Premeatal and retromeatal cerebellopontine angle meningioma. Two distinct clinical entities

Surgical management of large cerebellopontine angle meningiomas: long-term results of a less aggressive resection strategy

OBJECTIVE

Cerebellopontine angle (CPA) meningiomas present many surgical challenges depending on their volume, site of dural attachment, and connection to surrounding neurovascular structures. Assuming that systematic radical resection of large CPA meningiomas carries a high risk of permanent morbidity, the authors adopted an alternative strategy of optimal resection followed by radiosurgery or careful observation of the residual tumor and assessed the efficiency and safety of this approach to meningioma treatment management.

METHODS

This single-center retrospective cohort study included 50 consecutive patients who underwent surgery for meningioma between January 2003 and February 2020.

RESULTS

The most common main dural attachments of the meningiomas were posterior (42%) and superior (26%) to the internal auditory meatus. The suboccipital retrosigmoid route was the most routinely used (92%). At the last follow-up examination, 93% of the patients with normal preoperative facial nerve (FN) function retained good House-Brackmann (HB) grades of I and II, whereas 3 patients (7%) displayed intermediate HB grade III FN function. Hearing preservation was achieved in 86% of the patients who presented with preoperative serviceable hearing, and recovery after surgery was achieved in 19% of the patients experiencing preoperative hearing loss. In order to preserve all cranial nerve function, gross-total resection was obtained in 26% of patients. Of the 35 patients who had undergone subtotal resection, 20 (57%) had been allocated into a wait-and-rescan treatment approach and 15 (43%) underwent upfront Gamma Knife surgery (GKS). The mean postoperative tumor volume was 1.20 cm3 in the upfront GKS group and 0.73 cm3 in the wait-and-rescan group (p = 0.08). Tumor control was achieved in 87% and 55% of cases (p < 0.001), with a mean follow-up of 85 and 69 months in the GKS and wait-and-rescan groups, respectively. The 1-, 5-, and 7-year tumor progression-free survival rates were 100%, 100%, and 89% in the GKS group and 95%, 59%, and 47% in the wait-and-rescan group, respectively (p < 0.001).

CONCLUSIONS

Optimal nonradical resection of large CPA meningiomas provides favorable long-term tumor control and functional preservation. Adjuvant GKS does not carry additional morbidity and appears to be an efficient adjuvant treatment.

Unexpected recovery from complete deafness to normal hearing post surgical excision of a cerebellopontine angle meningioma: A case report

Background

Cerebellopontine angle (CPA) meningioma presents a significant management challenge due to its intricate relationship with the brainstem neurovascular bundles. The emphasis in the past has been on facial nerve preservation, but the current management standard is hearing preservation in patients with serviceable hearing; however, hearing restoration after complete loss is rare. We report an elderly man who had restoration of hearing in the right ear after complete loss following tumor resection through the retrosigmoid route.

Case Description

A 73-year-old male patient presented with progressive hearing impairment in the right ear, culminating in hearing loss for about 2 months (the American Academy of Otolaryngology-Head and Neck Surgery [AAO-HNS] class D). He also had mild cerebellar symptoms, but other cranial nerves and long tracts were normal. Brain magnetic resonance imaging confirmed a right CPA meningioma, and he had tumor resection through the retrosigmoid route using meticulous microsurgical technique with vestibulocochlear nerve preservation, facial nerve monitoring, and intraoperative video angiography. He had restoration of hearing on follow-up (the American Academy of Otolaryngology-Head and Neck Surgery class A). Histology confirmed World Health Organization central nervous system grade 1 meningioma.

Conclusion

This case illustrates that hearing restoration is possible after complete loss in patients with CPA meningioma. We advocate hearing preservation surgery even in patients with non-serviceable hearing, as the chance of hearing recovery is possible.

Posterior Petrous Meningiomas: Surgical Classification and Postoperative Outcomes in a Case Series of 130 Patients Operated via the Retrosigmoid Approach

OBJECTIVE

A standardized definition and classification of primary posterior petrous meningiomas (PPMs) is lacking, with consequent challenges in comparing different case series. This study aimed to provide an anatomical description and classification of PPMs analyzing a homogeneous series of patients operated via the retrosigmoid approach.

METHODS

PPMs originate laterally to the petro-occipital fissure within the venous ring composed of the superior petrosal, sigmoid, inferior petrosal, and cavernous sinuses. We proposed a classification based on tumor site of origin, direction of growth relative to the internal acoustic meatus, and cranial nerves' displacement. Four types of PPMs were defined: retromeatal (type A), meatal (type B), premeatal (type C), and broad-based (type D). We performed a retrospective analysis of 130 consecutive patients with PPMs who underwent surgery as first-line treatment.

RESULTS

The PPM classification predicted clinical presentation, postoperative morbidity, and resection rates. Headache, hydrocephalus, and cerebellar deficits were more common in type A (59.0%, 37.7%, 49.2%) and type D (66.7%, 66.7%, 33.3%). Hypoacusia/anacusia was more common in type B (87.5%), while trigeminal hypoesthesia/anesthesia was more common in type C (85.0%). After surgery, patients with type A and D PPMs were at higher risk to develop cerebellar deficits (11.5%-22.2%), whereas patients with type B and C PPMs presented with hypoacusia/anacusia (12.5%) and trigeminal deficits (10.0%), respectively. The near-total resection rate was higher in type A (91.8%), followed by types B (82.5%), C (80.0%), and D (77.8%) PPMs.

CONCLUSIONS

The PPM surgical classification has an operative and prognostic relevance. In expert hands, the retrosigmoid approach represents a safe and effective approach to remove PPMs.

