Clinical efficacy and safety study of vNOTES for benign ovarian tumors in obese patients

Abstract

To evaluate the clinical efficacy and safety of transvaginal natural orifice transluminal endoscopic surgery (vNOTES) for treating benign ovarian tumors in obese patients. A retrospective analysis was conducted on the clinical data of 35 obese patients who underwent vNOTES for benign ovarian tumor resection and 41 obese patients who underwent multi-port laparoscopic surgery (MPLS) during the same period from January 2021 to June 2024 at Qinghai Red Cross Hospital. Key parameters such as operative time, intraoperative blood loss, intraoperative and postoperative complications, hospitalization duration, postoperative anal exhaust time, postoperative visual analog scale (VAS) score, and SF-36 score were analyzed. No statistical differences were observed between the two groups regarding baseline characteristics such as age, body mass index (BMI), tumor diameter, parity, and history of pelvic surgery. The vNOTES group exhibited shorter operative times compared to the MPLS group, with no significant differences in tumor pathology, intraoperative blood loss, or tumor rupture rates. Postoperatively, the vNOTES group had shorter hospital stays, fewer postoperative complications, lower 24-hour postoperative VAS scores, and higher three-month postoperative SF-36 scores compared to the MPLS group. No differences were found between the groups concerning anal exhaust time, sexual satisfaction rate, or 24-hour postoperative VAS scores. vNOTES is a safe and feasible surgical method for treating benign ovarian tumors in obese patients, offering advantages such as no abdominal incisions and quicker postoperative recovery.

Introduction

With the rapid development of minimally invasive surgery in recent years, the postoperative quality of life and rapid recovery of patients have become significant concerns for surgeons, besides ensuring surgical success¹. In gynecology, vNOTES combines laparoscopy with traditional vaginal surgery, offering advantages such as accelerated postoperative recovery and the absence of abdominal incisions for improved aesthetic outcomes². In developed countries, over 20% of adult women suffer from obesity^3–5. When these patients require surgical intervention for gynecological conditions, the increased thickness of the abdominal wall in obese individuals can complicate traditional open or laparoscopic surgeries, raising the risk of surgical difficulties and complications. Therefore, vNOTES may offer advantages for obese patients. The clinical efficacy and safety of vNOTES for treating benign ovarian tumors in obese patients remain unclear. This study aims to evaluate the feasibility and safety of vNOTES by comparing it with MPLS in the treatment of benign ovarian tumors in obese patients, assessing preoperative, intraoperative, and postoperative outcomes to provide guidance for choosing surgical approaches for this patient population.

Materials and methods

General data

A retrospective analysis was conducted on 35 obese patients who underwent vNOTES for benign ovarian tumor resection at Qinghai Red Cross Hospital from January 2021 to June 2024, and 41 obese patients who received multi-port laparoscopic ovarian tumor resection during the same period. Clinical data were collected and compared to assess the outcomes of both surgical techniques. This retrospective study was conducted at Qinghai Red Cross Hospital and it adhered to the principles outlined in the Declaration of Helsinki. The study was approved by the ethics committee of Qinghai Red Cross Hospital (LW-2024-136). Individual consent was obtained from all patients in this retrospective analysis.

The inclusion criteria were: (1)BMI ≥ 30 kg/m2. (2)Being between 18 and 50 years old. (3)Having a preoperative risk of malignancy index (RMI) indicating a high likelihood of a benign condition. (4)Having regular postoperative follow-up. (5)Providing informed consent by agreeing to participate in the study and signing a consent form. The exclusion criteria were: (1)Patients identifying as asexual. (2)Patients with vaginal stenosis. (3)Patients with vaginal infections. (4)Patients with a history of pelvic surgery. (5)Patients with ovarian cysts larger than 10 cm. (6)Suspected cases of pelvic adhesion. (7)Suspected cases of malignancy. (8)Pregnant Patients.

