THE SPARC SLING SYSTEM

Chapter 42 THE SPARC SLING SYSTEM

David R. Staskin, Renuka Tyagi

The SPARC Sling System (American Medical Systems, Minnetonka, MN) is a minimally invasive pubovaginal sling procedure using a loosely knitted, self-fixating, 1-cm wide, 4-0 polypropylene mesh, which is placed at the level of the mid-urethra by passing the suspension needle via a suprapubic-to-vaginal approach.¹^–³ The placement of pubovaginal slings in the treatment of genuine stress urinary incontinence has historically been effective, with excellent long-term outcomes.⁴ This variation of surgical technique results from the drive to decrease surgical morbidity associated with autologous fascia harvesting; it also minimizes the risk of intraoperative complications from minimally invasive sling placement without affecting surgical outcomes (Fig. 42-1).⁵^–¹²

Figure 42-1 (A) Suspension needles: disposable ergonomic, 0.118 inches diameter, 8.2 inches long, and noncutting. (B) Connector-dilators: create the sling tract and enable the suspension needles to be of small diameter, minimizing trauma; do not require sling attachment and tract formation until the needle position has been confirmed; permit untwisting of the mesh after attachment. (C) Mesh sling: biocompatible 4-0 loosely knitted polypropylene. (D) Plastic sheath: permits smooth placement of self-fixating mesh.

MECHANISM OF ACTION

Continence results from multiple factors: resting urethral tone, active sphincter contraction, external compression, pressure transmission, and integrity of anatomic configuration. The success of midurethral sling techniques has prompted a reevaluation of the pathophysiology of genuine stress urinary incontinence and the paradigm for its surgical correction. The mechanism of action for midurethral slings is presumed to be mimicking of the support provided by the pubourethral ligaments and suburethral fascial support.¹³

The importance of urethral stabilization from rotational motion has generally been accepted and was introduced as the “integral theory” based on data collected during radiologic evaluation of micturition.¹⁴ This correlated with structures documented on anatomic dissection and was dubbed an “anatomic hammock.”¹⁵ The importance of urethral configuration suggests that midurethral support prevents separation of the posterior urethral wall from the anterior urethral wall during rotational motion around the inferior portion of the pubic ramus, which appears integral to continence.¹⁶ Suburethral support and stability, in conjunction with urethral coaptation, appears to be the critical factor in the restoration of continence, and elevation of the bladder neck may no longer be a prerequisite.

SURGICAL TECHNIQUE

Positioning

A standard or modified lithotomy position may be elected based on surgical preference and concomitant procedures, with a supine pelvis-inclined (Trendelenburg) position recommended. Adequate distal vaginal exposure for a 1.5-cm midurethral incision is required; however, vaginal retraction sutures or a complex retractor is usually not required for sling placement alone. A weighted speculum and placement of a Foley catheter (14 to 18 Fr) through the urethra to completely drain the bladder is preferred.

Anesthesia

Anesthesia may be selected according to patient and surgeon preference and may include any of the following: general, regional, or local anesthesia with/without intravenous sedation. If a local anesthetic is elected, it should be noted that the primary source of discomfort for the patient is contact with the periosteum of the pubic bone during needle passage. Local injections should include two approaches: the abdominal surface, with local anesthesia of the abdominal skin, rectus fascia, and muscle; and a paravaginal approach, to anesthetize the inferior border of the pubic ramus.

Incisions

Two parallel, 15-blade stab incisions are made above the pubic symphysis 1.5 cm from the midline (3 cm apart). The surgeon should avoid incisions lateral to this area to keep away from the ilioinguinal nerve exiting from the external ring (Fig. 42-2).

Figure 42-2 Suprapubic transverse stab incisions placed 1.5 cm from the midline at the upper margin of the pubic symphysis.

Next, the bladder neck should be identified, the submeatal fold may be elevated using an Allis clamp, and a midline incision is performed through the vaginal mucosa over the mid-urethra. This incision, centered over the mid-urethra, may vary between 1.5 and 3 cm (Fig. 42-3). If the procedure is performed without local anesthetic, a saline injection at the level of the mid-urethra, extending laterally, may be elected to aid in development of the plane of dissection between the vaginal epithelium and the periurethral fascia. Metzenbaum scissors are used to create a submucosal tunnel to the inferior border of the pubic ramus at the level of the mid-urethra bilaterally. The tunnels may be narrow enough for just the needle and connector dilator to traverse the distance, or they may be wide enough to accommodate insertion of a fingertip. With the “narrow tunnel” approach, the fingertip is placed in the paravaginal fornix, outside the incision, in order to palpate needle perforation through the endopelvic fascia (recommended).

Figure 42-3 The vaginal mucosal incision is placed at the level of the mid-urethra, as demonstrated in this image by the “starburst” marks over the urethral meatus and bladder neck. The incision may vary in total length between 1.5 and 3 cm.

Needle Passage

Effective needle passage is divided into two phases: entrance into and traversing of the retropubic space first, followed by perforation of the endopelvic and periurethral fascia. Needle passage may be described in five steps:

1. Approach to the anterior surface of pubic symphysis: Holding the needle itself with the fingertips of both hands, pass the needle from the stab incisions above the pubic symphysis directly down on the bone. During this maneuver, the needle handle is pointed toward the surgeon (Fig. 42-4).

2. Perforation of the rectus fascia and rotation around the superior surface of the pubic symphysis: Slide the tip of the needle along the superior surface of the bone and then direct it downward to perforate the rectus fascia and muscle. Grasping the needle itself near the end with the fingertips rather than the handle permits more control of the straight portion of the curved needle. After fascial perforation, the needle handle should rotate to 90 degrees (up toward the ceiling) as the needle is advanced, to keep the tip of the needle on the posterior surface of the pubic bone (Fig. 42-5).

3. Traversing the retropubic space: Guide the needle inferiorly, with the handle rotated 10 degrees medially—“walking downward along the bone,” again with the fingertips, until the endopelvic fascia is encountered (Fig. 42-6).

4. Palpation of the needletip at the endopelvic fascia: Grasp the handle of the needle; palpate the needletip with the alternate index finger beneath the vaginal wall and guide it to the desired point of perforation. Locate the needlepoint beneath the vaginal wall with the finger and guide it to the perforation point. The perforation point is as lateral as possible against the inferior border of the pubic ramus, at the level of the mid-urethra (Fig. 42-7).

5. Perforation of the endopelvic/periurethral fascia and exposure of the needletip through the vaginal incision:

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Tags: Female Urology Text with DVD

Jun 4, 2016 | Posted by admin in ABDOMINAL MEDICINE | Comments Off

Full access? Get Clinical Tree

Get Clinical Tree app for offline access

Get Clinical Tree app for offline access