Current Status of Synthetic Mesh in Obstetrics and Gynecology
February 1, 2014
Special Feature
Current Status of Synthetic Mesh in Obstetrics and Gynecology
By Chiara Ghetti, MD
Associate Professor of Obstetrics and Gynecology, Division of Female Pelvic Medicine and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO
Dr. Ghetti reports no financial relationships relevant to this field of study.
In recent years, much controversy has surrounded the use of synthetic mesh in gynecologic surgery and more so since the FDA issued a 2008 Public Health Notification (PHN) and 2011 update.1,2 Many of my own patients, as well as colleagues, have inquired and sought guidance regarding mesh and its recommended use. This special feature will summarize FDA position statements pertaining to mesh use in obstetrics and gynecology, review mesh characteristics and data regarding mesh use for prolapse repair and incontinence surgery, and discuss recent American Urogynecologic Society (AUGS) position statements and other resources available from AUGS.
In July 2008, the FDA published a PHN to alert caregivers and patients to the complications associated with transvaginal placement of surgical mesh to treat pelvic organ prolapse (POP) and stress urinary incontinence.1 Although that document stated complications were rare, it enumerated recommendations to reduce the risks of complications. In July 2011, the FDA published an Update on the Safety and Effectiveness of Transvaginal Placement for Pelvic Organ Prolapse,2 which was based on a search of the FDA's Manufacturer and User Device Experience (MAUDE) database as well as a systematic review of the available scientific literature. The FDA statement concluded that 1) in contrast to the 2008 PHN, serious adverse events related to mesh use are NOT rare, and 2) the use of transvaginally placed mesh for prolapse repair does not conclusively improve clinical outcomes.2 Mesh-related complications include but are not limited to acute and chronic infection, tissue contraction due to mesh shrinkage, erosion of the mesh into adjacent structures, and dyspareunia. In September 2011, the FDA convened a panel to hear presentations from patients, women's advocacy groups, individual clinicians, clinical organizations, and industry representatives. The panel concluded: 1) the risk/benefit of vaginal placement of mesh for POP repair is not well-established, 2) controlled studies are needed for premarket evaluation of vaginal mesh for prolapse repair, 3) vaginal mesh should be reclassified to ensure proper study, and 4) manufacturers should conduct postmarket studies.3 Furthermore, this document states the effectiveness of surgical mesh indicated for abdominal sacrocolpopexy (ASC) as well as traditional retropubic and obturator slings is well established; however, the safety and effectiveness of single-incision slings is not well understood. In January 2012, the FDA issued a 522 order requiring manufacturers to conduct postmarket surveillance of transvaginal mesh devices for POP and single-incision mini-slings for SUI.4 Around the time the FDA statements were published, some mesh manufacturers withdrew their products or issued recalls. During this time, numerous lawsuits were filed against physicians and manufacturers, and various organizations have attempted to pass restrictions on the use of transvaginal mesh for prolapse and incontinence.
Mesh Characteristics
In 1959, herniologist Dr. Francis Usher introduced the use of polyethelyene mesh as a prosthetic biomaterial to reinforce soft tissue and augment abdominal hernia repairs.5 By 1963, Usher had changed to using polypropylene mesh. Since then numerous synthetic meshes have been introduced, and the use of synthetic mesh has been widely adopted for many types of surgical augmentation. Synthetic meshes are commonly used in many urogynecologic procedures, including ASC and suburethral slings, and have been utilized in anterior and posterior colporrhaphies. A 2011 survey of AUGS members found overall that 90% of respondents used synthetic mesh for prolapse repair, 93% used synthetic mesh when performing midurethral slings, and 52% when performing vaginal reconstructive surgery for recurrent prolapse.6 Synthetic mesh may provide additional strength and support to native tissue repairs and increase the durability of reconstructive procedures.
