Early and Long Term Outcomes Following Long Posterior Flap vs. Skew Flap for Below Knee Amputations.

OBJECTIVE: To compare outcomes between long posterior flap (LPF) and skew flap (SF) amputation over a 13 year period. METHODS: This was a retrospective observational cohort study. Consecutive patients undergoing a LPF or SF below knee amputation (BKA) over a 13 year period at one hospital were identified. Both techniques were performed regularly, depending on tissue loss and surgeon preference. The primary outcome was surgical revision of any kind. Secondary outcomes included revision to above knee amputation (AKA), length of hospital stay (LOS), and mortality. A smaller cohort of patients who were alive and unilateral below knee amputees were contacted to ascertain prosthetic use and functional status. RESULTS: In total, 242 BKAs were performed in 212 patients (125 LPF and 117 SF; median follow up 25.8 months). Outcomes for the two groups were equivalent for surgical revision of any kind (27 LPF vs. 31 SF; p = .37), revision to an AKA (18 LPF vs. 14 SF; p = .58), LOS (29 days for LPF vs. 28 days for SF; p = .83), and median survival (23.9 months for LPF vs. 28.8 months for SF; p = .89). Multivariable analysis found amputation type had no effect on any outcome. Functional scores from a smaller cohort of 40 unilateral amputees who were contactable demonstrated improved outcomes with the LPF vs. the SF (p = .038). CONCLUSION: Both techniques appear equivalent for rates of surgical residual limb failure. Functional outcomes may be better with the LPF.

Application of Targeted Molecular and Material Property Optimization to Bacterial Attachment-Resistant (Meth)acrylate Polymers.

Developing medical devices that resist bacterial attachment and subsequent biofilm formation is highly desirable. In this paper, we report the optimization of the molecular structure and thus material properties of a range of (meth)acrylate copolymers which contain monomers reported to deliver bacterial resistance to surfaces. This optimization allows such monomers to be employed within novel coatings to reduce bacterial attachment to silicone urinary catheters. We show that the flexibility of copolymers can be tuned to match that of the silicone catheter substrate, by copolymerizing these polymers with a lower Tg monomer such that it passes the flexing fatigue tests as coatings upon catheters, that the homopolymers failed. Furthermore, the Tg values of the copolymers are shown to be readily estimated by the Fox equation. The bacterial resistance performance of these copolymers were typically found to be better than the neat silicone or a commercial silver containing hydrogel surface, when the monomer feed contained only 25 v% of the "hit" monomer. The method of initiation (either photo or thermal) was shown not to affect the bacterial resistance of the copolymers. Optimized synthesis conditions to ensure that the correct copolymer composition and to prevent the onset of gelation are detailed.

Intradural lipoma at the foramen magnum presenting with classical Chiari symptoms: A case report.

Intradural lipomas are rare lesions, usually associated with spinal dysraphism, affecting the spinal cord. Intracranial lipomas make up less than 1% of intracranial tumours; only 13 cases of these lesions being located at the craniocervical junction are reported in the literature. These lesions tend to present with neurological deficits such as quadraparesis and incontinence. We present the first case of a successfully treated intradural lipoma at the foramen magnum in a 15-year-old girl who presented with classical Chiari symptoms and no neurological deficits.

A potential alternative to fungicides using actives-free (meth)acrylate polymers for protection of wheat crops from fungal attachment and infection.

Fungicidal compounds are actives widely used for crop protection from fungal infection, but they can also kill beneficial organisms, enter the food chain and promote resistant pathogen strains from overuse. Here we report the first field crop trial of homopolymer materials that prevent fungal attachment, showing successful crop protection via an actives-free approach. In the trial, formulations containing two candidate polymers were applied to young wheat plants that were subject to natural infection with the wheat pathogen Zymoseptoria tritici. A formulation containing one of the candidate polymers, poly(di(ethylene glycol) ethyl ether acrylate) (abbreviated DEGEEA), produced a significant reduction (26%) in infection of the crop by Z. tritici, delivering protection against fungal infection that compared favourably with three different commercially established fungicide programmes tested in parallel. Furthermore, the sprayed polymers did not negatively affect wheat growth. The two lead polymer candidates were initially identified by bio-performance testing using in vitro microplate- and leaf-based assays and were taken forward successfully into a programme to optimize and scale-up their synthesis and compound them into a spray formulation. Therefore, the positive field trial outcome has also established the validity of the smaller-scale, laboratory-based bioassay data and scale-up methodologies used. Because fungal attachment to plant surfaces is a first step in many crop infections, this non-eluting polymer: (i) now offers significant potential to deliver protection against fungal attack, while (ii) addressing the fourth and aligning with the eleventh principles of green chemistry by using chemical products designed to preserve efficacy of function while reducing toxicity. A future focus should be to develop the material properties for this and other applications including other fungal pathogens.

Screening of Oligomeric (Meth)acrylate Vaccine Adjuvants Synthesized via Catalytic Chain Transfer Polymerization.