Microsurgical transcranial approaches to the posterior surface of petrosal portion of the temporal bone: quantitative analysis of surgical volumes and exposed areas

Different microsurgical transcranial approaches (MTAs) have been described to expose the posterior surface of the petrous bone (PPB). A quantitative, anatomical comparison of the most used MTAs, for specific areas of the PPB, is not available. Anatomical dissections were performed on five formalin-fixed, latex-injected cadaver heads (10 sides). Six MTAs were analyzed: Kawase approach (KWA), retrosigmoid approach (RSA), retrosigmoid approach with suprameatal extension (RSAS), retrolabyrinthine approach (RLA), translabyrinthine approach (TLA), and transcochlear approach (TCA). Surgical volumes and exposed areas of each approach were quantified with a dedicated neuronavigation system (ApproachViewer, part of GTx-Eyes II, University Health Network, Toronto, Canada) and adjuvant software (ITK-SNAP and Autodesk Meshmixer 3.5). Areas and volumes were compared using linear mixed models. TCA provided the best exposure of Trautmann's triangle and the retromeatal, suprameatal, meatal, and premeatal regions. RSAs provided the best exposure of the inframeatal region, with RSAS gaining significant exposure of the suprameatal region. KWA had the highest surgical volume, and RLA the lowest. Transpetrosal approaches offer the widest exposure of PPB proportionally to their invasiveness. Retrosigmoid approaches, which get to the studied region through a postero-lateral path, are paramount for the exposure of the inframeatal and suprameatal region and, given the adequate exposure of the remaining PPB, represent an effective approach for the cerebellopontine angle (CPA). These anatomical findings must be considered with approach-related morbidity and the pathological features in order to choose the most appropriate approach in clinical practice.

The otologic approach in the management of posterior petrous surface meningiomas

PURPOSE

Report our experience in the management of posterior petrous surface meningiomas (PPSMs), and identify features that affect hearing, facial nerve (FN) function, and control of the disease.

METHODS

Retrospective case series of 131 patients surgically managed for PPSMs. FN status, hearing and tumour radicality were assessed and compared between patients with tumours of different locations (Desgeorges classification) and internal auditory canal involvement (IAC).

RESULTS

At the time of surgery 74.8% of patients had a hearing loss. Hearing was mostly unserviceable in tumors attached to the meatus. Pure tone audiometry did not correlate to IAC extension, while speech discrimination scores were statistically worse when the tumor occupied the IAC (unpaired t test, p = 0.0152). Similarly, extrameatal tumors undergoing removal by otic preserving techniques maintained postoperative hearing, whereas hearing worsened significantly in tumors involving the IAC (paired t test, p = 0.048). The FN was affected preoperatively in 11.4% of cases. Postoperative FN palsy was significantly correlated to the IAC involvement (Fisher's exact test, p = 0.0013), while it was not correlated to tumor size. According to the Desgeorges classification, a postoperative FN palsy complicated the majority of anteriorly extending tumors and, two-fifths of meatus centred tumors. 75% of posterior located tumors had a postoperative FN grade I HB.

CONCLUSIONS

Since the involvement of the IAC by the tumor affects both hearing and FN function, the IAC is of primary importance in PPSMs and should be studied and addressed as much as the tumor location in the CPA.

[Giant petrosal meningioma invading the fourth ventricle: total removal of a recurrent tumor after eighteen years. Neurosurgical nuances. Case report and literature review]

The authors present a patient and neurosurgical nuances of total resection of recurrent meningioma of posterior surface of petrous bone 65´35´30 mm. The tumor captured two critical zones of posterior cranial fossa with unusual frontal growth and spread from the surface of petrous bone to the fourth ventricle. The neoplasm filled the ventricle without lesion of ependyma. Extensive fibrous meningioma of posterior surface of petrous bone was totally excised 18 years ago. MRI was annually carried out for 5 years. Surgical nuances that ensured total extraction of tumor without cytoreduction were as follows: 1) en-bloc resection of tumor from the fourth ventricle due to smooth surface of tumor and minimum number of adhesions with cerebellum; MR-confirmed CSF strip between the tumor edges and walls of the ventricle; no signs of hydrocephalus in subtotal ventricular tamponade; 2) unusual frontal tumor growth under 45º required appropriate angular traction of tumor with minimal rotation; 3) traction was followed by sequential appearance of 3 segments of tumor: petrous, apertural and ventricular; 4) topography of the area of lateral eversion of the fourth ventricle was established by identifying the narrowing (constriction) of tumor; 5) in extracting the tumor from the fourth ventricle, we performed minimal rotation to avoid damage to ventricular walls and lateral aperture due to difference between the larger and smaller diameters (by 6 mm) of ovoid ventricular segment of tumor; 6) no CSF leakage following appearance of ventricular segment (tumor enlargement) indicated integrity of ependyma of the fourth ventricle. Histological examination confirmed fibrous meningioma. Fast and complete regression of focal symptoms was observed after surgery. A 3-year follow-up after surgery revealed no signs of tumor recurrence.

Natural history of intracranial meningiomas

We know that the extent of resection is the greatest predictor of long-term survival. However, the potential tradeoff for gross total resection in difficult locations is diminished quality of life. Benign subtotally resected or small incidentally discovered meningiomas may be followed clinically especially in the elderly. In addition, radiosurgery plays a role in the treatment of meningiomas as a primary treatment modality, or as a salvage therapy. Decisions regarding management should be made with an understanding of the natural history and rate of growth. In this chapter we review the known meningioma epidemiology as well as the growth patterns of meningiomas based upon location.

Hearing preservation after Gamma Knife radiosurgery for cerebellopontine angle meningiomas

OBJECTIVE

The objective of this study was to assess hearing function after Gamma Knife treatment of cerebellopontine angle (CPA) meningiomas and assess factors affecting hearing outcome. Additionally, the authors opted to compare these results with those after Gamma Knife treatment of vestibular schwannomas (VSs), because most of the information on hearing outcome after stereotactic radiosurgery (SRS) comes from reports on VS treatment. Hearing preservation, to the best of the authors’ knowledge, has never been separately addressed in studies involving Gamma Knife radiosurgery (GKRS) for CPA meningiomas.

