Neurosurgery Blog

J Neurosurg 117:654–665, 2012

Surgery for giant anterior clinoidal meningiomas that invade vital neurovascular structures surrounding the anterior clinoid process is challenging. The authors present their skull base technique for the treatment of giant anterior clinoidal meningiomas, defined here as globular tumors with a maximum diameter of 5 cm or larger, centered around the anterior clinoid process, which is usually hyperostotic.

Methods. Between 2000 and 2010, the authors performed 23 surgeries in 22 patients with giant anterior clinoidal meningiomas. They used a skull base approach with extradural unroofing of the optic canal, extradural clinoidectomy (Dolenc technique), transdural debulking of the tumor, early optic nerve decompression, and early identification and control of key neurovascular structures.

Results. The mean age at surgery was 53.8 years. The mean tumor diameter was 59.2 mm (range 50–85 mm) with cavernous sinus involvement in 59.1% (13 of 22 patients). The tumor involved the prechiasmatic segment of the optic nerve in all patients, invaded the optic canal in 77.3% (17 of 22 patients), and caused visual impairment in 86.4% (19 of 22 patients). Total resection (Simpson Grade I or II) was achieved in 30.4% of surgeries (7 of 23); subtotal and partial resections were each achieved in 34.8% of surgeries (8 of 23). The main factor precluding total removal was cavernous sinus involvement. There were no deaths. The mean Glasgow Outcome Scale score was 4.8 (median 5) at a mean of 56 months of follow-up. Vision improved in 66.7% (12 of 18 patients) with consecutive neuroophthalmological examinations, was stable in 22.2% (4 of 18), and deteriorated in 11.1% (2 of 18). New deficits in cranial nerve III or IV remained after 8.7% of surgeries (2 of 23).

Conclusions. This modified surgical protocol has provided both a good extent of resection and a good neurological and visual outcome in patients with giant anterior clinoidal meningiomas.

Neurosurgery 71[ONS Suppl 1]:ons146–ons159, 2012

The jugular tubercle is a rounded bony prominence that arises from the inferolateral margin of the clivus. In a previous publication, we described the surgical anatomy of the expanded endonasal approach to the jugular tubercle.

OBJECTIVE: To illustrate the translation of laboratory work to the operating room describing the anatomic and technical nuances of the endonasal approach to the jugular tubercle.

METHODS: We review the relevant surgical anatomy needed to perform an endonasal approach to the jugular tubercle, and we select 4 different lesions to illustrate the application of our laboratory findings.

RESULTS: In the first case, exposure and partial drilling of the jugular tubercle was critical to gain an adequate corridor to the meningioma, particularly to its inferolateral margin. This allowed for early devascularization, safe extracapsular dissection, and preservation of surrounding neurovascular structures. In addition, the jugular tubercle was hyperostotic and its resection, along with generous dural removal, provided a grade I Simpson tumor resection. In the second (chondrosarcoma) and third (chordoma) cases, the jugular tubercle was infiltrated by tumor, and consequently its complete resection was essential to achieve total tumor removal. In the last case, an unusual adrenocorticotropic hormone-secreting adenoma recurrence at the jugular tubercle region, the technical modification of the transclival approach presented here was successfully applied to achieve complete resection and Cushing disease remission.

CONCLUSION: The transjugular tubercle variant of the expanded endonasal transclival approach allows for direct access to ventrolateral lesions in the inferior clival/petroclival region with no cerebral or cerebellar retraction, or cranial nerve manipulation during the approach.

Neurosurg Focus 33 (2):E10, 2012

Although they provide excellent ventral and lateral exposure of the brainstem, petrosal approaches to brainstem cavernous malformations (CMs) are infrequently reported.

Methods. The authors reviewed their experience with petrosal approaches to brainstem CMs in combination with a comprehensive review of the literature to elucidate resection rates, complication rates, and outcomes.

Results. Including their own results, the authors found 65 cases in 20 reports of brainstem CMs treated with petrosal approaches. The specific approaches were posterior petrosal in 37 cases (57%), anterior petrosal in 17 (26%), extended posterior petrosal in 10 (15%), and a combined petrosal approach in 1 case (2%). For 50 cases in 16 reports with detailed outcome information, the overall complete resection rate was 90%, with early postoperative morbidity reported in 30% of cases and permanent morbidity in 14%. The rate of CSF leakage was 6%.

