No description available.

No description available.

No description available.

No description available.

No description available.

Methods: 40 patients with intermittent claudication (IC) and 40 healthy volunteers performed isometric ankle exercise or treadmill exercise to maximal walking distance (MWD). Lower limb pH was recorded during and for 1 hour after exercise. 7 patients with acute (ALI) and 24 patients with critical limb ischaemia (CLI) underwent lower limb anterior pH monitoring pre-and for 48 hours post lower limb surgical revascularisation. Platelet aggregation, markers of inflammation, endothelial and coagulation activation and urinary markers of renal tubular damage were assessed in all subjects. Results: There was a fall in intramuscular pH following both types of exercise in all test subjects. The magnitude of the changes was greatest in patients with IC. In patients with IC, treadmill exercise reduced platelet aggregation. This was accompanied by endothelial activation. Coagulation activation occurred in patients with IC following both forms of exercise. Baseline pH was lower in patients with ALI. Following surgical revascularisation, intra-muscular pH increased immediately in the patients with ALI. pH recovery was prolonged in patients with CLI. Coagulation activation and increased platelet aggregation were observed in the post-operative period. Conclusion: Platelet aggregation is reduced immediately following treadmill exercise to MWD. Surgical revascularisation resulted in a prothrombotic state despite the use of peri-operative heparin and aspirin. Intramuscular pH measurement may have a role in assessing the severity of exercise induced ischaemia. It is unlikely that peri-operative tissue pH monitoring will have a role in CLI. Further work focusing on patients with ALI is required.

No description available.

The aim of this study was to redesign a soft stabilisation prototype, for use in the treatment of low back pain. The prototype consisted of a stainless steel spinous process hook joined by two loops of polyester braid to two stainless steel laminar hooks. The ends of the loops of braid passed through a stainless steel sleeve, allowing the loops to be secured by crimping the sleeve with three crimp actions. Preliminary mechanical testing of the prototype device revealed a weakness in the design of the spinous process work. Mechanical testing of the looped braid indicated that reducing the number of crimp actions to one, would ensure that if the device was overloaded, it would fail by slippage of the braid through the sleeves, avoiding fracture of the hooks. Finite element analysis provided information on the theoretical stresses in the hooks. It was used to redesign the both the laminar and spinous process hooks in a titanium alloy (for MR compatibility) with a greater range of sizes. The redesigned soft stabilisation construct was tested according to the standard for testing spinal implants (ASTM F1717). These tests verified the successful redesign of the construct. While redesigning the soft stabilisation device, information on its attachment to the spine was sought. Literature surveys and mechanical testing revealed that the strength of the spinous process is around 400 N; about half that of the lamina. The mean angulation of the spinous process in the sagittal plane was found to be in the range 74-84° on patient radiographs. Further literature surveys showed that movement of an implant relative to bone should be avoided. A mechanical investigation revealed that appreciable movement between the spinous process hook and its site of attachment is unlikely. A spinal implant and surgical instruments were developed in compliance with the Medical Devices Directive.

No description available.

No description available.