Transvaginal synthetic mesh: Complications and risk factors

INTRODUCTION — Since the introduction of synthetic mesh into gynecologic surgery, studies have reported adverse events following all types of mesh-based procedures. While the risk for complication varies based on the specific surgical indication [stress urinary incontinence (SUI) versus pelvic organ prolapse (POP)], surgical procedure, and route (vaginal versus abdominal), there are commonalities to mesh-related complications.

This topic will review risk factors for and types of mesh-related complications in reconstructive female pelvic surgery. Additional information regarding the use of synthetic mesh in gynecologic surgery and the management of complications is found in related topics:

●(See "Transvaginal synthetic mesh: Use in pelvic organ prolapse".)

●(See "Transvaginal synthetic mesh: Use in stress urinary incontinence (SUI)".)

●(See "Transvaginal synthetic mesh: Management of exposure and pain following pelvic surgery".)

RISK FACTORS FOR MESH COMPLICATION — The risk of mesh complication varies with the surgical indication for mesh insertion. Complications are more common when synthetic mesh is used for the surgical treatment of pelvic organ prolapse compared with stress urinary incontinence (SUI), although SUI surgery is performed more frequently [1]. A systematic review of 11 trials and 9 studies reported the following additional risk factors for mesh-related complication: operative technique, surgeon experience, previous prolapse repair, concomitant hysterectomy, total mesh repair, mesh properties, young age, sexual activity, and smoking [2]. In addition, younger age appears to be a risk factor for mental health sequelae should a mesh-related complication occur. A population-based study of over 57,000 women with a midurethral mesh sling reported that, for women who experienced mesh complications that required surgical intervention (n = 1586, 2.8 percent of study group), age less than 46 years was associated with increased risk of depression and self-harm [3]. Increased risk of self-harm was also reported for women aged 46 to 66 years who experienced complications. This study highlights the need for clinicians to evaluate women who experience mesh-related complications for problems beyond the scope of the mesh complication itself, such as depression. Discussion of screening tools for discussion is presented separately. (See "Screening for depression in adults".)

EPIDEMIOLOGY — While mesh complications can occur following surgery for both pelvic organ prolapse (POP) and stress urinary incontinence (SUI), mesh-related complications are more common following POP surgery, particularly when the synthetic mesh is placed vaginally. As a result of the disparate complication rates for the two procedure groups, the US Food and Drug Administration banned surgical mesh for transvaginal POP repair in 2019, but kept the class II classification for transvaginal mesh used in the surgical treatment of SUI and for transabdominal mesh for POP [4-6]. (See "Transvaginal synthetic mesh: Use in pelvic organ prolapse", section on 'Issues surrounding synthetic mesh for POP'.)

Studies demonstrating the disparate mesh complication rates by procedure indication include:

●For POP surgery – In a systematic review of 11 trials and 9 studies that assessed mesh-related complications after POP repair, the mean total complication rates were 27 percent for anterior repair, 20 percent for posterior repair, and 40 percent for combined repairs [2].

●For SUI surgery – In a meta-analysis of 11 trials and 5 studies, the combined mesh erosion rates for retropubic and transobturator sling procedures ranged from 0 to 15 percent [7]. A later study of 1881 women who underwent a sling procedure for primary SUI reported reintervention rates for mesh exposure of 2 to 3 percent at eight years of follow-up [8]. Results were similar for the two sling types.

Complications from mesh-based surgery for prolapse or incontinence can occur any time postoperatively and continue to rise over time. Examples of early and remote synthetic mesh complications for prolapse and anti-incontinence procedures are highlighted by the studies below:

●In one study of nearly 28,000 women undergoing prolapse surgery, 3 percent of women who had transvaginal mesh prolapse repair required reintervention within one year, although 2 percent of women who did not receive transvaginal mesh also underwent reintervention [9]. The risk of reintervention was greatest for the women under age 65 years who received transvaginal mesh compared with similarly aged women who did not receive transvaginal mesh (hazard ratio 1.76).

●In a retrospective cohort study including nearly 60,000 women who underwent a mesh-based procedure for SUI, the risk of complication requiring reintervention was 1.2 percent at one year and cumulatively increased to 3.3 percent at 10 years [10]. Thus, 10 years after SUI surgery, 1 of every 30 women required a second procedure for mesh-related complications. In this study, complications were defined as mesh exposure, fistula, pain, or urinary retention.

