Hypo-fractionated Gamma Knife Radiosurgery for Intra-cranial Pathologies: A Single-Center Prospective Analysis of Feasibility, Safety, Efficacy, and Complication Profile.

Background: Single-session stereotactic radiosurgery (SRS) is a proven and effective treatment modality for various benign, malignant, and functional intra-cranial pathologies. In certain situations, single-fraction SRS is limited because of lesion size and location. Hypo-fractionated gamma knife radiosurgery (hfGKRS) is an alternative approach for such unconventional indications. Objective: To evaluate the feasibility, efficacy, safety, and complication profile of hfGKRS with evaluation of different fractionation schemes and dosing patterns. Methodology: The authors prospectively evaluated 202 patients treated with frame-based hfGKRS over a 9-year period. GKRS was administered fractionated because of either a large volume (>14 cc) or an inability to spare neighboring organs at risk from permissible radiation in single-session GKRS. The inter-fraction interval was kept at 24 hours, and the dose calculation was performed with linear quadratic equations. Patients with more than 3 years of clinical and radiological follow-up were included in prospective analysis. At pre-decided follow-up criteria, treatment effects and side effects were documented on objective scales. Results: A total of 169/202 patients met inclusion criteria. 41% patients received treatment in three fractions, whereas 59% received two-fraction GKRS. Two patients of giant cavernous sinus hemangiomas were treated with 5 Gy in the five-fraction regimen. In patients with more than 3 years of follow-up, the obliteration rate was 88% for complex arteriovenous malformations (AVMs) treated with hfGKRS because of eloquent locations, whereas it was 62% for Spetzler-Martin grade 4-5 AVMs. For non-AVM pathologies (meningiomas, schwannomas, pituitary adenomas, paragangliomas, hypothalamic hamartomas, etc.), the 5-year progression free survival was 95%. Tumor failure was noted in 0.05% patient population. Radiation necrosis developed in 8.1% patients, and radiation-induced brain edema developed in 12% patients. It was resistant to treatment in 4% patients. No patient developed radiation-induced malignancy. Hypo-fractionation did not provide any hearing improvement in giant vestibular schwannomas. Conclusion: hfGKRS is a valuable standalone treatment option for candidates unsuitable for single-session GKRS. The dosing parameters need to be tailored as per the pathology and neighboring structures. It provides comparable results to single-session GKRS with an acceptable safety and complication profile.

Effect of Age, Stage, and Type of Surgical Revascularization on Clinical and Angiographic Outcome in Moyamoya Disease - Experience from a Case Series of 175 Revascularization Procedures.

Background: There is dearth of literature on impact of age - pediatric versus adult, Suzuki staging - early versus late, and revascularization type - indirect versus direct on clinical and angiographic outcome in moyamoya disease (MMD). Hence, we intend to comprehensively evaluate factors influencing outcome in MMD following surgical revascularization. Methods: MMD patients operated at our institute from January 2011 to August 2018 were followed for an average 24 months. Primary outcomes were modified Rankin score (mRS) and stroke risk reduction. Secondary outcome was angiographic outcome score (AOS). Results: A total of 133 patients including 37.6% adults (>18 years; n = 50) underwent 175 revascularizations - 89 direct (DR) and 86 indirect (IR) subgroups. Mean mRS scores improved in pediatric DR (P < 0.001), IR (P < 0.001), adult IR (P = 0.10), and DR (P = 0.25) subgroups. Recurrent stroke rate was similar in pediatric-DR (2.7%) and IR (7.6%, P = 0.61), and adult-DR (0%) and IR (4.1%) subgroups (P = 1.00). AOS scores improved in pediatric DR (P = 0.002) and IR (P = 0.01), and adult-DR (P = 0.02) and IR (P = 0.06) subgroups. Late-stage MMD (Suzuki IV-VI) showed better improvement in mRS scores than early-stage-Suzuki (I-III; P < 0.001). Recurrent stroke rates were similar (P = 0.26) and AOS scores improved significantly in early- and late-stage MMD (P < 0.001). Conclusions: In pediatrics, clinical and angiographic outcome significantly improved after revascularization procedure, and in adults, angiographic improvement was more evident than clinical recovery. Late-stage Suzuki MMD patients demonstrated significantly better clinical improvement than early stage. The angiographic improvement was equivalent to early stage, irrespective of age and type of revascularization.

Sequential aneurysms with incidental persistent primitive trigeminal artery: Is this association purely coincidental? A case study and review of the literature in search for a pathobiological mechanism.

