Preoperative intervention for smoking cessation: A systematic review

BACKGROUND

Smoking is associated with increased postoperative complications. Pre-surgical smoking cessation remains a challenge. Our aim was to summarize pre-hospital smoking cessation interventions and impact on smoking cessation rates.

METHODS

Independent review of English language articles identified from systematic searches of MEDLINE, PubMed, PsycInfo, Embase, Web of Science, and Cumulative Index to Nursing & Allied Health Literature databases from 1998 to 2019 was performed (PROSPERO registration number CRD42021247927). Studies of adult patients enrolled in a pre-hospital smoking cessation intervention were included. Studies with historical controls or only self-reported outcomes were excluded.

RESULTS

Nine articles including 1762 patients were identified. Exhaled CO was used to confirm cessation. Six studies reported smoking status day of surgery. Interventions included NRT, hand-held technology, e-cigarettes, decision aids/counseling and medications. Four studies demonstrated a difference in smoking cessation rates. Ethics and study appraisal were assessed using ROB2.

CONCLUSIONS

Based on the variability of interventions, settings, and outcomes, best practice for successful pre-hospital smoking cessation in surgery clinics would benefit from ongoing investigation.

Just What the Doctor Ordered: Missed Ordering of Venous Thromboembolism Chemoprophylaxis Is Associated With Increased VTE Events in High-risk General Surgery Patients

OBJECTIVE

To define the impact of missed ordering of venous thromboembolism (VTE) chemoprophylaxis in high-risk general surgery populations.

BACKGROUND

The primary cause of preventable death in surgical patients is VTE. Although guidelines and validated risk calculators assist in dosing recommendations, there remains considerable variability in ordering and adherence to recommended dosing.

METHODS

All adult inpatients who underwent a general surgery procedure between 2016 and 2019 and were entered into Atrium Health National Surgical Quality Improvement Program registry were identified. Patients at high risk for VTE (2010 Caprini score ≥5) and without bleeding history and/or acute renal failure were included. Primary outcome was 30-day postoperative VTE. Electronic medical record identified compliance with "perfect" VTE chemoprophylaxis orders (pVTE): no missed orders and no inadequate dose ordering. Multivariable analysis examined association between pVTE and 30-day VTE events.

RESULTS

A total of 19,578 patients were identified of which 4252 were high-risk inpatients. Hospital compliance of pVTE was present in 32.4%. pVTE was associated with shorter postoperative length of stay and lower perioperative red blood cell transfusions. There was 50% reduced odds of 30-day VTE event with pVTE (odds ratio: 0.50; 95% CI, 0.30-0.80) and 55% reduction in VTE event/mortality (odds ratio: 0.45; 95% CI, 0.31-0.63). After controlling for relevant covariates, pVTE remained significantly associated with decreased odds of VTE event and VTE event/mortality.

CONCLUSIONS

pVTE ordering in high-risk general surgery patients was associated with 42% reduction in odds of postoperative 30-day VTE. Comprehending factors contributing to missed or suboptimal ordering and development of quality improvement strategies to reduce them are critical to improving outcomes.

What Mesh Should be Used in Hernia Repair?

Ventral hernia repair is one of the most frequently performed general surgery operations in the world, yet the treatment of clean-contaminated and contaminated cases remains controversial. Biologic mesh has been thought to resist infection, decrease chronic wound complications, and reduce the need for reoperation. Their use continues to be predominant in contaminated and dirty cases. This article is a comprehensive review of what mesh to choose in both clean and contaminated single-staged, open ventral hernia repair with further considerations of tissue incorporation characteristics, cost, safety profiles, complications, recurrence, and long-term outcomes.

Utilization of telemedicine to provide post-discharge care: A comparison of pre-pandemic vs. pandemic care

BACKGROUND

Due to the COVID-19 pandemic, post-discharge virtual visits transitioned from a novel intervention to standard practice. Our aim was to evaluate participation in and outcomes of virtual post-discharge visits in the early-pandemic timeframe.

METHODS

Pandemic cohort patients were compared to historical patients. Patient demographics, clinical information, and post-discharge 30-day hospital encounters were compared between groups.

RESULTS

The historical cohort included 563 patients and the pandemic cohort had 823 patients. There was no difference in 30-day hospital encounters between patients who completed a video vs. telephone visit in the pandemic cohort (3.8% vs. 7.6%, p = 0.11). There was a lower 30-day hospital encounter rate in pandemic video and telephone visits compared to similar historical sub-groups.

CONCLUSION

Expansion of virtual post-discharge visits to include all patients and telephone calls did not negatively impact rates of 30-day post-discharge hospital encounters. Offering telehealth options for post-discharge follow-up does not appear to have negative impact on healthcare utilization.

Impact of COVID-19 on common non-elective general surgery diagnoses

BACKGROUND

During the COVID-19 pandemic, public health and hospital policies were enacted to decrease virus transmission and increase hospital capacity. Our aim was to understand the association between COVID-19 positivity rates and patient presentation with EGS diagnoses during the COVID pandemic compared to historical controls.

METHODS

In this cohort study, we identified patients ≥ 18 years who presented to an urgent care, freestanding ED, or acute care hospital in a regional health system with selected EGS diagnoses during the pandemic (March 17, 2020 to February 17, 2021) and compared them to a pre-pandemic cohort (March 17, 2019 to February 17, 2020). Outcomes of interest were number of EGS-related visits per month, length of stay (LOS), 30-day mortality and 30-day readmission.

RESULTS

There were 7908 patients in the pre-pandemic and 6771 in the pandemic cohort. The most common diagnoses in both were diverticulitis (29.6%), small bowel obstruction (28.8%), and appendicitis (20.8%). The lowest relative volume of EGS patients was seen in the first two months of the pandemic period (29% and 40% decrease). A higher percentage of patients were managed at a freestanding ED (9.6% vs. 8.1%) and patients who were admitted were more likely to be managed at a smaller hospital during the pandemic. Rates of surgical intervention were not different. There was no difference in use of ICU, ventilator requirement, or LOS. Higher 30-day readmission and lower 30-day mortality were seen in the pandemic cohort.

CONCLUSIONS

In the setting of the COVID pandemic, there was a decrease in visits with EGS diagnoses. The increase in visits managed at freestanding ED may reflect resources dedicated to supporting outpatient non-operative management and lack of bed availability during COVID surges. There was no evidence of a rebound in EGS case volume or substantial increase in severity of disease after a surge declined.

Deconstructing the roadmap to surgical residency: a national survey of residents illuminates factors associated with recruitment success as well as applicants' needs and beliefs

Purpose

As applications increase and residency becomes more competitive, applicants and programs will be challenged by increased demands on recruitment, metric assessment, and rank determination. Studies have investigated program opinions; however, this survey sought to illuminate the process from an applicant's perspective.

Methods

An anonymous survey was distributed to past or current surgery residents nationwide using social media and program director emails. Regression analyses were performed to assess factors correlating with percentage of programs which offered the applicant an interview.

Results

There were 223 respondents who applied to an average of 61 programs (± 40) with 16 (± 11) interviews offered. Applicants believed that programs were most interested in (1) personality, (2) letter of recommendation (LOR) writers, and (3) medical school reputation. Top factors considered by applicants in ranking were resident culture, location, program reputation, and autonomy. Bivariate analysis found factors that decreased percent of interview invites to be Asian race, whereas factors that increased interview invites included age, year of match, surgery clerkship grade, medicine clerkship grade, AOA status, honor surgery rotation, gold humanism (GHHS) status, phone call for interview made, and step scores (all p < 0.05). AOA status, step scores, honor surgery rotation, year of match, and Asian race remained significant after multivariate analysis.

