Bariatric surgery has increased the demand for accurate laparoscopic bowel length measurement. Measures to achieve such precision are scarce in the medical literature. Our study investigates the effect of instruments marking on measurement precision.

Eight consultants and fourteen senior trainees with laparoscopic experience were asked to estimate 150 cm on a piece of string fixed within a standard laparoscopic training stack. Each candidate carried out three pairs of measurement using standard laparoscopic instruments without marking, with 10 cm and with 5 cm mark. Each measurement was timed separately. Candidates were result blinded to prevent any self-correction. Data were analyzed using Bland-Altman plots along with ANOVA tests.

Greater accuracy was achieved via marked instrumentation, the differences being statistically significant (P < 0.01). The improvement was significant regardless of candidates’ level or initial length judgment. Time was almost doubled for the marked measurement. No statistically significance differences were found between the 5 or 10 cm instrument markings for measurement or time.

Marked laparoscopic instrument is a simple and effective way of enhancing length measurement precision regardless of surgeons’ experience.