Achieving efficient anti-adhesion in re-mediastinoscopy: an experimental study in rats

Re-mediastinoscopy can be a difficult procedure due to fibrosis in the mediastinum. We have investigated the effect of an anti-adhesive barrier agent "hylan B gel" on the formation of adhesions after dissection in the superior mediastinum in a rat model.

The study was conducted in 70 male Sprague-Dawley rats weighing 300 g. The strap muscles were divided by a midline cervical incision. The anterior and lateral aspects of the trachea were dissected to the level of the carina. Hylan B gel (Sepragel Sinus, Genzyme Company, Redgefield, NJ, USA) was used to create an anti-adhesive barrier. The rats who were subjected to surgery were sacrificed on postoperative days 14 and 28. All rats were previously divided into 5 groups: Sham group (n = 10); Group 1 (n = 15) surgery alone, sacrificed on day 14; Group 2 (n = 15) surgery and Sepragel, sacrificed on day 14; Group 3 (n = 15) surgery alone, sacrificed on day 28; Group 4 (n = 15) surgery and Sepragel, sacrificed on day 28. Histopathological analysis was performed to study the effect of the anti-adhesive agent. Scores were calculated based on collagen fibrosis, fibroblasts, granulation tissue, muscle alterations/inflammation, histiocytes, mononuclear giant cells, inflammation and vascular proliferation.

Collagen fibrosis and fibroblast scores, which represent adhesions, were significantly higher in Groups 1, 2, 3, 4 than in the Sham group ( P < 0.01). The degree of adhesions on day 14 was found to be higher in Group 1 compared to Group 2 ( P < 0.01). Adhesions on day 28 were higher in Group 3 compared to Group 4 ( P < 0.01). There were no differences between groups with regard to foreign body reactions ( P > 0.05).

Adhesions causing technical difficulty during re-mediastinoscopy can be reduced by the application of anti-adhesive agents during the primary procedure.