Conclusions. The versatile petrosal approaches to brainstem CMs are associated with good outcomes and an acceptable morbidity rate. More expansive lesions can be approached using a combination of the standard anterior and posterior petrosal approach, preserving hearing and avoiding the greater complication rates associated with extended posterior petrosal approaches.

Neurosurgery 70[ONS Suppl 2]:ons202–ons208, 2012 DOI: 10.1227/NEU.0b013e31824042e6

Approaches to the foramen magnum and upper cervical spine traditionally include the posterior midline, far lateral, and endoscopic endonasal approaches. The far lateral approach is a well-established technique for the removal of pathology ventrolateral to the brainstem and the craniocervical junction, but it may be too extensive for lesions limited to areas far from the midline.

OBJECTIVE: To present an alternative to the commonly used approaches to the foramen magnum and upper cervical.

METHODS: We used an approach directly overlying ventral or lateral pathology.

RESULTS: Two cases are presented in which the direct lateral approach followed by an occipitocervical fusion was successfully performed.

CONCLUSION: This approach can be considered for patients in whom a ventral decompression is necessary but an endoscopic endonasal approach is undesirable or when a ventral, lateral, and ventrolateral resection of tumor, pannus, or infection is required.

Neurosurg Rev (2012) 35:185–194. DOI 10.1007/s10143-011-0346-1

Jugular foramen paragangliomas are rare skull base tumours posing multiple complex diagnostic and management problems. We did a study to evaluate surgical technique, outcome and complications in 75 cases of tumours treated by multidisciplinary approach (i.e. combined neurosurgery, neuroradiology, ear, nose and throat surgery and intensive care unit team).
Methods: Retrospective study on 75 consecutive patients with jugular foramen paragangliomas treated surgically from 1989 to 2005. Preoperative balloon occlusion test was performed in all patients as well as embolization (100%). A combined limited infratemporal and juxtacondylar approach was used in all patients.
Results: Gross total resection was achieved in 59 patients (78.7%). The most common complication was represented by lower cranial nerve deficits in five patients (6.6%), which was only temporary in three. Postoperative facial nerve weakness occurred in five cases (6.6%) and resolved in three of them. The remaining two patients underwent facial nerve reconstruction by hypoglossal/facial nerve anastomosis. Four patients (5.3%) had a postoperative cerebrospinal fluid leak, which was successfully treated by lumbar drainage. Two patients (2.7%) died because of complications related to surgical injury of lower cranial nerves: one patient developed aspiration pneumonia and septicemia and the second one developed a large cervicobulbar hematoma that led to severe respiratory distress and ultimately global cerebral hypoxia.
Conclusion: Paragangliomas are rare and complex skull base lesions that may be managed with low morbidity and mortality if a multidisciplinary approach is considered. Facial and lower cranial nerve postoperative deficits can be limited.

J Neurosurg 116:697–702, 2012. http://thejns.org/doi/abs/10.3171/2011.12.JNS111404

Facial nerve paresis can be a devastating complication following resection of large (> 2.5 cm) cerebellopontine angle (CPA) tumors. The authors have developed and used a new high-density diffusion tensor imaging (HD-DT imaging) method, aimed at preoperatively identifying the location and course of the facial nerve in relation to large CPA tumors. Their study objective was to preoperatively identify the facial nerve in patients with large CPA tumors and compare their HD-DT imaging method with a traditional standard DT imaging method and correlate with intraoperative findings.

Methods. The authors prospectively studied 5 patients with large (> 2.5 cm) CPA tumors. All patients underwent preoperative traditional standard- and HD-DT imaging. Imaging results were correlated with intraoperative findings.

Results. Utilizing their HD-DT imaging method, the authors positively identified the location and course of the facial nerve in all patients. In contrast, using a standard DT imaging method, the authors were unable to identify the facial nerve in 4 of the 5 patients.

Conclusions. The HD-DT imaging method that the authors describe and use has proven to be a powerful, accurate, and rapid method for preoperatively identifying the facial nerve in relation to large CPA tumors. Routine integration of HD-DT imaging in preoperative planning for CPA tumor resection could lead to improved facial nerve preservation.