In a 1997 publication, Amid classified mesh types and stated that the "prevention of biomaterial-related complications requires in-depth knowledge and the understanding of the physical properties of prostheses."5 This is just as true today for surgeons managing incontinence and prolapse with a wide range of available mesh materials. While we do not yet know what the optimal mesh is for pelvic reconstructive surgery, we have learned that many mesh characteristics impact host responses to the implant. Synthetic meshes vary in material, absorption (permanent and absorbable), composition (mono vs multifilament), architecture (woven vs knitted), and pore size and biomechanical properties (such as density and stiffness). Meshes are classically divided into four categories: Type I, totally macroporous (pore size > 75 microns, includes Marlex and Prolene); Type II, totally microporous (pore size < 10 microns, includes Gore-Tex); Type III, macroporous with microporous or braided components (Mersilene, Teflon, SurgiPro); and Type IV, biomaterials with submicronic pore size (Silastic).5 Meshes made from polypropylene appear to have the lowest mesh erosion rates (0.5%), while higher rates are seen with Mersilene and Polyethylene, and the highest rates with Gore-Tex and Teflon.7 Currently, macroporous polypropylene meshes are preferred due to superior host tolerability. Since macrophages are unable to enter pores < 10 microns, large pore size mesh allows for macrophage migration, resulting in reduced site infection.8 Macroporous structure also allows for increased tissue ingrowth through type III collagen deposition and capillary penetration that ultimately aids in the increased strength of the implant. In addition to porosity, meshes also vary greatly in biomechanical properties. Shepherd et al analyzed seven type I polypropylene meshes available on the market and demonstrated significant differences in biomechanical properties, including stiffness.9 These differences may impact in vivo performance. Heavier (higher density) mesh is associated with greater and more prolonged inflammation and less elasticity, which may contribute to risk of erosion. In summary, lightweight monofilament macroporous polypropylene mesh is currently the preferred mesh for vaginal reconstructive surgery.
Evidence Supporting Use of Synthetic Mesh for Prolapse Repair — Anterior and Posterior Colporrhaphy
Studying treatment success for prolapse repair has been plagued by the arbitrary definition of optimal and satisfactory anatomic outcomes without a full understanding of the relationship between anatomic support and symptom bother.10 Barber et al recommended a definition of success that included absence of bulge symptoms, absence of POP beyond the hymen, and no retreatment for prolapse.11 Without a clear, encompassing, and widely accepted definition of "surgical success," it has been nearly impossible to compare outcomes between surgical studies to determine superior procedures, with or without mesh, short of a randomized controlled trial (RCT).
Anterior Colporrhaphy. A 2004 Cochrane review concluded that Vicryl mesh reduced rate of recurrence of anterior compartment prolapse.12 Subsequently, Altman et al conducted a multicenter RCT with 389 subjects with Stage 2 anterior POP randomly assigned to anterior colporrhaphy alone vs anterior Prolift.13 (Prolift was withdrawn from the market in 2011.) The primary outcome of POP stage 0/1 and absence of vaginal bulge symptoms was assessed at 12 months. This study found improved outcomes with mesh 60.8% vs anterior colporrhaphy alone 34.5% (P = 0.001; RR, 3.6; 95% CI, 2.2-5.9). A 2013 Cochrane review found overall consistent level 1 evidence of increased subjective and objective outcomes for polypropylene mesh vs native tissue anterior colporrhaphy but no differences between groups for prolapse reoperation or dyspareunia.14 The mesh-augmented procedures had increased operating time and blood loss, an increase in de novo apical or posterior prolapse, 10.4% mesh exposure rate, and overall two-fold increase in total reoperation rate. There are currently no RCTs for single-incision kits.
Posterior Colporrhaphy. There is a paucity of literature addressing synthetic mesh augmentation of the posterior compartment, with the majority of studies comparing posterior colporrhaphy alone to repair with biologic graft augmentation. In a review of the literature, Karram and Maher concluded that no studies to date have shown any benefit of mesh overlay or augmentation of a suture repair for posterior vaginal wall prolapse after review of four existing studies comparing posterior colporrhaphy with vicryl mesh, porcine subintestine submucosal graft, or porcine dermis.15 In summary, there is no conclusive evidence to support the use of synthetic or biologic implants to augment the repair for the posterior vaginal wall.