METHODS

This study included all patients who underwent a single session of GKRS between 2002 and 2014. The patients were divided into two groups. Group A included 66 patients with CPA meningiomas with serviceable hearing and tumor extension into the region centered on the internal auditory meatus. Group B included 144 patients with VSs with serviceable hearing. All patients had serviceable hearing before treatment (Gardner-Robertson [GR] Grades I and II). The median prescription dose was 12 Gy (range 10–12 Gy) in both groups. The median follow-up of groups A and B was 42 months (range 6–149 months) and 49 months (range 6–149 months), respectively.

RESULTS

At the last follow-up, the tumor control rate was 97% and 94% in groups A and B, respectively. Hearing preservation was defined as maintained serviceable hearing according to GR hearing score. The hearing preservation rate was 98% and 66% and the 7-year actuarial serviceable hearing preservation rate was 75% and 56%, respectively, between both groups. In group A, the median maximum cochlear dose in the patients with stable and worsened hearing grade was 6.3 Gy and 5.5 Gy, respectively. In group B, factors affecting hearing preservation were cochlear dose ≤ 7 Gy, follow-up duration, and tumor control. The only determinant of hearing preservation between both groups was tumor type.

CONCLUSIONS

GKRS for CPA meningiomas provides excellent hearing preservation in addition to high tumor control rate. Hearing outcome is better with CPA meningiomas than with VSs. Further long-term prospective studies on determinants of hearing outcome after GKRS for CPA meningiomas should be conducted.

Posterior fossa meningioma with invasion of the internal acoustic canal

BACKGROUND

To evaluate the significance for outcome of meningioma invasion into the internal auditory canal (IAC) in posterior fossa meningiomas.

METHODS

From April 2005 to September 2015, 174 posterior fossa meningiomas have been surgically treated in our Institution. Careful analysis of preoperative MRI depicted in 63 cases (36%) meningioma invasion into the IAC. A retrospective analysis was done of clinical and radiological presentation, surgical findings, outcome, and relevant prognostic factors in order to stratify the risk of complication and evaluate the surgical outcome.

RESULTS

Gross total resection was achieved in 67% of patients. There was no mortality. CSF leak occurred in 5%. Postoperative moderately severe (HB 4) and severe dysfunction (HB 5) of the facial nerve was observed in 5% of patients. In 17 patients (27%), IAC was opened. Deterioration of facial function occurred in 24% of patients, hearing loss in 12%, and CSF leak in 6%. In 46 patients (73%), IAC was not opened. Deterioration of facial function occurred in 43% of patients, hearing loss in 13%, and CSF leak in 4%. Opening the IAC, a GTR was achieved in 82% while, without opening, in 61% of patients.

CONCLUSIONS

Meningiomas of the posterior fossa may in one-third of the cases invade the IAC. Opening of the IAC in these cases was a crucial step for increasing the GTR. Despite the minimal increased risk of transient CSF leak, IAC opening was not associated with an increased risk of facial palsy or hearing loss in comparison to non-opening the IAC.

Petrous Face Meningiomas: Classification, Clinical Syndromes, and Surgical Outcomes

BACKGROUND

Petrous face meningiomas (PFMs) are challenging tumors because of their proximity to the cranial nerves, brainstem, and critical vasculature. The objective of this study is to present surgical outcomes and support an anatomic classification for PFM based on clinical presentation.

METHODS

A retrospective chart review was performed, and 51 PFMs were identified. Tumors were classified by location along the petrous face into anterior, middle, and posterior. Presentation and outcomes were analyzed with logistic regression.

RESULTS

The median follow-up was 31.6 months. Tumors were World Health Organization grade I (n = 50), with 1 World Health Organization grade II tumor. Location was anterior (22%), middle (14%), posterior (53%), and overlapping (12%). Median tumor diameter was 3.0 cm (range, 0.8-6.2 cm). Anterior location was associated with facial pain/numbness on presentation (P < 0.0001), middle location with hearing loss/vestibular dysfunction (P = 0.0035), and posterior with hydrocephalus (P = 0.0190), headache (P = 0.0039), and vertigo (P = 0.0265). Extent of resection was gross total (63%), near total (14%), and subtotal (25%). The observed radiographic recurrence rate was 15%. Mean progression-free survival after diagnosis was 9.1 years with 2-year, 5-year, and 10-year progression-free survival of 91.8%, 78.6%, and 62.9%, respectively. The complication rate was 27%. Age, location, and approach were not associated with complications.

CONCLUSIONS

PFMs present with distinct clinical syndromes based on their location along the petrous face: anterior with trigeminal symptoms, middle with auditory/vestibular symptoms, and posterior with symptoms of mass effect/hydrocephalous. Surgical resection is associated with excellent long-term survival and a low rate of recurrence, which can be managed with radiotherapy.

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.

Trigeminocardiac reflex during cerebellopontine angle surgery: anatomical location as a new risk factor

ABSTRACT 

Aim: Trigeminocardicac reflex (TCR), a brainstem reflex, can be manifested in almost all types of surgery in the head and neck region. Patients & methods: Retrospective review of 125 patients operated on cerebellopontine angle (CPA) tumors according to strict inclusion/exclusion criteria. Results: A total of 14 out of 125 patients showed TCR during CPA tumor operation. In total, 29% of those patients presented with a meningioma located exclusively premeatal, but not retromeatal in the CPA. There was significant relationship between meningiomas subgroups and TCR (Barnard test; p < 0.05). Conclusion: Anatomical location may represent an important, but not yet described risk factor for the TCR having therefore an important role in the understanding of the TCR.

Gamma Knife Radiosurgery for Cerebellopontine Angle Meningiomas

BACKGROUND:

Resection of cerebellopontine angle (CPA) meningiomas may result in significant neurological morbidity. Radiosurgery offers a minimally invasive alternative to surgery.

