A comprehensive review of small bowel length measurement: methodological challenges and variability factors

The measurement of small bowel length (SBL) is crucial in clinical contexts such as surgical planning, assessment of nutritional absorption and management of conditions like short bowel syndrome (SBS) and Crohn’s disease (CD). However, the literature reports substantial variations in measurements of average SBL, influenced by a multitude of methodological and patient-specific factors. The present review provides a comprehensive analysis of existing methodologies for SBL measurement, including intraoperative and radiologic approaches, detailing their strengths, limitations, and sources of error. The key factors influencing measurement variability are discussed, including methodological differences related to the measurement tool (e.g. intraoperative vs. imaging-based), bowel preparation process (e.g. stretching of the bowel), starting reference points. Additionally, inter-individual characteristics (e.g. height, BMI, sex) and population-specific factors (e.g. patients with SBS or CD) are assessed for their contribution to SBL variability. The aim pertains to informing clinical practice by providing a critical evaluation of measurement techniques and variability factors that impair standardized measurements of SBL to support research for clinical practice.