This retrospective study enrolled all patients who had undergone gynecologic laparoscopic surgery at Huazhong University of Science and Technology Union Shenzhen Hospital (Shenzhen, China) between January 2005 and October 2021. The inclusion criteria were as follows: (1) age above 18 years; (2) underwent gynecologic laparoscopic surgery; (3) having been initially assessed in other departments through laparoscopy but later diagnosed with a gynecological disease, and transferred to the gynecological department for surgery. The exclusion criteria were: (1) combined with other surgeries; (2) open surgery; (3) incomplete data; (4) cases involving only laparoscopy or biopsy subsequent surgery, primarily for advanced ovarian cancer that was deemed inoperable; (5) simultaneous performance of other non-gynecological surgeries in different departments. This study was approved by the Medical Ethics Committee of Huazhong University of Science and Technology Union Shenzhen Hospital (No. LW-2023-005) and informed consent were obtained. In adherence to the guidelines set forth by the journal, our data will be made available for independent analysis by a specifically chosen team, as determined by the Editorial Team. This will serve the purpose of conducting additional data analysis or facilitating the reproducibility of our study in other research centers, if such request is made.

The study collected demographic and clinical data from medical records, including age, BMI, history of prior abdominal surgery, year of surgery, type of surgery, procedural characteristics, length of hospital stay, minor complications, and major complications. Age was divided into three groups: $\le$30 years, 31–60 years, and $>$60 years. This study included all laparoscopic procedures performed between January 2005 and October 2021; complex surgeries were carried out by 12 experienced specialists, including two consultants and 10 associate consultants. All operations followed the established guidelines and were followed up for at least five months based on the patients’ conditions. Retrospective data indicated changes in the doctors performing gynecological laparoscopic surgery over a span of more than 16 years, with an overall improvement in the competence level of many doctors. The study categorized the year of surgery into two periods: 2005–2011 and 2012–2021. It is important to note that our hospital has been performing laparoscopic surgery since 2001, and complete datasets for patients were available from 2005 onwards. Complications were defined as any adverse events that occurred during the operation or within one week post-operation. The gynecologic laparoscopic surgeries were classified into four types: (1) adnexal surgery, (2) myomectomy or surgery for other uterine lesions (including cesarean scar pregnancy), (3) laparoscopically assisted vaginal hysterectomy (LAVH) or total laparoscopic hysterectomy (TLH), and (4) surgery for malignancy (cervical cancer underwent laparoscopic radical hysterectomy combined with pelvic lymph node dissection, and endometrial cancer underwent total laparoscopic hysterectomy combined with pelvic and para-aortic lymphadenectomy).

Complications arising from laparoscopy were categorized as major and minor. Major complications were defined as those occurring during laparoscopy or the postoperative period that necessitated additional intervention, such as laparoscopy or laparotomy. These included injuries to the intestine, urinary bladder, ureter, or major blood vessels, significant bleeding (with a volume exceeding 600 mL within 24 hours of the perioperative period), severe infective complications, and pulmonary edema. Minor complications encompassed mild bleeding or infection, fever, nerve damage, abdominal wall hematoma, urinary tract infection or retention, paralytic ileus, subcutaneous emphysema, genital edema, uterine perforation, and pain of unknown origin. Postoperative evaluations were conducted for all patients. Diagnostic criteria for serious infective complications included: (1) signs of infection, such as fever; (2) concurrent organ dysfunction, such as hypotension (referred to as shock blood pressure, with systolic blood pressure below 90 mmHg and diastolic blood pressure below 60 mmHg); (3) alterations in mental state; (4) respiratory failure accompanied by rapid breathing; and (5) reduced urine output, indicating poor kidney blood supply and impaired urine excretion [10, 11].

The analyses were conducted using SPSS 26.0 (SPSS, Inc., Chicago, IL, USA). Statistical significance was defined as p-values 0.05. Normally distributed continuous data were presented as mean $\pm$ standard deviation and compared between groups using Student’s t-test. Skewed distributed continuous data were presented as median (range) and compared using the Mann-Whitney U test. Categorical data were described as n (%) and compared between groups using the chi-squared test. Logistic regression models were constructed to identify factors associated with major and minor complications. Adjusted odds ratios (aORs) and their 95% confidence intervals (95% CIs) were calculated. The final regression model was obtained using stepwise regression of factors with p 0.05 in the univariate analysis. Statistical significance was defined as p 0.05.

