Meningiomas of the clivus and apical petrous bone. Report of 35 cases

Diverse accessory techniques and working corridors to enhance the retrosigmoid approach: a versatile option for the treatment of meningiomas of the petroclival region

BACKGROUND

Meningiomas of the petroclival region (MPR) are among the most challenging skull base tumors to manage surgically. Historically, their treatment carried high risks and significant mortality due to the complex anatomy and proximity to critical neurovascular structures. Advances in microsurgical techniques and neuroimaging have significantly improved surgical outcomes. The retrosigmoid approach is a well-established technique for accessing the posterior cranial fossa, further enhanced by specific working corridors and accessory techniques.

OBJECTIVE

To illustrate the versatility of the retrosigmoid approach in managing MPR, emphasizing accessory techniques and tailored working corridors to optimize outcomes.

METHODS

Between January 2015 and August 2024, 32 patients with MPR underwent surgical resection using the retrosigmoid approach in the semi-sitting position. Surgical videos were analyzed to identify working corridors and accessory techniques. Preoperative clinical status, extent of resection, and postoperative outcomes were evaluated.

RESULTS

The study included 32 patients (mean age: 56.2 years; 46.9% female). Accessory techniques were used in 28.1% of cases, including suprameatal tubercle drilling (12.5%), tentorial sectioning (9.4%), and petrous apex drilling (6.2%). Working corridors were adapted based on tumor location: the lateral cerebellar corridor alone was used in 37.5%, supracerebellar alone in 12.5%, and both combined in 50%. New or progressive cranial nerve deficits occurred in 18.75% of patients. No major complications, such as cerebrospinal fluid leakage or infections, were reported.

CONCLUSIONS

This study demonstrates how accessory techniques and tailored working corridors enhance the retrosigmoid approach's versatility, establishing it as a safe and effective option for MPR resection.

CLINICAL TRIAL NUMBER

Not applicable.

Abordajes quirúrgicos de los meningiomas petroclivales Parte 2: revisión narrativa y lo que aprendimos con 30 casos

Antecedentes:

La resección quirúrgica de los meningiomas petroclivales es un desafío debido a su ubicación profunda y su relación con las estructuras neurovasculares vitales. Por lo general, son lesiones benignas, pero pueden involucrar o infiltrar huesos en la base del cráneo, la duramadre y el tronco encefálico. Esto hace que la extirpación total sea muy difícil o imposible sin causar déficits neurológicos. El objetivo de este estudio es revisar los abordajes quirúrgicos utilizados para tratar los meningiomas petroclivales y las lecciones que hemos aprendido en el manejo quirúrgico de 30 casos.

Métodos:

Serie de casos de 30 meningiomas petroclivales. Al comienzo de nuestra serie, utilizamos el abordaje petroso para todos los casos, pero con la adquisición de experiencia comenzamos a indicar cada vez más el abordaje retrosigmoideo, reservando los abordajes petrosos y cráneo-orbitocigomático para casos seleccionados.

Resultados:

Debido a la dificultad de acceso, los meningiomas petroclivales generalmente requieren diferentes abordajes quirúrgicos y presentan diferentes dificultades quirúrgicas. Hay tres abordajes principales: fronto-orbito-cigomático y variantes; petroso y variantes; y retrosigmoideo, pudiendo ser combinados. La elección del abordaje quirúrgico generalmente se basa en la ubicación y extensión del tumor, la forma del cráneo y la participación de las estructuras venosas, y la experiencia del cirujano.

Conclusión:

Los meningiomas petroclivales son raros y complejos en la base del cráneo. Elegir el abordaje correcto es crucial para un resultado quirúrgico exitoso.

Abordajes quirúrgicos de meningiomas petroclivales parte 1: anatomía microquirúrgica

Antecedentes:

Los meningiomas petroclivales son tumores benignos cuyo tratamiento microquirúrgico es uno de los mayores retos de la neurocirugía. El conocimiento profundo de la anatomía microquirúrgica y los abordajes quirúrgicos para el tratamiento de estos tumores es la primera etapa de aprendizaje para un manejo ideal. Este artículo se divide en dos partes: la primera parte presentará los resultados de la anatomía microquirúrgica relevantes para el manejo de los meningiomaspetroclivales. En la segunda parte, los autores correlacionan esta anatomía con 30 casos de meningiomas petroclivales operados por el autor principal (GRI).

Métodos:

Se disecaron ocho cabezas de cadáveres utilizando un microscopio quirúrgico en el laboratorio de microcirugía de la University of Arkansas for Medical Sciences. En los cerebros y en todas las cabezas, se inyectó silicona de colores para resaltar la diferencia entre las arterias y las venas. Los cadáveres fueron colocados en un fijador craneal tipo Mayfield, simulando el posicionamiento quirúrgico de los abordajes craneo-órbito-cigomatico, petrosectomía anterior y posterior y retrosigmoideo. Otras ocho cabezas de cadáveres fueron formolizadas y con los vasos inyectados con silicona de colores. Se realizaron los abordajes petroso anterior, petroso posterior y craneo-órbito-cigomático.

Resultados:

En el manejo de los meningiomas petroclivales se utilizan tres abordajes quirúrgicos principales: abordaje pterional y sus variantes, abordaje petroso y sus variantes y abordaje retrosigmoideo. Los abordajes endonasales endoscópicos extendidos tienen factores limitantes para su uso en este tipo de procedimiento. Para racionalizar la elección del abordaje quirúrgico, dividimos el clivus en tercios superior, medio e inferior.

Conclusíon:

Varios abordajes quirúrgicos dan acceso a la regiónpetroclival. El conocimiento práctico de la anatomía de esta región adquirido en el laboratorio de microcirugía es parte fundamental del cirujano que se propone operar meningiomas petroclivales.

Stereotactic radiosurgery in the management of petroclival meningiomas: a systematic review and meta-analysis of treatment outcomes of primary and adjuvant radiosurgery

PURPOSE

To summarize the clinical features and outcomes of petroclival meningioma patients treated with stereotactic radiosurgery (SRS) as either a primary or an adjuvant modality.

METHODS

Relevant articles were retrieved from PubMed, Scopus, Web of Science, and Cochrane. A systematic review and meta-analysis of treatment outcomes comparing primary and adjuvant SRS was conducted.

RESULTS

Seven articles comprising 722 cases were included. The mean tumor marginal dose was 13.5 Gy. After SRS, symptoms improved in 28.7%, remained unchanged in 61.3%, and worsened in 10.0% of the cohort. Tumor control was achieved in 94.8% of patients. The mean tumor volume change was -6.4 cm3. The 5-year and 10-year progression-free survival (PFS) rates were 91-100% and 69.6-89.9%, respectively. Overall, 61.9% of patients underwent primary radiosurgery, and 38.1% had adjuvant radiosurgery. Patients who had primary SRS reported higher rates of tumor control (94.3% vs. 88.2%) and fewer SRS-related complications (3.7% vs. 10.3%) than those who received adjuvant SRS (not accounting for microsurgical complications). The functional status of patients who had primary SRS was more likely to improve or remain unchanged, with an effect size of 1.12 (95% CI 1.1-1.25; I2 = 0). Neither group displayed superiority in worsening functional outcomes or tumor control rate.

CONCLUSION

SRS of petroclival meningiomas was associated with excellent long-term PFS and local tumor control rates. Primary SRS was highly effective for patients with smaller volume lesions without clinically symptomatic mass effect. In patients who warrant initial resection, adjuvant radiosurgery remains an important modality to prevent regrowth while maintaining postresection function.

Does general comorbidity impact the postoperative outcomes after surgery for large and giant petroclival meningiomas?

