The effects of stereotactic radiosurgery on secondary facial pain

Radiosurgical Decompression of Trigeminal Nerve and Its Correlation with Functional Outcome in Tumor-Related Trigeminal Neuralgia

BACKGROUND

Target selection during Gamma Knife radiosurgery (GKRS) in cases of tumor-related trigeminal neuralgia is always debatable. We analyzed the correlation of regression of tumor size and degree of release of the nerve with long-term pain control.

METHODS

Between March 2012 and March 2023, 50 cases of tumor-related trigeminal neuralgia were treated with GKRS (tumor was targeted). Radiological findings after GKRS were categorized into 3 types: 1) tumor volume remained same or decreased, additional segment of nerve not seen; 2) tumor volume decreased, additional segment of trigeminal nerve seen, but tumor still adherent to the nerve; 3) tumor volume decreased, adjacent nerve seen completely separated from tumor. Pain score before and after GKRS (Barrow Neurological Institute I-III: good; Barrow Neurological Institute IV and V: poor) was correlated with these subgroups.

RESULTS

At median follow-up of 46.5 months, 18 cases showed type 1 radiological response, 23 showed type 2 response, and 9 showed type 3 response. Good pain control was achieved in 10 (55.5%) patients with type 1, 15 (65.21%) with type 2, and 7 (77.8%) with type 3 responses. The outcome differences among these 3 groups were not statistically significant (P = 0.519). Five patients with type 3 radiological response were off medication, which was statistically better than type 1 and type 2 radiological responses, with 3 patients (P = 0.012) and 2 patients (P = 0.002), respectively, still receiving medication.

CONCLUSIONS

Tumor volume reduction after GKRS may be associated with good pain control in tumor-related trigeminal neuralgia. Further, this allows visualization of additional segment of nerve that can be targeted in a second session for treating recurrent or failed cases.

Open surgery vs. stereotactic radiosurgery for tumour-related trigeminal neuralgia: A systematic review

BACKGROUND

Secondary trigeminal neuralgia is a facial pain in trigeminal nerve dermatome caused by an underlying disease, such as cerebellopontine angle tumours. Treatment options to relieve the pains were surgical tumour resection and stereotactic radiosurgery of the tumour or trigeminal nerve. This study aims to review the efficacy of open surgery and stereotactic radiosurgery and recommend the treatment of choice for secondary trigeminal neuralgia due to cerebellopontine angle tumours.

METHOD

The inclusion criteria were studies covering patients with trigeminal neuralgia associated with cerebellopontine angle tumours that were treated with either open surgery or stereotactic radiosurgery and reported pain outcomes after treatment. Non-English articles or studies with a population of less than five were excluded. We systematically searched studies from PubMed, Ebscohost, and Cochrane Library from inception until December 20, 2021. Several works of literature from manual search were also added. Selected articles were appraised using a critical appraisal tool for prognostic studies.

RESULT

Included articles were 26 retrospective studies and one prospective study comprising 517 patients. Of 127 schwannomas, 226 epidermoids, 154 meningiomas, and ten other tumours, 320 cases received surgical tumour excision with or without MVD, 196 had tumour-targeted radiosurgery, and 22 underwent nerve-targeted radiosurgery. In surgical series, 92.2 % gained pain improvement, 2.8 % were unchanged, and 4.5 % had recurrence; none of the patients had worsened outcomes. In cases treated with tumour-targeted radiosurgery, the improvement rate was 79.1 %, unchanged at 14.3 %, recurrence at 26.5 %, and worse symptoms rate after the intervention was 6.6 %. Six patients with recurrent pain after tumour-targeted radiosurgery received secondary nerve-targeted radiosurgery with improved outcomes. Only one patient in our review underwent primary nerve-targeted radiosurgery, and the result was satisfactory. One study treated 15 patients with a single session of tumour-targeted and nerve-targeted radiosurgery, with an improvement rate of 93.3 % and a recurrence rate of 21.4 %.

CONCLUSION

Open surgery releasing the nerve root from compressive lesions is advocated to be the first-line treatment to gain satisfactory outcomes. Total removal surgery is recommended if possible. Nerve-targeted radiosurgery should be reserved as a secondary treatment for recurrent cases.

