Safety and feasibility of laparoendoscopic single-site surgery in the management of giant ovarian cysts

Objective To investigate the safety and feasibility of laparoendoscopic single-site surgery (LESS) in the treatment of giant ovarian cysts. A total of 76 patients with giant ovarian cyst (diameter ≥ 10 cm) who in our from 2018 to 2021 were divided into experimental cohort (single-port laparoscopic cohort) (n = 30) and control cohort (traditional laparoscopic cohort) (n = 46).The operation time, intraoperative blood loss, intraoperative cyst uid spillage rate, application of postoperative analgesic drugs, postoperative rst anus exhaust time, incidence rate of perioperative complications, length of postoperative hospital stay and other clinical indicators were summarized and analyzed between the two cohorts.


Conclusion
After adequate evaluation and screening of patients, the size of ovarian cysts cannot be the reason for refusing LESS surgery. It is safe and feasible for clinical promotion in the management of giant ovarian cysts.

Background
Ovarian cysts are a common disease in gynecological diagnostic and therapeutic activities, which can be successfully treated by laparoscopic surgery in most cases. However, for giant ovarian cysts (≥ 10 cm in diameter) several experts still recommend the laparotomy as their rst choice [1].Because the large ovarian cyst hampers adequate visualization of pelvic anatomy and limits the movement of laparoscopic equipment, a more important issue is the greater risk of intraoperative cyst rupture, which is likely to lead to dissemination of tumor [2,3].With the rapid development of microsurgical technique and the continuous improvement of patients' requirements for the aesthetics of scars, natural ori ce transluminal endoscopic surgery (NOTES) has emerged. Natural ori ce transluminal endoscopic surgery refers to a new endoscopic technique in which endoscopes and surgical instruments are placed through the natural ori ce of the human body (including the oral cavity, esophagus, stomach, colorectum, vagina, bladder, etc.) for various diagnostic and therapeutic procedures [4].Both laparoendoscopic single site surgery (LESS) and transvaginal natural ori ce transluminal endoscopic surgery (vNOTES) , which are commonly used in gynecology, are developed based on NOTES [5]. In recent years, obstetricians and gynecologists have also continuously explored the use of LESS technique in the treatment of giant ovarian cysts, and have achieved initial results [6][7][8].This article retrospectively analyzed the clinical data of 76 patients with giant ovarian cysts who underwent LESS (n=30) or traditional laparoscopic surgery (n=46) in our hospital, and analyzed its feasibility and safety, which are reported as follows. 2.2 Surgical process Experimental cohort : After general anesthesia, the patient was placed in the dorsal lithotomy position and had an indwelling catheter.A 2.5 cm longitudinal vertical incision was made in the umbilicus, the skin and subcutaneous tissue were incised, the peritoneum was opened into the abdominal cavity, and a single-port laparoscopic incision retractor was placed under direct vision. The device consists of three components: introducer, xed valve, and cannula. After the completion of the device, a CO 2 tube was connected to maintain the pneumoperitoneum pressure at 12 mmHg, and a laparoscopic lens was carefully placed for abdominal exploration. Ovarian cysts, ovaries, peritoneal surface, greater omentum, appendix, abdominopelvic adhesions, and ascites were explored as can as possible. During exploration, should pay attention to gentle movement to avoid puncturing the cyst. After ruling out the surgical contraindications, the removable port cover of the device was removed and extracorporeal ovarian cystectomy was operated. The inner edge of the wound retractor was covered with sterile gauze, the cyst surface was sutured with purse-string suture and then slowly lifted upwards, the tissue scissors were used to puncturing the central depression of the tissue, and the cyst uid was aspirated with vacuum suction system, during which also should to exploring whether the cyst was multilocular, and whether the cyst contained solid components. After cyst reduction, the cyst wall was stripped while pulling it out of the abdominal cavity (Picture A). Part of the dissected tissue was taken and sent for frozen pathology and the results were awaited during surgery. If the pathological results suggested that it was benign, ovarian repair was performed, the ovary was sutured into a long strip to facilitate passage through the small abdominal incision. After the ovary was delivered into the pelvis, the single-port laparoscopic port was reset and the abdominal cavity was carefully observed to determine any bleeding spots and other lesions with under laparoscopic lens. The pelvic and abdominal cavity was irrigated with a large amount of normal saline, and the abdominal wall incision was sutured (Picture B).If the patient required adnexectomy or other operations on the basis of preoperative conversation or intraoperative frozen section diagnosis, the completely collapsed ovarian cyst was returned to the abdominal cavity and other surgical procedure was performed.
