically uninvolved lower cranial nerves was 75%.

CONCLUSIONS

The low level of complications along with a high surgical control achieved makes surgery the primary mode of treatment in the vast majority of these tumors, regardless of the size and location.

Transapical extension in difficult cerebellopontine angle tumors

The transapical extension of the enlarged translabyrinthine approach is aimed at making the removal of certain tumors of the cerebellopontine angle simpler and with less morbidity. The extension is classified into 2 types--type I and type II--based on the extent of bone drilling around the internal auditory canal. Type I extension involves drilling for 300 degrees to 320 degrees around the canal and is indicated for large or giant vestibular schwannomas and vestibular schwannomas with significant extension anterior to the internal auditory canal. Type II extension entails complete removal of the bone around the canal for 360 degrees and is indicated for meningiomas of the posterior surface of the petrous bone extending anterior to the internal auditory canal. The extension allows better control over the anterior pole of the tumor, the displaced facial nerve, the prepontine cistern, and the venous vascularity of the cerebellopontine angle. The aim of this report is to present our experience with this extension.

Enlarged translabyrinthine approach for the management of large and giant acoustic neuromas: a report of 175 consecutive cases

The translabyrinthine approach was once considered inadequate for the removal of acoustic neuromas (ANs), but that theory has few proponents today. Over the years, the translabyrinthine approach has been modified into the enlarged translabyrinthine approach, with experience and technical refinements leading to a wider access. Between April 1987 and December 2001, the Gruppo Otologico of Piacenza-Rome was able to remove 175 ANs 3 cm or larger in size from the cerebellopontine angle by adopting this modified surgical technique. These tumors represented 24.7% of all 707 ANs for which surgery was performed during the same period of time. Among the 175 cases, there was only 1 death. The incidence of complications was very low and was comparable to results previously published in the literature. Consequently, the hospital stay was short, with a mean of 7.3 days (5.1 days in the last 45 cases). The preoperative ipsilateral hearing was already compromised in 119 of the 175 cases (68%; class C/D according to the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery, 1995). From our results, we can conclude that the use of the enlarged translabyrinthine approach in AN surgery is not dependent on tumor size. On the contrary, the advantages of a low rate of morbidity and a short hospital stay are ample proof that this is the best approach for the removal of large ANs.

Transbasal approaches: surgical details, pitfalls and avoidances

Lesions involving the anterior skull base and sphenoclival region are difficult surgical problems. This paper presents surgical details, pitfalls, avoidances and our experiences in the surgical treatment of lesions of the anterior skull base using neuronavigation. Between 1999 and 2003, 33 patients with pathology of the anterior skull base were operated on via the traditional transbasal and the extended transbasal approach. A passive-marker-based neuronavigation system has been used for intraoperative image guidance since April 2000. The patients consisted of 11 men and 22 women. Their ages ranged from 3 to 76 years, with a mean of 41 years. The lesions for which the approach was used included 9 cerebrospinal fluid (CSF) fistulae and 24 neoplastic lesions including meningioma (16 cases), metastasis (3 cases), chordoma (3 cases), plasmacytoma (1 case), and osteoma (1 case). Gross total removal of the tumors was accomplished in 22 out of 24 patients with tumor (91.6%). Postoperative complications include CSF leakage (2 cases), infection (2 cases) and transient impaired vision (1 case). One patient (3%) died postoperatively from hypothalamic dysfunction after removal of a benign tumor extending to the anterior third ventricle. Despite the incidence of postoperative infection and the high rate of CSF leakage and death, it is possible to obtain long-term survival for patients with tumors previously considered challenging and difficult surgical problems.

Anterior and Posterior Facial Nerve Rerouting: A Comparative Study

The infratemporal fossa type A (IFT-A) and the modified transcochlear approach are used to remove glomus jugular tumors type C and petroclival tumors extending to the prepontine cistern, respectively. Anterior rerouting is a key step in IFT-A, whereas the modified transcochlear approach involves posterior rerouting. The aim of this study was to analyze facial nerve function after application of the two procedures. One year after surgery, anterior rerouting was associated with excellent to good outcomes (grade I to III) in 94 % of the cases, while posterior rerouting was associated with good outcomes (grade III) in 70 % of the cases.