This report details the first systematic screening of free-radical-produced methacrylate oligomer reaction mixtures as alternative vaccine adjuvant components to replace the current benchmark compound squalene, which is unsustainably sourced from shark livers. Homo-/co-oligomer mixtures of methyl, butyl, lauryl, and stearyl methacrylate were successfully synthesized using catalytic chain transfer control, where the use of microwave heating was shown to promote propagation over chain transfer. Controlling the mixture material properties allowed the correct viscosity to be achieved, enabling the mixtures to be effectively used in vaccine formulations. Emulsions of selected oligomers stimulated comparable cytokine levels to squalene emulsion when incubated with human whole blood and elicited an antigen-specific cellular immune response when administered with an inactivated influenza vaccine, indicating the potential utility of the compounds as vaccine adjuvant components. Furthermore, the oligomers' molecular sizes were demonstrated to be large enough to enable greater emulsion stability than squalene, especially at high temperatures, but are predicted to be small enough to allow for rapid clearance from the body.

Developing Echogenic Materials as Catheters for Use with Ultrasound.

Patients with peripherally inserted central catheters (PICCs) are routinely discharged with the catheters in place. These patients experience complications due to undetected thrombosis or accidental dislodgement, with tracking through limited X-ray imaging. Developing catheters with the capability to be tracked without the need for X-ray imaging would greatly benefit these patients by decreasing patient stress, reducing time to diagnosis, and increasing nursing home capabilities. This study reports on the incorporation of echogenic microspheres into catheters to produce bulk echogenic effects for developments in the field of real-time ultrasound tracking of polymeric medical devices. The impact on elastic modulus, ultrasound contrast, and cytocompatibility of the polymer was analyzed when incorporating up to 10 wt % glass microspheres. Up to this loading level, the elastic modulus was found to remain constant. However, at 10 wt %, extrusion defects due to agglomeration, air bubbles, and shearing were numerous and deemed detrimental to ultrasound imaging. Successful, defect-free samples were produced with 5 wt % microsphere loading and when embedded in a soft tissue phantom revealed a significant increase in the signal-to-noise ratio as compared to the polymer alone. Preliminary results have shown a successful increase in polymer's echogenic properties, without undermining its mechanical and cytocompatibility properties.

Facile Synthesis of Functionalised Hyperbranched Polymers for Application as Novel, Low Viscosity Lubricant Formulation Components.

A novel, previously unreported, method for synthesising hyperbranched (HB) materials is detailed. Their use as additives to produce lubricant formulations that exhibit enhanced levels of wear protection and improved low-temperature oil viscosity and flow is also reported. The lubricant formulations containing HB additives were found to exhibit both significantly lower viscosities and improved in-use film-forming properties than the current industry standard formulations. To achieve this, alkyl methacrylate oligomers (predominantly dimers and trimers) were synthesised using catalytic chain transfer polymerisation. These were then used as functional chain transfer agents (CTA) to control the polymerisation of divinyl benzene (DVB) monomers to generate highly soluble, high polydispersity HB polymers. The level of dimer/trimer purification applied was varied to define its influence on both these HB resultant structures and the resultant HB additives' performance as a lubricant additive. It was shown that, while the DVB acted as the backbone of the HB, the base oil solubility of the additive was imparted by the presence of the alkyl chains included in the structure via the use of the oligomeric CTAs.

Systematic Review and Meta-Regression of Factors Affecting Midline Incisional Hernia Rates: Analysis of 14,618 Patients.

BACKGROUND: The incidence of incisional hernias (IHs) following midline abdominal incisions is difficult to estimate. Furthermore recent analyses have reported inconsistent findings on the superiority of absorbable versus non-absorbable sutures. OBJECTIVE: To estimate the mean IH rate following midline laparotomy from the published literature, to identify variables that predict IH rates and to analyse whether the type of suture (absorbable versus non-absorbable) affects IH rates. METHODS: We undertook a systematic review according to PRISMA guidelines. We sought randomised trials and observational studies including patients undergoing midline incisions with standard suture closure. Papers describing two or more arms suitable for inclusion had data abstracted independently for each arm. RESULTS: Fifty-six papers, describing 83 separate groups comprising 14,618 patients, met the inclusion criteria. The prevalence of IHs after midline incision was 12.8% (range: 0 to 35.6%) at a weighted mean of 23.7 months. The estimated risk of undergoing IH repair after midline laparotomy was 5.2%. Two meta-regression analyses (A and B) each identified seven characteristics associated with increased IH rate: one patient variable (higher age), two surgical variables (surgery for AAA and either surgery for obesity surgery (model A) or using an upper midline incision (model B)), two inclusion criteria (including patients with previous laparotomies and those with previous IHs), and two circumstantial variables (later year of publication and specifying an exact significance level). There was no significant difference in IH rate between absorbable and non-absorbable sutures either alone or in conjunction with either regression analysis. CONCLUSIONS: The IH rate estimated by pooling the published literature is 12.8% after about two years. Seven factors account for the large variation in IH rates across groups. However there is no evidence that suture type has an intrinsic effect on IH rates.