Gamma Knife Radiosurgery of Skull Base Meningiomas

Summary  Background. The standart surgical treatment of meningiomas is total resection of the tumour. The complete removal of skull base meningiomas can be difficult because of the proximity of cranial nerves. Stereotactic radiosurgery (SRS) is an effective therapy, either for adjuvant treatment in case of subtotal or partial tumour resection, or as solitary treatment in asymptomatic meningiomas.  Method. Between September 1992 and October 1995, SRS using the Leksell Gamma Knife was performed on 46 patients (f:m=35:15), ranging in age from 35 to 81 years, with skull base meningiomas at the Neurosurgical Department of the University of Vienna. According to the indication of gamma knife radiosurgery (GKRS) the patients (n=46) were devided into two subgroups. Group I (combined procedure: subtotal resection followed by GKRS as a planned procedure or because of a recurrent meningioma), group II (GKRS as the primary treatment). Histological examination of tumour tissue was available for 31 patients (67%) after surgery covering 25 benign (81%) and 6 malignant (19%) meningioma subtypes.  Findings. The overall tumour control rate after a mean follow-up period of 48 months (ranging from 36 to 76 months) was 96% (97.5% in benign and 83% in malignant meningiomas). Group I displayed a 96.7% tumour control rate, followed by group II with 93.3% respectively. Neurological follow-up showed an improvement in 33%, stable clinical course in 58% and a persistant deterioration of clinical symtoms in 9%. Remarkable neurological improvement after GKRS was observed in group II (47%), whereas in group I (26%) the amelioration of symptoms was less pronounced.  Interpretation. GKRS in meningiomas is a safe and effective treatment. A good tumour control and low morbidity rate was achieved in both groups (I, II) of our series, either as a primary or adjunctive therapeutic approach. The planned combination of microsurgery and GKRS extends the therapeutic spectrum in the treatment of meningiomas. Reduction of tumour volume, increasing the distance to the optical pathways and the knowledge of the actual growing tendency by histological evaluation of the tumour minimises the risk of morbidity and local regrowth. Small and sharply demarcated tumours are in general ideal candidates for single high dose-GKRS, even after failed surgery and radiation therapy, and in special cases also in larger tumour sizes with an adapted/reduced margine dose.     

Long-Term Outcome of Gamma Knife Radiosurgery for Vestibular Schwannoma

Objective We evaluated the long-term outcome of vestibular schwannoma (VS) treated with gamma knife radiosurgery (GKRS) as a primary treatment as well as an adjunct therapy. Materials and Methods We performed a retrospective review (2000–2012) of 82 patients with VS who received GKRS. Of 82 patients, 20 patients with prior resection received GKRS treatment as an adjunct therapy. The remainder of the patients (62) received GKRS as a primary treatment. Results GKRS for VS showed significant variations in tumor growth control (decreased in 44 patients [54%], arrested growth in 30 patients [36%], and increased tumor size in 8 patients [10%]). Progression-free survival rates after GKRS at 3, 5, and 10 years were 98%, 95%, and 95%, respectively. Hearing, facial nerve function, and Karnofsky performance scale were significantly improved after GKRS compared with pretreated status (79 versus 90). Two patients (2.5%) required resection again due to tumor progression and worsening of signs and symptoms. Conclusion Long-term follow-up demonstrated that GKRS offers a high rate of tumor control, preservation of multiple nerve functions, and a good quality of life in both new and recurrent patients with VS.     