Surgical techniques

All patients underwent rapid pathologic diagnosis during surgery and all pathological diagnoses were benign. whether or not to place a drain postoperatively was based on selective intraoperative placement, such as the need to place a drain for large surgical wounds and heavy bleeding. In addition, all patients followed the discharge criteria: resumption of a semi-liquid diet; cessation of intravenous rehydration; good pain relief with oral analgesic medication; good wound healing with no signs of infection; and good organ functional status on review and free movement.

MPLS

Under general anesthesia, we selected puncture points at the umbilical region, McBurney’s point, the reverse McBurney’s point, and the midpoint between the reverse McBurney’s point and the umbilicus. Trocar lapascopy and operative instruments were inserted at these sites. Through careful laparoscopic examination of the pelvic cavity, we identified the affected ovary and observed the cyst’s location, diameter, and mobility. The ovarian cortex of the affected ovary was dissected, and the cyst was separated from the normal ovarian tissue, taking care to avoid cyst rupture. The cyst wall was gradually peeled away and placed in a specimen retrieval bag for extraction. The ovarian incision was sutured with absorbable stitches, followed by rapid pathological examination. The pelvic and abdominal cavities were irrigated with saline, a drainage tube was placed, and the puncture sites were sutured.

vNOTES

The surgery was performed by two experienced obstetricians and gynecologists with specialized training in vNOTES and one assistant surgeon from Qinghai Red Cross Hospital. Under general anesthesia, the cervix and posterior vaginal fornix were exposed, and a vasopressin solution (0.12 U/mL) was injected at the junction of the cervical and posterior vaginal wall mucosa to separate the vaginal rectal space. A 2 cm arcuate incision was made at the top of the posterior fornix, the rectum was bluntly separated, and the peritoneum at the rectouterine pouch was opened to access the pelvic cavity. A port was installed, and pneumo-peritoneum was established with an intraoperative pressure maintained at 8–10 mmHg. The remainder of the procedure followed MPLS protocols. The resected specimen was removed transvaginally, and the peritoneum and vaginal wall were sutured with absorbable stitches. An iodine-soaked gauze was placed inside the vagina and removed after 24 h. (see Fig. 1).

Fig. 1.

Process of vNOTES preoperative loading of port (A) Incision of the posterior vaginal vault. (B) Placement of port in the posterior fornix. (C) Laparoscopic instrument holes for port.

Observation indicators

We compared preoperative general conditions (age, body mass index (BMI), tumor diameter, number of deliveries, history of pelvic surgery) and intraoperative conditions (surgical time, tumor pathology, intraoperative blood loss, number of tumor ruptures) between the two groups. Postoperative conditions such as hospital stay duration, incidence of postoperative complications, VAS score at 24 h post-operation, SF-36 score at 3 months post-operation, first flatus time, and sexual satisfaction rate were also assessed.

Statistical analysis

Statistical analysis was performed using IBM SPSS Statistics (Version 26.0, URL link: https://www.ibm.com/spss). Continuous variables were tested for normality, expressed as mean ± standard deviation if normally distributed, and compared using the t-test. Categorical variables were expressed as n (%) and compared using the χ2 test. A P-value < 0.05 was considered statistically significant.

Results

Preoperative general indicators comparison

No statistical differences were observed between the vNOTES and MPLS groups in terms of age, BMI, tumor diameter, number of deliveries, or history of pelvic surgery (P > 0.05) (see Table 1).

Table 1.

Comparison of preoperative general information.

Group	MPLS (n = 41)	vNOTES (n = 35)	P value
Age (years)	31.7 ± 7.2	32.1 ± 6.5	0.463
BMI (kg/m2)	32.4 ± 2.9	31.8 ± 2.3	0.502
Diameter of tumor (mm)	5.3 ± 1.2	5.1 ± 2.2	0.674
Number of deliveries, n (%)
< 2	22 (53.7)	18 (51.4)	0.214
≥ 2	19 (46.3)	17 (48.6)
History of previous pelvic surgery, n (%)	12 (29.3)	10 (28.6)	0.171

Intraoperative conditions comparison

All surgeries were successfully completed without injury to adjacent organs and all pathological diagnoses were benign. The vNOTES group had significantly shorter operative times compared to the MPLS group (P < 0.05). No significant differences were observed in tumor pathology, intraoperative blood loss, or number of tumor ruptures between the two groups (P > 0.05) (see Table 2).