We assessed the role of the general condition of the patient in addition to usual anatomical reasoning to improve the prediction of personalized surgical risk for patients harboring a large and giant petroclival meningiomas. Single-center, retrospective observational study including adult patients surgically treated for a large and giant petroclival meningioma between January 2002 and October 2019 in a French tertiary neurosurgical skull-base center by one Neurosurgeon. Inclusion criteria were as follows: (1) histopathologically proven meningioma; (2) larger than 3 cm in diameter; (3) located within the upper two-thirds of the clivus, the inferior petrosal sinus, or the petrous apex around the trigeminal incisura, medial to the trigeminal nerve. Clinical and radiological characteristics were gathered preoperatively including ASA score, the modified frailty index, and the Charlson comorbidity index. Post-operative severe neurological and non-neurological complications were collected. A total of 102 patients harboring a large and giant petroclival meningioma were included. The rate of postoperative death was 3.0% related to a congestive heart failure (n = 1), a surgical site hematoma (n = 1), and an ischemic stroke (n = 1). A severe neurological impairment was found in 12.8% and a severe non-neurological morbidity was found in 4.0%. The overall rate of severe morbidity and mortality was 15.7% after large and giant petroclival meningioma surgery. The presence of brainstem peri-tumoral edema (adjusted OR, 4.83 [95% CI 1.84-7.52], p = 0.028) was independently associated with a history of postoperative severe neurological morbidity. Male gender (adjusted OR, 7.42 [95% CI 1.05-49.77], p = 0.044), major cardiovascular morbidity (adjusted OR, 9.5 [95% CI 1.05-86.72], p = 0.045), and an ASA score ≥ 2 (adjusted OR, 11.09 [95% CI 1.46-92.98], p = 0.038) were independently associated with a history of postoperative severe non-neurological morbidity. A modified frailty index ≥ 1 (adjusted OR, 3.13 [95% CI 1.07-9.93], p = 0.047) and a low neurosurgical experience (adjusted OR, 5.38 [95% CI 1.38-20.97], p = 0.007) were independently associated with a history of postoperative overall morbidity and mortality. Pre-operative cranial nerve deficits (adjusted OR, 4.77 [95% CI 1.02-23.31], p = 0.024) and gross total resection (adjusted OR, 10.72 [95% CI 1.72-66.90], p = 0.022) were independently associated with postoperative new cranial nerve deficits. This study suggests to add scores assessing the patient general condition in daily practice to improve the selection of patients eligible for surgery. Collaborative international multicenter studies will be necessary to confirm these results and allow their implementation in clinical routine.

Petroclival meningiomas: update of current treatment and consensus by the EANS skull base section

BACKGROUND

The optimal management of petroclival meningiomas (PCMs) continues to be debated along with several controversies that persist.

METHODS

A task force was created by the EANS skull base section along with its members and other renowned experts in the field to generate recommendations for the management of these tumors. To achieve this, the task force reviewed in detail the literature in this field and had formal discussions within the group.

RESULTS

The constituted task force dealt with the existing definitions and classifications, pre-operative radiological investigations, management of small and asymptomatic PCMs, radiosurgery, optimal surgical strategies, multimodal treatment, decision-making, and patient's counselling.

CONCLUSION

This article represents the consensually derived opinion of the task force with respect to the management of PCMs.

Differences in surgical outcome between petroclival meningioma and anterior petrous meningioma

BACKGROUND

Petroclival meningiomas (PC MNGs) and anterior petrous meningiomas (AP MNGs) have similar locations. However, these are different tumors clearly divided by the trigeminal nerve. There has never been a study on the comparison of the surgical outcomes of these two meningiomas. In this study, we compared and analyzed the surgical outcome of PC MNGs and AP MNGs.

METHODS

The charts of 85 patients diagnosed with PC MNGs of AP MNGs who underwent surgical treatment were retrospectively reviewed. And we analyzed the characteristics of 49 PC MNGs (57.6%) and compared them with those of 36 AP MNGs.

RESULTS

Preoperative brainstem edema was observed in 11 patients (22.4%) of the PC MNG group and 1 patient (2.8%) of the AP MNG group (p = 0.024). Total tumor removal was achieved in 21 patients (58.3%) of the AP MNG group, but only 17 patients (34.7%) of the PC MNG group were able to completely (p = 0.047). In addition, sixth cranial nerve palsy occurred in 17 patients (34.7%) of the PC MNG group and 4 patients (11.1%) of the AP MNG group (p = 0.025).

CONCLUSIONS

In this study, we found that PC MNGs has a worse surgical outcome than AP MNGs, because PC MNGs were difficult to completely remove and were more likely to damage abducens nerve.

Long-term outcomes of patients with unresectable benign meningioma treated with proton beam therapy

This study aimed to evaluate the long-term efficacy of proton beam therapy (PBT) for unresectable benign meningiomas at the University of Tsukuba, Japan. From 1986-1998, 10 patients were treated at the Particle Radiation Medical Science Center (PRMSC) with a relative biological effectiveness (RBE) value of 1.0 using an accelerator built for physics experiments. The total dose was compensated with an X-ray in three patients. Following that, from 2002-2017, 17 patients were treated with a RBE value of 1.1 at the Proton Medical Research Center (PMRC) which was built for medical use. At the PRMSC, the total dose ranged from 50.4-66 Gy (median: 54 Gy). During the follow-up, which lasted between 3.8 and 31.6 years (median: 25.1 years), the 5-, 10-, 15-, 20- and 30-year local control rates were 100%, and the 5-, 10-, 15-, 20- and 30-year survival rates were 90, 80, 70, 70 and 36%, respectively. One patient died of brainstem radiation necrosis 5.1 years after PBT. At PMRC, the total dose ranged from 45.0-61.2 GyE, with a median of 50.4 GyE. During the follow-up, which lasted between 3 and 17 years with a median of 10.5 years, the 5-, 10- and 15-year local control rates were 94.1%, and the 5-, 10- and 15-year survival rates were 100, 100 and 88.9%, respectively. Neither malignant transformation nor secondary malignancy was observed, indicating that fractionated PBT may be effective and safely control benign unresectable meningioma even for the lifelong period of time.

Analysis of Approaches in the Microsurgical Treatment of 102 Cases of Petroclival Meningioma in a Single Center

Objectives: We identified the optimal approaches for treating the diverse tumor subtypes of petroclival meningioma (PM) by analyzing the clinical benefits of various surgical approaches adopted for each subtype. Methods: Tumors in 102 PM patients from a single center who underwent surgical treatment were classified as upper clivus (UC), cavernous sinus (CS), tentorium (TE), or petrous apex (PA) types based on the attachment site of the tumor base and the displacement of the trigeminal nerve. The therapeutic effects of different surgical approaches among the subtypes were evaluated according to the patient outcomes. Results: The subtemporal (33.33%), retrosigmoid (16.67%), and Kawase approaches (50%) were used for the UC type. Simpson I/II resection was achieved in 46.66% of patients with the Kawase approach. Significant differences were found between the other two approaches (P = 0.044) and in the follow-up Karnofsky performance scale (KPS) scores (P = 0.008). The subtemporal (60%) and Kawase approaches (40%) were used for the CS type; neither approach achieved Simpson I/II resection. The retrosigmoid (25.81%) and Kawase approaches (74.19%) were used for the TE type. The Simpson I/II resection rates of the two approaches were 55.55 and 86.95%, respectively, and a significant difference was observed between them (P = 0.039). The retrosigmoid (43.75%) and Kawase approaches (56.25%) were used for the PA type. The Simpson I/II resection rates of the two approaches were 31.25 and 50%, respectively. The resection degrees of the two approaches and the KPS scores at follow-up were significantly different (P = 0.034). Conclusion: The individual microsurgical approaches adopted for the various PM tumor subtypes can provide maximal safe resection and good KPS scores. The Kawase approach is more suitable for PM, especially for UC- and PA-type PM tumors.

