Repeat Radiosurgery Research Articles

Repeat radiosurgery for cerebral AVMs

Purpose: Approximately 20 to 50 % of cAVMs treated by Radiosurgery (RS) fail to obliterate 2 to 5 years after a first Radiosurgery (RS1).Therefore the patients are not protected against the risks that were the very reasons for treatment. To eradicate the persisting nidus, a second RS (RS2) is an option for salvage treatment. We will evaluate this option in 39 pts initially treated by our group.

797 Outcomes after Repeat Radiosurgery for Trigeminal Neuralgia

797 Outcomes after Repeat Radiosurgery for Trigeminal Neuralgia

797 Outcomes after Repeat Radiosurgery for Trigeminal Neuralgia

Hasegawa, Toshinori MD; Spiro, Richard MD; Flickinger, John C. MD; Kondziolka, Douglas MD; Lunsford, L. Dade MD

脳動静脈奇形の塞栓術におけるｐｉｔｆａｌｌとその対策

As the embolization of AVMs is often an adjuvant therapy combined with surgical extirpation or radiosurgery, the goal is to optimize the outcome of the following procedure. As the natural history of AVMs predicts a relatively low rate of neurological injury, the combined therapeutic modalities should have a low complication rate. We report the perisurgical complications of 66 AVMs and discuss techniques to avoid complications. Of the 66 patients treated with endovascular embolization, 14 subsequently underwent surgical resection and 43 had radiosurgery. Four patients obtained total occlusion of their AVM by embolization alone and required no further treatment. In 48 patients, more than 70% of the nidus was occluded with embolization. We observed 3 permanent and 9 temporary complications. Four complications occurred immediately after embolization, due to overembolization or thromboembolism. Seven delayed complications occurred, possibly due to retrograde thrombosis or a chemical reaction to the glue. In 4 of the 14 cases without AVM obliteration following embolization and radiosurgery, meningeal feeders developed or recanalized after the treatment with absorbable particles. We recommend embolization prior to radiosurgery to treat all fistulous and meningeal feeders and packing of the nidus with non-absorbable embolic materials. In 10 cases, repeat embolization achieved further nidus reduction prior ro repeat radiosurgery. Intranidal aneurysms that pose a high risk of bleeding were also embolized. To avoid complications with embolization, the AVM angioarchitecture, hemodynamics and functional location should be well recognized. Complications can be reduced with preoperative functional imaging, superselective angiograms, appropriate selection of embolic materials, and appropriate selection of embolization targets. The priority of vessels to be embolized is dictated by the subsequent treatment. Agressive embolization of high-risk vessels or those that will cause abrupt hemodynamic changes should be avoided.

Repeat Radiosurgery For Incompletely Obliterated Arteriovenous Malformations

Repeat Radiosurgery For Incompletely Obliterated Arteriovenous Malformations

Wyburn–Mason Syndrome Variant Treated with Stereotactic Radiosurgery

Classical Wyburn–Mason syndrome consists of unilateral arteriovenous malformations affecting the retina, midbrain, and visual pathways in the brain, and the facial structures. An unusual case of Wyburn–Mason syndrome with bilateral manifestations and without retinal involvement is described. A 19-year-old girl presented at the age of 5 with a left hemiparesis and aphasia following intracerebral hemorrhage in the right internal capsule and basal ganglia. Angiography demonstrated left sylvian, right frontoparietal, and right thalamic arteriovenous malformations (AVMs). In addition to multiple intracranial AVMs, she had multiple telangiectatic lesions scattered over her body. Ophthalmological examination was normal except for left orbital bruit. Two years later, with moderate clinical improvement, she had proton beam radiosurgery for her multiple AVMs. Due to lack of beneficial effect, repeat radiosurgery with more appropriate dose is under consideration. A review of the literature revealed that our presenting case represents one of the few reported cases of atypical Wyburn–Mason syndrome with bilateral manifestations and without retinal involvement. To our knowledge, ours represent the first reported case for which radiosurgery had been offered as a treatment modality.

Multimodality treatment for large and critically located arteriovenous malformations.

To define the current status of the multimodality treatment for large and critically located arteriovenous malformations (AVMs), we have made a retrospective review of 54 consecutive patients with Spetzler-Martin grade IV and V AVMs. The size of nidus is larger than 3 cm in diameter in all cases. Initially, all but one were treated by nidus embolization with the aim of size reduction. Only one patient had complete nidus occlusion by embolization alone. In 52 patients, the obliteration rate of nidus volume averaged 60% after embolization. Ten patients underwent complete surgical resection of AVMs following embolization with no postoperative neurological deterioration. Thirty-one patients underwent stereotactic radiosurgery following embolization. At the time of this analysis, 30 patients underwent follow-up angiography 2-3 years after radiosurgery. The results of radiosurgery correlated well with the preradiosurgical AVM volume. Of 16 patients with small residual AVMs (< 10 cm3, a mean volume of 4.7 cm3), nine (56%) had complete obliteration, and six (38%) had near-total or subtotal obliteration by 3 years after radiosurgery. In contrast, of 14 patients with large residual AVMs (> or = 10 cm3, a mean volume of 17.9 cm3), only two (14%) had complete obliteration, and eight (57%) had near-total or subtotal obliteration. Repeat radiosurgery was performed for the patients with remaining AVMs at 3-year follow-up review. This study indicates that a certain number of large and critically located AVMs can be safely treated by either microsurgery or radiosurgery following a significant volume reduction by nidus embolization. The present data also suggest the need and possible role of repeat radiosurgery in improving complete obliteration rate of large difficult AVMs, since many of those AVMs have significantly responded to initial radiosurgery.

