Objective: This study was designed to: detect the characteristic anal manometric pattern in patients with chronic anal 
fissure, compare prospectively the changes in anal function following tailored sphincterotomy according to the height of the fissure versus limited sphincterotomy to the distal fourth of the sphincter length. 
Patients & methods: A pre-operative computer-generated anal vector manometric studies were performed for sixty 
patients suffering from anal fissure and twenty controls. Anal manometry was repeated one week and five weeks following each type of sphincterotomies. 
Results: Forty-one patients had high RAP (68.33%) while 19 patients had normal RAP (31.66%). Contrary to the 
controls, RAP-1 cm in patients with chronic fissure was significantly higher than global RAP (p=0.00358) with a 
significantly higher posterior pressure in the distal 1 cm of the anal canal. No significant difference between mean RAP-1 cm of normotensives and hypertensives. TLS resulted in postoperative hypotonia which was more evident in females and 
normotensive patients (mean RAP = 57.00±7.75cm H2O, 48.60±9.08 cm H2O respectively). On the other hand, no evident hypotonia could be demonstrated following LLS. Normotensive patients have significantly shorter FACL than hypertensive patients (3±0.5, 3.51±0.43, p=0.00013). Neither TLS nor LLS resulted in a significant change in the FACL. The width of high pressure segment as a percent of FACL was significantly less in normotensive patients (20.57±7.23 %) than in hypertensive patients (29.44±11.11%) (P=0.002378). Normotensive fissure patients have a significantly more distally located HMRP than hypertensive patients (0.82±0.21, 1.24±0.46, p=0.000326). Two patients (6.66%)had persistent fissure after TLS, while three patients (10%) required further treatment following LLs, two for persistent fissure and one for recurrent fissure six months post-operatively. 
Conclusions: Elevation in the mean resting anal pressure is attributed to distal hypertonia secondary to presence of the 
fissure. Anal physiology was significantly more preserved following LLS than after TLS with absence of post-operative 
hypotonia. The rate of imperfect control using limited technique is compared favorably with the tailored sphincterotomy. 
Moreover, the success rate of LLS was closely approximate to that of TLS.