Petroclival meningiomas and the petrosal approach

As with other meningiomas, the goal of petroclival meningioma treatment should be curative total removal by achieving a Simpson I resection of the tumor, dura, and bone. Petroclival meningiomas particularly pose a great technical challenge because of their deep location and intimate relation with vital neurovascular structures. They require adequate exposure and trajectory to achieve total removal while minimizing the manipulation and risk to critical neurovascular structures, such as the vertebrobasilar system, the brainstem, and the cranial nerves. Here, we describe the indications and technical nuances of the posterior and combined posterior-anterior petrosal approaches for petroclival meningiomas.

The historical perspective in approaches to the spheno-petro-clival meningiomas

The current literature regarding surgical treatment for tumors in the sphenopetroclival (SPC) region is merely scarce. Through a comprehensive literature review, we investigated the indications, outcomes, and complications of different surgical approaches to the SPC meningiomas. Given its complicated relationship between these slow-progression tumors and some critical neurovascular structures in the SPC region, surgical treatment of these tumors faces the challenge of achieving a maximal grade of resection, while preserving patient functionality. The development of new surgical techniques and approaches in recent years have permitted the advancement in the treatment of these tumors, with acceptable rates of morbidity and mortality. The choice of a surgical approach as a treatment for the lesion depends mainly on the type of tumor extension, surgeon's preferences, and the displacement of neurovascular structures. Rather than focusing on one single strategy of treatment, the skull-base surgeon should tailor the approach based on the origin and features of the lesion; as well as the peculiarities of the surgical anatomy. This strategy aims to decrease morbidity and to optimize tumor resection and patient quality of life.

Tumor Progression Following Petroclival Meningioma Subtotal Resection: A Volumetric Study

BACKGROUND

One study has investigated postoperative growth rates following subtotal resection of petroclival meningiomas utilizing linear measurements, which are insensitive to the multidimensional complex growth of meningiomas, to estimate tumor volume.

OBJECTIVE

To describe petroclival meningioma growth patterns following less-than-complete resection utilizing volumetric analysis and to identify variables associated with tumor progression.

METHODS

Patients with surgically resected WHO grade I petroclival meningiomas were retrospectively reviewed (1999-2015). Image analysis software was utilized to perform volumetric analyses of tumor size and growth on serial MRI studies. The impact of preoperative and postoperative variables on tumor growth after subtotal resection was analyzed. An increase in tumor volume of at least 20% was defined as "tumor growth."

RESULTS

Twenty-three patients had immediate preoperative and serial postoperative MRI studies available for review. The mean preoperative tumor volume was 20.9 cm3 (range 0.4-54.6). The mean extent of resection was 75.5% (range 31.5%-100.0%). At a mean follow-up of 24.8 mo, 12 tumors (66.7%) exhibited radiological tumor growth, while 6 tumors did not change in size. The median annual volumetric growth rate was 2.82 cm3/yr (range -0.34 to 10.1). Extent of resection and immediate postoperative tumor volume were significantly correlated with the annual volumetric growth rate following resection. At last follow-up, 3 (13%) patients required further intervention.

CONCLUSION

The majority of petroclival meningiomas exhibit growth following subtotal resection. Extent of resection is strongly associated with risk for disease progression following surgery.

Clinical outcomes and survival analysis for petroclival meningioma patients receiving surgical resection: an analysis of 176 cases

Purpose: The relationship of clinical results and survival analysis of operative patients with petroclival meningioma (PCM) was studied.

Patients and methods: Data from a total of 176 PCM patients receiving surgical resection were retrospectively collected. Follow-up was conducted through outpatient review by reexamination telephone calls and letters. Clinical outcomes, survival, and Karnofsky Performance Scale (KPS) data were analyzed.

Results: Seventy-two percent of patients (127/176) received only surgery, 8.5% (15/176) received surgery and adjuvant radiation therapy (RT) (surgery + RT), and 19.3% (34/176) received surgery and adjuvant gamma knife surgery (GKS) (surgery + GKS). Gross total resection (GTR) was performed in 34.7% of patients (61/176), subtotal resection (STR) in 58.0% (102/176), and partial resection (PR) in 7.4% (13/176). Recent follow-up KPS was higher than preoperative (80 vs 70, P<0.05) and postoperative KPS (80 vs 70, P<0.05). Cumulative survival was the same for 3, 5, 7, and 9 years, ie, 95%, and mean survival time (MST) was (110.83±2.55) months (95% CI: 105.83–115.83). Recurrence/progression (R/P)-free survival was 88.9%, 86.9%, 71.1% and 71.1%, respectively for 3, 5, 7, and 9 years, and MST was (100.58±3.82) months (95% CI: 93.11–108.06). R/P (HR: 5.486, 95% CI: 1.655–18.180), surgery + RT (HR: 0.125, 95% CI: 0.016–0.990) and WHO grade III (HR: 2.766, 95% CI: 1.146–6.676) were independently associated with cumulative survival. Lack of adhesion to and encasement of neurovascular structures was independently associated with R/P-free survival (HR: 2.002, 95% CI: 1.023–3.919).

Conclusion: Surgical treatment was safe and effective for PCM. R/P, surgery + RT, and WHO grade III were independently associated with cumulative survival. Lack of adhesion to and encasement of neurovascular structures was independently associated with R/P-free survival. These factors should be paid attention to in surgical treatment of PCM.

Petroclival meningiomas: radiological features essential for surgeons

Petroclival meningiomas (PCMs) have always been a challenge for surgeons because of their difficult anatomical location. The role of radiology in providing precise indications regarding the tumour site and aggressiveness plays a major part in guiding the subsequent therapeutic process. The purpose of this review is to provide a set of the main radiological features helpful in the management of PCMs towards the most correct therapeutic approach.

We aim to offer a radiological overview to allow the patient to be directed to surgery with the least possible risk of complications.

Volumetric changes and clinical outcome for petroclival meningiomas after primary treatment with Gamma Knife radiosurgery

OBJECTIVEPetroclival meningiomas (PCMs) can cause devastating clinical symptoms due to mass effect on cranial nerves (CNs); thus, patients harboring these tumors need treatment. Many neurosurgeons advocate for microsurgery because removal of the tumor can provide relief or result in symptom disappearance. Gamma Knife radiosurgery (GKRS) is often an alternative for surgery because it can cause tumor shrinkage with improvement of symptoms. This study evaluates qualitative volumetric changes of PCM after primary GKRS and its impact on clinical symptoms.METHODSThe authors performed a retrospective study of patients with PCM who underwent primary GKRS between 2003 and 2015 at the Gamma Knife Center of the Elisabeth-Tweesteden Hospital in Tilburg, the Netherlands. This study yields 53 patients. In this study the authors concentrate on qualitative volumetric tumor changes, local tumor control rate, and the effect of the treatment on trigeminal neuralgia (TN).RESULTSLocal tumor control was 98% at 5 years and 93% at 7 years (Kaplan-Meier estimates). More than 90% of the tumors showed regression in volume during the first 5 years. The mean volumetric tumor decrease was 21.2%, 27.1%, and 31% at 1, 3, and 6 years of follow-up, respectively. Improvement in TN was achieved in 61%, 67%, and 70% of the cases at 1, 2, and 3 years of follow-up, respectively. This was associated with a mean volumetric tumor decrease of 25% at the 1-year follow-up to 32% at the 3-year follow-up.CONCLUSIONSGKRS for PCMs yields a high tumor control rate with a low incidence of neurological deficits. Many patients with TN due to PCM experienced improvement in TN after radiosurgery. GKRS achieves significant volumetric tumor decrease in the first years of follow-up and thereafter.

