1.1 Hysterectomy

vNOTES hysterectomy has emerged as a new technique in the field of gynecology. Recently, several studies were conducted to study the feasibility, safety and application of this procedure.¹⁴ In a review of 33 studies including 384 hysterectomies, vNOTES hysterectomy was proven to be a safe procedure.¹⁵ Given the fact that vNOTES is less invasive, the introduction of vNOTES decreased the number laparoscopic transabdominal hysterectomies, though it did not decrease the number of classical vaginal hysterectomies.¹⁶

The first hysterectomy to be performed by vNOTES was actually a successful hybrid vNOTES without conversion to laparoscopy or laparotomy.¹⁷ Hybrid vNOTES was found to be more efficient compared to laparoscopically-assisted vaginal hysterectomy as the size of the uterus increases.¹⁸ Later, Baekelandt was the first to report the feasibility of pure vNOTES hysterectomy. He demonstrated that the procedure can be performed successfully, while reporting no intra-operative complications. Mean operative time was 97 ​min, but the main advantage was the reduced post-operative pain scores.¹⁶

In a prospective case series of 33 patients, vNOTES hysterectomy was shown to combine both the advantages of vaginal surgery and laparoscopy. Compared to conventional laparoscopic hysterectomy, it allowed for a better access into internal organs, overcame the limits presented by minimal uterine descent, limited gas insufflation, and favored a moderate Trendelenburg positioning over the overt one applied in conventional laparoscopy.⁹ Additional advantages include better operative outcomes, shorter operative time, lower estimated blood loss, and shorter post-operative hospital stay.¹⁸ While avoiding abdominal wall incisions, inexpensive conventional laparoscopy instruments can be safely used for vNOTES hysterectomy. Thus, reasonable costs can be combined with operative superiority and higher post-operative patient satisfaction, namely when it comes to pain reduction and cosmetics.⁵ vNOTES allows the surgeon to clearly survey and access the pelvis after completion of vaginal hysterectomy without any additional abdominal incisions. Thus, vNOTES should always be considered as a rescue surgery after vaginal hysterectomy for pelvic procedures.¹⁹ Also, vNOTES subtotal hysterectomy can be a safe option in case the cervix is to be preserved.²⁰

In one study, vNOTES had a shorter operative time with a mean difference of 22.04 ​min, and a shorter length of hospital stay despite higher cost in hospital charges.²¹ Similarly, Housmans et al. reported a mean difference in operative time between vNOTES and the conventional laparoscopy approaches of 16.73 ​min, in favor of vNOTES being faster.²² On the other hand, in their review of 40 vNOTES hysterectomies and 120 laparoscopic assisted vaginal hysterectomies, Kim et al. found that LAVH had a mean operative time of 58.3min compared with 75.4min for vNOTES.²³

Several studies have been performed to compare vNOTES hysterectomy to conventional laparoscopic techniques in terms of complications. Baekelandt et al., 2017 reported no differences in post-operative complication rate between vNOTES and laparoscopic assisted vaginal hysterectomy.²¹ vNOTES has also led to less blood loss and a shorter hospital stay compared with.²² However, vNOTES procedure was superior in terms of bleeding loss.²³ In a large study where 750 patients underwent vNOTES hysterectomies, the total complication rate was in total 5.2%, with 30-day post-operative complications being more frequent than intra-operative ones (3.8% versus 1.4%). Though the total incidence of complications in vNOTES hysterectomy was higher than that reported in all gynecologic vNOTES performed in the 1000 patients of the same study (5.2% versus 3.9%),²⁴ the 30-day complication rate of vNOTES hysterectomy is still lower than the 30-day post-operative complication rate of laparoscopic hysterectomy (8%) and abdominal hysterectomy (15%).²⁵

Interestingly, vNOTES hysterectomy was performed in female-to-male transgender men. Similar results were encountered between the vNOTES group and the conventional laparoscopy group in terms of operative time, estimated blood loss, and operative complications; however, post-operative pain was significantly reduced in the vNOTES group.²⁶

One specific limitation in vNOTES hysterectomy is the disproportion between uterine tumor size and vaginal dimensions.²⁷ Though one study showed that vNOTES hysterectomy for uteri larger than 1000g can be still feasible and safe,²⁸ larger uterine masses may increase operative time and estimated blood loss.^29,30

The first robotic vNOTES hysterectomy was performed in 2015 by replacing the conventional endoscope used previously in such procedures. Operative time was much higher than the previously described values, at 198.8 ​± ​39.0 ​min. This can be explained by the fact that proper instrumentation was not yet available for robotic vNOTES. However, using the curved cannula-wristed instrument, robotic vNOTES allows for accessing deeper locations and resecting larger tumors. Thus, the use of this technique should limited to certain circumstances and patient population.³¹ Three years later, flexible robotic vNOTES hysterectomy was introduced into gynecologic surgeries using the Flex® Robotic System with Colorectal Drive. The surgery was successfully performed with operative time of 78min, although laparoscopic assistance was needed for uterine manipulation.¹ Later, Yang et al. in 2019 reported that scarless and gasless robotic vNOTES hysterectomy is a feasible and safe procedure as a scarless and gasless surgical technique in their study conducted on 13 patients. Only one patient required laparoscopic assistance with zero conversion rate, and no post-operative complications were encountered.³² Then in 2020, Lowenstein et al. used the Hominis surgical system for robotic vNOTES hysterectomy. The system had light weight and small footprint, which ensured easy mobility and short setup time. All surgeries were performed completely using the system with no intra-operative complications. However, post-operative urinary tract infection occurred in 10% of the cases.³³

