The polypropylene midurethral sling is now well established for the treatment of stress urinary incontinence. Although there has been recent concern over the use of mesh in female pelvic surgery, this treatment has proven to be both safe and efficacious over time. The minimally invasive nature of the intervention, ease of implantation, and efficacy all contribute to the widespread use of this intervention. In addition, it can be performed under local anesthesia if desired, and convalescence from this procedure is much more rapid than traditional fascial slings and retropubic suspensions. Even though the sling itself is a synthetic mesh, there is a low incidence of erosion of the sling material (because of the specific mesh characteristics of the monofilament, widely porous material) if placed correctly and in a tension-free manner. A midurethral sling is best suited for a patient with mild to moderate severity incontinence, although it can be used in more severe cases with the expectation of somewhat decreased efficacy.
Preoperative Preparation and Planning
Patient selection is important for success with this procedure. Patients should be women with symptomatic stress urinary incontinence and reasonable bladder capacity. They should demonstrate stress urinary incontinence on physical examination, and a degree of urethral hypermobility. Patients should also be able to demonstrate that they can empty their bladders appropriately. Preoperative urodynamic evaluation should strongly be considered for patients with underlying irritative urinary symptoms, incomplete bladder emptying, recurrent symptoms after previous incontinence surgery, and pelvic organ prolapse, or at the discretion of the surgeon.
Patient Positioning and Surgical Incision
After induction of the selected type of anesthesia, the patient is placed in the lithotomy position. A full vaginal as well as lower abdominal antibiotic skin preparation should then be performed, and the patient should be draped to expose the vagina and lower third of the abdomen. A weighted vaginal speculum should be used, and the labia minora should be retracted with sutures or a self-retaining ring retractor to maximize visualization of the anterior vaginal wall. Place a catheter at this time.
Starting 1 cm below the urethral meatus, measure a 2–3-cm incision vertically. Alternatively, the midurethra can be best estimated by identifying the point on the vaginal wall midway between the bladder neck and urethral meatus. The bladder neck is easily identified by placing slight traction on the Foley catheter and palpating the balloon ( Fig. 99.1 ). If desired, inject normal saline or dilute lidocaine with epinephrine for hydrodissection. By grasping the vaginal wall just above the incision with an Allis clamp, upward traction can be gained, and this will also aid in visualization. Incise the vaginal mucosa with a no. 15 blade.
Dissection ( Fig. 99.2 ): Grasp one edge of the incision with another Allis clamp. Dissect a flap of vaginal mucosa away from the underlying urethra. This is accomplished using a combination of sharp and blunt dissection. Carry the dissection lateral and superior to the incision, toward the inferior ramus of the pubis. In the proper plane, the glistening white surface of the vaginal wall is seen. If the dissection is too deep, the urethra can be violated or venous bleeding can be encountered. Dissect in this direction until the inferior ramus of the pubis is clearly palpable. Do not pierce the endopelvic fascia. Repeat this dissection on the opposite side.
Suprapubic needle pass ( Fig. 99.3 ): Ensure that the bladder is completely drained of urine. Make paired 1-cm suprapubic incisions directly over the symphysis and 2 cm from midline. Place the index finger of one hand in the vagina and deflect the catheterized urethra away from the side that the needle is being passed from. With the opposite hand, pass the needle through the suprapubic incision. The first resistance to be overcome is the rectus fascia. Staying close to the bone, pierce the fascia. This maneuver may require two hands for better control. Take care to ensure that the tip of the needle is not directed toward the bladder by angling the needle back toward the surgeon. Once through this, ensure that the needle is oriented toward the vaginal incision, and direct it behind the pubis and toward the finger in the vagina, keeping the needle tip in contact with the bone for the entire retropubic excursion. The endopelvic fascia will provide the last resistance. Pass the needle through this and use the finger in the vagina to guide it out through the vaginal incision ( Fig. 99.4 ). Ensure that the needle did not pierce the vaginal mucosa. Repeat on the opposite side, switching hands for the needle passage.