PREDICTING THE FUNCTIONAL RESULT OF ANASTOMOSES TO THE ANUS - THE PARADOX OF PREOPERATIVE ANAL RESTING PRESSURE

This article examines the effect of ileal pouch-anal (n = 134) and col oanal (n = 16) anastomoses on resting anal canal pressures in 150 pati ents. METHODS: Patients underwent anal manometry before ileal pouch-an al anastomosis (IPAA) and coloanal anastomosis (CAA) and again six wee ks after ileostomy closure following these procedures. A water-perfuse d catheter system with four radial ports was used for manometry, press ures being recorded during both station and continuous pull through. R ESULTS: Patients with IPAA were younger than those with CAA (34 years vs. 50 years) and had a different ratio of hand-to-stapled anastomosis (1:2.6 vs. 1.3:1). All CAA patients had had rectal cancer while IPAA patients suffered mainly from ulcerative colitis (n = 114) or familial polyposis (n = 10). The mean preoperative resting pressure for all pa tients was 79 mmHg (75-87, 95 percent confidence limit) and the mean f all in this pressure after surgery was 25 mmHg (-21 to -29, 95 percent confidence limit). There was no difference in preoperative pressure o r fall between handsewn and stapled anastomoses, or between IPAA and C AA. CONCLUSION: There was a significant relationship between preoperat ive pressure and change in pressure that held true for all subgroups ( change = -0.7 X preoperative pressure + 31, r = 0.69). Analysis of the functional results confirmed that patients with high preoperative pre ssure are at risk for severe falls after surgery and are not guarantee d a good result. Conversely, patients with low preoperative pressures may actually have an increase with surgery and are not always incontin ent. Patients with low preoperative anal resting pressures should not be denied anastomosis to the anus if they are continent.