PREVENTION OF MESH-RELATED COMPLICATIONS — The key points for preventing complications from synthetic mesh, regardless of procedure indication, are:

●Optimize modifiable risk factors

●Use most recent scientific evidence regarding the biomechanical properties of the material to select the transvaginal mesh type

●Use optimal surgical technique

Modifiable risk factors — Medical therapy is adjusted to optimize the medical condition. In addition to smoking cessation, common gynecologic conditions relevant to successful pelvic floor surgery include pelvic floor dysfunction and vaginal atrophy or ulcerations. (See "Overview of preoperative evaluation and preparation for gynecologic surgery", section on 'Medical comorbidities'.)

●Smoking – Cessation therapy is encouraged as a general health measure as well as a risk-reduction technique for mesh-related surgical complications. Active tobacco users have a 5.2- and 3.2-fold increased risk of mesh exposure following sacrocolpopexy and vaginal mesh repair, respectively [11,12]. Smoking has also been associated with increased risk of midurethral sling revision and/or removal [13]. Smoking cessation strategies and treatment are discussed elsewhere. (See "Strategies to reduce postoperative pulmonary complications in adults", section on 'Smoking cessation'.)

●Pelvic floor dysfunction – We use the patient history and physical examination to screen for baseline pelvic floor dysfunction and dyspareunia. Concerning history includes symptoms of urgency, frequency, dyspareunia, pelvic pain, and sexual abuse; suggestive physical examination findings include abnormal pelvic tone or sensation during palpation of the levators, obturator internus, vaginal sulci, and vulva. In one cohort study, 33.5 percent of women (105 of 324) had dyspareunia at the time of questionnaire [14]. Patients with abnormal findings are referred for treatment of the underlying condition. In addition, they are explicitly informed that surgery, if undertaken, is not meant to improve these symptoms and may make them worse.

●Bariatric surgery – A case-control study reported that women who had previous bariatric surgery were at seven times greater odds of mesh exposure following a midurethral sling compared with women without bariatric surgery [15]. Optimization of nutritional deficiencies prior to the sling may be beneficial in minimizing mesh exposure in this population of patients.

●Vaginal atrophy and ulceration – Preoperatively, the authors treat patients with topical estrogen until the symptoms resolve and then continue local estrogen therapy postoperatively. While this approach is common practice, the ability of vaginal estrogen to reduce mesh complications has been questioned by a retrospective cohort study and a small prospective trial [16,17]. (See "Genitourinary syndrome of menopause (vulvovaginal atrophy): Treatment".)

Transvaginal mesh properties — Meshes used for stress urinary incontinence and pelvic organ prolapse are macroporous (pore size >75 microns) polypropylene sheets. Evolving evidence suggests that textile properties, structural properties, and mechanical behavior of polypropylene mesh may influence mesh risks [18]. Meshes with microporous components (pore size <10 microns) or with multifilament weave are avoided because of increased risk of mesh-related complications [19]. These materials undergo an encapsulation response and are more prone to exposure, sinus tract formation, and infection [19-21]. (See "Reconstructive materials used in surgery: Classification and host response".)

High complication rates associated with ObTape and IVS tunneler (both of which are encapsulated) have led to both being removed from the market. In a secondary analysis of the Colpopexy and Urinary Reduction Efforts (CARE) trial, Gore-Tex mesh use was associated with 4.2-fold increased risk of mesh exposure compared with polypropylene mesh [11]. These examples highlight the importance of selection of mesh type in minimizing mesh exposure.

Surgical technique — Surgical techniques to minimize mesh exposure include:

●Adequate surgical training – Pelvic surgeons should receive specialized training for procedures that incorporate synthetic mesh and be able to counsel women about the risks and benefits [22]. The surgical training should include specific education in recognition of mesh-related complications. There is evidence that complications are higher among providers with less experience [23]. In a study of 198 patients treated with surgical correction using mesh, the experienced surgeon had fewer exposures than the less experienced surgeons (2.9 versus 15.6 percent).