Trigeminal Neuralgia Secondary to Meningiomas and Vestibular Schwannoma Is Improved after Stereotactic Radiosurgery: A Systematic Review and Meta-Analysis

INTRODUCTION

Trigeminal neuralgia (TN) secondary to tumors is encountered in up to 6% of patients with facial pain syndromes and is considered to be associated with tumors affecting the trigeminal nerve pathways. The most frequent are meningiomas and vestibular schwannomas (VS). Stereotactic radiosurgery (SRS) has emerged as a valuable treatment, with heterogeneity of clinical results. We sought to review the medical literature on TN treated with SRS for meningiomas and VS and investigate the rates of improvement of TN symptoms.

METHODS

We reviewed articles published between January 1990 and December 2019 in PubMed. Pain relief after SRS, the maintenance of pain relief, and TN recurrence and complications were evaluated with separate meta-analyses, taking into account the data on individual patients.

RESULTS

Pain relief after SRS was reported as Barrow Neurological Institute (BNI) pain intensity scores of BNI I in 50.5% (range 36-65.1%) of patients and BNI I-IIIb in 83.8% (range 77.8-89.8%). There was no significant difference in series discussing outcomes for tumor targeting versus tumor and nerve targeting. Recurrences were described in 34.7% (range 21.7-47.6; tumor targeting). Maintenance of BNI I was reported in 36.4% (range 20.1-52.7) and BNI I-IIIb in 41.2% (range 29.8-52.7; tumor targeting series). When both the nerve and the tumor were targeted, only 1 series reported 86.7% with BNI I-IIIb at last follow-up. Complications were encountered in 12.6% (range 6.3-18.8; tumor targeting series) of patients; however, they were much higher, as high as 26.7%, in the only study reporting them after targeting both the nerve and the tumor. The most common complication was facial numbness.

CONCLUSION

SRS for TNB secondary to benign tumors, such as meningiomas and VS, is associated with favorable clinical course, but less favorable than in idiopathic TN. There was, however, heterogeneity among reports and targeting approaches. Although targeting both the nerve and the tumor seemed to achieve better long-term results, the rate of complications was much higher and the number of patients treated was limited. Future clinical studies should focus on the standard reporting of clinical outcomes and randomization of targeting methods.

Intracavernous Hemangiopericytoma: Case Report and Review of the Literature

Intracavernous hemangiopericytoma/solitary fibrous tumor is an extremely rare tumor, with only seven cases reported. We present a case of intracavernous hemangiopericytoma/solitary fibrous tumor and review all cases reported in the literature. A 67-year-old man experienced numbness over the left half of the face. Magnetic resonance imaging revealed a left intracavernous tumor extending into Meckel’s cave and the posterior fossa. We performed gamma knife surgery (GKS) which a prescribed dose to the tumor of 12 Gy, but tumor recurred 43 months after GKS. We performed partial tumor resection via a subtemporal interdural approach. The pathological diagnosis was hemangiopericytoma. Postoperatively, we performed second GKS with a prescribed dose of 15 Gy. Diplopia and ptosis improved markedly and the tumor initially reduced in size, but tumor regrowth was seen again 29 months after second GKS. Third GKS was performed with a prescribed dose of 15 Gy. Recurrence was not seen at 18 months after third GKS, but was identified about 2 years after third GKS. We performed fourth GKS with a prescribed dose to the residual tumor of 16 Gy. We report a rare case of intracavernous hemangiopericytoma originating in the cavernous sinus, but distinguishing between hemangiopericytoma and schwannoma is difficult for round, intracavernous tumors showing homogeneous enhancement without flow voids. GKS might be one of the options for residual and recurrent intracavernous hemangiopericytomas.

Fractionated Gamma Knife Radiosurgery as Initial Treatment for Large Skull Base Meningioma

We present our experience on the hypofractionated Gamma Knife radiosurgery (FGKS) for large skull base meningioma as an initial treatment. We retrospectively reviewed 23 patients with large skull base meningioma ≥10 cm³ who underwent FGKS as the initial treatment option. The mean volume of tumors prior to radiosurgery was 21.2±15.63 cm³ (range, 10.09~71.42). The median total margin dose and marginal dose per fraction were 18 Gy (range, 15~20) and 6 Gy (range, 5~6), respectively. Patients underwent three or four fractionations in consecutive days with the same Leksell® frame. The mean follow-up duration was 38 months (range, 17~78). There was no mortality. At the last follow-up, the tumor volume was stationary in 15 patients (65.2%) and had decreased in 8 patients (34.8%). Six patients who had cranial neuropathy at the time of FGKS showed improvement at the last clinical follow-up. Following FGKS, 4 patients (17%) had new cranial neuropathy. The trigeminal neuropathy was the most common and all were transient. The mean Karnofsky Performance Status score at pre-FGKS and the last clinical follow-up was 97.0±10.4 points (median, 100) and 98.6±6.9 (median, 100) points, respectively. FGKS has showed satisfactory tumor control with functional preservation for large skull base meningiomas. Further prospective studies of large cohorts with long term follow-up are required to clarify the efficacy in the tumor control and functional outcome as well as radiation toxicity.