J Neurosurg 116:773–791, 2012. http://thejns.org/doi/abs/10.3171/2011.12.JNS11791

The exploration of lesions in the mediobasal temporal region (MTR) has challenged generations of neurosurgeons to achieve an appropriate approach. To address this challenge, the extensive use of the paramedian supracerebellar-transtentorial (PST) approach to expose the entire length of the MTR, as well as the fusiform gyrus, was investigated.

Methods. The authors studied the microsurgical aspects of the PST approach in 20 cadaver brains and 5 cadaver heads under the operating microscope. They evaluated the features, advantages, difficulties, and limitations of the PST approach and refined the surgical technique. They then used the PST approach in 15 patients with large intrinsic MTR tumors (6 patients), tumor in the posterior fusiform gyrus with mediobasal temporal epilepsy (MTE) (1 patient), cavernous malformations in the posterior MTR including the fusiform gyrus (2 patients), or intractable MTE with hippocampal sclerosis (6 patients) from December 2007 to May 2010. Patients ranged in age from 11 to 63 years (mean 35.2 years), and in 9 patients (60%) the lesion was located on the left side.

Results. In all patients with neuroepithelial tumors or cavernous malformations, the lesions were completely and safely resected. In all patients with intractable MTE with hippocampal sclerosis, the anterior two-thirds of the parahippocampal gyrus and hippocampus, as well as the amygdala, were removed selectively through the PST approach. There was no surgical morbidity or mortality in this series. Three patients (20%) with high-grade neuroepithelial tumors underwent postoperative radiotherapy and chemotherapy but needed a second surgery for recurrence during the follow-up period. In all patients with MTE, antiepileptic medication could be decreased to a single drug at lower doses, and no seizure activity has occurred until this point.

Conclusions. The PST approach provides the surgeon precise anatomical orientation when exposing the entire length of the MTR, as well as the fusiform gyrus, for removing any lesion. This is a novel technique especially for removing tumors involving the entire MTR in a single session without damaging neighboring neural or vascular structures. This approach can also be a viable alternative for selective removal of the parahippocampal gyrus, hippocampus, and amygdala in patients with MTE due to hippocampal sclerosis.

J Neurosurg 116:291–300, 2012. DOI: 10.3171/2011.8.JNS101896

Smaller operative exposures, endoscopic approaches, and minimally invasive neurosurgery have emerged as a dominant trend in the modern era. In keeping with this evolution, the authors have recently eliminated the use of fixed retractors, instead employing dynamic retraction, with the use of handheld instruments. In the present study, the authors report the results of applying this strategy to challenging vascular and skull base lesions.

Methods. This 6-month study prospectively analyzed the use of retractorless surgery in a consecutive series of 223 patients with intracranial vascular or skull base lesions undergoing craniotomy. A single surgeon performed all operations.

Results. The microsurgical approaches (in descending order of frequency) included an orbitozygomatic craniotomy (77 patients [35%]), frontal (36 patients [16%]), retrosigmoid (27 patients [12%]), interhemispheric (16 patients [7%]), and lateral supracerebellar (15 patients [7%]). The most common lesions were aneurysms (83 lesions overall [37%]), 18 of which required a bypass. Of 159 vascular lesions, there were also 46 cavernous malformations (29%). Meningiomas were the most common skull base tumors (37 cases [58%]). Of the 223 patients, 7 cases of various vascular and skull base lesions required fixed retraction. Therefore, 97% of the cases were successfully treated without a self-retaining retractor system.

Conclusions. Fixed retraction can be supplanted by dynamic retraction with surgical instruments, limiting the risk of retractor-induced tissue edema and injury. This quiet revolution has precipitated a major change in surgical techniques. Extensive dissection of arachnoidal planes, careful placement of the handheld suction device, patient positioning that enhances gravity retraction, the refinement of microsurgical instrumentation, and appropriate selection of the operative corridor all serve to obviate the need for fixed retraction in most intracranial procedures. Retractorless neurosurgery is an achievable goal, even when complex lesions of the vasculature and skull base are being treated.

