Anal manometry in patients with fissure-in-ano before and after internal sphincterotomy

The motility pattern of the internal anal sphincter was estimated manometrically in 42 patients with fissure-in-ano before and after left lateral internal sphincterotomy (LAS). Resting anal pressure and anal pressure during straining were significantly higher in patients than in controls (132 +/- 21 SD cmH2O vs 81 +/- 14 SD cmH2O P < 0.0002 and 46 +/- 16 SD cmH2O vs 13 +/- 4 SD cmH2O P < 0.0005), but were normal after LAS. Slow waves were more common in fissure patients (86 +/- 6 SD% of total recording time vs 68 +/- 11 SD% of total recording time, P < 0.0002), but also became normal after successful treatment. The presence of ultra slow waves was also more common in fissure patients (P < 0.0001), and although it was significantly reduced postoperatively (P < 0.0001), it did not return to normal. Sampling was less frequent in fissure patients (P < 0.0001) and improved significantly after successful treatment (P < 0.0002). Rectal distension produced significantly less reduction in anal pressure in fissure patients as compared to controls (P < 0.01), but successful treatment returned the response to normal. There were 2 patients with anal fissure who did not heal after left LAS. Those patients and a further 5 patients with non healed fissures after left LAS showed the same pathological manometric features as before surgery. Their fissures were successfully treated by additional right lateral internal sphincterotomy. In conclusion, increased internal sphincter activity is probably an aetiological factor in fissure-in-ano, while successful LAS improves anal sphincter function.(ABSTRACT TRUNCATED AT 250 WORDS)