OBJECTIVE:

To evaluate, in a multicenter cohort study, the outcomes of patients harboring CPA meningiomas who underwent Gamma Knife radiosurgery (GKRS).

METHODS:

From 7 institutions participating in the North American Gamma Knife Consortium, 177 patients with benign CPA meningiomas treated with GKRS and at least 6 months radiologic follow-up were included for analysis. The mean age was 59 years and 84% were female. Dizziness or imbalance (48%) and cranial nerve (CN) VIII dysfunction (45%) were the most common presenting symptoms. The median tumor volume and prescription dose were 3.6 cc and 13 Gy, respectively. The mean radiologic and clinical follow-up durations were 47 and 46 months, respectively. Multivariate regression analyses were performed to identify the predictors of tumor progression and neurological deterioration.

RESULTS:

The actuarial rates of progression-free survival at 5 and 10 years were 93% and 77%, respectively. Male sex (P = .014), prior fractionated radiation therapy (P = .010), and ataxia at presentation (P = .002) were independent predictors of tumor progression. Symptomatic adverse radiation effects and permanent neurological deterioration were observed in 1.1% and 9% of patients, respectively. Facial spasms at presentation (P = .007) and lower maximal dose (P = .011) were independently associated with neurological deterioration.

CONCLUSION:

GKRS is an effective therapy for CPA meningiomas. Depending on the patient and tumor characteristics, radiosurgery can be an adjuvant treatment to initial surgical resection or a standalone procedure that obviates the need for resection in most patients.

Stereotactic radiosurgery for cerebellopontine angle meningiomas

Object

To assess the long-term outcomes of stereotactic radiosurgery (SRS) for cerebellopontine angle (CPA) meningiomas, the authors retrospectively reviewed data from a 20-year experience. They evaluated progression-free survival as well as improvement, stabilization, or deterioration in clinical symptoms.

Methods

Seventy-four patients with CPA meningiomas underwent SRS involving various Gamma Knife technologies between 1990 and 2010. The most common presenting symptoms were dizziness or disequilibrium, hearing loss, facial sensory dysfunction, and headache. The median tumor volume was 3.0 cm3 (range 0.3–17.1 cm3), and the median radiation dose to the tumor margin was 13 Gy (range 11–16 Gy). The median follow-up period was 40 months (range 4–147 months).

Results

At last imaging follow-up, the tumor volume had decreased in 46 patients (62%), remained stable in 26 patients (35%), and increased in 2 patients (3%). The progression-free survival after SRS was 98% at 1 year, 98% at 3 years, and 95% at 5 years. At the last clinical follow-up, 23 patients (31%) showed neurological improvement, 43 patients (58%) showed no change in symptoms or signs, and 8 patients (11%) had worsening symptoms or signs. The neurological improvement rate after SRS was 16% at 1 year, 31% at 3 years, and 40% at 5 years. The post-SRS deterioration rate was 5% at 1 year, 10% at 3 years, and 16% at 5 years. A multivariate analysis demonstrated that trigeminal neuralgia was the symptom most likely to worsen after SRS (HR 0.08, 95% CI 0.02–0.31; p = 0.001). Asymptomatic peritumoral edema occurred in 4 patients (5%) after SRS, and symptomatic adverse radiation effects developed in 7 patients (9%).

Conclusions

Stereotactic radiosurgery for CPA meningiomas provided a high tumor control rate and relatively low risk of ARE. Tumor compression of the trigeminal nerve by a CPA meningioma resulted in an increased rate of facial pain worsening in this patient experience.

Trigeminal neuralgia in a patient with Marfan syndrome: case report

Marfan syndrome can demonstrate tortuous and elongated intracranial arteries. However, these arteries rarely cause neurovascular compression resulting in hemifacial spasm or trigeminal neuralgia. The authors report a 33-year-old woman who was diagnosed as Marfan syndrome, suffered from trigeminal neuralgia. Magnetic resonance (MR) angiography showed tortuous and elongated left vertebral artery (VA). The coronal section of three dimensional (3D) MR cisternography with contrast enhancement showed that the left trigeminal nerve was compressed from underneath by the tortuous and elongated left VA. After successful surgery of microvascular decompression, the patient’s symptom resolved and no recurrence was encountered. Neurosurgeons should not only be aware of hemifacial spasm but also of trigeminal neuralgia caused by elongated vessels in a patient with Marfan syndrome, although it is an extremely rare condition. In addition, offending vessel is not atherosclerotic in younger patients unlike usual cases of trigeminal neuralgia. Thus, microvascular decompression can be easier than usual cases. Care should be taken to prevent arterial dissection during transposition by using some technical tips.

A single spinal lesion arising from an intradural meningioma contiguous with an extradural lymphoma

The authors describe here a unique case of contiguous, synchronous meningioma and lymphoma in the spinal column. Both tumors were present at the same vertebral level, one intradural and the other extradural. A patient presented with bilateral leg pain, acute weakness, and sensory loss in the lower extremities. Magnetic resonance imaging revealed an intradural mass at T6-7 with ambiguous boundaries relative to the thecal sac and compressing the spinal cord. The patient underwent resection of the epidural and intradural mass at T6-7. Histopathology revealed the epidural specimen to be a double-hit B-cell lymphoma and the intradural mass to be a transitional meningioma. Postoperatively, the patient did well, with an immediate return of strength and sensation. A postoperative MR image showed complete resection of the intradural mass. The authors suggest that biopsy may be prudent in patients with known systemic lymphoma presenting with a spinal lesion that has unclear boundaries relative to the thecal sac prior to commencing radiation and chemotherapy.

Further data favouring hormonal dependency of cerebral meningiomas: evidence from a patient treated with cabergoline

OBJECTIVE

To explore the role of cabergoline, a dopamine agonist, in the progression of meningiomas.

DESIGN

Case report.