J Neurosurg 116:390–398, 2012.DOI: 10.3171/2011.10.JNS11783

The cavernous sinus and surrounding regions—specifically the Meckel cave, posterior sector of the cavernous sinus itself, and the upper part of the petroclival region—are the location of a large variety of lesions that require individual consideration regarding treatment strategy. These regions may be reached for biopsy by a percutaneous needle inserted through the foramen ovale. The aim of this retrospective study was to evaluate the diagnostic accuracy of percutaneous biopsy in a consecutive series of 50 patients referred for surgery between 1991 and 2010.

Methods. Seven biopsies (14%) were unproductive and 43 (86%) were productive, among which 28 lesions subsequently underwent histopathological examination during a second (open) surgery. To evaluate the diagnostic accuracy of the procedure, results from surgery were compared with those from the biopsy.

Results. Sensitivity of the percutaneous biopsy was 0.83 (95% CI 0.52–0.98), specificity was 1 (95% CI 0.79–1), and k coefficient was 0.81.

Conclusions. Because of its valuable diagnostic accuracy, percutaneous biopsy of the cavernous sinus and surrounding regions should be performed in patients with parasellar masses when neuroimaging does not provide sufficient information of a histopathological nature. This procedure would enable patients to obtain the most appropriate therapy, such as resective surgery, corticosteroids, chemotherapy, radiotherapy, or radiosurgery.

Neurosurg Rev (2012) 35:53–66. DOI 10.1007/s10143-011-0333-6

Meningiomas of the posterior fossa represent a heterogeneous group of tumors regarding difficulty of resection and functional outcome.

The aim of this review was to focus on tumors located mainly on the posterior surface of the petrous bone and threatening hearing and facial functions.

An anatomical classification was used to evaluate surgical outcome depending on the relationship of the tumor to the internal auditory meatus. The authors performed a retrospective chart review of 53 consecutive patients operated on for a posterior petrous bone meningioma in a tertiary referral center and a literature review. Tumors were classified in four groups according to the modified Desgeorges and Sterkers classification: posterior petrous (P; 17 tumors), meatus and internal auditory canal (M; 12 tumors), petrous apex without invasion of the internal auditory canal (A; 9 tumors), and cerebellopontine angle with invasion of the internal auditory canal (AMP; 15 tumors).

The facial function was preserved in 100% of P and A tumors, 75% of group M tumors, and 53% of AMP tumors. Hearing preservation was attempted only in P, A, and M groups where rates of serviceable hearing preservation were 82%, 80%, and 66%, respectively. The cumulative rate of hearing preservation for AMP tumors was 45% in our literature review. The increased facial morbidity associated with AMP tumors compared with other groups was also confirmed by the review of the literature.

In conclusion, this study shows that among posterior petrous bone meningiomas, tumors invading the internal auditory canal present with increased postoperative functional morbidity in spite of a tailored approach regarding dural insertion.

J Neurosurg 115:802–810, 2011.DOI: 10.3171/2011.5.JNS101812

Various surgical approaches, such as uni- and bifrontal, frontolateral, and pterional approaches, havebeen advocated for tuberculum sellae meningiomas. The authors retrospectively reviewed the effectiveness of a bilateralsubfrontal approach for tuberculum sellae meningiomas with special attention to ophthalmological outcomesand complications.

Methods. Between 1993 and 2009, 34 patients underwent surgery for removal of tuberculum sellae meningiomasat Osaka City University. Tumor size ranged from 14 to 45 mm. Thirty-two of 34 patients presented with visualdisturbances before the surgery. The visual functions in all patients were assessed using a visual impairment score(VIS) before and after surgery. Postoperative visual examination was performed 2 weeks after surgery. Long-termfollow-up examinations were conducted 1 year after surgery.

Results. Radical resection (Simpson Grades I and II) was accomplished in 27 patients, and subtotal or partialresection (Simpson Grades III and IV) was achieved in 7. There was no deterioration in postoperative visual outcome.Twenty-nine (90.6%) of 32 patients showed improved VIS compared with preoperative VIS. The average VIS was38.1 preoperatively, 23.5 in the short-term postoperative period, and 21.8 in the long-term postoperative period. Inthe short-term postoperative period, the visual function in 6 patients normalized, and visual problems persisted in theremaining 26. Six (23%) of 26 patients showed further improvement in VIS during the long-term follow-up period,and no patient exhibited a worsened VIS during this time. One patient complained of hyposmia after surgery, butthere was no indication of related complications such as CSF leakage or frontal brain contusion.

