MicroRNA-146a deficiency enhances host protection against murine cytomegalovirus.

Natural killer (NK) cells are innate lymphoid cells that protect a host from viral infections and malignancies. MicroRNA-146a (miR-146a) is an important regulator of immune function that is highly expressed in NK cells and is further upregulated during murine cytomegalovirus (MCMV) infection. Here we utilized mice with a global targeted deletion of miR-146a to understand its impact on the innate immune responses to MCMV infection. MiR-146a-/- mice were protected from lethal MCMV infection, which was intrinsic to the hematopoietic compartment based on bone marrow chimera experiments. NK cell depletion abrogated this protection, implicating NK cells as critical for the miR-146a-/- protection from MCMV. Surprisingly, NK cells from miR-146a-deficient mice were largely similar to control NK cells with respect to development, maturation, trafficking, and effector functions. However, miR-146a-/- mice had increased NK cell numbers and frequency of the most mature Stage IV (CD27-CD11b+) NK cells in the liver at baseline, enhanced STAT1 phosphorylation, and increased selective expansion of Ly49H+ NK cells and T cells during MCMV infection. This study demonstrates a critical role for miR-146a in the host response to MCMV, arising from mechanisms that include increased NK cell numbers and early T-cell expansion.

Effect of an opioid-free anesthetic on postoperative opioid consumption after laparoscopic bariatric surgery: a prospective, single-blinded, randomized controlled trial.

INTRODUCTION: Opioid administration has the benefit of providing perioperative analgesia but is also associated with adverse effects. Opioid-free anesthesia (OFA) may reduce postoperative opioid consumption and adverse effects after laparoscopic bariatric surgery. In this randomized controlled study, we hypothesized that an opioid-free anesthetic using lidocaine, ketamine, and dexmedetomidine would result in a clinically significant reduction in 24-hour postoperative opioid consumption when compared with an opioid-inclusive technique. METHODS: Subjects presenting for laparoscopic or robotic bariatric surgery were randomized in a 1:1 ratio to receive either standard opioid-inclusive anesthesia (group A: control) or OFA (group B: OFA). The primary outcome was opioid consumption in the first 24 hours postoperatively in oral morphine equivalents (OMEs). Secondary outcomes included postoperative pain scores, patient-reported incidence of opioid-related adverse effects, hospital length of stay, patient satisfaction, and ongoing opioid use at 1 and 3 months after hospital discharge. RESULTS: 181 subjects, 86 from the control group and 95 from the OFA group, completed the study per protocol. Analysis of the primary outcome showed no significant difference in total opioid consumption at 24 hours between the two treatment groups (control: 52 OMEs vs OFA: 55 OMEs, p=0.49). No secondary outcomes showed statistically significant differences between groups. CONCLUSIONS: This study demonstrates that an OFA protocol using dexmedetomidine, ketamine, and lidocaine for laparoscopic or robotic bariatric surgery was not associated with a reduction in 24-hour postoperative opioid consumption when compared with an opioid-inclusive technique using fentanyl.

Memory-like Differentiation, Tumor-Targeting mAbs, and Chimeric Antigen Receptors Enhance Natural Killer Cell Responses to Head and Neck Cancer.

PURPOSE: Head and neck squamous cell carcinoma (HNSCC) is an aggressive tumor with low response rates to frontline PD-1 blockade. Natural killer (NK) cells are a promising cellular therapy for T cell therapy-refractory cancers, but are frequently dysfunctional in patients with HNSCC. Strategies are needed to enhance NK cell responses against HNSCC. We hypothesized that memory-like (ML) NK cell differentiation, tumor targeting with cetuximab, and engineering with an anti-EphA2 (Erythropoietin-producing hepatocellular receptor A2) chimeric antigen receptor (CAR) enhance NK cell responses against HNSCC. EXPERIMENTAL DESIGN: We generated ML NK and conventional (c)NK cells from healthy donors, then evaluated their ability to produce IFNγ, TNF, degranulate, and kill HNSCC cell lines and primary HNSCC cells, alone or in combination with cetuximab, in vitro and in vivo using xenograft models. ML and cNK cells were engineered to express anti-EphA2 CAR-CD8A-41BB-CD3z, and functional responses were assessed in vitro against HNSCC cell lines and primary HNSCC tumor cells. RESULTS: Human ML NK cells displayed enhanced IFNγ and TNF production and both short- and long-term killing of HNSCC cell lines and primary targets, compared with cNK cells. These enhanced responses were further improved by cetuximab. Compared with controls, ML NK cells expressing anti-EphA2 CAR had increased IFNγ and cytotoxicity in response to EphA2+ cell lines and primary HNSCC targets. CONCLUSIONS: These preclinical findings demonstrate that ML differentiation alone or coupled with either cetuximab-directed targeting or EphA2 CAR engineering were effective against HNSCCs and provide the rationale for investigating these combination approaches in early phase clinical trials for patients with HNSCC.

