Study of tractional force for various pelvic reconstructive graft materials - an experimental animal model

[Extract] Hypothesis / aims of study: To compare tensile strengths of three different types of mesh used in pelvic reconstruction surgery at different stages of healing and evaluate the extent of tissue integration at each stage. Study design, materials and methods: Forty five female Wistar rats were subcutaneously implanted with one of three types of mesh, elastic low density monofilament polypropylene mesh (high friction arm of MonarcTM suburethral sling), soft monofilament polypropylene mesh (PerigeeTM, AMS), and SIS porcine mesh (Surgisis, Cook Medical). Tensile strength was tested at days 10, 19, 25, 33 and 40 by mobilising the meshes using a dynamometer. The meshes and overlying tissue were histologically examined for tissue integration using the parameters inflammatory response, degree of fibrous tissue formation and collagen deposition. Results; We found an essentially linear increase in tensile strength over 40 days in both polypropylene meshes, the highest being an average of 19.385 N at Day 40. The high friction arm mesh had higher tensile strength at Days 19 and 25 of the study compared to the soft section of polypropylene mesh. There was no appreciable difference between the two at Day 40. There was a significantly lower tensile strength in the SIS mesh across all stages of healing, with no increase in strength over time. This mesh from Day 25 onwards was unable to be separated in one piece from the tissue. Concluding message: The high friction arm of the MonarcTM mesh had higher tensile strength earlier then the soft polypropylene mesh of PerigeeTM. But there was no difference in both meshes by day 40 and both had higher tensile strengths than the SIS. The SIS mesh separation point was within the mesh, rather than between the mesh-tissue interfaces, suggesting stronger tissue integration than internal mesh strength

A comparison of videolaryngoscopy using standard blades or non-standard blades in children in the Paediatric Difficult Intubation Registry

Background: The design of a videolaryngoscope blade may affect its efficacy. We classified videolaryngoscope blades as standard and non-standard shapes to compare their efficacy performing tracheal intubation in children enrolled in the Paediatric Difficult Intubation Registry. Methods: Cases entered in the Registry from March 2017 to January 2020 were analysed. We compared the success rates of initial and eventual tracheal intubation, complications, and technical difficulties between the two groups and by weight stratification. Results: Videolaryngoscopy was used in 1313 patients. Standard and non-standard blades were used in 529 and 740 patients, respectively. Both types were used in 44 patients. In children weighing <5 kg, standard blades had significantly greater success than non-standard blades at initial (51% vs 26%, P=0.002) and eventual (81% vs 58%, P=0.002) attempts at tracheal intubation. In multivariable logistic regression analysis, standard blades had 3-fold greater odds of success at initial tracheal intubations compared with non-standard blades (adjusted odds ratio 3.0, 95% confidence interval): 1.32–6.86, P=0.0009). Standard blades had 2.6-fold greater odds of success at eventual tracheal intubation compared with non-standard blades in children weighing <5 kg (adjusted odds ratio 2.6, 95% confidence interval: 1.08–6.25, P=0.033). There was no significant difference found in children weighing ≥5 kg. Conclusions: In infants weighing <5 kg, videolaryngoscopy with standard blades was associated with a significantly greater success rate than videolaryngoscopy with non-standard blades. Videolaryngoscopy with a standard blade is a sensible choice for tracheal intubation in children who weigh <5 kg