Conclusions

National surveys illuminate how applicants approach the application process and what programs and applicants appear to value. This information provides insight and guidance to candidates and programs as the process of matching becomes more challenging with surging application numbers, changes in testing parameters and virtual interviews.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44186-022-00070-9.

Laparoscopy is associated with decreased all-cause mortality in patients undergoing emergency general surgery procedures in a regional health system

BACKGROUND

The aim of this study was to evaluate the use of laparoscopic surgery for common emergency general surgery (EGS) procedures within an integrated Acute Care Surgery (ACS) network. We hypothesized that laparoscopy would be associated with improved outcomes.

METHODS

Our integrated health care system's EGS registry created from AAST EGS ICD-9 codes was queried from January 2013 to October 2015. Procedures were grouped as laparoscopic or open. Standard descriptive and univariate tests were performed, and a multivariable logistic regression controlling for open status, age, BMI, Charlson Comorbidity Index (CCI), trauma tier, and resuscitation diagnosis was performed. Laparoscopic procedures converted to open were identified and analyzed using concurrent procedure billing codes across episodes of care.

RESULTS

Of 60,604 EGS patients identified over the 33-month period, 7280 (12.0%) had an operation and 6914 (11.4%) included AAST-defined EGS procedures. There were 4813 (69.6%) surgeries performed laparoscopically. Patients undergoing a laparoscopic procedure tended to be younger (45.7 ± 18.0 years vs. 57.2 ± 17.6, p < 0.001) with similar BMI (29.7 ± 9.0 kg/m² vs. 28.8 ± 8.3, p < 0.001). Patients in the laparoscopic group had lower mean CCI score (1.6 ± 2.3 vs. 3.4 ± 3.2, p ≤ 0.0001). On multivariable analysis, open surgery had the highest association with inpatient mortality (OR 8.67, 4.23-17.75, p < 0.0001) and at all time points (30-, 90-day, 1-, 3-year). At all time points, conversion to open was found to be a statistically significant protective factor.

CONCLUSION

Use of laparoscopy in EGS is common and associated with a decreased risk of all-cause mortality at all time points compared to open procedures. Conversion to open was protective at all time points compared to open procedures.

View from the Patient Perspective: Mixed-Methods Analysis of Post-Discharge Virtual Visits in a Randomized Controlled Trial

BACKGROUND

Virtual visits (VVs) are being used increasingly to provide patient-centered care and have undergone rapid uptake during the COVID-19 pandemic. Our aim was to compare satisfaction and convenience of virtual post-discharge follow-up for surgical patients and qualitatively analyze free-text survey responses in a randomized controlled noninferiority trial. Patient satisfaction with VVs has not been evaluated previously in a randomized controlled trial and few mixed-methods analyses have been done to understand barriers and facilitators to post-discharge visits.

STUDY DESIGN

Patients undergoing laparoscopic appendectomy or cholecystectomy were randomized to VV or in-person visit (2:1). Surveys with 11 multiple-choice and 2 open-ended questions evaluated patient satisfaction and convenience. Univariate analysis compared responses to the multiple-choice questions and qualitative content analysis evaluated open-ended responses.

RESULTS

Of 442 enrolled patients, 289 completed their postoperative visit and were sent surveys (55% response rate). Patients were categorized as VV (n = 135), crossover (randomized to virtual but completed in-person; n = 53), and in-person visits (n = 101). Patient-reported satisfaction was similar, but convenience was higher for VV patients. Open-ended responses (72 VVs, 14 crossovers, and 41 in-person visits) were qualitatively analyzed. In all groups, patient experience was influenced by quality of care, efficiency, and convenience. Barriers were different for virtual and in-person appointments.

CONCLUSIONS

We found that quality of, and access to, care-whether in person or virtual-remained critical components of patient satisfaction. VVs address many barriers associated with in-person visits and were more convenient, but can present additional technological barriers.

Postdischarge Virtual Visits for Low-risk Surgeries: A Randomized Noninferiority Clinical Trial

Importance

Postdischarge video-based virtual visits are a growing aspect of surgical care and have dramatically increased in the setting of the coronavirus disease 2019 (COVID-19) pandemic.

Objective

To evaluate the outcomes of all-cause 30-day hospital encounter proportion among patients who have a postdischarge video-based virtual visit follow-up compared with in-person follow-up.

Design, Setting, and Participants

Randomized, active, controlled noninferiority trial in an urban setting, including patients from a small community hospital and a large, tertiary care hospital. Patients who underwent minimally invasive appendectomy or cholecystectomy by a group of surgeons who cover emergency general surgery at these 2 hospitals were included. Patients undergoing elective and nonelective procedures were included.

Interventions

Patients were randomized in a 2:1 fashion to video-based virtual visit or in-person visit.

Main Outcomes and Measures

The primary outcome is the percentage of patients with 30-day hospital encounter, and we hypothesized that there would not be a significant increase in the 30-day hospital encounter proportion for patients who receive video-based virtual postdischarge care compared with patients who receive standard (in-person) care. Hospital encounter includes emergency department visit, observation, or inpatient admission.

Results

A total of 1645 patients were screened; 289 patients were randomized to the virtual group and 143 to the in-person group. Fifty-three patients crossed over to the in-person follow-up group. The percentage of patients who had a hospital encounter was noninferior for virtual visits (12.8% vs 13.3% for in-person, Δ 0.5% with 1-sided 95% CI, -∞ to 5.2%). The amount of time patients spent with the clinician (mean of 8.4 minutes virtual vs 7.8 minutes in-person; P = .30) was not different, but the median overall postoperative visit time was 27.5 minutes shorter (95% CI, -33.5 to -24.0).

Conclusions and Relevance

Postdischarge video-based virtual visits did not increase hospital encounter proportions and provided shorter overall time commitment but equal time with the surgical team member. This information will help surgeons and patients feel more confident in using video-based virtual visits.

Trial Registration

ClinicalTrials.gov Identifier: NCT03258177.

Palliative Care in Emergency General Surgery Patients: Reduced Inpatient Mortality And Increased Discharge to Hospice

BACKGROUND

Admissions due to emergency general surgery (EGS) are on the rise, and patients who undergo emergency surgery are at increased risk of mortality. We hypothesized that utilization of palliative care and discharge to hospice in the EGS population have increased over time and that this is associated with a decrease in inpatient mortality.

METHODS

Using the 2002-2011 nationwide inpatient sample and American Association for the Surgery of Trauma-defined EGS diagnosis codes, we identified patients ≥18 years old with an EGS admission. Demographics, hospitalization characteristics, mortality, use of palliative care services, and discharge to hospice were queried. All Patient Refined-Diagnosis Related Group risk of mortality was used to categorize those with an extreme likelihood of dying (ELD). Multivariable logistic regression was used to investigate the association between palliative care consult and discharge to hospice.

RESULTS

Of the included patients, 0.3% received palliative care and 0.2% were discharged to hospice. Over time, rates of palliative care and hospice discharge increased while inpatient mortality decreased. In the 4% of patients with ELD, 3% received palliative care, 5% were transitioned to hospice care, and 22% suffered inpatient mortality. Controlling for patient characteristics, utilization of palliative care services was associated with increased odds of discharge to hospice compared to inpatient mortality (OR = 1.78 all patients and OR = 2.04 for ELD).

CONCLUSIONS

Despite the known increased risks associated with emergency surgical diagnoses, palliative care services remain infrequently utilized in the EGS population. This may be an opportunity for lessening suffering, improving patient-concordant care and outcomes, and reducing nonbeneficial and unwanted care.

Patient Factors Lead to Extensive Variation in Outcomes and Cost From Cholecystectomy

BACKGROUND

Cholecystectomy is a common procedure with significantly varied outcomes. We analyzed differences in comorbidities, outcomes, and cost of cholecystectomy by acute care surgery (ACS) versus hepatopancreaticobiliary (HPB) surgery.