●Full thickness dissection – A "full thickness" dissection is done via hydrodissection with development of a deeper surgical plane that leaves the pubocervical connective tissue attached to the epithelium. The rationale is to maintain vascular supply to the epithelium and improve healing, with the goal of diminishing graft exposure. In contrast, in traditional plication the vaginal epithelium is separated from the underlying pubocervical connective tissue, which is subsequently plicated in the midline with a delayed absorbable suture [24].

●Tension-free mesh suspension – The mesh needs to be inserted in a tension-free fashion. Excessive tension in the arms has been associated with tight vaginal bands, pain, and exposure [25]. The etiology is unclear but could include mesh shrinkage or inadvertent overtightening at the time of insertion. Following correct placement of transvaginal mesh, there will still be persistent laxity of the vaginal wall to allow for mesh contraction during the postoperative period.

●Prevention of mesh rolling or bunching – The mesh body needs to be trimmed and secured to the underlying tissue to prevent rolling or bunching, as this phenomenon has been observed in patients who experience mesh exposure and pain [26,27].

COMPLICATIONS BY PROCEDURE — The most common complications are mesh exposure, mesh contraction (shrinkage of the mesh), pain (including dyspareunia and associated with contracture), infection, urinary problems, bleeding, and organ perforation [1,28]. Deaths have been reported in association with bowel perforation and hemorrhage. The International Urogynecological Association and the International Continence Society have published a system of terminology and classification of complications related to reconstructive materials to standardize reporting of complications (table 1) [29]. In 2020, the American Urogynecologic Society and the International Urogynecological Association, with support from the AAGL and the Society of Gynecologic Surgeons, published evidence-based treatment recommendations and algorithms to aid shared decision making with patients experiencing mesh-related complications [30].

Mesh for POP and SUI — While exposure and infection can occur after any synthetic mesh procedure, these complications are much more common following prolapse repair surgery (for pelvic organ prolapse [POP]) compared with incontinence surgery (for stress urinary incontinence [SUI]).

Exposure — Exposure is defined as a condition of displaying, revealing, exhibiting, or making accessible (eg, vaginal mesh visualized through separated vaginal epithelium) [29]. Mesh exposure can be isolated to the vagina or extend to the urethra, bladder, or bowel. Exposure may occur with any reconstructive material (eg, synthetic or biograft) and following any pelvic reconstructive procedure [20,31]. Exposure is a potential complication for all types of procedures using nonabsorbable mesh. Patients with mesh exposure may be asymptomatic [32,33].

The pathophysiology of mesh-related complications is not known, but hypotheses include:

●Incorrect vaginal dissection (eg, too superficial)

●Wrong suture choice [34,35]

●Excessive tension

●Placement of a foreign body via a contaminated vaginal field

●Poor wound healing (eg, due to vaginal atrophy, smoking, history of bariatric surgery, or use of immunosuppressive medications)

Type of procedure — Transvaginal mesh kits are associated with the highest risk; midurethral slings are associated with the lowest risk of exposure.

●POP procedures

•Anterior compartment surgery – Mesh exposure rates range from 3.2 to 17.2 percent [22,36,37]. Up to 7 percent of these women will require surgical correction [38].

•Multiple-compartment surgery – Mesh exposure rate of 18 percent has been reported [36,39].

•Vaginal mesh procedures, multiple types – Vaginal mesh exposure rate 18 percent in an analysis of three trials [36].

●Midurethral slings – Mesh exposure varies from 0 to 4.7 percent [40-44]. Risk factors for mesh exposure after midurethral sling placement include trocar injury; type of material (type 2 and 3 higher than type 1); diabetes, bleeding, or surgical complications; vaginal incision length greater than 2 cm; and history of prior prolapse, prior bariatric, or incontinence surgery [42,45]. (See "Reconstructive materials used in surgery: Classification and host response", section on 'Classification'.)

Concomitant hysterectomy — Concomitant hysterectomy may increase the risk of exposure. In a retrospective cohort study of 201 women, the rates of exposure with hysterectomy plus anterior repair versus anterior repair alone were 23.5 and 0.8 percent, respectively [46].

