Discrimination between arterial and venous bowel ischemia by computer-assisted analysis of the fluorescent signal In the original version, Ines Gockel was omitted as a coauthor. The complete author listing is corrected here.

Correction to: Safety of orogastric tubes in foregut and bariatric surgery The article “Safety of orogastric tubes in foregut and bariatric surgery,” written by Kulvir Nandra and Richard Ing, was originally published Online First without Open Access. After publication in volume 32, issue 10, pages 4068–4070, the authors decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed to © The Author(s) 2018 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Occult contralateral inguinal hernias: what is their true incidence and should they be repaired? Abstract Background The true incidence of occult contralateral inguinal hernia is unknown; however, when found, there exists controversy as to whether or not they should be repaired. The aim of our study is to identify the incidence of contralateral incidental inguinal hernias in our surgical population, compare our results to previous studies timelining occult hernia identification to repair need, and generate debate as to whether incidental contralateral hernias should be repaired at the index operation. Methods We reviewed the charts of 297 consecutive patients undergoing robotic inguinal hernia repair between October 2014 and April 2018 at a single facility. By comparing preoperative physical examination to intraoperative findings, we determined the number of occult contralateral inguinal hernias in our patient population. Results Of 297 patients, 158 (53.2%) presented with a right inguinal hernia, 90 (30.3%) presented with a left inguinal hernia, and 49 (16.5%) presented with bilateral inguinal hernias. Forty-seven of the 297 patients (15.8%) were found to have an incidental contralateral inguinal hernia. Excluding patients with known bilateral inguinal hernias, 20% of patients with a left inguinal hernia were found to have an occult right inguinal hernia and 18.4% of patients with a right inguinal hernia were found to have an occult left inguinal hernia. Conclusions The true incidence of occult contralateral inguinal hernia may be higher than originally thought. When inguinal hernia repair is performed through a transabdominal approach, these occult hernias may be easily addressed during the same operation without additional skin incisions. This may ultimately prevent the morbidity of developing a metachronous hernia that requires repair.

Competency assessment for gastric endoscopic submucosal dissection using an endoscopic part-task training box Abstract Background Objective assessment of endoscopist competency is important. Recently, the endoscopic part-task training box (Thompson Endoscopic Skills Trainer [TEST]) was developed to assess endoscopist competency. We aimed to evaluate the ability of the TEST to assess competency during endoscopic procedures, especially endoscopic submucosal dissection (ESD). Methods Twenty-three physicians were included in this study. Correlations between TEST scores and the following factors were evaluated: years of endoscopic experience, number of esophagogastroduodenoscopies (EGDs) performed, number of colonoscopies (CSs) performed, cecal intubation rate, number of gastric ESDs performed, gastric ESD procedure time/lesion size (min/mm2), and gastric ESD self-completion rate. Also, correlation coefficients between the number of gastric ESDs performed and each of gastric ESD procedure time/lesion size and gastric ESD self-completion rate were calculated. Results TEST scores showed strong correlations to different factors: years of experience in endoscopy: 0.957 (p < 0.01); number of EGDs: 0.947 (p < 0.01); number of CSs: 0.947, (p < 0.01); number of gastric ESDs: 0.924 (p < 0.01); gastric ESD procedure time/lesion size: − 0.9 (p < 0.01); self-completion rate of gastric ESDs: 0.857 (p < 0.005). The number of gastric ESDs performed was not more strongly correlated to procedure time of gastric ESDs or self-completion rate of gastric ESDs compared to TEST scores (− 0.824 (p < 0.01) and 0.704 (p < 0.05), respectively). TEST scores of endoscopists with a cecal intubation rate ≥ 90% were > 380, while the scores of physicians with a gastric ESD self-completion rate ≥ 90% were > 700. Conclusions TEST score correlates with both basic and advanced endoscopic procedures. TEST is therefore a promising option for assessing endoscopist competency, and might be useful for providing threshold scores as competency markers for specific endoscopic procedures such as gastric ESD.

Correction to: Validation of a virtual intracorporeal suturing simulator The surname of Sreekanth Arikatla incorrectly appeared as Sreekanth Artikala.

