JUSTIFICATION AND EXPERIENCE IN USING THE CLASSIFICATION OF APPENDIX LOCATIONS AND THE ALGORITHM FOR ITS DETECTION DURING TRANSABDOMINAL ULTRASOUND EXAMINATION IN PATIENTS WITH SUSPECTED ACUTE APPENDICITIS

Objective. To develop, justify, and test an ultrasound classification of appendix locations in the abdominal cavity and a new algorithm for identifying the appendix during ultrasound examination in patients with suspected acute appendicitis (AA). Material and Methods. From December 2023 to July 2024, 114 patients with suspected AA, admitted as emergency cases were examined. The patients underwent ultrasound examination of the right iliac region. To locate and fully visualize the appendix, we used our developed algorithm, which includes determining the position of the cecum and sequentially examining three areas around the cecum, along with special techniques to improve appendix visualization. After the examination, the following data were recorded: the location of the cecum, the location of the appendix, and the degree of its visualization. To determine the position of the appendix in the abdominal cavity our developed classification was used. When the cecum was located in the iliac fossa, the following positions of the appendix were distinguished: "on the muscle," "muscle-small pelvis," "medial," "lateral," and "rolled-up paracecal" positions. When the cecum was located along the right lateral canal, the positions of the appendix were identified as "infracecal," "medial," and "lateral." In the case of a pelvic location of the cecum, the appendix positions were classified as "paravascular," "subcecal," and "medial." Results. During ultrasound examination, the appendix was found in 91 (79.8%) patients, while in 23 (20.1%) patients, it was not detected. The most common location of the cecum was the right iliac region, where the most frequent appendix positions were "on the muscle," "muscle-small pelvis" and "rolled-up paracecal" positions, accounting for 63 (55.3%) cases in total. Out of 17 cases of pelvic location of the cecum, the appendix was not found in nine (52.9%) cases. Complete visualization of the appendix was achieved in 50% of cases. "The pelvic elevation" technique improved appendix visualization in 23.7% of cases. "The shifting of the appendix onto the muscle" technique improved visualization in 87% of cases. "The controlled rotation onto the left side" technique proved effective in 71% of cases. Conclusions. The proposed classification is justified from the perspective of ultrasound visualization of the appendix. The key distinguishing features of the proposed appendix identification algorithm are the changes in the physician’s approach depending on the location of the cecum and appendix, and the targeted shifting of the cecum and small intestine in order to improve appendix visualization. The techniques to enhance appendix visualization used in the algorithm have demonstrated their effectiveness in practice. In half of the cases, incomplete visualization of the appendix is noted, which reduces the diagnostic significance of ultrasound in suspected acute appendicitis.