Trainee-associated outcomes in laparoscopic colectomy for cancer: propensity score analysis accounting for operative time, procedure complexity and patient comorbidity.

BACKGROUND: Surgical trainee association with operative outcomes is controversial. Studies are conflicting, possibly due to insufficient control of confounding variables such as operative time, case complexity, and heterogeneous patient populations. As operative complications worsen long-term outcomes in oncologic patients, understanding effect of trainee involvement during laparoscopic colectomy for cancer is of utmost importance. Here, we hypothesized that resident involvement was associated with worsened 30-day mortality and 30-day overall morbidity in this patient population. METHODS: Patients undergoing laparoscopic colectomy for oncologic diagnosis from 2005 to 2012 were assessed using the American College of Surgeons National Surgical Quality Improvement Program dataset. Propensity score matching accounted for demographics, comorbidities, case complexity, and operative time. Attending only cases were compared to junior, middle, chief resident, and fellow level cohorts to assess primary outcomes of 30-day mortality and 30-day overall morbidity. RESULTS: A total of 13,211 patients met inclusion criteria, with 4075 (30.8%) cases lacking trainee involvement and 9136 (69.2%) involving a trainee. Following propensity matching, junior (PGY 1-2) and middle level (PGY 3-4) resident involvement was not associated with worsened outcomes. Chief (PGY 5) resident involvement was associated with worsened 30-day overall morbidity (15.5 vs. 18.6%, p = 0.01). Fellow (PGY > 5) involvement was associated with worsened 30-day overall morbidity (16.0 vs. 21.0%, p < 0.001), serious morbidity (9.3 vs. 13.5%, p < 0.001), minor morbidity (9.8 vs. 13.1%, p = 0.002), and surgical site infection (7.9 vs. 10.5%, p = 0.006). No differences were seen in 30-day mortality for any resident level. CONCLUSION: Following propensity-matched analysis of cancer patients undergoing laparoscopic colectomy, chief residents, and fellows were associated with worsened operative outcomes compared to attending along cases, while junior and mid-level resident outcomes were no different. Further study is necessary to determine what effect the PGY surgical trainee level has on post-operative morbidity in cancer patients undergoing laparoscopic colectomy in the context of multiple collinear factors.

Comparative effectiveness of Roux-en-Y gastric bypass and sleeve gastrectomy in super obese patients.

BACKGROUND: The disproportionate increase in the super obese (SO) is a hidden component of the current obesity pandemic. Data on the safety and efficacy of bariatric procedures in this specific patient population are limited. Our aim is to assess the comparative effectiveness of the two most common bariatric procedures in the SO. METHODS: Using the Bariatric Outcomes Longitudinal Database from 2007 to 2012, we compared SO patients (BMI ≥ 50) undergoing laparoscopic Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Stepwise logistic regression modeling was used to calculate a propensity score to adjust for patient demographics and comorbidities. RESULTS: We identified 50,987 SO patients who underwent RYGB (N = 42,119) or SG (N = 8868). There was no difference in adjusted overall 30-day complication rate comparing RYGB and SG patients (11.5 vs. 11.1 %, p = 0.250). RYGB patients had higher adjusted rates of 30-day mortality (0.3 vs. 0.2 %, p = 0.042), reoperation (4.0 vs. 2.4 %, p < 0.001), and readmission (6.9 vs. 5.5 %, p < 0.001) compared to SG patients. The percent of total weight loss (%TWL) was significantly higher for RYGB patients compared to SG at 3 months (14.1 vs. 13.1 %, p < 0.001), 6 months (25.2 vs. 22.4 %, p < 0.001), and 12 months (34.5 vs. 29.7 %, p < 0.001). RYGB patients had increased resolution of all measured comorbidities: diabetes mellitus (61.6 vs. 50.8 %, p < 0.001), hypertension (43.1 vs. 34.5 %, p < 0.001), gastroesophageal reflux disease (53.9 vs. 32.5 %, p < 0.001), hyperlipidemia (39.7 vs. 32.5 %, p < 0.001), and obstructive sleep apnea (42.8 vs. 40.6 %, p = 0.058) at 12 months compared to SG patients. CONCLUSIONS: There are significant differences in comorbidity improvement and resolution as well as weight loss between RYGB and SG in the SO population. There was no difference in overall 30-day complications, but more RYGB patients required readmission and reoperation. However, RYGB was considerably more effective in controlling obesity-related comorbidities. Our results favor performance of RYGB in SO patients of appropriate risk.

