Symptomatic pelvic organ prolapse is common and 13%1 to 19%2,3 of women undergo surgical repair. Reconstructive pelvic surgery is broadly divided into procedures that rely on existing native tissue versus the use of graft augmentation, either with synthetic or biologic materials. Native tissue vaginal repair, while associated with the lowest rate of surgical complications,4 has a high rate of recurrent prolapse. A recent randomized trial of uterosacral versus sacrospinous ligament fixation for POP demonstrated a 30% recurrence rate at 2 years.3
Abdominal sacrocolpopexy (SCP) is considered to be the most durable operation for advanced pelvic organ prolapse with reoperation rates of less than 5%.5-7 Minimally-invasive techniques of SCP, such as robotic-assistance, are associated with improved recovery times and less cost than abdominal SCP without a demonstrable difference in efficacy.8,9 While traditionally reserved for women with vaginal vault prolapse, SCP is increasingly considered as a primary surgical option for women who present with uterovaginal prolapse in an attempt to improve longer-term surgical outcomes. The optimal management of the uterus and cervix in these cases is unclear.
Rationale for total versus supracervical hysterectomy with concomitant SCP
While supracervical hysterectomy and concomitant SCP are associated with lower rates of mesh exposure,10-12 potential negative consequences of a supracervical hysterectomy include morcellation of unanticipated uterine malignancy,13 cervical stump prolapse/elongation, cyclic vaginal bleeding, and reduced anterior vaginal support (Myers EM, Matthews et al., in press). When conducting a supracervical hysterectomy, power morcellators are the most common method used to extract the amputated uterine corpus. The potential risks of power morcellation were recently highlighted by the FDA safety notification which focused on the potential to disseminate fragments of an undiagnosed uterine leiomyosarcoma throughout the abdomen, which negatively impacts prognosis (http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm393576.htm). With these recent developments the focus has shifted towards performing total hysterectomy for delivery of an intact specimen through the vagina.
Vaginal mesh exposure has been a problematic complication with both abdominal SCP and minimally invasive SCP. Widely disparate rates of mesh exposure ranging from 0%14 to 27%15 have been reported. A systematic review of ASCP outcomes in 2004 reported an overall rate of 3.4%,6 and a recent meta-analysis of robotic-assisted SCP reported an overall rate of 2%.16 Some consistent risk factors for mesh exposure are non-Type 1 polypropylene mesh (knitted, small-pore mesh materials) and smoking.17,18 Some studies have identified total hysterectomy as a significant risk factor. In an evaluation of patients enrolled in the CARE trial, 6% had evidence of mesh exposure at 2 years, with concomitant hysterectomy presenting almost a 5-fold increased risk.18 The rate at 6 years rose to 10.5%. 5 More than 50% of subjects in this trial, however, had a non-Type 1 polypropylene mesh. Akyol et al. demonstrated a 2-fold increased risk (12%)19 and Bensinger et al. a 7-fold increased risk (8.2%)20 of concomitant total hysterectomy. In contrast, 4 retrospective studies in which Type1 polypropylene mesh was used revealed no increased risk of mesh erosion with concomitant total hysterectomy.14,21-23 These widely discrepant rates of mesh exposure may be related to surgical technique, graft material and/or suture materials used for mesh attachment.
Rationale for need to study suture material for mesh attachment during SCP
The effect of suture on mesh exposure may be as significant as concomitant hysterectomy or mesh type. At UNC, we reported on mesh exposure using a permanent suture for mesh attachment during SCP with and without concomitant total hysterectomy, with rates of 8% at 1 year.24 There is some evidence that a delayed absorbable suture may reduce the risk of mesh or suture erosion. In a retrospective review comparing braided permanent suture to delayed absorbable monofilament suture for SCP mesh attachment, rates of mesh exposure were reduced in the absorbable suture group (3.7% vs 0%), with no associated POP recurrence.25 Similarly, in another retrospective review, when delayed absorbable monofilament suture was used for SCP mesh attachment in 67 women undergoing total abdominal hysterectomy and SCP, no mesh exposures were noted at a median follow up of 27 months.26 The use of permanent sutures for vaginal mesh attachment has historically been advocated as a means to reduce POP recurrence risk; yet, no prospective study has definitively answered this question. The tradeoff of using a permanent suture may be an increased risk of mesh or suture exposure, as a permanent suture that has breached the vaginal epithelium may serve as a nidus for bacterial seeding, theoretically increasing the risk of mesh exposure. As SCP appears to be a more durable procedure for women with advanced uterovaginal prolapse, there is an urgent need to identify the ideal method of vaginal mesh attachment that minimizes the risk of mesh-related complications while maintaining effectiveness of the POP repair.
Choice of mesh material
Upsylon™ (Boston Scientific, Natick, MA) is a pre-formed Y-mesh that is light-weight (25 g/m2), composed of Type I polypropylene material, with a pore size of 2.8 mm2 and surface area ration of 1.11. It was FDA approved in 2012. The mesh is blue in color that may aide in the ability to detect even small areas of mesh exposure and erosion. No data currently exist regarding the performance of this particular mesh product in SCP. It is lighter in mesh weight than the IntePro™ y-mesh (American Medical Systems, Minneapolis, MN), which we previously used in the comparative trial of robotic to abdominal SCP in which our mesh exposure rates were 8%.
The primary aim of this randomized trial, therefore, is to test the hypothesis that use of the Upsylon™ mesh with a delayed absorbable suture for mesh attachment at the time of robotic-assisted total laparoscopic hysterectomy and SCP will reduce the risk of vaginal mesh and/or suture exposure compared to a permanent monofilament suture. Secondary aims will include an evaluation of the effect of this light-weight mesh and absorbable suture on prolapse and quality of life outcomes and surgical complications at 1 year after surgery.
