Matthew J. Frelich

Current state of virtual reality simulation in robotic surgery training: a review

BackgroundWorldwide, the annual number of robotic surgical procedures continues to increase. Robotic surgical skills are unique from those used in either open or laparoscopic surgery. The acquisition of a basic robotic surgical skill set may be best accomplished in the simulation laboratory. We sought to review the current literature pertaining to the use of virtual reality (VR) simulation in the acquisition of robotic surgical skills on the da Vinci Surgical System.Materials and methodsA PubMed search was conducted between December 2014 and January 2015 utilizing the following keywords: virtual reality, robotic surgery, da Vinci, da Vinci skills simulator, SimSurgery Educational Platform, Mimic dV-Trainer, and Robotic Surgery Simulator. Articles were included if they were published between 2007 and 2015, utilized VR simulation for the da Vinci Surgical System, and utilized a commercially available VR platform.ResultsThe initial search criteria returned 227 published articles. After all inclusion and exclusion criteria were applied, a total of 47 peer-reviewed manuscripts were included in the final review.ConclusionsThere are many benefits to utilizing VR simulation for robotic skills acquisition. Four commercially available simulators have been demonstrated to be capable of assessing robotic skill. Three of the four simulators demonstrate the ability of a VR training curriculum to improve basic robotic skills, with proficiency-based training being the most effective training style. The skills obtained on a VR training curriculum are comparable with those obtained on dry laboratory simulation. The future of VR simulation includes utilization in assessment for re-credentialing purposes, advanced procedural-based training, and as a warm-up tool prior to surgery.

The relationship between duration of stay and readmissions in patients undergoing bariatric surgery

BACKGROUND Hospital readmissions are a quality indicator in bariatric surgery. In recent years, duration of stay after bariatric surgery has trended down greatly. We hypothesized that a shorter postoperative hospitalization does not increase the likelihood of readmission. METHODS The University HealthSystem Consortium (UHC) is an alliance of academic medical centers and affiliated hospitals. The UHCs clinical database contains information on inpatient stay and returns (readmissions) up to 30 days after discharge. A multicenter analysis of outcomes was performed by the use of data from the January 2009 to December 2013 for patients 18 years and older. Patients were identified by bariatric procedure International Classification of Diseases, Ninth Revision, codes and restricted by diagnosis codes for morbid obesity. RESULTS A total of 95,294 patients met inclusion criteria. The mean patient age was 45.4 (±0.11) years, and 73,941 (77.6%) subjects were female. There were 5,423 (5.7%) readmissions within the study period. Patients with hospitalizations of 3 days and more than 3 days were twice and four times as likely to be readmitted than those with hospitalizations of one day, respectively (P < .001). CONCLUSION Patients with longer postoperative hospitalizations were more likely to be readmitted after bariatric surgery. Early discharge does not appear to be associated with increased readmission rates.

Gastrojejunostomy technique and anastomotic complications in laparoscopic gastric bypass

BACKGROUND Various surgical techniques exist to create the gastrojejunostomy during laparoscopic Roux-en-Y gastric bypasses (LRYGB). A hand-sewn anastomosis (HSA) and circular-stapled anastomosis (CSA) are both common techniques. We hypothesized that the CSA was associated with a greater incidence of anastomotic complications. As a secondary aim, we sought to determine if weight loss varied by technique. METHODS This study is a retrospective review of patients who underwent primary LRYGB at the Medical College of Wisconsin from January 2010 to December 2011. Procedures were performed by one of 2 surgeons, each with a preferred gastrojejunostomy technique. Clinical information and patient outcomes were followed up to one year. RESULTS A total of 190 patients underwent LRYGB during the study interval. The majority of patients underwent HSA. Forty-one of 190 (21.6%) patients experienced one or more complications. Most complications were Clavien Classification Grade III and were experienced within 30 days of surgery in 3 (2.2%) HSA patients and 6 (10.9%) CSA patients (P = .02). Anastomotic complications occurred more frequently with the CSA technique (marginal ulcer 5.5% CSA versus .7% HSA; P = .04 and stenosis 16.4% CSA versus 3% HSA; P = .01). There were no gastrojejunostomy leaks in this series. Operative time was significantly longer in HSA patients (204 minutes HSA versus 166 minutes CSA; P<.01), but length of hospital stay did not differ. Weight loss at 12 months was similar between techniques (69.4% percent excess BMI lost (EBMIL) HSA versus 76.6% EBMIL CSA; P = .11). No patients were lost to follow-up at 30 days. Thirty-five patients (19%) were lost to follow-up by one year. CONCLUSION The CSA technique of gastrojejunostomy in gastric bypass is associated with a higher rate of nonlife threatening anastomotic complications than the HSA technique. Operative times are significantly longer for HSA, but length of hospital stay (LOS) and long-term weight loss are equivalent.