SETTING

Teaching hospital in Barcelona, Spain (Gynecology, Obstetrics and Neonatology Clinical Institute, Hospital Clínic).

PATIENT(S)

Women with a history of meningioma underwent surgery via right pterional craniotomy. During the follow-up, at 18 months after the operation the patient developed a progressive hyperprolactinemia with amenorrhea and galactorrhea. An MR examination revealed a recurrence of the neoplasm.

INTERVENTION(S)

Cabergoline treatment.

MAIN OUTCOME MEASURE(S)

Progression of meningioma.

RESULT(S)

Long-standing cabergoline treatment in this patient with meningioma relapse early after surgery and subsequent hyperprolactinemia resulted in absence of progression of the neoplasm many years after the dopamine agonist initiation.

CONCLUSION(S)

These data suggest that cabergoline, a dopamine agonist, had an antiproliferative effect on the growth of meningiomas. Thus, one can hypothesise that the proliferation of cerebral meningiomas may be under dopaminergic control and that dopamine agonists such cabergoline may have a potential role in the medical treatment of patients with meningiomas.

Petroclival meningiomas: study on outcomes, complications and recurrence rates

OBJECT

Petroclival meningiomas are notoriously difficult lesions to manage surgically, given the critical neurovascular structures that are intimately associated with the tumors. In this paper, the authors' aim was to review their series of patients with petroclival meningiomas who underwent surgical treatment; emphasis was placed on evaluating modes of presentation, postoperative neurological outcome, complications, and recurrence rates.

METHODS

Fifty patients underwent surgical treatment for petroclival meningiomas. The majority of the patients were women (72%). The authors retrospectively reviewed the patients' medical records, imaging studies, and pathology reports to analyze presentation, surgical approach, neurological outcomes, complications, and recurrence rates.

RESULTS

Headache was the most common presentation (58%). The most commonly used approach was the transpetrous approach (in 16 patients), followed by the orbitozygomatic approach (in 13). Gross-total resection was performed in 14 patients (28%), and in the remaining patients there was residual tumor (72%). Eighteen patients with tumor remnants were treated with Gamma Knife surgery. New postoperative cranial neuropathies were noted in 22 patients (44%). The most common cranial nerve (CN) deficit following surgery was CN III dysfunction (in 11 patients) and facial weakness (in 10). In 9 patients, the CN dysfunction was transient (41%), and 7 patients had permanent dysfunction (32%). Eight patients developed hydrocephalus and all required placement of a ventriculoperitoneal shunt. A CSF leak was noted in only 2 patients (4%), and wound dehiscence was noted in 1. The CSF leaks and the wound dehiscence occurred in patients who were undergoing reoperations. Adequate radiographic follow-up (minimum 6 months) was available for 31 patients (62%). The mean follow-up was 22.1 months. In 6 patients, tumor progression or recurrences were noted. The median time to recurrence was 84 months. At the time of discharge from the hospital, 92% of the patients had good outcomes (Glasgow Outcome Scale Scores 4 and 5). Three patients died of causes not directly related to the surgery.

CONCLUSIONS

Petroclival meningiomas still pose a formidable challenge to neurosurgeons. In their series, the authors used multiple skull base approaches and careful microneurosurgical technique to achieve a good functional outcome (Glasgow Outcome Scale Score 4 or 5) in 92% of patients, although the extent of gross-total resection was only 28%. The authors' primary surgical goal was to achieve maximal tumor resection while maintaining or improving neurological function. The authors favor the treatment of residual tumor or recurrent tumor with stereotactic radiosurgery.

Outcome after microsurgery for meningiomas involving the internal auditory canal

BACKGROUND

The subset of patients suffering from meningiomas truly originating in or extending into the internal auditory canal is not well described in the literature.

OBJECTIVE

To evaluate postoperative facial motor and hearing outcomes in patients undergoing resection of meningiomas originating in or extending into the internal auditory canal.

METHODS

Chart reviews were done of 19 consecutive patients undergoing surgery for meningiomas originating in or extending into the internal auditory canal at the Mayo Clinic, Rochester, with emphasis on clinical exam and audiometry.

RESULTS

Median follow-up for the entire group was 29 months. Seventy-four percent of patients had stable facial nerve function. One patient experienced improvement. Postoperative cochlear nerve function was unchanged in 74% of patients and worsened in 21% of patients. One patient with a sudden preoperative hearing loss improved to full hearing at 3 months.

CONCLUSION

Every attempt should be made to preserve hearing and facial motor function in surgical removal of posterior fossa meningiomas that originate in or extend into the internal auditory canal. Normal or nearly normal facial nerve function can be preserved in 88% of patients presenting with normal facial nerve function; serviceable hearing can be preserved in 92% of patients who present with normal hearing. A standard retrosigmoid craniotomy with drilling of the posterior canal wall of the internal auditory canal worked well in the majority of cases.

The classification of posterior petrous meningiomas and its clinical significance

This retrospective analysis of the clinical records of 42 patients was used to study the clinical significance of a classification system for posterior petrous meningiomas. According to clinical manifestations and radiological images, posterior petrous meningiomas were classified into three types: type I (cerebella type; 12 patients), tumours involved and compressed the cerebellum; type II (cranial nerve type; 16 patients), tumours involved the cranial nerves; and type III (combined type; 14 patients), tumours involved more than one structure such as the cerebellum, cranial nerves and the brain stem. All patients underwent microneurosurgery and the total resection rate was 90%. It was more difficult totally to resect type II and III tumours than type I tumours and the post-operative functional outcomes were worse. Microneurosurgical techniques and skills are critical to increase the total resection rate of posterior petrous meningiomas in order to decrease the mortality and disability rates.

Transpetrosal approaches for meningiomas of the posterior aspect of the petrous bone

OBJECTIVE

To assess outcome following excision of meningiomas of the posterior aspect of the petrous bone through transpetrosal approaches.