Treatment of Lateral Skull Base and Posterior Cranial Fossa Lesions Utilizing the Extended Middle Cranial Fossa Approach

OBJECTIVE

Define the indications and outcomes for subjects undergoing treatment utilizing the extended middle cranial fossa approach (EMCF).

STUDY DESIGN

Retrospective records review.

SETTING

University-based tertiary referral center.

PATIENTS

Subjects undergoing treatment of posterior cranial fossa (PCF) lesions.

INTERVENTION(S)

EMCF exposure and treatment of the indicating PCF lesion.

MAIN OUTCOME MEASURE(S)

Demographic, audiometric, and cranial nerve functioning variables were assessed.

RESULTS

Thirty-five subjects who underwent an EMCF exposure were identified over a 12-year period. The most common indication was meningioma (18; 51%) followed by schwannomas (six, 17%), and vascular lesions (five, 14%). Preoperative cranial nerve complaints were common (32, 94%) as were objective cranial nerve abnormalities on physical examination (21; 60%). Preoperative audiometric data from subjects with hearing demonstrated good functioning including pure-tone average (PTA) (21.7 ± 15.6 dB HL) and word understanding scores (95.1 ± 7.4%). Most (34, 97%) subjects had intact facial nerve function. The average length of stay was 11.6 days (median = 9). Cranial neuropathies were common postoperatively with 27 (79%) subjects demonstrating some objective cranial nerve dysfunction, the most common of which was trigeminal nerve hypesthesia (21, 61.7%). Subjects with identifiable pre- and postoperative audiometric data and preoperative hearing demonstrated small declines in the four-tone average (16.2 dB) and word recognition scores (22.4%). Two subjects (6%) had new profound hearing loss postoperatively.

CONCLUSIONS

The EMCF approach can provide safe and effective exposure of the anterior PCF.

Petroclival Meningiomas: Factors Determining the Choice of Approach

Objectives  To review a surgical series of petroclival meningiomas and the factors considered in the choice of approach. Design  Retrospective review. Setting  The study was conducted in a university hospital in southern Brazil. Participants  Twenty-two patients with petroclival meningioma originating from the upper two-thirds of the clivus medial to the fifth cranial nerve. Main Outcome Measures  Gross-total resection, mortality, major morbidity, new cranial nerve deficits and tumor progression or recurrence. Results  Retrosigmoid approach was used in tumors <3 cm and in those at or below the internal auditory meatus. Posterior petrosectomy was performed for tumors extending into the middle fossa. Gross-total resection was performed in 11 patients (50%). The mean follow-up time was 32 months (6-75 months). There were four cases of tumor progression or recurrence, which were treated with radiosurgery. Conclusions  Resection of petroclival meningiomas remains challenging. In most cases, the retrosigmoid approach was sufficient, without affecting the degree of tumor resection. Petrosal approaches were reserved for patients with tumor extension into the middle fossa.

Petroclival meningiomas: Remaining controversies in light of minimally invasive approaches

Surgical resection of petroclival meningiomas remains challenging due to their deep location and relationship to vital neurovascular structures. Although the natural history of these tumors involves a slow course, the incidence of cranial nerve deficits and the extent of tumor resection vary widely in the literature. Some reviews on this topic have been conducted, but data remain fragmentary and based on retrospective case series, which hinders attempts at meta-analysis. Within this context, research into the use of minimally invasive approaches, including in neuroendoscopy, continues to emerge. The objective of this narrative review is to analyze the available literature on the surgical treatment of petroclival meningiomas, with a focus on attempts at endoscopy-assisted resection.

Surgical Resectability of Skull Base Meningiomas

With recent advances in surgical technology such as preoperative imaging, neuro-monitoring, and surgical instruments, the surgical resectability of intracranial meningiomas has increased over the last two decades. This study reviewed clinical articles regarding the surgical treatment of meningiomas to clarify the role of surgical excision, with a focus on skull base meningiomas. We sub-classified clinical articles about skull base meningiomas into two categories (anterior and middle fossa meningiomas; and posterior fossa meningiomas) and reviewed papers in each category. In cases with anterior and middle fossa meningiomas, surgical resectability has reached a sufficient level to maximize functional preservation. In cases of posterior fossa meningioma, however, surgical respectability remains insufficient even with full use of recent surgical modalities. Continuous refining of operative procedures is required to obtain more satisfactory outcomes, especially for posterior fossa meningioma. In addition, recent long-term outcomes of stereotactic radiosurgery (SRS) were acceptable for controlling the skull base meningiomas. Therefore, combination with surgical excision and SRS should be considered in complicated skull base meningiomas.

Venous Thromboembolism and Malignant Brain Tumors: A Review

The incidence of venous thromboembolism (VTE) in patients with primary brain tumors varies be tween 1 and 60%. This variability in incidence is due to study differences in (a) methods of diagnosis of VTE— i.e., diagnosis at autopsy or clinical diagnosis; (b) amount of time from surgery to VTE diagnosis; (c) proportion of patients receiving deep venous thrombosis (DVT) pro phylaxis ; (d) clinical risk factors associated with VTE, such as paresis, prior thrombotic disease, and chemother apy; and (e) tumor location and histology. The etiology of VTE in patients with primary brain tumors is unknown. The preoperative hemostatic abnormalities noted in clin ical studies have been most consistent with compensated disseminated intravascular coagulation (DIC). These ab normalities, however, appear to be of little predictive value for the subsequent development of VTE. Studies involving brain tumor tissue or cell cultures have impli cated factors released by the tumor or surrounding neural tissue that activate the coagulation system or inhibit fi brinolysis. Recommendations for VTE prophylaxis in clude (a) earliest possible ambulation; (b) intermittent pneumatic compression in all nonambulatory patients preoperatively and postoperatively; and (c) s.c. heparin in high-risk patients. The role of low-molecular-weight heparin in VTE prophylaxis has not been established. Patients with malignant brain tumors can be safely anti coagulated with heparin and warfarin if these agents are carefully monitored. Of 197 patients in seven series who received anticoagulants, only 5 (2.5%) had intracranial bleeding. Vena caval filters and thrombectomy are rarely required. Thrombolytic therapy is contraindicated. Key Words: Venous thromboembolism—Deep venous throm bosis—Malignant brain tumors.

Pre-Operative Angiography and Embolisation of Petroclival Meningiomas

We reviewed our experience of 15 patients with petroclival meningiomas who underwent pre-operative angiography, 11 of whom were embolised in the same session.

We analysed our cases to evaluate the variations in vascular supply to these tumours, their potential for embolisation, and the techniques used for their devascularization; as well as associated MRI findings.

The petroclival region is vascularised by the basal tentorial arcade. Petroclival meningiomas derive their blood supply from the ICA and ECA branches which form this network, and may also parasitize supply from the vertebrobasilar system. ICA (meningohypophyseal trunk) supply was present in all our patients, and 93% also had ECA contributions (basal tentorial branches of the middle and accessory meningeal arteries, the ascending pharyngeal artery, the artery of foramen rotundum and transmastoid branches of the occipital artery). 47% had pial supply from the vertebrobasilar system.

The ECA supply was partly or completely embolised in each of the 11 patients, and the meningohypophyseal contribution in one; there were no complications. Pre-operative angiographic assessment of patients with petroclival meningiomas provides important information for determining the surgical approach, and when combined with embolisation may facilitate a more complete resection of these surgically challenging lesions.