Evidence Supporting Use of Synthetic Mesh for Prolapse Repair — Abdominal Sacrocolpopexy
ASC is a procedure frequently used to correct pelvic organ prolapse and, in particular, apical and anterior prolapse. For this procedure, mesh arms are sutured to anterior and posterior vaginal walls and then secured to the anterior longitudinal ligament of the sacrum. In a comprehensive literature review of studies from 1966 to 2004 with follow-up ranging from 3 months to 6 years, Nygaard et al found the success rate for ASC to range from 76-100%, when defined as lack of apical prolapse.7 The overall reoperation rate for prolapse was 4% (range 0-18%) and the overall mesh erosion was 3.4%. The CARE trial found that at 2 years from ASC, 95% of women had vaginal apical support and 3% had required reoperation for prolapse.16 However, more recently published 7-year outcomes of the same trial found that 2-26% of women had undergone reoperation for prolapse and overall the probability of mesh erosion was 10.5%.17 The 2013 Cochrane review of surgical management of female pelvic organ prolapse, reviewing 57 trials, concluded that sacral colpopexy has superior outcomes to a variety of vaginal procedures, including sacrospinous colpopexy, uterosacral colpopexy, and transvaginal mesh.14 Furthermore, these benefits must be balanced against a longer operating time, longer time to return to activities of daily living, and increased cost of the abdominal approach.
Evidence Supporting Use of Synthetic Mesh for Incontinence — Midurethral Sling
In 1996, Ulmsten introduced the synthetic midurethral sling, tension-free vaginal tape (TVT), for the treatment of stress urinary incontinence. In an early RCT in 2002, Ward and Hilton randomized 344 subjects to open Burch vs TVT.18 After 6 months, there were no significant differences in cure rates. A 2009 meta-analysis of 62 randomized trials found synthetic midurethral slings were as effective as traditional slings and open Burch, and had a 73-82% short-term cure rate at 12 months.19 Objective and subjective cure rates of 78% and 62%, respectively, were reported from the trial of midurethral slings.20 Long-term subjective cure rates have been reported as 77-85%.21,22
ACOG and AUGS Position Statements
In December 2011, ACOG and AUGS published a joint statement regarding the use of transvaginally placed mesh for POP. Their conclusions emphasized the need for continued and rigorous outcome reporting. Placement of vaginal mesh may be performed after extensive informed consent in high-risk individuals in which the benefit of mesh placement may justify the risks. Surgeons placing vaginal mesh should undergo specific training, have expertise in reconstructive surgical procedures, and have a thorough understanding of pelvic anatomy. In addition, ACOG and AUGS strongly supported the development of a registry for surveillance of all mesh implants.23 As further response to the FDA statement, AUGS developed an extensive Transvaginal Mesh Informed Consent Toolkit available on the AUGS website.24 In 2012, AUGS published guidelines for privileging and credentialing of physicians for transvaginal placement of mesh and for sacrocolpopexy to be utilized by appropriate credentialing bodies.25,26 AUGS has launched the Pelvic Floor Disorders Registry, a multicenter national patient registry of patients undergoing treatment of POP to evaluate the effectiveness, safety, and quality of life associated with both surgical therapy and non-surgical management. In March 2013, AUGS published a position statement on the Restriction of Surgical Options for Pelvic Floor Disorders, opposing any restrictions by state or local medical organizations, health care systems, or insurance companies, affirming that the choice should be left to the patient and her physician.27 Then, in January 2014, AUGS and the Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction issued a joint position statement supporting the use of mesh midurethral slings as the worldwide standard of care for the surgical treatment of stress urinary incontinence.28
Conclusion
Recent FDA position statements have increased public attention to the complications associated with the recent development and rapid widespread adoption of surgical mesh kits for prolapse repairs. There has been increased scrutiny and debate about the place of mesh in urogynecologic procedures. While the use of mesh is not supported for some procedures, it continues to have a clear place for ASC and slings. Mesh use is not "one size fits all." The decision to use or not use mesh requires a careful discussion between an experienced and knowledgeable practitioner and his/her patient of the appropriateness of mesh use, including a thorough review of the risks and benefits.
