Assessment of mesh shrinkage using fibroblast-populated collagen matrices: a proof of concept for in vitro hernia mesh testing.

PURPOSE: This study uses free-floating contractile fibroblast-populated collagen matrices (FPCMs) to test the shrinkage of different hernia mesh products. We hope to present this model as a proof of concept for the development of in vitro hernia mesh testing-a novel technology with interesting potential. METHODS: FPCMs were formed by seeding Human Dermal Fibroblasts into collagen gels. FPCMs were seeded with three different cell densities and cast at a volume of 500 µl into 24-well plates. Five different mesh products were embedded within the collagen constructs. Gels were left to float freely within culture media and contract over 5 days. Photographs were taken daily and the area of the collagen gel and mesh were measured. Media samples were taken at days 2 and 4 for the purposes of measuring MMP-9 release. After 5 days, dehydrated FPCMs were also examined under light and fluorescence microscopy to assess cell morphology. RESULTS: Two mesh products-the mosquito net and large pore lightweight mesh were found to shrink notably more than others. This pattern persisted across all three cell densities. There were no appreciable differences observed in MMP-9 release between products. CONCLUSIONS: This study has successfully demonstrated that commercial mesh products can be successfully integrated into free-floating contractile FPCMs. Not only this, but FPCMs are capable of applying a contractile force upon those mesh products-eliciting different levels of contraction between mesh products. Such findings demonstrate this technique as a useful proof of concept for future development of in vitro hernia mesh testing.

The experimental methodology and comparators used for in vivo hernia mesh testing: a 10-year scoping review.

PURPOSE: Before being marketed, hernia mesh must undergo in vivo testing, which often includes biomechanical and histological assessment. Currently, there are no universal standards for this testing and methods vary greatly within the literature. A scoping review of relevant studies was undertaken to analyse the methodologies used for in vivo mesh testing. METHODS: Medline and Embase databases were searched for relevant studies. 513 articles were identified and 231 duplicates excluded. 126 papers were included after abstract and full text review. The data extraction was undertaken using standardised forms. RESULTS: Mesh is most commonly tested in rats (53%). 78% of studies involve the formation of a defect; in 52% of which the fascia is not opposed. The most common hernia models use mesh to bridge an acute defect (50%). Tensile strength testing is the commonest form of mechanical testing (63%). Testing strip widths and test speeds vary greatly (4-30 mm and 1.625-240 mm/min, respectively). There is little consensus on which units to use for tensile strength testing. Collagen is assessed for its abundance (54 studies) more than its alignment (18 studies). Alignment is not measured quantitatively. At least 21 histological scoring systems are used for in vivo mesh testing. CONCLUSIONS: The current practice of in vivo mesh testing lacks standardisation. There is significant inconsistency in every category of testing, both in methodology and comparators. We would call upon hernia organisations and materials testing institutions to discuss the need for a standardised approach to this field.

Computed tomography colonography: a new threat to the spleen?

We present a rare and previously undocumented potential complication of computed tomography (CT) colonography. CT colonography is a commonly performed investigation with a relatively low risk of complications. While splenic injury is a well-documented complication after colonoscopy, it has never been reported following CT colonography. A 64-year-old man presented with severe abdominal pain four hours after CT colonography. CT of his abdomen and pelvis revealed appearances consistent with intra-abdominal bleeding secondary to splenic injury. The patient immediately underwent an emergency laparotomy and splenectomy, revealing a grade III splenic capsular tear. Histological evaluation of splenic tissue showed normal morphology with no evidence of malignancy. While the aetiology of the patient's splenic injury remains uncertain, normal histopathology and the chronology of events represents an almost certain link to CT colonography.

A cadaveric study showing the anatomical variations in the branches of the dorsalis pedis artery at the level of the ankle joint and its clinical implication in ankle arthroscopy.

Introduction Pseudoaneurysm formation following ankle arthroscopy is a rare but potentially catastrophic complication. The placement of anterior ankle portals carries inherent risk to the superficial and deep peroneal nerves, as well as to the dorsalis pedis artery. Anatomical variations in the dorsalis pedis and the presence of branches at the joint line may increase the risk of vascular injury and pseudoaneurysm formation during arthroscopy. There is limited anatomical evidence available regarding the branches of the dorsalis pedis artery, which occur at the point at which they cross the ankle joint. Objectives The objective of the study was to describe the frequency and direction of branches of the dorsalis pedis crossing the ankle joint. Materials and Methods Nineteen cadaveric feet were carefully dissected to explore the course of the dorsalis pedis artery, noting in particular the branching pattern at the joint line. Results Eleven of the nineteen feet had a branch of the dorsalis pedis artery that crossed the level of the ankle joint. Out of these, six were lateral, four medial and one bilateral. Eight of the eleven specimens had one branch at, or just before, the level of the joint. Two specimens had two branches and one had three branches crossing the ankle, which were all in the same direction, crossing laterally to the main trunk of the dorsalis pedis. Conclusions Our study demonstrated high rates of branching of the dorsalis pedis artery at the level of the ankle joint. The role of these branches in pseudoaneurysm formation during anterior hindfoot surgery remains unclear.

Improving operation notes and postoperative care: an audit of current practice.

The operation note is the single most important document in surgical practice. Ninety one operation notes were assessed on their adherence to guidelines, as well as their legibility and ability to inform postoperative care; as judged by five different healthcare professionals. Results showed a deficiency in essential information and poor legibility overall. Re-audit of 103 operation notes after intervention showed an improvement in nearly all criteria measured. The results indicate that education about current guidelines and an increase in word processing of operation notes improves quality of documentation, and therefore of postoperative care.