Introduction

Synthetic mesh material has been used for surgical treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP) repair since 1990 [1]. The first specifically designed surgical mesh product for SUI and POP was approved by the FDA in 1996 and 2002, respectively [1]. Since then, the development of non-absorbable biocompatible materials, minimal invasiveness, and availability of easy-kits resulted in an exponential increase in the number of mesh surgical procedures performed by both urologists and gynecologists [2••].

According to FDA, in 2010, approximately 300,000 women underwent surgical procedures in the USA to repair POP and approximately 260,000 underwent surgical procedures to repair SUI. From 560,000 surgeries, synthetic mesh was used in one out of three, and three out of four were performed transvaginally [1].

The rationale of using synthetic mesh for POP repair is to improve upon the high-recurrence rates when native tissue is used for reconstruction [3, 4]. The treatment failure can be attributable to technical issues or poor quality of the native tissue. Boreham et al. demonstrated that scar produced by native tissue prolapse repair could restore only 50 % of the pre-operative tissue strength [5]. Moreover, collagenase activity and urinary level of collagen metabolites secondary to the breakdown of collagens I and III are higher in women with SUI and POP [6].

The incorporation of mesh into POP repair has improved the long-term surgical anatomical outcomes and lower recurrence rates. However, vaginal mesh placement is associated with unique potential risks such as vaginal mesh erosion, exposure, and infection. Dyspareunia and chronic pelvic pain, while not unique to the mesh, are also reported [7••, 8]. All of these post-operative complications are not directly related to meshes as other host factors such as patient’s anatomy and surgical technique should be taken into account [2••].

The main objectives of this paper were to review the literature regarding vaginal mesh exposure and, based on the literature evidences, develop an algorithm to help urologists and gynecologists to promptly recognize the problem and treat it effectively with minimal additional morbidity.

Considerations About Synthetic Materials

The pelvic organ support and fecal and urinary continences rely on the integrity of the pelvic muscles and connective tissues. The tissue flexibility and tensile strength decrease with aging and are two of the etiologic factors for POP/SUI among other phenotypic and genetic causes. Therefore, an inert and biocompatible biomaterial would help to provide an additional support for the damaged native tissue [8].

The use of mesh in surgery has been described since 1940 when general surgeons used tantalum mesh for ventral hernia repair [9]. Since that time, a variety of biomaterials have been used for surgical purposes. However, it is only in 1996 when Julian et al. first described the use of Marlex mesh for the treatment of anterior vaginal prolapse [10]. In 2000, Hardiman et al. described the use of polypropylene mesh for cystocele repair [11].

In 1994, Amid et al. described a standard classification of meshes based on pore size and fiber type. Type I, or macroporous mesh, is composed of monofilament polypropylene with pore size greater than 75 um; type II, or microporous mesh, is composed of monofilament polypropylene with pore size smaller than 10 um; type III, macroporous or microporous mesh, is composed of polyester multifilaments; type IV is coated with silicone with pore size smaller than 1 um [12].

Type I monofilament polypropylene mesh is recommended for pelvic organ reconstructive procedures [13]. Large pore size (>75 um) promotes mesh flexibility, facilitates host tissue integration, and allows immune cells to scavenge bacteria [14]. The monofilament polypropylene mesh decreases bacterial adherence, reduces the risk of infection, and is associated with less shrinkage and foreign body response [15]. The types of meshes according to their composition and pore sizes are represented in Table 1.

Table 1 Characteristics of different meshes used in surgical procedures
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Mesh-Related Complications—IUGA/ICS Standardization

The use of different synthetic biomaterials from a variety of manufacturers gave rise to a wide range of mesh-related complications [15]. In order to improve diagnosis and standardize the terminology, in 2011, the International Urogynecological Association (IUGA) and International Continence Society (ICS) developed a classification of the complications related to the insertion of meshes, implants, tapes, and grafts in female pelvic floor reconstruction procedures [16]. The IUGA/ICS classification is represented in Table 2.

Table 2 IUGA/ICS terminology of mesh-related complications
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The IUGA/ICS recommends against using the generic term “erosion” because it does not necessarily suit the clinical scenarios [16]. The word “erosion” should be replaced by terms with greater physical specificity. However, “erosion” remains the most common word used in the literature to describe exposure in the vagina and viscera. The main purpose of IUGA/ICS classification is to facilitate urologists and gynecologists to use the same language and provide more accurate information with regard to diagnosis and treatment. Examples of vaginal mesh exposure and vaginal mesh perforation into the bladder are represented in Fig. 1.