1.2 Salpingo-oophorectomy

Salpingo-oophorectomy via vNOTES after vaginal hysterectomy was well described in the literature.⁸ It is mainly performed following vaginal hysterectomy to avoid abdominal incisions,⁸ given the limitations that are overcome once the uterus is removed and a better view of the pelvis is achieved.³⁴ Though the adnexa are barely accessible through vaginal port without hysterectomy, vNOTES using colpotomy for adnexal procedures can be a solution when hysterectomy is to be avoided, like in ectopic pregnancy.³⁵

It is important to note that the limitations of adnexectomy using vNOTES are spillage, especially in the context of unexpected malignant tumors, and the presence of adhesions extending from the adnexa to the uterus or to the pelvic fascia.¹⁵

Though vNOTES has been used in general surgery for years, the first paper to describe adnexal procedures using NOTES was issued in 2012 and included 3 cases of tubal sterilization, 3 cases of salpingectomy for ectopic pregnancy, and 4 cases of enucleation of ovarian tumor. All were completed using vNOTES except for one case of ovarian tumor which was misdiagnosed and found to be an inaccessible mucinous tumor anterior to the uterus, thus conversion into transabdominal laparoscopy was warranted to avoid spillage.³⁶ In the same year, ovarian cystectomy, salpingectomy, salpingostomy, oophorectomy, para-tubal cystectomy and ovarian wedge resection were successfully performed via vNOTES, all in a single study.³⁷ Then in 2013, adnexectomy through vNOTES was again described in 7 patients. They successfully underwent vNOTES for adnexal masses without any post-operative complications and reported high level of satisfaction concerning the cosmetic outcome of the surgery.³⁸

vNOTES can decrease estimated blood loss (EBL), operative time (OT) and length of hospital stay. In one study, 33 patients were operated on using vNOTES for adnexectomy, while 203 patients underwent conventional laparoscopic adnexectomy. EBL in the vNOTES group was lower (14.0 ​mL vs 27.6 ​mL), operating time was shorter (39.2 ​min vs 51.9 ​mL), and hospital stay was reduced (1.4 days vs 2.1 days). However, hospital charges were much higher in the vNOTES group (p-value ​< ​0.05).³⁹ In a newer study including 33 patients who successfully submitted to adnexectomy, OT and EBL both decreased as surgeons performed more procedures, thus a good learning curve was established.⁹

A review paper compared vaginal ovarian cystectomy to conventional laparoscopic cystectomy for benign indications. 525 patients from 10 different studies were included, 299 of whom underwent laparoscopic ovarian cystectomy. 5 main approaches were utilized for vaginal ovarian cystectomy. They varied mainly by the technique of entering the cul-de-sac and the technique of cystectomy.⁴⁰ One of these techniques in the included studies was vNOTES.^41–43 In one study, 14 patients successfully underwent fertility-sparing vNOTES ovarian cystectomy for benign indications. In each patient, the cul-de-sac was accessed through a 2.5 ​cm colpotomy, and a vaginal NOTES port was introduced, through which the excised cyst was removed. No post-operative complications were reported.⁴² Wang et al. found no significant difference in costs between vNOTES for benign ovarian cystectomy and laparoscopic ovarian cystectomy. Though estimated blood loss (EBL) was significantly higher in vNOTES (31 ​mL versus 21 ​mL in laparoscopic approach, p-value of 0.028), the difference had no clinical impact. However, mean OT was reduced in the vNOTES group (n ​= ​34) compared to laparoscopic ovarian cystectomy group (n ​= ​243) (38 versus 54 ​min) (p-value<0.001).⁴³ A much higher mean OT (74 ​min) was observed by Ding et al. in 6 patients who underwent ovarian cystectomy using vNOTES.⁴¹ These studies showed that vNOTES can be a feasible approach for ovarian cystectomy.

A huge recent study included 1000 patients undergoing vNOTES, out of 270 patients submitted to pelvic surgeries without hysterectomy. Pelvic organs were accessed through a single 2.5 ​cm posterior colpotomy. Intraoperative complications were not reported, and post-operative complications were documented just in 0.4% of these cases, but none was of Clavien-Dindo grades 3 or 4.²⁴ Thus, vNOTES can be safely used in pelvic surgeries even without hysterectomy.

