The Ferguson Operating Anoscope for Resection of T1 Rectal Cancer

The Ferguson Operating Anoscope (FOA) is a surgical instrument, which can facilitate transanal excision of appropriate rectal tumors within 15 cm of the anal verge. Previous work showed low recurrence (4.3%) for favorable T1 tumors (no lymphovascular invasion, well/moderate differentiation, negative margins). This follow-up study evaluates outcomes in rectal cancer excised with FOA at a tertiary care center. T1 rectal cancer patients were identified in a prospectively maintained database. Tumor pathology and patient characteristics were reviewed. Primary outcomes include tumor recurrence and patient and disease-free survival. Secondary outcomes are quality of excision (intact specimen). Twenty-eight patients had pathologic stage T1 rectal cancer (average 8 ± 2.6 cm from the anal verge). Final path demonstrated 14 per cent to be well differentiated, 82 per cent moderately differentiated, and 93 per cent without angiolymphatic invasion. All specimens removed were intact. One patient had a true local recurrence and underwent a salvage operation 24 months after her index operation. Patient survival was 96.4 per cent (n = one death from primary lung cancer) at median follow-up 64 ± 35 months. With appropriate tumor selection and quality of initial resection, FOA has demonstrated utility in achieving optimal oncologic resection of T1 rectal tumors.

Engineering vascularized soft tissue flaps in an animal model using human adipose-derived stem cells and VEGF+PLGA/PEG microspheres on a collagen-chitosan scaffold with a flow-through vascular pedicle

Insufficient neovascularization is associated with high levels of resorption and necrosis in autologous and engineered fat grafts. We tested the hypothesis that incorporating angiogenic growth factor into a scaffold-stem cell construct and implanting this construct around a vascular pedicle improves neovascularization and adipogenesis for engineering soft tissue flaps. Poly(lactic-co-glycolic-acid/polyethylene glycol (PLGA/PEG) microspheres containing vascular endothelial growth factor (VEGF) were impregnated into collagen-chitosan scaffolds seeded with human adipose-derived stem cells (hASCs). This setup was analyzed in vitro and then implanted into isolated chambers around a discrete vascular pedicle in nude rats. Engineered tissue samples within the chambers were harvested and analyzed for differences in vascularization and adipose tissue growth. In vitro testing showed that the collagen-chitosan scaffold provided a supportive environment for hASC integration and proliferation. PLGA/PEG microspheres with slow-release VEGF had no negative effect on cell survival in collagen-chitosan scaffolds. In vivo, the system resulted in a statistically significant increase in neovascularization that in turn led to a significant increase in adipose tissue persistence after 8 weeks versus control constructs. These data indicate that our model-hASCs integrated with a collagen-chitosan scaffold incorporated with VEGF-containing PLGA/PEG microspheres supported by a predominant vascular vessel inside a chamber-provides a promising, clinically translatable platform for engineering vascularized soft tissue flap. The engineered adipose tissue with a vascular pedicle could conceivably be transferred as a vascularized soft tissue pedicle flap or free flap to a recipient site for the repair of soft-tissue defects.

Adipose-derived stem-cell-seeded non-cross-linked porcine acellular dermal matrix increases cellular infiltration, vascular infiltration, and mechanical strength of ventral hernia repairs