Implementation of a structured robotic colorectal curriculum for general surgery residents.

There is increasing demand for colorectal robotic training for general surgery residents. We implemented a robotic colorectal surgery curriculum expecting that it would increase resident exposure to the robotic platform and would increase the number of graduating general surgery residents obtaining a robotic equivalency certificate. The aim of this study is to describe the components of the curriculum and characterize the immediate impact of the implementation or residents. Our curriculum started in 2019 and consists of didactics, simulation, and clinical performance. Objectives are specified for both junior residents (post-graduate years [PGY]1-2) and senior residents (PGY3-5). The robotic colorectal surgical experience was characterized by comparing robotic to non-robotic operations, differences in robotic operations across post-graduate year, and percentage of graduates achieving an equivalency certificate. Robotic operations are tracked using case log annotation. From 2017 to 2021, 25 residents logged 681 major operations on the colorectal service (PGY1 mean = 7.6 ± 4.6, PGY4 mean = 29.7 ± 14.4, PGY5 mean = 29.8 ± 14.8). Robotic colorectal operations made up 24% of PGY1 (49% laparoscopic, 27% open), 35% of PGY4 (35% laparoscopic, 29% open), and 41% of PGY5 (44% laparoscopic, 15% open) major colorectal operations. Robotic bedside experience is primarily during PGY1 (PGY1 mean 2.0 ± 2.0 bedside operations vs 1.4 ± 1.6 and 0.2 ± 0.4 for PGY4 and 5, respectively). Most PGY4 and 5 robotic experience is on the console (PGY4 mean 9.1 ± 7.7 console operations, PGY5 mean 12.0 ± 4.8 console operations). Rates of robotic certification for graduating chief residents increased from 0% for E-2013 to 100% for E-2018. Our robotic colorectal curriculum for general surgery residents has facilitated earlier and increased robotic exposure for residents and increased robotic certification for our graduates.

T-BET and EOMES sustain mature human NK cell identity and antitumor function.

Since the T-box transcription factors (TFs) T-BET and EOMES are necessary for initiation of NK cell development, their ongoing requirement for mature NK cell homeostasis, function, and molecular programming remains unclear. To address this, T-BET and EOMES were deleted in unexpanded primary human NK cells using CRISPR/Cas9. Deleting these TFs compromised in vivo antitumor response of human NK cells. Mechanistically, T-BET and EOMES were required for normal NK cell proliferation and persistence in vivo. NK cells lacking T-BET and EOMES also exhibited defective responses to cytokine stimulation. Single-cell RNA-Seq revealed a specific T-box transcriptional program in human NK cells, which was rapidly lost following T-BET and EOMES deletion. Further, T-BET- and EOMES-deleted CD56bright NK cells acquired an innate lymphoid cell precursor-like (ILCP-like) profile with increased expression of the ILC-3-associated TFs RORC and AHR, revealing a role for T-box TFs in maintaining mature NK cell phenotypes and an unexpected role of suppressing alternative ILC lineages. Our study reveals the critical importance of sustained EOMES and T-BET expression to orchestrate mature NK cell function and identity.

Endoscopic removal of eroded laparoscopic adjustable gastric bands: a preferred approach.

