Vaginal Natural Orifice Trans-luminal Endoscopic Surgery Salpingectomy for Tubal Sterilization: Clinical Outcomes and Learning Curve Analysis

The evolution from traditional open surgery to laparoscopic surgery has led to a significant reduction of morbidity and mortality. Newer advances such as development of single port laparoscopic surgery and scarless Natural Orifice Transluminal Endoscopic Surgery (NOTES) with or without robot assistance have moved forward the practice in "Minimally Invasive Surgery".

Described for the first time in 2004 at John Hopkins University in an experimental porcine model, NOTES is a surgical technique in which the natural orifices (mouth, vagina, urethra and rectum) are used as access routes to the peritoneal cavity for endoscopic surgery with no abdominal incisions.

Clinical application of NOTES has been initially reported in general surgical procedures where Trans-gastric Appendectomy and Cholecystectomy have been performed using the mouth and the stomach as the access route.

The technique seems to be feasible and safe when performed by experienced surgeons. Favourable outcomes such as reduced post-operative pain, a shorter length of hospital stay, improved cosmetic results due to scar-free surgery and reduced wound complications at trocar insertion sites, promote the increasing use of this new surgical technique.

Although NOTES may be performed through various entries including the stomach, oesophagus, bladder and rectum, NOTES procedures in women have been commonly performed through the vagina as this allows direct access to the abdominal cavity. Therefore, trans-vaginal NOTES (vNOTES) has gained popularity among general surgeons, urologists and gastroenterologists over the past decade and was adopted in various surgical procedures, varying from cholecystectomy, appendectomy, sigmoidectomy, nephrectomy, splenectomy, liver resection and sleeve gastrectomy.

Recently, clinical application of vNOTES has broadened significantly in the field of gynaecological surgery. The feasibility and safety of vNOTES in this specialty was firstly demonstrated in 2012. This event represented the key milestone in the evolution of vNOTES for gynaecologic procedures. Based on the current reports, we know that many of these procedures, such as oophorectomy, salpingectomy, adnexectomy, hysterectomy and many other more complex surgeries can be performed using vNOTES by the majority of surgeons who have adequate skills in performing laparoscopy.

As the application of vNOTES is increasing, it is deemed mandatory to assess the learning curve (LC) of this novel technique. This is particularly important in surgery where new skills must be acquired constantly, safely and proficiently. It would be useful to know how many vNOTES procedures a surgeon may have to carry out before reaching an adequate level of safety and efficiency. Furthermore, a correct understanding of the LC is essential in randomised control trials comparing vNOTES with alternative types of surgery in order to reach valid conclusions.

There is a paucity of reports in the literature analysing the LC of vNOTES. The "learning curves" for performing vNOTES hysterectomy and adnexal surgery have been previously assessed by retrospective studies, each conducted on a single surgeon basis and in a single institution (19-21). In a report published in June 2020, Lowenstein et al were among the first researchers that evaluated prospectively the learning curve of mastering the skills to perform vNOTES hysterectomy and uterosacral ligament suspension in two different centres.

To the investigators knowledge, there is no published prospective multicentre study that aims to evaluate the feasibility, the LC, the peri- and postoperative outcomes of salpingectomy for tubal sterilization by the technique of vNOTES.