Tag: Gamma knife radiosurgery

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Results for a Series of 697 Arteriovenous Malformations Treated by Gamma Knife

AVM frontal

Neurosurgery 75:568–583, 2014

Stereotactic radiosurgery (RS) is an effective tool in treating brain arteriovenous malformations (AVMs). Careful study of AVM angiographic characteristics may improve results.

OBJECTIVE: To report the long-term outcomes of Gamma Knife RS (GKRS) in brain AVMs, focusing on how the angioarchitectural and hemodynamic parameters of AVMs affect the post-RS results.

METHODS: This was a retrospective, longitudinal study of 697 consecutive GKRS treatments of brain AVMs in 662 patients performed at a single center between 1993 and 2005. The mean age of the patients was 37 years; the median AVM volume was 3.6 cm3; and the mean follow-up was 11 years. Forty-five percent of patients presented with intracranial hemorrhage; 44% underwent embolization; and 7% had multiple RSs. AVM characteristics in the RS-planning angiograms were analyzed, and their relationship to the post-RS obliteration rate was determined by univariate and multivariate analyses.

RESULTS: The obliteration rate after a single RS was 69.3%; after multiple RS, it was 75%. Positive predictors of obliteration included compact nidus (odds ratio = 3.16; 95% confidence interval, 1.92-5.22), undilated feeders (odds ratio = 0.36; 95% confidence interval, 0.23-0.57), smaller AVM volume (odds ratio = 0.95; 95% confidence interval, 0.92-0.99), and higher marginal dose (odds ratio = 1.16; 95% confidence interval, 1.06-1.27). Improvement or clinical stability was observed in 89.3% of patients; postprocedural bleeding was noted in 6.1%; and clinical worsening attributable to RS was seen in 3.8%. The annual risk of hemorrhage in the 4 years after RS was 1.2%.

CONCLUSION: GKRS yielded a good long-term clinical outcome in most patients. Certain angiographic features of brain AVMs such as a well-defined nidus and undilated feeder arteries contribute to AVM occlusion by RS. GKRS can be regarded as the treatment of choice for AVMs <6 cm3, even after bleeding.

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Computational Fractal-Based Analysis of Brain Arteriovenous Malformation Angioarchitecture

Computational Fractal-Based Analysis of Brain Arteriovenous Malformation Angioarchitecture

Neurosurgery 75:72–79, 2014

Neuroimaging is the gold standard for diagnosis and follow-up of brain arteriovenous malformations (bAVMs), but no objective parameter has been validated for the assessment of the nidus angioarchitecture and for prognostication following treatment. The fractal dimension (FD), which is a mathematical parameter able to quantify the space-filling properties and roughness of natural objects, may be useful in quantifying the geometrical complexity of bAVMs nidus.

OBJECTIVE: To propose FD as a neuroimaging biomarker of the nidus angioarchitecture, which might be related to radiosurgical outcome.

METHODS: We retrospectively analyzed 54 patients who had undergone stereotactic radiosurgery for the treatment of bAVMs. The quantification of the geometric complexity of the vessels forming the nidus, imaged in magnetic resonance imaging, was assessed by means of the box-counting method to obtain the fractal dimension.

RESULTS: FD was found to be significantly associated with the size (P = .03) and volume (P , .001) of the nidus, in addition to several angioarchitectural parameters. A nonsignificant association between clinical outcome and FD was observed (area under the curve, 0.637 [95% confidence interval, 0.49-0.79]), indicative of a potential inverse relationship between FD and bAVM obliteration.

CONCLUSION: In our exploratory methodological research, we showed that the FD is an objective computer-aided parameter for quantifying the geometrical complexity and roughness of the bAVM nidus. The results suggest that more complex bAVM angioarchitecture, having higher FD values, might be related to decreased response to radiosurgery and that the FD of the bAVM nidus could be used as a morphometric neuroimaging biomarker.

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Vestibular Schwannoma: Surgery or Gamma-Knife radiosurgery?. A prospective, non-randomized study

Neurosurgery 64:654–663, 2009 DOI: 10.1227/01.NEU.0000340684.60443.55

OBJECTIVE: To conduct a prospective, open, nonrandomized study of treatment- associated morbidity in patients undergoing microsurgery or gamma knife radiosurgery (GKRS) for vestibular schwannomas.

METHODS: Ninety- one patients with vestibular schwannomas with a maximum tumor diameter of 25 mm in the cerebellopontine angle were treated according to a prospective protocol either by GKRS (63 patients) or open microsurgery (28 patients) using the suboccipital approach. Primary end points included hearing function, according to the Gardner- Robertson scale, and facial nerve function, according to the House- Brackmann scale at 2 years. Clinical data included a balance platform test, score for tinnitus and vertigo using a visual analog scale, and working ability. Patients responded to the qualityof- life questionnaires Short- Form 36 and Glasgow Benefit Inventory.

RESULTS: Three elderly GKRS patients withdrew; all remaining patients were followed for 2 years. Both primary end points were highly significant in favor of GKRS (P<0.001). Evidence of reduced facial nerve function (House- Brackmann grade 2 or poorer) at 2 years was found in 13 of 28 open microsurgery patients and 1 of 60 GKRS patients. Thirteen of 28 patients who underwent surgery had serviceable hearing (Gardner- Robertson grade A or B) preoperatively, but none had serviceable hearing postoperatively. Twentyfive of 60 GKRS patients had serviceable hearing before treatment, and 17 (68%) of them had serviceable hearing 2 years after treatment. The tinnitus and vertigo visual analog scale score, as well as balance platform tests, did not change significantly after treatment, and working status did not differ between the groups at 2 years. Quality of life was significantly better in the GKRS group at 2 years, based on the Glasgow Benefit Inventory questionnaire. One GKRS patient required operative treatment within the 2-year study period.

CONCLUSION: This is the second prospective study to demonstrate better facial nerve and hearing outcomes from GKRS than from open surgery for small- and medium- sized vestibular schwannomas.

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Gamma knife radiosurgery for the treatment of glomus jugulare tumors

Journal of Neuro-Oncology. doi:10.1007/s11060-009-0002-6

The treatment of glomus jugulare tumors represents a challenge for the neurosurgeon, since they invade major vessels and compress critical cranial nerves, resulting in significant morbidity from tumor resection. Among alternative and complementary treatment options, gamma knife radiosurgery is a less invasive procedure and may provide better protection of vital structures. This study aimed to evaluate the efficacy and long-term outcomes of gamma knife surgery in the treatment of these tumors in a large series with the longest follow-up period compared with previous reports. A total of 18 patients with glomus jugulare tumors that underwent gamma knife radiosurgery (GKS) were included. Eleven patients had a history of previous microsurgical treatment. The mean marginal radiation dose was 15.6 Gy (median 15 Gy, range 13–20 Gy). Patients were followed for a mean period of 52.7 months (median 41.5 months); the effect of gamma knife radiosurgery was evaluated using magnetic resonance (MR) images. Based on the last MR images, tumor control could be achieved in 17 out of 18 patients (94.4%). No complications such as radiation-induced peritumoral edema or radiation necrosis occurred. Neurological follow-up examinations revealed improved clinical status in ten patients (55.6%), stable neurological status in seven (38.9%), and deterioration in one patient (5.5%). At the last visit, 17 out of 18 patients were alive. Our results indicate that stereotactic radiosurgery is an effective and safe treatment modality in the management of glomus jugulare tumors, particularly for residual or previously untreated small tumors.

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