BACKGROUND: Complications related to laparoscopic adjustable gastric banding (LAGB) have led to an increased number of removals. An uncommon but potentially devastating complication is gastric band erosion into the gastric lumen, which can be managed by open surgical, laparoscopic, and endoscopic approaches. OBJECTIVE: A wide array of management techniques has been reported for removal of LAGB that have eroded into the stomach. We describe the preferred method for successful endoscopic band removal at our institution. SETTING: Community tertiary-care referral hospital accredited by the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program. METHODS: A single-center, retrospective review of a prospectively maintained database was used to identify patients who underwent LAGB removal from 2009 to 2019. We identified the subset of patients with band erosion. We analyzed patient characteristics, presenting symptoms, diagnostic modalities, and method of band extraction. RESULTS: A total of 132 patients underwent LAGB removal, among whom 22 (16.7%) patients were diagnosed with erosion. Seven (32%) patients underwent laparoscopic removal, 14 (64%) patients underwent endoscopic removal, and 1 patient (4%) underwent combined laparoscopic and endoscopic approach. These latter patients had variable amounts of erosion and buckle visibility, but all underwent endoscopic retrieval. We found that using an endoscopic retrograde cholangiopancreatography guidewire with an endoscopic retrograde cholangiopancreatography mechanical lithotriptor for band transection and snare for retrieval have been effective. CONCLUSIONS: A standardized, multidisciplinary, and minimally invasive endoscopic approach for LAGB erosion has been found to be successful without the need for further surgical intervention and may be offered to patients upon discovery of erosion.

Underrepresented Minorities in General Surgery Residency: Analysis of Interviewed Applicants, Residents, and Core Teaching Faculty.

BACKGROUND: The Accreditation Council for Graduate Medical Education (ACGME) requires diversity in residency. The self-identified race/ethnicities of general surgery applicants, residents, and core teaching faculty were assessed to evaluate underrepresented minority (URM) representation in surgery residency programs and to determine the impact of URM faculty and residents on URM applicants' selection for interview or match. STUDY DESIGN: Data from the 2018 application cycle were collated for 10 general surgery programs. Applicants without a self-identified race/ethnicity were excluded. URMs were defined as those identifying as black/African American, Hispanic/Latino/of Spanish origin, and American Indian/Alaskan Native/Native Hawaiian/Pacific Islander-Samoan. Statistical analyses included chi-square tests and a multivariate model. RESULTS: Ten surgery residency programs received 9,143 applications from 3,067 unique applicants. Applications from white, Asian, Hispanic/Latino, black/African American, and American Indian applicants constituted 66%, 19%, 8%, 7% and 1%, respectively, of those applications selected to interview and 66%, 13%, 11%, 8%, and 2%, respectively, of applications resulting in a match. Among programs' 272 core faculty and 318 current residents, 10% and 21%, respectively, were identified as URMs. As faculty diversity increased, there was no difference in selection to interview for URM (odds ratio [OR] 0.83; 95% CI 0.54 to 1.28, per 10% increase in faculty diversity) or non-URM applicants (OR 0.68; 95% CI 0.57 to 0.81). Similarly, greater URM representation among current residents did not affect the likelihood of being selected for an interview for URM (OR 1.20; 95%CI 0.90 to 1.61) vs non-URM applicants (OR 1.28; 95% CI 1.13 to 1.45). Current resident and faculty URM representation was correlated (r = 0.8; p = 0.005). CONCLUSIONS: Programs with a greater proportion of URM core faculty or residents did not select a greater proportion of URM applicants for interview. However, core faculty and resident racial diversity were correlated. Recruitment of racially/ethnically diverse trainees and faculty will require ongoing analysis to develop effective recruitment strategies.

Underrepresented Minorities are Underrepresented Among General Surgery Applicants Selected to Interview.

