BBI Contributing Writer
CHICAGO, Illinois — About 800 of the more than 950 members of the American Urogynecologic Society (AUGS; Washington) attended the society's 22nd annual scientific meeting here in late October, a record attendance despite Sept. 11-related travel worries.AUGS has a primary interest in urogynecology and reconstructive pelvic surgery, with a special interest in recent years for treating female urinary incontinence. More than 15 million Americans suffer from incontinence, and women account for 85% of cases. Of these, 65% suffer from stress urinary incontinence (Table 4). Pubovaginal sling (PVS) procedures are increasingly becoming the procedure of choice among gynecologists and urogynecologists for treating female stress urinary incontinence (SUI). However, there continues to be debate regarding the best way to perform the operation.
|Potential U.S. Incontinence Treatment Patient Pool|
|Patients with incontinence||15 million|
|Female patients||12.8 million|
|Female patients with SUI||8.3 million|
|Patients with ISD||1.3 million|
|Total # of patients in potential pool||7 million|
|Patients getting surgery||200,000|
|Patients available for other therapies||6.8 million|
|Source: The BBI Newsletter|
Although about 200,000 surgical procedures are performed in the U.S. annually, there remain almost 7 million potential patients that have yet to be convinced to undergo a surgical treatment. The objective of both the medical technology industry and physicians is to tap into this large patient pool with less-invasive approaches to treat their discomfort. This was demonstrated by the various innovative approaches to treat SUI as seen in the AUGS exhibit hall, as well as poster and oral presentations.
For those 7 million patients, therapies can range from drugs, pessaries, biofeedback, bulking agents and less-invasive, in-office procedures to minimally invasive surgery. Patients require a customized approach to their treatment, depending on the severity of their condition, their dexterity and their lifestyle choice. Eli Lilly and Co. (Indianapolis, Indiana) is developing a new drug, Euloxetine, that is designed to address 4 million to 6 million patients, but many involved with this sector feel that a large number of patients would rather have a simple treatment rather than take a pill every day of their lives, even if the treatment may have to be repeated a few times in their lifetime.
Injectable bulking agents for ISD
ISD is a subsegment of stress incontinence patients numbering about 1.3 million. ISD is due to an incompetent sphincter, not due to hypermobility of the urethra. Because the cause of the incontinence is different, a different treatment protocol is required to insure the best outcome. A bulking agent provides the greatest chance of success for ISD. The requirements of a successful injectable bulking agent are that it is lasting, biocompatible and nonmigratory. These agents are injected into the tissue surrounding the bladder neck to the midurethra and puff it up, allowing for complete closure of the urethra. Although other products are in development, currently only two bulking agents are on the market: C.R.Bard's (Murray Hill, New Jersey) Contigen and Carbon Medical Technologies'(St. Paul, Minnesota) Durasphere.
As noted, there is great debate as to which of the more than 100 different surgical procedures best corrects incontinence. Many of the procedures — such as anterior repair and endoscopic bladder neck suspension anchored to bone — enjoyed popularity at one point but now are rarely performed. The current gold standard is considered to be a laparoscopic (or conventional) sling procedure. But given that the surgery entails general anesthesia, a hospital stay, and considerable expense, more and more physicians and patients are exploring less-invasive, less-costly alternatives.
Less-invasive sling procedures
One of the first minimally invasive approaches was introduced in 1995 by the Gynecare division of Ethicon Endo-Surgery (Cincinnati, Ohio) with its Tension-free Vaginal Tape (TVT). The procedure differs somewhat from conventional sling procedures in that a minimal vaginal dissection is made, then a tension-free tape is placed around the midurethra without fixation. The operation is performed under local anesthesia in an outpatient setting. Over 40,000 have been placed in patients in the U.S. and more than 200,000 in women worldwide. Critics of this system argue that blind insertion of needles into the pelvic region is associated with a high risk of nicking a major blood vessel and should be avoided. However, clinical studies report only a nominal amount of vascular injuries, with a success rate that rivals conventional sling procedures of a more than 80% cure rate at three years.