Fig. 1
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a Vaginal mesh exposure. b Intravesical calcified mesh

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Risk Factors for Vaginal Mesh Exposure

Vaginal mesh exposure is the most common mesh product-related complication following SUI and POP repair, occurring on an average of 3 to 10 % of all cases (3 % for sling and 10 % for the anterior and apical prolapse) [7••]. From 2005 to 2010, the Manufacturer and User Device Experience (MAUDE) identified 3979 reports of injuries related to prolapse repair with mesh devices. From 2007 to 2010, the number of adverse events increased by more than fivefold compared to the first 2 years. For these reasons, the identification of potential host risk factors is a good strategy to minimize unexpected outcomes [1].

Diabetes mellitus, advanced age, smoking, concomitant hysterectomy, surgeon’s experience, surgical technique, and proper training in pelvic organ reconstructive procedures have all been shown to be risk factors for vaginal mesh exposure [17–19]. It should be emphasized that all urologists and gynecologists who intend to perform pelvic organ reconstruction procedures should be familiar with principles of pelvic anatomy and pelvic surgeries as well as mesh implantation techniques and post-operative care. Moreover, the FDA recommends that all patients should be informed about the risk factors, benefits, and risks regarding mesh placement before POP and/or SUI repair [1]. The risk factors associated with vaginal mesh exposure are summarized in Fig. 2.

Fig. 2
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Vaginal mesh exposure risk factors

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Clinical Presentation and Diagnosis

The presentation of mesh exposure varies and the management depends upon the extent and location of exposure, associated patient bother, voiding complaints, and involvement of adjacent viscera if any. Vaginal mesh exposure may be detected on a routine exam in an asymptomatic patient or present with complaints of dyspareunia, partner discomfort during intercourse, vaginal bleeding, vaginal discharge, and pelvic pain, whereas bladder or urethral mesh perforation/erosion most commonly can result in overactive bladder symptoms, hematuria, urinary tract infection, urinary retention, urinary calculi, and urogenital fistulae [20–22].

During physical assessment, careful initial digital exam is best supplemented with vaginoscopy using a flexible or rigid scope. It is much more comfortable for the patient than the use of a speculum, particularly in those with pelvic pain. Once vaginal mesh exposure is diagnosed, it would be pragmatic to rule out simultaneous perforation/erosion into the bladder/urethra or bowel and associated collection if any [23–27].

Patients with mesh infection may report foul smelling vaginal discharge and sometimes fever. The incidence of mesh infection ranges from 0 to 8 %, and different pathogens such as Gram-positive, Gram-negative, and anaerobic bacteria have been identified as causative agents [28]. Most mesh infections are biomaterial-related; multifilament polypropilene mesh, non-knitted, non-woven, and composite implants carry higher risk of infection and therefore should be avoided in pelvic reconstructive procedures [29]. Peri-operative antibiotic, thorough antisepsis, gentle tissue handling, and hemostasis are highly recommended strategies to prevent unexpected mesh infections. There is a lack of data in the literature supporting the use of antibiotic-embedded meshes to prevent mesh infection [30, 31].

Management—General Principles

Mesh-related complications should be addressed based on patient’s specific symptoms, mesh location, magnitude, presence of infection, and impact on quality of life. In all cases of mesh exposure, it is highly recommended to rule out simultaneous erosion into the urethra or bladder by cystoscopy [32, 33•, 34–36]. It should be emphasized that the surgeon’s experience in managing complications is very important, as these cases are potentially litigious.

Mesh Exposure Without Infection

Conservative Approach

Conservative approach can be an option for asymptomatic patients with small vaginal exposure or high-risk patients. The basic principle is to stimulate vaginal epithelial growth using local estrogen cream in an attempt to cover the exposure site. The healing process and epithelial regeneration vary between patients and depend on local tissue condition and vascularization. All patients should be advised to avoid sexual intercourse until complete vaginal mucosal regeneration [20]. Based on our experience, it is unlikely that large mesh exposure will have an adequate healing with conservative approach.

Transvaginal Approach

Vaginal approach is the most commonly used method to address mesh exposure; it can be performed as an outpatient or inpatient depending on location, magnitude, and associated comorbidities. Abbott et al. demonstrated that approximately 80 % of patients with mesh exposure need at least one surgical intervention to remove the mesh and 6 % required additional treatment for pain symptoms after mesh removal [37]. Compared to the posterior and apical compartment, mesh exposure requiring surgical excision is more commonly seen after anterior compartment repair, perhaps due to higher percentage of anterior cases being done with mesh [38].

The exposed mesh is removed partially (exposed portion). Rarely, total removal is required in type 1 polypropylene mesh. The decision depends on tissue local conditions such as infection, surgeon’s experience, and patient’s symptoms. If the surgeon chooses to remove partially, it should be done with a rim of healthy tissue. The remaining mesh should be carefully trimmed to not be under the closure. The area should be examined to exclude any sign of infection [2••].

