Preoperative BOTOX® Injection for Large Ventral Hernia Repair

Background and Rationale: Massive ventral hernias (pre-op axial width ≥15 cm and/or Tanaka volume ratio \>25%) seldom achieve primary fascial closure (PFC) and are associated with higher respiratory morbidity, intensive care unit (ICU) utilization, post-operative pain, hospital length of stay (LOS), cost, and recurrence. Spasticity/fibrosis of the external oblique-internal oblique-transversus abdominis (EO/IO/TA) complex likely limits lateral abdominal wall compliance and impedes midline medialization. Pre-operative, image-guided onabotulinumtoxinA (BOTOX®) has been proposed to elongate the lateral wall, enlarge the functional abdominal domain, reduce closure pressures, and thereby increase the primary fascial closure (PFC) rate. Prior institutional data show \~77% PFC in this population without pre-op toxin, whereas retrospective series suggest \~95% with toxin utilization, motivating a definitive randomized trial. Design: Single-center, randomized, double-blind, placebo-controlled superiority trial. Randomization uses pre-generated block allocation (statistician-generated). Analyses will be intention-to-treat (ITT), with a parallel per-protocol (PP) analyses limited to participants who receive the assigned injection and undergo AWR within 21-48 days post-injection. A single interim analysis is planned at 50% completion of primary endpoint. Intention-to-treat (ITT) is primary method of analysis; however, a per-protocol (PP) analysis will also be conducted as this supports causal inference among adherent participants. An independent DMC will review interim results and advise on continuation/early stopping. Interventions: Fully described in 'Arms and Interventions' section. Participants will either receive image-guided injections of BOTOX® at six sites on the lateral abdominal wall (three sites per side) with a total of 300 units give (2 u / cc concentration; 25 cc at each site); or, participants will receive the same volume of a 0.9% saline solution (25 cc at each site). End Points and Outcomes: Fully described in the 'Outcomes Measures' section. Primary endpoint is primary fascial closure (PFC), the successful closure of hernia defect at the conclusion of the case. Additional secondary outcomes regarding clinical course and patient-reported outcomes will be captured at 30 days, 90 days, 1 year, and 2 years. Exploratory outcomes include cost and healthcare utilization information, as well as comparison of physiological parameters between treatment groups. Data Stewardship: Primary data capture occurs in the ACHQC registry, supplemented by an institutional REDCap database for variables not routinely captured (e.g., physiologic measures) in the registry.