Surgical mesh is a net-like medical implant, often called pelvic or bladder mesh, used primarily in gynecological and urological surgeries to reinforce weakened tissue. This device is designed to provide long-term support for organs that have shifted from their natural position due to pelvic floor disorders. It is constructed from either synthetic polymers or, less commonly, biological materials derived from animal tissue. This article details the composition of surgical mesh, its intended use, the surgical procedures for its placement, and the significant adverse events that have led to regulatory changes.
Defining Surgical Mesh and Its Purpose
Surgical mesh is a permanent implant, typically composed of non-absorbable, knitted polypropylene. This synthetic material is chosen for its strength and durability, acting as an internal scaffolding to support the body’s natural structure. The porous, net-like design allows the patient’s own connective tissue to eventually grow into the mesh, creating a reinforced layer of support.
The device is designed to treat two main conditions: Stress Urinary Incontinence (SUI) and Pelvic Organ Prolapse (POP). SUI involves the involuntary leakage of urine during physical activities like coughing, sneezing, or exercising, which is caused by a weakened urethra support. For SUI, the mesh is implanted as a sling or hammock to support the urethra or bladder neck, preventing the leakage.
POP occurs when the muscles and ligaments supporting the pelvic organs become stretched or weakened, causing organs like the bladder, uterus, or rectum to drop or bulge into the vagina. When used for POP repair, the mesh acts as a graft to reinforce the vaginal wall and restore the organs to their correct anatomical position. While synthetic mesh is permanent, some manufacturers have offered biological mesh derived from animal tissue, which is designed to be absorbed by the body over time.
The Surgical Placement Process
The implantation of pelvic mesh is a minimally invasive surgical procedure. The specific surgical route depends on the condition being treated and the surgeon’s preference. For SUI, the mesh is inserted as a mid-urethral sling, typically through a small incision in the vagina and two incisions in the lower abdomen or groin. This sling acts to elevate and support the urethra, a procedure known for its relatively quick recovery time.
For POP repair, the mesh was historically placed using a transvaginal route, meaning the surgeon accessed the pelvic floor through an incision in the vaginal wall. In this method, the mesh graft was intended to reinforce the weakened tissue holding the prolapsed organ in place.
An alternative method is the abdominal route, often performed as a sacrocolpopexy, which is used to support the top of the vagina or uterus. This abdominal approach is typically done laparoscopically or robotically, involving several small incisions in the abdomen to place and secure the mesh.
Understanding Adverse Events
Despite its intended benefits, the use of surgical mesh for pelvic floor repair has been linked to a range of recognized adverse events. One of the most frequently reported complications is mesh erosion, also called exposure, where the mesh material wears through the vaginal wall or other surrounding tissue. This can lead to bleeding, abnormal discharge, and pain during intercourse for both the patient and her partner.
Another serious complication is the development of chronic pain in the pelvic, groin, or leg areas, which can persist for years after the surgery. This pain is often attributed to nerve entrapment or inflammation caused by the foreign material. The material may also contract or shrink over time, leading to further tissue tension and pain.
Infection and chronic inflammation are ongoing concerns, as the body may react to the non-absorbable synthetic material as a foreign body. This foreign body response can cause continuous inflammation, which may not resolve even with antibiotics.
In rare but severe cases, the mesh or the instruments used during placement can perforate or injure nearby organs, such as the bladder, bowel, or major blood vessels. Organ perforation often requires immediate and complex surgical repair.
Regulatory Status and Patient Options
The complications associated with pelvic mesh, particularly those placed transvaginally for POP repair, prompted significant action from the U.S. Food and Drug Administration (FDA). In 2016, the FDA reclassified surgical mesh used for transvaginal POP repair as a high-risk device, known as Class III. This reclassification was based on evidence showing that the benefits of this procedure did not outweigh the risks compared to traditional non-mesh repair.
Following this, the FDA ordered manufacturers to stop the sale and distribution of all surgical mesh products intended for transvaginal POP repair in the U.S. in April 2019. This action did not apply to mesh slings used to treat SUI or mesh used in abdominal POP repair, which remain available.
For patients who have experienced adverse events, treatment options include partial or complete mesh removal surgery, though this can be complex and may not fully resolve symptoms. Non-mesh alternatives are also available for both conditions, such as native tissue repair for POP, which uses the patient’s own ligaments and fascia to provide support.
Women who have had mesh implanted and are not experiencing symptoms should continue with routine follow-up care. Any new or persistent symptoms, such as pain, bleeding, or unusual discharge, should be promptly discussed with a healthcare provider.