Monday, March 26, 2012

Bladder injury/perforation during TVT sling placement: Does route affect rate?

There are a myriad different sling types currently in the market place that can be placed a variety of different ways. All try to achieve the same desired result, that is, cure of stress urinary incontinence (SUI). The paradigm shift in treating SUI occurred in the mid to late 1990s with the introduction of the tension free vaginal tape (TVT). It made sling surgery and cure of SUI a shorter, highly reproducible and out-patient procedure. Sling surgery has been around for more than 100 years and was primarily considered the last resort surgery after other types of failed incontinence procedures, mainly using one’s own tissue, but the introduction of modern mesh slings has lead to wide spread adoption of the surgery and its high success rates are evident in hundreds of peer reviewed literature papers.

First, a brief word on mesh. Recently, the FDA has issued bulletins on mesh for vaginal surgery related to pelvic organ prolapse, most recently in July 2011. It did not call attention to mesh for sling surgery. Although mesh is mesh, the amount, technique, and final position of mesh for incontinence surgery is far different than for pelvic organ prolapse. Mesh for slings for incontinence surgery is considered the standard of care, in the US and worldwide, although there are still other types of incontinence surgeries available, including non-mesh slings, injections and abdominal surgeries (Burch, MMK), which are either less successful, more complex, or reserved for specific indications. All mesh are foreign and must heal and scar into the body. A well trained urologist or gynecologist will have the skills to perform a sling relatively quickly, with little complication, will have familiarity with several ways to place slings, and be willing to dealing with potential complications, though they are low.

Many different methods of placement of slings exist, and method of placement depends in large part on surgeon training, patient body habitus or prior surgeries. The classic TVT as first described is not as often performed any longer as much as it used to be in the US due to modifications and different ways to place slings, but there is always debate as to which is the best method, as it relates to reproducibility, success and complication rate.

Case in point. A recent paper was published looking at two groups of patients receiving a TVT for SUI, where the method of placement differed between groups. The first group consisted of vaginal passage of the needles (bottom- up) position, and the other group consisted of abdominal passage of the needles (top- down) position. Injury to the bladder is one of the known risk factors during sling surgery. The rate of injury we know goes down as experience goes up, and as knowledge of anatomy increases, and as proper patient selection is used. During adopting of new techniques, is there a method of placing slings that will reduce bladder injury risk in less experienced hands? That was the goal of the study.

The greater injury risk was with sling placement in a bottom up approach vs. a top down approach , 37.9% vs. 6.8%. The first 5 cases is where the most injuries occurred and then they became less likely over time. There were no other differences between the two groups when compared.

Part of the analysis of the study by the authors from St Louis was an attempt to train less experienced surgeons in a technique that will lead to less injury.  If after training, there are surgeons who do not perform this surgery frequently, then one can conclude that the top down approach for low volume operators is the safer approach. The anatomic landmarks are better identified with the top down approach.  If the low volume operator is not familiar with several sling techniques or if the patient is complex or had prior surgeries, then the patient may want to be referred to a more skilled surgeon.  The patient is also responsible for asking the right questions when discussing potential surgery and ask the doctor how many slings they have done, and what his/her complication and/or success rates are. The patient is not a passive bystander in her medical care, and should ask these important questions.

The importance of this study findings is obvious. Less bladder injury is always desired, as it leads to less bleeding, less bladder catheter time, and more patient satisfaction. It is also important to always check the bladder at the time of surgery with a scope regardless of type of sling performed. This takes just a minute but missing an injury can have serious consequences.