A case control study of vNOTES hysterectomy with the da Vinci surgical system and conventional vNOTES hysterectomy

Abstract

The aim of the case control study was to compare surgical outcomes of transvaginal natural orifice transluminal endoscopic surgery (vNOTES) hysterectomy with the da Vinci surgical system (dVSS) and conventional vNOTES. A case control study was performed on 25 cases in our hospital. Patients (n = 8) who underwent vNOTES hysterectomy with dVSS were selected to compare with the control group (n = 17) consisted of patients who underwent conventional vNOTES. Patients in the 2 groups underwent different operations respectively, and no case was transferred to transabdominal laparoscopy. In the conventional vNOTES group, 1 patient happened intraoperative hemorrhage of about 1000 mL, and was treated with blood transfusion, and the other one of vNOTES hysterectomy with dVSS had poor incision healing within 1 month after surgery. The other patients had no intraoperative and postoperative complications. The difference of pain scores on the first day (P = .006) and the third day (P = .045) after the 2 surgical methods differed significantly. No statistical differences were observed in operation time, median hospital stay, blood loss, decreased hemoglobin 3 days after surgery, and postoperative white blood cell count. vNOTES hysterectomy with dVSS is safe and feasible, and can achieve the same effect as the conventional vNOTES hysterectomy. And this method may alleviate the pain of patients.

1. Introduction

Since the da Vinci surgical system (dVSS) was approved by the FDA in 2005, more and more surgeons have been using the system to perform a wide variety of surgical procedures. These surgeries for gynecology are also progressing and developing. Currently, hysterectomy assisted by the dVSS is used in the United States for both benign and malignant diseases increasingly, and it has become the second most common surgery after cesarean in the United States.^[1] At present, there are many options for hysterectomy, such as open surgery, laparoscopic surgery, vaginal surgery and even surgery assisted by the dVSS. But if there is enough advanced equipments and the surgeon’s skills, minimally invasive surgery (MIS) is still recommended for rapid postoperative rehabilitation. The American Society of Gynecologic Laparoscopists recommends that laparoscopic surgery for hysterectomy is preferred for benign diseases because of less perioperative morbidity.^[2–4]

Natural orifice transluminal endoscopic surgery is a significant innovation in MIS.^[5] Transvaginal natural orifice transluminal endoscopic surgery (vNOTES) has been used and developed in various gynecological surgeries in recent years. In 2012, Ahn et al^[6] proved the feasibility and safety of vNOTES in gynecological surgery firstly, and it has great significance in the development of vNOTES. Now most surgeons with experience in single-port laparoscopic have the ability to procedure surgery by vNOTES, such as oophorectomy, salpingectomy, adnexectomy, myomectomy, and hysterectomy. Otherwise, some doctors are even able to complete complex operations such as lymphadenectomy, tumor staging surgery, and sacrak colpopexy.^[7]

vNOTES has obvious advantages over traditional transabdominal laparoscopy in terms of reducing pain and improving patient satisfaction. However, single-port laparoscopy has higher requirements for doctors’ operation experience.^[8] dVSS provides a high-resolution 3D view and wrist motion of mechanical arm, which provides more precision and flexibility.^[9] And it can solve the drawbacks of single-port laparoscopy perfectly and effectively. It has many advantages, such as precision, flexibility, microinvasive, and filtering of hand tremor, so that can facilitate surgical operation, reduce the operation difficulty, and shorten the operation time.^[10] Therefore, we combined vNOTES and dVSS to explore a new surgical method.

2. Methods

2.1. General information

A retrospective study was conducted in our hospital from May 2019 to the present. This study was approved by the Chengdu Women’s and Children’s Central Hospital Ethics Committee. We collected cases which underwent traditional vNOTES hysterectomy or vNOTES hysterectomy assisted by dVSS due to benign lesions such as hysteromyoma, adenomyosis, uterine prolapse, endometrial lesions, and cervical intraepithelial neoplasia (conical resection completed, negative resection margin, patients who were older than 40 years and had no fertility requirement). The exclusion criteria were as follows: complete closure of rectovaginal pouch, severe endometriosis, and suspected gynecological malignancy. Uterine size was greater than gestation as 12 weeks (mean 280 g), history of cesarean and pelvic surgery, and no delivery were not considered contraindications. All patients signed surgical consent before surgery and were informed of possible risks during surgery. If necessary, they may be transferred to transumbilical laparoscopic or even open surgery.