Table 2.

Comparison of intraoperative conditions.

Group	MPLS (n = 41)	vNOTES (n = 35)	P value
Pathological type, n (%)
Teratoma	6 (14.6)	4 (11.4)	0.062
Serous cystadenoma	18 (43.9)	15 (42.9)
Endometriotic cyst	13 (31.7)	10 (28.6)
Others	4 (9.8)	6 (17.1)
Surgical time (minutes)	77.5 ± 23.1	63 ± 28.9	0.043
Blood loss (mL)	45.3 ± 11.5	47.4 ± 13.6	0.645
Tumor rupture, n (%)	7 (17.1)	5 (14.3)	0.087

Postoperative conditions comparison

The vNOTES group experienced shorter hospital stays, fewer postoperative complications, lower VAS scores at 48 h post-operation, and higher SF-36 scores at 3 months post-operation compared to the MPLS group (P < 0.05). However, there were no significant differences between the groups in terms of time to first flatus, sexual satisfaction rate, and VAS scores at 24 h post-operation (P > 0.05). Patients in the MPLS group had surgical incision infections on postoperative days 4 and 5, subcutaneous emphysema on postoperative day 1, and lower-extremity venous thrombosis on postoperative day 5, and patients in the vNOTES group had surgical incision infections on postoperative day 4 (see Table 3).

Table 3.

Comparison of post-surgical conditions.

Group	MPLS (n = 41)	vNOTES (n = 35)	P value
Length of hospitalization (days)	7.4 ± 1.2	5.1 ± 1.4	0.032
Postoperative complication, n (%)
Surgical incision infections	4 (9.8)	1 (2.9)	0.005
Subcutaneous emphysema	2 (4.9)	0
Lower extremity venous thrombosis	1 (2.4)	0
Duration of anal defecation (hours)	17.4 ± 4.2	20.1 ± 3.5	0.098
Sexual satisfaction, n (%)	33 (80.5)	28 (80.0)	0.741
VAS score at 12 h postoperatively	3.3 ± 1.1	3.0 ± 0.6	0.472
VAS score at 24 h postoperatively	2.5 ± 1.3	1.7 ± 0.9	0.021
SF−36 score at 3 months postoperatively	104 ± 9.3	127.3 ± 8.8	0.039

Discussion

With the rapid advancement of gynecological minimally invasive techniques, there is an increasing focus on treatment efficacy, safety, postoperative recovery speed, quality of life, and cosmetic outcomes^6,7. The unique natural cavity of the vagina has facilitated the rapid development of vNOTES in gynecologic surgery⁸. vNOTES combines the strengths of single-port laparoscopy and traditional vaginal surgery, offering superior clinical outcomes. Therefore, it is especially important to train a gynecologist with vNOTES. Results of a study on the learning curve of vNOTES showed that for a team skilled in minimally invasive surgery, 5 cases are required to rich competence and 25 to rich proficiency in vNOTES hysterectomy, confirming that vNOTES hysterectomy is a feasible and reproducible approach for benign indications with a short learning curve and low rate of perioperative complications⁹.

The results indicate that vNOTES significantly reduces operative time in obese patients. Traditional laparoscopic surgery is more challenging in obese patients, particularly during puncture and insufflation^10,11. In contrast, vNOTES eliminates the need for abdominal wall incisions, thus simplifying these steps and reducing operative time¹². Shorter operative time not only decreases anesthesia duration but may also lower the risk of intraoperative complications¹³. Obese patients often have additional health issues such as hypertension and diabetes, which increase anesthesia risks¹⁴. vNOTES reduces both anesthesia time and medication usage, thereby mitigating anesthesia-related risks¹⁵. A randomized controlled trial involving 114 patients showed that the operative time for the vNOTES group (48.33 ± 33.12 min) was significantly shorter compared to the MLPS group (72.23 ± 43.63 min), with fewer intraoperative complications, suggesting that vNOTES is a promising method for ovarian cystectomy¹⁶.