Post-operative morbidity, but not mortality, is worsened by operative delay in septic diverticulitis.

PURPOSE: Optimal timing of surgery for acute diverticulitis remains unclear. A non-operative approach followed by elective surgery 6-week post-resolution is favored. However, a subset of patients fail on the non-operative management during index admission. Here, we examine patients requiring emergent operation to evaluate the effect of surgical delay on patient outcomes. METHODS: Patients undergoing emergent operative intervention for acute diverticulitis were queried using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2005 to 2012. Primary endpoints of 30-day overall morbidity and mortality were evaluated via univariate and multivariate analysis. RESULTS: Of the 2,119 patients identified for study inclusion, 57.2 % (n = 1212) underwent emergent operative intervention within 24 h, 26.3 % (n = 558) between days 1-3, 12.9 % (n = 273) between days 3-7, and 3.6 % (n = 76) greater than 7 days from admission. End colostomy was performed in 77.4 % (n = 1,640) of cases. Unadjusted age and presence of major comorbidities increased with operative delay. Further, unadjusted 30-day overall morbidity, mortality, septic complications, and post-operative length of stay increased significantly with operative delay. On multivariate analysis, operative delay was not associated with increased 30-day mortality but was associated with increased 30-day overall morbidity. CONCLUSIONS: Hartmann's procedure has remained the standard operation in emergent surgical management of acute diverticulitis. Delay in definitive surgical therapy greater than 24 h from admission is associated with higher rates of morbidity and protracted post-operative length of stay, but there is no increase in 30-day mortality. Prospective study is necessary to further answer the question of surgical timing in acute diverticulitis.

Surgical resident involvement differentially affects patient outcomes in laparoscopic and open colectomy for malignancy.

BACKGROUND: We evaluated effect of resident involvement on outcomes after laparoscopic and open colon resection for malignancy. METHODS: Patients undergoing colectomy were queried using the American College of Surgeons' National Surgical Quality Improvement Program. "Attending alone" and "Resident" cohorts were compared with primary end point of overall morbidity. RESULTS: Of 37,330 patients, residents were involved in 26,190 (70.2%) cases. Attending alone patients were older with higher vascular, cardiac, and pulmonary comorbidity. Univariate analysis demonstrated increased operative time (181.0 ± 98.4 vs 138.7 ± 77.0, P < .001), reoperation (5.7% vs 5.2%, P = .041), and readmission rates (11.9% vs 9.6%, P = .037) with resident involvement. Serious (16.0% vs 13.9%, P < .001), minor (17.5% vs 14.1%, P < .001), and overall morbidity (26.4% vs 22.5%, P < .001) were higher with resident participation. Mortality (2.0% vs 2.8%, P < .001) and failure to rescue (.8% vs 1.2%, P < .029) were lower with resident involvement. Resident involvement showed independent association with overall morbidity in both laparoscopic (odds ratio, 1.2; 95% confidence interval, 1.13 to 1.38, P < .001) and open cases (odds ratio 1.3, 95% confidence interval, 1.18 to 1.35, P < .001). CONCLUSIONS: Resident participation in colectomy for malignancy is associated with lower mortality at the expense of higher overall morbidity.

Delayed repair of obstructing ventral hernias is associated with higher mortality and morbidity.