References
- FDA public health notification: Serious complications associated with transvaginal placement of surgical mesh in repair of pelvic organ prolapse and stress urinary incontinence. 2008. Available at: www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm061976.htm. Accessed Jan. 2, 2014.
- UPDATE on serious complications associated with transvaginal placement of surgical mesh for pelvic organ prolapse. 2001. Available at: www.fda.gov/downloads/MedicalDevices/Safety/AlertsandNotices/UCM262760.pdf. Accessed Jan. 2, 2014.
- Obstetrics and Gynecology Devices Panel Surgical Mesh Panel Meeting. Available at: www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/MedicalDevicesAdvisoryCommittee/ObstetricsandGynecologyDevices/UCM271769.pdf. Accessed Jan. 2, 2014.
- FDA Executive Summary. Surgical Mesh for Treatment of Women with Pelvic Organ Prolapse and Stress Urinary Incontinence. Available at: www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials/medicaldevices/medicaldevicesadvisorycommittee/obstetricsandgynecologydevices/ucm270402.pdf. Accessed Jan. 2, 2014.
- Amid P. Hernia 1997;1:15-21.
- Clemons JL, et al; AUGS Research Committee. Female Pelvic Med Reconstr Surg 2013;19:191-198.
- Nygaard IE, et al. Obstet Gynecol 2004;104:805-823.
- Patel H, et al. Int Urogynecol J 2012;23:669-679.
- Shepherd JP, et al. Int Urogynecol J 2012;23:613-620.
- Weber AM, et al. Int Urogynecol J Pelvic Floor Dysfunct 2001;12:178-186.
- Barber MD, et al. Obstet Gynecol 2009;114:600-609.
- Maher C, et al. Surgical management of pelvic organ prolapse in women. Cochrane Database Syst Rev 2004;(4):CD004014.
- Altman D, et al; Nordic Transvaginal Mesh Group. N Engl J Med 2011;364:1826-1836.
- Maher C, et al. Cochrane Database Syst Rev 2013;4: CD004014.
- Karram M, Maher C. Int Urogynecol J 2013;24:1835-1841.
- Brubaker L, et al. Obstet Gynecol 2008;112:49-55.
- Nygaard I, et al. JAMA 2013;309:2016-2024.
- Ward K, Hilton P; United Kingdom and Ireland Tension-free Vaginal Tape Trial Group. BMJ 2002;325:67.
- Ogah J, et al. Cochrane Database Syst Rev 2009;4:
CD006375. - Richter HE, et al; Urinary Incontinence Treatment Network. N Engl J Med 2010;362:2066-2076.
- Nilsson CG, et al. Int Urogynecol J Pelvic Floor Dysfunct 2008;19:1043-1047.
- Liapis A, et al. Int Urogynecol J Pelvic Floor Dysfunct 2008;19:1509-1512.
- The American College of Obstetricians and Gynecologists. ACOG committee opinion #513. Vaginal placement of synthetic mesh for pelvic organ prolapse. Available at: www.acog.org/~/media/Committee%20Opinions/Committee%20on%20Gynecologic%20Practice/co513.pdf?dmc=1&ts=20130402T1134140198. Accessed Jan. 2, 2014.
- American Urogynecologic Society. Informed Consent Toolkit. April 2012. Available at: www.augs.org/p/cm/ld/fid=174. Accessed Jan. 2, 2014.
- American Urogynecologic Society's Guidelines Development Committee. Female Pelvic Med Reconstr Surg 2013;19:62-65.
- American Urogynecologic Society's Guidelines Development Committee. Female Pelvic Med Reconstr Surg. 2012;18:194-197.
- American Urogynecologic Society. Position statement on Restriction of Surgical Options for Pelvic Floor Disorders. March 2013. Available at: www.augs.org/p/cm/ld/fid=202. Accessed Jan. 2, 2014.
- Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction Mesh Midurethral Slings for Stress Urinary Incontinence. January 2014. Available at: www.sufuorg.com/News/Announcements/SUFU-and-AUGS-Release-Position-Statement-on-Mesh-M.aspx. Accessed Jan. 10, 2014.
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