Background: The appearance of sequential bilateral aneurysms in patients with persistent primitive trigeminal artery (PTA) is not described in the literature. No clear guidelines on screening and follow-up of patients with incidental PTAs for the detection of associated lesions have been established. Case Description: A 55-year-old lady presented with occasional headaches. Detailed evaluation showed a left ophthalmic segment internal carotid artery (ICA) aneurysm measuring (11.2 × 5.5) mm. A bovine aortic arch configuration (type III) and a persistent left PTA were identified. A pipeline flex flow diverter was placed and aneurysm was coiled. Follow-up angiography after 6 months showed a completely occluded aneurysm with preserved PTA and a new aneurysm in the right ICA ophthalmic segment measuring 3.5 × 1.5 mm. It was followed up serially with angiography which revealed significant increase in 6 months. The base measured 5.4 mm and two blebs 3.1 mm and 2.5 mm had appeared on the dome. A SUPRASS flow diverter was placed across this aneurysm. Serial follow-up showed complete occlusion of the left aneurysm and significant reduction in filling of the right aneurysm. A review of the literature identified 34 cases of incidental PTAs associated with 50 aneurysms with increased prevalence of anterior circulation aneurysms in patients with incidental PTA. Conclusion: Sequential angiography of a patient with incidental PTA and an ICA aneurysm shows presence of a new aneurysm in contralateral circulation and its progression in size and morphology. Detailed large-scale studies are needed to assess the impact of incidental PTA on aneurysm development and management.

Insurance and Flow-Alteration Superficial Temporal Artery to Middle Cerebral Artery (STA-MCA) Bypass in Management of Complex Anterior Intracranial Circulation Aneurysms in Postendovascular Era.

BACKGROUND: Optimal management of complex anterior circulation aneurysms is an enigmatic challenge because of frequent involvement of major vessel bifurcation, choroidal vessels, and lenticulostriate/thalamostriate perforators. Cerebral ischemia associated with prolonged clipping time is a major concern pertinent to their surgical management, especially in patients with poor cross-flow. To circumvent this hurdle, single/double-barrel low-flow superficial temporal artery (STA) to middle cerebral artery (M3/M4-MCA) can be performed, which can maintain distal cerebral perfusion while facilitating safe clip reconstruction of complex MCA and supraclinoidal internal carotid artery (ICA) aneurysms involving ICA bifurcation or supraclinoidal ICA aneurysms with poor cross-circulation-insurance bypass, as well as supplement/alter blood flow after MCA aneurysm trapping-flow-alteration bypass. METHODS: A retrospective chart review of consecutive neurosurgical patients operated over 2 years at this center was performed. Patients with complex MCA and ICA aneurysms who were treated with STA-MCA bypass were included. The clinical profile, pre- and postoperative images, intraoperative imaging, and patient outcomes were recorded. Surgical reconstruction of aneurysm was the treatment of choice due to involvement of choroidal/thalamostriate perforators, MCA/ICA bifurcation, complex aneurysm morphology, or dissecting/thrombosed nature of aneurysm. STA-MCA low-flow bypass was performed using M3/M4 segment of MCA as the recipient in anticipation of prolonged temporary clipping time on M1-MCA, supraclinoidal ICA aneurysms with suspected ICA terminus involvement, or need for possible trapping of fusiform MCA aneurysm. The saccular/fusiform part of aneurysm was clip reconstructed and the partially thrombosed dissecting segment was opened for thrombectomy and trapped using proximal and distal clips after good patency of bypass was confirmed. The distal MCA flow was restored adequately and confirmed intraoperatively using indocyanine green angiography and micro-Doppler ultrasonography. RESULTS: MCA (n = 4) and supraclinoid-ICA (n = 1) aneurysms were managed successfully using this strategy, which involved 6 STA-MCA bypass procedures (insurance and flow-alteration bypass, 3 each). Postoperative check angiograms demonstrated patent bypass in all 5 patients. Four patients had favorable outcome (modified Rankin Scale score 0/1); one had recovering hemiparesis and aphasia (modified Rankin Scale score 4). CONCLUSIONS: This series highlights the surgical strategy and safety for successfully managing complex MCA and ICA aneurysms using low-flow STA-MCA revascularization procedures.

Measuring glioma volumes: A comparison of linear measurement based formulae with the manual image segmentation technique.

CONTEXT: Gliomas are irregular in shape unlike benign brain tumors like meningiomas or schwannomas. Simplifying assumptions about glioma geometry are therefore more likely to lead to wrong calculations of glioma volumes than for other tumors. AIMS: We compared simple linear measurement.based techniques of measuring glioma volume with manual region of interest.based image segmentation and to assess concordance. SETTINGS AND DESIGN: This study was a retrospective radiology archive-based study. SUBJECTS AND METHODS: The volumes of gliomas were measured by two assessors using five different techniques - manual image segmentation and four linear measurement-based formulae, which included the formulae for the volume of a sphere, cylinder, ellipsoid and its simplification v = abc/2. STATISTICAL ANALYSIS USED: Intra-ssessor concordance was evaluated using mean vs. difference. (Bland-Altman) plots and raw agreement indices. Inter-rater agreement was assessed by calculating the intra-class correlation coefficient for each technique. RESULTS: The best inter.rater concordance was for volume measured by manual segmentation. The tumor volumes measured using the formulae for volume of a sphere and cylinder had poor agreement with the planimetric volume and low inter.rater concordance. The formula for volume of an ellipsoid and its simplification had good agreement with the manual planimetric volume and had good inter.rater concordance. However, for larger tumors, the agreement with planimetric volume was poorer. CONCLUSIONS: Manual region of interest-based image segmentation is the standard technique for measuring glioma volumes. For routine clinical use, the simple formula v = abc/2 (or the formula for volume of an ellipsoid) could be used as alternatives.