OBJECTIVE: Diversity is an ill-defined entity in general surgery training. The Accreditation Council for Graduate Medical Education recently proposed new common program requirements including verbiage requiring diversity in residency. "Recruiting" for diversity can be challenging within the constraints of geographic preference, type of program, and applicant qualifications. In addition, the Match process adds further uncertainty. We sought to study the self-identified racial/ethnic distribution of general surgery applicants to better ascertain the characteristics of underrepresented minorities (URM) within the general surgery applicant pool. DESIGN: Program-specific data from the Electronic Residency Application Service was collated for the 2018 medical student application cycle. Data were abstracted for all participating programs' applicants and those selected to interview. Applicants who did not enter a self-identified race/ethnicity were excluded from analysis. URM were defined as those identifying as Black/African American, Hispanic/Latino/of Spanish origin, American Indian/Alaskan Native, or Native Hawaiian/Pacific Islander-Samoan. Appropriate statistical analyses were accomplished. SETTING: Ten general surgery residency programs-5 independent programs and 5 university programs. PARTICIPANTS: Residency applicants to the participating general surgery residency programs. RESULTS: Ten surgery residency programs received 10,312 applications from 3192 unique applicants. Seven hundred and seventy-eight applications did not include a self-identified race/ethnicity and were excluded from analysis. The racial/ethnic makeup of applicants in this study cohort was similar to that from 2017 to 2018 Electronic Residency Application Service data of 4262 total applicants to categorical general surgery. Programs received a median of 1085 (range: 485-1264) applications each and altogether selected 617 unique applicants for interviews. Overall, 2148 applicants graduated from US medical schools, and of those, 595 (28%) were offered interviews. The mean age of applicants was 28.8 ± 3.8 years and 1316 (41%) were female. Hispanic/Latino/of Spanish origin, Black, and American Indian/Alaskan Native/Hawaiian/Pacific Islander-Samoan applicants constituted 12%, 8%, and 1% of total applicants, but only 8%, 6%, and 1% of those selected for interview. Overall, 29% of applicants had United States Medical Licensing Examination (USMLE) Step 1 scores ≤220; 37 (6%) of those selected for interviews had a USMLE Step 1 score of ≤220. A higher proportion of URM applicants had USMLE scores ≤220 compared to White and Asian applicants. Non-white self-identification was a significant independent predictor of a lower likelihood of interview selection. Female gender, USMLE Step 1 score >220, and graduating from a US medical school were associated with an increased likelihood of being selected to interview. CONCLUSIONS: URM applicants represented a disproportionately smaller percentage of applicants selected for interview. USMLE Step 1 scores were lower among the URM applicants. Training programs that use discreet USMLE cutoffs are likely excluding URM at a higher rate than their non-URM applicants. Attempts to recruit racially/ethnically diverse trainees should include program-level analysis to determine disparities and a focused strategy to interview applicants who might be overlooked by conventional screening tools.

The Program Evaluation Committee in Action: Lessons Learned From a General Surgery Residency's Experience.

OBJECTIVE: To evaluate the success of the annual program evaluation process and describe the experience of a Program Evaluation Committee for a General Surgery residency program. DESIGN: We conducted a retrospective review of the Program Evaluation Committee's meeting minutes, data inputs, and outcomes from 2014 to 2016. We identified top priorities by year, characterized supporting data, summarized the improvement plans and outcome measures, and evaluated whether the outcomes were achieved at 1 year. SETTING: Virginia Mason Medical Center General Surgery Residency Program. PARTICIPANTS: Program Evaluation Committee members including the Program Director, 2 Associate Program Directors, 2 Senior Faculty Members, and 1 Resident. RESULTS: All outcome measures were achieved or still in progress at 1 year. This included purchasing a GI mentor to improve endoscopic simulation training, establishing an outpatient surgery rotation to increase the volume of cases, and implementing a didactic course on adult learning principles for faculty development to improve intraoperative teaching. Primary reasons for slow progress were lack of follow-through by delegates or communication breakdown. CONCLUSIONS: The annual program evaluation process has been successful in identifying top priorities, developing action plans, and achieving outcome measures using our systematic evaluation process.

A Multicenter Prospective Comparison of the Accreditation Council for Graduate Medical Education Milestones: Clinical Competency Committee vs. Resident Self-Assessment.