Conclusions. The bilateral subfrontal approach was previously avoided because of the relatively high rate ofcomplications in earlier surgical series of tuberculum sellae meningiomas. However, after developments in microsurgicaltechniques in recent years, the bilateral subfrontal approach can now provide satisfactory visual outcomes withminimal postoperative complications. Careful preservation of the blood supply to optic apparatus and early unroofingof the optic canal using a bilateral subfrontal approach led to further improvement in long-term postoperative visual outcome.

Neurosurg Rev DOI 10.1007/s10143-011-0334-5

Previous studies of chordoma have focused on either surgery, radiotherapy, or particular tumor locations. This paper reviewed the outcomes of surgery and proton radiotherapy with various tumor locations.

Between 2001 and 2008, 40 patients with chordomas of the skull base and cervical spine had surgery at our hospital. Most patients received proton therapy. Their clinical course was reviewed. Age, sex, tumor location, timing of surgery, extent of resection, and chondroid appearance were evaluated in regard to the progression-free survival (PFS) and overall survival (OS). The primary surgery (PS) group was analyzed independently. The extensive resection rate was 42.5%. Permanent neurological morbidity was seen in 3.8%. Radiotherapy was performed in 75% and the mean dose was 68.9 cobalt gray equivalents. The median followup was 56.5 months. The 5-year PFS and OS rates were 70% and 83.4%, respectively. Metastasis was seen in 12.5%. The tumor location at the cranio-cervical junction (CCJ) was associated with a lower PFS (P=0.007). In the PS group, a younger age and the CCJ location were related to a lower PFS (P=0.008 and P<0.001, respectively). The CCJ location was also related to a lower OS (P=0.043) and it was more common in young patients (P=0.002). Among the survivors, the median of the last Karnofsky Performance Scale score was 80 with 25.7% of patients experiencing an increase and 11.4% experiencing a decrease.

Multimodal surgery and proton therapy thus improved the chordoma treatment. The CCJ location and a younger age are risks for disease progression.

Neurosurg Rev. DOI 10.1007/s10143-011-0340-7

The paper describes a retrospective study of a consecutive series of 20 midline anterior cranial fossa meningiomas (five of the olfactory groove, 14 of the tuberculum sellae, and one clinoidal), which were operated on via a supraorbital keyhole approach between 2002 and 2008.

The series includes three males and 17 females (mean age 57 years, mean size of the tumors 3.5×3 cm, and mean follow-up 48 months). Gross total excision was achieved in 18 cases and subtotal resection in two. Out of 14 patients with visual deficits, nine patients improved, one remained stable, and three deteriorated. Two patients presented a recurrence 3 years after surgery. One peri-operative death was recorded.

The subgroup of patients with tuberculum sellae meningiomas was analyzed in details. A meta-analysis of the major series of such meningiomas in the last 20 years has been performed in order to compare results of different surgical techniques. With regard to primary outcomes of these tumors, gross total removal, restoration of visual function, morbidity, mortality, and recurrence rates, the supraorbital approach, for selected cases, seems to offer valuable results, comparable with those reported in conventional and endoscopic approaches and with very low surgical aggressiveness. However, statistical data available from the literature, particularly on visual function, are still too limited to draw definitive conclusions.

The best surgical option for the individual patient cannot yet be standardized and should be chosen on the basis of tumor anatomy, pre-operative clinical symptoms, and surgeon’s experience.

Neurosurg Rev. DOI 10.1007/s10143-011-0329-2

Esthesioneuroblastoma is an uncommon malignant tumor originating in the upper nasal cavity. The surgical treatment for this tumor has traditionally been via an open craniofacial resection. Over the past decade, there has been tremendous development in endoscopic techniques.

In this report, we performed a retrospective analysis of patients with esthesioneuroblastomas treated with a purely endonasal endoscopic approach and resection at the Johns Hopkins Hospital between January 2005 and April 2010.

