To create a method of two-stage repair of high unformed conglomerate delimited debilitating jejunal fistulas via posterolateral laparotomy with low risk of surgical complications. Methodology and treatment outcomes were analyzed in 37 patients with unformed conglomerate high debilitating delimited jejunal fistulas. Of these, 22 patients underwent one-stage treatment through 2 converging incisions and/or two-stage treatment through anterolateral access. They made up a control group. Fifteen patients in the main group underwent two-stage treatment via posterolateral left-sided laparotomy with unilateral disconnection of jejunum with fistula. In most patients of both groups, fistulas complicated surgery for acute adhesive intestinal obstruction. Topography of adhesions that caused acute intestinal obstruction in both groups was studied in 172 other patients. Identical jejunal fistulas and two different surgical approaches made it possible to consider our groups representative. Two-stage treatment via posterolateral left-sided laparotomy reduced mortality from 63.6±10.2% to 20.0±10.3% (t=11.8; p<0.001). This approach simplified intraoperative diagnostics that became more informative. Posterolateral access increased the quality of anastomosis and safety of viscerolysis. A new two-stage approach with posterolateral left-sided laparotomy allowed atraumatic imposing of inter-intestinal anastomosis with proximal disconnection of jejunal fistula. This exclusion turns the fistula into analogue of the definitive Meidl's jejunostomy, unloads the intestinal anastomosis and increases the quality of suture. New strategy reduced the risk of complications and mortality.