Background: We sought to compare two synthetic injectable bulking agents, with known efficacy (PTQ™: a silicone biomaterial and Durasphere(®): pyrolytic carbon-coated beads), in the form of a randomised clinical trial.
Methods: Circumferential injection of either agent was performed under local anesthesia and sedation as a day-case procedure. The primary outcome measure was the Wexner incontinence scale. Secondary measures were the short-form 36 (SF-36) quality of life assessment and manometry (maximum resting and squeeze pressures). Follow-up was at 6 weeks, 6 and 12 months.
Results: Thirty-five patients were randomised, 17 to PTQ(®) and 18 to Durasphere(®). Early closure of the trial occurred, due to the removal of the agent PTQ(®), from the Australian Pharmaceutical Benefits scheme. Wexner incontinence scores were significantly better than baseline, in both groups, at 6 weeks and 6 months (P < 0.05), although the improvements were not significant at 12 months. There was no significant improvement for either agent, from baseline, in mean SF-36 scores at any follow-up sessions. There was no significant difference between the two bulking agents, with regard to both Wexner and SF-36 scores, at any of the follow-up sessions. Complications occurred in one patient in the PTQ group (perianal abscess) and did not occur in any of the patients in the Durasphere group.
Conclusions: This trial appears to show that both synthetic agents PTQ(®) and Durasphere(®) are effective and safe, although long-term improvement is limited. In this trial, there appears to be no difference in efficacy between the two agents, over a 12-month follow-up period.