A total of eight patients with esthesioneuroblastoma, five men and three women, were identified. Six patients were treated for primary disease, and two were treated for tumor recurrence. The modified Kadish staging was A in one patient (12.5%), B in two patients (25%), C in four patients (50%), and D in one patient (12.5%). All patients had a complete resection with negative intraoperative margins. One patient had intraoperative hypertension; there were no perioperative complications. With a mean follow-up of over 27 months, all patients are without evidence of disease. In addition, we reviewed the literature and identified several overlapping case series of patients with esthesioneuroblastoma treated via a purely endoscopic technique.

Our series adds to the growing experience of expanded endonasal endoscopic surgery in the treatment of skull base tumors including esthesioneuroblastoma. Longer follow-up on a larger number of patients is required to further demonstrate the utility of endoscopic approaches in the management of this malignancy.

Neurosurg Rev (2011) 34:327–335. DOI 10.1007/s10143-011-0308-7

Aggressive tumor removal is not always the best treatment for petroclival meningioma (PCM). However, radical removal actually provides the cure with minimal morbidity.

We evaluated the relation of surgical results and tumor size in the PCM removal to clarify the treatment policy for PCM. This study comprised 32 consecutive patients with newly-diagnosed PCM who underwent tumor removal; tumor size was small (< 3 cm) in 12 patients and large (≥3 cm) in 20. Tumor removal was classified into radical (Simpson’s grade I/II) and non-radical (Simpson’s grade III/IV). Removal of small PCM was 11 radical and one non-radical; no surgical morbidity/mortality occurred and postoperative regular follow-up using magnetic resonance imaging showed no recurrence in the period of 66± 45 months. Removal of large PCM was eight radical and 12 non-radical; despite no mortality, the incidence of permanent cranial nerve deficits and major neurological deficits newly developed postoperatively was 35% and 25%, respectively. Radical removal was significantly more frequent in small PCMs than in large PCMs. Permanent cranial nerve deficits newly developed postoperatively and poor outcome (Karnofsky score ≤80) were significantly more frequent in large PCMs than in small PCMs. Radical removal of small PCM is achieved with minimal morbidity and results in the cure. Notwithstanding high morbidity, aggressive removal of large PCM does not achieve a high rate of radical removal.

To find and remove PCM radically while it is small is the only way to cure the disease with minimal morbidity.

J Neurosurg 114:1571–1577, 2011. DOI: 10.3171/2011.1.JNS091939

Stereotactic radiosurgery serves as an important primary and adjuvant treatment option for patients with many types of intracranial meningiomas. This is particularly true for patients with parasellar meningiomas. In this study, the authors evaluated the outcomes of Gamma Knife surgery (GKS) used to treat parasellar meningiomas.

Methods. The study is a retrospective review of the outcomes in 138 patients with meningiomas treated at the University of Virginia from 1989 to 2006; all patients had a minimum follow-up of 24 months. There were 31 men and 107 women whose mean age was 54 years (range 19–85 years). Eighty-four patients had previously undergone resection. The mean pre-GKS tumor volume was 7.5 ml (range 0.2–54.8 ml). Clinical and radiographic evaluations were performed, and factors related to favorable outcomes in each case were assessed.

Results. The mean follow-up duration was 84 months (median 75.5 months, range 24–216 months). In 118 patients (86%), the tumor volume was unchanged or had decreased at last follow-up. Kaplan-Meier analysis demonstrated radiographic progression-free survival at 5 and 10 years to be 95.4% and 69%, respectively. Fourteen patients (10%) developed new cranial nerve palsies following GKS. Factors associated with tumor control included younger age, a higher isodose, and smaller tumor volume. A longer follow-up duration was associated with either a decrease or increase in tumor volume. Fourteen patients (10%) experienced new or worsening cranial nerve deficits after treatment. Factors associated with this occurrence were larger pretreatment tumor volume, lower peripheral radiation dose, lower maximum dose, tumor progression, and longer follow-up.

Conclusions. Gamma Knife surgery offers an acceptable rate of tumor control for parasellar meningiomas and accomplishes this with a low incidence of neurological deficits. Radiological control after radiosurgery is more likely in those patients with a smaller tumor volume and a higher prescription dose.