Surgical management of medium and large petroclival meningiomas: a single institution's experience of 199 cases with long-term follow-up

BACKGROUND

Petroclival meningiomas (PCMs) were once regarded as 'inoperable' due to their complex anatomy and limited surgical exposure. This study aimed to evaluate the long-term outcomes of surgically treated PCMs larger than 2 cm.

METHODS

A series of 199 consecutive patients (137 females, 68.8 %) with PCMs larger than 2 cm from between 1993 and 2003 were included. The clinical charts, radiographs, and follow-ups were evaluated.

RESULTS

Gross total resection (GTR) was achieved in 111 (55.8 %) patients, subtotal resection (STR) in 65, and partial resection (PR) in 23. Cranial nerve dysfunctions were the most common complications and occurred in 133 (66.8 %) cases. The surgical mortality was 2.0 %. The Karnofsky Performance Scale (KPS) scores significantly decreased 1 month after the operations (preoperative KPS = 76.8 and postoperative KPS = 64.8; p = 0.011, Paired-samples t test). Long-term follow-ups were obtained in 142 patients, the follow-up duration was 171.6 months, and the most recent KPS was 83.2. Permanent morbidities remained in 24 patients (18.9 %). Multivariate analysis revealed that brainstem edema and tumors larger than 4 cm in diameter were independent risk factors in terms of outcomes (KPS < 80). The recurrence/progression rates were 14.5, 31.8, and 53.3 % for the GTR, STR, and PR cases, respectively (p = 0.002, Pearson χ (2) test). Gamma Knife radiosurgery for the remnants exhibited good tumor control.

CONCLUSIONS

Favorable outcomes and low mortality were achieved with the microsurgical management of medium and large PCMs; however, the rates of cranial nerves dysfunction remained high. Radically aggressive resection might not be judicious in terms of postoperative morbidity. The preoperative evaluations and intraoperative findings were informative regarding the outcomes. The low follow-up rate likely compromised our findings, and additional consecutive studies were required.

Pathological Location of Cranial Nerves in Petroclival Lesions: How to Avoid Their Injury during Anterior Petrosal Approach

Objectives Numerous surgical approaches have been developed to access the petroclival region. The Kawase approach, through the middle fossa, is a well-described option for addressing cranial base lesions of the petroclival region. Our aim was to gather data about the variation of cranial nerve locations in diverse petroclival pathologies and clarify the most common pathologic variations confirmed during the anterior petrosal approach. Method A retrospective analysis was made of both videos and operative and histologic records of 40 petroclival tumors from January 2009 to September 2013 in which the Kawase approach was used. The anatomical variations of cranial nerves IV-VI related to the tumor were divided into several location categories: superior lateral (SL), inferior lateral (IL), superior medial (SM), inferior medial (IM), and encased (E). These data were then analyzed taking into consideration pathologic subgroups of meningioma, epidermoid, and schwannoma. Results In 41% of meningiomas, the trigeminal nerve is encased by the tumor. In 38% of the meningiomas, the trigeminal nerve is in the SL part of the tumor, and it is in 20% of the IL portion of the tumor. In 38% of the meningiomas, the trochlear nerve is encased by the tumor. The abducens nerve is not always visible (35%). The pathologic nerve pattern differs from that of meningiomas for epidermoid and trigeminal schwannomas. Conclusion The pattern of cranial nerves IV-VI is linked to the type of petroclival tumor. In a meningioma, tumor origin (cavernous, upper clival, tentorial, and petrous apex) is the most important predictor of the location of cranial nerves IV-VI. Classification of four subtypes of petroclival meningiomas using magnetic resonance imaging is very useful to predict the location of deviated cranial nerves IV-VI intraoperatively.

MRI as an essential diagnostic approach for trigeminal neuralgia

Trigeminal neuralgia is a well recognised disorder frequently reported to the dentist. The diagnosis of trigeminal neuralgia is primarily based on history and clinical criteria. The clinical findings do not differentiate idiopathic trigeminal neuralgia from symptomatic trigeminal neuralgia. We describe a case of cliviopetrosal meningioma presenting as trigeminal neuralgia and discuss the importance of magnetic resonance imaging as an essential diagnostic approach when trigeminal neuralgia occurs concurrently with a brain tumour.

Surgical management of petroclival meningiomas: Factors affecting early post-operative outcome

INTRODUCTION

Petroclival meningiomas pose a major challenge to the treating neurosurgeon. The philosophy of treatment has changed over the decades from a nihilistic attitude to that of aggressive total excision to now a more tempered, maximal safe excision preventing morbidity followed by adjuvant treatment. Despite the advances in neurosurgery, surgical management of these tumours is still associated with sizable morbidity and mortality.

MATERIAL AND METHODS

This is a retrospective study of surgically managed petroclival meningiomas at our institute. Clinical status, radiological features and surgical outcome were analysed.

RESULTS

Between January 2003 and August 2013, we have operated on 30 patients. The most common presenting complaints were varying degrees of cranial nerve involvement and cerebellar dysfunction. Surgery was done using one of the skull base approaches with the retrosigmoid approach being used maximally (22 cases). Total or near-total excision was possible in 11 cases. There was a post-operative deterioration in cranial nerve functions in all patients and deterioration in Karnofsky Performance Score in seven patients at discharge. Three improved to independent status on follow-up. There was mortality in two cases. Overall 23 of the 30 patients (76.6%) had favourable outcomes.

CONCLUSIONS

These are challenging tumours to treat and are associated with sizable morbidity and mortality. On statistical analysis, we found that if the tumour has a size of 3-5 cm and petroclival in location with no sphenoid extension and the lesion is homogenous on T2-weighted images, then there was a trend towards gross total resection and favourable outcome.

Surgery of petroclival meningiomas. Recent surgical results and outcomes

Petroclival meningiomas represent only 10% of all meningiomas located in the posterior fossa, but are some of the most formidable challenges in skull base surgery. We described our recent experience (2005-September2014) regarding the surgery of these tumors. We retrospectively analyzed surgical results and outcome in 11 cases of petroclival meningiomas. Most common symptoms in our series were headache and gait disturbance, while cranial nerves palsies represented the most common presenting signs. There were 8 females and 3 males, and the mean age was 52 years. Surgical approaches chosen for petroclival meningiomas in our series were retrosigmoid (9 patients) and subtemporal transtentorial (2 patients). We achieved total tumor resection in 5 cases (45%) and subtotal resection in 6 cases (55%). Overall outcome (total/subtotal resection) was good in 6 cases, fair in 3 cases and poor in one case. One postoperative death occurred due to hemorrhagic midbrain infarction (9%). Complications were usually related to cranial nerve deficits: loss of hearing (2 patients), paresis of trochlear nerve (1 patient), trigeminal nerve (3 patients) and facial nerve (1 patient). In 4 patients these cranial nerves deficits were transient. In one case, a patient developed postoperative hydrocephalus and needed shunt placement. Despite the fact that complications can be disastrous, we considered that an appropriate approach, combined with microsurgical techniques and a better understanding of the anatomy, greatly decrease the incidence and severity of complications and make feasible a total tumor resection.