Since 2018, vNOTES hysterectomy had been performed in our hospital, and complex operations such as tumor staging and lymphadenectomy had been gradually carried out. Since the introduction of the dVSS in May 2021, we had gradually tried to perform vNOTES hysterectomy assisted by the dVSS. This study was a case control study of 8 robot-assisted vNOTES hysterectomy and 17 traditional vNOTES hysterectomy both performed by Dr YH Lin in our hospital. The data collection of age, body mass index, pregnancy and delivery history, pelvic surgery history, uterine size, operation time, intraoperative blood loss, postoperative hemoglobin decline, white blood cell count, pain score, postoperative complications, and other indicators of patients in the 2 groups were recorded and compared.

All operations were performed by one doctor, eliminated data interference caused by different doctor. The doctor has rich experience in laparoscopic hysterectomy and had completed hundreds of vNOTES surgeries independently, including adnexectomy, hysterectomy, and lymphadenectomy for malignant tumors. His personal surgical techniques are stable relatively. And he has obtained the training certificate of dVSS and completed the corresponding surgical training. He had performed more than 10 laparoscopic surgeries assisted by dVSS before vNOTES hysterectomy assisted by dVSS.

2.2. Preoperative preparation

Patients in both groups were given 90 mL sodium phosphate 1 day before surgery. Vagina was rinsed twice with diluted iodophor solution. Intravenous drops of cefazolin sodium/cefmetazole sodium/clindamycin were performed 30 minutes before surgery until 48 hours after surgery to prevent infection.

2.3. Surgical method

The urethral tube was indwelled after routine disinfection by bladder lithotomy position. After the vaginal cervix was disinfected again, the anterior and posterior walls were pulled by the vaginal hook, and the cervix was pulled by the cervical forceps to expose the anterior fornix of the vagina fully. The vaginal wall was cut about 0.5 cm above the bladder groove. Then the bladder was pushed and the anterior fornix opened. The posterior fornix of the vagina is then opened. And bilateral sacro-uterine ligaments were solidified with bipolar forceps and cut. A PORT was inserted, and CO₂ was filled.

2.3.1. vNOTES hysterectomy assisted by dVSS.

Fixed robot arm, endoscope, and cannula were arranged in the shape of “品.” And bilateral uterine arteries, uterine round ligaments, ovarian proper ligaments, and mesosalpinxs/ovarian suspensory ligaments were cut by bipolar and unipolar electrocoagulation. After the uterus was isolated, the surgeon inspected all ends to ensure complete hemostasis. The assistant inserted the endoscopic instrument to assist in pumping, flushing, specimen removal, and other operations. At the end of surgery, the vagina was sutured continuously with an absorbable thread under direct vision.

2.3.2. Traditional vNOTES hysterectomy.

The upper cannula was inserted with the endoscope, and the left and right sides were inserted with forceps. The bilateral uterine arteries, uterine round ligaments, ovarian proper ligaments, mesosalpinx/ovarian suspensory ligaments were cut with ultrasonic scalpel. After the uterus was isolated, the surgeon inspected all ends to ensure complete hemostasis. The assistant inserted the endoscopic instrument through the bottom cannula to assist in pumping, flushing, specimen removal and other operations. At the end of surgery, sutured the vagina continuous with an absorbable thread under direct vision.

2.4. Statistical analysis

SPSS 23.0 software (IBM, Armonk, NY) was used for statistical analysis. t test or nonparametric Wilcoxon rank sum test was used for measurement data, and χ² test or nonparametric Wilcoxon rank sum test was used for counting data. P < .05 was considered significant statistically.

3. Results

The mean age of all patients was 50.6 years old, with the youngest 36 and the oldest 74 years old, and postmenopausal patients account for about 25%. In the traditional vNOTES group, 25% of patients had previous surgery. In the vNOTES group assisted by the dVSS, 41% of patients had previous surgery. The traditional vNOTES group had an average uterine weight of 140 g, the heaviest was about 500 g, and the lightest was 30 g. VNOTES group assisted by the dVSS had an average uterine weight of 60 g, the heaviest was about 350 g, and the lightest was 40 g. There were no statistically significant differences in age, body mass index, history of pelvic surgery, proportion of pregnancy, childbirth, menopause, additional surgery, diagnosis, and uterine size between the 2 groups (P < .05), as shown in Table 1.