Esophagogastric junction distensibility is greater following Toupet compared to Nissen fundoplication.

BackgroundThe goal of antireflux surgery is to create a competent antireflux valve at the esophagogastric junction (EGJ). The two most common types of fundoplications constructed are the 360° Nissen and the 270° Toupet. We sought to determine whether there was a significant difference in distensibility at the EGJ based on fundoplication geometry (full vs. partial).MethodsThis is a retrospective review of prospective data. All subjects underwent laparoscopic fundoplication over a 47-month period for primary GERD or failed fundoplication. An endoluminal functional luminal-imaging probe (EndoFLIP®) was used to assess EGJ distensibility intraoperatively. Minimum esophageal diameter (Dmin), cross-sectional area (CSA), and distensibility index (DI) were measured at 30- and 40-mL balloon distension volumes prior to abdominal insufflation, after hiatal dissection, and following fundoplication. DI is defined as the narrowest CSA divided by the corresponding pressure expressed in mm2/mmHg. Analysis was conducted to compare distensibility metrics based on the type of fundoplication constructed (Nissen or Toupet). As a secondary outcome, we sought to determine whether there was a difference in distensibility of the EGJ prior to surgery in patients with primary GERD as opposed to those with recurrent GERD after a failed fundoplication.ResultsA total of 75 patients underwent fundoplications during the study interval. There were 44 primary and 31 reoperative fundoplications. Nissen fundoplication was constructed in 45 and Toupet in 30. Based on the distensibility index, the EGJ distensibility significantly decreased from prior to surgery to following fundoplication in all patients. Patients undergoing reoperative antireflux surgery had an initial DI at the EGJ similar to that of patients with primary GERD. Following Toupet, the EGJ was significantly more distensible than that after Nissen fundoplication.ConclusionsLaparoscopic fundoplication results in decreased EGJ distensibility in patients with GERD. The EGJ following partial fundoplication is significantly more distensible than that after a full fundoplication.

Picking apart surgical pick lists – Reducing variation to decrease surgical costs

BACKGROUND Average costs associated with common procedures can vary by surgeon without a corresponding variation in outcome or case complexity. METHODS De-identified cost and equipment utilization data were collected from our hospital for elective laparoscopic cholecystectomy performed by 17 different surgeons over a 6-month period. A group of surgeons used this data to design a standardized equipment pick list that became optional (not mandated) for laparoscopic cholecystectomy. Cost and consumable surgical supply utilization data were collected for six months prior to and following the creation of the standardized pick-list. RESULTS 280 elective laparoscopic cholecystectomies were performed during the study interval. In the 6 months after standardized pick list creation, the cost of disposable supplies utilized per case decreased by 32%. CONCLUSIONS Surgical cost savings can be achieved with standardized procedure pick lists and attention to the cost of consumable surgical supplies.

Per-Oral Endoscopic Myotomy (POEM) After Previous Laparoscopic Heller Myotomy Is Feasible and Safe in a Porcine Model.

Purpose: We sought to evaluate the feasibility, safety, and difficulty of performing the per-oral endoscopic myotomy (POEM) procedure in the setting of a prior Heller myotomy using a survival porcine model. Methods: Four pigs underwent laparoscopic Heller myotomy with Dor partial anterior fundoplication followed by the POEM performed 4 weeks later. Two additional pigs served as controls, undergoing only the POEM. Results: All procedures were completed without complications. The revisional POEM was not significantly more difficult than POEM controls based on procedure time, POEM procedure components, or procedure difficulty scores. Revisional POEM had a longer mean operative time when compared with Heller myotomy (126.0 vs. 83.8 min; P<0.01) but had a lower total difficulty score (28.6 vs. 52.1; P≪0.01). Conclusions: A POEM after previous Heller myotomy is safe and feasible in the porcine model and has potential as an option for patients suffering from recurrent or persistent symptoms after failed surgical myotomy.

