Analysis of Evolution of Hydrocephalus in Posterior Fossa Tumors and Validation Study of the Modified Canadian Preoperative Prediction Rule for Hydrocephalus in Children and Frankfurt Grading System for Prediction of Cerebrospinal Fluid Diversion in Adults with Posterior Fossa Tumors.

OBJECTIVE: We sought to analyze the evolution of hydrocephalus and enumerate its predictive factors in posterior fossa tumors in children and adults. We also validated the modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) and Frankfurt grading systems as tools to predict cerebrospinal fluid (CSF) diversion in children and adults, respectively. METHODS: A retrospective review of patients with posterior fossa tumors operated between 2012 and 2019 was performed. Clinical, radiologic, and operative data were obtained. Validation was performed for both scores via receiver operating characteristic (ROC) curves and evaluation of the area under the curve (AUC). RESULTS: We included 116 children and 343 adults in the study. Of the adults, 141 patients had intraaxial tumors and 172 had extraaxial tumors. The insertion of external ventricular drain (EVD), its duration, papilledema was noted to have significant influence on the need for permanent CSF diversion (P < 0.05) in children. The ROC for mCPPRH score was 0.659 (0.501-0.816), Age- 0.496 (0.334-0.658) and Evans index- 0.788 (0.654-0.922). In adults- Intraaxial tumours Age, Frankfurt score, duration of EVD, Diagnosis, Extent of resection and periventricular capping significant predictors and ROC age AUC 0.300 (0.193-0.407), Evans index 0.939 (0.888-0.990), and Frankfurt score 0.908 (0.853-0.964) (P < 0.05), whereas in extraaxial tumors Frankfurt grading, sex, duration of EVD, presence of perilesional edema and extent of resection (P < 0.05) ROC age AUC 0.439 (0.344-0.534), Evans index 0.941 (0.906-0.977), and Frankfurt score 0.847 (0.782-0.912). CONCLUSIONS: This is the first external validation study for the 2 predictive systems in use. mCPPRH demonstrated poor predictive accuracy, and Frankfurt grading system demonstrated good accuracy. EVD insertion and its duration was significantly predictive of the need for permanent CSF diversion.

The Jai knot technique for deep microvascular surgery.

BACKGROUND: Microvascular surgery requires fine finger movements with stabilised hands for successful anastomosis. Limited space in deeper locations, such as the interhemispheric fissure, increases the difficulty in placing the knots during microvascular suturing. METHODS: This note describes a novel technique of constructing reef knots. The technique reduces the excursions of the instrument tips while knotting. CONCLUSIONS: Using this knotting technique in deep microvascular suturing improves the ergonomic ease and stability of knots, while working in deep locations through narrow corridors.

Strategic tunnelling of superficial temporal artery during bypass surgery for moyamoya disease.

BACKGROUND: The superficial temporal artery to middle cerebral artery bypass remains the favoured direct technique of cerebral revascularization in moyamoya angiopathy. We describe a novel technique of tunnelling the superficial temporal artery through the temporalis muscle. METHODS: The temporalis muscle is raised as a flap off the temporal bone. A triangular window is created on the temporalis fascia, and a tunnel is created for the superficial temporal artery to pass through the muscle belly. CONCLUSION: This innovative technique allows passage of the superficial temporal artery to the brain without kink or compression ensuring good bypass function and improves long-term patency.

The mechanobiological theory: a unifying hypothesis on the pathogenesis of moyamoya disease based on a systematic review.