Table 1.

General data of hysterectomy assisted by da Vinci surgical system versus traditional vNOTES.

Variates	vNOTES	Robots	t/z/X2	P value*
Age (yr)	50.71 ± 9.55	50.50 ± 5.4	0.056	.955†
Weight (kg)	59.5 ± 9.78	55.69 ± 6.3	1.003	.326†
BMI (kg/m2)			−0.564	.604‡
≤20	2 (11.8%)	1 (12.5%)
20–24.9	11 (64.6%)	6 (75.0%)
25–29.9	2 (11.8%)	1 (12.5%)
≥30	2 (11.8%)	0 (0.00%)
History of pelvic and abdominal surgery			1.172	.903§
No operations	10 (58.8%)	6 (75.0%)
Myomectomy	2 (11.8%)	0 (0.00%)
Cesarean section	2 (11.8%)	1 (12.5%)
Other operations	3 (17.6%)	1 (12.5%)
Gravidity	3 (1.5–4)	2.5 (2–3.75)	−0.269	.788‡
Parity	1 (1–1.5)	1 (1–1.75)	−0.297	.766‡
Menopause			–	1.000§
No	13 (76.5%)	6 (75%)
Yes	4 (23.5%)	2 (25%)
Additional surgery			–	1.000§
Salpingectomy	13 (76.5%)	6 (75%)
Adnexectomy	4 (23.5%)	2 (25%)
Diagnosis			–	.128§
Myoma of uterus	10 (58.8%)	2 (25%)
Endometrial lesions	2 (11.8%)	1 (12.5%)
Cervical lesions	1 (5.9%)	4 (50%)
Metroptosis	3 (17.6%)	1 (12.5%)
Hydatidiform moles	1 (5.9%)	0 (0.00%)
Weight of the uterus (g)	140 (50–225)	60 (42.5–197.5)	−0.758	.448‡

BMI = body mass index, vNOTES = transvaginal natural orifice transluminal endoscopic surgery.

^*Continuous values conforming to normal distribution were represented by mean ± SD, and nonconforming to normal distribution were represented by median; categorical variables were represented by numbers (%)

^†t test.

^‡Rank sum test.

^§Chi-square test.

Patients in the 2 groups underwent different operations respectively, and no patient was transferred to laparoscopy. One patient in the traditional vNOTES group, suffered accidental vascular injury and hemorrhage of about 1000 mL due to parauterine adhesions and received blood transfusion after surgery. Perioperative examination results of all patients were normal, and no patients developed postoperative fever (body temperature ≥38°C). There were no significant differences in operative time, postoperative mean hospital stay, estimated intraoperative blood loss, decreased hemoglobin 3 days after surgery, and postoperative white blood cell count between the 2 surgical methods. In vNOTES hysterectomy assisted by dVSS, 1 patient developed poor incision healing in 1 month after surgery, accompanied by yellow purulent secretions, but no fever, abnormal blood pattern, whose incision healed well after outpatient treatment. Other patients had no postoperative complications. There was no statistical difference in the pain scores on the day of surgery and the second day after surgery, but the difference was statistically significant on the first and third day after surgery, as shown in Table 2.

Table 2.

Comparison of surgical results between da Vinci surgical system and traditional vNOTES hysterectomy.

