Морфологічне обгрунтування ультразвукових критеріїв гострої непрохідності кишечника механічного ґенезу

Abstract

Diagnosis of acute bowel obstruction is based on the data of radiological examination methods – radiography, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). Among these, the most accessible and cost-effective are radiography and ultrasound examination. For a surgeon, it is essential to establish not only the diagnosis of acute bowel obstruction (ABO) but also, more importantly, to determine its origin – mechanical or dynamic. The origin of the ileus directly influences the choice of treatment strategy. That is why it is necessary to have an accessible and highly informative objective diagnostic method. Ultrasound exami-nation is one of such methods. However, the absence of reliable and substantiated criteria for determining the ABO with this method limits its use.Purpose – substantiate the ultrasound features of mechanical ABO based on the dynamic changes in the morphological data of the bowel wall.Materials and methods. Mechanical ileus was modeled in 22 white rats. The dynamic changes in the histological structure of the bowel wall located above the site of obstruction were studied at 12, 24, and 48 hours. The control group consisted of 4 animals that only underwent laparotomy. In the obtained biopsies, we studied the indicators that changed as the ABO progressed, forming features that can be detected by ultrasound. Quantitative evaluation of the mucosal, submucosal, and muscular layers of the small bowel wall was carried out morphometrically using the OlympusBX-41 eyepiece, the AM9-2 ocular micrometer, and the Avtandilov’s eyepiece graticule.In the clinic, the frequency of ultrasound criteria was studied in 53 patients with confirmed tumor-related small bowel obstruction. The patients’ ages ranged from 21 to 82 years (52±1.3). There were 24 men (45.3%) and 29 women (54.7%). For diagnosing ileus, the PhilipsHD-11XE and Siemens Sonoline Prima ultrasound imaging systems, as well as the FS-500DDR-3 radiography machine, were used.Results. The results of the study showed that in mechanical ileus, three main conse-cutive stages occur: first, the expansion of the bowel lumen above the site of obstruction; second, sequestration of fluid in the lumen; and third, purulent inflammation of the bowel wall accompanied by an exudative component. The latter leads to swelling of the layers of the bowel wall and its enlargement, which can be visualized by ultrasound, especially the mucosal layer. The longer the mechanical ileus persists, the more pronounced the purulent inflammation of the bowel wall becomes, and it also transitions to the serous layer. This results in the reaction of the peritoneal covering and the appearance of fluid between the bowel loops.The morphological changes observed in the bowel wall formed the basis for the ultrasound criteria of the ABO, which were studied in 53 patients with confirmed tumor-related small bowel obstruction, 43 (81.1%) of whom were hospitalized within 24 hours of the clinical manifestation of the disease. Upon admission, these patients underwent sequential diagnostic ultrasound of the abdominal organs followed by X-ray.Acute ileus was confirmed by the presence of 82±11.6% of features detected by ultrasound, whereas on radiography, only 18±11.6% of features were found (p<0.005).According to the dynamic changes in the histological structure of the bowel wall, which were characteristic of each stage of mechanical ileus formation, we believe that the objective ultrasound criteria for the ABO are the following: expansion of the bowel lumen, visualization of fluid in the lumen, the mucosal relief in the form of Kerckring’s folds, changes in bowel peristalsis, and the presence of free fluid between the bowel loops.Based on the number of features of small bowel ileus detected by ultrasound, it can be assumed that each of them corresponds to one of the stages of disease progression, as confirmed by the results of the study. By X-ray, some features of ileus could not be detected in the patients.Conclusions. The experiment has demonstrated that mechanical ileus has conse-cutive stages of development, accompanied by changes in the histological structure of the bowel wall located above the site of obstruction. The ultrasound features of mechanical ABO are based on the dynamic changes in the morphology of the bowel wall.The study proved that the longer the ileus persists, the more pathological changes occur in the bowel wall, which can be visualized by ultrasound.The ultrasound method for diagnosing acute mechanical ileus has an advantage over radiography due to its ability to detect features characteristic of the various stages of disease formation: 82±11.6% of the features of ileus were detected by ultrasound, compared to 18±11.6% detected by radiography (p<0.005).