Control cohort : Surgery was performed under general anesthesia, as in the LESS surgery all patients were in the dorsal lithotomy position and all had an indwelling catheter. A transverse incision of about 12 mm in length was made at the upper edge of the umbilicus or at the appropriate site of the upper abdomen which depended on the size of the cyst, with a trocar was placed in. Before connecting the CO 2 tube, the laparoscopic lens should be placed into this puncture tube to ensure that tube enters the abdominal cavity, thereby avoiding the formation of subcutaneous emphysema. After the formation of pneumoperitoneum, the abdominal cavity, omentum, and peritoneum were checked under Laparoscopic to exclusion surgical contraindications. After that two 5 mm trocars were placed in the avascular area of the left lower abdomen, and 5 mm and 12 mm trocars were placed in the right. Place the disposable surgical specimen extraction bag under laparoscopic monitoring, moved the ovarian cyst into the bag, pull the opening of the bag with atraumatic forceps to give a certain tension. A monopolar electric hook is used to make an incision on the surface of ovarian cyst. At the same time, the aspirator enters the cyst cavity through the incision to suck the cyst uid. Ovarian cysts were carefully dissected, in this process, whether the cyst cavity is multilocular and whether there is a solid component should also be checked.
The remaining ovarian tissue was sutured with absorbable sutures after complete dissection of the ovarian cyst. Tighten the bag, clamp it with atraumatic forceps, remove the 12 mm trocar in the right lower abdomen, and dragged the opening of the bag to the outside of the abdominal cavity through this puncture hole. Ensure that the opening of the collection bag has been completely pulled out of the abdominal cavity, relax the band and carefully take out the specimen with oval forceps. Pull the collection bag while removing the specimen. Finally, the collection bag is also taken out through the puncture hole. After that, check the integrity of the collection bag again. This process is completed under laparoscopic monitoring to observe whether the bag is damaged. It needed to reduce the CO2 pneumoperitoneum pressure to give a elasticity to the abdominal wall, which adds some di culties to laparoscopic monitoring. Specimens were sent for frozen pathology, if benign, the pelvis was irrigated with normal saline, and after determining the absence of active bleeding, the procedure was ended routinely. If the patient required adnexectomy or other operations on the basis of preoperative conversation or intraoperative frozen section diagnosis, after the cysts uid is absorbed, other surgical procedures were performed directly

Statistical data
Operation-related indicators were recorded, including operation time (min), intraoperative blood loss (ml), sac uid spillage rate, postoperative analgesic drug application, postoperative rst exhaust time (h), and postoperative hospital stay (d). Perioperative complications were recorded, including fever, poor incision healing, incisional hernia, intestinal obstruction, and pelvic in ammatory disease, ect.

Statistical Methods
SPSS 23.0 software was applied for statistical analysis. Categorical variable data are expressed as frequency (percentage).Continuous variable data are expressed as median (interquartile range [IQR]) or mean ± standard deviation ( X ± SD) after veri cation that the data are normally distributed. Basic information, surgical results, and postoperative pathology were compared between the two cohorts, using the t-test, Fisher's exact test, χ 2 test, or Mann-Whitney U test. P < 0.05 was considered as statistically signi cant.

