ORION Study: Mesh Position and Risk During Subsequent Minimally Invasive Abdominal Surgery

Prospective Evaluation of the Impact of Prior Ventral Hernia Repair on Subsequent Reoperations and Neurological Sequelae, Comparing Intra-peritoneal vs. Extra-peritoneal Mesh Placement: the ORION Study

Ventral hernia repair is one of the most commonly performed abdominal surgical procedures worldwide, increasingly carried out using minimally invasive techniques. In this setting, mesh reinforcement is standard practice, but the optimal anatomical plane for mesh placement remains debated. Intraperitoneal and extraperitoneal mesh positions may have different long-term consequences, particularly when patients undergo subsequent abdominal surgery. However, prospective data evaluating the impact of prior mesh position on reoperative risk and postoperative outcomes are limited.

The ORION study is a prospective, multicentre, observational cohort study designed to evaluate the impact of prior minimally invasive ventral hernia repair with intraperitoneal versus extraperitoneal mesh placement on subsequent minimally invasive abdominal surgery. The primary objective is to compare the incidence of intraoperative visceral injury during adhesiolysis between the two mesh positions. Secondary objectives include the assessment of adhesion burden and severity, duration and extent of adhesiolysis, conversion to open surgery, and adhesion-related postoperative complications.

In a predefined subgroup of patients undergoing surgery for ventral hernia recurrence, the study also evaluates short-term postoperative outcomes, including chronic post-surgical pain, neuropathic pain features, sensory disturbances, and analgesic use.

By prospectively collecting standardized intraoperative and postoperative data across multiple centres, the ORION study aims to provide real-world evidence on the long-term surgical and functional implications of mesh positioning in minimally invasive ventral hernia repair.

Inclusion Criteria

• Adults aged 18 years or older.
• Patients who previously underwent minimally invasive ventral hernia repair (primary, incisional, or recurrent) with intraperitoneal or extraperitoneal mesh placement.
• Patients scheduled to undergo elective or emergency minimally invasive abdominal surgery for any indication (including, but not limited to, hernia recurrence, bowel obstruction, cholecystectomy, colorectal, or gynecologic procedures).
• Patients in whom an initial minimally invasive approach is attempted, even if conversion to open surgery occurs after exploratory access or adhesiolysis.
• Ability to provide written informed consent, according to local regulations.

Exclusion Criteria

• Patients undergoing primary open abdominal surgery without an initial minimally invasive approach.
• Patients with a history of open ventral hernia repair as the index hernia procedure.
• Patients without available information on prior mesh position.
• Patients who decline or are unable to provide informed consent.