Preoperative Botulinum Toxin A Within an Endoscopic Retromuscular Strategy for Ventral Hernia Repair: A Preliminary Prospective Study in J apanese Patients

INTRODUCTION: We have developed a stapler repair technique as an endoscopic retromuscular strategy for ventral hernia repair. Because transversus abdominis release before stapled fascial closure is technically difficult in this technique, preoperative reduction of fascial tension may be valuable even in moderate-sized hernias. Botulinum toxin A may address this limitation, but its necessity and appropriate dosing in Asian patients remain unclear. METHODS: This prospective, single-center study included 10 patients with midline ventral hernias ≥ 5 cm in width. Ultrasound-guided botulinum toxin A was injected into the bilateral lateral abdominal wall muscles using a weight-adjusted dose of 200 units of Botox Vista for patients weighing ≥ 50 kg and 100 units for those weighing < 50 kg. Surgery was scheduled 4 weeks later, and endoscopic retromuscular repair using the stapler repair technique was the preferred approach. CT-based changes in defect width and muscle length, surgical outcomes, and treatment-related adverse events were evaluated. RESULTS: Eight patients underwent endoscopic repair, one open repair, and one intraperitoneal onlay mesh plus repair. Median defect width decreased from 5.7 to 4.5 cm (p = 0.004), and lateral abdominal wall muscles significantly elongated bilaterally. No treatment-related adverse events occurred. Primary fascial closure was achieved in all patients, with no recurrence during a median follow-up of 12 months. CONCLUSION: Weight-adjusted preoperative botulinum toxin A was safe and produced favorable CT-based morphological changes. These changes may reduce fascial tension before stapled closure and help expand the applicability of the stapler repair technique to selected patients with moderate-sized ventral hernias.