Results
3.1 Basic information of patients The age composition of the patients in the 2 cohorts was statistically signi cant (P < 0.05), and the age of the patients who underwent LESS surgery (27.6 ± 8.4) tended to be younger compared with those who underwent common laparoscopic surgery (40.9 ± 15.5); the body mass index, menstrual status, leading symptoms, ovarian cyst size, preoperative CA125 level and preoperative CA199 level of the patients in the 2 cohorts were not had statistically signi cant (P > 0.05). (Table 1)  3.2 Surgery-related data The differences in the operation time, intraoperative blood loss and intracystic uid spillage between the two cohorts had statistical signi cance (P < 0.05).The P value in the extent of surgical resection, postoperative evacuation time, intraoperative complications, postoperative complications, the application of postoperative analgesic drugs, and the length of postoperative hospital stay between the two cohorts was bigger than 0.05. There was no signi cant difference in the use of postoperative analgesic drugs between the two groups (P = 0.980), indicating that the postoperative pain of LESS surgery was not severe than that of the traditional laparoscopic group. Two patients had intraoperative change of surgical methods. One patient in the LESS cohort underwent fertility-sparing staged surgery with the addition of an auxiliary puncture port due to the possibility of borderline tumors suggested by intraoperative pathological ndings. One patient in traditional laparoscope cohort was transferred to laparotomy due to severe abdominal adhesion. One of the patients who underwent conventional laparoscopy accepted re-suture due to poor healing of the abdominal puncture site.
(  3.3 Pathological types There were no signi cant differences in postoperative routine pathological results between the two cohorts. One patient in the LESS cohort had intraoperative pathological ndings suggestive of borderline mucinous adenoma, and fertility-sparing staged surgery was performed intraoperatively based on this nding. The intraoperative pathological results of 2 patients with traditional laparoscopy suggested borderline mucinous adenoma, of which 1 patient underwent staged surgery, and the other one patient's families strongly requested waiting for the con rmation of routine pathological results.This patient underwent staged surgery after the pathological ndings were clear. (Table 3) 3.4 Postoperative follow-up After discharge, the patients whose nal histology diagnosis was benign visited the outpatient department once a month for reexamination for 3 consecutive times. During the follow-up, the well abdominal incision healed was observed. The menstruation of the patients of childbearing age who underwent ovarian cystectomy alone was the same as that before the operation, without other complications. The vaginal ultrasound showed no abnormality of the ovary. Postoperative follow-up for 6 months for the patient whose nal histology diagnosis was borderline, and relevant examination results didn't show any abnormal signal or disease progression.
For giant ovarian cysts, there are some experts who believe that cysts larger than 10 mm in diameter are contraindications for laparoscopic surgery.Because the pelvic cavity is occupied by cysts ,the operable space is narrow and the anatomical position of the abdominopelvic cavity cannot be fully exposed, it is easy to lead to surrounding organ injury and cyst rupture [9].In order to solve the problem many obstetricians and gynecologists have explored. For example, ultrasound-guided technique was applied preoperatively for cyst uid aspiration, or a second ,third trocar was used to puncture the cyst wall into the cyst cavity to aspirate the uid [10,11] .Relevant literature reports have demonstrated that the size of ovarian cysts is not an absolute contraindication for laparoscopic surgery [12].However, such reports showed that there was spillage of cyst uid into the abdominal cavity [9,12].
Relevant studies have shown that large-diameter cysts are closely related to the occurrence of malignant tumors, and the rupture of malignant tumors will reduce the long-term survival rate of patients, which indicates that it is essential to effectively ensure the integrity of cysts during surgery [13].Compared to conventional laparoscopy, the LESS surgery can enter the abdominal cavity under direct vision.And using sterile gauze wraps around inner edge of wound distractor .This two methods can effectively prevent ovarian cyst rupture as well as cyst spillage. None of the 30 patients who underwent LESS in this study had intraoperative cystic uid spillage, which con rmed the safety of LESS surgery in this area compared with the spillage rate of 19.6% in the traditional laparoscopic cohort. In recent years, the application of local skin adhesive in LESS surgery for large ovarian cysts has emerged as a leak-proof technique, and relevant studies have also suggested signi cant effect [14], which providing more ideas and methods for LESS surgery in giant ovarian cyst surgery in the future.
