Pelvic organ prolapse (POP) is a common occurrence over the course of a woman’s lifetime, especially in parous women (up to 50% of women who have given birth).1 The anterior vaginal wall is the most common site of POP and has the highest recurrence rate of up to 70%.2 The risk of developing POP increases with age, obesity, White race, family history, and prior pelvic surgery, such as hysterectomy. It affects more than 3 million women in the United States alone, often negatively impacting sexual function and overall quality of life.3,4
Because women are living longer than ever before and are more active in their senior years, a long-lasting, durable surgical repair is desirable, if not necessary. To be cost-effective and to avoid general anesthesia, the surgical approach ideally should be vaginal.
Biologic and synthetic grafts to augment transvaginal repair traditionally are used to improve on the well-recognized high failure rate of native-tissue repair that is often seen at both short-term and medium-term follow-up.5 The failure rate is commonly referenced as 30% to 40% at 2-year follow-up and 61% to 70% at 5-year follow-up, well-established by the results of the OPTIMAL randomized clinical trial.6 The more recent Descent trial likewise demonstrates a higher failure rate of native-tissue repair versus transvaginal mesh repair at a shorter term of 30 to 42 months.7 Furthermore, the use of permanent versus absorbable suture in suspension of the vaginal apex is associated with lower short-term failure rates.8
Despite this Level I evidence that demonstrates a clear advantage for obtaining a longer or more durable repair with permanent materials, native-tissue repairs with absorbable suture are still performed routinely. Since the US Food and Drug Administration (FDA) ordered that the use of transvaginal surgical mesh augmentation for pelvic reconstructive surgery be discontinued, it is more important than ever to explore evolving alternative native-tissue augmentation repair techniques that hopefully can preserve the advantages and merits of vaginal surgery and achieve longer durability.9
Biologic graft augmentation use in transvaginal reconstruction
All biologic grafts, including allografts derived from human tissue and xenografts derived from animal tissue, are acellular constructs composed of extracellular matrix (ECM) that acts as scaffolding for the host tissue. The ECM is predominantly composed of collagen (types I and III) and noncollagenous fibronectin, laminin, and glycosaminoglycans in various amounts depending on the source tissue. The 3D presentation of ECM’s complex molecules allows for rapid repopulation of host cells and revascularization with eventual regeneration.
Once a biologic graft is placed surgically, the body’s response to the scaffold ECM mimics the normal wound-healing process, beginning with fibrin-rich matrix hemostasis and the subsequent innate immune response of neutrophil and M1 macrophage infiltration. M1 macrophages are proinflammatory and clear cellular debris and begin the process of graft scaffold degradation. The host tissue then begins the process of remodeling through pro-remodeling M2 macrophages and stem cell recruitment, proliferation, and differentiation.10 As the biologic graft provides initial structure and strength for pelvic repairs, the ideal ECM scaffold would not degrade before the host is able to fully undergo regeneration and maintain its structure and strength.
Biologic grafts differ in source (allograft or xenograft), type (pericardium, dermis, or bladder), developmental stage (fetal or adult), decellularization processing, and sterilization techniques. These 5 aspects determine the distinct 3D ECM scaffold structure, strength, and longevity. If the ECM scaffold is damaged or retains noncollagenous proteins during the preparation process, an inflammatory response is triggered in which the graft is degraded, resorbed, and replaced with scar tissue. Furthermore, certain processing techniques aimed at extending the ECM’s durability—that is, cross-linking collagen—results in the foreign body response in which there is no vascular infiltration or cellular penetration of the graft and a collagen capsule is created around the empty matrix.11 To avoid resorption or encapsulation of the graft, the ECM scaffolds of biologic grafts must be optimized to induce regeneration.
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