The thesis is devoted to solution of current scientific task of urgent surgery of abdominal cavity organs - improvement of results of operative treatment of patients by modernizing methods of diagnostics and operative treatments. The work is based on the analysis of the results of the examination and treatment of 852 patients with atypical course of acute appendicitis (25,3 %) among 3370 patients with acute appendicitis, which were operated at the clinic of the Surgery Department № 2 of Bohomolets National Medical University from 2007 to 2016. Depending on the chosen diagnostics and therapy, the patients with acute atypical appendicitis were divided into two groups: observer group and basic group. The observer group included 423 patients operated during 2007-2010 (1st observation period) for acute appendicitis, using standard approaches of diagnostics and treatment. The basic group included 429 patients who were treated using our upgraded diagnostics and therapy (2nd observation period - 2011-2016). In addition, the work also included a retrospective analysis of the medical history of 3795 patients in order to determine the main factors, which cause an atypical course of acute appendicitis. It was established that the main factors that cause atypical course of acute appendicitis are atypical location of the inflamed appendix, elderly or senile age of patients, heavy background concomitant pathology (immunodeficiency, oncology, etc.). It was determined that at the abnormal location of the inflamed appendix, its retrocecal localization prevails (60,99 %), the pelvic location occurs in 24,1 % of cases. In this group, destructive forms of the disease prevail (92,5 %), which are complicated by different forms of peritonitis (77,7 %). The improved rectal thermocartography method in case of suspected acute pelvic appendicitis was reduced the frequency of gangrenous forms from 33,3 % to 15,2 %, due to a significant reduction of time needed for pre-examination of patients (1,4±0,3 days), and, as a consequence, reduced the periappendicular abscesses with such appendicitis location from 38,9 % to 18,9 %. The use of the proposed method for diagnosis of peritonitis, in cases complicated for clinical verification, allowed to take off the emergency indications for surgical treatment (that is, to avoid unreasonable appendectomy) in 6.3 % of patients with another abdominal organs pathology that could be treated conservatively (mesenteric adenitis, toxic infection, chronic gynecological pathology, etc.), which was found during further dynamic observation and examination. Using improved methods of peritonization of the stump of appendix with destructive forms of acute appendicitis, under conditions of infiltration of the caecum, it was possible to reduce the incidence of purulent complications by 13,04 % and expand the indications for laparoscopic appendectomy, that significantly reduces the time a patient spends in a hospital. The introduction of advanced technologies for diagnostics and surgical treatment atypical forms of acute appendicitis has made it possible to reduce the percentage of discrepancies in clinical and pathohistological diagnoses by 13,3 % and reduced the incidence of complications in the early postoperative period from 9,9 to 3,5 %, in the long term - from 14,1 to 1,2 %.