Gamma Knife Radiosurgery for Glomus Jugulare Tumours

Summary  The aim of this clinical study was to determine the tumour control rate, clinical outcome and complication rate following gamma knife treatment for glomus jugulare tumours. Between May 1992 and May 1998, 13 patients with glomus tumours underwent stereotactic radiosurgical treatment in our department. The age of these patients ranged from 21 to 80 years. The male : female ratio was 2 : 11. Six patients had primary open surgery for partial removal or recurrent growth and subsequent radiosurgical therapy. Radiosurgery was performed as primary treatment in 7 cases. The median tumour volume was 6,4 cm³ (range: 4,6–13,7 cm³). The median marginal dose applied to an average isodose volume of 50% (30–50%) was 13,5 Gy (12–20 Gy). In 10 patients, a total of 48 MRI and CT follow-up scans were available. The remaining three patients have been excluded from the postradiosurgical evaluation since the observation time (t<12 months) was too short or patients were lost to follow up. The median interval from Gamma Knife treatment to the last radiological follow-up was 37,6 months (5–68 months). In 4 patients (40%) decreased tumour volumes were observed and in 6 cases (60%) the tumour size remained unchanged. Neurological follow-up examinations revealed improved clinical status in 5 patients (50%), a stable neurological status in 5 patients (50%) and no complications occurred. According to our preliminary experience Gamma Knife radiosurgery represents an effective treatment option for glomus jugulare tumours.     

Outcomes and Complications of Gamma Knife Radiosurgery for Skull Base Meningiomas

Objective To review the outcomes and complications of meningiomas treated with gamma knife radiosurgery (GKRS) as a primary treatment as well as an adjunct therapy. Materials and Methods We performed a retrospective review (2000–2013) of 136 patients with meningiomas who received GKRS. Of 136 patients, 68 patients had recurrent or residual tumors after microsurgical resection, and the other 68 patients received GKRS alone. The study population was evaluated clinically and radiographically after GKRS treatment. Results GKRS in meningiomas showed significant variations in tumor growth control (decreased in 69 patients [50.7%], arrested growth in 47 patients [34.6%], and increased tumor size in 20 patients [14.7%]). Progression-free survival rates after GKRS at 3, 5, and 10 years were 98%, 95% and 85%, respectively. Overall improvement of signs and symptoms after GKRS was 30% (71% versus 41%) compared with pretreated sign and symptoms (p = 0.0001). The Karnofsky performance scale was significantly improved after GKRS compared with the pretreated status (92 versus 80). Twenty patients (14.7%) required resection after initial GKRS. Conclusion These study findings revealed that GKRS offers a high rate of tumor control, preservation of multiple nerve functions, and a good quality of life in both new and recurrent patients with meningiomas.     

Radiosurgery of Intracranial Cavernous Malformations

Summary.  Background: The efficacy of radiosurgery in cases of surgically high risk symptomatic cavernous malformations (CMs) for reducing haemorrhagic risk and for seizure control has not been clearly documented and the radiation-induced complications of radiosurgery remain problematic. The authors present a retrospective clinical analysis of 22 cases of CMs treated by radiosurgery.  Methods: Twenty-two patients with symptomatic CMs were treated by linear accelerator (LINAC) radiosurgery or Gamma knife (GK) between 1995 and 1998. Medical records including radiological investigations were carefully reviewed to the last follow-up. The mean age of the patients was 34.1 years (12–56) and the male to female ratio was 12:10. Twenty patients reported at least one episode of bleeding and four had undergone microsurgery before radiosurgery. The remaining two patients presented with seizure without evidence of recent haemorrhage. In 16 cases, the CMs were deep-seated, and the others were located in the cerebral hemispheres; four were located at an eloquent area. LINAC radiosurgery using computed tomography scan was performed in 11 cases until May 1997, after which GK radiosurgery using magnetic resonance (MR) image was performed in 11 cases. The volume of the lesion ranged from 0.09 cc to 4.8 cc (mean 1.42 cc) and the mean marginal dose was 16.1 Gy (8–24). The median follow-up period after radiosurgery was 38.3 months (21–67). The rate of haemorrhage, seizure, and neurological deterioration following radiosurgery was analyzed, and the rate of haemorrhage was compared to that seen in natural course reports.  Findings: There was one case of haemorrhage during the follow-up period and the seizure was well controlled with anticonvulsants. In the group with prior haemorrhage, the bleeding rate of cavernous malformation after radiosurgery (1.55%/year) was lower than that of pre-radiosurgical period (35.5%/year, t=1.296, P=0.04). Six patients showed neurological deterioration following radiosurgery, however, the neurological deficits persisted in only two of the patients with LINAC. The radiosurgical modality (LINAC vs. GK) showed a possible correlation to radiation induced neurological deficits (P=0.06). On the MR images at the last follow-up, the lesion was decreased in eleven patients, increased in one, and no change was found in 10 cases. The T2 weighted MR images revealed a perilesional high signal change in nine patients. This signal change was not statistically related to lesion size (P=0.236), location (P=0.658), nor radiation dose (P=0.363), but was dependent on the treatment modality (P=0.02). New-enhancing lesion and a new cyst were each found in one case, respectively, during the follow-up.  Interpretation: Radiosurgery may be a good alternative option for treatment of surgically high risk CMs. However, the optimal radiosurgical technique, dose adjustment, and proper delineation of the mass are prerequisites. Radiosurgery induced complications are still problematic and post-radiosurgery MR image changes need to be further elucidated. Published online September 2, 2002 Acknowledgment  This work was partly supported by grants from the Clinical Research Institute, Seoul National University Hospital. Correspondence: Dong Gyu Kim, M.D., Department of Neurosurgery, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea.     