OBJECTIVE: The Accreditation Council for Graduate Medical Education requires accredited residency programs to implement competency-based assessments of medical trainees based upon nationally established Milestones. Clinical competency committees (CCC) are required to prepare biannual reports using the Milestones and ensure reporting to the Accreditation Council for Graduate Medical Education. Previous research demonstrated a strong correlation between CCC and resident scores on the Milestones at 1 institution. We sought to evaluate a national sampling of general surgery residency programs and hypothesized that CCC and resident assessments are similar. DESIGN: Details regarding the makeup and process of each CCC were obtained. Major disparities were defined as an absolute mean difference of ≥0.5 on the 4-point scale. A negative assessment disparity indicated that the residents evaluated themselves at a lower level than did the CCC. Statistical analysis included Wilcoxon rank sum and Sign tests. SETTING: CCCs and categorical general surgery residents from 15 residency programs completed the Milestones document independently during the spring of 2016. RESULTS: Overall, 334 residents were included; 44 (13%) and 43 (13%) residents scored themselves ≥0.5 points higher and lower than the CCC, respectively. Female residents scored themselves a mean of 0.08 points lower, and male residents scored themselves a mean of 0.03 points higher than the CCC. Median assessment differences for postgraduate year (PGY) 1-5 were 0.03 (range: -0.94 to 1.28), -0.11 (range: -1.22 to 1.22), -0.08 (range: -1.28 to 0.81), 0.02 (range: -0.91 to 1.00), and -0.19 (range: -1.16 to 0.50), respectively. Residents in university vs. independent programs had higher rates of negative assessment differences in medical knowledge (15% vs. 6%; P = 0.015), patient care (17% vs. 5%; P = 0.002), professionalism (23% vs. 14%; P = 0.013), and system-based practice (18% vs. 9%; P = 0.031) competencies. Major assessment disparities by sex or PGY were similar among individual competencies. CONCLUSIONS: Surgery residents in this national cohort demonstrated self-awareness when compared to assessments by their respective CCCs. This was independent of program type, sex, or level of training. PGY 5 residents, female residents, and those from university programs consistently rated themselves lower than the CCC, but these were not major disparities and the significance of this is unclear.

Endothelial differentiation of diabetic adipose-derived stem cells.

BACKGROUND: Diabetic (DM) patients frequently lack autologous vascular tissue required for revascularization procedures and dialysis access creation. We have developed a tissue-engineered graft that uses adipose-derived stem cells (ASC) as endothelial cell substitutes. Here, we compare DM versus nondiabetic (NDM) ASC in terms of isolation efficiency, proliferation, commitment toward endothelial lineage, and seeding onto the luminal surface of a graft. METHODS: ASC were isolated from liposuction specimens of vascular surgery patients. Proliferation was assessed by constructing growth curves over 14 d. ASC were differentiated in endothelial growth medium (EGM2). Endothelial commitment was assessed by measuring endothelial cell-specific gene expression (CD31, von Willebrand factor) and by cord formation on Matrigel. Finally, ASC were seeded onto a vascular scaffold, flow conditioned, and imaged with confocal microscopy. RESULTS: Diabetes did not alter ASC isolation efficiency (224,028 ± 20,231 cells/g adipose for DM (n = 53) versus 259,345 ± 15,441 cells/g adipose for NDM (n = 145; P = 0.21). Growth curves for DM (n = 6) and NDM (n = 6) also appeared similar. After culture in EGM2, upregulation of CD31 and von Willebrand factor message was observed in NDM; these markers were found within the primary cultures of DM but no upregulation was observed after culture in EGM2. Both groups exhibited similar cord formation on Matrigel and retention to vascular scaffolds. CONCLUSIONS: Isolation and proliferation studies suggest that adipose is a promising source of stem cells for tissue engineering in the DM population. The angiogenic potential of DM ASC appears intact; however, differences in acquisition of endothelial cell markers suggest that differentiation may be inhibited or delayed by diabetes.

Laparoscopy-assisted versus balloon enteroscopy-assisted ERCP in bariatric post-Roux-en-Y gastric bypass patients.

