Development of a Model for Abdominal Aortic Aneurysms in Swine.

INTRODUCTION: Producing a reliable large-animal model of AAA has proven challenging. We sought to create a reproducible swine model of AAA using enzymatic degradation of the aortic wall. METHODS: Twelve male Yorkshire swine received periadventitial injections of type 1 collagenase and porcine pancreatic elastase into a 4 cm segment of infrarenal aorta. Nine survived until postoperative day (POD) 21. Aortic growth was monitored at 7 and 14 days using ultrasound. The animals were euthanized on POD 21, and the suprarenal (control) and infrarenal aorta were harvested for analysis, after gross measurement of aortic diameter (AD). Tensile strength was measured and additional segments were collected for histopathological analysis. PCR of matrix metalloproteinases (MMP9) was conducted. Groups were compared with paired t-tests, or ANOVA, where appropriate. RESULTS: Average percent growth of AD at POD 21 for treated segments was 27% versus 4.5% for control tissue. The average difference in AD by subject, was 26.7% (P<0.001). Aortic medial thickness was decreased in treated tissue; 235 µm versus 645 µm (P<0.0001). Quantities of both medial elastin fibers, and smooth muscles cells were decreased in treated tissue; 1.8% compared to 9.9% (P<0.0001), and 24% versus 37.4%, respectively. Tensile strength was also decreased in treated tissue; 16.7 MPa versus 29.5 MPa (P=0.0002). A 12-fold increase in expression of MMP9 mRNA was also demonstrated in aneurysmal tissue (P=0.002) CONCLUSION: A reproducible, large-animal model of AAA, with anatomical, histopathological, and biomechanical properties that are clinically translatable, can be achieved with extraluminal enzymatic degradation.

Human Adipose Derived Stem Cells Enhance Healing in a Rat Model of Esophageal Injury with Stent.

BACKGROUND: Mesenchymal stem cells have been proven to promote cellular recruitment and remodeling during healing. Considering challenges encountered in the healing process of esophageal injury, we sought to evaluate the effect of human adipose derived stem cells (hASC) on esophageal injury with stent and to assess the feasibility of submucosal hASC injection as a mechanism of delivery. METHODS: An intrabdominal esophagotomy was created in rodents with placement of an expandable fully covered metal esophageal stent. A submucosal injection of 2 × 106 hASC was delivered in experimental animals. Animals were sacrificed on postoperative day 3 (POD3) or 7 (POD7). Macroscopic, immunohistochemical and immunofluorescence analyses were conducted to assess for markers of healing and viability of transplanted cells. RESULTS: hASC were identified within submucosal and muscular layers with proliferation demonstrated in respective areas on anti-Ki67 stained sections. Lower adhesion and abscess scores were observed in hASC specimens without significant statistical difference. Prevalence of submucosal collagen was increased in samples treated with hASC compared to control, with abundant collagen deposition demonstrated within the POD7 group. Granulation tissue at the site of esophageal injury was more prominent in tissue sections treated with hASC compared to control, with significantly higher density at POD3 (control 1.94 versus hASC 2.83, P < 0.01). CONCLUSIONS: Presence of hASC at the site of an esophageal injury may enhance wound healing predominantly through increased granulation and decreased inflammation in conjunction with esophageal stent placement. Targeted submucosal injection at the time of esophageal stent placement is an effective delivery method of hASC therapy.

Temporary intravascular shunts after civilian arterial injury: A prospective multicenter Eastern Association for the Surgery of Trauma study.