STUDY DESIGN

Patients were retrospectively identified between 2008 and 2015. Exclusion criteria included the following: (1) part of another procedure; (2) abdominal trauma; (3) ICU admission; vasopressors.

RESULTS

One hundred and twenty-six ACS and 122 HPB patients were analyzed. The HPB subset had higher burden of comorbid disease and significantly lower projected 10-year survival (87.4% ACS vs 68.5% HPB, P < .0001). Median lengths of stay were longer in HPB patients (2 vs 5 days, P < .0001) as were readmission rates (30-day 5.6% vs 13.1%, P = .040; 90-day 7.9% vs 20.5%, P = .005). Median cost was higher including operative supply cost ($969.42 vs $1920.66, P < .0001) and total cost of care ($7340.66 vs $19 338.05, P < .0001). A predictive scoring system for difficult gallbladders was constructed and a phone application was created.

CONCLUSION

Cholecystectomy in a complicated patient can be difficult with longer hospital stays and higher costs. The utilization of procedure codes to explain disparities is not sufficient. Incorporation of comorbidities needs to be addressed for planning and reimbursement.

Non-elective paraesophageal hernia repair: surgical approaches and short-term outcomes

BACKGROUND

The majority of laparoscopic paraesophageal hernia (PEH) repairs are performed electively. We aimed to investigate the frequency of non-elective laparoscopic (MIS) PEH repair and compare 30-day outcomes to elective MIS repairs and non-elective open repairs. We hypothesized that an increasing percentage of non-elective PEH repairs would be performed laparoscopically and that this population would have improved outcomes compared to non-elective open PEH counterparts.

METHODS

The 2011-2016 NSQIP PUFs were used to identify patients who underwent PEH repair. Case status was classified as open vs. MIS and elective versus non-elective. Preoperative patient characteristics, operative details, discharge destination, and 30-day postoperative complication rates were compared. Logistic regression was used to examine the impact of case status on 30-day mortality.

RESULTS

We identified 20,010 patients who underwent PEH. There were an increasing number of MIS PEH repairs in NSQIP between 2011 and 2016. Non-elective repairs were performed in 2,173 patients and 73.4% of these were completed laparoscopically. Elective MIS patients were younger, had a higher BMI, and were more likely to be functionally independent (p < 0.01) than their non-elective counterparts. Non-elective MIS patients had a higher wound class and ASA class compared to their elective counterparts. Compared to elective MIS cases, non-elective MIS PEH repair was associated with increased odds of mortality, even after controlling for patient characteristics (OR = 1.76, p = 0.02). There was no statistically significant difference in mortality for non-elective MIS vs. non-elective open PEH repair. There is an increase in non-elective PEH repairs recorded in NSQIP over time studied.

CONCLUSIONS

The population undergoing non-elective MIS PEH repairs is different from their elective MIS counterparts and experience a higher postoperative mortality rate. While the observed increased utilization of MIS techniques in non-elective PEH repairs likely provides benefits for the patient, there remain differences in outcomes for these patients compared to elective PEH repairs.

SAGES primer for taking care of yourself during and after the COVID-19 crisis

COVID-19 is a pandemic which has affected almost every aspect of our life since starting globally in November 2019. Given the rapidity of spread and inadequate time to prepare for record numbers of sick patients, our surgical community faces an unforeseen challenge. SAGES is committed to the protection and care of patients, their surgeons and staff, and all who are served by the medical community at large. This includes physical health, mental health, and well-being of all involved. The fear of the unknown ahead can be paralyzing. International news media have chronicled the unthinkable situations that physicians and other health care providers have been thrust into as a result of the COVID-19 pandemic. These situations include making life or death decisions for patients and their families regarding use of limited health care resources. It includes caring for patients with quickly deteriorating conditions and limited treatments available. Until recently, these situations seemed far from home, and now they are in our own hospitals. As the pandemic broadened its reach, the reality that we as surgeons may be joining the front line is real. It may be happening to you now; it may be on the horizon in the coming weeks. In this context, SAGES put together this document addressing concerns on clinician stressors in these times of uncertainty. We chose to focus on the emotional toll of the situation on the clinician, protecting vulnerable persons, reckoning with social isolation, and promoting wellness during this crisis. At the same time, the last part of this document deals with the “light at the end of the tunnel,” discussing potential opportunities, lessons learned, and the positives that can come out of this crisis.

Maximizing the Calm before the Storm: Tiered Surgical Response Plan for Novel Coronavirus (COVID-19)

The novel coronavirus (COVID-19) was first diagnosed in Wuhan, China in December 2019 and has now spread throughout the world, being verified by the World Health Organization as a pandemic on March 11. This had led to the calling of a national emergency on March 13 in the US. Many hospitals, healthcare networks, and specifically, departments of surgery, are asking the same questions about how to cope and plan for surge capacity, personnel attrition, novel infrastructure utilization, and resource exhaustion. Herein, we present a tiered plan for surgical department planning based on incident command levels. This includes acute care surgeon deployment (given their critical care training and vertically integrated position in the hospital), recommended infrastructure and transfer utilization, triage principles, and faculty, resident, and advanced care practitioner deployment.

The next step in surgical quality improvement: outcome situational awareness

Summary

A similar theme unites proposed solutions for stagnant improvement in outcomes and rising health care costs: eliminate unnecessary variation in the care of surgical patients. While large quality-improvement projects like the Americal College of Surgeons National Surgical Quality Improvement Program have historically led to improved patient outcomes at the hospital level, the next step in surgical quality improvement is to eliminate unnecessary variation at the level of the individual surgeon. Critical examination of individualized clinical, financial and patient-reported outcomes — outcome situational awareness — along with peer group comparison will help surgeons to identify variation in patient care. We are piloting an interactive software platform at our institution to provide information on individualized clinical, financial and patient-reported outcomes in real time through automatic data population of a central REDCap database. These individualized data along with peer group comparison allow surgeons to objectively determine areas of potential improvement.

Modifying Interhospital Hepatopancreatobiliary Transfers Based on Predictive Analytics: Moving from a Center of Excellence to a Health-Care System of Excellence

Regionalization of complex surgical care has increased interhospital transfers to quaternary centers within large health-care systems. Risk-based patient selection is imperative to improve resource allocation without compromising care. This study aimed to develop predictive models for identifying low-risk patients for transfer to a fully integrated satellite hepatopancreatobiliary (HPB) service in the northeast region of the health-care system. HPB transfers to the quaternary center over 15 months from hospitals in proximity to the satellite HPB center. A predictive tool was developed based on simple pretransfer variables and outcomes for 30-day major complications (Clavien grade ≥ 3), readmission, and mortality. Thresholds for "low risk" were set at different SDs below mean for each model. Predictive models were developed from 51 eligible northeast region patient transfers for major complications (Brier score 0.1948, receiver operator characteristic (ROC) 0.7123, P = 0.0009), readmission (Brier score 0.0615, ROC 0.7368, P = 0.0020), and mortality (Brier score 0.0943, ROC 0.7989, P = 0.0023). Thresholds set from 2 SD below the mean for all models identified 2 as "low risk." Adjusting the threshold for the serious complication model to only 1 SD below the mean increased the "low-risk" cohort to five patients. These models demonstrate an easy-to-use tool to assist surgeons in identifying low-risk patients for diversion to a fully integrated satellite center. Improved interhospital transfers within a region could begin a transition from centers of excellence toward health-care systems of excellence.

