[Effect of hyaluronic acid on ureteropyelic anastomosis healing. Experimental study]

Ureteropyelic obstruction is the most frequent congenital cause of obstructive uropathy in the newborn. Its repair is based on surgical procedures and has a very high rate of relapse of secondary stenosis to fibrosis (5-12%) in open repair and 10-20% in endo-urological pyeloplasties. Hyaluronic acid has demonstrated therapeutic utility in modulating the healing process and its effect in scar formation from ureteropyelic anastomosis is determined.

An experimental, controlled, comparative, double blind study was performed. Sample n = 20 per protocol with d = 26%, alpha = 0.05, beta = 0.80. Two groups of Wistar rats, 4 months of age and weighing between 250 and 350 g, were used. Under general anesthesia, Vision 12 x was used and bevel section was realized in the left ureteropyelic union and end-to-end anastomosis with Vicryl 7-0. Experimental group was treated with 25 microg of hyaluronic acid and group B was treated with placebo. The rats were reoperated on the 15th day and adherences in cavity were quantified. To quantify the degree of fibrosis, samples of ureteropyelic anastomosis tissue were dyed with Masson Trichrome and observed microscopically. Inferential statistics were used with a = 0.05.

Macroscopic: there were adherences in 75 % of group A and 90 % of the group B (p >0.05). Microscopic: anastomotic fibrosis in group A (534 +/- 292 micro) was significantly lower (p = 0.043) than that of group B (728 +/- 295 micro).

Hyaluronic acid plays a role in diminishing the formation of fibrosis from ureteropyelic anastomosis in an animal model.