Management of Skull Base Tumor-Associated Facial Pain

Cancer-associated facial pain can be caused by a variety of pathologic conditions. Here the authors describe the symptoms and incidence of facial pain secondary to three separate anatomic subcategories of cancer. The authors subsequently discuss the effectiveness and drawbacks of the most common methods of treatment.

Five fraction image-guided radiosurgery for primary and recurrent meningiomas

PURPOSE

Benign tumors that arise from the meninges can be difficult to treat due to their potentially large size and proximity to critical structures such as cranial nerves and sinuses. Single fraction radiosurgery may increase the risk of symptomatic peritumoral edema. In this study, we report our results on the efficacy and safety of five fraction image-guided radiosurgery for benign meningiomas.

MATERIALS/METHODS

Clinical and radiographic data from 38 patients treated with five fraction radiosurgery were reviewed retrospectively. Mean tumor volume was 3.83 mm(3) (range, 1.08-20.79 mm(3)). Radiation was delivered using the CyberKnife, a frameless robotic image-guided radiosurgery system with a median total dose of 25 Gy (range, 25-35 Gy).

RESULTS

The median follow-up was 20 months. Acute toxicity was minimal with eight patients (21%) requiring a short course of steroids for headache at the end of treatment. Pre-treatment neurological symptoms were present in 24 patients (63.2%). Post treatment, neurological symptoms resolved completely in 14 patients (58.3%), and were persistent in eight patients (33.3%). There were no local failures, 24 tumors remained stable (64%) and 14 regressed (36%). Pre-treatment peritumoral edema was observed in five patients (13.2%). Post-treatment asymptomatic peritumoral edema developed in five additional patients (13.2%). On multivariate analysis, pre-treatment peritumoral edema and location adjacent to a large vein were significant risk factors for radiographic post-treatment edema (p = 0.001 and p = 0.026 respectively).

CONCLUSION

These results suggest that five fraction image-guided radiosurgery is well tolerated with a response rate for neurologic symptoms that is similar to other standard treatment options. Rates of peritumoral edema and new cranial nerve deficits following five fraction radiosurgery were low. Longer follow-up is required to validate the safety and long-term effectiveness of this treatment approach.

Stereotactic radiosurgery for trigeminal pain secondary to benign skull base tumors

OBJECTIVE

To assess the outcome of stereotactic radiosurgery (SRS) for patients with benign skull base tumors and trigeminal-related facial pain.

METHODS

We undertook a retrospective review of 31 consecutive patients (25 women, 6 men) with benign skull base tumors and trigeminal pain who underwent SRS between 1991 and 2008. The tumors included 17 posterior fossa meningiomas, 9 cavernous sinus meningiomas, and 5 trigeminal schwannomas. The median patient age was 62 years (range, 17-81 years). In all cases the tumor was the primary target for SRS. The median follow-up after SRS was 50 months (range, 12-184 months).

RESULTS

The actuarial tumor control rate after SRS was 95% at both 3 years and 5 years. Eighteen patients (58%) initially achieved complete resolution of trigeminal pain. Higher maximum dose was associated with initial complete pain resolution on a multivariate analysis. However, 7 patients had recurrent pain during follow-up. At last follow-up, only 7 patients (23%) remained pain-free off medications. Further treatment in addition to medical therapy was required for 6 patients (19%).

CONCLUSION

Although SRS offers excellent radiographic tumor control for benign skull base tumors, durable relief of tumor-related trigeminal pain without medication was noted in only one-fourth of patients at last follow-up.