Repeat Stereotactic Radiosurgery of Arteriovenous Malformations: Factors Associated with Incomplete Obliteration

Second stereotactic radiosurgery procedures were required in 45 patients with arteriovenous malformations (AVMs) who initially had incomplete obliteration. Repeat radiosurgery was performed at a median of 39 months (range, 24-71 mo) after the first stage. The median AVM volume at the first procedure was 6.0 ml (range, 0.2-18.0 ml). Thirty-seven patients (82%) had AVMs of Spetzler-Martin Grades III through VI. A retrospective analysis revealed definite causes for incomplete obliteration after the first procedure in 33 patients (73%). Incomplete angiographic definition of the nidus was the most frequent factor (57%) associated with failed radiosurgery. Three patients (7%) had recanalization of the AVM nidus after prior embolization; four patients (9%) had incomplete nidus recognition, because AVM vessels were not visualized in the presence of a hematoma. "Radiobiological resistance" was another potential factor associated with failed radiosurgery in 17 patients (38%). Our current technique for volume determination and dose planning includes stereotactic magnetic resonance angiography, magnetic resonance imaging, and complete cerebral angiography (including superselective and external carotid artery injections, as indicated). Integrated multiplanar high-resolution imaging will likely increase the rate of AVM obliteration after stereotactic radiosurgery.

Tumour response and morphological changes of acoustic neurinomas after radiosurgery.

Twenty-seven of the 1560 patients treated by radiosurgery during the period 1984-1993 had acoustic neurinomas. Four cases were excluded from this study because they had a follow-up of less than 2 years. There were 24 neurinomas treated in 23 patients as one patient had a bilateral tumour. Seven patients underwent radiosurgery for a recurrent tumour (already operated on once or twice), while it was the first treatment for 16 patients. The tumour volume ranged from 1.99 cm3 to 18.30 cm3, and the patient follow-up was from 2 to 8 years. To determine the target on CT/NMR for linear accelerator stereotactic irradiation, the Greitz-Bergström non-invasive head fixation device was used. It was again adopted for subsequent serial imaging, and for repeat radiosurgery when necessary. The total peripheral tumour dose ranged from 12 to 45 Gy. In 9 patients there was a reduction in tumour volume varying from 39 to 100%, while 14 of the neurinomas appeared stable after an average follow-up of 3 years. In one patient there was an increase in size of the tumour. Variable morphological changes were present in 66% of the neurinomas treated. Radiosurgery is indicated as an alternative to microsurgery for inoperable patients and for those who refuse surgery, for recurrent tumours, and as a post-operative complementary treatment for partially removed tumours. A gradual approach to radiosurgery, depending on tumour response, allows a greater efficacy with minimal risk. In the present series no complications were observed. Hearing was preserved at almost the same level as that prior to radiosurgery in all patients.

The results of radiosurgical management of 139 single cerebral metastases.

Between March 1984 and June 1993, linac radiosurgery was performed in 139 patients for single brain metastases, using the non-invasive (Greitz-Bergström) head fixation system. This atraumatic system was utilized for subsequent stereotactic CT/NMR staging to obtain strictly comparable neuro-imaging. Thus, tumour response was evaluated precisely and radiosurgery repeated (straight after the diagnostic sitting), as needed. No hospitalization or anaesthesia was necessary. The 25 mm target was the maximum size to avoid the risk of radiation induced reactions. In metastases exceeding this limit single doses were directed at more than one target at the same session. Focusing upon single or multiple targets was facilitated by 3-D stereotactic NMR. The results after one single sitting were compared with those obtained after staged sittings in the same patients. Radiosurgery achieved disappearance or shrinkage of the metastasis with resolution of the oedema and mid-line shift in 86% of the 139 patients treated. In 47% of them, however, the success was the result of repeat radiosurgery and staged sittings. The non-invasive procedure is the keystone to optimize the radiosurgical results.

Stereotactic radiosurgery for pituitary adenomas: imaging, visual and endocrine results.

To determine the endocrine, ophthalmologic, and tumor growth control responses after stereotactic radiosurgery using the gamma unit, we reviewed our experience in 35 patients with pituitary adenomas. Twenty-four females and 11 males (mean age 47 years, range 9-81 years) had radiosurgery with average follow-up of 26 months (range 6-60 months). Most patients were refractory to surgical removal. Fifteen patients had Cushing's disease. Prior transsphenoidal resection was performed in 14 patients (6 had two prior operations), fractionated radiotherapy in 3, and adrenalectomy in 2. In 11 evaluable patients, the hormone response was normalized in 8, decreased in 2 and increased in 1. Five patients remained on cortisol suppression. Of 12 patients with imaging follow-up, 4 had decreased tumor size, 6 had no change, and 2 had an increase; these 2 patients underwent subsequent surgery. Ten patients had acromegaly, and 6 had undergone prior surgery. Of 8 evaluable patients, growth hormone secretion has normalized in 3, decreased in 3, and increased in 2. Six tumors decreased in size, and 2 were unchanged. One patient had repeat resection 21 months after radiosurgery and one patient underwent repeat radiosurgery. Ten patients had non-secreting adenomas; all 10 had prior operations (1-4 operations, 6 underwent frontal craniotomy) and 5 had undergone fractionated radiotherapy. Eight patients had panhypopituitarism prior to radiosurgery. Four tumors decreased in size and 6 were without change.(ABSTRACT TRUNCATED AT 250 WORDS)