Local Synthesis of Pepsin in Barrett’s Esophagus and the Role of Pepsin in Esophageal Adenocarcinoma

Objective: Despite widespread use of proton pump inhibitors (PPIs), the incidence of esophageal adenocarcinoma (EAC) continues to rise. PPIs reduce reflux acidity, but only transiently inactivate gastric enzymes. Nonacid reflux, specifically nonacid pepsin, contributes to carcinogenesis in the larynx. Given the carcinogenic potential of pepsin and inefficacy of PPIs to prevent EAC, the presence and effect of pepsin in the esophagus should be investigated. Methods: Normal and Barrett’s biopsies from 8 Barrett’s esophagus patients were collected for pepsin analysis via Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR). Human esophageal cells cultured from healthy patients were treated with pepsin (0.01-1 mg/mL; 1-20 hours), acid (pH 4) ± pepsin (5 minutes); real-time RT-PCR, ELISA, and cell migration were assayed. Results: Pepsin was detected in all 8 Barrett’s and 4 of 8 adjacent normal specimens. Pepsinogen mRNA was observed in 22 Barrett’s, but not in normal adjacent samples. Pepsin induced PTSG2 (COX-2) and IL-1β expression and cell migration in vitro. Conclusions: Pepsin is synthesized by metaplastic, Barrett’s esophageal mucosa. Nonacid pepsin increases metrics of tumorigenicity in esophageal epithelial cells in vitro. These findings implicate refluxed and locally synthesized pepsin in development and progression of EAC and, in part, explain the inefficacy of PPIs in the prevention of EAC.

Robotic skills can be aided by laparoscopic training

BackgroundGeneral Surgery is currently the fastest growing specialty with regards to robotic surgical system utilization. Contrary to the experience in laparoscopy, simulator training for robotic surgery is not widely employed partly because robotic surgical simulators are expensive. We sought to determine the effect of a robotic simulation curriculum and whether robotic surgical skills could be derived from those psychomotor skills attained in laparoscopic training.MethodsTwenty-seven trainees with no prior robotic experience and limited laparoscopy exposure were randomly assigned to one of three training groups: no simulator training, training on a fundamentals of laparoscopic surgery (FLS™) standard box trainer, and training on a robotic computer based simulator (da Vinci Skills Simulator™). Baseline robotic surgical skills were assessed on the clinical robot docked to a standard FLS trainer box on two tasks—intracorporeal knot tying and peg transfer. Subjects subsequently underwent four 1-h long training sessions in their assigned training environment over a course of several weeks. Robotic surgical skills were reassessed on the robot on the same two tasks used to assess skills prior to training.ResultsFLS training resulted in a greater score improvement than no training for both knot and peg scores. FLS training was also determined to result in greater score improvement than robotic simulator training for knot tying. There was no significant difference in peg transfer or knot tying scores when comparing robotic simulator training and no training.ConclusionsRobotic surgical skills can be in part derived from psychomotor skills developed in a laparoscopic trainer, especially for complex skills such as intracorporeal knot tying. Acquisition of robotic surgical skills may be enhanced by practice on a laparoscopic simulator using the FLS curriculum. This may be especially helpful when a robotic simulator is not available or is poorly accessible.

Intraoperative Assessment of Esophagogastric Junction Distensibility During Laparoscopic Heller Myotomy.

We sought to characterize the changes in esophagogastric junction (EGJ) distensibility during Heller Myotomy with Dor fundoplication using the EndoFLIP device. Intraoperative distensibility measurements on 14 patients undergoing Heller myotomy with Dor fundoplication were conducted over an 18-month period. Minimum esophageal diameter, cross-sectional areas, and distensibility index were measured at 30 and 40 mL catheter volumes before myotomy, postmyotomy, and following Dor fundoplication. Distensibility index is defined as the narrowest cross-sectional area divided by the corresponding pressure expressed in mm2/mm Hg. Heller myotomy was found to lead to significant changes in the distensibility characteristics of the EGJ. Minimum esophageal diameter and EGJ distensibility increased significantly with Heller myotomy.