Stereotactic Radiosurgery for Tentorial Meningiomas

Summary Radical microsurgical resection is the procedure of choice for tentorial meningiomas. Despite advances in microsurgery, tentorial meningiomas continue to challenge surgeons and patients. To evaluate the response of tentorial meningiomas, we evaluated 41 patients who had Gamma knife stereotactic radiosurgery during a 9 year period. Patient age varied from 32 to 79 years. Headache, trigeminal neuralgia, or facial paraesthesia were the most common presenting symptoms. Sensory deficits in the distribution of the trigeminal nerve were the most common finding. Eighteen patients (44%) had undergone between 1 and 5 (mean, 1.9) resections prior to radiosurgery; 23 had tumors diagnosed by neuroimaging. The average tumor diameter in this series was 20 mm. The maximum tumor dose varied from 24 to 40 Gy (mean, 30.5 Gy), and the tumor margin dose varied from 12 to 20 Gy (mean, 15.3 Gy). During the average follow-up interval of 3 years (range, 1–8 years), 19 patients had clinical improvement, 20 remained stable, and 2 patients deteriorated. Follow-up imaging showed a reduction in tumor size in 18 patients, no further tumor growth in 22, and an increase in tumor size in one (overall tumor control rate of 98%). Stereotactic radiosurgery using the Gamma Knife was a safe and effective primary or adjuvant treatment for patients with tentorial meningiomas.     

Long-term Outcomes of Gamma Knife Surgery for Posterior Fossa Arteriovenous Malformations

The long-term outcomes of gamma knife surgery (GKS) in patients with posterior fossa arteriovenous malformations (AVMs) were retrospectively analyzed in 82 patients followed up for more than 5 years to evaluate the efficacy and safety. The median AVM volume at GKS was 0.95 cm³. The prescribed dose to the AVM margin was median 18 Gy with 1–18 isocenters. The actual complete AVM obliteration rate was 58.5% at 3 years and 78.0% at 5 years. The significant factors for higher complete obliteration rate were younger patient age and smaller maximum/minimum nidus diameter ratio. Two patients experienced hemorrhage caused by residual AVM rupture at 4 and 49 months. Twenty patients developed peri-nidal edema as an adverse radiation-induced reaction at median 13 months. One patient developed radiation-induced necrosis at 6.8 years. Neurological complication was observed in 12 patients and 6 patients remained with neurological dysfunction permanently. Larger nidus volume and location adjacent to an eloquent area significantly increased the risk of neurological complication. Pittsburgh radiosurgery-based AVM grading scale was significantly correlated with the outcome of neurological symptoms after GKS. GKS achieved acceptable and complete obliteration rate for posterior fossa AVM with relatively low risk of morbidity on neuroimaging and neurological symptoms for the long-term period after treatment. We recommend conformable and selective treatment planning to achieve both obliteration of the AVM nidus and preservation of neurological function.     