Variates	VNOTES	Robots	t/z/X2	P value*
Operating time (min)	114.24 ± 36.29	125.88 ± 44.74	−0.695	.494†
Damage of tissues and organs	0	0	–	–
Hemorrhage	1	0	–	1.000§
Estimating blood loss intraoperative (mL)	100 (50–100)	50 (20–87.5)	−1.764	.078‡
Hemoglobin drop (g)	20 (10.5–26)	9.5 (3.75–18.25)	−1.636	.102‡
Postoperative white blood cell count (×109/L)	8.57 ± 2.37	8.79 ± 2.37	−0.219	.828†
Maximum temperature in 72 hours after surgery	36.98 ± 0.56	36.83 ± 0.17	0.769	.450†
Mean postoperative hospital stay	4 (4–5)	4 (3.25–4)	−1.401	.161‡
Postoperative pain score	3 (3–3)	3 (2.25–3)	−0.825	.570‡
The first day	3 (2–3)	2 (2–2)	−2.792	.006‡
The second day	2 (1–2)	1 (1–1.75)	−1.816	.097‡
The third day	1 (1–1)	1 (0–1)	−2.142	.045‡
Postoperative poor wound healing	0	1	–	–
Postoperative infection	0	0	–	–
Postoperative bleeding	0	0	–	–

BMI = body mass index, vNOTES = transvaginal natural orifice transluminal endoscopic surgery.

^*Continuous values conforming to normal distribution were represented by mean ± SD; nonconforming to normal distribution were represented by median; categorical variables were represented by numbers (%).

^†t test.

^‡Rank sum test.

^§Chi-square test.

4. Discussion

Total hysterectomy has a history for hundreds of years from vaginal surgery up to now. However, poor visualization and limited operation space are the important limiting factors. Vaginal hysterectomy will be intensely difficult if there is a complication such as low pubic arch, narrow vagina, fixed uterus, accidental pelvic adhesion, and uterine volume enlargement.^[11] After a long period of development, it develops from laparotomy to laparoscopy, and then single-port laparoscopy, and back to the vNOTES. Gynecologists progress the surgery more minimally invasive and the wound more beautiful. According to previous reports, vNOTES hysterectomy was not inferior to laparoscopic hysterectomy regarding surgical outcomes, with a shorter operative time, shorter recovery time, less postoperative pain, and fewer postoperative complications also. Especially for female patients it is more beautiful because of no-scar.^[12,13] Therefore, vNOTES is attractive to both doctors and patients.

Hysterectomy without prolapse can be performed by vaginal surgery if the uterus is normal volume. Studies have shown that more than 60% of hysterectomy is feasible for vaginal resection, including women without delivery.^[14,15] However, most patients undergoing hysterectomy are postmenopausal women, so preventive salpingectomy and adnexectomy is routinely required to reduce the occurrence of fallopian and ovarian tumors. For patients with tight vagina, normal pelvic floor muscle function, the exposure of the fallopian tubes and ovaries is difficult especially. For patients who need an ovariectomy, it is very difficult to reach the ovary through vagina. Even if we can reach, we might cause ovarian ligament rupture and hemorrhage due to pull violently. And poor vision is due to hemostasis is indeterminacy. The combination of vaginal hysterectomy and vNOTES can effectively extend our surgical field and operating space, so we can cut broad ligament and round ligament under a clearer vision (Figure S1, Supplemental Digital Content, http://links.lww.com/MD/L865 and Figure S2, Supplemental Digital Content, http://links.lww.com/MD/L866). Similarly, we can exposure the adnexa clearly; even with some adhesions, we can perform adnexectomy than vaginal surgery. The surgical site of the pelvis can also be examined clearly, and thorough hemostasis can reduce the risk of bleeding and postoperative complications significantly (Figure S3, Supplemental Digital Content, http://links.lww.com/MD/L867). In addition, for patients with a history of multiple abdominal surgeries, especially for patients with transumbilical laparoscopy, transvaginal operation can avoid the injury of the upper abdomen (Figure S4, Supplemental Digital Content, http://links.lww.com/MD/L868 and Figure S5, Supplemental Digital Content, http://links.lww.com/MD/L869).

