RESULTS
A total of 82 women had surgical repair of major OASIS. Of these, 73 women (89%) returned the questionnaire at a mean 26 months post sphincter repair and these women formed Group A. Groups B and C consisted of 55 and 83 patients respectively recruited during the same period. Patient characteristics are presented in Table 1. Of note, patients in Group C were significantly younger than those in Groups A and B. The overall prevalence of IBS in our cohort was 12.8%
The inability to defer defecation for more than 15 minutes occurred more commonly in Group A patients (46.6%) versus Group B (21.8%) and Group C (27.7%) and this was statistically significant (p=0.009).
In Group A, 46 patients (63%) had no residual sphincter defect, 10 patients (13.7%) had an isolated internal anal sphincter (IAS) defect, 5 patients (6.9%) had an isolated external anal sphincter defect (EAS), and 12 patients (16.4%) had a defect in both IAS and EAS. There was no significant difference in Wexner score in relation to localisation or combination of sphincter defects and there was no difference in Wexner score between those patients that had any sphincter defect versus those that did not (Table 2). Group A patients had significantly higher mean Wexner scores than Group B and C patients. Perfect continence (Wexner score 0) was significantly less present in Group A (21.9%) patients compared with Group B (50.9%) and Group C (45.8%) (Table 3). There was no difference between Groups in number of patients with Wexner scores of 9 and above.
When the presence of IBS was taken into account, Wexner scores were significantly higher in patients with IBS and this was observed separately in all three patient groups. Inter-group comparison showed that when IBS was present, Group A patients had significantly higher Wexner scores than Group B and C patients. Interestingly when IBS was absent there was no significant difference between Wexner scores in inter-group comparison of all three groups (Table 4).
Wexner scores were also found to be significantly higher on intra-group comparison in all three groups based on those that could not defer defaecation longer than 15 minutes (Table 5). Inter-group comparison showed that Group A patients maintained significantly higher Wexner irrespective of whether they were able to defer defaecation for 15 minutes. Furthermore, the inability to defer defaecation for more than 15 minutes was not significantly related to an isolated IAS defect (7/34 vs 5/39, p=0.37), isolated EAS defect (1/34 vs 4/39, p=0.22), both IAS and EAS defect (8/34 vs 2/39, p=0.79) or any sphincter defect (14/34 vs 13/39, p=0.49).
For the total group, IBS presence in combination with inability to defer defaecation for 15 minutes was associated with the highest Wexner score (Table 6). Backwards stepwise linear regression including the following variables: age, IAS and or EAS ultrasonographic sphincter defect (isolated or in combination), parity, presence of IBS, inability to defer defaecation more than 15 minutes and BMI was performed. In the final model (adjusted R-square .241, F=.7.68, p=0.002) presence of IBS (Beta=3.48, p=0.002) and inability to defer defaecation for more than 15 minutes (Beta=2.17, p=0.044) were the significant independent factors predicting increasing Wexner scores in Group A patients.