BACKGROUND: Data on balloon enteroscopy-assisted ERCP (BEA-ERCP) versus laparoscopy-assisted ERCP (LA-ERCP) in post-Roux-en-Y gastric bypass (RYGB) patients are lacking. OBJECTIVES: To compare BEA-ERCP with LA-ERCP in post-RYGB patients and to identify factors that predict therapeutic success with BEA-ERCP. DESIGN: Retrospective chart review. SETTING: A single North American tertiary referral center. PATIENTS: The review included 56 bariatric post-RYGB patients who underwent ERCP. INTERVENTIONS: BEA-ERCP or LA-ERCP. MAIN OUTCOME MEASUREMENTS: Cannulation rate, therapeutic success, hospital stay, complications, procedure duration, endoscopist time, and cost. RESULTS: A total of 32 patients underwent BEA-ERCP, and 24 underwent LA-ERCP. LA-ERCP was superior to BEA-ERCP in papilla identification (100% vs 72%, P = .005), cannulation rate (100% vs 59%, P < .001), and therapeutic success (100% vs 59%, P < .001). The total procedure time was shorter (P < .001) and endoscopist time was longer (P = .006) for BEA-ERCP. There was no difference in postprocedure hospital stay (P = .127) or complication rate (P = .392) between the 2 groups. In the BEA-ERCP group, in patients having a Roux limb + biliopancreatic (from ligament of Treitz to jejunojejunal anastomosis), a limb length less than 150 cm was associated with therapeutic success. Starting with BEA-ERCP and continuing with LA-ERCP after a failed BEA-ERCP saved $1015 compared with starting with LA-ERCP. LIMITATIONS: Single center, retrospective study. CONCLUSIONS: In centers with expertise in deep enteroscopy and ERCP, post-RYGB patients with a Roux + ligament of Treitz to jejunojejunal anastomosis limb length less than 150 cm should first be offered deep enteroscopy-assisted ERCP. In patients with Roux + ligament of Treitz to jejunojejunal anastomosis (LTJJ) limb length 150 cm or longer, LA-ERCP should be the preferred approach because of the lack of need for a second procedure, equivalent morbidity and hospital stay, decreased endoscopist time, and decreased cost.

Laparoscopic resection of a gastric glomus tumor.

Surgeons are commonly asked to evaluate patients with subepithelial masses of the stomach. Glomus tumors are subepithelial mesenchymal tumors that are rarely included in the differential diagnosis when evaluating these patients. We present the case of 55-year old man with a gastric glomus tumor that was diagnosed preoperatively and removed by laparoscopic wedge resection. We review the preoperative evaluation and classic finding associated with this uncommon entity.

The role of diagnostic laparoscopy for acute abdominal conditions: an evidence-based review.

Diagnostic laparoscopy is minimally invasive surgery for the diagnosis of intraabdominal diseases. This study aim was a critical examination of the available literature on the role of laparoscopy for the diagnosis and treatment of acute intraabdominal conditions. A systematic literature search of English-language articles on MEDLINE, the Cochrane database of evidence-based reviews, and the Database of Abstracts of Reviews of Effects was performed for the period 1995-2006. The level of evidence in the identified articles was graded. This review examines the role of diagnostic laparoscopy for acute nonspecific abdominal pain, trauma, and the acute abdomen experienced by the critically ill patient. The indications, contraindications, risks, benefits, diagnostic accuracy of the procedure, and associated morbidity are discussed. The limitations of the available literature are highlighted, and evidence-based recommendations for the use of diagnostic laparoscopy to determine acute intraabdominal conditions are provided.

Reliable assessment of laparoscopic performance in the operating room using videotape analysis.

The Global Operative Assessment of Laparoscopic Skills (GOALS) is a valid assessment tool for objectively evaluating the technical performance of laparoscopic skills in surgery residents. We hypothesized that GOALS would reliably differentiate between an experienced (expert) and an inexperienced (novice) laparoscopic surgeon (construct validity) based on a blinded videotape review of a laparoscopic cholecystectomy procedure. Ten board-certified surgeons actively engaged in the practice and teaching of laparoscopy reviewed and evaluated the videotaped operative performance of one novice and one expert laparoscopic surgeon using GOALS. Each reviewer recorded a score for both the expert and the novice videotape reviews in each of the 5 domains in GOALS (depth perception, bimanual dexterity, efficiency, tissue handling, and overall competence). The scores for the expert and the novice were compared and statistically analyzed using single-factor analysis of variance (ANOVA). The expert scored significantly higher than the novice did in the domains of depth perception (p = .005), bimanual dexterity (p = .001), efficiency (p = .001), and overall competence ( p = .001). Interrater reliability for the reviewers of the novice tape was Cronbach alpha = .93 and the expert tape was Cronbach alpha = .87. There was no difference between the two for tissue handling. The Global Operative Assessment of Laparoscopic Skills is a valid, objective assessment tool for evaluating technical surgical performance when used to blindly evaluate an intraoperative videotape recording of a laparoscopic procedure.

Long-term outcome of esophagectomy for high-grade dysplasia or cancer found during surveillance for Barrett's esophagus.