In 2012, Su et al reported 16 patients with benign uterine diseases who underwent vNOTES hysterectomy firstly and were followed up for 2 and 6 months after operation. The incision healed well, without dyspareunia, post-intercourse bleeding, and other symptoms.^[16] In our study, about 36% of the 25 patients had previous pelvic surgery history, but all patients completed surgery according to the established surgical plan, and only 1 patient had poor incision healing of vagina, while the rest of the patients had no postoperative complications and had ideal postoperative recovery. Conclusion is that vNOTES hysterectomy is safe, reliable, and effective in most patients, whether assisted by dVSS or traditional instruments. The pain scores of patients assisted by the dVSS on the first and third day after surgery were significantly lower than the traditional vNOTES group. However, it is still impossible to rule out whether there is a certain psychological implication due to the fact that the patients saw the dVSS before surgery and knew that they had received the most advanced MIS. Later, we will conduct a randomized double-blind experiment for further verification.

vNOTES have obvious advantages in reducing pain and improve patients satisfaction than traditional abdominal laparoscopic surgery, but single-port laparoscopic operation is difficult to doctors because of linear vision, chopsticks effect, and instruments interfere.^[8] dVSS can solve the disadvantages of single-port laparoscopic operation perfectly and effectively.^[9] In vNOTES hysterectomy, the operation space is narrow and the field of vision is limited. Especially for the treatment of uterine blood vessels, the dVSS has its unique advantages to perform elaborate operation compared with the traditional instruments which cannot turn or operate in a straight line.

In addition, the dVSS can also realize the possibility of remote surgery, which is simpler and easier to learn for young doctors than traditional laparoscopy.^[17] The dVSS has several specific surgical benefits: 3-dimensional vision, quicker learning curve, high definition, greater precision, and greater ergonomic potential^[18]; vNOTES hysterectomy assisted by dVSS is also more friendly for young surgeons. Studies have shown that for surgeons with experience in single-port laparoscopy and abdominal robotic surgery, they need to complete 10 cases of vNOTES hysterectomy assisted by dVSS, and 10 to 20 cases of port placement and robot docking can achieve proficiency.^[19] Therefore, the application of dVSS into vNOTES hysterectomy is a new requirement for MIS. Our experiment also shows that vNOTES hysterectomy assisted by dVSS is safe and effective, and it can be popularized widely. However, dVSS has many limitations such as the surgeons must undergo professional training, and the huge robot arm may cause collisions and interference. The major limitations of robotic surgery are its costs and unavailability in all centers.^[18] The smoke problem of dVSS is also a difficult problem for surgeons. Currently, we are adding an assistant to use traditional laparoscopic instruments to assist, and we are also exploring vNOTES surgery without pneumoperitoneum, which can also effectively solve the problem.

We are exploring the operation gradually, and wish to establish a set of standardized operation procedures, so that the docking and placement of instruments are more simple and accurate. It also can shorten the learning curve. At present, we find that placing the endoscope and the 2 robot arms in “品” shape can solve the problem of collisions (Figs. 1 and 2). Some studies have also found that the dVSS has a long surgical preparation time and high surgical costs.^[20] For hysterectomy by experienced laparoscopists, dVSS does not improve surgical outcomes. And in patients with normal weight, it even cost more time and expense.^[21] But in our study, there was no significant difference in operation time between 2 groups. Wright et al^[22] studied the randomized controlled trial of hysterectomy with dVSS for benign gynecological diseases and concluded that the cost of robotic surgery was 25% higher than traditional instruments. Therefore, the dVSS cannot be popularized widely due to high-cost, and its value in health economics needs to be further evaluated. It also becomes a factor needing to consider when choosing surgical methods.

Figure 1.

View of robot arm placement.

Figure 2.

View of “品” font placement of the robot arm.

At present, vNOTES surgery is more and more used in various medical fields, and more and more clinical controlled studies have been gradually carried out. Robotic surgery is the inevitable trend of medical development in the future; more and more operations will be completed by dVSS. In our study, there was no difference in postoperative pain score, bleeding, fever, infection, and other risks between the 2 groups, which confirmed that vNOTES hysterectomy assisted by dVSS was feasible and safe, and could achieve the same effect as traditional vNOTES. If the economic cost decreases with the popularity of the dVSS in the future, the dVSS will be a better choice, considering the flexibility and precision. In the future, we will conduct a large randomized double-blind controlled trial to further explore the advantages and disadvantages of this surgical method.

Author contributions

Data curation: Chengling Zhang, Dandan Liu, Qiang Zhang, Qiaoqiao Li, Li He, Huisheng Ge.

Investigation: Chengling Zhang, Yonghong Lin, Huisheng Ge.

Writing – original draft: Chengling Zhang.

Writing – review & editing: Huisheng Ge.