Chapter 45 CADAVERIC FASCIAL SLING USING BONE ANCHORS

Transvaginal slings are now considered the primary procedure of choice for female stress urinary incontinence (SUI).¹ Although historically female SUI was thought to be caused by either urethral hypermobility or intrinsic sphincter deficiency (ISD), it is now accepted that all patients with SUI have some component of ISD. Therefore, regardless of the cause, a sling procedure may be the first line of treatment recommended. We first began performing the cadaveric transvaginal sling (CaTS) procedure with bone anchors in 1998. Early results showed patient outcome and continence rates to be comparable to those obtained with other techniques and sling materials.²

PREOPERATIVE EVALUATION

A thorough preoperative evaluation is essential before intervention for SUI. Gynecologic history should include number of vaginal deliveries and prior anti-incontinence procedures. Micturition history should include type of incontinence present, type and number of pads used, and a measure of degree of “bother” via questionnaire analysis. The stress-related leakage, emptying ability, anatomy, protection, inhibition (SEAPI) incontinence score is a subjective assessment of patient symptoms and impact on quality of life (Table 45-1).³ Physical examination should focus on assessment and documentation of degree of urethral hypermobility. A thorough examination of the anterior and posterior vaginal wall and the uterus or vaginal cuff should be performed with the patient both supine and standing. Associated pelvic organ prolapse should be repaired simultaneously with the sling procedure. Patients who have undergone prior anti-incontinence procedures may have urethral fixation secondary to scarring at the bladder neck and will require urethrolysis at the time of sling placement. A focused neurologic examination should document any deficits with further evaluation as indicated. Preoperatively, urodynamic evaluation is performed in all patients to confirm SUI and document abdominal leak point pressure. In addition, urodynamic evaluation excludes underlying bladder dysfunction, such as detrusor overactivity or poor compliance, and evaluates the patient’s ability to empty the bladder.

Table 45-1 SEAPI Incontinence Score

Stress-related leakage (“S”)	0 = No urine loss
	1 = Loss with strenuous activity
	2 = Loss with moderate activity
	3 = Loss with minimal activity
Emptying ability (“E”)	0 = No obstructive symptoms
	1 = Minimal symptoms
	2 = Significant symptoms
	3 = Only dribbles or retention
Anatomy (“A”)	0 = No descent with strain
	1 = Descent, not to introitus
	2 = Through introitus with strain
	3 = Through introitus at rest
Protection (“P”)	0 = Never used
	1 = Certain occasions
	2 = Daily, occasional accidents
	3 = Continually, frequent accidents or constant leakage
Inhibition (“I”)	0 = No urge symptoms
	1 = Rare urge urinary incontinence (UUI)
	2 = UUI once/week
	3 = UUI at least once/day

From Raz S, Erickson DR: SEAPI QNM incontinence classification system. Neurourol Urodyn 11:187-199, 1992.

CADAVERIC FASCIA

The use of autologous fascia for transvaginal sling, using either rectus fascia from the anterior abdominal wall or fascia lata from the lateral thigh, has been previously described.^4,⁵ Fascia lata is known to be universally strong regardless of patient age or medical condition. When compared, fascia lata has reproducibly three to four times greater tensile strength than rectus fascia.⁶ Rectus fascia can become attenuated and scarred as a result of cesarean section, abdominal hysterectomy, or other abdominal procedures. However, harvesting fascia inevitably increases operative time, morbidity of the procedure, postoperative pain, and length of hospital stay. For that reason, cadaveric fascia lata (CFL) has become a popular choice for sling material.

Our fascia of choice is a non-frozen CFL, Tutoplast (Mentor Corporation, Santa Barbara, CA). Tutoplast preparation involves a five-step process that includes solvent-dehydration and gamma-irradiation. The process is summarized as follows:

1. Screening: The U.S. Food and Drug Administration serologically screens potential donors and rejects those with a medical or social history that places them at risk of infectious disease or malignancy. The fascia is then inspected and must meet stringent cleanliness, structure, quality, and size standards.

2. Processing: The first step in the cleaning process involves osmotic treatment with various concentrations of saline solution in order to destroy bacteria and viruses and remove most of the antigens from the tissue.

3. Denaturization: The second step of the cleaning process involves treatment with NaOH and H₂O₂ that removes the remainder of antigens and destroys prions (Creutz Feldt-Jakob Disease) and viruses (hepatitis, HIV). Limited exposure to NaOH allows this to be accomplished without significant alteration of the collagenous structure.

4. Preservation: Extraction of water from the tissue is accomplished via organic solvents, resulting in preservation of a dense collagenous structure without a chemical residue.

5. Gamma irradiation: The tissue is cut to various sizes, packaged, and sterilized with gamma irradiation. Radiation is limited to less than 25,000 Gy (2.5 Mrad) to limit weakening of the fascia.

The strength and quality of solvent-dehydrated CFL have been compared to those of freeze-dried CFL, another commercially available preparation. Solvent-dehydrated CFL was found to have significantly greater stiffness, maximum load to failure, and maximum load per unit of graft.⁷

Many authors have published their outcomes using either the solvent-dehydrated or the freeze-dried CFL, and their results have confirmed a difference in the tissue quality. Boone published results on 26 women who underwent pubovaginal sling with solvent-dehydrated CFL (Tutoplast) for SUI.⁸ Minimum follow-up was 12 months. The outcome revealed that 25 (96%) of the 26 patients were “significantly” improved: 77% wore no pads postoperatively, and an additional 15% wore no more than 1 pad per day. No patients required an additional operation for incontinence.

On the other hand, Raz’s group published results on 154 consecutive patients with SUI who underwent pubovaginal sling placement using freeze-dried CFL.⁹ With an average time to follow-up of 10.6 months, 58 (38%) of the 154 patients had recurrent SUI and 26 (17%) required a second operation for SUI. With an average time to reoperation of 9 months, the authors noted that the fascia was either absent, fragmented, or attenuated. Brubaker’s associates reported similar results.¹⁰ Thirty-two patients underwent pubovaginal sling placement with freeze-dried CFL and were available for short-term follow-up. Although 22 (69%) of the 32 patients were objectively dry, the remaining 10 (31%) had recurrent SUI by 6 months’ follow-up. Eight patients underwent reoperation for SUI, and in 7 (87.5%) of them little or no fascia remained at the urethrovesical junction. Fascial strands that were present were sent for histologic analysis and showed evidence of autolysis and degeneration.

As is evident, all commercially available CFL preparations are not the same. The method used to prepare the tissue ultimately affects its tensile strength and surgical results with its use. We prefer to use the nonfrozen cadaveric fascia to avoid the synthetic sling materials that have been associated with higher rates of erosion and/or infection.^11,¹²

BONE ANCHORS

The incorporation of bone fixation in the treatment of SUI was first described with the Marshall-Marchetti-Krantz vesicourethropexy.¹³ Since that time, a number of techniques have been described that involve fixation of suspension sutures directly to the pubic bone, which avoids the risk of nerve entrapment that can occur with attachment to the rectus fascia. Leach described a technique using a needle to place the suspension sutures into the pubic bone,¹⁴ and Benderev later incorporated the use of bone anchors for suture placement.¹⁵

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