Thick silk fibroin vascular graft: A promising tissue-engineered scaffold material for abdominal vein grafts in middle-sized mammals.

Abdominal vein replacement with synthetic tissue-engineered vascular grafts constructed from silk-based scaffold material has not been reported in middle-sized mammals. Fourteen canines that underwent caudal vena cava replacement with a silk fibroin (SF) vascular graft (15 mm long and 8 mm diameter) prepared with natural silk biocompatible thread were allocated to two groups, thin and thick SF groups, based on the graft wall thickness. The short-term patency rate and histologic reactions were compared. The patency rate at 2 weeks after replacement in the thin and thick SF groups was 50% and 88%, respectively (p = 0.04). CD31-positive endothelial cells covered the luminal surface of both groups at 4 weeks. The elastic modulus of the thick SF graft was significantly better than that of the thin SF graft (0.0210 and 0.0007 N/m2, p < 0.01). Roundness of thick SF groups (o = 0.8 mm) was better than thin SF (o = 2.0 mm). There was significant difference between the groups (p = 0.01). SF vascular grafts are a promising tissue-engineered scaffold material for abdominal venous system replacement in middle-sized mammals, with thick-walled grafts being superior to thin-walled grafts.

Atypical Splenic Abscesses Due to Clostridioides difficile.

BACKGROUND Splenic abscess is a rare infectious disease that occurs after bloodstream infection and trauma. It has become more common due to an increase in the number of immunocompromised patients. They typically present with round cystic lesions demonstrated by ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). Clostridioides difficile (formerly Clostridium difficile) is a well-known cause of pseudomembranous colitis, but extraintestinal manifestations are very rare. To the best of our knowledge, only 9 cases of splenic abscess due to C. difficile have been reported in the literature. CASE REPORT A 90-year-old man presented with weight loss, fever, and abdominal pain. Contrast-enhanced CT revealed splenomegaly with irregular hypodense nodules. Image-guided biopsy or drainage was not performed for a technical reason. MRI showed atypical nodules with mixed high and low signals on both T1- and T2-weighted images, which were inconclusive. A laparoscopic splenectomy was performed, which resulted in partial removal due to severe adhesion of the spleen to the surrounding tissues. Cultures of splenic pus yielded C. difficile, Enterococcus faecium, and Bacteroides fragilis. Pathological examination of the spleen showed widespread abscesses with hemorrhage and necrosis, leading to the diagnosis of splenic abscesses. Intravenous administration of vancomycin, clindamycin or metronidazole was ineffective. He died of fatal arrhythmia 5 months after the initial diagnosis of splenic abscess. CONCLUSIONS Splenic abscess can present with atypical imaging findings owing to chronic inflammation, bleeding, and necrosis. Although polymicrobial, this is the tenth reported case of splenic abscess caused by C. difficile.

Hyaluronic acid/ carboxymethyl cellulose-based adhesion barrier reduces surgical difficulty and complication in repeat hepatectomy.

BACKGROUND: There has been no solid evidence regarding the actual efficacy of adhesion barriers in liver surgery. METHODS: Difficulty grade of lysis of adhesion was evaluated in 122 patients who underwent repeat hepatectomy (ReHx) using the TORAD score. Technical difficulty of lysis of adhesion and incidence of complication were then compared between the group of patients who received a sheet-type adhesion barrier (Seprafilm®) in the previous hepatectomy (n = 70) and those who did not (n = 52) using the inverse probability weighting method. RESULTS: Use of Seprafilm was significantly associated with lower grade of difficulty of lysis of adhesion according to the TORAD score (P < 0.001). Postoperative morbidity rate was lower and postoperative stay was shorter in the Seprafilm group in the propensity-score adjusted population (37% vs. 74%, P < 0.001 and 12 days vs. 14 days in median, P = 0.048). Multivariate analysis confirmed that use of Seprafilm was independent predictor for severity of adhesion (odds ratio [OR] 0.24, 95% CI, 0.09-0.65, P = 0.005) and decreased incidence of postoperative morbidity at ReHx (OR, 0.34; 95% CI, 0.14-0.84, P = 0.020). CONCLUSIONS: Use of Seprafilm may be associated with decreased technical difficulty of lysis of adhesion and may correlate with lower risk of postoperative morbidity in patients undergoing ReHx.

Silk fibroin vascular graft: a promising tissue-engineered scaffold material for abdominal venous system replacement.

No alternative tissue-engineered vascular grafts for the abdominal venous system are reported. The present study focused on the development of new tissue-engineered vascular graft using a silk-based scaffold material for abdominal venous system replacement. A rat vein, the inferior vena cava, was replaced by a silk fibroin (SF, a biocompatible natural insoluble protein present in silk thread), tissue-engineered vascular graft (10 mm long, 3 mm diameter, n = 19, SF group). The 1 and 4 -week patency rates and histologic reactions were compared with those of expanded polytetrafluoroethylene vascular grafts (n = 10, ePTFE group). The patency rate at 1 and 4 weeks after replacement in the SF group was 100.0% and 94.7%, and that in the ePTFE group was 100.0% and 80.0%, respectively. There was no significant difference between groups (p = 0.36). Unlike the ePTFE graft, CD31-positive endothelial cells covered the whole luminal surface of the SF vascular graft at 4 weeks, indicating better endothelialization. SF vascular grafts may be a promising tissue-engineered scaffold material for abdominal venous system replacement.