Background: Closure of the fascial defect during minimally invasive direct inguinal hernia repair may reduce postoperative bulging and seroma formation but may also increase operative time and tissue tension. The impact of primary fascial defect closure on clinical outcomes remains uncertain.

Methods: We performed a retrospective analysis of 4,209 elective unilateral minimally invasive direct inguinal hernia repairs from the Abdominal Core Health Quality Collaborative (ACHQC) registry. Inverse Probability of Treatment Weighting (IPTW) was used to adjust for 12 baseline covariates.

Results: The cohort included 4,209 patients, with 298 undergoing defect closure and 3,911 without closure. Primary defect closure was associated with a 42% reduction in 30-day surgical site occurrences (SSO) (3.6% vs 6.2%, p=0.034). Rates of early recurrence and reoperation were similar between groups. In the robotic subgroup (2,172 patients), a directional reduction in wound events was observed but did not reach statistical significance.

Conclusion: Primary defect closure during minimally invasive direct inguinal hernia repair was associated with a reduction in short-term surgical site occurrences without increasing early recurrence. These findings support selective closure in patients at higher risk of wound complications.