Transanal total mesorectal excision (TaTME) versus laparoscopic TME for MRI-defined low rectal cancer: a propensity score-matched analysis of oncological outcomes Abstract Background While a shift to minimally invasive techniques in rectal cancer surgery has occurred, non-inferiority of laparoscopy in terms of oncological outcomes has not been definitely demonstrated. Transanal total mesorectal excision (TaTME) has been pioneered to potentially overcome difficulties experienced when operating with a pure abdominal approach deep down in the pelvis. This study aimed to compare short-term oncological results of TaTME versus laparoscopic TME (lapTME), based on a strict anatomical definition for low rectal cancer on MRI. Methods From June 2013, all consecutive TaTME cases were included and compared to lapTME in a single institution. Propensity score-matching was performed for nine relevant factors. Primary outcome was resection margin involvement (R1), secondary outcomes included intra- and post-operative outcomes. Results After matching, forty-one patients were included in each group; no significant differences were observed in patient and tumor characteristics. The resection margin was involved in 5 cases (12.2%) in the laparoscopic group, versus 2 (4.9%) TaTME cases (P = 0.432). The TME specimen quality was complete in 84.0% of the laparoscopic cases and in 92.7% of the TaTME cases (P = 0.266). Median distance to the circumferential resection margin (CRM) was 5 mm in lapTME and 10 mm in TaTME (P = 0.065). Significantly more conversions took place in the laparoscopic group, 9 (22.0%) compared to none in the TaTME group (P < 0.001). Other clinical outcomes did not show any significant differences between the two groups. Conclusion This is the first study to compare results of TaTME with lapTME in a highly selected patient group with MRI-defined low rectal tumors. A significant decrease in R1 rate could not be demonstrated, although conversion rate was significantly lower in this TaTME cohort.

Objective assessment of surgical skill transfer using non-invasive brain imaging Abstract Background Physical and virtual surgical simulators are increasingly being used in training technical surgical skills. However, metrics such as completion time or subjective performance checklists often show poor correlation to transfer of skills into clinical settings. We hypothesize that non-invasive brain imaging can objectively differentiate and classify surgical skill transfer, with higher accuracy than established metrics, for subjects based on motor skill levels. Study design 18 medical students at University at Buffalo were randomly assigned into control, physical surgical trainer, or virtual trainer groups. Training groups practiced a surgical technical task on respective simulators for 12 consecutive days. To measure skill transfer post-training, all subjects performed the technical task in an ex-vivo environment. Cortical activation was measured using functional near-infrared spectroscopy (fNIRS) in the prefrontal cortex, primary motor cortex, and supplementary motor area, due to their direct impact on motor skill learning. Results Classification between simulator trained and untrained subjects based on traditional metrics is poor, where misclassification errors range from 20 to 41%. Conversely, fNIRS metrics can successfully classify physical or virtual trained subjects from untrained subjects with misclassification errors of 2.2% and 8.9%, respectively. More importantly, untrained subjects are successfully classified from physical or virtual simulator trained subjects with misclassification errors of 2.7% and 9.1%, respectively. Conclusion fNIRS metrics are significantly more accurate than current established metrics in classifying different levels of surgical motor skill transfer. Our approach brings robustness, objectivity, and accuracy in validating the effectiveness of future surgical trainers in translating surgical skills to clinically relevant environments.

An analysis of results in a single-blinded, prospective randomized controlled trial comparing non-fixating versus self-fixating mesh for laparoscopic inguinal hernia repair Abstract Background It remains unclear whether use of self-fixating mesh during laparoscopic inguinal hernia repair (LIHR) impacts postoperative quality of life (QoL). We hypothesize patients receiving self-fixating mesh during totally extraperitoneal (TEP) LIHR will report less pain and improved QoL compared to those receiving non-fixating mesh. Methods An IRB-approved, single-blinded randomized controlled trial was conducted. Patients with primary, unilateral inguinal hernias were randomized to receive either non-fixating (control) or self-fixating mesh. Clinical visits were conducted 3 weeks and 1 year after LIHR. A validated Surgical Outcomes Measurement System (SOMS) instrument was used to assess patients’ QoL preoperatively and postoperatively along with Carolinas Comfort Scale (CCS) at 3 weeks and 1 year after surgery. Comparisons between self-fixating and non-fixating mesh groups were made using Chi-square, Wilcoxon rank-sum or independent samples t tests. Results Two hundred and seventy patients were enrolled (137 non-fixating vs 133 self-fixating). Preoperatively, there was no difference in mean age, BMI, or median hernia duration between groups (57.9 vs 56.6 years, p = 0.550; 26.1 vs 26.8, p = 0.534; 3.0 vs 3.0 months, p = 0.846). Median operative times (34 vs 34 min, p = 0.545) and LOS were similar. More patients in the non-fixating group received tacks (43 vs 19, p = 0.001). Patients receiving non-fixating mesh recorded better mean SOMS scores for the first 3 days following surgery (Day 1: p = 0.005; Day 2: p = 0.002; Day 3: p = 0.024, Table 1) indicating less pain. No differences in pain were seen 3 weeks or 1 year postoperatively. There were zero recurrences found during clinical follow-up in either of the groups. Conclusions Patients receiving self-fixating mesh report worse postoperative pain in the first 2–3 days than those receiving non-fixating mesh. The groups showed no differences across QoL metrics (SOMS and CCS) at 3 weeks or 1 year postoperatively. Self-fixating mesh does not appear to positively impact QoL after TEP LIHR.