J Neurosurg 114:1399–1409, 2011. DOI: 10.3171/2010.11.JNS101193

Although numerous studies have analyzed the role of stereotactic radiosurgery for intracranial meningiomas, few studies have assessed outcomes of posterior fossa meningiomas after stereotactic radiosurgery. In this study, the authors evaluate the outcomes of posterior fossa meningiomas treated with Gamma Knife surgery (GKS). The authors also assess factors predictive of new postoperative neurological deficits and tumor progression.

Methods. A retrospective review was performed of a prospectively compiled database documenting the outcomes of 152 patients with posterior fossa meningiomas treated at the University of Virginia from 1990 to 2006. All patients had a minimum follow-up of 24 months. There were 30 males and 122 females, with a median age of 58 years (range 12–82 years). Seventy-five patients were treated with radiosurgery initially, and 77 patients were treated with GKS after resection. Patients were assessed clinically and radiographically at routine intervals following GKS. Factors predictive of new neurological deficit following GKS were assessed via univariate and multivariate analysis, and Kaplan-Meier analysis and Cox multivariate regression analysis were used to assess factors predictive of tumor progression.

Results. Patients had meningiomas centered over the tentorium (35 patients, 23%), cerebellopontine angle (43 patients, 28%), petroclival region (28 patients, 18%), petrous region (6 patients, 4%), and clivus (40 patients, 26%). The median follow-up was 7 years (range 2–16 years). The mean preradiosurgical tumor volume was 5.7 cm3 (range 0.3–33 cm3), and mean postradiosurgical tumor volume was 4.9 cm3 (range 0.1–33 cm3). At last follow-up, 55 patients (36%) displayed no change in tumor volume, 78 (51%) displayed a decrease in volume, and 19 (13%) displayed an increase in volume. Kaplan-Meier analysis demonstrated radiographic progression-free survival at 3, 5, and 10 years to be 98%, 96%, and 78%, respectively. In Cox multivariable analysis, pre-GKS covariates associated with tumor progression included age greater than 65 years (hazard ratio [HR] 3.24, 95% CI 1.12–9.37; p = 0.03) and a low dose to the tumor margin (HR 0.76, 95% CI 0.60–0.97; p = 0.03), and post-GKS covariates included shunt-dependent hydrocephalus (HR 25.0, 95% CI 3.72–100.0; p = 0.001). At last clinical follow-up, 139 patients (91%) demonstrated no change or improvement in their neurological condition, and 13 patients showed symptom deterioration (9%). In multivariate analysis, the only factors predictive of new or worsening symptoms were clival or petrous location (OR 4.0, 95% CI 1.1–13.7; p = 0.03).

Conclusions. Gamma Knife surgery offers an acceptable rate of tumor control for posterior fossa meningiomas and accomplishes this with a low incidence of neurological deficits. In patients selected for GKS, tumor progression is associated with age greater than 65 years and decreasing dose to the tumor margin. Clival- or petrous-based locations are predictive of an increased risk of new or worsening neurological deficit following GKS.

J Neurosurg 114:1241–1249, 2011.DOI: 10.3171/2010.10.JNS101128

The aim of this study was to describe the surgical technique used for removal of sphenoorbital meningiomas in the authors’ practice and to review the operative outcome.

Methods. Review of the senior author’s practice between 1994 and 2009 revealed 39 patients (mean age 48 years) eligible for this study. Clinical presentation, surgical technique, postoperative outcome, and follow-up data are presented. Surgical technique is detailed, with an emphasis on aggressive removal consisting of drilling of the hypertrophied sphenoid bone, orbital wall, and anterior clinoid process, followed by tumor removal and a wide resection of the involved dura. A simple dural closure without reconstruction of the orbital roof or the lateral wall of the orbit is also described.

Results. Gross-total resection was achieved in 15 cases (38.5%), near-total resection with small residual in the cavernous sinus or periorbita in 20 cases (51.3%), and subtotal resection in 4 cases (10.3%). Postoperative complications included trigeminal hypesthesia in 9 patients, oculomotor palsy in 3 patients, and seizure in 2 patients. Seven patients had recurrence within the mean follow-up period of 40.7 months. Preoperative visual deficits were present in 21 patients (53.8%). Of these, 14 (66.7%) experienced visual recovery to normal levels postoperatively. Statistical analyses revealed preoperative severe visual deficit and sphenoid bone hypertrophy as an independent risk factor and an independent favorable factor, respectively, for a favorable visual outcome. Proptosis was resolved (≤ 2 mm) in 73.5% of the authors’ patients. No patient had postoperative enophthalmos.