BACKGROUND: Patients presenting with ventral hernia-related obstruction are commonly managed with emergent ventral hernia repair (VHR). Selected patients with resolution of obstruction may be managed in a delayed manner. This study sought to assess the effect of delay on VHR outcomes. METHODS: The American College of Surgeons' National Surgical Quality Improvement Program database from 2005 to 2011 was queried using diagnosis codes for ventral hernia with obstruction. Those who underwent repair over 24 hours after admission were classified as delayed repair. Preoperative comorbid conditions, American Society of Anesthesiology (ASA) scores, and 30-day outcomes were evaluated. RESULTS: We identified 16,881 patients with a mean age of 58 ± 15 years and body mass index of 36 ± 10. Delayed repair occurred in 27.7% of the patients. After controlling for comorbidities and ASA score, delayed VHR was independently associated with mortality (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.41 to 2.48, P < .001), morbidity (OR 1.4, 95% CI 1.24 to 1.50, P < .001), surgical site infection (OR 1.2, 95% CI 1.03 to 1.35, P = .016), and concurrent bowel resection (OR 1.2, 95% CI 1.03 to 1.34, P = .016). CONCLUSIONS: VHR for obstructed patients is frequently performed over 24 hours after admission. After adjusting for comorbid conditions and ASA score, delayed VHR is independently associated with worse outcomes. Prompt repair after appropriate resuscitation should be the management of choice.

Acute cholecystitis: risk factors for conversion to an open procedure.

BACKGROUND: Laparoscopic cholecystectomy is one of the most common general surgical procedures performed. Conversion to an open procedure (CTO) is associated with increased morbidity and length of stay. Patients presenting with acute cholecystitis are at higher risk for CTO. Studies have attempted to examine risk factors for CTO in patients who undergo laparoscopic cholecystectomy for acute cholecystitis but are limited by small sample size. The aim of this study was to identify preoperative variables that predict higher risk for CTO in patients presenting with acute cholecystitis. MATERIALS AND METHODS: Patients undergoing laparoscopic cholecystectomy for acute cholecystitis from 2005-2011 were identified from the American College of Surgeons' National Surgical Quality Improvement Program Participant Use File. Patients who underwent successful laparoscopic surgery were compared with those who required CTO. Demographics, comorbidities, and 30-d outcomes were analyzed. Multivariable logistic regression was used for variables with P value <0.1, with CTO used as the dependent variable. RESULTS: A total of 7242 patients underwent laparoscopic cholecystectomy for acute cholecystitis. CTO was reported in 436 patients (6.0%). Those who required conversion were older (60.7 ± 16.2 versus 51.6 ± 18.0, P = 0.0001) and mean body mass index was greater (30.8 ± 7.6 versus 30.0 ± 7.3, P = 0.033) compared with those whose procedure was completed laparoscopically. Vascular, cardiac, renal, pulmonary, neurologic, hepatic disease, diabetes, and bleeding disorders were more prevalent in CTO patients. Mortality (2.3% versus 0.7%, P < 0.0001), overall morbidity (21.8% versus 6.0%, P < 0.0001), serious morbidity (14.9% versus 3.8%, P < 0.0001), reoperation (3.4% versus 1.4%, P = 0.001), and surgical site infection (9.2% versus 1.8%, P < 0.0001) rates, as well as length of stay (8.6 ± 13.0 versus 3.4 ± 6.7, P < 0.0001) were greater in those requiring CTO. The following factors were independently associated with CTO: age (odds ratio [OR], 1.01, P = 0.015), male gender (OR, 1.77, P = 0.005), body mass index (OR, 1.04, P < 0.0001), preoperative alkaline phosphatase (OR, 1.01, P = 0.0005), white blood cell count (OR, 1.06, P = 0.0001), and albumin (OR, 0.52, P = 0.0001). CONCLUSIONS: CTO for acute cholecystitis remains low but not clinically negligible. The identified risk factors can potentially guide management and patient selection for delayed intervention for acute cholecystitis.

Obstructing ventral hernias are not independently associated with surgical site infections.

