RETention of urine After INguinal hernia Elective Repair (RETAINER study I and II).

Purpose: Post-operative urinary retention (POUR) is a well-recognised complication of inguinal hernia repair (IHR). The magnitude of the problem is unclear, and contradictory evidence surrounds postulated risk factors. POUR risks patient distress, catheter-complications and a financial and logistical burden to services. Separately, in the field of IHR, there has been a lack of research into patients' perceptions of surgical 'success'. Our aim is to perform a two-phase, multi-centre prospective study to:Assess the rate, risk factors and impact related to POUR post IH repair.Develop and validate a patient reported outcome measure (PROM) for inguinal hernia repair.

Methods: RETAINER I: We propose a 24-week prospective study with voluntary international participation in 4 week blocks. All patients undergoing elective IH repair (minimally-invasive/open) will be eligible. Standardised data collection will include patient and perioperative factors. Primary outcome will be development of POUR, defined as the need for insertion of a urinary catheter as determined by the treating clinician. Secondary outcomes will be identification of factors predisposing to POUR and the impact of POUR.RETAINER II: A patient reported outcome measure will be developed using representative patient focus groups for item generation, from which an initial questionnaire will be developed and piloted. Validity, reliability, sensitivity and reproducibility will be assessed using the QQ-10 and standard psychometric methodology.

Conclusions: Using an international multicentre collaborative approach will produce the necessary volume of patients, whilst capturing inter-centre variability, to accurately reflect POUR rates and allow analysis of risk factors. This patient pool will provide an excellent opportunity to develop a PROM using appropriate qualitative methodology.

Highlights retainer i & ii protocols: RETAINER (RETention of urine After INguinal hernia Elective Repair) I is a prospective, multicentre, international observational study.RETAINER I aims to explore the incidence of and risk factors for urinary retention following elective inguinal hernia repair.Urinary retention following inguinal hernia repair has a marked impact on patients and creates a significant financial and logistical burden for hospital services.RETAINER II is a prospective, qualitative study, recruiting patients to guide the creation of a patient-reported outcome measure (PROM) for elective inguinal hernia repair.