Aim: We previously investigated the control mechanism of lumber colonic nerve (LCN) on colonic motility in the animal experiments, and have prospectively introduced LCN preserving low anterior resection (LAR) for rectal cancer on clinical setting. We have demonstrated that LCN preserving LAR has the better bowel function even though autonomic nerve preserving lateral pelvic lymphadenectomy (LPA) was combined. As the LPA is uncommon in the western countries, the aim of this study was to re-evaluate the functional effects of LCN preserving LAR for rectal cancer added the cases without LPA.Patients and
Methods: Since 1994, prospective functional questionnaire have been cumulated consecutively after LAR. Between January 1994 and August 2003, inferior mesenteric artery (IMA) was ligated at the origin of the abdominal aorta (LCN-divided group). Since September 2003, IMA has been ligated at the level of superior rectal artery just beyond the bifurcation of the left colonic artery (LCA), and IMA and LCA were preserved with neural sheath of LCN while dissecting the adipose tissue around the IMA (LCN-preserved group). Total mesorectal excision (TME) with autonomic nerve preservation was performed principally. The LPA was performed for T3 or more advanced cancers in the lower rectum. The end to end anastomosis with double stapling technique was performed in all patients, and the patients whose anastomotic line was within 4cm from the anal verge were enrolled. Functional questionnaire was obtained at postoperative month 1, 3, 6 and 12, and data were analyzed comparing LCN-divided group (n=33) and LCN-preserved group (n=14). Functions were assessed in four aspects: 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 and the level of anastomotic line between two groups. Bowel frequency in LCN-preserved group was significantly less than in LCN-divided group at postoperative month 1 (6.1 +/- 0.8 versus 9.7 +/- 1.0, p < 0.05). Bowel frequency was not significantly different at the other time points, but LCN-preserved group tended to have better functions at any observing time points assessed.
Conclusions: We have revealed the LCN preserving LAR expressed better bowel function at the early postoperative period compared with the conventional procedure irrespective of LPA. LCN preservation may be one of the feasible procedures for improving the postoperative bowel function after LAR.