Advanced image-guided skull base surgery

BACKGROUND

Tumors of the skull base frequently encase or extend into normal neural and vascular structures. Preoperative planning and intraoperative identification of anatomic landmarks is especially important in complex tumors since it helps avoid or minimize surgical morbidity.

METHODS

By creating a surgical plan the image guidance software offers help in the establishment of a surgical approach. During surgery, the neuronavigation system displays the location of anatomic landmarks of the skull base regardless of any erosion or displacement.

RESULTS

A series of 10 patients with complex tumors in various skull base locations is reported. Osseous structures are easily identified using the CT-based image guidance since these landmarks do not shift due to CSF loss. Image fusion of CT and MRI data gives additional information on the displacement of soft tissue structures. Image fusion in a substraction mode is helpful when a tumor has invaded bony structures or when the encasement of major vessels has to be visualized.

CONCLUSION

The preoperative data preparation (planning of the approach, image fusion) plays a vital role in modern neuronavigation and contributes useful information during surgery for complex skull base tumors. Such advanced neuronavigation increases the efficacy and safety of intraoperative maneuvers. Eroded and distorted anatomic landmarks are not subject to a significant amount of intraoperative shift throughout the surgical procedure.

Long-term outcome and growth rate of subtotally resected petroclival meningiomas: experience with 38 cases

OBJECTIVE

To evaluate the long-term outcome of a subtotally resected residual tumor and to assess its growth rate, we analyzed the records of 38 patients with residual petroclival meningioma.

METHODS

Clinical records and radiological findings of 38 cases of petroclival meningioma that were diagnosed and subtotally resected at Seoul National University Hospital between 1981 and 1997 were carefully reviewed. Follow-up imaging studies were reviewed, and Karnofsky performance scale scores at the last follow-up were recorded. The duration of follow-up ranged from 6 to 141 months (mean, 47.5 mo; median, 30 mo). Tumor progression and progression-free survival rates were assessed. The growth rate of a residual tumor was evaluated by measuring the equivalent diameter and the tumor volume serially; the tumor doubling time was calculated, and the predictive factors for determining the growth pattern in residual tumors and the prognosis were analyzed.

RESULTS

In 33 (87%) of the 38 patients, Karnofsky performance scale scores at the last follow-up were 80 or above. The median progression-free survival time among patients with subtotally resected tumors was 66 months, and the 5-year progression-free survival rate was 60%. The growth rate of residual tumors was low (volume increase, 4.94 cc/yr; diameter increase, 0.37 cm/yr). The mean tumor doubling time was 8 years. Although there were no significant predictive factors, age and extent of tumor resection seemed to influence the progression-free survival rate. Significant factors affecting the growth rate were age and occurrence of menopause.

CONCLUSION

Subtotal resection with or without radiation or radiosurgery should be considered as a suitable treatment option for patients with petroclival meningiomas, especially the elderly, because the growth rate of residual tumors is low.

Retrosigmoid intradural suprameatal approach to Meckel's cave and the middle fossa: surgical technique and outcome

OBJECT

The goal of this study was to determine whether some petroclival tumors can be safely and efficiently treated using a modified retrosigmoid petrosal approach that is called the retrosigmoid intradural suprameatal approach (RISA).

METHODS

The RISA was introduced in 1983, and since that time 12 patients harboring petroclival meningiomas have been treated using this technique. The RISA includes a retrosigmoid craniotomy and drilling of the suprameatus petrous bone, which is located above and anterior to the internal auditory meatus, thus providing access to Meckel's cave and the middle fossa. Radical tumor resection (Simpson Grade I or II) was achieved in nine (75%) of the 12 patients. Two patients underwent subtotal resection (Simpson Grade III). and one patient underwent complete resection of tumor at the posterior fossa with subtotal resection at the middle fossa. There were no deaths or severe complications in this series; all patients did well postoperatively, being independent at the time of their last follow-up examinations (mean 5.6 years). Neurological deficits included facial paresis in one patient and worsening of hearing in two patients.

