The role of virtual reality simulation in surgical training in the light of COVID-19 pandemic: Visual spatial ability as a predictor for improved surgical performance: a randomized trial.

INTRODUCTION: Due to the current COVID-19 pandemic, surgical training has become increasingly challenging due to required social distancing. Therefore, the use of virtual reality (VR)-simulation could be a helpful tool for imparting surgical skills, especially in minimally invasive environments. Visual spatial ability (VSA) might influence the learning curve for laparoscopic surgical skills. However, little is known about the influence of VSA for surgical novices on VR-simulator training regarding the complexity of different tasks over a long-term training period. Our study evaluated prior VSA and VSA development in surgical trainees during VR-simulator training, and its influence on surgical performance in simulator training. METHODS: In our single-center prospective two-arm randomized trial, VSA was measured with a tube figure test before curriculum training. After 1:1 randomization, the training group (TG) participated in the entire curriculum training consisting of 48 different VR-simulator tasks with varying difficulty over a continuous nine-day training session. The control group (CG) performed two of these tasks on day 1 and 9. Correlation and regression analyses were used to assess the influence of VSA on VR-related surgical skills and to measure procedural abilities. RESULTS: Sixty students (33 women) were included. Significant improvements in the TG in surgical performance and faster completion times were observed from days 1 to 9 for the scope orientation 30° right-handed (SOR), and cholecystectomy dissection tasks after the structured 9-day training program. After training, the TG with pre-existing low VSA scores achieved performance levels similar to those with pre-existing high VSA scores for the two VR simulator tasks. Significant correlations between VSA and surgical performance on complex laparoscopic camera navigation SOR tasks were found before training. CONCLUSIONS: Our study revealed that that all trainees improved their surgical skills irrespective of previous VSA during structured VR simulator training. An increase in VSA resulted in improvements in surgical performance and training progress, which was more distinct in complex simulator tasks. Further, we demonstrated a positive relationship between VSA and surgical performance of the TG, especially at the beginning of training. Our results identified pre-existing levels of VSA as a predictor of surgical performance.

Stress biomarkers in minimally invasive and conventional colorectal resections.

INTRODUCTION: Any surgical procedure develops a stress situation for the patient, which can modulate the individual outcome. At present, there is only limited information about stress response in colorectal resections by laparoscopic compared to conventional surgery. Therefore, our objectives were the feasibility and the investigation of stress biomarkers including copeptin and steroid hormones before, during and after colorectal surgery. METHODS: Eleven patients underwent minimally invasive and ten patients conventionally open colorectal surgery. Blood samples were collected before, during and 24 h after surgery and copeptin, NT-proBNP, cortisol, cortisone, interleukin-6 and glucose were analyzed. RESULTS: Both, minimally invasive and conventional-open colorectal surgery caused a fast but heterogeneous response of stress biomarkers. However, the postoperative decrease of cortisol, cortisone and glucose differed between both groups. The stress biomarkers decreased faster down to baseline after minimally invasive surgery, while in open surgery cortisol, cortisone and glucose did not return to baseline within 24 h after operation. CONCLUSIONS: We show in this feasibility study for the first time an increase of copeptin in combination with glucocorticoids as stress biomarkers by open surgery compared to minimally invasive procedures in patients undergoing colorectal surgery. Exceeding an individual threshold of 'stress burden' may have unfavorable effects on the long-time clinical outcome.

Total mesorectal excision--does the choice of dissection technique have an impact on pelvic autonomic nerve preservation?

BACKGROUND: The aim of this experimental study was to assess the quality of pelvic autonomic nerve preservation of different dissection techniques. MATERIAL AND METHODS: Twelve pigs underwent low anterior rectal resection (LARR) with scissors, ultracision, monopolar diathermy, and waterjet, each in three animals. Assessment of pelvic autonomic nerve preservation was carried out by stimulation of the pelvic splanchnic nerves under electromyography of the internal anal sphincter (IAS). Neurostimulation was performed bilaterally after posterior dissection, after complete mesorectal dissection, and after rectal resection. RESULTS: Stimulation resulted in significantly increased amplitudes of the time-based electromyographic signal of the IAS, confirming nerve preservation. The stimulation results after complete mesorectal dissection showed comparable median amplitude increases for dissection with scissors (10.34 µV (interquartile range [IQR], 5.58; 14.74)) and ultracision (9.79 µV (IQR, 7.63; 11.6)). Lower amplitude increases were observed for monopolar diathermy (4.47 µV (IQR, 2.52; 10.46)) and waterjet (0.61 µV (IQR, 0.07; 2.11)) (p = 0.038). All animals undergoing dissection with scissors, ultracision, and monopolar diathermy had bilateral positive results. Of three animals undergoing LARR with waterjet, one had bilateral positive results. Two had unilateral negative results, indicating incomplete nerve preservation. CONCLUSION: Scissors, ultracision, and monopolar diathermy might have comparable nerve-sparing potentials and differed from waterjet.

Total mesorectal excision with intraoperative assessment of internal anal sphincter innervation provides new insights into neurogenic incontinence.

BACKGROUND: The aim of this prospective study was to assess internal anal sphincter (IAS) innervation in patients undergoing total mesorectal excision (TME) by intraoperative neuromonitoring (IONM). STUDY DESIGN: Fourteen patients underwent TME. IONM was carried out through pelvic splanchnic nerve stimulation under continuous electromyography of the IAS. Anorectal function was assessed with the digital rectal examination scoring system and a standardized questionnaire. RESULTS: Nine of 11 patients who underwent low anterior resection had positive IONM results, with stimulation-induced increased IAS electromyographic amplitudes (median 0.23 µV (interquartile range [IQR] 0.05, 0.56) vs median 0.89 µV (IQR 0.64, 1.88), p < 0.001) after TME. The patients with the positive IONM results were continent after stoma closure. Of 2 patients with negative IONM results, 1 had fecal incontinence after closure of the defunctioning stoma and received a permanent sigmoidostomy. In the other patient the defunctioning stoma was deemed permanent due to decreased anal sphincter function. In 3 patients who underwent abdominoperineal excision, IONM assessed denervation of the IAS after performance of the abdominal part. CONCLUSIONS: This study demonstrated that IONM of IAS innervation in rectal cancer patients is feasible and may predict neurogenic fecal incontinence.