Adipose-derived stem cells (ASCs) facilitate wound healing by improving cellular and vascular recruitment to the wound site. Therefore, we investigated whether ASCs would augment a clinically relevant bioprosthetic mesh-non-cross-linked porcine acellular dermal matrix (ncl-PADM)-used for ventral hernia repairs in a syngeneic animal model. ASCs were isolated from the subcutaneous adipose tissue of Brown Norway rats, expanded, and labeled with green fluorescent protein. ASCs were seeded (2.5×10(4) cells/cm(2)) onto ncl-PADM for 24 h before surgery. In vitro ASC adhesion to ncl-PADM was assessed at 0.5, 1, and 2 h after seeding, and cell morphology on ncl-PADM was visualized by scanning electron microscopy. Ventral hernia defects (2×4 cm) were created and repaired with ASC-seeded (n=31) and control (n=32) ncl-PADM. Explants were harvested at 1, 2, and 4 weeks after surgery. Explant remodeling outcomes were evaluated using gross evaluation (bowel adhesions, surface area, and grade), histological analysis (hematoxylin and eosin and Masson's trichrome staining), immunohistochemical analysis (von Willebrand factor VIII), fluorescent microscopy, and mechanical strength measurement at the tissue-bioprosthetic mesh interface. Stem cell markers CD29, CD90, CD44, and P4HB were highly expressed in cultured ASCs, whereas endothelial and hematopoietic cell markers, such as CD31, CD90, and CD45 had low expression. Approximately 85% of seeded ASCs adhered to ncl-PADM within 2 h after seeding, which was further confirmed by scanning electron microcopy examination. Gross evaluation of the hernia repairs revealed weak omental adhesion in all groups. Ultimate tensile strength was not significantly different in control and treatment groups. Conversely, elastic modulus was significantly greater at 4 weeks postsurgery in the ASC-seeded group (p<0.001). Cellular infiltration was significantly higher in the ASC-seeded group at all time points (p<0.05). Vascular infiltration was significantly greater at 4 weeks postsurgery in the ASC-seeded group (p<0.001). The presence of ASCs improved remodeling outcomes by yielding an increase in cellular infiltration and vascularization of ncl-PADM and enhanced the elastic modulus at the ncl-PADM-tissue interface. With the ease of harvesting adipose tissues that are rich in ASCs, this strategy may be clinically translatable for improving ncl-PADM ventral hernia repair outcomes.

Infectious complications in living-donor kidney transplant recipients undergoing multi-modal desensitization

BACKGROUND

Pre-existing humoral barriers challenge the transplantation of living donor kidneys (LDK) into highly sensitized ABO- and human leukocyte antigen (HLA)-incompatible recipients. Conditioning these LDK recipients' immune systems is required before they undergo transplantation. We hypothesized that medical desensitization would yield higher post-transplantation rates of infection.

METHODS

We conducted a study in which matched controls consisting of non-desensitized (NDS) LDK recipients were compared with desensitized (DS) receipients. Pre-transplantation desensitization included treatment with rituximab and mycophenolate mofetil followed by intravenous immunoglobulin (IVIg) and plasmapheresis. All participants in the study underwent induction therapy and maintenance immunosuppression. Primary outcomes included infection (opportunistic, local, systemic) within 12 mo after transplantation.

RESULTS

Twenty-five patients underwent desensitization and LDK transplantation. Graft survival in the DS and NDS groups of patients was 96% and 98%, respectively. The mean 3- and 12-mo serum creatinine concentrations in the DS and NDS groups were 1.1±0.2 mg/dL and 1.2±0.3 mg/dL and 0.95±0.4 mg/dL and 0.73±0.8 mg/dL (p=0.3 and p=0.01), respectively. Thirty-six percent of the patients in the DS group had one or more infections, vs. 28% of those in the NDS group (p=0.1). No difference was observed in the frequency of opportunistic or systemic infections in the two groups. Local infections were statistically significantly more frequent in the DS group (60% vs. 30%, respectively; p=0.02).

CONCLUSION

Pre-operative desensitization in highly sensitized LDK recipients is followed by a similar incidence of opportunistic and systemic infections as in NDS patients. Local infections were significantly more frequent in the DS than in the NDS patients in the study. With careful monitoring of infectious complications, pre-transplant desensitization permits LDK transplantation into highly sensitized patients.

Pneumomediastinum after percutaneous endoscopic gastrostomy tube placement

The incidence of esophageal perforation or confounding mechanisms of pneumomediastinum specifically introduced by the addition of percutaneous endoscopic gastrostomy (PEG) tube insertion to esophagogastroduodenoscopy have not been described, and pneumomediastinum in the absence of esophageal perforation after PEG has not been reported. Typically, pneumomediastinum is an ominous finding, although benign causes exist. We present two cases of post-PEG pneumomediastinum not correlated with esophageal perforation on follow-up imaging. When pneumomediastinum is detected after PEG, appropriate studies should be undertaken to confirm its cause and to determine treatment plans. Further investigation may be warranted to ascertain the true incidence, causes, and clinical significance of post-PEG pneumomediastinum.