While Gynecare currently enjoys its long-term success rate and surprisingly rapid adoption, competitive threats attempt to take market share away. American Medical Systems (Minneapolis, Minnesota) introduced its SPARC system, which is very similar to the TVT system except that the approach is from above the pubic bone, rather than below. This is designed to avoid the risk of vascular accidents, but instead carries a risk of bladder nicks, considered to be the lesser of the two potential injuries.
While the sling surgery procedure is the "gold standard" for surgical correction of female stress incontinence, the high rate of complications associated with the procedure keeps many physicians from providing this option to their incontinent patients. With all sling-type procedures, the biggest concern is overcorrection, or retention. It is estimated that anywhere from 10% to 20% of all incontinence procedures result in complications or bladder obstruction due to overcorrection of the bladder neck during surgery. Overcorrection occurs when the surgeon fixates the sling material in too close proximity to the urethra. This aspect of the procedure is considered "art," as there are no objective standards or scientific methods for achieving optimal sling placement, thereby making it difficult to replicate good clinical results or to teach physicians how to deliver consistent clinical outcomes. This results from not having any way to measure the amount of space between the sling and the urethra. Consequently, both overcorrection and undercorrection (non-cure) occur at an unacceptable rate, which is a major factor contributing to the slow growth of sling procedures. PelviCare (Laguna Hills, California) has developed the Accuset System for measuring the placement of the sling relative to the urethra. This enables surgeons to quantify sling placement and create a common language for surgeons to communicate their results using quantifiable measurements.
This technology is a practical solution to the problem of overcorrection, as it will enable community physicians to replicate and quantify the sling placement of accomplished sling surgeons who have learned to minimize complications. The expected improvement in clinical results and reduced fear of post-operative complications are expected to accelerate the growth of the sling surgery market.
Alternatives to the sling procedure
Stress incontinence is most often caused by weakened pelvic muscles that support the bladder, bladder neck and urethra. A major cause of these muscles weakening is pregnancy and childbirth. With weakened support, the bladder neck and urethra may shift from their normal positions, causing them to drop and allow for urine leakage. The majority of suburethral sling procedures and retropubic urethropexies aim to elevate the endopelvic fascia and restore the urethra to its normal anatomic position. With these procedures, a "sling" is created from the patient's own tissue, or a synthetic or autologous tissue sling is used.
Although many patients do select surgery as their primary cure for their condition, more than 7 million patients shy away from surgery. That is why two new companies will soon be attempting to encourage incontinent patients into physicians' offices offering them a non-surgical approach. These procedures could be positioned as the first line of defense, with surgery only afterward, if needed.
SURx (Livermore, California) has developed a procedure where no sling is used at all, but instead, the patient's own endopelvic fascia is shrunk using radiofrequency energy. A probe is inserted either transvaginally or during laparascopic surgery and heats the collagenous tissue. The resulting shrinkage stiffens and lifts the endopelvic fascia. Theoretically, overcorrection, or retention, is physically impossible because the tissue is not capable of shrinking beyond its original position. The pivotal investigational device exemption trial of the SURx Laparoscopic System included 94 patients at multiple centers in the U.S. At 12 months, the cured/improved rate for this patient group is 85% (using definitions most commonly found in the literature). In total, more than 350 patients have been treated using SURx devices, with the longest follow-up at 3 1/2 years. Recent data show the transvaginal approach can achieve an 87% cure rate (short-term data only at this time.) SURx has its CE mark and is currently selling in Europe through three distributors. The SURx Laparoscopic System is under FDA review and was expected to be commercially available in the U.S. before the end of 2000.
Another company going after the "first line of defense" market is Novasys Medical (Sunnyvale, California), which has developed a catheter-based system that uses radiofrequency energy to increase resistance at the bladder outlet. Besides the patient benefit of a simple 20-minute office procedure, another advantage to this system is a very short learning curve for the doctor. Any physician who can place a Foley catheter should be able to use this product. Since there are no incisions made in the vagina, it is truly a nonsurgical procedure. If proven effective (so far 41 patients have been treated with excellent results), this could be the type of simple procedure that captures those 7 million women waiting for a better way to cure their incontinence.