Suture techniques and patch materials using an in-vitro model for watertight closure of in-utero spina bifida repair

Purpose: Despite proven benefits of in-utero spina bifida (SB) repair, >= 30% of children at birth have Chiari II malformation or cerebrospinal fluid (CSF) leakage from the repair site. Our study's purpose was to determine CSF pressures in the myelomeningocele sac during mid-gestation in order to design an in-vitro model for evaluating different surgical methods used for watertight closure during in-utero SB repair. Methods: CSF pressures were measured during in-utero SB repair at mid-gestation. An in-vitro chicken thigh model, simulating fetal tissue, tested watertight closure when attached to the base of a water column. Primary closure methods were evaluated using defect sizes of 20 x 3 mm for minimal traction or 20 x 8 mm for moderate traction. Additionally, 3 common in-utero repair patches were compared using 15 x 15 mm defects. Results: Using 6-12.5 cm pre-determined CSF pressures, 165 in-vitro experiments were performed. Regardless of methodology we found that in 66 primary-based closures that minimal versus moderate wound edge traction provided better seals. The locking method was superior to the non-locking technique for watertight closure in 99 patch-based closures. Conclusions: Minimal wound edge traction was best for primary closures, and locking sutures ideal for patchbased closures, however surgical techniques should be individualized to improve upon clinical outcomes. (C) 2019 Elsevier Inc. All rights reserved.