MATERIAL AND METHOD

We carried out a retrospective case-series study in a multidisciplinary tertiary care center on all patients who underwent meningiomas removal from January 1989 to September 2005. Surgical approaches were transpetrosal: widened retrolabyrinthine, translabyrinthine, transotic and transcochlear, occasionally combined with a subtemporal transtentorial approach. Epidemiology, symptoms, preoperative evaluation, surgery, postoperative complications and facial and auditory results were analyzed using standardized grading systems. The Desgeorges and Sterkers classification was used to assess tumor size and location.

RESULTS

Forty women and three men underwent surgery (mean age: 56.7). Medium-sized tumors stages 2 and 3 (84%) and AM and P localization (34% and 20.4%) predominated. In 65% of cases, the tumor extended beyond the CPA. Main presenting symptoms were balance disorders (72%) and sensorineural hearing loss (53.5%). Mortality was nil. A preoperative facial nerve paresis was present in 14% of patients. Tumor removal was complete in 79.1% of cases. At 1-year post-op, 73% of patients had a normal or subnormal facial function and 55% had serviceable hearing. A cerebrospinal fluid leakage occurred in 6.9%.

DISCUSSION

Posteriorly attached meningiomas are less symptomatic and of better prognosis than medially inserted ones. Transpetrosal approaches are reliable for the removal for all types and sizes of such tumors, and can be easily combined in the same procedure with a subtemporal transtentorial approach to remove extensions to the clivus and tentorium. They offer low morbidity and a high proportion of facial nerve and hearing preservation.

Gamma Knife surgery for benign meningioma

Object

Meningioma is the most frequent benign tumor treated with Gamma Knife surgery (GKS); however, the assessment of its efficacy and safety in slow-growing tumors is an ongoing process, requiring analysis of long-term results.

Methods

Three hundred sixty-eight patients harboring 400 meningiomas treated between 1992 and 1999 at Na Homolce Hospital were evaluated. The median patient age was 57 years (range 18–84 years). The median tumor volume was 4.4 cm3 (range 0.11–44.9 cm3). The median tumor margin dose to the 50% isodose line was 12.55 Gy (range 6.5–24 Gy). Descriptive analysis was performed in 331 patients (90%); 325 patients had a follow-up longer than 24 months (median 60 months), and six patients were included because of posttreatment complications. The volume of treated tumors decreased in 248 cases (69.7%), remained the same in 99 (27.8%), and increased in nine (2.5%). The actuarial tumor control rate was 97.9% at 5 years post-GKS. Perilesional edema after radiosurgery was confirmed on neuroim-aging in 51 patients (15.4%). The temporary and permanent morbidity rates after radiosurgery were 10.2 and 5.7%, respectively.

Results

A significantly higher incidence of tumor volume increase was observed in men compared with women and in tumors treated with a margin dose lower than 12 Gy. Significant risk factors for edema included an age greater than 60 years, no previous surgery, perilesional edema before radiosurgery, a tumor volume greater than 10 cm3, a tumor location in the anterior fossa, and a margin dose greater than 16 Gy.

Conclusions

Stereotactic radiosurgery is a safe method of treatment for meningiomas. A minimum margin dose of 12 to 16 Gy seems to represent the therapeutic window for benign meningiomas with a high tumor control rate in a mid-term follow-up period.

Vertigo as the sole presenting symptom of cerebellopontine angle meningioma

We report a rare case of cerebellopontine angle (CPA) meningioma whose sole symptom was severe vertigo. A 39-year-old woman with right CPA meningioma was referred for surgery. She experienced severe vertigo for 2 years without any other symptoms. Caloric test indicated right canal paresis of 90%. Her audiogram was normal. After surgery, vertigo symptoms disappeared dramatically. The mechanisms of restoration from vertigo are discussed.

Aggressive recurrence of intra-extradural cervico-thoracic meningothelial meningioma

The authors analysed the case of a 53-years-old woman who presented with an C5-D1 intra-extradural mass. Following subtotal removal, the tumour was histologically classified as meningothelial meningioma and no radiotherapy was recommended. The neuroradiological workup demonstrated that the lesion was stable one year after the operation but, a few months later a tumour recurrence with huge bone destruction was detected. The tumour was totally resected and a circumferential stabilization was performed. Histology remained unchanged but radiotherapy was now recommended. One year after a new recurrence was detected and the patient died. The authors discuss the extremely malignant behaviour of a tumour classified as benign.

Avantages de l’abord rétro-labyrinthique pour l’exérèse des méningiomes insérés au pourtour du coude du sinus latéral

PURPOSE

To describe the retrolabyrinthine approach for the resection of 9 meningiomas inserted around the lateral sinus between the transverse and sigmoid parts, to discuss the value of this approach compared to the retrosigmoid approach for resection of meningioma in this localization and to review the literature.

METHODS

Retrospective study. Between 1988 and 2002, 9 patients (8 female, mean age 50 years) underwent surgery via the retrolabyrinthine approach for resection of meningiomas inserted around the lateral sinus between the transverse and sigmoid parts.

RESULTS

Resection was total (8 Simpson I and 1 Simpson II) in all patients. In the early postoperative course, one patient was treated for meningitidis with an LCR leak and one patient present a temporary paresis of the vagus nerve. Mean follow-up was 5 years (6 months-10 years). All patients continued their pre-treatment occupation after surgery. No recurrence was observed.

CONCLUSION

Two approaches can be used for resection of meningiomas in this localization. The retrosigmoid approach is a common neurosurgical approach exposure of the cerobellopontine angle. It is practised by most neurosurgeons. Via this approach, the cerebellar lobe must be pushed back so the arteries feeding the tumor are in the operative field at the end of the procedure. For numerous authors the operative field is too narrow. On the other hand, the retrolabyrinthine approach described in 1972 by Hitselberger and Pulec allows exposure of feeding arteries during the first steps of operation, an easier resection of meningioma insertion and better control of the lateral sinus. This approach can be enlarged to the retrosigmoid or the subtemporal anatomic region.