BACKGROUND: Delayed operative intervention in the setting of adhesive bowel obstruction has been recently shown to increase the rate of surgical site infection (SSI), raising the concern for bacterial translocation. The effect of obstruction on SSI rate in patients with ventral hernia is unknown. The aim of this study was to assess the association between bowel obstruction and SSI in patients undergoing ventral hernia repair (VHR). MATERIALS AND METHODS: This study is a retrospective database review. Patients undergoing isolated VHR from 2005-2011 were identified from the American College of Surgeons' National Surgical Quality Improvement Program database. Demographics, comorbidities, and 30-d outcomes were analyzed. Multivariate logistic regression was used for variables with a P value of <0.1. RESULTS: A total of 68,811 patients underwent isolated VHR; 53.1% were male with mean age of 53 ± 15 y and body mass index of 32 ± 8. Hernia-related obstruction was found in 17,058 (24.8%). In patients with obstruction, SSI was more frequent (3.2% versus 2.6%, P < 0.001). Obesity, advanced age, vascular, pulmonary, hepatic, renal disease, and diabetes were more prevalent. After controlling for confounding baseline variables, bowel obstruction was not independently associated with SSI (odds ratio, 0.983, 95% confidence interval, 0.872-1.107). Subgroup analysis of clean classified cases also demonstrated the lack of independent association between obstruction and SSI. CONCLUSIONS: Obstruction in patients undergoing VHR is not independently associated with SSI. Our results suggest that mesh implantation remains a viable option in this setting. Other confounding comorbid conditions should be assessed at the time of surgical intervention to identify patients appropriate for mesh repair.

Laparoscopic complete mesocolic excision for right colon cancer.

Laparoscopic colectomy for colon cancer has become a standard of care, with a number of publications highlighting its safety, improved postoperative recovery, and excellent oncologic outcomes. Complete mesocolic excision, recently reemphasized, is associated with superior oncologic outcomes, although this has not been discussed for laparoscopic surgery. A laparoscopic approach was performed for right colon cancer using a four-trocar technique. The key steps demonstrated are identification and high division of the ileocolic pedicle, medial-to-lateral mobilization of the ascending colon preserving the posterior mesocolic fascia, identification and high division of the right branch of the middle colic artery, mobilization of the greater omentum and hepatic flexure, completion of lateral mobilization of the ascending colon from the retroperitoneum, and mobilization of the small bowel mesentery up to the duodenum. A prospective series of 52 consecutive patients with right colon cancer underwent laparoscopic complete mesocolic excision with high-vessel ligation. Four of the patients required laparoscopic en bloc extended resections for local invasion. The median operative time was 136 min (interquartile range [IQR], 105-167 min), and the median blood loss was 20 ml (IQR, 10-45 ml). The median hospital stay was 3 days (IQR, 3-5 days). All the patients had an R0 oncologic resection with median margins of 12 cm, and a median of 22 lymph nodes (IQR, 18-29 lymph nodes) was retrieved. The median follow-up period was 38 months (IQR, 23-54 months). Of 14 patients with tumor-positive lymph nodes, 2 experienced distant recurrence. There were no local recurrences, but four patients experienced metastatic disease at a median of 37 months (IQR, 22-46 months). The median overall survival time was 38 months (IQR, 23-54 months). The embedded didactic video demonstrates a straight laparoscopic complete mesocolic excision with high-vessel ligation for a patient who had a right colon cancer. Laparoscopic right complete mesocolic excision is a safe and effective procedure associated with excellent 3-year oncologic outcomes and accelerated postoperative recovery.

Identification of consensus-based quality end points for colorectal surgery.

BACKGROUND: Process and outcome measures for quality assessment of colorectal surgical care are poorly defined. OBJECTIVE: The aim of this study was to develop candidate end points for use in surgeon-specific registries designed for case reporting and quality improvement program development. DESIGN: The study design was based on modified Delphi-based development of consensus quality end points. SETTING: This study was undertaken by the American Society of Colon and Rectal Surgeons Executive Council, Quality Committee, and by the ColoRectal Education System Template Committee, American Board of Colon and Rectal Surgery. PATIENTS: No patients were included in this study. INTERVENTIONS: Six areas of colorectal surgery were defined by members of the American Society of Colon and Rectal Surgeons' Executive Council and the American Board of Colon and Rectal Surgery to cover areas of importance for colorectal surgeons. These included colectomy, rectal cancer, hemorrhoidectomy, anal fistula and abscess, colonoscopy, and rectal prolapse. Relevant American Society of Colon and Rectal Surgeons' committee members through a series of 4 panel discussions identified important demographic, process, and outcome measures in each of these 6 areas that might be suitable for the American College of Surgeons case log. Panel size was sequentially expanded from 8 members to 28 members to include all active committee members. Panelists contributed additional process and outcome measures for inclusion during each discussion. Modified Delphi methodology was used to generate consensus, and, after each panel discussion, members rated the relative importance of each end point from 1 (least important) to 4 (most important). MAIN OUTCOME MEASURES: The mean rating for each process and outcome measure after each round was recorded with the use of standardized definitions for relevant variables. RESULTS: Eighty-nine process and outcome measures were compiled and rated. Mean scores following the final round ranged from a low of 1.3 (anal fistula/abscess, preoperative imaging) to a high of 4.0 (colectomy-anastomotic leak). LIMITATIONS: The limitations of this study involved the use of consensus, small study size, and the fact that no end points were excluded. CONCLUSIONS: With the use of modified Delphi methodology, a consensus-derived ranked list of 89 process and outcome measures was developed in 6 key areas of colorectal surgery. These data provide a framework for development of guideline standards for case-reporting program development initiatives for colon and rectal surgery.