Surgical procedures in the general laparoscopic group required prolonged maintenance of pneumoperitoneum ,which could increases the risk of tumor dissemination If the ovarian tumor is borderline or malignant [15,16].At the same time, specimen removal is also a di cult pace under traditional laparoscopic surgery with the smaller puncture which usually from 5mm to 12mm.The length of abdominal incision in LESS surgery is about 2-3 cm, which is longer than that of traditional laparoscopic. Under LESS, the ovarian cyst wall can be gradually lifted to the outside of the abdominal cavity to complete ovarian cystectomy and ovarian repair under direct vision, reducing the time of operation exposed to pneumoperitoneum, not only reducing the electrolyte imbalance of patients caused by CO 2 diffusion into the blood [17], but also reducing the possibility of tumor dissemination due to the chimney effect. A Meta-analysis showed that electrocoagulation hemostasis had a negative effect on ovarian reserve and the effect can lasted for a long time [18].Operative performed outside the abdominal cavity in LESS reduced the use of electrical devices can better protects the ovarian reserve [19,20,21].
Conventional laparoscopy should have 3-5 puncture holes upon to the surgical operation needs. LESS surgery is performed using the umbilicus of the human body, and the special physiological conditions can largely cover the surgical incision scar ,which is more in line with the pursuit of minimally invasive [7,23] .In this study, patients in both cohorts voluntarily chose the surgical method. The statistical results showed that there was statistical signi cant in the age composition of the two cohorts (P < 0.05), suggesting that in the selection of surgical approach for giant ovarian cyst, younger women were more likely to choose LESS, which may be related to they pay more attention to their own image [23].And there was no signi cant difference between the two cohorts in terms of basic information and pathological type except for age.
A prospective analysis of 21 patients with ovarian cysts ≥ 15 cm in diameter who underwent LESS showed that the median operation time was 79.8 min (39-155 min), blood loss was 60 mL (10-180 mL); postoperative hospital stay was (2.7 ± 0.6) d (2-4 d); 1 patient (5%) had postoperative scar hematoma; more than 71% of patients were satis ed with the occult scar after logarithm [24].In contrast, in this study, the operation time of LESS surgery was 80 min (55-135 min), which may be because all patients were not operated by the same surgeon and it included the intraoperative waiting time for frozen pathology.
The intraoperative blood loss was 17.5ml (10-22.5ml).one patient(2.2%) in control cohorts exhibited wound problem. The length of hospital stay 3 days (2-5d) after surgery may be related to the health insurance system in China, cause patients tend to wait for routine pathological results before discharge.
Combined with relevant reports and this study, the results demonstrated that LESS surgery in the treatment of giant ovarian cyst has the characteristics of save operation time, less bleeding, shorter exhaust time, less postoperative complications, high scar aesthetics satisfaction, etc. Therefore, after adequate evaluation and screening of patients, the size of ovarian cyst cannot be used as the reason for rejecting LESS surgery, which is safe and feasible for clinical promotion in the treatment of giant ovarian cyst. However, the sample size of relevant studies in this study is small and there is a lack of largesample data analysis, and more prospective studies are needed in order to obtain more de nite conclusions. She is good at hysteroscopic and laparoscopic minimally invasive surgery and the diagnosis and treatment of benign and malignant gynecological tumors, and took the lead in carrying out pneumoperitoneum free ovarian cancer surgery and single-incision mid-urethral tension-free suspension and other surgeries. She has been engaged in the clinical, teaching and scienti c research of obstetrics and gynecology for more than 20 years, and has undertaken the theoretical and clinical teaching tasks of obstetrics and gynecology for graduate students, undergraduate students and international students. Picture A and Picture B