For complete mesh removal, required for non-porous materials or due to a large infected collection in the immediate post-operative period, a midline full-thickness incision is performed on the anterior vagina or original opened incision. The bladder is dissected away from the vaginal wall until exposure of arcus tendineous. The ventral side of the mesh is exposed and surrounding tissues are carefully dissected. The mesh is then removed from under the bladder and the arms from para-vesical fossas. It is often easier to identify the arms and then move directly under the bladder. The vagina is closed with running absorbable suture after rotating a flap if a large defect is present. A step-by-step partial mesh removal is represented in Fig. 3.

Fig. 3
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a, b Vaginal mesh exposure. c Mesh sectioning. d, e Surrounding tissues dissection. f Vaginal closure

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Laparoscopic/Robotic Approach

The laparoscopic and robotic approaches have been described by some groups [39–41]. The dissection is performed through the extraperitoneal access until the Cooper’s ligament and urethra are reached anteriorly and the arcus tendineous posteriorly. Then, the mesh is identified, dissected carefully from the surrounding tissues, and removed. Transvesical laparoscopic and single-port approaches also have been reported in the literature [42, 43]..

Mesh Exposure with Infection

Most cases of mesh infection after prolapse repair are directly related to the type of mesh used in the procedure. Clave et al. reported on 100 polypropylene explants and observed that all implanted polypropylenes had evidences of degradation on scanning electron microscopy analysis. It is important to note that these cases were all from mesh that was exposed and subjected to external infection. They found that meshes with acute infection or chronic inflammation shortened the degradation time [29].

Mesh infection with a collection always requires complete removal of mesh. The surgical procedure can be performed through the vagina, abdomen, or combined approach. In this setting, the two most determinant factors with regard to surgical approach are the surgeon’s experience and concomitant pelvic abscess. In order to avoid unexpected intra-operative events, a pre-operative pelvic CT scan is always advisable when mesh infection is suspected [2••].

Wide-spectrum antibiotic therapy and drainage of any pelvic abscess are mandatory along with mesh removal. Ultimately, microbiological studies from the removed mesh are recommended to guide the best therapy [28]. Figure 4 represents an infected mesh successfully removed through abdominal approach.

Fig. 4
figure 4

a Infected mesh (white arrow) and bladder perforation. b Whole mesh

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Dyspareunia and Mesh Retraction

Dyspareunia may be associated with vaginal mesh exposure, mesh infection, mesh retraction, or severe fibrosis [44]. Approximately 10 % of women who underwent prolapse repair with mesh will develop dyspareunia [45]. If dyspareunia is caused by vaginal mesh exposure or mesh infection, the treatment should follow the same principles mentioned above.

Patients with mesh retraction and/or stiffness of the vaginal wall due to severe fibrosis may present with defecatory and voiding dysfunctions and sometimes with prolapse/SUI recurrence. According to Feiner et al., the most common complaints reported by women with mesh retraction were severe vaginal pain aggravated by movements and focal tenderness over contracted portions of mesh [46]. The treatment option depends on patient’s complaints and quality of life. Conservative approach can be performed initially with analgesics, topic hormonal therapy, or local anti-inflammatory drug injections. Patients with severe pain or poor quality of life most likely need surgical intervention. The main purpose of surgery is to relieve the tension and excise areas of contraction after adequate surrounding tissue mobilization [46]. If a palpable painful cord of mesh is present on a vaginal exam, it is prudent to divide the same and remove a portion of the mesh. However, if the patient presents with muscle pain, the use of trigger point injection can be helpful.

Chronic Pelvic Pain

Chronic pelvic pain is an important concern after POP/SUI repair with mesh. Patients undergoing transobturator sling can develop chronic groin and thigh pain. The incidence reported in the literature ranges from 0 to 10 %. Initially, a conservative management with anti-inflammatory drugs should be attempted, while in few refractory cases, removal of the mesh is recommended [47, 48].

The incidence of chronic pelvic pain after POP repair ranges from 1.9 to 25 %. In these cases, it is highly recommended to perform cystoscopy to assess bladder perforation and mesh calcification. The treatment should be individualized according to the patient’s symptoms and quality of life. In cases of bladder perforation, surgical procedure is mandatory and can be performed endoscopically and transvaginally through the abdominal approach [18, 49].

Conclusions

The exponential increase in the number of mesh-related complications is related mainly to a lack of surgeon’s experience and proper training in reconstructive pelvic surgeries as well as availability of easy-to-handle kits. Despite improvements in short- and long-term outcomes since the introduction of mesh in pelvic surgeries, the incidence of post-operative complications remains elevated. With this in mind, the identification of risk factors and the development of an algorithm (Fig. 5) to facilitate prompt recognition and treatment of vaginal mesh exposure will help urologists and gynecologists to achieve better outcomes and success rates.

Fig. 5
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Algorithm for vaginal mesh exposure

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