CONCLUSIONS

The approach described here is a useful modification of the retrosigmoid approach, which allows resection of large petroclival tumors without the need for supratentorial craniotomies. Although technically meticulous, this approach is not time-consuming; it is safe and can produce good results. This is the first report on the use of this approach for petroclival meningiomas.

Retrosigmoid intradural suprameatal approach to Meckel's cave and the middle fossa: surgical technique and outcome

Object

The goal of this study was to determine whether some petroclival tumors can be safely and efficiently treated using a modified retrosigmoid petrosal approach that is called the retrosigmoid intradural suprameatal approach (RISA).

Methods

The RISA was introduced in 1983, and since that time 12 patients harboring petroclival meningiomas have been treated using this technique. The RISA includes a retrosigmoid craniotomy and drilling of the suprameatus petrous bone, which is located above and anterior to the internal auditory meatus, thus providing access to Meckel's cave and the middle fossa.

Radical tumor resection (Simpson Grade I or II) was achieved in nine (75%) of the 12 patients. Two patients underwent subtotal resection (Simpson Grade III), and one patient underwent complete resection of tumor at the posterior fossa with subtotal resection at the middle fossa. There were no deaths or severe complications in this series; all patients did well postoperatively, being independent at the time of their last follow-up examinations (mean 5.6 years). Neurological deficits included facial paresis in one patient and worsening of hearing in two patients.

Conclusions

The approach described here is a useful modification of the retrosigmoid approach, which allows resection of large petroclival tumors without the need for supratentorial craniotomies. Although technically meticulous, this approach is not time consuming; it is safe and can produce good results. This is the first report on the use of this approach for petroclival meningiomas.

The supracondylar approach to the jugular tubercle and hypoglossal canal

BACKGROUND

Circumscribed lesions of the hypoglossal canal and of the jugular tubercle still remain a surgical challenge. So far, transpetrosal, transcondylar suboccipital, and extreme lateral approaches have been used to access this region. These surgical procedures bear a high risk for neurological deficits. Therefore, we introduce a new minimally invasive extradural approach to the hypoglossal canal that also allows access to the lateral aspects of the jugular tubercle.

METHODS

After a paramedian retromastoid skin incision, a basal suboccipital craniectomy lateral to the foramen magnum toward the jugular tubercle is performed. With this approach the occipital condyle and the lateral osseous circumference of the foramen magnum are preserved. Drilling extradurally, the dorsal parts of the jugular tubercle are removed. The exposure is extended downward to the posterior margins of the hypoglossal canal and laterally to the jugular bulb, enabling a minimally invasive exposure of the hypoglossal canal, the lateral aspects of the jugular tubercle, and medial aspects of the jugular bulb.

RESULTS

Using this supracondylar approach, surgical interventions were performed in three patients suffering from a hypoglossal neurinoma, a cholesterol granuloma extending into the jugular tubercle, and a cyst of the hypoglossal canal, respectively. No additional postoperative neurological deficits were seen.

CONCLUSIONS

The supracondylar approach seems to be useful to gain access to benign lesions of the hypoglossal canal and of the jugular tubercle to decompress tumors or cysts. In contrast to previously reported techniques this approach has a low risk of morbidity. The surgical field, however, is restricted laterally by the jugular bulb, medially and basally by the residual occipital condyle and dorsally by the dura. Therefore, this approach is useful to remove small lesions or to perform extended biopsies. Radical removal of large tumors seems to be problematic using this approach.

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.

Cerebrospinal Fluid Leak after Translabyrinthine Acoustic Neuroma Surgery

Cerebrospinal fluid leakage is the most common complication of translabyrinthine acoustic neuroma surgery. This retrospective study reviews patients who had translabyrinthine acoustic neuroma surgery at the Gruppo Otologico, Piacenza, Italy, and ENT Department of Bergamo General Hospital, Bergamo, Italy, during the last 6 years. The incidence of postoperative cerebrospinal fluid leakage was 6.2%, and 75% of these patients underwent another surgery to control the cerebrospinal fluid leakage. A modification of translabyrinthine approach was used in patients with highly pneumatized temporal bones to prevent cerebrospinal fluid leakage in these high-risk patients.