Spinal Meningioma: Relationship Between Histological Subtypes and Surgical Outcome?

Intraspinal meningiomas are slow growing benign tumors that produce indolent neurological deficits, which are often reversible following operation. It is unclear, if there is a correlation between postoperative neurological restoration and histopathological parameters. The aim of the present work was to seek for existence of such parameters. Retrospectively, we reviewed the charts of 33 patients with spinal meningiomas who were operated on from January 1980 through December 1995. Histological classification was performed according to WHO criteria. Laminoplasty or hemilaminoplasty was performed in 29 patients (88%) and suboccipital craniotomy with cervical laminoplasty in 4 patients (12%). Mean age of the 30 women (91%) and the 3 men (9%) was 63+/-20 years (range 22-88). Spinal meningiomas were of high-cervical location in 9 (27%) and of low-cervico-thoracic location in 24 (73%) patients. Tumor position was laterally in 19 (58%), posteriorly in 8 (24%) and anteriorly in 6 (18%) patients. Histological classification was psammomatous in 22 (66%), fibroblastic in 7 (22%) and meningothelial in 4 (11%) patients. Following tumor resection, neurological deficits resolved in 26 of 33 patients (79%) and worsened in 7 of 33 patients (21%) all of the latter had meningiomas of the psammomatous type. Resection of psammomatous meningiomas of the spine is associated with a less favorable neurological outcome postoperatively than resection of spinal meningiomas of other pathological subtypes. Posterior or lateral tumor position in the spinal canal, location below C4, age less than 60 years, and duration of preoperative symptoms seem to be correlated with a good outcome.

Facial and Cochlear Nerve Function after Surgery of Cerebellopontine Angle Meningiomas

OBJECTIVE:

Meningiomas of the cerebellopontine angle (CPA) share a common location, but their site of dural origin and their relationship to surrounding neurovascular structures of the CPA are variable. The clinical presentation and outcome after surgical resection are different because of the diversity of this tumor entity. We report on a series of 421 patients with CPA meningiomas, with special emphasis on the analysis of the preoperative and postoperative facial and cochlear nerve function in relation to the site of dural attachment and main tumor location in the CPA cistern.

METHODS:

Among 421 patients, the charts of 347 patients with complete clinical data, including the history and audiograms, imaging studies, surgical records, discharge letters, histological records, and follow-up records, were reviewed retrospectively. Data about preoperative and postoperative facial nerve function were available in 334 patients, and audiometric analysis was conducted in 333 patients. Patients with neurofibromatosis Type 2 were excluded from the study.

RESULTS:

There were 270 women and 77 men, with a mean age of 53.4 years (range, 17.6–84 yr). Among these patients, 32.9% of the tumors originated at the petrous ridge anterior to the inner auditory canal (IAC) (Group 1), 22.2% showed involvement of the IAC (Group 2), 20.2% were located superior to the IAC (Group 3), 11.8% were inferior to the IAC (Group 4), and 12.9% were posterior to the IAC, originating between the IAC and the sigmoid sinus (Group 5). Patients presented with disturbance of Cranial Nerves V–VIII, the lower cranial nerves, and ataxia, depending on the main tumor location. Tumor resection was performed through a suboccipital-retrosigmoidal approach in the semisitting position in 95% of the patients. A combined supratentorial-infratentorial presigmoidal approach was performed in 5%. Total tumor removal (Simpson Grade 1 and 2) was achieved in 85.9% and subtotal removal in 14.1%. The best initial postoperative facial and auditory nerve function was observed in tumors belonging to Groups 3 and 5. Recovery from preoperative deafness was observed in 1.8% of patients. On long-term follow-up, good facial nerve function (House-Brackmann Grade 1 or 2) was observed in 88.9% of patients. Hearing preservation among patients with preoperative functional hearing was documented in 90.8% on long-term follow-up.

CONCLUSION:

Although the outcome of facial and cochlear nerve function is different in CPA meningiomas, depending on the topographic classification of these tumors, preservation of the cochlear nerve is possible in every tumor group and should be attempted in every patient with CPA meningioma. It has to be kept in mind that recovery of hearing was also observed in patients with preoperative profound hearing deficits.

Intraoperative auditory brainstem responses in patients with cerebellopontine angle meningiomas involving the inner auditory canal: analysis of the predictive value of the responses

Object. Meningiomas of the cerebellopontine angle (CPA) can either arise from or secondarily grow into the inner auditory canal (IAC). This location may have a great impact on hearing function following surgery to remove these lesions. The aim of this retrospective study was to investigate the reliability and predictive importance of auditory brainstem responses (ABRs) for the determination of postoperative auditory function in patients with CPA meningiomas in comparison with results obtained in patients who undergo surgery for vestibular schwannomas.

Methods. In a consecutive series of 1800 meningiomas surgically treated between 1978 and 2002, 421 lesions were located in the CPA. In 38 patients with CPA meningiomas involving the IAC, the findings of intraoperative ABR monitoring and the hearing status of each patient before and after surgery were retrospectively analyzed.

On analysis, ABR monitoring demonstrated stable findings in 24 patients throughout tumor resection and fluctuating signals in 10 patients. Among the 24 patients with stable ABRs, postoperative hearing function improved in three patients, remained the same in 15, and worsened in six patients, including one patient who displayed postoperative deafness. There was even one patient recovering from preoperative deafness. Among the 10 patients with unstable ABRs, intermittent decreases in amplitude and deformations of variable duration in the ABR wave were noted. The risk of deafness was considerably higher in patients with prolonged phases of intermittent ABR deterioration.

Conclusions. The presence and absence of ABRs during surgery for CPA meningiomas reliably predicted the presence and absence of postoperative auditory function. Intermittent deterioration of ABRs may result in postoperative deafness, depending on the duration of these events during surgery. Improvements in hearing are only seen when the ABRs are stable for amplitudes and latencies throughout surgery.

