Percentage of the Pelvic Cavity Occupied by a Rectal Tumor and Rectum Affects the Difficulty of Laparoscopic Rectal Surgery

Abstract

[Objective]Recognizing that the safety and efficacy of laparoscopic surgery for rectal cancers have not been fully established, we conducted a retrospective study to determine whether the percentage of the pelvic cavity occupied by a rectal tumor affects the difficulty of laparoscopic rectal surgery or the occurrence of postoperative complications.[Methods] Our study involved 100 patients with rectosigmoid (Rs), upper rectal (Ra), or lower rectal (Rb) cancer treated by laparoscopic surgery at our hospital. Pelvic volume (PV), rectal volume (RV), tumor volume (TV), and respective percentages of the pelvic cavity they occupied were determined on the basis of preoperative computed tomography colonography (CTC) reconstruction images. We analyzed the relation between these percentages and the time to resection, blood loss volume, and number of staples used on the rectal stump (as measures of surgical difficulty) and anastomotic leakage (as a postoperative complication).[Results] Univariate analysis revealed significant differences in age (P = 0.009), PV (P = 0.012), TV (P = 0.042), percentage of the pelvic cavity occupied by the tumor (P = 0.011), and percentage of the pelvic cavity by the tumor and rectum together (P = 0.003) in all patients who developed anastomotic leakage and those who did not. Significant differences were also found in PV (P = 0.029) and in the percentage of the pelvic cavity occupied by the tumor and rectum together (P = 0.041) between the Ra patients in whom anastomotic leakage occurred and those in whom it did not occur. The blood loss volume and number of staples used differed significantly between the high-percentage occupancy group and low-percentage occupancy group (P = 0.050 and P = 0.001, respectively). Further, the number of staples used differed significantly between the high-percentage occupancy Ra group and low-percentage occupancy Ra group (P = 0.019). The data point to increased surgical difficulty and to an increased risk of anastomotic leakage when the percentage of the pelvic cavity occupied by the tumor is high.[Conclusion] The percentages of the pelvic cavity occupied by the tumor and rectum are factors that influence surgical difficulty and the occurrence of complications and should be taken into consideration during the planning stages to ensure safe laparoscopic rectal cancer surgery.

CT-Determined Area of the Pelvis Occupied by an Upper Rectal Tumor as a Predictor of Surgical Difficulty in Patients Undergoing Laparoscopic Rectal Resection

“…Previously, we reported a significantly lower incidence of anastomotic leakage and lower percent volume occupancy among patients who underwent laparoscopic surgery for cancer in the upper portion of the rectum 16) . The volume measurements required complex computer software-based processing, which led us to explore whether pelvic-rectal area occupancy can be determined in an easier manner.…”

“…In our department, we calculate the pelvic volume, rectal volume, and tumor volume, from which we derive the area occupied by rectum and tumor in the pelvic cavity. This occupancy, shown as a percentage, has been found to be a useful predictor of the degree of surgical difficulty and risk of complications when laparoscopic surgery is performed for treatment of upper rectal cancer 16) . In the study described herein, we calculated the area of tumor occupancy simply by measuring the maximum diameter of the rectal tumor and the diameter of the pelvis on selected computed tomography (CT) slices.…”