Aim: We previously investigated the control mechanism of lumber colonic nerve (LCN) on canine colonic motility, and demonstrated that LCN has both excitatory and inhibitory effects on colonic motility. Changes of bowel habits after low anterior resection (LAR) are another problems on clinical setting. We have prospectively introduced LCN preserving LAR since September 2003, and the aim of this study was to evaluate the functional effects of LCN preserving LAR for rectal cancer.
Methods: Since 1994, prospective functional questionnaire have been cumulated consecutively after LAR. Between January 1994 and August 2003, inferior mesenteric artery (IMA) was ligated and resected with LCN at the origin of the abdominal aorta, and total mesorectal excision (TME) with autonomic nerve preservation (ANP) was performed for lower rectal cancer, principally (LCN-divided group). Since September 2003, IMA has been ligated at the level of superior rectal artery beyond the left colonic artery (LCA) bifurcated from IMA, and IMA and LCA were preserved with neural sheath of LCN while dissecting the adipose tissue around the IMA (LCN-preserved group). TME and ANP were performed in the same manner as in the LCN-divided group. The end to end anastomosis with double stapling technique was performed in each case, and the patients whose anastomotic line were within 4cm from the anal verge were entry in this study. Functional questionnaire was obtained at postoperative month 1, 3, 6 and 12, and data were analyzed comparing LCN-divided group (n=24) and LCN-preserved group (n=10). Function was assessed in four categories: bowel frequency, degree of soiling, ability to distinguish flatus from stool, prolonged defecation and persistent anismus. Subjective questions were expressed as quantitative values utilizing time interval until recognition of symptomatic improvement or satisfaction.
Results: There were no significant differences in the mean age at operation and anastomotic line between two groups. Bowel frequency in LCN-preserved group was significantly less than in LCN-divided group at postoperative month 1 (5.3 +/- 0.9 versus 10.4 +/- 1.2, p < 0.05, respectively). Bowel frequency was not significantly different at the other time points between the two groups, but LCN-preserved group tended to have better functions at any observing time points.
Conclusions: We have introduced LCN preserving LAR for rectal cancer, and have revealed the better bowel function at early postoperative period compared with the conventional procedure. LCN preservation may be one of the feasible procedures for improving the postoperative bowel function after LAR for lower rectal cancer.