The study further found that postoperative complications and hospital stay were significantly lower in the vNOTES group compared to the MLPS group, although intraoperative blood loss did not differ statistically between the two groups. Due to the thicker abdominal wall in obese patients, traditional laparoscopic surgery requires multiple abdominal wall incisions, increasing the risk of postoperative wound infection, hernias, and poor wound healing^17–19. By accessing the abdominal cavity via the vagina, vNOTES avoids abdominal wall incisions, significantly reducing related complications and accelerating postoperative recovery, which is particularly crucial for obese patients^20–22. Research has shown that vNOTES leads to a notable reduction in hospital stay and faster postoperative recovery, benefiting both patient rehabilitation and healthcare resource utilization. Additionally, vNOTES has been associated with fewer postoperative wound infections and hernias, providing robust evidence for its safety²². However, it is important to note that while vNOTES demonstrates a lower complication rate in this study, it does not eliminate all risks²³. The use of natural orifices for abdominal access may increase the risk of intraoperative infection, particularly if procedures are not performed correctly or preoperative disinfection is inadequate²⁴. Future research should focus on further reducing potential risks associated with vNOTES to ensure its safety in clinical practice.

The study also found that vNOTES resulted in significantly lower VAS scores at 48 h postoperative and higher SF-36 scores at 3 months postoperative. The absence of abdominal wall incisions in vNOTES contributes to significantly reduced postoperative pain²⁵. Obese patients are particularly sensitive to postoperative pain, and effective pain management is crucial for recovery²⁶. Reduced postoperative pain facilitates early mobilization and rapid recovery, allowing patients to return to normal life and social activities sooner, thereby improving postoperative quality of life²⁷. Studies have shown that vNOTES results in significantly lower VAS scores compared to MLPS, indicating that the smaller surgical wounds and faster recovery associated with vNOTES reduce postoperative pain and offer advantages in enhancing long-term quality of life²⁸. Although no significant differences were observed in sexual satisfaction between the two groups, and long-term pregnancy and delivery outcomes were not statistically significant due to the short study duration and small sample size, further extensive clinical research is needed to determine these aspects.

In conclusion, the results of this study suggest that vNOTES offers significant advantages in the treatment of benign ovarian tumors in obese patients, including shorter operative and hospital stay times, fewer postoperative complications and pain, and improved quality of life. vNOTES is a safe and effective surgical approach for treating benign ovarian tumors in obese patients. However, given the complexity of the procedure and potential risks, further large-scale, prospective studies are needed to validate its safety and efficacy in diverse patient populations.

Author contributions

WF: Writing – Original Draft, Data Management. LYQ: Data Management, Writing - Review and Editing. XY: Data Management, Writing – Review & Edit. WDD: Data Management, Writing – Review & Edit. LLL: Investigating, Writing - Censoring and Editing. SYJ: Formal Analysis, Writing – Review and Editing. BX: Formal Analysis, Writing – Review and Editing. MCH: Investigation, Methodology, Project administration, Software, Supervision, Visualization, Writing – original draft, Writing – review & editing. WLH: Conceptualization, Formal analysis, Investigation, Methodology, Validation, Writing – original draft, Writing – review & editing. BYF: Conceptualization, Investigation, Methodology, Project administration, Visualization, Writing – original draft, Writing – review & editing.

Funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by Qinghai Province obstetrics and gynecology disease clinical medical research center(2024-SF-L03).

Data availability

The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Competing interests

The authors declare no competing interests.

Ethics statement

The studies involving humans were approved by Qinghai Red Cross Hospital (KY-2024-89). The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.