Mapping service development: A comparison of UK and US studies

Introduction

Reasons for differences in the effect sizes of studies on complex interventions, such as assertive outreach, between the US and the UK are a much debated topic. One possible explanation was suggested to be the potentially different quality of standard care in the two countries.

Aims

We aimed to

Methods

We conducted a systematic review and meta-analysis of RCTs conducted in the UK or the US

Results

The Risk Ratios for relapse/readmission were very similar and favouring experimental treatment both in the UK (RR 0.80, CI 0.73–0.88) and the US (RR 0.87, CI 0.79–0.95). The development of effects resulting from experimental interventions relative to those from TAU over time shows a slightly different pattern for the two countries.

Conclusions

The broadly similar total RR for relapse/readmission in both countries confirms the comparability of studies conducted in the UK and the US and suggests no significant overall difference in the quality of standard care. The chronological development of effects, however, reflects developments in TAU over time which differ between the two countries.

Comparison of three separate antiadhesive barriers for intraperitoneal onlay mesh hernia repair in an experimental model

Background

Adhesion formation is a common adverse effect in intraperitoneal onlay mesh (IPOM) surgery. Different methods of adhesion prevention have been developed, including coated meshes and separate antiadhesive barriers (SABs). In this study one type of mesh was tested with different SABs, which were fixed to the sutured mesh using fibrin sealant. The primary aim was to compare adhesion prevention between different SABs. Secondary aims were the assessment of tissue integration and evaluation of SAB fixation with fibrin sealant.

Methods

Thirty-two rats were randomized to one of three treatment groups (SurgiWrap®, Prevadh® and Seprafilm®) or a control group (no SAB). Animals were operated on with an open IPOM technique (8 per group). One macroporous polypropylene mesh per animal (2 × 2 cm) was fixed with four non-absorbable sutures. An antiadhesive barrier of 2·5 × 2·5 cm was fixed with fibrin sealant. After 30 days, adhesion formation, tissue integration, seroma formation, inflammation and vascularization were evaluated macroscopically and by histology.

Results

Prevadh® and Seprafilm® groups showed a significant reduction in adhesion formation compared with the control group. Tissue integration of the mesh was reduced in these groups. Fibrin sealant fixed the SAB to the mesh securely in all groups.

Conclusion

Prevadh® and Seprafilm® are potent materials for the reduction of adhesion formation. A potential relationship between effective adhesion prevention and impaired tissue integration of the implant was observed. Fibrin sealant proved an excellent agent for SAB fixation.

Differential protein levels and post-translational modifications in spinal cord injury of the rat

Although changes in protein expression in spinal cord injury (SCI) would be of pivotal interest, information so far is limited. It was therefore the aim of the study to determine protein levels and post-translational modifications in the early phase following SCI in the rat. SCI was induced in Sprague-Dawley rats and sham operated rats served as controls. A gel-based proteomic approach using two-dimensional gel electrophoresis followed by quantification with specific software and subsequent identification of differentially expressed proteins by nano-ESI-LC-MS/MS was applied. Proteins of several pathways and cascades were dysregulated in SCI: 14-3-3 epsilon protein, dynein light chain 1, and tubulin beta-5 chain showed higher levels in SCI, whereas adenylyl cyclase associated protein 1, dihydropyrimidinase-related protein 2, F-actin capping protein subunit beta, glyceraldehyde-3-phosphate dehydrogenase, stress-induced phosphoprotein 1 and transthyretin showed lower levels in the injured tissue. Post-translational modifications indicated free oxygen radical attack on proteins in SCI. The occurrence of stress is indicated by deranged stress-induced phosphoprotein 1 and signaling abnormalities are reflected by adenylyl cyclase-associated protein 1 and 14-3-3 epsilon protein. The findings propose the involvement of the corresponding cascades and challenge further work into aberrant signaling and oxidative stress in SCI, which may form the basis for experimental intervention for spinal cord trauma.

Fibrin sealant (Tissucol) enhances tissue integration of condensed polytetrafluoroethylene meshes and reduces early adhesion formation in experimental intraabdominal peritoneal onlay mesh repair

BACKGROUND

The laparoscopic intraabdominal peritoneal onlay mesh repair (IPOM) is a common technique for the reinforcement of multiple ventral hernias or defined defects after laparotomies. However, the placement of synthetic meshes in the intraabdominal cavity can be associated with severe complications. Adhesions frequently originate from the implant and protruding parts of fixation devices, presenting a serious clinical problem with potentially detrimental consequences. This study was designed to assess the impact of fibrin sealing with Tissucol (FS; Baxter, Vienna, Austria) on adhesion formation to condensed polytetrafluoroethylene meshes (Motif Meshes, MM; Proxy Biomedical, Galway, Ireland) as well as on tissue integration of these implants in experimental IPOM repair in rats. It was tested whether FS application allowed the reduction of sutures for mesh fixation without increasing the risk of mesh dislocation.

MATERIALS AND METHODS

Sixteen rats were assigned to the implantation of MM with four nonresorbable sutures (Synthofil; Ethicon, Norderstedt, Germany) with additional fibrin coating with 0.2 mL FS or to MM fixation with six nonresorbable sutures without FS (n = 8 per group). MM with 2 cm in diameter were implanted in open IPOM by a laparatomy. The observation period of 17 days ensured assessment of adhesions after the full degradation of FS. Adhesions were rated with the score suggested by Vandendael. Histology was performed.

