Protocol for the UK cohort study to investigate the prevention of parastomal hernia (the CIPHER study)

Background: Abdominal surgery sometimes necessitates creating a stoma, which can cause future complications including parastomal hernia (PSH), an incisional hernia, adjacent and related to the stoma. PSH affects approximately 40% of patients within two years of stoma formation. Complications of PSH reduce patients’ quality of life and can be severe, e.g. bowel obstruction. PSH
are difficult to manage and can recur after surgical repair. Therefore, it is very important to prevent a PSH. Surgeons create stomas in different ways and both patient and surgical factors are believed to influence the development of PSH. The CIPHER study has been designed to investigate the influence of different surgical techniques on PSH development.

Method: The CIPHER study aims to recruit 4000 patients undergoing elective or expedited surgery with the intention to form an ileostomy or colostomy, irrespective of the primary indication for the planned surgery. For each patient, surgeons describe their methods of trephine formation, mesh reinforcement of the stoma trephine, use of the stoma as specimen extraction site and closure of wounds. The primary outcome is incident PSH during follow-up defined as symptoms of PSH (custom-designed questionnaire) and anatomical PSH, ascertained by independent reading of usual care CT scans. Secondary outcomes include; surgical site infection, Comprehensive Complication Index, quality of life (EQ-5D-5L and SF-12), PSH repair and use of NHS resources.

Discussion: The CIPHER study is the first to investigate detailed surgical methods of stoma formation, in a large, representative cohort of patients with range of primary indications, both cancer and noncancer.