Route of repair — Transabdominal prolapse repair may have lower incidence of mesh exposure than transvaginal repair. In a randomized trial of 108 women, the abdominal route surgery (laparoscopic sacrocolpopexy) had a mesh exposure rate of 2 percent compared with 13 percent in the vaginal mesh group [47]. However, the transvaginal repairs in this study were done with mesh kits, which have higher mesh exposure rates than non-kit mesh repairs [36].

Mesh exposure may be treated medically for small (less than 0.5 cm) exposures or surgically for large or complicated exposures; multiple procedures may be required [48]. Management of mesh exposure is reviewed in detail separately. (See "Transvaginal synthetic mesh: Management of exposure and pain following pelvic surgery".)

Infection — Wound and urinary tract infections (UTIs) are not exclusive to synthetic mesh surgery. However, these are the most common types of infection following transvaginal mesh placement; the risk differs between prolapse and incontinence surgery.

●For POP repair, a 2008 systematic review primarily comprised of mesh studies reported UTI rates of 0 to 19 percent and vaginal wound infection rates of 1 to 3 percent, but no comparative data were included for the rate of infection in suture-only repairs [49].

●For midurethral sling procedures, UTIs are reported in up to 32 percent of patients [50]. The use of prophylactic antibiotics reduced the rate of immediate postoperative UTI to 7.5 and 17.2 percent in two studies [50,51]. Vaginal wound infections following midurethral sling procedures occur infrequently and have not been reported in the literature. (See "Surgical management of stress urinary incontinence in females: Retropubic midurethral slings", section on 'Urinary tract infection'.)

Abscess formation (pelvic, retropubic, or other sites) can occur following transvaginal placement of reconstructive materials [52-54]. For POP repair, case series of 20 to 90 patients have reported abscess formation in 1.6 to 4.2 percent [55-57]. Isolated case reports have described abscess formation following midurethral sling procedures [58-60]. (See "Surgical management of stress urinary incontinence in females: Transobturator midurethral slings", section on 'Other complications'.)

Mesh for POP — While the complications listed below can occur with synthetic mesh placed for the treatment of both POP and SUI, these events are much more common who have had mesh placed for the repair of POP, particularly transvaginal surgery.

Contraction — Contraction appears to cause painful vaginal bands, resulting in dyspareunia or pelvic pain. In a case series of 17 women who underwent POP repair with mesh kits and developed postoperative vaginal pain and dyspareunia, all were found to have focal tenderness along contracted vaginal bands on pelvic examination [25]. Excision of the palpable band or all of the accessible mesh resulted in substantial reduction in vaginal pain for 88 percent (15 of 17 women) and substantial reduction in dyspareunia for 64 percent (9 of 14 women). (See "Transvaginal synthetic mesh: Management of exposure and pain following pelvic surgery".)

Contraction of reconstructive materials following POP repair may be the result of tight vaginal bands and scarring along the course of the mesh arms and is associated with vaginal pain and dyspareunia [25,61-65]. In two sonographic studies, no graft contraction [66] or mesh folding was seen [67]. In a study in rabbits, however, the surface area of synthetic mesh inserted into the abdominal wall was 17 percent smaller by postoperative day 2 [68].

Pelvic pain or dyspareunia — Pelvic pain following transvaginal mesh placement can occur even in the absence of mesh contraction. While residual pain has been reported in up to 30 percent of patients undergoing transvaginal mesh surgery, residual pain can occur after any pelvic surgery, regardless of mesh use [69-73]. Prolapse itself does not typically cause dyspareunia, but some women develop pelvic pain or dyspareunia following surgical treatment, especially following posterior compartment repair [74-76]. The etiology of these symptoms is often not clear, but scarring, graft exposure, or graft contraction may be contributing factors. In a survey study of 160 women who underwent multiple types of pelvic mesh procedures, factors associated with self-reported pain one year postoperatively included younger age (mean 57 versus 63 years), fibromyalgia, worse physical health, higher somatization, and lower surgery satisfaction [73]. (See "Pelvic organ prolapse in females: Epidemiology, risk factors, clinical manifestations, and management", section on 'Effects on sexual function'.)

Midurethral sling surgery is less likely than POP surgery to be associated with dyspareunia [28]. Some data suggest that dyspareunia is more common when a transobturator rather than a retropubic approach is used, but few studies have specifically evaluated this outcome [77].