Recurrent petroclival meningiomas: clinical characteristics, management, and outcomes

This study seeks to elucidate the prognostic predictors and outcomes of recurrent/progressive petroclival meningiomas (PCMs). We reviewed our cohort of 39 recurrent/progressive PCMs (27 females, 69.2%) and analyzed the results from the literature. Twenty-three patients underwent reoperations, 2 received radiotherapy alone, and 14 declined any treatment. During a follow-up of 70.4 months, 7 patients experienced a 2nd recurrence/progression (R/P) and 18 patients died. In the 23 patients, gross total resection (GTR), subtotal resection (STR), and partial resection (PR) were achieved in 8, 8, and 7 patients, respectively. The percentage of the 2nd R/P-free survival of GTR, STR, and PR was 88%, 67%, and 40%, respectively. The overall survival following the 1st R/P of GTR, STR, and PR was 88%, 63%, and 33%, respectively. Patients rejecting treatment suffered from significantly poor overall survival (7%; p = 0.001) and short survival duration (42.0 months; p = 0.016) compared with that of the patients receiving treatment (67% and 86.9 months). The GTR was the only independent favorable predictor. In the 21 included studies with 98 recurrent/progressive PCM patients, 17 patients presented with a 2nd R/P and 10 died of a 2nd R/P; patients undergoing observation had a significantly poor tumor regrowth control rate compared with patients undergoing surgery (p = 0.004) or radiotherapy alone (p < 0.001). Proactive treatment should be performed for patients with recurrent/progressive PCMs. Observation can lead to relentless outcome. GTR as a preferential therapeutic strategy should be pursued as far as possible on the condition of minimal functional impairment.

Management of petroclival meningiomas: a review of the development of current therapy

The surgical management of petroclival meningioma remains challenging, due to the difficulty of accessing the region and the vital structures adjacent to the origin of these tumors. Petroclival meningiomas were originally considered largely unresectable. Until the 1970s, resection carried a 50% mortality rate, with very high rates of operative morbidity if attempted. However, in the past 40 years, advances in neuroimaging and approaches to the region were refined, and results from resection of petroclival meningiomas have become more acceptable. Today, the developments of a multitude of surgical approaches as well as innovations in neuroimaging and stereotactic radiotherapy have proved powerful options for multimodality management of these challenging tumors.

Surgical Experience of Infratentorial Meningiomas : Clinical Series at a Single Institution during the 20-Year Period

Objective

Based on surgical outcomes of patients with infratentorial meningiomas surgically treated at our institution, we analyzed the predictors for surgical resection, recurrence, complication, and survival.

Methods

Of surgically treated 782 patients with intracranial meningioma, 158 (20.2%) consecutive cases of infratentorial location operated on between April 1993 and May 2013 at out institute were reviewed retrospectively. The patients had a median age of 57.1 years (range, 16--77 years), a female predominance of 79.7%, and a mean follow-up duration of 48.4 months (range, 0.8--242.2 months).

Results

Gross total resection (Simpson's grade I & II) was achieved in 81.6% (129/158) of patients. Non-skull base location was an independent factor for complete resection. The recurrence rate was 13.3% (21/158) and the 5-, 10-, and 15-year recurrence rates were 8.2%, 12.0%, and 13.3%, respectively. Benign pathology, postoperative KPS over than 90, low peritumoral edema, and complete resection were significantly associated with longer recurrence-free survival rate. The 5-, 10-, and 15-year survival rates were 96.2%, 94.9%, and 94.9%, respectively. Benign pathology, postoperative KPS over than 90 and complete resection were significantly associated with a longer survival rate. The permanent complication rate was 13% (21/158). Skull base location and postoperative KPS less than 90 were independent factors for the occurrence of permanent complication.

Conclusion

Our experience shows that infratentorial meningiomas represent a continuing challenge for contemporary neurosurgeons. Various factors are related with resection degree, complications, recurrence and survival.

True petroclival meningiomas: results of surgical management

OBJECT

The relentless natural progression of petroclival meningiomas mandates their treatment. The management of these tumors, however, is challenging. Among the issues debated are goals of treatment, outcomes, and quality of life, appropriate extent of surgical removal, the role of skull base approaches, and the efficacy of combined decompressive surgery and radiosurgery. The authors report on the outcome in a series of patients treated with the goal of total removal.

METHODS

The authors conducted a retrospective analysis of 64 cases of petroclival meningiomas operated on by the senior author (O.A.) from 1988 to 2012, strictly defined as those originating medial to the fifth cranial nerve on the upper two-thirds of the clivus. The patients' average age was 49 years; the average tumor size (maximum diameter) was 35.48 ± 10.09 mm (with 59 tumors > 20 mm), and cavernous sinus extension was present in 39 patients. The mean duration of follow-up was 71.57 months (range 4-276 months).

RESULTS

In 42 patients, the operative reports allowed the grading of resection. Grade I resection (tumor, dura, and bone) was achieved in 17 patients (40.4%); there was no recurrence in this group (p = 0.0045). Grade II (tumor, dura) was achieved in 15 patients (36%). There was a statistically significant difference in the rate of recurrence with respect to resection grade (Grades I and II vs other grades, p = 0.0052). In all patients, tumor removal was classified based on postoperative contrast-enhanced MRI, and gross-total resection (GTR) was considered to be achieved if there was no enhancement present; on this basis, GTR was achieved in 41 (64%) of 64 patients, with a significantly lower recurrence rate in these patients than in the group with residual enhancement (p = 0.00348). One patient died from pulmonary embolism after discharge. The mean Karnofsky Performance Status (KPS) score was 85.31 preoperatively (median 90) and improved on follow-up to 88, with 30 patients (47%) having an improved KPS score on follow-up. Three patients suffered a permanent deficit that significantly affected their KPS. Cerebrospinal fluid leak occurred in 8 patients (12.5%), with 2 of them requiring exploration. Eighty-nine percent of the patients had cranial nerve deficits on presentation; of the 54 patients with more than 2 months of follow-up, 21 (32.8%) had persisting cranial nerve deficits. The overall odds of permanent cranial nerve deficit of treated petroclival meningioma was 6.2%. There was no difference with respect to immediate postoperative cranial nerve deficit in patients who had GTR compared with those who had subtotal resection.

CONCLUSIONS

Total removal (Grade I or II resection) of petroclival meningiomas is achievable in 76.4% of cases and is facilitated by the use of skull base approaches, with good outcome and functional status. In cases in which circumstances prevent total removal, residual tumors can be followed until progression is evident, at which point further intervention can be planned.

Meningiomas of the upper and middle part of the clivus and surrounding structures: early and long-term outcome

BACKGROUND AND PURPOSE

Meningiomas of the upper and middle parts of the clivus and surrounding structures are removed using petrosal approaches: anterior, posterior, combined and complete. The purpose of this study is to show the results of treatment of these meningiomas and to present our interpretation of the treatment strategy.

MATERIAL AND METHODS

Twenty-six patients (17 women, 9 men) were included in the study. The neurological status of the patients was assessed before and after surgery as well as at the conclusion of the treatment. The following measurements and data were collected and recorded: approximate volume of the treated lesion, its relation to large blood vessels, cranial nerves and the brainstem, as well as tumour consistency and vascularisation.

RESULTS

Symptoms duration ranged from 1 to 60 months (median: 16 months). In 57.7% of patients, imbalance was the predominant sign. Less frequent symptoms were: head-aches, dysacusis and hemiparesis. Approximate volumes of the tumours ranged from 4 to 65 mL (mean: 32 mL). Total or subtotal resection was achieved in 73.1% of patients. The patients' performance improved postoperatively in 34.5%, remained unchanged in 46.2% and deteriorated in 11.5% of patients. Two (7.8%) patients died after the surgery.

CONCLUSIONS

The use of petrosal approaches in the surgical treatment of meningiomas of the upper and middle parts of the clivus and the surrounding structures facilitates good or at least satisfactory neurological outcome with a high proportion of complete resections and relatively low mortality.

