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What does PAC stand for?

PAC stands for Peritoneal adherent cells

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Ceana H. Nezhat, MD, Vadim V. Morozov, MD, Daniel S. Seidman, MD INTRODUCTION Peritoneal adhesions following pelvic and abdominal surgery are a frequent cause of intestinal obstruction, reduced fertility, and pelvic pain. In gynecology, adhesion formation at the vaginal cuff and pelvic sidewall frequently involves bowel, omentum, and adnexa. This may result in pelvic pain, dyspareunia, small bowel obstruction, and residual ovary syndrome when salpingo-oophorectomy is not performed. Adhesions were identified as the primary cause of chronic pelvic pain in 13-26% of females. In many surveys of postoperative bowel obstruction, abdominal surgery was found to be the leading cause of adhesion formation. Intra-abdominal adhesions between the previous abdominal scar and the underlying viscera are a common consequence of laparotomy. Patients undergoing laparoscopy after a previous laparotomy should be considered at risk for the presence of adhesions between the old scar and the underlying viscous, such as bowel or omentum. It has been reported that after laparotomy, 68-82% of patients will have intra-abdominal adhesions. Patients with midline abdominal incisions had more adhesions (59%) than did those with Pfannenstiel incisions (27%). Patients with midline incisions done for gynecologic indications had more adhesions (42%) than did patients with any abdominal incisions performed for obstetric indications (22%). The type of incision did not affect the presence of adhesions in patients with previous obstetric operations. Adhesions to the bowel were more common after midline incisions above the umbilicus. Twenty-one women had direct injury to adherent omentum and bowel during the laparoscopic procedure. Even more important for laparoscopic surgery is the presence of peri-umbilical adhesions. In most cases, the umbilicus remains the primary site of entry for a variety of laparoscopic procedures. Table 1 demonstrates the incidence of peri-umbilical adhesions following various surgical interventions. Peritoneal adhesions are thought to cause pelvic pain by indirectly inhibiting the motion of involved organs, thereby stretching the smooth muscle of adjacent viscera or the abdominal wall. Sulaiman et al., examined adhesions found in women undergoing laparotomy, most of whom had chronic pelvic pain. Analysis revealed that all adhesions studied had sensory nerve fibers although the location of the adhesion, its size, and its estimated age did not influence the type of nerve fibers found. A recent prospective blinded randomized multicenter trial compared laparoscopic adhesiolysis to diagnostic laparoscopy for the relief of chronic pelvic pain attributed to adhesions. Both groups exhibited significant improvement in their pain and quality of life but there were no differences found between the two groups. This finding in the diagnostic laparoscopy group could be attributed to a possible placebo effect or to the fact that many women were reassured that they had no serious pelvic pathology. In spite of these results, adhesiolysis for pelvic pain should still be considered in cases where dense adhesions between organ systems exist or for situations such as ovarian remnant syndrome. The effect of adhesions on fertility is unquestioned. Caspi and associates reported an inverse relation between the severity of pelvic adhesions and pregnancy rates. After adhesiolysis, pregnancy rates varied according to the extent of adnexal damage and, to a lesser degree, the severity of the adhesions. It has been repeatedly shown that both extent and severity of adhesions are significantly reduced by laparoscopic adhesiolysis. However, the initial extent and severity of adhesions do not predict recurrence. The involved organ, adnexa being most frequent, was shown to be the only predictive factor. Since the development of postoperative adhesions is a major factor in deciding the outcome of fertility-promoting operative procedures, gynecologists should understand the mechanism of their formation, use optimal techniques for adhesiolysis, and apply agents or devices to reduce their development. ADHESION FORMATION Adhesions form when there is damage to the visceral or parietal peritoneum, and the basement membrane of the mesothelial layer is exposed to the surroundings. Causes of peritoneal injury include irritation and damage from infection, ischemia, mechanical trauma, or exposure to various chemicals. This injury induces an inflammatory reaction whereby mast cell breakdown occurs, vascular permeability increases, and a fibrinous exudate is produced. This exudate is then transformed into a fibrin matrix covered with mesenchymal cells, fibroblasts, and macrophages, and enables tissue repair to occur. Although this fibrin matrix is essential for the healing process of normal peritoneum, its dissolution is also necessary so that adhesion formation does not occur. This dissolution is mediated by the fibrinolytic pathway where plasminogen is converted to its active form, plasmin, which then degrades fibrin. Normal fibrinolytic activity usually prevents fibrinous attachments for 72 to 96 hours after surgery. Mesothelial repair occurs within 5 days of trauma and this process of peritoneal healing differs from that of skin as observed by Hertzler. When a peritoneal defect is made, repair is not initiated at the borders of the defect, but rather, the entire surface becomes epithelialized spontaneously. This phenomenon allows small defects to heal as quickly as larger ones. Figure 1. When the fibrinolytic activity of the peritoneum is suppressed, fibrinous adhesions are formed and persist, as collagen deposition and neovascularization occur. The factors that suppress fibrinolytic activity and promote formation of postoperative adhesions are listed in Table 2. Prevention of fibrinolytic suppression can be achieved to a certain extent with microsurgical principles and techniques. The use of magnification, proper handling of tissues, constant irrigation, meticulous hemostasis, and the use of microsurgical instruments and fine nonreactive sutures are of utmost importance. Peritoneal reapproximation, which was previously advocated, is now no longer recommended. After peritoneal tissue is resected, natural healing is associated with less adhesion formation than occurs after reapproximation with staples or sutures, as demonstrated by McDonald in a rabbit model. In the past, fertility-promoting operations done by laparotomy were often followed by reformation of adhesions and the development of new adhesions even when proper microsurgical techniques were employed. Reformation of adhesions is found at 37 to 72% of operative sites, and 51% of patients develop new adhesions after reproductive procedures by laparotomy. Several animal and clinical studies compared the formation of postoperative adhesions after fertility-promoting operations by laparoscopy and laparotomy. With...