INTRODUCTION: We sought to determine the impact of the indication for shunt placement on shunt-related outcomes after major arterial injuries. We hypothesized that a shunt placed for damage control indications would be associated with an increase in shunt-related complications including shunt dislodgement, thrombosis, or distal ischemia. PATIENTS & METHODS: A prospective, multicenter study (eleven level one US trauma centers) of all adult trauma patients undergoing temporary intravascular shunts (TIVS) after arterial injury was undertaken (January 2017-May 2019). Exclusion criteria included age <15years, shunt placement distal to popliteal/brachial arteries, isolated venous shunts, and death before shunt removal. Clinical variables were compared by indication and shunt-related complications. The primary endpoint was TIVS complications (thrombosis, migration, distal ischemia). RESULTS: The 66 patients who underwent TIVS were primarily young (30years [IQR 22-36]) men (85%), severely injured (ISS 17 [10-25]) by penetrating mechanisms (59%), and had their shunts placed for damage control (41%). After a median SDT of 198min [89-622], 9% experienced shunt-related complications. Compared by shunt placement indication (damage control shunts [n=27] compared to non-damage control shunts [n=39]), there were no differences in gender, mechanism, extremity AIS, MESS score, fractures, or surgeon specialty between the two groups (all p>0.05). Patients with shunts placed for damage control indications had more severe injuries (ISS 23.5 compared to 13; SBP 100 compared to 129; GCS 11 compared to 15; lactate 11.5 compared to 3.6; all p<0.05), and had more frequent shunt complication predictors, but damage control shunts did not have significantly more TIVS complications (11.1% compared to 7.7%, p=0.658). Shunt complication patients were discharged home less often (33% vs 65%; p<0.05) but all survived. CONCLUSION: Shunts placed for damage control indications were not associated with shunt complications in this prospective, multicenter study.

The Role of Neoadjuvant Versus Adjuvant Therapy for Duodenal Adenocarcinoma: A National Cancer Database Propensity Score Matched Analysis.

INTRODUCTION: Adjuvant therapy is recommended in duodenal adenocarcinoma (DA), but the role of neoadjuvant therapy remains undefined. We compared the effect of neoadjuvant therapy to adjuvant therapy on overall survival, 30-day, and 90-day mortality following the resection of DA. METHODS: A retrospective review of the National Cancer Database was performed on patients with DA who received either adjuvant or neoadjuvant therapy in addition to surgical resection. Propensity score matching was done for patient, socioeconomic, and tumor characteristics. Overall survival, 30-day, and 90-day mortality were compared. RESULTS: A total of 112 patients were identified; 55 received adjuvant therapy; 57 received neoadjuvant therapy. There was no difference in 30-day (0% vs. 1.75%; P = 1.00), 90-day mortality (1.82% vs. 7.02%; P = .36), nor overall survival (1 yr: 86% vs. 76; 3 yr: 49% vs. 46%; 5 yr: 42% vs. 39%; P = .28). CONCLUSIONS: There was no difference in overall survival after propensity score matched analysis.

Necrotizing Soft Tissue Infections of the Upper Extremity.

Necrotizing soft tissue infections of the upper extremity have varying microbiologies and etiologies. Risk factors for development include diabetes mellitus, intravenous drug use, peripheral arterial disease, smoking, alcohol abuse, and immunocompromised state. Although clinical examination is the mainstay of diagnosis, laboratory tests and imaging can aid in diagnosis. Surgical débridements usually are needed for treatment, with resultant defects that often require reconstruction. Rates of amputation are reported as 22% to 37.5% and mortality from necrotizing soft tissue infections of the upper extremity from 22% to 34%. Prompt surgical and antimicrobial treatment is necessary to decrease risk of loss of limb or life.

Analysis of surgical options for patients with bilateral carpal tunnel syndrome.

BACKGROUND: Bilateral endoscopic carpal tunnel release is a modality offered for the treatment of the median nerve compression neuropathy. This retrospective study compares outcomes for patients undergoing open carpal tunnel release versus bilateral endoscopic carpal tunnel release. We hypothesized that there is no significant difference in postoperative complication rates between unilateral open and bilateral endoscopic carpal tunnel release surgery. METHODS: The authors identified all patients who underwent open carpal tunnel release, unilateral endoscopic carpal tunnel release and bilateral endoscopic carpal tunnel release at a university hospital from 2012 to 2014. Cases were identified using CPT billing codes and the data was assessed using an analysis of variance (ANOVA). All endoscopic carpal tunnel releases were done by the same surgeon (AP), and greater than 90% of open procedures were done by a different same surgeon (DF). RESULTS: The total combined complication rate was 24.7% with no significant difference (p > .05) between techniques. There were no major complications necessitating a return to the operating room. Variables that had a statistically significant difference between groups (p < .05) included mean tourniquet time, mean total procedure time, and return to work as determined from the number of follow-up appointments. CONCLUSIONS: The study demonstrates equivocal complication profiles and decreased cost associated with bilateral endoscopic tunnel release as compared to sequential open carpal tunnel release. Endoscopic bilateral carpal tunnel release for patients with bilateral carpal tunnel syndrome offers a safe and effective alternative to open carpal tunnel release.