Correlation of cerebral oximetry with internal carotid artery stump pressures in carotid endarterectomy.

OBJECTIVE: This study compares internal carotid artery (ICA) mean stump pressures (SPs) with cerebral oximetry monitoring during carotid endarterectomy (CEA). METHODS: A total of 104 consecutive patients undergoing CEA under general anesthesia (GA) during a 10-month period were prospectively evaluated. Baseline and postcarotid clamp regional cerebral oxygen saturation (rSO(2)) and mean ICA SPs were measured. Demographic, surgical, and medical variables were recorded for each case. RESULTS: There were no postoperative strokes. Thirteen patients were excluded because of incomplete data. Of the 40 patients who had <10% drop in rSO(2), 6 had SP <40 mm Hg. Regional cerebral oxygen saturation with a 15% saturation drop threshold was 76.3% sensitive and 81.1% specific in detecting patients with SP <40 mm Hg. With a threshold of 20% drop, sensitivity and specificity were 57.9% and 86.8%, respectively. CONCLUSIONS: Relative drop in rSO( 2) is neither sensitive nor specific in detecting patients with mean SP <40 mm Hg. These data do not support the use of cerebral oximetry as the sole monitoring modality during carotid endarterectomy under GA.

Parameterized computational imaging: Data driven computational modeling for image extension.

Parameterized Computational Imaging (PCI) allows for a continuous, portable and remote imaging of physiology without the continuous need of complex imaging systems. The method trades complex imaging equipment for computing power and potentially wireless measured parameters. The PCI algorithm uses a baseline image along with computational models to calculate physically measurable parameters. As the physically measurable parameters change the computational model is iteratively run until computationally predicted parameters matches the measured values. Swarm optimization routines are implemented to accelerate the process of finding the new values. A gelatin model with circular object is presented to demonstrate the PCI algorithm's ability to locate the circular object from four voltage measurements.

Inverse computational feedback optimization imaging applied to time varying changes in a homogeneous structure.

The technique of inverse computational feedback optimization imaging allows for the imaging of varying tissue without the continuous need of a complex imaging systems such as an MRI or CT. Our method trades complex imaging equipment for computing power. The objective is to use a baseline scan from an imaging system along with finite element method computational software to calculate the physically measurable parameters (such as voltage or temperature). As the physically measurable parameters change the computational model is iteratively run until it matches the measured values. Optimization routines are implemented to accelerate the process of finding the new values. Presented is a computational model demonstrating how the inverse imaging technique would work with a simple homogeneous sample with a circular structure. It demonstrates the ability to locate an object with only a few point measurements. The presented computational model uses swarm optimization techniques to help find the object location from the measured data (which in this case is voltage).

Safety and efficacy of intravascular ultrasound-guided inferior vena cava filter in super obese bariatric patients.