Current concepts in stereotactic radiosurgery - a neurosurgical and radiooncological point of view

Stereotactic radiosurgery is related to the history of "radiotherapy" and "stereotactic neurosurgery". The concepts for neurosurgeons and radiooncologists have been changed during the last decade and have also transformed neurosurgery. The gamma knife and the stereotactically modified linear accelerator (LINAC) are radiosurgical equipments to treat predetermined intracranial targets through the intact skull without damaging the surrounding normal brain tissue. These technical developments allow a more precise intracranial lesion control and offer even more conformal dose plans for irregularly shaped lesions. Histological determination by stereotactic biopsy remains the basis for any otherwise undefined intracranial lesion. As a minimal approach, it allows functional preservation, low risk and high sensitivity. Long-term results have been published for various indications. The impact of radiosurgery is presented for the management of gliomas, metastases, brain stem lesions, benign tumours and vascular malformations and selected functional disorders such as trigeminal neuralgia. In AVM's it can be performed as part of a multimodality strategy including resection or endovascular embolisation. Finally, the technological advances in radiation oncology as well as stereotactic neurosurgery have led to significant improvements in radiosurgical treatment opportunities. Novel indications are currently under investigation. The combination of both, the neurosurgical and the radiooncological expertise, will help to minimize the risk for the patient while achieving a greater treatment success.

Stereotactic radiotherapy for the treatment of nonacoustic schwannomas

OBJECTIVE

Nonacoustic schwannomas are rare tumors in contrast to the most common neuromas of Cranial Nerve VIII. The current treatment of choice in these cases is microsurgical resection, but the risk of postoperative complications is high, especially in cavernous sinus-invading tumors. In many of these cases, it is not possible to achieve complete tumor removal, resulting in the probability of recurrences. For those patients, radiosurgery (RS) or stereotactic radiotherapy (SRT) can offer an alternate treatment.

METHODS

Within a 5-year period (2000-2005), 19 intracranial nonacoustic neuromas were treated with SRT-13 trigeminal neuromas, five neuromas of the lower cranial nerves (jugular foramen), and one located in the orbital region. Of these cases, there were nine women and 10 men who were, on average, 54 years of age (range, 33-83 yr). Eight patients had previously undergone surgery elsewhere and showed progressive tumor growth. All 19 patients were treated with SRT: 15 with normal fractions of 1.8-2 Gy single dose up to 54-59.4 Gy. Their irregular tumor volume ranged from 4.2 to 43.1 ccm (average: 14.1 ccm). Hypofractionation with 6 to 7 x 5 Gy was applied in four cases with an average tumor volume of 4.1 ccm (2.2-6.2 ccm). Clinical results and the efficacy for tumor control with an average follow-up of 35 months (11-63 mo) were evaluated.

RESULTS

Local tumor control rate was 95% (18 of 19 cases): one patient previously operated on had a recurrence of tumor progression after SRT, followed by a second subtotal resection. A tumor regression was proved in 11 cases (one neuroma disappeared and four patients had tumor shrinkage of more than 50%, the other six experienced shrinkage between 20% and 40%). Within the first 6 months, two patients developed temporarily increased tumor volume as well as a confirmed reaction to irradiation. In one of these two cases, there were mild side effects according to CTC Grade I. No patient experienced a new or increased neurological deficit. Improvement of their cranial nerve disturbances was achieved in 11 of 19 patients and the other eight showed no clinical changes. The mostly moderate trigeminal pain decreased slowly.

CONCLUSION

SRT is a low-risk and effective treatment option for intracranial neuromas. Particularly in cases of sinus cavernous-invading trigeminal and in jugular foramen tumors, SRT can be the treatment of choice. Concerning tumor regression, SRT is as effective as RS.

Functional outcome of patients with benign meningioma treated by 3D conformal irradiation with a combination of photons and protons

PURPOSE

To evaluate efficacy and tolerance of external fractionated combination of photon and proton radiation therapy (RT) for intracranial benign meningiomas.

METHODS AND MATERIALS

Between 1994 and 2002, 51 patients with intracranial meningiomas of the base of the skull were treated with a combination of photon and proton RT. Median total dose was 60.6 cobalt Gy equivalent (54-64). One hundred eight eye-related symptoms were collected; 80 other symptoms were noted and followed up.

