LAUSR

BACKGROUND Lateral pelvic lymph node dissection for rectal cancer is challenging due to the complexity of the pelvic wall anatomy, and incomplete lateral pelvic lymph node dissection may result in local recurrence in the lateral pelvis. Although three-dimensional printed organ models are useful for understanding spatial anatomy, it currently remains unclear whether they improve surgical outcomes. OBJECTIVE We aimed to assess whether the surgical effectiveness of lateral pelvic lymph node dissection is increased by the use of individualized three-dimensional printed pelvic models. DESIGN This was a retrospective study using a propensity matching analysis. SETTINGS This study was conducted at a university hospital in Japan. PATIENTS In total, 115 patients comprising 184 pelvic sides (right, 85 sides; left, 99 sides) who underwent lateral pelvic lymph node dissection for colorectal adenocarcinoma between January 2012 and December 2019 were enrolled. INTERVENTIONS We compared surgical outcomes using three-dimensional printed pelvic models with control outcomes. MAIN OUTCOME MEASURES The primary outcome was the number of harvested lateral pelvic lymph nodes on one pelvic side after the propensity matching analysis. RESULTS After matching, 35 pelvic sides each were allocated to the three-dimensional model and control groups, and no significant differences were observed in patient characteristics between the two groups. The number of harvested lateral pelvic lymph nodes was significantly higher in the three-dimensional model group (median, 9; range 3-16) than in the control group (median, 6; range, 0-22) (p=0.047). LIMITATIONS This was a retrospective study using propensity score matching. However, historical backgrounds were not matched and the majority of lateral pelvic lymph node dissection procedures in the three-dimensional model group were recently performed. This limitation may have influenced surgical outcomes. CONCLUSION The present study demonstrated that by referring to individualized three-dimensional printed pelvic models, colorectal surgeons harvested a larger number of lateral pelvic lymph nodes during lateral pelvic lymph node dissection. This result suggests that three-dimensional printed models help surgeons to complete more detailed procedures. See Video Abstract at http://links.lww.com/DCR/B776.