BACKGROUND: The morbidly obese (body mass index >40 kg/m(2)) are at significant risk of postoperative venous thromboembolism (VTE). Pulmonary embolism is the leading cause of death after Roux-en-Y gastric bypass, approximating .5%. Because of the technical limitations with fluoroscopy and table weight limits, it has been our practice at our university-based bariatric center to offer intravascular ultrasound (IVUS)-guided inferior vena cava filter (IVCF) placement at Roux-en-Y gastric bypass to patients with a history of VTE, hypercoagulable state, or profound immobility. METHODS: The hospital and outpatient records of all 594 patients who underwent Roux-en-Y gastric bypass from January 1, 2004 to October 31, 2006 were reviewed. The patients who had undergone concurrent IVUS-guided IVCF placement were selected. The co-morbidities, outcomes, and complications were recorded. RESULTS: Of the 594 patients, 31 (mean body mass index 71.2 +/- 2.96 kg/m(2)) had undergone concurrent IVUS-guided IVCF placement. The indications included a history of VTE (n = 5), a known hypercoagulable state (n = 2), and profound immobility (n = 25). The technical success rate was 96.8%. One filter was malpositioned in the iliac vein. No catheter site complications occurred. A ventilation/perfusion scan and computed tomography scan each detected pulmonary embolism in 2 surviving patients within 2 months postoperatively. Two patients died, 1 on postoperative day 8 and 1 on postoperative day 15 (6.4%). The mean follow-up time was 262.8 +/- 37.3 days. Autopsy excluded VTE or IVCF-related issues as the cause of death in both patients. CONCLUSION: These results suggest the efficacy of IVUS-guided IVCF placement in preventing mortality from pulmonary embolism in high-risk bariatric patients. IVUS-guided IVCF placement can be safely performed with an excellent success rate in high-risk patients who would not otherwise be candidates for intervention because of the technical limitations of fluoroscopy.

Modeling the interaction of electric current and tissue: importance of accounting for time varying electric properties.

Time varying computer models of the interaction of electric current and tissue are very valuable in helping to understand the complexity of the human body and biological tissue. The electrical properties of tissue, permittivity and conductivity, are vital to accurately modeling the interaction of the human tissue with electric current. Past models have represented the electric properties of the tissue as constant or temperature dependent. This paper presents time dependent electric properties that change as a result of tissue damage, temperature, blood flow, blood vessels, and tissue property. Six models are compared to emphasize the importance of accounting for these different tissue properties in the computer model. In particular, incorporating the time varying nature of the electric properties of human tissue into the model leads to a significant increase in tissue damage. An important feature of the model is the feedback loop created between the electric properties, tissue damage, and temperature.

The use of intravascular ultrasound imaging to improve use of inferior vena cava filters in a high-risk bariatric population.

OBJECTIVE: Pulmonary embolism is the leading cause of death after gastric bypass procedures for obesity, approximating 0.5% to 4%. All bariatric patients, but especially the super-obese, which have a body mass index (BMI) >50 kg/m(2), are at significant risk for postoperative venous thromboembolism (VTE). Visualization and weight limitations of fluoroscopy tables exclude most bariatric and all super-obese patients from inferior vena cava (IVC) filter placement using fluoroscopy. Intravascular ultrasound (IVUS)-guided IVC filter placement is the only modality that allows these high-risk patients to have an IVC filter placed. METHODS: Hospital and outpatient records of the 494 patients who underwent gastric bypass procedures from January 1, 2004, to May 31, 2006, were reviewed. All patients who had concurrent IVC filter placement with the use of IVUS guidance were selected. Comorbidities, outcomes, and complications were recorded. RESULTS: We identified 27 patients with mean BMI of 70 +/- 3 kg/m(2); of these, 25 were super-obese (BMI >50 kg/m(2)). Procedures included five laparoscopic and 22 open gastric bypass operations. All patients underwent concurrent IVC filter placement using IVUS guidance. In addition to super-obesity, indications for IVC filter placement included history of VTE (n = 4), known hypercoagulable state (n = 2), and profound immobility (n = 21). Mean follow up was 293 +/- 40 days. Technical success rate was 96.3%. There were no catheter site complications. In one surviving patient, a nonfatal pulmonary embolism was detected by computed tomography 2 months postoperatively. Two patients died, and autopsy excluded VTE as the cause of death in both. CONCLUSION: This study suggests efficacy of IVUS-guided IVC filter placement in preventing mortality from pulmonary embolism in high-risk bariatric patients, including the super-obese. IVUS-guided IVC filter placement can be safely performed with an excellent success rate in all bariatric patients, including the super-obese, who otherwise would not be candidates for IVC filter placement due to the limitations imposed by their large body habitus.