Dominant A1 Direction as an Additional Factor for Deciding Surgical Approach for A1 Bifurcation Aneurysms.

BACKGROUND AND OBJECTIVE: Clipping of aneurysms located in the anterior communicating artery (AcomA) is considered a critical surgical procedure for neurosurgeons worldwide because of the complexity of the surgical area. The present study was conducted to discuss the importance of the geometric curvatures and the direction of the dominant A1 artery and their impact on aneurysmal growth direction and choice of side selection of the pterional surgical approach side. METHODS: The present study enrolled 183 patients with ruptured AcomA-located aneurysms. The aneurysms were all treated surgically through a pterional approach. Because of multiple dominant A1 directions, we divided the artery into 2 segments, and based on the second segment direction, we categorized the patients into ascending A1, descending A1, and horizontal A1 groups. The ascending group includes the superiorly projecting aneurysms, whereas the horizontal and descending groups include the anteriorly and inferiorly projecting aneurysms, respectively. A contralateral pterional approach to the dominant A1 was chosen for aneurysms with an ascending artery. However, the ipsilateral pterional approach was conducted in the horizontal and descending A1 dominant groups. RESULTS: The aneurysmal growth projection axis always follows the direction of the second dominant A1 segment. Full neck control with satisfactory inspection of perforators was achieved through the contralateral approach in most cases of an ascending A1, especially if ipsilateral A2 was posterior to the neck. The A1 segment can be satisfactorily seen from the contralateral exposure before the aneurysmal neck is exposed in ascending A1 geometries. CONCLUSIONS: A1 direction is an important additional factor that is to be considered for side selection when deciding pterional exposure of A1 bifurcation aneurysms. Accessing the contralateral dominant ascending A1 has better visualization of the neck than entering from an ipsilateral approach, especially if the ipsilateral A2 was posterior to the neck.

Hypofractionated Radiation Therapy For Diffuse Intrinsic Pontine Glioma: A Noninferiority Randomized Study Including 253 Children.

PURPOSE: Pediatric diffuse intrinsic pontine glioma is an orphen disease. This study aimed to confirm the noninferiority of hypofractionated (HF) radiation therapy. Identification of the prognostic factors that determine the overall survival (OS) and progression-free survival (PFS) was the secondary objective. METHODS AND MATERIALS: We randomized 253 patients into 3 arms of radiation therapy regimens: HF1, receiving 39 Gy in 13 fractions; HF2, receiving 45 Gy in 15 fractions; and conventional fractionation (CF), receiving 54 Gy in 30 fractions. The OS and PFS were calculated using Kaplan-Meier methods, and the noninferiority was estimated against the CF arm. RESULTS: The median OS for the HF1, HF2, and CF were 9.6, 8.2, and 8.7 months, respectively. The 1-, 1.5-, and 2-year OS were 34.6%, 17.9%, and 10.7% for HF1; 26.2%, 13.1%, and 4.8% for HF2; and 25.3%, 12.1%, and 8.4% for CF, respectively (P = .3). The hazard ratio was 0.776 and 1.124 for HF1 and HF2, respectively. Considering the noninferiority margin (Δ) of 15% and a power of 90%, the lower inferiority confidence interval for HF1 was -14.34% and for HF2 it was 11.37% (both below Δ), confirming its noninferiority at 18-months OS. Younger patients (2-5 years of age) had better median OS in the whole cohort (11.6 months), HF1 (13.5), and CF (12.1) but not HF2 (6.2) (P = .003). Furthermore, the OS rates at 1, 1.5, and 2 years for children 2 to 5 years of age in the HF2 arm were lower than those in the HF1 and CF arms. However, similar acute and late side effects were reported in the 3 arms. CONCLUSIONS: Two hypofractionated radiation therapy proved to be noninferior to conventional fractionation. Young age (2-5 years) is the only prognostic factor determining both OS and PFS. The young age superiority was lost with a higher hypofractionated radiation therapy dose, necessitating more caution in applying 45 Gy in 15 fractions in younger children (2-5 years of age).