Conclusions. In the authors’ practice, surgery for sphenoorbital meningiomas consists of resection of the orbital/ sphenoid intraosseous, intraorbital, and intradural tumor components. The authors believe that aggressive removal of the orbital/sphenoid intraosseous tumor is critical for a favorable visual outcome and tumor control. Furthermore, satisfactory cosmetic results can be achieved with simple reconstruction techniques as described.

Neurosurg Rev (2011) 34:159–171. DOI 10.1007/s10143-010-0289-y

Trigeminal schwannoma is a mostly benign tumor that can be cured by complete resection. Over the last few decades, several pioneers have developed surgical approaches enabling the total removal of such tumors.

We analyzed 57 patients who underwent radical surgery, including 45 patients who underwent skull base surgery as their initial treatment, for removal of trigeminal schwannomas. Here, we report the surgical management of these cases. Since 1990, all such patients have been treated using three main types of middle fossa skull base approaches, which minimize the exposure of the brain: the anterior transpetrosal approach, subtemporal interdural approach (Dolenc), or a combination of these approaches.

Before 1990, total tumor removal was achieved in only three of eight patients (38%). After 1990, the tumors were totally removed in 43 patients (90%) and were nearly completely removed in an additional three patients (6%). Among the patients who underwent skull base surgery as their initial treatment, a complete resection was achieved in 93% (42/45 patients) of the cases. However, total surgical removal after surgery and Gamma knife surgery was very difficult because of dense adhesions to the brain stem and cranial nerves. No surgery-related mortalities occurred in this series, and the individual KPS scores were more than 90% among the patients who underwent skull base surgery. No recurrences requiring additional surgery have occurred after an average follow-up period of 4.9 years.

Most of the trigeminal schwannomas could be removed totally and safely during a single operation after the introduction of skull base surgery. Therefore, radiosurgery should not be applied as the treatment of first choice for younger patients. A correct anatomical knowledge is critical for minimizing brain exposure and avoiding surgical complications.

J Neurosurg 113:1106–1111, 2010. DOI: 10.3171/2010.3.JNS09513

Resident duty-hours restrictions have now been instituted in many countries worldwide. Shortened training times and increased public scrutiny of surgical competency have led to a move away from the traditional apprenticeship model of training. The development of educational models for brain anatomy is a fascinating innovation allowing neurosurgeons to train without the need to practice on real patients and it may be a solution to achieve competency within a shortened training period. The authors describe the use of Stratathane resin ST-504 polymer (SRSP), which is inserted at different intracranial locations to closely mimic meningiomas and other pathological entities of the skull base, in a cadaveric model, for use in neurosurgical training.

Methods. Silicone-injected and pressurized cadaveric heads were used for studying the SRSP model. The SRSP presents unique intrinsic metamorphic characteristics: liquid at first, it expands and foams when injected into the desired area of the brain, forming a solid tumorlike structure. The authors injected SRSP via different passages that did not influence routes used for the surgical approach for resection of the simulated lesion. For example, SRSP injection routes included endonasal transsphenoidal or transoral approaches if lesions were to be removed through standard skull base approach, or, alternatively, SRSP was injected via a cranial approach if the removal was planned to be via the transsphenoidal or transoral route. The model was set in place in 3 countries (US, Italy, and The Netherlands), and a pool of 13 physicians from 4 different institutions (all surgeons and surgeons in training) participated in evaluating it and provided feedback.

Results. All 13 evaluating physicians had overall positive impressions of the model. The overall score on 9 components evaluated—including comparison between the tumor model and real tumor cases, perioperative requirements, general impression, and applicability—was 88% (100% being the best possible achievable score where the evaluator strongly agreed with the proposed factor). Individual components had scores at or above 80% (except for 1). The only score that was below 80% was related to radiographic visibility of the model for adequate surgical planning (score of 74%). The highest score was given to usefulness in neurosurgical training (98%).

Conclusions. The skull base tumor model is an effective tool to provide more practice in preoperative planning and technical skills.