Introduction. The small size of the bladder plate is a poor prognostic sign for successful treatment of exstrophy. Primary closure in newborns and infants with microcystisis often accompanied by complications and relapses; there for, the approach to the treatment of this group of patients requires a more detailed analysis.

The aim of the study. Identify advantages and disadvantages of delayed primary closure surgery in patients with bladder exstrophy and microcystis.

Materials and methods. During the period from 1994 to 2020, 265 children with bladder exstrophy were subjected to surgery, 123 patients were newborns. There were 37 children with microcystis (bladders plate <3 cm). In 30 children, primary closure was performed at the newborn age. Seven patients with microcystis were subjected to everyday manual and mechanical stretching of the bladder and injections of botulinotoxin type A into the bladder plate (2-3 times) for 1-2 years. In 5 children the size of the bladder plate was increased from 3 cm to 6 cm, they were underwenteded delayed primary closure at the age of 1-2 years, supplemented by ureteroneoimplantation, bladder neck reconstruction, with bilateral osteotomy.

Results. Complications of primary closure in patients operated on during the neonatal period (30) such as relapse of the exstrophywere observed in 10 patients (33.3%) and partial wound dehiscence in 3 children (10%). In patients with microcystis that underwent delayed primary closure after stretching the bladder, there was no relapse of exstrophy, and growth of the bladder was observed.

Conclusions. In our opinion, delayed primary closure of the bladder in children with microcystis after mechanical stretching of the bladder plate in combination with injections of botulinum toxin type A into the detrusor can improve the results of correction of exstrophy.