Diagnosis of Anal Sphincter Injuries by Manometric Radial Asymmetry

ABSTRACT

PURPOSE: This study was undertaken to evaluate how well anorectal manometry diagnose anal sphincter injury, especially with regard to the parameter of radial asymmetry. METHODS: Anorectal manometry were performed in 27 male patients with anal fistula of transsphincteric type. The postoperative values of each manometric parameter including radial asymmetry (RA) were compared with preoperative ones. And also, the association between the sites of functional defect assessed by cross-sectional pressure data under station pull-through (SPT) technique and those of anatomical defect made by fistulotomy operation were determined. RESULTS: Under rapid pull-through (RPT) technique, maximum resting pressure (MRP); 113.1 21.3 mmHg (preoperative value) vs 68.0 18.5 mmHg (p=.000) (postoperative value), RA of MRP; 16.7 3.7% vs 24.1 7.5% (p=.002), Maximum squeeze pressures (MSP); 199.0 35.2 mmHg, 169.6 48.7 mmHg (p=.006), RA of MSP; 15.5 3.7%, 22.8 3.5% (p=.000). Under SPT technique, MRP; 100.4 39.5 mmHg vs 71.2 34.6 mmHg (p=.000), RA of MRP; 16.3 7.9% vs 24.2 10.8% (p=.026), MSP; 299.1 71.6 mmHg vs 231.4 90.3 mmHg (p=.004), RA of MSP; 13.0 6.1% vs 22.0 8.4% (p=.001). Sites of functional defects interpreted upon SPT data were coincidental with sites of anatomical defects made by fistulotomy in 88.9% (MRP) and 92.6% (MSP) of cases. CONCLUSIONS: Manometric radial asymmetry could be a useful parameter in diagnosing anal sphincter injury and locating the site of defect.