Modifying Interhospital Hepatopancreatobiliary Transfers Based on Predictive Analytics: Moving from a Center of Excellence to a Health-Care System of Excellence

Regionalization of complex surgical care has increased interhospital transfers to quaternary centers within large health-care systems. Risk-based patient selection is imperative to improve resource allocation without compromising care. This study aimed to develop predictive models for identifying low-risk patients for transfer to a fully integrated satellite hepatopancreatobiliary (HPB) service in the northeast region of the health-care system. HPB transfers to the quaternary center over 15 months from hospitals in proximity to the satellite HPB center. A predictive tool was developed based on simple pretransfer variables and outcomes for 30-day major complications (Clavien grade ≥ 3), readmission, and mortality. Thresholds for “low risk” were set at different SDs below mean for each model. Predictive models were developed from 51 eligible northeast region patient transfers for major complications (Brier score 0.1948, receiver operator characteristic (ROC) 0.7123, P = 0.0009), readmission (Brier score 0.0615, ROC 0.7368, P = 0.0020), and mortality (Brier score 0.0943, ROC 0.7989, P = 0.0023). Thresholds set from 2 SD below the mean for all models identified 2 as “low risk.” Adjusting the threshold for the serious complication model to only 1 SD below the mean increased the “low-risk” cohort to five patients. These models demonstrate an easy-to-use tool to assist surgeons in identifying low-risk patients for diversion to a fully integrated satellite center. Improved interhospital transfers within a region could begin a transition from centers of excellence toward health-care systems of excellence.

Updates in Mesh and Biomaterials

Prior publications of the Surgical Clinics of North America have highlighted the technical challenges of abdominal wall reconstruction. This article provides an update on synthetic, biologic, and biosynthetic mesh research since the 2013 Surgical Clinics of North America hernia publication and highlights the future of mesh research. This update features research that has been conducted since the prior publication to guide surgeons to choose the best and most appropriate mesh for their patients.

Global Outreach Using a Systematic, Competency-Based Training Paradigm for Inguinal Hernioplasty

Importance

Sustainable, capacity-building educational collaborations are essential to address the global burden of surgical disease.

Objective

To assess an international, competency-based training paradigm for hernia surgery in underserved countries.

Design, Setting, and Participants

In this prospective, observational study performed from November 1, 2013, through October 31, 2015, at 16 hospitals in Brazil, Ecuador, Haiti, Paraguay, and the Dominican Republic, surgeons completed initial training programs in hernia repair, underwent interval proficiency assessments, and were appointed regional trainers. Competency-based evaluations of technical proficiency were performed using the Operative Performance Rating Scale (OPRS). Maintenance of proficiency was evaluated by video assessments 6 months after training. Certified trainees received incentives to document independent surgical outcomes after training.

Main Outcomes and Measures

An OPRS score of 3.0 (scale of 1 [poor] to 5 [excellent]) indicated proficiency. Secondary outcomes included initial vs final scores by country, scores among surgeons trained by the regional trainers (second-order trainees), interval scores 6 months after training, and postoperative complications.

Results

A total of 20 surgeon trainers, 81 local surgeons, and 364 patients (343 adult, 21 pediatric) participated in the study (mean [SD] age, 47.5 [16.3] years; age range, 16-83 years). All 81 surgeons successfully completed the program, and all 364 patients received successful operations. Mean (SD) OPRS scores improved from 4.06 (0.87) before the initial training program to 4.52 (0.57) after training (P < .001). No significant variation was found by country in final scores. On trainee certification, 20 became regional trainers. The mean (SD) OPRS score among 53 second-order trainees was 4.34 (0.68). After 6-month intervals, the mean (SD) OPRS score among participating surgeons was 4.34 (0.55). The overall operative complication rate during training series was 1.1%.

Conclusions and Relevance

Competency-based training helps address the global burden of surgical disease. The OPRS establishes an international standard of technical assessment. Additional studies of long-term surgeon trainer proficiency, community-specific quality initiatives, and expansion to other operations are warranted.

Acuity, outcomes, and trends in the transfer of surgical patients: a national study

INTRODUCTION

With the regionalization of surgical care, reduction in the rural workforce, rising healthcare costs, and increasing focus on surgical outcomes, appropriate transfer of surgical patients is an increasingly important aspect of health care. This study examines patients transferred for surgical intervention through a national sample.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2005 to 2012 for surgery patients who were transferred from an outside hospital or emergency department (ED) and compared patients undergoing surgery without transfer. Patients were divided into two time periods (TP): 2005-2008 (TP1) and 2008-2012 (TP2) for analysis; patient characteristics and top CPT codes for each TP were collected. Univariate analysis and matched cohorts were used to compare the groups.

RESULTS

Overall, 61,204 patients were transferred and underwent surgery. The rate of transferred surgery patients increased from 3.2% in TP1 to 4.5% in TP2 (p < 0.0001). Compared to non-transferred patients, transferred patients had higher rates of diabetes (23.4 vs. 17.6%, p < 0.0001), tobacco use (27.9 vs. 20.3%, p < 0.0001), Charlson comorbidity index (mean score 1.5 vs. 0.8, p < 0.0001), preoperative sepsis (32.0 vs. 9.4%, p < 0.0001), and need for emergent surgery (41.3 vs. 14.4%, p < 0.0001). From TP1 to TP2, there was an increase in transferred patients who were obese (33.9-36.4%, p < 0.0001) and had emergent transfers (39.6-41.8%, p < 0.0001), with a decrease in diabetic patients (24.7-23.1%, p < 0.0001). From TP1 to TP2, transferred patients had more minor complications (17.7-31.0%, p < 0.0001), but fewer major complications (32.1-23.9%, p < 0.0001) and lower 30-day mortality (11.8-8.1%, p < 0.0001).

CONCLUSIONS

Patients transferred for surgery represent a higher acuity population than non-transferred patients, and the number of transfers continues to rise. Even when matched by comorbidities, transferred patients have worse outcomes. Surgical sub-specialization and physician tiering may complicate future transfer practices. Efficient transfers, effective physician communication, and ready availability of medical records are critical in improving patient transfers.

National outcomes of laparoscopic Heller myotomy: operative complications and risk factors for adverse events

INTRODUCTION

Laparoscopic Heller myotomy (LHM) has supplanted an open approach due to decreased operative morbidity. Our goal was to quantify the incidence of peri-operative complications and identify risk factors for adverse outcomes in LHM.

METHODS

All LHM were queried from 2005 to 2011 from the National Surgical Quality Improvement Program database. Adverse outcomes were identified, and univariate and stepwise logistic regression (MVR) was then performed to quantify association.

RESULTS

There were 1,237 LHM in the study period. Patient averages were: age 51.9 ± 16.8 years, BMI 27.3 ± 6.6 kg/m(2), Charlson comorbidity index (CCI) 0.2 ± 0.6. 15.3 % had >10 % body mass loss in the preoperative 6 months. During surgery, 10.2 % underwent concomitant EGD, and mean operative time was 141.6 ± 63.4 min. There were 7(0.06 %) wound complications, 22(1.8 %) general complications, and 30(2.4 %) major complications. Average length of stay (LOS) was 2.8 ± 5.5 days. The rate of readmission and reoperation were 3.1 and 2.3 %, respectively, and there were 4(0.03 %) deaths. General and major complications were associated with alcohol use, pack-years of smoking, weight loss, history of stroke, radiation therapy, and longer operative times (p < 0.05); however, these factors did not remain significant on MVR (p > 0.05). Operative time was found to be significantly longer by 35.3 min for inpatients, 43.1 min in functionally dependent patients, 50.0 min in preoperative septic patients, and 17.2 min with concomitant EGD (p < 0.01 for all). LOS was found to be longer by 1.9 days for inpatients, 1.8 days in ASA category ≥3, and 1.2 days per one point increase in CCI (p < 0.001 for all).

CONCLUSION

LHM is being performed nationally with a low incidence of operative complications and mortality. General and major complications following LHM are associated with patient alcohol use, pack-years of smoking, weight loss, history of stroke, radiation therapy, and longer operative times. Additionally, independent predictors of longer operative time and LOS were identified.