Posterior petrous meningiomas: 82 cases

Object. The aim of this study was to discuss posterior petrous meningiomas—their classification, clinical manifestations, surgical treatments, and patient outcomes.

Methods. A retrospective analysis was performed in 82 patients with posterior petrous meningiomas for microsurgery. According to the anatomical relationship with the posterior surface of the petrous bone and with special reference to the internal auditory canal (IAC), posterior petrous meningiomas were classified into three types: Type I, located laterally to the IAC (28 cases); Type II, located medially to the IAC, which might extend to the cavernous sinus and clivus (32 cases); and Type III, extensively attached to the posterior surface of the petrous bone, which might envelop the seventh and eighth cranial nerves (22 cases).

Sixty-eight (83%) of 82 cases involved total resection. The rate of anatomical preservation of facial nerve was 97.5%, whereas the functional preservation rate was 81%. The rate of hearing preservation was 67%. All Type I tumors were completely resected, and the rate of anatomical preservation of facial nerve was 100% and functional preservation was 93%. Regarding Type II lesions, 75% of 32 cases involved total resection; the rate of anatomical preservation of facial nerve was 97% and functional preservation was 75%. For Type III lesions, 73% of 22 cases were totally resected. The rate of anatomical preservation of facial nerve in patients with this tumor type was 95%, whereas functional preservation was 73%.

Conclusions. Clinical manifestations and surgical prognoses are different among the various types of posterior petrous meningiomas. It is more difficult for Types II and III tumors to be resected radically than Type I lesions, and postoperative functional outcomes are significantly worse accordingly. The primary principles in dealing with this disease entity include preservation of vital vascular and central nervous system structures and total resection of the tumor as much as possible.

Meningiomas of the posterior petrous bone: functional outcome after microsurgery

OBJECT

The aim of this study was to analyze a subgroup of patients harboring cerebellopontine angle meningiomas originating from the posterior petrous bone in regard to clinical presentation, surgical anatomy, complications, and long-term functional postoperative results.

METHODS

Data in a series of 51 patients with meningiomas of the posterior petrous bone who had undergone microsurgical treatment at the authors' institution between 1989 and 2002 were retrospectively reviewed. The patient population consisted of 46 women and five men with a mean age of 53 years (range 22-70 years). The main symptom on first admission was impaired hearing in 41%, dizziness in 20%, and tinnitus in 18% of the patients. Results of physical examination and audiological testing revealed hypacusis in 65% of patients, cerebellar ataxia in 31%, and impairment of the fifth cranial nerve in 26%. All patients underwent surgical treatment via a lateral suboccipital approach. Intraoperatively, the tumor was found to be attached to the postmeatal dura in 37%, the premeatal dura in 27.5%, the suprameatal dura in 19.6%, the inframeatal dura in 7.8%, and centered on the porus acusticus in 5.9% of cases. Tumor extension into the internal acoustic meatus was present in seven patients. Tumor resection was categorized as Grade I in 14 patients, Grade II in 29, Grade III in six, and Grade IV in two patients, according to the Simpson classification system. The site of displacement of the cranial nerves was predictable in up to 84% of patients, depending on the dural origin of the tumor as depicted on preoperative magnetic resonance (MR) imaging studies. Postoperatively, a new and permanent facial paresis was observed in five patients (9.8%). In 38 patients in whom both pre- and postoperative audiological data were available, hearing function deteriorated after surgery in 18.4% and improved in 7.9%. Clinical and MR imaging postsurgical data from a mean period of 5.8 years (range 13 months-13 years) were available in all patients. Forty-four patients (86%) resumed normal daily activity. Tumor recurrence was observed in two patients (3.9%), and both underwent a second surgery.

CONCLUSIONS

Preoperative detailed analysis of MR imaging data gives the surgeon a clue about the dislocation of critical neurovascular structures, particularly the cranial nerves. Nonetheless, the exact relationship of the cranial nerves to the tumor (dislocation, adherence, infiltration, and splaying of nerves) can only be fully appreciated during surgery.

Surgical management of posterior petrous meningiomas

Posterior petrous meningiomas (commonly termed posterior pyramid meningiomas and/or meningiomas of the posterior surface of the petrous pyramid) are the most common meningiomas of the posterior cranial fossa. They are located along the posterior surface of the temporal bone in the region of the cerebellopontine angle. They often mimic vestibular schwannomas, both clinically and on neuroimaging studies. Common clinical symptoms include hearing loss, cerebellar ataxia, and trigeminal neuropathy. The site of dural origin determines the direction of cranial nerve displacement. Total resection can be achieved in most cases with a low morbidity rate and an excellent prognosis. The authors review the surgical management of posterior petrous meningiomas.

[Cerebellopontine angle surgery. Part 2: Specific remarks]

OBJECTIVES

Cerebellopontine angle tumors are uncommon lesions that can potentially be cured by microsurgical removal. The primary objective of the surgical treatment differs between vestibular schwannoma and meningioma. This feature may be influenced by the site of tumor origin and displacement of neurovascular structures as well as by their different tumor biology.

METHODS

A review of the current literature was conducted.

RESULTS AND CONCLUSIONS

Relevant cranial nerves and vascular involvement as well as anatomical location with respect to the cerebellopontine angle are discussed for vestibular schwannoma and meningioma. The main factors influencing the surgical outcome are outlined with special reference to facial and cochlear nerve function and cerebrospinal fluid leakage. The retrosigmoid approach offers a comparable success rate for hearing conservation and probably a superior outcome in terms of facial nerve function when compared with the middle fossa approach. The intrameatal limitations of the retrosigmoid approach can be excluded by the intraoperative assistance of an endoscope. The advantages of endoscope-assisted surgery may include improved visualization of relevant structures, more complete tumor removal, and a lowered risk of cerebrospinal fluid leakage.