This study was conducted as a retrospective cohort study in a single institution. A database of patients who underwent cooperative surgery due to obstetrics and gynecological diseases at Pusan National University Yangsan Hospital between December 2008 and August 2020 was obtained, and through database classification and medical record analysis, patients who underwent colorectal resection due to gynecological malignancies were finally selected as the subjects. Cases of malignancies that originated from other organs than female reproductive organs (Krukenberg tumor, metastasis of colon cancer, etc.) or benign gynecological diseases (endometriosis, female pelvic inflammatory disease, rectovaginal fistula, etc.), cases where any kind of enterostomy was performed at the time of the first surgery, cases where only enterectomy was performed excluding the colon and the rectum (appendectomy only, small intestine resection, etc.), and cases where there was no anastomotic site because only primary repair was performed were excluded (Fig. 1).
Among the medical records collected, the records of the first medical examination at the department of obstetrics and gynecology or surgery, progress records, consultation request forms, operative notes, pre-anesthesia evaluation tables, anesthesia records, and hospitalized nursing records were analyzed. Examination results, histopathologic examination results, and imagery interpretation reports were also included. Referring to previous studies, observation items and variables necessary to analyze risk factors were selected [1, 4–6]. As patient factors, age, height, weight, body mass index (BMI), whether diabetic, whether smoking, steroid administration history, and American Society of Anesthesiology (ASA) classifications were included. Diagnosis and disease stages were determined according to the standards of the International Federation of Gynecology and Obstetrics (FIGO). Preoperative and postoperative hemoglobin (Hb) levels, preoperative albumin (Alb) levels, and preoperative levels of CA125, CA19-9, and SCC, which are the most widely used tumor markers in gynecological malignancies, were investigated. The most recent examination results before entering the operating room were collected as preoperative examination results, and the results of the examination conducted for the first time after surgery were collected as postoperative examination results. As preoperative status-related factors, whether the relevant disease was diagnosed for the first time or had recurred, and whether chemotherapy and radiation therapy were carried out before surgery were included, and as intraoperative status-related factors, the total operation time, estimated blood loss (EBL), whether blood was transfused, and transfusion volume were included. As surgery-related factors, whether the surgery was emergency surgery, whether laparotomy was performed, types of surgery, whether an additional enterectomy accompanied, the distance from the anal verge (AV) to the anastomotic site, and anastomosis method (whether an automatic stapler was used) were investigated. In addition, whether the obstetrics and gynecology department requested cooperation from the department of surgery before the surgery was investigated and included in the variables.
Whether complications occurred after surgery was investigated to find out the frequencies of surgical wound infection, anastomotic leakage, anastomotic site infection, intraabdominal infection, cardiovascular complications, respiratory complications, and urinary complications separately. Whether anastomotic leakage occurred was judged by putting together medical records and examination results using the diagnostic criterion set as corresponding to at least one of 1) cases where amylase and lipase were detected in the intraabdominal drainage tube contents in amounts exceeding the reference values, 2) cases where findings indicating anastomotic leakage such as fluid retention around the anastomotic site were identified in radiological findings such as computed tomography (CT)[5, 7]. Cases that did not meet this diagnostic criterion were classified as anastomotic site infection, and intraabdominal inflammations and infection of areas other than anastomotic sites were separately classified as intraabdominal infection. In order to explore and analyze risk factors for anastomotic leakage, the study subjects were divided into two groups: patients in whom anastomotic leakage occurred and patients in whom no anastomotic leakage occurred, and statistical analysis was attempted.
All statistical analyses were conducted using IBM SPSS Statistics version 25 (SPSS Inc, Chicago, IL, USA). Some scale variables were converted into nominal variables through grouping and analyzed thereafter. Chi-square tests and Fisher's exact tests were used for nominal variables and Mann-Whitney's U tests were used for scale variables. The P-value to determine statistical significance was set to below 0.05.
This study is a retrospective cohort study conducted through medical record analysis and was exempted from review by the Institutional Review Board (IRB) of Pusan National University Yangsan Hospital. (IRB No. 05-2020-203). Written informed consent forms concerning cooperative colorectal resection were obtained for publication of the study.