RESULTS

Mean follow-up was 25.4 months. Acute tolerance was excellent. Out of the 108 eye-related symptoms, 106 (96%) were evaluated. Improvements were reported for 73 (68.8%) of them. Out of the 88 other miscellaneous symptoms, 81 (92%) were evaluated. Improvements were reported in 54 cases (67%). Median time to improvement ranged from 1 to 24 months after completion of the radiotherapy, depending on the symptom. We did not observe any worsening of primary clinical signs. Radiologically, 1 patient relapsed 4 months after the end of irradiation. Pathology revealed a malignant (Grade 3) transformation of the initial Grade 1 meningioma. Four-year local control and overall survival rates were, respectively, 98% and 100%. Stabilization of the tumor was observed in 38 cases (72%), volume reduction in 10 cases (20%), and intratumor necrosis in 3 cases. Two patients complained of Grade 3 side effects: 1 unilateral hearing loss requiring aid and 1 case of complete pituitary deficiency.

CONCLUSION

These results stressed the clinical efficacy of fractionated-associated photon-proton RT in the treatment of meningiomas, especially on cranial nerve palsies, without severe toxicity in almost all patients.

Cavernous Malformation of the Trigeminal Nerve Manifesting with Trigeminal Neuralgia: Case Report

OBJECTIVE AND IMPORTANCE:

We describe a patient with a cavernous malformation within the trigeminal nerve at the nerve root entry zone who presented with trigeminal neuralgia.

CLINICAL PRESENTATION:

A 52-year-old woman sought treatment after experiencing dizziness and lancinating left facial pain for almost a year. Neurological examination revealed diminished sensation in the distribution of the trigeminal nerve on the left. Magnetic resonance imaging demonstrated a minimally enhancing lesion affecting the trigeminal nerve.

INTERVENTION:

The patient underwent a retrosigmoid craniotomy. At the nerve root entry zone, the trigeminal nerve was edematous with hemosiderin staining. The lesion, which was resected with microsurgical technique, had the appearance of a cavernous malformation on gross and histological examination. The patient's pain improved significantly after resection.

CONCLUSION:

Cavernous malformations can afflict the trigeminal nerve and cause trigeminal neuralgia. Microsurgical excision can be performed safely and is associated with improvement in symptoms.

Intensity modulated radiotherapy (IMRT) for recurrent, residual, or untreated skull-base meningiomas: preliminary clinical experience

OBJECTIVE

To investigate the feasibility of using intensity modulated radiotherapy (IMRT) for complex-shaped benign meningiomas of the skull base and report clinical experience.

METHODS

Twenty patients with benign skull-base meningiomas WHO degrees I (histopathologically proven in 16/20) were treated with IMRT between June 1998 and August 1999. Each tumor was complex in shape and adherent to, or encompassed, organs at risk (cranial nerves, optic apparatus, and brainstem). All patients, immobilized in a customized head mask integrated into a stereotactic system, were planned on an inverse treatment planning system using 5 or 7 coplanar, equidistant beams and 5 intensity steps. Each treatment plan was verified extensively before treatment. Follow-up with MRI and clinical examination was performed at 6 and 18 weeks and every 6 months thereafter.

RESULTS

Target volumes ranged from 27 to 278 cc (median: 108 cc). Mean dose in 32 fractions ranged between 55.8 and 58.2 Gy. At median follow-up of 36 months (range: 31-43 months), pre-existing neurologic symptoms improved in 12/20 (60%), remained stable in 7/20 (35%), and worsened in 1 (5%) patient. Radiographic follow-up revealed significant tumor shrinkage 6 weeks post-IMRT in 2 patients and partial remission in 3 more patients at 9-17 months; other tumor volumes remained stable. There was no radiation-induced peritumoral edema, increase in tumor size, or new onset of neurologic deficits. Transient acute treatment side effects included nausea and vomiting and single occurrences of conjunctivitis/increased tearing and serous tympanitis.

CONCLUSION

IMRT in the treatment of central nervous system meningiomas is feasible and safe, offering highly conformal irradiation for complex-shaped skull-base tumors while sparing adjacent critical structures. If the tumor remissions seen here are found in the ongoing treatments, IMRT may be considered the treatment of choice for inoperable or subtotally resected meningiomas and for otherwise difficult-to-treat, complex-shaped tumors of the central nervous system adjacent to critical structures, with the potential of dose escalation for malignant tumors.

Stereotactic radiosurgery for brain tumors

In the 50 years since Leksell developed the concepts and initial hardware for modern brain radiosurgery, the treatment has progressed to the point where it is used commonly for arteriovenous malformations, benign masses, and metastases. Radiosurgery offers patients an effective treatment of life-threatening lesions with a reasonably low risk for discomfort and injury. In the 1990s, the procedure was used widely as primary and adjuvant treatment. The difficulty of defining the boundaries of primary brain cancers makes determining treatment targets problematic. Better imaging and computing offer a bright future for the technology.