Endoscopic surveillance is recommended for patients with Barrett's esophagus to detect high-grade dysplasia (HGD) or cancer. We studied the outcome of esophagectomy in a cohort of patients who developed HGD or cancer between 1995 and 2003 while under surveillance for Barrett's. Outcomes were measured by analysis of clinical records, symptom questionnaire, and SF-36 (version 2). In 34 patients, mean surveillance time was 48 months (range, 4-132); the mean number of endoscopies was 10 (range, 3-30). Preoperative diagnosis was HGD in 9 patients (26.5%), carcinoma in situ in 16 (47%), and adenocarcinoma in 9 (26.5%). There was no esophagectomy-related mortality; 10 patients (29%) had complications. At mean follow-up of 46 months (range, 13-108), SF-36 (version 2) results showed quality of life scores equal to or better than those of healthy individuals. Incidence and severity scores (VAS 1-10) for postoperative symptoms were reflux, 59% (2.8); dysphagia, 28% (3.7); bloating, 45% (2.6); nausea, 28% (2.1); and diarrhea, 55% (2.5). Twenty-nine patients (85%) have no clinical, radiographic, or endoscopic evidence of recurrent esophageal cancer or metastasis. One patient has metastatic disease. Endoscopic surveillance in Barrett's patients yields malignant lesions at an early, generally curable, stage. Esophagectomy is curative in the great majority and can be accomplished with minimal mortality and excellent quality of life.

Generalized approach for modeling minimally invasive surgery as a stochastic process using a discrete Markov model.

Minimally invasive surgery (MIS) involves a multidimensional series of tasks requiring a synthesis between visual information and the kinematics and dynamics of the surgical tools. Analysis of these sources of information is a key step in defining objective criteria for characterizing surgical performance. The Blue DRAGON is a new system for acquiring the kinematics and the dynamics of two endoscopic tools synchronized with the endoscopic view of the surgical scene. Modeling the process of MIS using a finite state model [Markov model (MM)] reveals the internal structure of the surgical task and is utilized as one of the key steps in objectively assessing surgical performance. The experimental protocol includes tying an intracorporeal knot in a MIS setup performed on an animal model (pig) by 30 surgeons at different levels of training including expert surgeons. An objective learning curve was defined based on measuring quantitative statistical distance (similarity) between MM of experts and MM of residents at different levels of training. The objective learning curve was similar to that of the subjective performance analysis. The MM proved to be a powerful and compact mathematical model for decomposing a complex task such as laparoscopic suturing. Systems like surgical robots or virtual reality simulators in which the kinematics and the dynamics of the surgical tool are inherently measured may benefit from incorporation of the proposed methodology.

Robotic versus conventional laparoscopic skill acquisition: implications for training.

BACKGROUND AND PURPOSE: Despite the growing interest in surgical robotics, very little study has been done regarding the acquisition of the skills needed to perform robotic surgery safely. The purpose of this study was to determine whether skills are transferred between conventional laparoscopy and robotically assisted surgery. SUBJECTS AND METHODS: Intracorporeal knot tying was used for evaluating laparoscopic skills for time and error performance. Twenty medical students without any laparoscopic experience were randomized into two groups. Group A initially performed knot tying with conventional laparoscopic instruments, were trained with the daVinci Robotic System, and then performed knot tying with conventional laparoscopy. Group B performed knot tying with robotics, trained with standard laparoscopy, and completed post-training knot tying with robotics. Pretraining and post-training tasks were videotaped and analyzed using a detailed scoring system by one independent referee, who was blinded to the subjects' experience. RESULTS: Pre-training knot tying was faster with robotics (4.4 v 9.9 minutes; P < 0.001). The mean composite scores were 27.4 for group A and 57.4 for group B (P = 0.09), and the error scores were 57.1 and 42.1 (P = 0.29), respectively. Post-training time for knot completion decreased to 6.7 minutes and 3.4 minutes for groups A and B, respectively. Composite scores increased significantly, from 27.4 to 66.1 for group A and 57.4 to 81.8 for group B. Error scores decreased to 32.9 for group A (P = 0.1) and 16.2 in group B (P = 0.02). CONCLUSIONS: There appears to be reciprocal transfer of skills between conventional laparoscopy and robotically assisted surgery. However, this transference is incomplete. Our results suggest that training with either technique or conventional laparoscopy is superior to training with robotics alone.