OBJECTIVE: Moyamoya angiopathy (MMA) affects the distal internal carotid artery and is designated as moyamoya disease (MMD) when predisposing conditions are absent, or moyamoya syndrome (MMS) when it occurs secondary to other causes. The authors aimed to investigate the reason for this anatomical site predilection of MMA. There is compelling evidence to suggest that MMA is a phenomenon that occurs due to stereotyped mechanobiological processes. Literature regarding MMD and MMS was systematically reviewed to decipher a common pattern relating to the development of MMA. METHODS: A systematic review was conducted to understand the pathogenesis of MMA in accordance with PRISMA guidelines. PubMed MEDLINE and Scopus were searched using "moyamoya" and "pathogenesis" as common keywords and specific keywords related to six identified key factors. Additionally, a literature search was performed for MMS using "moyamoya" and "pathogenesis" combined with reported associations. A progressive search of the literature was also performed using the keywords "matrix metalloprotease," "tissue inhibitor of matrix metalloprotease," "endothelial cell," "smooth muscle cell," "cytokines," "endothelin," and "transforming growth factor" to infer the missing links in molecular pathogenesis of MMA. Studies conforming to the inclusion criteria were reviewed. RESULTS: The literature search yielded 44 published articles on MMD by using keywords classified under the six key factors, namely arterial tortuosity, vascular angles, wall shear stress, molecular factors, blood rheology/viscosity, and blood vessel wall strength, and 477 published articles on MMS associations. Information obtained from 51 articles that matched the inclusion criteria and additional information derived from the progressive search mentioned above were used to connect the key factors to derive a network pattern of pathogenesis. CONCLUSIONS: Based on the available literature, the authors have proposed a unifying theory for the pathogenesis of MMA. The moyamoya phenomenon appears to be the culmination of an interplay of vascular anatomy, hemodynamics, rheology, blood vessel wall strength, and a plethora of intricately linked mechanobiological molecular mediators that ultimately results in the mechanical process of occlusion of the blood vessel, stimulating angiogenesis and collateral blood supply in an attempt to perfuse the compromised brain.

Superficial Temporal Artery Extended Interposition Graft to Anterior Cerebral Artery Bypass for the Treatment of a Large Fusiform Distal Anterior Cerebral Artery Aneurysm: 2-Dimensional Operative Video.

Fusiform aneurysms of the distal anterior cerebral artery (DACA) are infrequent. Clip reconstruction and sequential progressive clipping have been described in the management of giant thrombosed DACA aneurysms.1,2 Customized revascularization with bypass, side-to-side anastomosis, and trapping of the aneurysmal segment have also been performed for treating DACA aneurysms.3-12 We present a 2-dimensional operative video of superficial temporal artery (STA) to distal anterior cerebral artery bypass, followed by trapping of the aneurysm-bearing segment. A 57-yr-old lady presented with a large ruptured subcallosal fusiform DACA aneurysm (WFNS grade 1, Fisher grade 1). Angiography revealed a 1.3 × 0.9 cm fusiform aneurysm in the DACA. Informed consent was secured from the patient and her family for the surgery and permission was obtained for the publication of the patient's image/surgical video. The frontal and parietal branches of the STA were dissected. The parietal branch was explanted and used as a free interposition graft between the frontal branch (end-to-end anastomosis) and calloso-marginal artery (end-to-side anastomosis). After confirming blood flow through the bypass using Doppler, the aneurysm was trapped and excised. The patient had an uneventful recovery. Her postoperative computed tomography (CT) head revealed no evidence of neurological insult. The patency of the bypass conduit and the complete removal of the aneurysm were confirmed using a digital subtraction angiogram. Histopathological examination revealed an eccentric atheromatous plaque with a lipid core. There was no evidence of intraplaque hemorrhage. This extended STA graft utilizing the frontal and parietal branches of the STA, and its implantation into the distal ACA, offers a novel bypass strategy for tackling fusiform aneurysms of the DACA. Anastomosis to the calloso-marginal artery ensured perfusion of the ACA territory through the pericallosal artery during temporary occlusion.

Cyanosis and Clipping: Noninfectious Aneurysm in a Patient with 22q11.2 Deletion Syndrome.

Noninfectious cerebral aneurysms are rare in patients with congenital cyanotic heart disease. We present a patient with DiGeorge/velocardiofacial syndrome with a complex congenital cyanotic heart disease with a ruptured anterior communicating artery aneurysm. The 10-year-old child was managed by surgical clipping of the aneurysm. Surgical challenges included prominent veins in the Sylvian fissure, difficulty in differentiating arterial and venous bleed, and anesthetic risks. The patient recovered without any neurological deficits. This is the first report of a patient with 22q11.2 deletion syndrome, with a noninfectious cerebral aneurysm.