Surgical management and outcomes of petroclival meningiomas: a single-center case series of 259 patients

BACKGROUND

Surgical management of petroclival meningiomas is challenging. Various and inconsistent outcome and prognostic factors of the lesions have been evaluated previously. In the present study, the surgical outcome, philosophy, and experience of petroclival meningiomas are detailed based on a large patient series.

METHODS

A series of 259 patients with petroclival meningiomas (70 males and 189 females) were surgically treated. Clinical charts and radiographs were reviewed. Follow-up results were evaluated.

RESULTS

The preoperative Karnofsky Performance Scale (KPS) score was 74.2 ± 10.5. The mean tumor size was 4.3 ± 1.0 cm. The gross total resection (GTR) rate was 52.5%. During a mean follow-up period of 55.3 months, recurrence/progression (R/P) occurred in 11 patients. The recent KPS score was 78.4 ± 22.7, it improved in 139 (57.2%) patients and stabilized in 53 (21.8%) patients, and 201 (82.7%) patients lived independently. The risk factors affecting the KPS score included (but were not limited to) age ≥ 60, preoperative KPS ≤ 60, and brainstem edema. The adverse factors contributing to R/P-free survival included (but were not limited to) non-total resection and the absence of the subarachnoid space. The R/P-free survival rate was 94.5% at 5 years and 91.2% at 9 years. The overall survival rate was 94.7% at 5 years and 94.7% at 9 years.

CONCLUSIONS

Favorable outcomes from petroclival meningiomas could be achieved by microsurgery. Neurological function and quality of life were prioritized, and GTR was attempted. Risk factors should be considered in surgical schemes, and tumor recurrence should be aggressively monitored and treated.

The history of the combined supra- and infratentorial approach to the petroclival region

Lesions of the ventrolateral brainstem, clivus, and cerebellopontine angle pose significant challenges for surgeons, and the rate of morbidity and mortality from classic neurosurgical approaches has proven to be unacceptably high. Early attempts to expose this region consisted primarily of an extended suboccipital craniectomy, with opening of the tentorium and ligation of the sigmoid sinus for additional exposure. During the 1960s, technological innovations including the surgical microscope and the pneumatic drill allowed surgeons to gain additional exposure by removing more bone from the base of the skull. This let surgeons define combined infra- and supratentorial approaches, which rely less on brain retraction to resect these difficult tumors successfully. These approaches rely on a combined posterior mastoid approach with an anterior petrosectomy. The evolution of this approach is discussed in this paper.

Surgical resection of large and giant petroclival meningiomas via a modified anterior transpetrous approach

The authors describe a modified anterior transpetrous approach (ATPA) for the surgical resection of 21 cases of petroclival meningiomas (PCMs). Briefly, a curved periauricular skin incision was used. The cerebellar tentorium and the dura on the petrous apex were coagulated and incised to expose the petrous apex bone fully. The drilling of the petrous apex bone was performed subdurally and began internally from the trigeminal impression, not exceeding 1.5 cm laterally, not exceeding 6 mm from the posterior edge of the petrous ridge, and not exceeding 8 mm in depth from the surface of the petrous bone. The tumors were removed totally in 12 (57.1 %) cases, subtotally in 8 (38.1 %) cases, and partially in 1 (4.8 %) case. The transient neurological deficit includes mild oculomotor nerve palsy in three cases, abducens nerve palsy in six cases, language disorder in three cases, and mild hemiplegia in two cases. Facial numbness became worse postoperatively in six patients, and only two patients improved at 6 months after surgery. No death occurred in this series. The modified ATPA is an efficient treatment alterative for large or giant PCMs located at the medial and superior internal acoustic meatus with relatively low risk of complications.

Subtemporal transtentorial petrosalapex approach for giant petroclival meningiomas: analyzation and evaluation of the clinical application

With the advent of microsurgery and surgical techniques, along with the improvement in neuroimaging techniques and the microanatomy in cadaver study, improvement in terms of surgical morbidity and mortality has been remarkable; however, controversy still exists regarding the optimal surgical strategies for giant petroclival meningiomas (GPMs). We report a study of clinical and radiological features as well as the surgical findings and outcomes for patients with GPM treated at our institution over the past 6 years. During a 6-year period (April 2004 to March 2010), 16 patients with GPM underwent surgery by subtemporal transtentorial petrosal apex approach during which electrophysiological monitoring of cranial nerves and brainstem function were reviewed. There were nine females and seven males with a mean age of 56.9 years (range from 32 to 78 years). The most frequent clinical manifestations were headache (93.7%) and dizziness (93.7%). Regions and directions of tumor extension include clivus, parasellar, and cavernous sinus, as well as compression of brainstem, and so on. The trochlear nerve was totally wrapped in nine cases (56.2%). The postoperative Karnofsky Performance Scale (KPS) score was 76.3 ± 13.1. Mean maximum diameter of the tumors on magnetic resonance imaging was 5.23 cm (range, 4.5 to 6.2 cm). Subtemporal transtentorial petrosalapex approach was performed in all 16 cases. Gross total resection was achieved in 14 cases (87.5%) and subtotal resection in 2 cases (12.5%) with no resultant mortality. Follow-up data were available for all 16 patients, with a mean follow-up period of 28.8 months (range from 4 to 69 months), of which 11 (68.75%) lived a normal life (KPS, 80-100). Our suggestion is that GPM could be completely resected by subtemporal transtentorial petrosalapex approach. The surgical strategy of GPM should be focused on survival and postoperative quality of life. Microneurosurgical technique plays a key role in tumor resection and preservation of nerve function. Intraoperative electrophysiological monitoring also contributes dramatically to the preservation of the nerve function. Complete resection of the tumor should be attempted at the first operation. Any remnant is treated by radiosurgery.

Posterior fossa meningioma "our experience" in 64 cases

Background:

Posterior fossa meningiomas are 20% of all intracranial meningiomas. These are slow-growing tumors thus become large before presentation. Microsurgical resection is the treatment of choice for the majority of these lesions, but variable locations, large size at diagnosis, frequent encroachment of neural and vascular structures, and their potentially invasive behavior are some of the features of these tumors that make their resection challenging.

Materials and Methods:

We studied 64 cases of posterior fossa meningioma operated in last 6 years, and analysed the technical difficulties encountered during excision of these tumors. Postoperative complications and outcomes of these patients were also analysed.

Results:

Gross total excision was achieved in 72% cases. Partial excision or subtotal excision was more in petroclival, jugular foramen with extra cranial extension, tentorial with intrasinus extension and ventral foramen magnum. Postoperative complication in form of new or aggravation of existing neurological deficit was found in 33% cases and CSF leak in 12.5% cases. We encountered the recurrence of total 10 cases (16%) over mean follow-up of 4 years. Most of the recurrent cases were seen in petroclival and tentorial subgroups with partial or subtotal excision.

Conclusion:

Posterior fossa meningiomas are difficult to excise due to close relation to cranial nerves and vessels. Use of microscope, CUSA, intraoperative nerve monitor help in removal and preserving surrounding important anatomical structures. Although neurological deterioration is common postoperatively, recovery does occur completely after total removal thus increasing the recurrence free period and improving the outcome.

A comparative anatomic study of a modified temporal-occipital transtentorial transpetrosal-ridge approach and a transpetrosal presigmoid approach

OBJECTIVE

To evaluate the anatomic features of a modified temporal-occipital transtentorial transpetrosal-ridge approach versus the conventional approach for surgery of petroclival tumors.

METHODS

The conventional transpetrosal presigmoid approach or the modified temporal-occipital transtentorial transpetrosal-ridge approach was performed on different sides of the heads from 10 adult Chinese cadavers to compare incision site, exposure area, and operating space.

