PATHOPHYSIOLOGICAL ASPECTS AND CLINICAL OUTCOME OF INTRA-ANAL APPLICATION OF ISOSORBIDE DINITRATE IN PATIENTS WITH CHRONIC ANAL-FISSURE

Background-Relaxation of the internal anal sphincter can be achieved b y local application of exogenous nitric oxide donors. Aim-To evaluate the influence of topical application of isosorbide dinitrate (ISDN) on anal pressure, anodermal blood flow, and fissure healing. Patients-Th irty four consecutive patients (male/female: 18/16; mean age (SEM): 39 (10)) with a chronic anal fissure were studied. Methods-All patients were treated for at least six weeks or a maximum period of 12 weeks. B efore treatment and at three and six weeks 22 patients underwent conve ntional anal manometry and laser Doppler flowmetry of the anoderm. Res ults-Within 10 days the fissure related pain was resolved in all patie nts. At six, nine, and 12 weeks the anal fissure was completely healed in 14, 22, and 30 patients respectively. At three and six weeks manom etry was performed at least one hour after the last application of ISD N. These recordings showed a reduction of the maximum resting anal pre ssure (mean (SD), pretreatment 111 (26) mm Hg; three weeks 86 (19); si x weeks 96 (27), p<0.001). Simultaneous recordings of anodermal blood flow showed a significant increase of flow (pretreatment 0.53 (0.17); three weeks 0.80 (0.16); six weeks 0.76 (0.31), p<0.005). The mean (SE M) duration of follow up after successful outcome was 11 (5) months. W ithin this period fissure relapsed in two of 30 patients (7%), eight a nd 10 weeks after treatment had been stopped. Conclusions-Local applic ation of ISDN reduces anal pressure and improves anodermal blood flow. This dual effect results in a fissure healing rate of 88% at 12 weeks . This new and simple treatment modality seems to be an attractive alt ernative for the current available surgical procedures.