The current status of biosynthetic mesh for ventral hernia repair

Although synthetic mesh has dramatically reduced recurrence in elective hernia repair, its use in contaminated surgical fields has been traditionally associated with complications such as wound sepsis, enterocutaneous fistulas, and chronic prosthetic infection. Biologic meshes emerged in the late 1990s with a rapid popularity fueled largely by the demand for an appropriate substitute in lieu of synthetic mesh in these complex cases; however, the high cost and rate of hernia recurrence have tempered the initial enthusiasm. Biosynthetic meshes were developed as a possible cost-effective alternative to both synthetic and tissue-derived products. Using biodegradable polymers instead of animal or cadaver tissue, they provide a temporary scaffold for deposition of proteins and cells necessary for tissue ingrowth, neovascularization, and host integration. Herein we review the current status of biosynthetic meshes for hernia repair.

Evaluation of absorbable mesh fixation devices at various deployment angles

BACKGROUND

Hernia repair failure may occur due to suboptimal mesh fixation by mechanical constructs before mesh integration. Construct design and acute penetration angle may alter mesh-tissue fixation strength. We compared acute fixation strengths of absorbable fixation devices at various deployment angles, directions of loading, and construct orientations.

METHODS

Porcine abdominal walls were sectioned. Constructs were deployed at 30°, 45°, 60°, and 90° angles to fix mesh to the tissue specimens. Lap-shear testing was performed in upward, downward, and lateral directions in relation to the abdominal wall cranial-caudal axis to evaluate fixation. Absorbatack™ (AT), SorbaFix™ (SF), and SecureStrap™ in vertical (SSV) and horizontal (SSH) orientations in relation to the abdominal wall cranial-caudal axis were tested. Ten tests were performed for each combination of device, angle, and loading direction. Failure types and strength data were recorded. ANOVA with Tukey-Kramer adjustments for multiple comparisons and χ (2) tests were performed as appropriate (p < 0.05 considered significant).

RESULTS

At 30°, SSH and SSV had greater fixation strengths (12.95, 12.98 N, respectively) than SF (5.70 N; p = 0.0057, p = 0.0053, respectively). At 45°, mean fixation strength of SSH was significantly greater than SF (18.14, 11.40 N; p = 0.0002). No differences in strength were identified at 60° or 90°. No differences in strength were noted between SSV and SSH with different directions of loading. No differences were noted between SS and AT at any angle. Immediate failure was associated with SF (p < 0.0001) and the 30° tacking angle (p < 0.01).

CONCLUSIONS

Mesh-tissue fixation was stronger at acute deployment angles with SS compared to SF constructs. The 30° angle and the SF device were associated with increased immediate failures. Varying construct and loading direction did not generate statistically significant differences in the fixation strength of absorbable fixation devices in this study.

Ventralight ST and SorbaFix versus Physiomesh and Securestrap in a porcine model

Ventralight ST with SorbaFix fixation exhibited more favorable strength of tissue ingrowth and histologic response with similar mesh contracture and adhesion characteristics compared with Physiomesh fixed with Securestrap.

Background and Objectives:

The objective of this study was to compare mesh contracture, adhesion characteristics, tissue ingrowth, and histologic response of Ventralight ST/SorbaFix (C.R. Bard/Davol, Warwick, RI, USA) with Physiomesh/Securestrap (Ethicon, Somerville, NJ, USA) in a porcine model of laparoscopic ventral hernia repair.

Methods:

Standard laparoscopic technique was used to bilaterally implant meshes in 10 female Yorkshire swine. Each animal received either two Ventralight ST meshes (oval shaped, 10.2 × 15.2 cm) or two Physiomesh meshes (oval shaped 10 × 15 cm), one on either side of the midline. The meshes were fixated to the intact peritoneum with either SorbaFix (for animals receiving Ventralight ST) or Securestrap (for animals receiving Physiomesh). There were 5 animals in each group, yielding 10 of each mesh-fixation combination. Mesh contracture, adhesion characteristics, tissue ingrowth, and histologic response were evaluated after 14 days by image analysis, mechanical testing, and histologic staining (hematoxylin-eosin, Masson trichrome, picrosirius red, and von Willebrand factor).

Results:

Ventralight ST/SorbaFix and Physiomesh/Securestrap exhibited a similar percentage of mesh contracture, percentage of adhesion coverage, adhesion tenacity, collagen deposition, and levels of necrosis (P > .05 in all cases). However, Ventralight ST/SorbaFix exhibited significantly less inflammation (P = .0001), fibrosis (P = .0017), hemorrhage (P = .0001), and angiogenesis (P = .0032) and significantly greater strength of tissue ingrowth (P = .0003) than Physiomesh/Securestrap after the 14-day implantation period.

Conclusions:

Ventralight ST/SorbaFix exhibited more favorable strength of tissue ingrowth and histologic response and similar mesh contracture and adhesion characteristics compared with Physiomesh/Securestrap over a short-term 14-day implantation period in a preclinical porcine model.

A material cost-minimization analysis for hernia repairs and minor procedures during a surgical mission in the Dominican Republic

INTRODUCTION

Expenditures on material supplies and medications constitute the greatest per capita costs for surgical missions. We hypothesized that supply acquisition at non-profit organization (NPO) costs would lead to significant cost-savings compared with supply acquisition at US academic institution costs from the provider perspective for hernia repairs and minor procedures during a surgical mission in the Dominican Republic.

METHODS

Items acquired for a surgical mission were uniquely QR-coded for accurate consumption accounting. Both NPO and US academic institution unit costs were associated with each item in an electronic inventory system. Medication doses were recorded and QR codes for consumed items were scanned into a record for each sampled procedure. Mean material costs and cost-savings ± SDs were calculated in US dollars for each procedure type. Cost-minimization analyses between the NPO and the US academic institution platforms for each procedure type ensued using a two-tailed Wilcoxon matched-pairs test with α = 0.05. Item utilization analyses generated lists of most frequently used materials by procedure type.

RESULTS

The mean cost-savings of supply acquisition at NPO costs for each procedure type were as follows: $482.86 ± $683.79 for unilateral inguinal hernia repair (n = 13); $332.46 ± $184.09 for bilateral inguinal hernia repair (n = 3); $127.26 ± $13.18 for hydrocelectomy (n = 9); $232.92 ± $56.49 for femoral hernia repair (n = 3); $120.90 ± $30.51 for umbilical hernia repair (n = 8); $36.59 ± $17.76 for minor procedures (n = 26); and $120.66 ± $14.61 for pediatric inguinal hernia repair (n = 7).

CONCLUSION

Supply acquisition at NPO costs leads to significant cost-savings compared with supply acquisition at US academic institution costs from the provider perspective for inguinal hernia repair, hydrocelectomy, umbilical hernia repair, minor procedures, and pediatric inguinal hernia repair during a surgical mission in the Dominican Republic. Item utilization analysis can generate minimum-necessary material lists for each procedure type to reproduce cost-savings for subsequent missions.

Laparoscopic adrenalectomy for cancer

Laparoscopic procedures are preferred by surgeons and patients alike because of decreased pain, reduced perioperative morbidity, and an earlier return to self-reliance. During the last decade, laparoscopic adrenalectomy has become the technique most commonly used for the removal of benign adrenal tumors. The indications for laparoscopy in malignant adrenal tumors remains controversial, because oncologic resections have not been reproducible compared with open techniques.

Risk factors affecting operative approach, conversion, and morbidity for adrenalectomy: a single-institution series of 402 patients

BACKGROUND

Risk factors for selecting patients for open adrenalectomy (OA) and for conversion are limited in most series. This study aimed to investigate variables that are important in selecting patients for OA, predict risk of conversion from laparoscopic adrenalectomy (LA), and impact 30-day outcomes of OA and LA.