RESULTS

In the modified approach, only medial and median parts of the petrous ridge were removed. No significant differences in maximal visual angle and operative depth were found between the two approaches (P > 0.05). The modified approach required a much smaller bone window compared with the presigmoid approach. The exposure in the middle of the ventral brainstem in the modified approach was much greater than in the presigmoid approach. The angle required for exposure of the temporal lobe via the ventral medulla oblongata in the modified approach was much smaller than in the presigmoid approach (P < 0.05).

CONCLUSIONS

The modified temporal-occipital transtentorial transpetrosal-ridge approach is a feasible surgical approach to remove petroclival tumors.

Surgery for petroclival meningiomas: a comprehensive review of outcomes in the skull base surgery era

Skull base surgery has evolved to a point that its focus is now shifting to outcome analysis. To do so for petroclival meningiomas is difficult. The rarity of the tumor, different treatment philosophies, and variations in reporting complicate the outcome analysis. With this limitation in mind, we analyzed the literature on this disease and report the combined outcomes in a unified fashion in hopes that it will serve as a starting point for further prospective analysis. Data was extracted from all available reports on MEDLINE/PubMed published in English. All studies were retrospective and uncontrolled. The majority of studies represent the experience of a single surgeon at a single institution. Of the 19 studies with detailed demographic and outcome data, no data met criteria for meta-analysis. A total of 1000 patients were reported. The mean age of the patients was 50 years. The male to female ratio is 1:3. GTR (gross total resection) was reported in 49% of patients. Thirty-four percent of patients experienced some neurological deficit in the early postoperative period (<3 months). The most common morbidities reported were cranial nerve deficits (34.4% [range: 20 to 79%]) with facial nerve injury accounting for 19%, followed by motor deficits (14%), infection rates (1.6%), CSF leaks (5%), hemorrhage (1.2%), and hydrocephalus (1%). Death within 1 year of surgery was reported for 1.4% of patients. Once considered untreatable, petroclival meningiomas can now be approached relatively safely. There, however, still remains an ∼34% morbidity with the most common being cranial nerve. Despite this, >75% of patients return to independence at 1 year, many of which will resume employment. The nature of this study limits the conclusions that can be drawn; however, it provides some generalizations that may help guide patient questions regarding treatment outcomes.

Meningiomas with vertebrobasilar artery encasement: review of 17 cases

Seventeen patients with petroelival and foramen magnum meningiomas encasing the vertebral or basilar arteries and their branches were surgically excised over a 3-year period. All six cases with vertebral artery encasement were totally excised. One vertebral artery was occluded, one was repaired, and one was replaced with a vein graft. None of the patients had a permanent major neurologic deficit. In one patient with vertebral and basilar artery encasement, a hypoplastic vertebral artery was occluded and the tumor was totally excised. She had a transient worsening of hemiparesis, presumably due to the dissection of tumor from the brainstem. Among the ten patients with encasement of the basilar artery and branches, injury to the basilar artery occurred in two patients, both were repaired. Injuries to one superior cerebellar artery, one anterior inferior cerebellar artery, and one perforating vessel could not be repaired. Three patients sustained major neurologic deficits, but only in two did this result in permanent functional deterioration. Three of the ten patients had a gross total resection, five had subtotal resection (90% or more of tumor volume), and two had resection of 70% of the tumor volume. Eight patients had improvement in their Karnofsky scores. None showed recurrence or regrowth on follow-up ranging from 2 to 6 years. Greater difficulty with dissection was experienced in previously operated patients, and in patients who did not have an arachnoid plane between the brainstem and the tumor. Magnetic resonance imaging was the most useful preoperative test. It is concluded that meningiomas with vertebrobasilar artery encasement can be removed successfully with modern skull base surgery techniques. The surgeon needs to exercise caution and judgment in deciding how far the removal of these lesions should be pursued.

Posterior fossa meningioma: surgical strategy

Posterior fossa meningioma is the second most common tumor in the cerebellopontine angle. It has a higher rate of postoperative morbidity and mortality compared to acoustic neuroma. Forty posterior fossa meningioma patients managed in our centers were reviewed. Thirty-nine patients were managed surgically with 42 surgical procedures. The approaches used were the translabyrinthine approach in 18 patients (43%), the modified transcochlear in 11 cases (26%), the petro-occipital transsigmoid in 5 cases (12%), the suboccipital in 4 cases (10%), the petro-occipital trassigmoid transcervical in 2 cases (5%), the petro-occipital transsigmoid transtentorial in 1 case (2%), and a subtemporal transtentorial for another case (2%). Facial nerve anatomical integrity was preserved in 87% of procedures but was interrupted in 5 cases, with 4 of the latter subsequently repaired. Total tumor removal was accomplished in 38 cases. A second-stage total tumor removal is planned for the remaining case. There was only one case of perioperative death and no cases of radiological recurrence so far.

Stereotactic approach to skull-base lesions

With improved knowledge of the anatomy and increased collaboration between the neurosurgeon and the otolaryngologist, successful surgical resection of skull-based tumors is being achieved with reduced mortality and morbidity. In spite of this, there remains a group of patients in whom an alternate surgical approach of stereotaxis may be indicated. This group of patients includes those in whom only biopsy is required, or those in whom brachytherapy using high-intensity (125)I is planned because the patients' general condition is not good enough to undergo open surgical resection of the tumor or the tumor is unresectable or the patient refuses open surgery. This article presents a preliminary report on stereotactic approach to skull base lesions with special emphasis on the technique.

Presigmoid sinus approach to petroclival meningiomas

Between August 1987 and May 1989 five patients with petroclival meningiomas were operated on at the Neurosurgical Clinic of the Krankenhaus Nordstadt. Hannover, Germany, using an original combined supra- and infratentorial presigmoid sinus approach. There were two men and three women, ranging in age from 34 to 61 years (mean, 48 years; median, 46 years). Follow-up ranged between 1 and 22 months. There was no death. Postoperatively, two patients had no useful hearing, one had a permanent facial palsy (the facial nerve had to be sacrificed intraoperatively due to its involvement with tumor), one had a permanent abducens palsy (the VI nerve was involved with tumor and had to be cut). Temporary lower (IX to XII) cranial nerve palsy was observed in all the patients; temporary VI, in two patients; temporary VII, in two patients, temporary hemiparesis, in one patient, temporary gait ataxia, in three patients; and persistent gait ataxia, in one patient. All patients had total tumor removal as assessed at surgery and with postoperative enhanced computed tomography. Four patients were independent and able to carry on normal activity, and one patient was independent at home but not outside due to severe ataxia 4 months after the operation. The presigmoid sinus avenue to the petroclival region shortens the distance to the clivus, permits a multiangled exposure of this difficult surgical area, minimizes the amount of temporal lobe retraction, preserves the integrity of the transverse sinus, and allows for better preservation of the neurovascular structures. These factors translate into a high percentage of total tumor removal and a low incidence of permanent morbidity.

Combined approach for lesions involving the cerebellopontine angle and skull base: experience with 30 cases

This article presents a series of 30 patients who underwent a combination of the subtemporal and posterior fossa approaches for exposure of lesions in the clivus or medial petrous region. This combined supra- and infratentorial approach is divided into three variations with progressively greater petrous bone resection to increase exposure of the clivus and medial petrous region. The approach has been divided into petrous bone resection with preservation of hearing (retrolabyrinthine), greater petrous bone resection with sacrifice of hearing (translabyrinthine), and finally maximum petrous drilling with sacrifice of hearing along with transposition of the facial nerve (transcochlear). Ninety-three percent of the cases returned to their premorbid occupations.