Management of women who develop pelvic pain or dyspareunia after insertion of transvaginal mesh is discussed elsewhere. (See "Transvaginal synthetic mesh: Management of exposure and pain following pelvic surgery", section on 'Pelvic pain following mesh insertion'.)

Defecatory dysfunction — Posterior wall repair with nonabsorbable mesh has been associated with defecatory dysfunction in 1 and 10 percent of women in two small observational studies [78,79].

Other — Also reported in the systematic review described above [49]:

●Granuloma formation – 3 to 39 percent

●Visceral injury (eg, bladder, rectal, and vaginal perforation) – 1 to 4 percent

●Bleeding complications – 0 to 3 percent

●Fistula formation – 1 percent in POP repair

Mesh for SUI

Voiding dysfunction — Voiding dysfunction is one of the most common complications of midurethral sling procedures, occurring in 20 to 47 percent of patients, depending on diagnostic criteria used. Most voiding dysfunction is transient and self-limited. Data from several large, well-designed randomized trials have shown that the rate of voiding dysfunction requiring urethrolysis is less than 3 percent [43,80-83]. (See "Surgical management of stress urinary incontinence in females: Retropubic midurethral slings", section on 'Voiding dysfunction'.)

POP repair has been associated with voiding dysfunction rates of 0 to 28 percent. The large range reflects the variation that occurs with the graft type (synthetic or biograft), the location of graft surgery (anterior repair versus posterior repair), and the definition used for voiding dysfunction [49].

Urethral erosion — Erosion of synthetic mesh into the urethra has been estimated to occur in less than 1 percent of cases [43,84]. Women with urethral perforation may present with pain, dysuria, recurrent urinary tract infections, hematuria, irritative voiding symptoms, and/or bladder calculi [85,86]. Urethral erosion is typically diagnosed with cystourethroscopy. In a study of 19 women with urethral mesh erosion who underwent en bloc mesh removal from the urethra, 92 percent (12 of 13) had postoperative urinary incontinence, 60 percent (6 of 10) had pain resolution, 40 percent (4 of 10) had persistent pain, and 11 percent (1 of 9) developed de novo pain after surgery [86]. Despite these outcomes, 54 percent (7 of 13) of women who completed the Patient Global Impression of Improvement rated their postoperative status as "very much better" or "much better." Fifty-three percent (10 of 19) had surgery that utilized grafts or flaps, which highlights the complexity of these procedures. Alternatively, a holmium laser may be used to excise the exposed mesh. Although the procedure is more effective for bladder than urethral exposure, it presents a minimally invasive option for en bloc removal [87].

A case of sub-urethral mesh eroding into the cecum has also been reported [88].

SUMMARY AND RECOMMENDATIONS

●Risk factors for mesh-related complication included operative technique, surgeon experience, previous prolapse repair, concomitant hysterectomy, total mesh repair, mesh properties, young patient age, sexual activity status, and smoking. (See 'Risk factors for mesh complication' above.)

●Serious complications (eg, exposure, contraction, pain, infection) associated with surgical mesh for transvaginal repair of pelvic organ prolapse (POP) are not rare, and complication risks persist for years following surgery. Complication rates are higher for transvaginal mesh POP repairs than for transvaginal mesh incontinence surgery. (See 'Epidemiology' above.)

●The key points for preventing complications from transvaginal mesh are optimization of modifiable risk factors, selection of the mesh type based upon biomechanical properties of the material, and surgical technique. (See 'Prevention of mesh-related complications' above.)

●The most common complications are mesh exposure, mesh contraction (shrinkage of the mesh), pain (including dyspareunia and associated with contracture), infection, urinary problems, bleeding, and organ perforation. (See 'Complications by procedure' above.)

●The most common complication of transvaginal mesh placement is mesh exposure, which can be managed medically (if less than 0.5 cm in size), can require epithelial mobilization to recover, or can require mesh excision. (See 'Exposure' above.)

●Pelvic pain following transvaginal mesh placement can occur in the absence of mesh erosion or contraction. Midurethral sling surgery is less likely than POP surgery to be associated with pelvic pain or dyspareunia. (See 'Pelvic pain or dyspareunia' above.)