Evaluation of vector manometry for characterization of functional outcome after restorative proctocolectomy

The impact of 3-dimensional vector manometry (VM) for characterization of the functional outcome of restorative proctocolectomy (RP) was studied in 61 patients at a median of 86 months after RP for ulcerative colitis.

A 14-day continence diary was utilized to quantify continence, urgency, and the frequency of defecation. The clinical outcome data were correlated to the physiology parameters of VM and volumetry.

VM parameters at rest correlated with postoperative continence but not substantially with stool frequency and urgency. High radial asymmetry was significantly correlated with the degree of incontinence (r=0.333, p=0.013). Resting pressures demonstrated a better correlation with the degree of incontinence when documented for the high-pressure zone (HPZ; portion of the sphincter with at least 50% of the maximum pressure; r=0.301, p=0.025) and when performed in the continuous pull-through technique. Stool frequency and urgency were better characterized by volumetry parameters like threshold volumes and pouch compliance. The specificity and sensitivity of the vector volume at rest of the HPZ for the prediction of incontinence was 63.6% and 59.1%, respectively. The corresponding values were 67% and 68%, respectively, for radial asymmetry at rest. Stool frequency and urgency were better characterized by volumetry parameters like threshold volumes and pouch compliance.

A strong anal sphincter at rest and a consistent radial distribution of the sphincter pressure are the most reliable indicators of continence after RP obtained by VM, but their clinical usefulness is limited.