Assessing trends, morbidity, and mortality in ruptured abdominal aortic aneurysm repair with 9 years of data from the National Surgical Quality Improvement Program.

BACKGROUND: The American College of Surgeons' National Quality Improvement Program (NSQIP) database can be used to assess trends and outcomes of ruptured abdominal aortic aneurysm (rAAA) repair. The purpose of this study is to examine the morbidity and mortality for ruptured endovascular (rEVAR) and ruptured open (rOPEN) aneurysm repair compared with elective endovascular (EVAR) and elective open (OPEN) aneurysm repair. METHODS: Ruptured and nonruptured abdominal aortic aneurysms were identified from the NSQIP database between 2008 and 2016. Data regarding demographics and comorbidities, 30-day mortality, and postoperative complications were collected for rEVAR, rOPEN, EVAR, and OPEN cases. RESULTS: There were 43,105 AAAs, 34,177 (79.28%) EVARs, and 8928 (20.71%) OPENs. There were 3806 rAAAs, 1843 (48.42%) rEVARs, and 1963 (51.58%) rOPENs. The incidence of rEVAR repair lagged behind EVAR considerably. Mortality for rOPEN was 575 (29.29%) and 344 (18.66%) for rEVAR. No difference between the ratio of men to women in rOPEN vs rEVAR was noted. There was a significant increase in mortality for women vs men undergoing rEVAR (P = .0362). No difference in mortality existed between women vs men undergoing rOPEN (P = .0639). There was no difference in the percentage of hypotensive cases undergoing rEVAR vs rOPEN (P =.1873). For all rAAAs with hypotension, rOPEN had an increased mortality compared to rEVAR (P = .0004). There were 20 (3.11%) rEVAR and 40 (8.00%) rOPEN cases with lower extremity ischemia. rOPEN conferred a significant increase in lower extremity ischemia (P = .0002). There were 46 (7.15%) rEVAR and 60 (12.00%) rOPEN cases of ischemic colitis. rOPEN had a significant increase in ischemic colitis (P = .0052). CONCLUSIONS: NSQIP data, over 9 years, demonstrate an increased morbidity and mortality associated with open vs endovascular repair of rAAAs. A great disparity exists between the proportion of rEVAR and rOPEN to EVAR and OPEN. The lagging use of endovascular repair of rAAAs must be further explored.

Bioionic Liquid Conjugation as Universal Approach To Engineer Hemostatic Bioadhesives.

Adhesion to wet and dynamic surfaces is vital for many biomedical applications. However, the development of effective tissue adhesives has been challenged by the required combination of properties, which includes mechanical similarity to the native tissue, high adhesion to wet surfaces, hemostatic properties, biodegradability, high biocompatibility, and ease of use. In this study, we report a novel bioinspired design with bioionic liquid (BIL) conjugated polymers to engineer multifunctional highly sticky, biodegradable, biocompatible, and hemostatic adhesives. Choline-based BIL is a structural precursor of the phospholipid bilayer in the cell membrane. We show that the conjugation of choline molecules to naturally derived polymers (i.e., gelatin) and synthetic polymers (i.e., polyethylene glycol) significantly increases their adhesive strength and hemostatic properties. Synthetic or natural polymers and BILs were mixed at room temperature and cross-linked via visible light photopolymerization to make hydrogels with tunable mechanical, physical, adhesive, and hemostatic properties. The hydrogel adhesive exhibits a close to 50% decrease in the total blood volume loss in tail cut and liver laceration rat animal models compared to the control. This technology platform for adhesives is expected to have further reaching application vistas from tissue repair to wound dressings and the attachment of flexible electronics.