Use of medroxyprogesterone acetate in the prevention of postoperative adhesions

Objectives: To evaluate the efficacy of a commonly used progestogen, medroxyprogesterone acetate (MPA), in the prevention of postoperative adhesion formation. Design: A double-blind, controlled study evaluated the efficacy of MPA to reduce postoperative adhesion formation and compared it with other adjuvants and controls in a rat model. Setting: Animal Care Facility of an academic research setting. Subjects: Seventy-five Sprague-Dawley female rats randomly divided into five groups. Interventions: Three weeks before surgery, the animals from each group were administered an IM injection of one of the following regimens: [1] 15 mg MPA; [2] both 15 mg MPA and 0.75 mg leuprolide acetate (LA); [3] 0.75 LA; or [4] and [5] comparable volumes of sterile saline. A standardized surgical trauma was inflicted in all animals. Before abdominal closure, 2 mt of Ringer's Lactate was instilled in the abdominal cavity of all groups except group 5 (controls). Three weeks after surgery, the rats were killed and the adhesions were scored on a scale of 0 to 3 according to their size, thickness, and vascularity. Main Outcome Measure: Postoperative adhesions. Results: The preoperative administration of MPA resulted in the least number and the least severe adhesions. The combination of LA and MPA did not reduce postoperative adhesion formation. Both Ringer's Lactate and LA reduced postoperative adhesions but not to the same extent as MPA. Conclusion: The preoperative administration of MPA in our laboratory animal model results in the most significant reduction of postoperative adhesion formation. This action of MPA may be mediated by the induction of both a progestational and a hypoestrogenemic milieu. However, the ultimate role of MPA in a clinical situation requires further investigation.