Gamma knife radiosurgery for intracranial haemangioblastomas

Summary Background. The results of gamma knife radiosurgery for haemangioblastomas were retrospectively studied to assess the efficacy for tumour growth control and clarify the clinical indications for gamma knife radiosurgery in these tumours. Methods. The medical records of 22 patients with 67 tumours, 12 men and 10 women aged 20–73 years (mean 51.9 years), who underwent gamma knife radiosurgery for haemangioblastomas between January 1993 and January 2006, were retrospectively reviewed. Ten patients with 54 lesions had von Hippel-Lindau disease. The mean tumour volume was 1.69 cm³ (range 0.0097–16.4 cm³). Nineteen patients had undergone 1–4 open surgery procedures (mean 1.5) before gamma knife radiosurgery. Tumours without a cystic component, (the solid type), were found in 54 lesions and tumours associated with cyst, (the mural nodule with cyst type), in 13 lesions. The marginal dose was 8–30 Gy (mean 14.0 Gy). Findings. Follow-up magnetic resonance (MR) imaging was performed at 9–146 months (mean 63 months). The control rate for tumour growth was 83.6%. The only factor affecting tumour growth control was the presence of a cystic component at the time of gamma knife radiosurgery in both univariate and multivariate analysis. No complication such as radiation-induced peritumoural oedema or radiation necrosis occurred. Conclusion. The presence of cystic components at the time of gamma knife radiosurgery was the only factor significantly correlated with unfavourable tumour growth control by gamma knife radiosurgery for haemangioblastomas. Gamma knife radiosurgery is effective for solid type tumours, even if the marginal dose is relatively low. Surgical removal is recommended for mural nodule with cyst type tumours, when possible.     

Gamma knife radiosurgery for circumscribed choroidal hemangioma

Summary The authors report a case of circumscribed choroidal hemangioma (CCH) treated by stereotactic radiosurgery with gamma knife. A thirteen-year-old boy presented with a 4-year history of progressive visual loss in his right eye. Because of the large size and fluid collection under the macula, gamma knife radiosurgery was done. During 2 years of follow-up, there was resolution of retinal detachment, regression in tumor thickness, and no complications. Gamma knife radiosurgery may be a reasonable alternative treatment option for symptomatic CCHs which are difficult to manage using standard therapeutic options such as photocoagulation.     

伽玛刀治疗原发性三叉神经痛的临床研究

目的探讨伽玛刀(γ刀)立体定向放射外科治疗原发性三叉神经痛(trigeminal neuralgia,TN)的方法和疗效。方法对49例TN患者采用磁共振扫描、Gamma 2TPS系统定位、剂量规划后,采用OUR-XGDγ刀行三叉神经痛立体定向放射外科治疗。治疗靶点位于三叉神经根近脑干侧,其中44例采用双4 mm准直器,另外5例采用单4 mm准直器,放射中心剂量为60~80 Gy,平均(71.7±9.3)Gy。结果经3~36月随访观察,平均(26.0±7.3)月。依据Brisman三叉神经疼痛治疗的判定标准:治愈28例(57.1%),显效11例(22.4%),有效7例(14.3%),无效3例(6.1%),总有效率达93.9%,未见明显不良反应。结论γ刀治疗TN总体安全有效,适用于临床推广。     