METHODS

A retrospective cohort study of prospectively collected data was conducted. Patients (≥ 16 years old) who underwent adrenalectomy in the Division of General Surgery at Barnes-Jewish Hospital (1993-2010) were grouped by operative approach (LA vs. OA) and compared using nonparametric tests and regression analyses (α < 0.05).

RESULTS

In total, 402 patients underwent 422 adrenalectomies. Compared to LA patients, those in the OA group were older (p = 0.02), had higher ASA scores (p = 0.04), larger tumor size (p < 0.01), and fewer functioning lesions (p < 0.01). OA patients more often required concurrent procedures (p < 0.01), had a longer operative time (p = 0.04), more intraoperative complications (p = 0.02), higher estimated blood loss (EBL), and larger transfusion requirement. Preoperative factors that predicted selection for OA were higher patient age (p = 0.01), higher ASA score (p = 0.03), larger tumor size (p < 0.01), nonfunctioning lesion (p < 0.01), diagnosis of adrenocortical carcinoma (p < 0.01), and the need for concomitant procedures (p < 0.01). Conversion to open or hand-assisted approach occurred in 6.2 % of LA patients. Preoperative risks for conversion included large tumor size (>8 cm) and need for concomitant procedures (p < 0.01). Multivariate analysis revealed that large indeterminate adrenal mass, adrenocortical carcinoma, tumor size (>6 cm), an open operation, conversion, concomitant procedures, operative time >180 min, and EBL >200 mL were predictors of 30-day morbidity.

CONCLUSIONS

Adrenal tumor size and need for concurrent procedures significantly impact the selection of patients for OA, the likelihood of conversion, and perioperative morbidity. These metrics should be considered when assessing operative approach and risks for adrenalectomy.

Laparoscopic fixation of biologic mesh at the hiatus with fibrin or polyethylene glycol sealant in a porcine model

BACKGROUND

The objective of this study was to determine the acute and chronic fixation strengths achieved by fibrin or polyethylene glycol (PEG) sealants to secure biologic mesh at the esophageal hiatus in a porcine model.

METHODS

For this study, 32 female domestic pigs were divided into four groups of 8 each. The four groups respectively received acute fibrin sealant, acute PEG sealant, chronic fibrin sealant, and chronic PEG sealant. Laparoscopically, a 5.5 × 8.5-cm piece of Biodesign Surgisis Hiatal Hernia Graft (porcine small intestine submucosa) was oriented with the U-shaped cutout around the gastroesophageal junction and the short axis in the craniocaudal direction to simulate hiatal reinforcement with a biologic mesh. The mesh then was secured with 2 ml of either fibrin sealant or PEG sealant. The pigs in the acute groups were maintained alive for 2 h to allow for complete polymerization of the sealants, and the pigs in the chronic group were maintained alive for 14 days. After the pigs were euthanized, specimens of the mesh-tissue interface were subjected to lap shear testing to determine fixation strength, and hematoxylin and eosin (H&E) stained slides were evaluated for evidence of remodeling.

RESULTS

No significant differences were observed between the acute and chronic fixation strengths or the remodeling characteristics of the two sealants. However, fixation strength increased significantly over time for both types of sealant. Evidence of remodeling also was significantly more pronounced in the chronic specimens than in the acute specimens.

CONCLUSIONS

This study demonstrated the feasibility of using fibrin or PEG sealants to secure biologic mesh at the hiatus in a porcine model.

A review of the composition, characteristics, and effectiveness of barrier mesh prostheses utilized for laparoscopic ventral hernia repair

BACKGROUND

The objective of this review was to provide an overview of the components that comprise each of the eight barrier mesh prostheses commonly utilized for LVHR and to review the current literature related to the characteristics and effectiveness of these materials to guide the general surgeon in selecting the most appropriate material for LVHR.

METHODS

Composite prostheses with permanent barriers (Bard™ Composix™ E/X, Bard™ Composix™ L/P, and DUALMESH(®) Biomaterial) were compared to composite prostheses with absorbable barriers (C-QUR™ Mesh, PROCEED™ Surgical Mesh, Bard™ Sepramesh™ IP Composite, Parietex™ Composite, and PHYSIOMESH™) using scanning electron microscopy and a review of the current preclinical and clinical literature.

RESULTS

Clinical studies and preclinical animal models have attempted to determine the adhesion characteristics and effectiveness of barrier mesh prostheses available for ventral hernia repair applications. However, it is difficult to make any definitive statements about the adhesion characteristics and effectiveness of these materials because all meshes were not included in all studies and likewise not compared under identical conditions. Overall, Parietex™ Composite and DUALMESH(®) Biomaterial were cited most frequently for improvement of adhesion characteristics, followed closely by Bard™ Sepramesh™ IP Composite and C-QUR™ Mesh. Bard™ Composix™, PROCEED™ Surgical Mesh, and uncoated polypropylene were cited most frequently as having the most tenacious and extensive adhesions.

CONCLUSIONS

Differences observed between the various barrier prostheses are likely attributable to the chemical composition of the barrier or the conditions required for resorption and metabolism of the barrier components. It is likely that the components of these barriers incite a wide range of inflammatory responses resulting in the range of adhesion coverage and tenacity observed in the preclinical and clinical studies reviewed. Clinical trials are needed to more appropriately define the clinical effectiveness of these barriers.

Laparoscopic Dor versus Toupet fundoplication following Heller myotomy for achalasia: results of a multicenter, prospective, randomized-controlled trial

BACKGROUND

The type of fundoplication that should be performed in conjunction with Heller myotomy for esophageal achalasia is controversial. We prospectively compared anterior fundoplication (Dor) with partial posterior fundoplication (Toupet) in patients undergoing laparoscopic Heller myotomy.

METHODS

A multicenter, prospective, randomized-controlled trial was initiated to compare Dor versus Toupet fundoplication after laparoscopic Heller myotomy. Outcome measures were symptomatic GERD scores (0-4, five-point Likert scale questionnaire) and 24-h pH testing at 6-12 months after surgery. Data are mean ± SD. Statistical analysis was by Mann-Whitney U test, Wilcoxon signed rank test, and Freidman's test.

RESULTS

Sixty of 85 originally enrolled and randomized patients who underwent 36 Dor and 24 Toupet fundoplications had follow-up data per protocol for analysis. Dor and Toupet groups were similar in age (46.8 vs. 51.7 years) and gender (52.8 vs. 62.5% male). pH studies at 6-12 months in 43 patients (72%: Dor n = 24 and Toupet n = 19) showed total DeMeester scores and % time pH < 4 were not significant between the two groups. Abnormal acid reflux was present in 10 of 24 Dor group patients (41.7%) and in 4 of 19 Toupet patients (21.0%) (p = 0.152). Dysphagia and regurgitation symptom scores improved significantly in both groups compared to preoperative scores. No significant differences in any esophageal symptoms were noted between the two groups preoperatively or at follow-up. SF-36 quality-of-life measures changed significantly from pre- to postoperative for five of ten domains in the Dor group and seven of ten in the Toupet patients (not significant between groups).

CONCLUSION

Laparoscopic Heller myotomy provides significant improvement in dysphagia and regurgitation symptoms in achalasia patients regardless of the type of partial fundoplication. Although a higher percentage of patients in the Dor group had abnormal 24-h pH test results compared to those of patients who underwent Toupet, the differences were not statistically significant.

Biomechanical evaluation of potential damage to hernia repair materials due to fixation with helical titanium tacks

BACKGROUND

This study aimed to determine whether the strength and extensibility of hernia repair materials are negatively influenced by the application of helical titanium tacks.