A previous meta-analysis of 27 prospective randomized clinical trials demonstrated that laparoscopic surgery was associated with several benefits compared to laparotomy, including a significant reduction in pain, with an 80% decrease in the rate of surgical site infection. Additionally, patients who underwent laparoscopic surgery experienced a shorter hospital stay by two days and a faster return to physical activity by two weeks. Furthermore, laparoscopic surgery was found to reduce the rate of postoperative adhesions by 60% when compared to laparotomy [12].

However, gynecologic laparoscopic surgery carries a risk of complications. In this study, the incidence of minor complications was found to be 4.64%, which aligns with previous studies [3, 4, 13]. The rate of major complications was only 0.51%, lower than what has been reported by others [2, 3]. One possible explanation for this discrepancy is that the majority of patients in our study underwent adnexal surgery or myomectomy, which are relatively less complex procedures. Notably, the incidence of complications was higher during the period of 2005–2011 compared to 2012–2021, suggesting a progressive improvement in the skill level of our surgeons over time. This finding is consistent with previous research indicating that the surgeon’s annual case load influences the rate of complications [8].

In this study, the main factors associated with major complications were older age, prior abdominal surgery, and type of surgical procedure (which was used as an indicator of surgical complexity). Elderly patients, who often experience tissue degeneration and compromised visceral function, along with a history of multiple previous surgeries, face challenges in tissue separation during surgical procedures. These difficulties can lead to an increased risk of bleeding and potential damage to surrounding organs. The above findings agree well with prior research [3, 6, 8]. Other studies have also suggested that operation type, surgical complexity and degree of pelvic adhesions may affect the incidence of complications [13, 14, 15, 16, 17].

In this study, the primary factors associated with major complications were older advanced age, previous abdominal surgery, and the type of surgical procedure, which served as an indicator of surgical complexity. These findings align with previous research studies [3, 6, 8]. Additionally, other studies have indicated that the type of operation, surgical complexity, and the extent of pelvic adhesions may influence the occurrence of complications [13, 14, 15, 16, 17].

Gynecologic laparoscopic procedures have been identified as the cause of over half of all iatrogenic injuries to the ureters [18]. The incidence rate of gastrointestinal injury during gynecologic laparoscopic surgery has been estimated to range from 0.13% to 1% [19, 20]. Among these injuries, the small intestine is the most commonly affected site (55.8%), followed by the large intestine (38.6%) and the stomach (3.9%) [20]. A study involving 12,354 patients undergoing laparoscopic surgery reported 15 cases of rectal injury [21]. In our study, one patient who had undergone two previous surgeries required transvaginal repair of a rectovaginal fistula, resulting in a yellow-green vaginal discharge. Two additional patients experienced colonic injuries during total hysterectomy. Common strategies for managing rectal injuries include laparotomic or laparoscopic colostomy, one-stage repair, low anterior resection, and partial rectal resection [4, 22, 23, 24]. To minimize the risk of injury during laparoscopic surgery, it is crucial to ensure that the separation of the intestine is performed as close to the uterus as possible.

Three cases of vascular injury were observed in this study. Blood vessels can sustain damage during the separation of adhesions or trocar insertion [25]. Only five patients (0.03%) necessitated conversion to laparotomy in this study. Two cases were due to the intraoperative discovery of an ovarian malignant tumor, one case was due to extensive hemorrhage from a cesarean scar pregnancy, and two cases were attributed to a large uterus and extensive pelvic adhesions. The rate of conversion to laparotomy in this series was significantly lower than the previously reported value of 5% for patients undergoing hysterectomy for benign gynecologic disease [15]. The lower rate observed in this study may be attributed to the majority of operations being technically straightforward procedures such as adnexal surgery or myomectomy.

This study encompassed a substantial number of patients who received consistent treatment and management within the same hospital. However, it is important to acknowledge several limitations of this study. Firstly, being a retrospective study, there is a possibility of selection bias or information bias affecting the findings. Secondly, the generalizability of the results is uncertain due to the study being conducted at a single center. Lastly, there may be additional parameters not considered in the analysis that could have acted as confounding factors influencing the results.

The findings suggest that meticulous separation of adhesions and regular examination of the bladder, ureter, bowel, blood vessels, and other vital organs may effectively mitigate the risk of complications. These results contribute valuable data on the risk factors associated with major complications in gynecologic laparoscopic surgery among Chinese patients. Furthermore, these findings could aid in the appropriate selection of patients for preventive measures.