Linac Radiosurgery for Skull Base Meningiomas

Summary  Introduction. Skull base meningiomas present a difficult surgical challenge because of the high potential morbidity of radical surgical extirpation and their low potential for incapacitating symptomatology. The focal character of meningiomas makes stereotactic radiosurgery an attractive adjuvant treatment modality to resection. The purpose of this study was to evaluate the local control rates and complications in 56 patients with base of skull meningiomas undergoing radiosurgery.  Methods. Patients underwent radiosurgery using the dedicated stereotactic linear accelerator at the Brigham and Women's Hospital. Minimal peripheral doses of radiosurgery ranged from 12 to 18.5 Gy (mean 15 Gy). Doses were designed to conform to the frequently irregular tumor volumes using the X-Knife treatment planning system. Multiple isocenters were used when required to increase conformality of dose. For 36 patients (64%), radiosurgery was used as an adjunct to surgery; for 20 patients (36%) it was the primary treatment.  Results. Median followup was five years. Nineteen patients (34%) were improved clinically at follow-up; 32 (57%) were unchanged; and 5 patients (9%) developed new or worsened neurologic deficits. Serial imaging studies after radiosurgery showed a reduction in tumor volume in 23 patients (41%); 30 (54%) showed stable disease; 3 patients (5%) had tumors which increased in size (2 being outside the radiosurgery treatment site). The actuarial freedom from progression rate (defined as further tumor growth) was thus 95%, with a median imaging follow-up of 26 months (range, 6–66 months).  Although further follow-up is necessary, the results of this series clearly demonstrate that these lesions are feasible for treatment by modern radiosurgical techniques. Linac radiosurgery can stabilize skull base meningiomas, with decreased or unchanged tumor volumes on radiologic follow-up in approximately 95% of patients. Radiosurgery is a low-morbidity, effective technique as adjunct and sometimes primary treatment of small to moderate-sized meningiomas of the skull base.     

Gamma knife radiosurgical management of petroclival meningiomas results and indications

Summary ¶Background. Surgical treatment of petroclival meningiomas remains challenging. In order to refine indications for the use of stereotactic radiosurgery in the treatment of these tumours, we retrospectively evaluated our experience in this field. Methods. Thirty-two patients harboring a petroclival meningioma were treated consecutively using a Gamma knife between December 92 and June 1998. Eight patients underwent radiosurgery after one or more attempted surgical removals and 24 had radiosurgery as the primary treatment. The main symptoms before radiosurgery were cranial nerve palsies, including a sixth nerve deficit in 10 patients and a trigeminal nerve disturbance in 9. All patients underwent a conformal multi-isocentric treatment (mean isocenters number 8.8) and the dose delivered at the tumour margin ranged from 10 to 15Gy (mean dose 13Gy). Findings. The duration of follow-up varied from 24 to 118 months (mean clinical follow-up 56 months, mean radiological follow-up 52.6 months). All 32 patients survived. The tumour volume remained unchanged in 28 patients and decreased slightly in 4. Neurological status worsened permanently in 2 patients with a delayed hemiparesis due to focal pontine infarction. These complications were associated with large meningiomas with vascular involvement and ventral brainstem compression, and occurred at the very early stage of our experience. At last follow-up, preoperative fifth or sixth cranial nerve deficits had improved or recovered in 13 out of 19 patients and any delayed worsening or new cranial nerve deficits were not observed after radiosurgery. Conclusions. Stereotactic radiosurgery with a Gamma knife provides effective management of small to middle sized petroclival meningiomas and is an alternative to microsurgery. Careful selection of patients and use of major technical refinements should improve the safety of this treatment.Published online September 26, 2003     

The Role of Stereotactic Radiosurgery in the Management of Benign, Atypical, and Malignant Meningiomas

Stereotactic radiosurgery and fractionated Stereotactic radiotherapy (SR) offer precise localization of radiation dose (Gy) for the treatment of meningioma (M). For the multimodal treatment with preservation of function, SR is complementary to both microsurgery (S) and conventional external beam radiotherapy (XRT). The role of SR in the management of atypical and malignant meningiomas, however, remains unexplored. Fifty consecutive patients with meningioma: 18 males (60.1 +/– 2.3 years) and 32 females (56.9 +/– 2.2 years) (p = NS) received SR. Thirty-one patients had surgery 69.6 +/– 13.9 months (95% CI: 53.3–98.0) prior to SR. For patients having S, the incidence of atypical or malignant versus benign meningiomas (14 versus 17 patients) increased with age (p = 0.03). Twenty patients had XRT approximately 18 months prior to SR. For antecedent XRT, the range of doses was 3600–6400 cGy (median: 5040 cGy). Following failure of S and/or XRT, patients had SR. Compared to other series, the mean tumor volumes for SR were comparatively large: 9.8 +/– 1.3 cm³ (range 0.3–37.1 cm³). The median SR dose was 3500 cGy (range 540–5400 cGy) administered in seven fractions (range 1–30). Linear regression analysis showed a consistent method for fractionation: the number of administered fractions increased (p = 0.053) and the total dose increased (p = 0.054) with tumor size. During the interval for follow–up (17.9 +/– 2.9 months), one patient with malignant meningioma required surgery for progression 8 months after SR. In the remaining patients, post-SR MRIs showed control (unchanged or smaller tumor volume) regardless of histology. These results show that SR may provide control of M regardless of grade.     