METHODS

This study evaluated 14 meshes including bare polypropylene, macroporous polytetrafluoroethylene, absorbable barrier, partially absorbable mesh, and expanded polytetrafluoroethylene materials. Each mesh provided 15 specimens, which were prepared in 7.5 × 7.5-cm squares. Of these, 5 "undamaged" specimens were subjected to ball-burst testing to determine their biomechanical properties before application of helical titanium tacks (ProTack). To 10 "damaged" specimens 7 tacks were applied 1 cm apart in a 3.5-cm-diameter circle using a tacking force of 25 to 28 N. The tacks were removed from five of the specimens before ball-burst testing and left intact in the remaining five specimens.

RESULTS

The application of tacks had no effect on the tensile strength of Dualmesh, ProLite Ultra, Infinit, Ultrapro, C-QUR Lite (<6 in.), Prolene Soft, or Physiomesh, but the tensile strengths were reduced for Bard Mesh, C-QUR, ProLite, and C-QUR Lite (>6 in.). Most of the meshes did not exhibit significantly different tensile strengths between removal of tacks and tacks left intact. Exceptions included C-QUR, Prolene, Ultrapro, and Bard Soft Mesh, which were weaker with removal of tacks than with tacks left intact during the test. Damage due to the application of helical titanium tacks also caused increased strain at a stress of 16 N/cm for all the meshes except C-QUR Lite (>6 in.) and Physiomesh.

CONCLUSIONS

Many of the meshes evaluated in this study exhibited damage in the form of reduced tensile strength and increased extensibility after the application of tacks compared with the corresponding "undamaged" meshes. Meshes with smaller interstices and larger filaments were influenced negatively by the application of helical titanium tacks, whereas mesh designs with larger interstices and smaller filaments tended to maintain their baseline mechanical properties.

Clinical outcomes of atypical extra-esophageal reflux symptoms following laparoscopic antireflux surgery

INTRODUCTION

While it is well established that antireflux surgery is effective in relieving typical gastroesophageal reflux disease (GERD) symptoms such as heartburn and regurgitation, it is currently unclear whether atypical symptoms (cough, hoarseness, wheeze) foreshadow a less satisfactory outcome following laparoscopic antireflux surgery (LARS). The purpose of this study is to critically analyze the clinical outcomes of atypical symptoms in patients undergoing LARS.

METHODS

Patients scheduled for LARS for GERD were prospectively enrolled over a 7-year period; all subjects underwent preoperative high-resolution manometry (HRM) and had evidence of GERD on ambulatory pH study. Cough, wheeze, and hoarseness were considered atypical symptoms. During preoperative and postoperative examinations, patients completed detailed foregut symptomatology questionnaires, using both 5-point Likert and 10-point visual analog scales (VAS) to document typical as well as atypical symptoms. Atypical symptom burden was calculated as a sum of VAS for the three atypical symptoms, termed the atypical score (ATS). HRM patterns were grouped into normal, spastic, and hypomotile. Statistical significance (p < 0.05) was determined using paired t-test, and analysis of variance with post hoc least significant difference (LSD).

RESULTS

One hundred thirteen patients (age 49 ± 1.26 years, range 20-84 years, M:F 47:66) with mean follow-up of 28 ± 2.31 months (range 1-92 months) fulfilled inclusion criteria, having mean modified DeMeester score of 45.5 ± 2.78. Heartburn was noted in 84.1%, while atypical symptoms of some degree were reported by 92.0% (104 patients). Heartburn improved from a preoperative score of 7.1 ± 0.54 to 0.9 ± 0.24 after LARS, and ATS improved from 8.9 ± 0.71 to 2.2 ± 0.42. Significant improvements were noted for all atypical symptoms analyzed (p < 0.0001 for each). Improvement in atypical symptoms was least in the presence of hypomotility features on HRM (21.7% improvement), compared with normal motility (72.4%) and spastic features (83.9%). Preoperative atypical score (p < 0.0001) and esophageal hypomotility (p = 0.04) demonstrated a linear relationship with postoperative atypical score.

CONCLUSIONS

In an unselected cohort of patients undergoing LARS, atypical GERD symptoms improved as significantly as typical symptoms. Symptom improvement was significantly lower in the presence of esophageal hypomotility and with higher symptomatic state. Therefore, patients with severe atypical symptoms or hypomotile esophagus may not achieve the same clinical satisfaction from LARS.

Effect of repetitive loading on the mechanical properties of synthetic hernia repair materials

BACKGROUND

Hernia repair materials undergo repeated loading while in the body, and the impact on mechanical properties is unknown. It was hypothesized that exposure to repetitive loading would lead to decreased tensile strength and increased strain, and that these differences would become more pronounced with greater loading and unloading sequences.

STUDY DESIGN

Polypropylene, expanded polytetrafluoroethylene, composite barrier, and partially absorbable meshes were evaluated. Twenty specimens (7.5 × 7.5 cm) were prepared from each material. Five specimens were subjected to ball burst testing to determine baseline biomechanical properties. Cycles of 10, 100, and 1,000 loading sequences were also performed (n = 5 each).

RESULTS

BardMesh (CR Bard/Davol), Dualmesh (WL Gore), and Prolene (Ethicon) exhibited significantly reduced tensile strength; BardMesh, Proceed (Ethicon), Prolene, ProLite (Atrium Medical), ProLite Ultra (Atrium Medical), and Ultrapro (Ethicon) exhibited significantly increased strain after exposure to 1,000 cycles compared with their baseline properties. BardMesh and Prolene demonstrated both reduced tensile strength and increased strain values after 1,000 cycles, suggesting that repetitive loading has the greatest effects on these materials. In addition, BardMesh and Prolene exhibited progressively worsening effects as the number of cycles was increased.

CONCLUSIONS

Deterioration of the tensile strength of the mesh or an increase in the ability of the mesh material to stretch (ie, increased strain values) could potentially lead to hernia recurrence or a poor functional result. However, the results of this study should not be interpreted to mean that hernia repair materials will fail in the body after only 10, 100, or 1,000 cycles. The conditions used in this study were more extreme than most physiologic scenarios and were intended as a pilot investigation into how the mechanical properties of hernia repair materials are affected by in vitro cyclic testing.

Histologic evaluation of absorbable and non-absorbable barrier coated mesh secured to the peritoneum with fibrin sealant in a New Zealand white rabbit model

PURPOSE

The purpose of this study is to evaluate the histologic response to fibrin sealant (FS) as an alternative fixation method for laparoscopic ventral hernia repair.

METHODS

One non-absorbable barrier mesh (Composix™) and three absorbable barrier meshes (Sepramesh™, Proceed™, and Parietex™ Composite) were used for the study, with uncoated macroporous polypropylene mesh (ProLite Ultra™) as the control. Three methods of fixation were used: #0-polypropylene suture + FS (ARTISS™, Baxter Healthcare Corp.), FS alone (ARTISS™), or tacks alone (n = 10 for each group). Two pieces of mesh (of dimensions 4 × 4-cm) were secured intraperitoneally in 75 New Zealand white rabbits. After 8 weeks, hematoxylin and eosin (H&E)-stained specimens were evaluated for host tissue response. Statistical significance (P < 0.05) was determined using a one-way analysis of variance (ANOVA) with Fisher's least significant difference (LSD) post hoc test.

RESULTS

Composix™ with FS only showed significantly greater cellular infiltration than with suture + FS (P = 0.0007), Proceed™ with FS only had significantly greater neovascularization than with suture + FS (P = 0.0172), and ProLite Ultra™ with suture + FS had significantly greater neovascularization than with tacks only (P = 0.046). Differences due to mesh type showed that Composix™ exhibited less extensive cellular infiltration (P ≤ 0.0032), extracellular matrix (ECM) deposition, and neovascularization, and demonstrated less inflammatory cells and more fibroblasts compared to the other meshes (P < 0.05).

