Biomechanical Impact of Partitioning Position and Angle on Post-SPGJ Gastric Emptying

Stomach-partitioning gastrojejunostomy (SPGJ) improves gastric-outlet obstruction outcomes, yet its biomechanical basis and geometric optimization remain unclear. Patient computed tomography (CT) data were used to reconstruct realistic SPGJ models. Computational fluid dynamics combined with a discrete phase model quantified velocity, wall pressure, particle-retention time, and velocity under systematic variations of partitioning position (distal, mid, and proximal), partitioning angle (5°, 15°, and 25°; left- or right-sided), and incision angle (60°, 75°, and 90°). Distal partitioning produced the lowest pressure drop and fastest emptying, whereas proximal partitioning channeled high-speed flow toward the pylorus and prolonged retention. A ∼15° partitioning angle balanced flow restriction and clearance; extreme unilateral angles either increased particle stasis (left-side) or slowed emptying despite reduced reflux (right-side). A vertical incision (90°) further decreased pressure losses and shortened mean retention relative to oblique cuts. SPGJ biomechanics are highly geometry-sensitive. Distal placement, a 15° partitioning angle, and a near-vertical incision collectively optimize flow, reduce lesion contact, and accelerate gastric emptying, providing quantitative guidance for patient-specific SPGJ design.