One important advantage of vNOTES is decreased post-operative pain. Salpingo-oophorectomy for benign indications was performed via vNOTES by a single surgeon on 6 different patients. Mean post-operative pain scores using visual analog scale were 4.1 ​at 6 ​h, 2.5 ​at 12 ​h and 0.67 ​at 24 ​h. Those scores were reduced in vNOTES given the absence of abdominal incisions.⁵ Similarly, in another study, pain scores were significantly lower in patients who underwent vNOTES salpingectomy compared to those who underwent conventional laparoscopic salpingectomy (2.22 ​± ​0.65 versus 2.75 ​± ​0.72), and patient cosmetic satisfaction was significantly higher post vNOTES, with p-value ​< ​0.05.⁴⁴ Also, salpingo-oophorectomy using vNOTES was performed in female-to-male transgender men, and significantly lower pain scores were recorded than conventional procedures of laparoscopy.²⁶

One technical problem in vNOTES is gas leakage, making the use of pneumoperitoneum impractical.¹⁴ However, gasless laparoscopy for salpingo-oophorectomy via vNOTES was described to be successfully performed in 10 patients, without the need of any abdominal incision or gas insufflation. The mean operative time was 22.2 ​min, with no intra-operative complications.¹³ Another advantage of gasless laparoscopy is avoiding the risks imposed by the use of intra-abdominal carbon dioxide, including subcutaneous emphysema, air embolism, hypercapnia, hemodynamic changes and cardiopulmonary dysfunction.⁴⁵

In 2018, the flexible robotic device approved by the FDA for colorectal surgery was used for the first time to perform 4 separate surgeries, one of which was salpingo-oophorectomy. The technique was called vaginal access minimally invasive surgery (VAMIS), where hysterectomy and right salpingo-oophorectomy were performed. Salpingo-oophorectomy was achieved in 13.5 ​min, totally using robotic VAMIS, but laparoscopic assistance was needed.¹ A newer study reported the successful use of robotic vNOTES for bilateral salpingo-oophorectomy on 8 women. Median operative time was 45 ​min, but it decreased as more surgeries were done indicating a reasonable learning curve for robotic vNOTES. Surgeon's usability assessment was made on a score from 1 to 5, with a median of 5 (good). This shows that robotic vNOTES can be taught and utilized in gynecologic surgeries.⁴⁶ Thus, flexible robotic system can be used in direct-target NOTES.

1.3 Ectopic pregnancy

Many studies have emphasized on the role of vNOTES (natural orifice transluminal endoscopic surgery), as an alternative to conservative treatment, for treating ectopic pregnancies in selected cases. Baekelandt et al. described the role of transvaginal hydrolaparoscopy (TVHL) in the diagnosis of pregnancy of unknown location (PUL) and the role of vNOTES in treating 12 patients with ectopic pregnancies (IMELDA technique). All women were successfully treated with a 2.5-cm colpotomy followed by vNOTES salpingectomy or salpingostomy. On the other hand, 3 women with PUL were explored with TVHL. All of those explorations were negative, leaving only a 4 ​mm perforation. On follow up, 2 of them had normal intrauterine pregnancies and one had persistent elevated hCG for which she has been treated with methotrexate.⁴⁷

Similarly, Chen et al. performed successful hybrid NOTES with trans-abdominal assistance on 4 patients, and pure NOTES on 8 cases with ectopic pregnancies. Conversion rate to traditional laparoscopy or laparotomy was zero, and peri-operative complications were not reported, with a median operative time of 47.5 ​min. None of them required laparotomy or laparoscopy. Post-operative pain scores were low, ranging between 1 and 3. To note that all of the included patients have had a previous vaginal delivery which could have enhanced elasticity.⁴⁸ More recently, a quick uncomplicated vNOTES procedure of 36-min duration was successfully performed on a 27-year-old gravida 3 para 0 woman, with a history of left salpingectomy, who presented for a left tubal stump pregnancy.⁴⁹

1.4 Myomectomy

We know of only 2 articles reporting the use of vNOTES for myomectomy. One study in 2017 included 8 patients treated for intramural, subserosal and pedunculated myomas. In case of a posterior myoma, a 2.5 ​cm posterior colpotomy was made, the pouch of douglas was opened and vNOTES port was inserted. In case of an anterior myoma, an anterior colpotomy was made, and vNOTES port was inserted. None had complications. The author advised to reduce the surgical time, in a first-world hospital, with the use of an autolocking suture and NOTES port. This article suggested that stage 3–7 myomas can be treated by a minimally invasive technique like vNOTES.⁵⁰

In the sam year, Liu et al. demonstrated a successful stepwise approach of applying transvaginal vNOTES in a 42-year-old lady, gravida 2, para 2, to remove a 6-cm left anterior myoma with uterine preservation. It was combined with a traditional transvaginal anterior colpotomy. The surgery resulted in the resolution of her pain with minimal blood loss.⁵¹

vNOTES for myomectomy allows the instruments to reach deeper location in the pelvis and hence resect larger myomas. This is attributed to vaginal flexibility that improves the extension of the colpotomy incision.¹⁵