Transvaginal mesh, also known as vaginal mesh implant, is a net-like surgical tool that is used to treat pelvic organ prolapse (POP) and stress urinary incontinence (SUI) among female patients. The surgical mesh is placed transvaginally to reconstruct weakened pelvic muscle walls and to support the urethra or bladder. A number of mesh materials with varying absorbability has been explored to maximise the biocompatibility as well as the repair efficacy of mesh. Depending on the target vaginal space, the application of transvaginal mesh differs in terms of mesh shape, surgical incision and the position of mesh. Since 2019, transvaginal mesh has been banned by the US Food and Drug Administration (FDA) due to the high prevalence of complications, including mesh erosion, pain and pelvic infection. Complications may arise from concomitant surgery and inappropriate surgical techniques, while they can also be prevented with uterus preservation. Transvaginal mesh was once used widely for nearly 25% of prolapse interventions until the FDA ban, yet approximately 1 out of 15 patients required a mesh removal in the past decade.
Classification Based on how transvaginal mesh reacts inside the patient’s body, the implant is classified into 4 subtypes:
“Non-absorbable synthetic mesh” is made from synthetic materials, for example, plastic, polyester or polypropylene. It is most preferred by surgeons because of its compatibility with connective tissues, which increases repair efficacy and reduces the rate of infection. It can be further classified based on pore size to determine risk of infection and mesh exposure. Meshes with pore sizes larger than 75μm are most commonly used for repair as they aid tissue incorporation and lower infection risk. “Absorbable synthetic mesh” is made from synthetic materials, such as polyglactin and polyglycolic, and can be absorbed by the body. Tissues nearby will then grow at the implantation site, strengthening the ligaments in the pelvis region. “Biologic mesh”, also known as graft, is made from natural products derived from disinfected animal tissues, such as tissues from cows and pigs. This mesh subtype only works temporarily as it degrades over time, leading to inconsistent tissue strength and a higher failure rate. It also carries a theoretical transmission risk of infectious disease. “Composite mesh” is made from a combination of the above subtypes. The selection of mesh subtype to be placed in patients requires consideration of patients' preference and risk analysis, including evaluation of recurrence risk and complication risk by surgical personnel.
Medical uses Transvaginal mesh is used to repair symptomatic pelvic organ prolapse that causes pain and discomfort among patients and to treat stress urinary incontinence.
Pelvic organ prolapse (POP) Repair
Transvaginal mesh prevents pelvic organs, such as the bladder, uterus and rectum from sagging into the vagina due to weak pelvic muscles by acting as a hammock underneath. Depending on the organs involved, it can be placed on the anterior, posterior, or top wall of vagina transvaginally. In some special cases of vaginal vault prolapse, the vagina may collapse after the removal of the uterus and a transvaginal mesh can be positioned on top of the vagina to fix it in place.
Stress Urinary Incontinence (SUI) Repair Transvaginal mesh, also called bladder sling in this case, holds up the urethra when pelvic muscles weaken. This prevents bladder leakage during physical movements that increases bladder pressure. Compared to traditional native tissue repair surgery, transvaginal mesh, especially when placed in anterior vaginal area, has improved POP repair outcomes but similar SUI repair outcomes. Advantages over native tissue repair are mainly associated with improved surgical procedures, for example, simpler and less invasive procedures, higher reproducibility of techniques and durability. However, transvaginal mesh remains as a refuted method due to its adverse complications.
Technique
As pelvic organ prolapse and stress urinary incontinence can be present separately or simultaneously, surgical mesh is implanted into vesicovaginal and rectovaginal region through the vaginal route in different approaches, to manage patients’ condition properly.
Pelvic organ prolapse (POP) surgery The goal of POP repair with transvaginal mesh is to increase longevity in patients by reconstructing organ position and preventing pelvic organs from bulging into the vagina. Generally, the position and incisions for transvaginal mesh are determined by the corresponding pelvic muscle defect, which differs from patient to patient. The implantation usually starts with anterior colpotomy, which is an incision on the anterior vaginal wall to assess the vesicovaginal space in front of the vagina. For patients who have undergone hysterectomy or will be preserving their uterus, only longitudinal anterior incision can be performed. For patients who are also receiving a concomitant hysterectomy, an anterior colpotomy, a Cross-T-shaped incision that cuts around the cervix, or a single incision around the cervix and across the vagina will be performed.
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