Advances in stereotactic radiosurgery for brain neoplasms

It has been nearly half a century since Leksell introduced brain radiosurgery. In the past decade, the procedure has become widely used as both a primary and adjuvant treatment. Radiosurgery is now commonly employed for arteriovenous malformations, brain metastases, and several benign lesions. Its use in primary brain malignancy remains of uncertain benefit. Improvements in imaging, hardware, and software promise an even greater role for the technique.

Gamma knife radiosurgery for idiopathic and secondary trigeminal neuralgia

Object. The aim of this study was to identify pain relief and treatment morbidity following gamma knife radiosurgery (GKS) for idiopathic and secondary trigeminal neuralgia.

Methods. Between May 1992 and December 1999, 15 patients with idiopathic trigeminal neuralgia and 38 patients with secondary trigeminal neuralgia were treated with GKS. Pain improvement was achieved in 13 of the patients with idiopathic pain (pain response rate 86.7%). Seven patients were pain free and another six experienced pain reduction. There were no serious complications; however, two patients suffered a mild facial sensory change 8 months and 9 months, respectively, after GKS.

The patients with secondary trigeminal neuralgia were divided into two groups (Group I, 32 patients in whom the trigeminal root entry zone [REZ] near the tumor could not be visualized; and Group II, six patients in whom the trigeminal REZ near the tumor or brainstem lesion could be visualized).

In Group I, the pain subsided completely in eight patients and was reduced in seven (pain response rate 46.9%). In Group II, the pain subsided completely in one patient at 2.8 months and was reduced in three patients at a mean follow up of 0.8 months (range 0.6–1 month) after GKS. The pain response rate was 66.7%.

Conclusions. The authors believe that GKS is an effective treatment modalities for idiopathic and secondary trigeminal neuralgia, particularly in patients with inoperable lesions.

Gamma knife radiosurgery in the management of cavernous sinus meningiomas

Object. The authors sought to assess the functional tolerance and tumor control rate of cavernous sinus meningiomas treated by gamma knife radiosurgery (GKS).

Methods. Between July 1992 and October 1998, 92 patients harboring benign cavernous sinus meningiomas underwent GKS. The present study is concerned with the first 80 consecutive patients (63 women and 17 men). Gamma knife radiosurgery was performed as an alternative to surgical removal in 50 cases and as an adjuvant to microsurgery in 30 cases. The mean patient age was 49 years (range 6–71 years). The mean tumor volume was 5.8 cm3 (range 0.9–18.6 cm3). On magnetic resonance (MR) imaging the tumor was confined in 66 cases and extensive in 14 cases. The mean prescription dose was 28 Gy (range 12–50 Gy), delivered with an average of eight isocenters (range two–18). The median peripheral isodose was 50% (range 30–70%). Patients were evaluated at 6 months, and at 1, 2, 3, 5, and 7 years after GKS.

The median follow-up period was 30.5 months (range 12–79 months). Tumor stabilization after GKS was noted in 51 patients, tumor shrinkage in 25 patients, and enlargement in four patients requiring surgical removal in two cases. The 5-year actuarial progression-free survival was 92.8%. No new oculomotor deficit was observed. Among the 54 patients with oculomotor nerve deficits, 15 improved, eight recovered, and one worsened. Among the 13 patients with trigeminal neuralgia, one worsened (contemporary of tumor growing), five remained unchanged, four improved, and three recovered. In a patient with a remnant surrounding the optic nerve and preoperative low vision (3/10) the decision was to treat the lesion and deliberately sacrifice the residual visual acuity. Only one transient unexpected optic neuropathy has been observed. One case of delayed intracavernous carotid artery occlusion occurred 3 months after GKS, without permanent deficit. Another patient presented with partial complex seizures 18 months after GKS. All cases of tumor growth and neurological deficits observed after GKS occurred before the use of GammaPlan. Since the initiation of systematic use of stereotactic MR imaging and computer-assisted modern dose planning, no more side effects or cases of tumor growth have occurred.

Conclusions. Gamma knife radiosurgery was found to be an effective low morbidity—related tool for the treatment of cavernous sinus meningioma. In a significant number of patients, oculomotor functional restoration was observed. The treatment appears to be an alternative to surgical removal of confined enclosed cavernous sinus meningioma and should be proposed as an adjuvant to surgery in case of extensive meningiomas.