Collagen injection or artificial sphincter for postprostatectomy incontinence: collagen

Abstract

T nature of this debate would suggest that collagen injection therapy and the artificial urinary sphincter (AUS) are competitive therapies and that only one procedure should be used at the exclusion of the other. In actuality, these therapies are complementary, each one being useful for selected groups of patients. When performing collagen injections, as with any procedure, proper patient selection and the establishment of optimal methods of treatment delivery are crucial for therapeutic success and patient satisfaction. At the time of Food and Drug Administration approval in December 1993, there was little information regarding this, and unfortunately, many patients subsequently “failed” collagen injection therapy because of this lack of data. Thereafter, many physicians were reluctant to treat patients with collagen, and some have since concluded that collagen injection therapy simply does not work for postprostatectomy incontinence (PPI). Recent data would suggest that collagen injection therapy does indeed work well in properly selected patients when the injections are performed according to the methods developed and perfected during the past few years. The data pertaining to proper patient selection are perhaps the most important gathered thus far. A study from 1996 noted that in postprostatectomy patients who used fewer than six pads per day, 72% were dry or significantly improved at 7 months after injection; only 29% of patients using more than six pads per day were dry.1 Additionally, patients who used fewer than three pads per day were dry or significantly improved in more than 80% of cases. Poor prognostic factors included postoperative radiation therapy, adjuvant cryotherapy, and vigorous bladder neck incisions. In the study, the patients rendered dry required a mean of 4.2 injections and 29 mL of collagen. Smith and colleagues2 reported a 38% overall cure rate in 54 patients with a mean follow-up of 29 months; however, in the group of patients who used three pads a day or less, they found a 50% cure rate. Patients rendered dry required a mean of four injections and 20.0 mL of collagen. Bevan-Thomas and colleagues3 recently reported their long-term data of 257 patients after prostatectomy, with a mean follow-up of 28 months. They found that 20% of patients were dry and an additional 39% were significantly improved, for an overall 59% dry or significantly improved rate. Patients who had milder degrees of incontinence and had not received adjuvant radiation or bladder neck incision fared better. A mean of 4.4 injections and 36 mL of collagen were used to obtain dryness in these patients. In a recent study4 focusing on the preoperative evaluation, the abdominal leak point pressure (ALPP) was found to be predictive of postoperative success when using collagen injection therapy. Sanchez-Ortiz and colleagues4 found that patients with a preoperative ALPP greater than 60 cm H2O were cured in 70% of cases, and those with an ALPP less than 60 cm H2O had a 19% cure rate. The data emanating from these studies confirm that the best results can be obtained by selecting patients with milder degrees of incontinence and a preoperative ALPP greater than 60 cm H2O. Important procedural techniques have also been learned from these studies. It is clear that the technique of injecting smaller quantities (2.5 to 7.5 mL) of collagen at longer intervals (greater than 4 weeks) and giving a minimum of four injections yields better cure rates. What this means is that published studies in which an average of two or three injections were given are of little clinical value. Transient but significant improvement after the first or second injection is not a cause for disappointment, as these patients will usually have a good result if additional injections are performed. The opinions contained herein are those of the authors and are not to be construed as reflecting the views of the Air Force or the Department of Defense. From the Department of Urology, Wilford Hall Medical Center, Lackland Air Force Base, Texas Reprint requests: R. Duane Cespedes, M.D., Female Urology and Urodynamics, Department of Urology (MMKU), Wilford Hall Medical Center, Lackland Air Force Base, TX 78236 Submitted: July 2, 1999, accepted (with revisions): August 31, 1999 EDITORIAL