vNOTES retroperitoneal sentinel lymph node dissection for endometrial cancer staging: First multicenter, prospective case series

INTRODUCTION

The current standard treatment for endometrial cancer is a laparoscopic hysterectomy with adnexectomies and bilateral sentinel node resection. A retroperitoneal vNOTES sentinel node resection has several theoretical potential advantages. These include being less invasive, leaving no visible scars, operating without Trendelenburg, and therefore offering the anesthetic advantage of easier ventilation in obese patients and following the natural lymph node trajectory from caudally to cranially and therefore a lower risk of missing the sentinel node. The aim of this study is to determine the feasibility of a retroperitoneal vNOTES approach to sentinel lymph node dissection for staging of endometrial cancer.

MATERIAL AND METHODS

A prospective multicenter case series was performed in four hospitals. A total of 64 women with early-stage endometrial carcinoma suitable for surgical staging with sentinel lymph node removal were operated via a transvaginal retroperitoneal vNOTES approach. The paravesical space was entered through a vaginal incision after injecting the cervix with indocyanine green. A vNOTES port was placed into this space and insufflation of the retroperitoneum was performed. Sentinel lymph nodes were identified bilaterally using near-infrared light followed by endoscopic removal of these nodes.

RESULTS

A total of 64 women with early-stage endometrial cancer underwent sentinel lymph node removal by retroperitoneal vNOTES technique. All patients also underwent subsequent vNOTES hysterectomy and bilateral salpingo-oophorectomy. The median age was 69.5 years, median total operative time was 126 min and the median estimated blood loss was 80 mL. In 97% of the cases bilateral sentinel nodes could be identified. A total of 60 patients had negative sentinel nodes, three had isolated tumor cells and one had macroscopically positive sentinel nodes. No complications with sequel occurred.

CONCLUSIONS

This prospective multicenter case series demonstrates the feasibility of the vNOTES approach for identifying and removing sentinel lymph nodes in women with endometrial carcinoma successfully and safely. vNOTES allows sole transvaginal access with exposure of the entire retroperitoneal space, following the natural lymph trajectory caudally to cranially, and without the need for a Trendelenburg position.

Implementation and validation of a retroperitoneal dissection curriculum

BACKGROUND

Competency-based education requires educators to use simulation training for the purposes of education and assessment of resident trainees. Research demonstrates that improvement in surgical skills acquired in a simulated environment is transferrable to the operative environment. Laparoscopic retroperitoneal dissection, opening the retroperitoneal space and identifying the ureter, is a fundamental skill for gynecologists. Integrating simulation models into a formal and comprehensive curriculum for teaching ureterolysis could translate to increased surgical competency.

OBJECTIVE

Our goal was to validate a comprehensive curriculum for laparoscopic retroperitoneal dissection for the purpose of identification of the ureter by evaluating intraoperative performance.

STUDY DESIGN

A comprehensive curriculum, encompassing didactic and technical skills components and using a previously developed pelvic model, was designed to teach laparoscopic ureterolysis. Novice surgeons (postgraduate years 3-5) were recruited. Participants completed precurriculum and postcurriculum multiple-choice questionnaires to evaluate a didactic component. Preperformance and postperformance on the model was video-recorded. As part of the technical component, participants received constructive feedback from expert surgeons on how to perform laparoscopic retroperitoneal dissection using the simulation model. Participants were then video-recorded performing laparoscopic retroperitoneal dissection in the operating room within 3 months of the curriculum. All videos were blindly assessed by an expert using the Objective Structured Assessment of Technical Skills tool. At the conclusion of the study, participants completed a course evaluation.

RESULTS

Thirty novice gynecologic surgeons were recruited. High baseline knowledge of ureteric anatomy and injury (multiple-choice question score median and interquartile range) still significantly increased from 7 (5-7.25) precurriculum to 8 (7-9) postcurriculum (P < .001). The median (interquartile range) technical Objective Structured Assessment of Technical Skills score increased significantly from 24.5 (23-28.25) precurriculum to 30 (29.75-32) postcurriculum (P < .001). Video-recordings were completed for 23 participants performing laparoscopic retroperitoneal dissection in the operating room. Intraoperative Objective Structured Assessment of Technical Skills scores (median of 29 [interquartile range 27-32]) correlated with postcurriculum Objective Structured Assessment of Technical Skills scores on the model (r = 0.53, P = .01). The ureter was identified intraoperatively by 91% (n = 21/23) of participants. The majority of residents (81%, n = 21/26) were more comfortable completing a supervised retroperitoneal dissection as a result of participating in the curriculum. Residents believed that this model would be useful to enhance skills acquisition prior to performing the skill in the operating room (65%, n = 17/26).

CONCLUSION

A comprehensive retroperitoneal dissection curriculum showed improvement in cognitive knowledge and technical skills, which also translated to competent performance in the operating room. In addition to the objective measures, residents believed that their skills acquisition was improved following course completion.

The development of a retroperitoneal dissection model

Knowledge of ureteric anatomy is essential for ureteric injury prevention in laparoscopic gynecologic surgery. Rates of injury increase with limited surgical experience and reduced surgical volume. Currently, there are no low-fidelity or high-fidelity simulation models for teaching and practicing ureteric dissection. Our goal was to design a laparoscopic simulation model for retroperitoneal anatomy with high face validity that is low-cost and easily reproducible. A low-fidelity 3-dimensional simulation model was developed that represents key anatomic structures encountered during retroperitoneal dissection and ureteric identification. Materials, construction steps, and costs were determined. The models were trialed by expert laparoscopic surgeons. Demographic information that included age, gender, surgical experience, and complex laparoscopic case volumes was collected. Face validity was assessed with a 5-item Likert-scale. The total cost of 1 model ranged from $65 to $75. The majority of the materials that were used were reusable, except for 2 components that cost <$1 per use. Seven expert surgeons participated in the study, all of whom were fellowship-trained minimally invasive gynecologic surgeons or currently enrolled in this type of fellowship program. Participants agreed or strongly agreed that the model resembled the texture of the ureter, vessels, and peritoneal layer (n=6; 86%), approximated the correct anatomic course of the ureter (n=7; 100%), and closely approximated live surgery (n=5; 71%). They also agreed or strongly agreed that the model would be useful for teaching laparoscopic retroperitoneal dissection (n=7; 100%), for assessing a learner's ability before performing in the operating room (n=6; 86%), was low-cost (n=7; 100%), and was easily reproducible (n=6; 86%). This unique model fills a gap in laparoscopic simulation training. No other low- or high-fidelity models for laparoscopic retroperitoneal ureteric dissection have been identified in the literature. This simulation model is low-cost, easily reproducible, closely resembles retroperitoneal dissection during laparoscopic gynecologic surgery, and can be used for education and assessment.