Open versus laparoscopic hepatic resection for hepatocellular carcinoma: a systematic review and meta-analysis Abstract Background Several studies have been conducted comparing laparoscopic liver resection (LLR) versus open liver resection (OLR) for hepatocellular carcinoma (HCC), however, the optimal therapeutic approach has not been established. Therefore, we conducted a systematic review and meta-analysis of studies comparing LLR versus OLR for HCC. Methods MEDLINE and Cochrane Central Register of Controlled Trials database were systematically searched for relevant studies. Results Fifty-one studies were identified including a total of 6812 patients (2786 patients underwent LLR and 4026 patients were subjected to OLR). Blood transfusion rate, hospital stay in days, 30-days mortality rate and morbidity were significantly lower in LLR comparing with OLR (odds ratio (OR) 0.45; 95% confidence interval (CI) 0.30–0.69; P = 0.001; I2 = 55.83%), (MD − 3.87; 95% CI − 4.86 to − 2.89; P = 0.001; I2 = 87.35%), (OR 0.32; 95% CI 0.16–0.66; P = 0.001; I2 = 0%), and (OR 0.42; 95% CI 0.34–0.52; P = 0.001; I2 = 39.64), respectively. There was no significant difference between LLR and OLR regarding the operative time in minutes, resection margin in centimeter and R0 resection (MD 18.29; 95% CI − 1.58 to 38.15; p = 0.07; I2 = 91.73%), (MD 0.04; 95% CI − 0.06 to 0.14; P = 0.41; I2 = 48.03%) and (OR 1.31; 95% CI 0.98–1.76; P = 0.07; I2 = 0%), respectively. The 1-year overall survival (1-OS) and 5-OS rates were significantly higher in LLR comparing with OLR (OR 1.45; 95% CI 1.06–1.99; P = 0.02; I2 = 25.59%) and (OR 1.36; 95% CI 1.07–1.72; P = 0.01; I2 = 14.88%), respectively. Conclusion LLR is superior to OLR regarding intraoperative blood loss, blood transfusion rate, hospital stay in days, 30-days mortality and morbidity, however, randomized controlled trials are needed to identify the superiority of either strategy.

Impact of vagus nerve integrity testing on surgical management in patients with previous operations with potential risk of vagal injury Abstract Background Thoracic and foregut operations can cause vagal nerve injury resulting in delayed gastric emptying or gastroparesis. However, the cause of gastroparesis in these patients is not always from a vagal injury. We hypothesize that vagal nerve integrity (VNI) testing may better define who has vagal nerve dysfunction. This information may change subsequent operations. The aim of this study was to evaluate the impact of VNI testing in patients with prior thoracic or gastric surgery. Methods From January 2014 to December 2017, patients who had previous operations with the potential risk of vagal injury and had VNI testing were reviewed. Excluded patients were those with no plan for a second operation or the second operation was only for gastroparesis. The main outcome was the percentage of operations altered due to the results of VNI testing. Results Twelve patients (eight females) were included. Ages ranged from 37 to 77 years. VNI results were compatible with vagal injury in eight patients (67%). VNI test results altered subsequent operative plans in 41.7% (5/12). Pyloroplasty was done in addition to fundoplication in two patients. Plans for hiatal hernia repair with or without redo-fundoplication in three patients were changed by an additional pyloroplasty in one patient and partial gastrectomy with Roux-en-Y reconstruction in two patients. All patients who had secondary surgery had resolution of symptoms and improvement in objective testing. Conclusion The addition of VNI testing in patients with a previous potential risk of vagal nerve injury may help the surgeon select the appropriate secondary operation.