CONCLUSIONS

FS did not have a significant histologic effect compared to tacks when utilized for the fixation of mesh to the peritoneum of New Zealand White rabbits. However, the mesh type did have a significant histologic effect. The permanent barrier mesh (Composix™) was associated with less histologic incorporation than absorbable barrier and macroporous meshes, as evidenced by lower levels of cellular infiltration, ECM deposition, and neovascularization, independent of the fixation method used.

Histologic and biomechanical evaluation of crosslinked and non-crosslinked biologic meshes in a porcine model of ventral incisional hernia repair

BACKGROUND

The objective of this study was to evaluate the biomechanical characteristics and histologic remodeling of crosslinked (Peri-Guard, Permacol) and non-crosslinked (AlloDerm, Veritas) biologic meshes over a 12 month period using a porcine model of incisional hernia repair.

STUDY DESIGN

Bilateral incisional hernias were created in 48 Yucatan minipigs and repaired after 21 days using an underlay technique. Samples were harvested at 1, 6, and 12 months and analyzed for biomechanical and histologic properties. The same biomechanical tests were conducted with de novo (time 0) meshes as well as samples of native abdominal wall. Statistical significance (p < 0.05) was determined using 1-way analysis of variance with a Fisher's least significant difference post-test.

RESULTS

All repair sites demonstrated similar tensile strengths at 1, 6, and 12 months and no significant differences were observed between mesh materials (p > 0.05 in all cases). The strength of the native porcine abdominal wall was not augmented by the presence of the mesh at any of the time points, regardless of de novo tensile strength of the mesh. Histologically, non-crosslinked materials showed earlier cell infiltration (p < 0.01), extracellular matrix deposition (p < 0.02), scaffold degradation (p < 0.05), and neovascularization (p < 0.02) compared with crosslinked materials. However, by 12 months, crosslinked materials showed similar results compared with the non-crosslinked materials for many of the features evaluated.

CONCLUSIONS

The tensile strengths of sites repaired with biologic mesh were not impacted by very high de novo tensile strength/stiffness or mesh-specific variables such as crosslinking. Although crosslinking distinguishes biologic meshes in the short-term for histologic features, such as cellular infiltration and neovascularization, many differences diminish during longer periods of time. Characteristics other than crosslinking, such as tissue type and processing conditions, are likely responsible for these differences.

Early biocompatibility of crosslinked and non-crosslinked biologic meshes in a porcine model of ventral hernia repair

PURPOSE

Biologic meshes have unique physical properties as a result of manufacturing techniques such as decellularization, crosslinking, and sterilization. The purpose of this study is to directly compare the biocompatibility profiles of five different biologic meshes, AlloDerm(®) (non-crosslinked human dermal matrix), PeriGuard(®) (crosslinked bovine pericardium), Permacol(®) (crosslinked porcine dermal matrix), Strattice(®) (non-crosslinked porcine dermal matrix), and Veritas(®) (non-crosslinked bovine pericardium), using a porcine model of ventral hernia repair.

METHODS

Full-thickness fascial defects were created in 20 Yucatan minipigs and repaired with the retromuscular placement of biologic mesh 3 weeks later. Animals were euthanized at 1 month and the repair sites were subjected to tensile testing and histologic analysis. Samples of unimplanted (de novo) meshes and native porcine abdominal wall were also analyzed for their mechanical properties.

RESULTS

There were no significant differences in the biomechanical characteristics between any of the mesh-repaired sites at 1 month postimplantation or between the native porcine abdominal wall without implanted mesh and the mesh-repaired sites (P > 0.05 for all comparisons). Histologically, non-crosslinked materials exhibited greater cellular infiltration, extracellular matrix (ECM) deposition, and neovascularization compared to crosslinked meshes.

CONCLUSIONS

While crosslinking differentiates biologic meshes with regard to cellular infiltration, ECM deposition, scaffold degradation, and neovascularization, the integrity and strength of the repair site at 1 month is not significantly impacted by crosslinking or by the de novo strength/stiffness of the mesh.

Physicomechanical evaluation of polypropylene, polyester, and polytetrafluoroethylene meshes for inguinal hernia repair

BACKGROUND

For meshes to be used effectively for hernia repair, it is imperative that engineers and surgeons standardize the terminology and techniques related to physicomechanical evaluation of these materials. The objectives of this study were to propose standard techniques, perform physicomechanical testing, and classify materials commonly used for inguinal hernia repair.

STUDY DESIGN

Nine meshes were evaluated: 4 polypropylene, 1 polyester, 1 polytetrafluoroethylene, and 3 partially absorbable. Physical properties were determined through image analysis, laser micrometry, and density measurements. Biomechanical properties were determined through suture retention, tear resistance, uniaxial, and ball burst testing with specimens tested in 2 different orientations. A 1-way ANOVA with Tukey's post-test or a t-test were performed, with p < 0.05.

RESULTS

Significant differences were observed due to both mesh type and orientation. Areas of interstices ranged from 0.33 ± 0.01 mm² for ProLite (Atrium Medical Corp) and C-QUR Lite (Atrium Medical Corp) Large to 4.10 ± 0.06 mm² for ULTRAPRO (Ethicon), and filament diameters ranged from 99.00 ±8.1 μm for ProLite Ultra (Atrium Medical Corp) and C-QUR Lite Small to 338.8 ± 3.7 μm for Parietex Flat Sheet TEC (Covidien). These structural characteristics influenced biomechanical properties such as tear resistance and tensile strength. ProLite Ultra, C-QUR Lite Small, ULTRAPRO and INFINIT (WL Gore & Associates) did not resist tearing as effectively as the others. All meshes exhibited supraphysiologic burst strengths except INFINIT and ULTRAPRO.

CONCLUSIONS

Significant differences exist between the physicomechanical properties of polypropylene, polyester, polytetrafluoroethylene, and partially absorbable mesh prostheses commonly used for inguinal hernia repair. Orientation of the mesh was also shown to be critical for the success of meshes, particularly those demonstrating anisotropy.

Collagen type I:III ratio of the gastroesophageal junction in patients with paraesophageal hernias

BACKGROUND

The purpose of this study was to examine the biological environment of the esophageal hiatus through analysis of the collagen content within the gastrohepatic ligament (GHL), gastrophrenic ligament (GPL), and phrenoesophageal ligament (PEL) in patients with type I hiatal hernias (HH) and type III paraesophageal hernias (PEH).

METHODS

A control group (N=10) and patients with type I HH (N=10) and type III PEH (N=10) were included in the analysis. Specimens of the GHL, PEL, and GPL were collected intraoperatively. Slides stained with sirius red/fast green were created and ten photos at 400×magnification were taken of each specimen. Axiovision 4.7 (Zeiss) photo analysis software was employed for quantification of collagen I (red) and III (green) by calculating color area (μm2). Statistical significance (p<0.05) was determined using a one-way ANOVA and Fisher's LSD post-test.

RESULTS

Cross-polarization microscopy revealed that the collagen I content was similar in the three study groups for the GHL, greater in the type III PEH group and in the control group compared to the type I HH group for the PEL, and greater in the type III PEH group compared to control group for the GPL. Collagen III quantity was greater in the control group than in the type I HH group for each ligament, and greater in the GHL and PEL when compared to the type III PEH group. Type III PEH patients had greater collagen III quantity than did type I HH patients for each ligament. Collagen type I:III ratio of the GHL was greater in both hernia groups compared to the control group. Type III PEH patients contained a higher I:III ratio than both the control and type I HH groups with respect to the PEL. There was no difference in the ratio with evaluation of the GPL for the three groups.

CONCLUSION

Evaluation of the esophageal hiatus revealed that patients with PEH have a different biological environment with regard to collagen content compared to control patients. The collagen I:III ratio of the study groups was equal to or greater than the control group. Collagen deficiency in the GE junction supporting ligaments does not appear to be an etiology of PEH formation.