Gamma knife radiosurgery of acoustic neurinomas

Summary  The authors report on their series of 40 patients with 41 acoustic neurinomas (ACNs), including one patient with bilateral acoustic neurinomas suffering from neurofibromatosis type 2 (NF II) who were treated with the gamma knife unit at their institution between August 1992 and October 1995.  Of these 41 tumours, 21 ACNs had been operated on before (1 to 4 times), 20 ACNs were exclusively treated by gamma knife radiosurgery (GKRS). The maximal axial tumour diameter ranged from 6 to 33 mm (median: 25 mm), the maximal transverse tumour diameter ranged from 7 mm to 36 mm (median: 16 mm). The dose distributed to the tumour margin was 10 to 17 Gy (median: 12 Gy) by enclosing the tumour with the 40% to 95% isodose line (median: 50% isodose line) and using 1 to 12 isocenters (median: 5 isocenters).  Central loss of contrast enhancement was observed in 78% of the patients within six to 12 months after radiosurgery. Thirty-two patients were observed over a minimum follow up period of at least 36 months, 9 patients were lost to follow up as they died of unrelated causes or refused further check-ups. Within the follow up period of up to seven years, magnetic resonance imaging (MRI) control scans revealed the tumour diameter stable or decreased in 29 cases and increased in three tumours. Of 14 patients with useful hearing before treatment, 9 patients were examined in addition to pure tone audiogramm by measurement of brainstem auditory evoked potentials (BAEPs) one to four years after radiosurgery. None of these patients showed a postoperative loss of the cochlea function. According to slight alterations of the cochlea function (cochlea summating action potential), pure tone audiometry of those patients revealed only slight changes of the hearing level (HL) within a maximum range of ±15 Decibel (dB). The hearing threshold improved in two, was stable in four and deteriorated in three patients, respectively.  We observed postradiosurgical aggravation of a pre-existing facial weakness in two out of 13 patients, a new occurrence of facial palsy was seen in two cases (four years after treatment), one of them was previously operated on and both suffered from cystic degeneration with mass effect. Tinnitus improved in six out of 13 patients, deteriorated in two and never appeared as a new permanent sequela. Trigeminal hypaesthesia did also not appear as a new permanent symptom, improved in three out of 9, and deteriorated in one out of 9 patients. Vertigo increased in six out of 23, was stable in 8 and decreased in nine out of 23 patients each. GKRS proves to be a safe and highly satisfactory therapeutical option or addition to open surgery, especially for radiologically verified regrowing residual ACNs, but also as primary treatment in selected patients. A high rate of tumour control can be achieved with an acceptable rate of neurological deficits.     

Successful Management of a Catecholamine-Secreting Glomus Jugulare Tumor with Radiosurgery Alone

Secretory glomus jugulare tumors are often resected surgically to control the systemic effects of the catecholamines they produce. This involves complex skull base surgery, which carries significant risks and frequent morbidity. Stereotactic radiosurgery (SRS) is a recently recognized treatment for glomus jugulare tumors, though little is known about its use in secretory tumors. Case Report A young fit patient with a catecholamine-secreting glomus jugulare tumor was treated with SRS alone and over the following 37 months her urinary catecholamine excretion fell to near normal levels, and serial magnetic resonance imaging (MRI) confirmed a reduction in tumor volume. Discussion Radiosurgery is an accepted treatment for glomus jugulare tumors and is now readily available to skull base surgeons. In this case a catecholamine-secreting tumor was successfully controlled with radiosurgery alone. Further research and long-term follow-up will determine the role of this treatment in the nonsurgical management of secreting glomus jugulare tumors.