RESULTS

All eight MMs without FS sealing elicited severe (grade III) adhesions, whereas fibrin-sealed MM were rated mild in 1, moderate in 5, and severe in 2 cases. The superior finding in the FS group was statistically significant. Impaired integration of sutured-only MM was observed in four cases, whereas all FS-sealed MM were well integrated.

CONCLUSIONS

FS improves the tissue integration, reduces early adhesion formation to cPTFE implants, and allows reduction of perforating fixation devices in experimental IPOM repair.

Adverse effects associated with the use of porcine cross-linked collagen implants in an experimental model of incisional hernia repair

BACKGROUND

Porcine cross-linked collagen (PermaCol, PCL; TSL, Aldershot, United Kingdom) has been proposed as permanent biomaterial in incisional hernia repair. We evaluated the biocompatibility of PCL in an established animal model.

MATERIAL AND METHODS

In 10 Sprague Dawley rats, two hernias per animal were created in the abdominal wall left and right of the linea alba (1.5 cm in diameter), and the peritoneum was spared. The lesions were left untreated for 10 days, until incisional hernias developed. These defects were covered with non-perforated (out-of-the-box, n = 12) or perforated (modified; n = 8) PCL (2 x 2 cm). In a first step, 12 non-perforated implants were tested in a short-term observation period of 17 days. Eight of these non-perforated implants were fibrin sealed (0.3 mL, Tissucol; Baxter, Vienna, Austria), whereas four non-perforated implants were sutured with non-resorbable material. In a second step, perforations were added as modification to PCL to facilitate drainage of fluids, cell ingrowth, and transgression of fibrin sealant. All perforated implants were fibrin sealed and included in a long-term observation period of 3 months. The observation periods allowed the evaluation of the complete degradation of the fibrin sealant fixation after 2 weeks and of the implant integration in a chronic timeframe. Implant sites were analyzed macroscopically and histologically.

RESULTS

All PCL samples elicited strong local inflammation with signs of foreign body reaction. Integration of perforated PCL appeared limited after 3 months. Three animals had to be euthanized prior to intended time points because of transcutaneous migration of implants.

CONCLUSIONS

In an experimental model of incisional hernia repair, PCL does not integrate well in the abdominal wall and shows poor biocompatibility.

Cyanoacrylate tissue sealant impairs tissue integration of macroporous mesh in experimental hernia repair

BACKGROUND

Tissue sealants have been proposed as an alternative to permanent fixation devices in hernia repair with the aim of reducing perforation-associated complications and chronic pain. Sealants can be divided into three main categories: synthetic glues (e.g., cyanoacrylate based), biologic products (e.g., fibrin sealant), and genetically engineered polymer protein glues. The beneficial effects of fibrin sealant have been reported in both experimental and clinical hernia repair. However, data on cyanoacrylate glues for mesh sealing are limited.

METHODS

In 20 Sprague-Dawley rats, two hernia defects (1.5 cm in diameter) per animal were created bilaterally in the midline of the abdominal wall. The peritoneum was spared. The lesions were left untreated for 10 days to achieve a chronic condition. Defects then were covered with TI-Mesh xl (2 x 2 cm), which was glued with Glubran-II. The time points of sacrifice were 17 days, 28 days, and 3 months. At autopsy, meshes were biomechanically tested, and histology was performed.

RESULTS

Tissue integration of the meshes was impaired at all time points by impenetrable glue plaques. At application sites, the elasticity of the abdominal wall was significantly reduced because of nonresorbed, rigid glue residues.

CONCLUSIONS

Mesh fixation by Glubran-II impairs tissue integration, elicits inflammation, and unfavorably alters the biomechanics of macroporous mesh and the abdominal wall.

Adverse effects of porcine small intestine submucosa implants in experimental ventral hernia repair

BACKGROUND

Biomeshes made of porcine small intestine submucosa (SIS) have recently been suggested for repair of ventral hernia. A fully biodegradable combination of implant and fibrin sealant fixation was assessed in a new rat model with sutures serving as control.

METHODS

In 10 Sprague-Dawley rats, two defects per animal were created in the abdominal wall left and right of the linea alba (1 cm in diameter), and the peritoneum was spared. The lesions were left untreated for 10 days to achieve a chronic condition and were then covered with SIS (2 x 2 cm), sealed or sutured (n = 10 per group). Randomization allowed sealant and sutures in one animal. Animals were killed on postoperative day 17, and implant sites were analyzed macroscopically, histologically, and microbiologically.

RESULTS

Abscedation, encapsulation, and putrid seroma were observed in all samples, regardless of fixation technique. Histology revealed lytic necrosis and extensive inflammatory response of the surrounding tissue. Tissue samples obtained from three implant sites were positive for beta-hemolytic Streptococcus. SIS was not detectable after 17 days.

CONCLUSIONS

Adverse effects were observed using SIS in an experimental model of ventral hernia and were not linked to fixation method or study design. Further experimental investigations on SIS are necessary before its clinical use in hernia repair.