Options for closure of the infected abdomen

BACKGROUND

The infected abdomen poses substantial challenges to surgeons, and often, both temporary and definitive closure techniques are required. We reviewed the options available to close the abdominal wall defect encountered frequently during and after the management of complicated intra-abdominal infections.

METHODS

A comprehensive review was performed of the techniques and literature on abdominal closure in the setting of intra-abdominal infection.

RESULTS

Temporary abdominal closure options include the Wittmann Patch, Bogota bag, vacuum-assisted closure (VAC), the AbThera™ device, and synthetic or biologic mesh. Definitive reconstruction has been described with mesh, components separation, and autologous tissue transfer.

CONCLUSION

Reconstructing the infected abdomen, both temporarily and definitively, can be accomplished with various techniques, each of which is associated with unique advantages and disadvantages. Appropriate judgment is required to optimize surgical outcomes in these complex cases.

A comparative analysis between laparoscopic and open ventral hernia repair at a tertiary care center

Laparoscopic ventral hernia repair reportedly yields lower postoperative complications than open repair. We hypothesized that patients undergoing laparoscopic repair would have lower postoperative infectious outcomes. Also, certain preoperative patient characteristics and preoperative hernia characteristics are hypothesized to increase complication risk in both groups. All ventral hernia repairs performed at University of Virginia from January 2004 to January 2006 were reviewed. Primary outcomes included wound healing complications and hernia recurrence. Categorical data were analyzed with χ(2) and Fisher's exact tests. Continuous variables were evaluated with independent t tests and Mann-Whitney U tests. Multivariable logistic regression was performed. A total of 268 repairs (110 open, 158 laparoscopic) were evaluated. Patient and hernia characteristics were similar between groups, though the percents of wound contamination (5.4% vs 0.6%; P = 0.02) and simultaneous surgery (7.2% vs 0%; P = 0.001) were greater in the open procedures. Univariate analysis also revealed that open cases had a greater incidence of postoperative superficial surgical site infection (SSI) (30.0% vs 10.7%; P < 0.0001). Multivariable analysis revealed that both diabetes and open repair were associated with an increased risk of superficial SSI (P = 0.019; odds ratio = 3.512; 95% confidence interval = 1.229-10.037 and P = 0.001; odds ratio = 4.6; 95% confidence interval = 1.9-11.2, respectively). Laparoscopic ventral hernia repair yielded lower rates of postoperative superficial SSI than open surgery. Other preoperative patient characteristics and preoperative hernia characteristics, with the exception of diabetes, were not found to be associated with an increased risk of postoperative complications.

A Comparative Analysis between Laparoscopic and Open Ventral Hernia Repair at a Tertiary Care Center

Laparoscopic ventral hernia repair reportedly yields lower postoperative complications than open repair. We hypothesized that patients undergoing laparoscopic repair would have lower postoperative infectious outcomes. Also, certain preoperative patient characteristics and preoperative hernia characteristics are hypothesized to increase complication risk in both groups. All ventral hernia repairs performed at University of Virginia from January 2004 to January 2006 were reviewed. Primary outcomes included wound healing complications and hernia recurrence. Categorical data were analyzed with χ2 and Fisher's exact tests. Continuous variables were evaluated with independent t tests and Mann-Whitney U tests. Multivariable logistic regression was performed. A total of 268 repairs (110 open, 158 laparoscopic) were evaluated. Patient and hernia characteristics were similar between groups, though the percents of wound contamination (5.4% vs 0.6%; P = 0.02) and simultaneous surgery (7.2% vs 0%; P = 0.001) were greater in the open procedures. Univariate analysis also revealed that open cases had a greater incidence of postoperative superficial surgical site infection (SSI) (30.0% vs 10.7%; P < 0.0001). Multivariable analysis revealed that both diabetes and open repair were associated with an increased risk of superficial SSI ( P = 0.019; odds ratio = 3.512; 95% confidence interval = 1.229–10.037 and P = 0.001; odds ratio = 4.6; 95% confidence interval = 1.9–11.2, respectively). Laparoscopic ventral hernia repair yielded lower rates of postoperative superficial SSI than open surgery. Other pre-operative patient characteristics and preoperative hernia characteristics, with the exception of diabetes, were not found to be associated with an increased risk of postoperative complications.