Leslie Klenerman

Systemic and local effects of the application of a tourniquet

The effect of the application of a tourniquet to a limb and the release of the accumulated metabolites have been investigated with reference to the acid-base level in the blood from the limb and in the right atrium. Investigations have been carried out experimentally in rhesus monkeys and observations have been made on patients undergoing reconstructive operations on the knee. The acidotic blood from the ischaemic limb produces little systemic effect. The limb recovers in approximately 40 minutes after a tourniquet has been in place for four hours. Three hours is recommended as a reasonable upper limit for the safe application of a pneumatic tourniquet.

An application of the fear avoidance model to three chronic pain problems.

The Fear Avoidance Model of Exaggerated Pain Perception was developed in an attempt to explain how, and why, some individuals develop a more substantial psychological overlay to their low back pain problem than do others. The present paper describes a study in which three chronic pain groups, consisting of Post-Herpetic neuralgia patients, Reflex Sympathetic Dystrophy patients and chronic low back pain patients were compared with three pain-free comparison groups using the Fear Avoidance Model of Exaggerated Pain Perception. The results show statistically significant differences between the chronic groups and the recovered comparison groups. These results demonstrate the usefulness of the Fear Avoidance Model as an explanation of psychological overlay in chronic pain conditions regardless of pathology.

Investigation of Muscle Imbalance in the Leg in Symptomatic Forefoot Pes Cavus: A Multidisciplinary Study

The cross-sectional areas of the peroneal and anterior muscle compartments at the same level in the upper leg were measured using magnetic resonance imaging in 41 cases of forefoot pes cavus. The pes cavus group included idiopathic cases and pes cavus associated with Charcot-Marie-Tooth disease, Friedreichs ataxia, cerebral palsy, status postpoliomyelitis, nerve trauma, and spinal cord tethering. Thirty-nine of these cases were symptomatic. The results were compared with studies of 11 normal controls. It was found that in the majority of cases of forefoot cavus, the peroneal compartment was enlarged relative to the anterior compartment when compared with the normal controls. Biopsies of the tibialis anterior and peroneus longus muscles in 18 patients with forefoot pes cavus showed that any relative expansion of the peroneus longus was not due to pseudohypertrophy. Overaction of the peroneus longus in comparison to its antagonist the tibialis anterior is proposed as an important factor in the pathogenesis of the majority of symptomatic cases of forefoot pes cavus.

The Effect of Pneumatic Tourniquets on Skeletal Muscle Physiology

The effect of 3- and 5-hour pneumatic tourniquets on skeletal muscle physiology was investigated. Maximum isometric tension development, contraction and half relaxation times were measured in the muscles lying immediately under and distal to the tourniquet. On release of the tourniquet no consistent difference between control and experimental muscles was observed with respect to contraction and half relaxation times; however, there was a marked reduction in maximum isometric tension development. On the sixth day after release of a 5-hour tourniquet, isometric tension was reduced to 2--20 per cent of the control value in the distal muscle and to 40--60 per cent of the control value in the compressed muscle. Six days after a 3-hour tourniquet the compressed muscle tension was reduced to approximately 80 per cent of the control value whilst in the distal muscle, tension development varied from normal to 64 per cent of the control value. Thus it is shown that the effect on muscle contraction after a 3-hour tourniquet is not immediately reversed by the restoration of the blood supply. A reduction in muscle strength follows which may take a week or more to recover.

Decreased radial bone mass in Codes' fracture

Computed tomography measurements on the radii of 18 women with Colles fracture of the radius have shown that compared to normal women of the same age they tended to have a smaller bone cross-sectional area in the radius midshaft, a small deficit of cortical bone, and a substantial deficit of trabecular bone in the distal radius.

Ischemia-reperfusion-induced muscle damage. Protective effect of corticosteroids and antioxidants in rabbits.

We examined the potential protective effect of pretreatment with corticosteroids or antioxidants (ascorbic acid or allopurinol) in rabbits with reperfusion-induced damage to skeletal muscle after ischemia. 4 hours of limb ischemia induced by a pneumatic tourniquet, followed by reperfusion for 1 hour, caused a considerable amount of ultrastructural damage to the anterior tibialis muscles accompanied by a rise in circulating creatine kinase activity. Pretreatment of animals with depomedrone by a single 8 mg bolus injection led to a preservation of the anterior tibialis structure on both light and electron microscopy. High-dose continuous intravenous infusion with ascorbic acid (80 mg/hr) throughout the period of ischemia and reperfusion also preserved skeletal muscle structure, although allopurinol in various doses had no protective effect. These data are fully compatible with a mechanism of ischemia/reperfusion-induced injury to skeletal muscle, involving generation of oxygen radicals and neutrophil sequestration and activation. They also indicate that damage to human skeletal muscle caused by prolonged use of a tourniquet is likely to be reduced by simple pharmacological interventions.

Ischaemic preconditioning of skeletal muscle: 2. INVESTIGATION OF THE POTENTIAL MECHANISMS INVOLVED

We have previously shown that prior exposure of rat hind limbs to ischaemia for five minutes and reperfusion for five minutes reduced the structural damage to skeletal muscle which followed a subsequent period of ischaemia for four hours and reperfusion for one hour. We have now examined the potential mechanisms by which this ischaemic preconditioning protocol may be effective in reducing damage to skeletal muscle induced by prolonged ischaemia and reperfusion. Prior exposure of the hindlimb to ischaemia for five minutes and reperfusion for five minutes did not prevent the fall in the ATP content of tibialis anterior which occurred after a subsequent period of ischaemia for four hours and reperfusion for one hour. Similarly, no effect of the preconditioning protocol was seen on the elevated muscle myeloperoxidase, indicative of an elevated neutrophil content, or abnormal muscle cation content. Reperfused ischaemic muscle was also found to have an increased content of heat-shock protein (HSP) 72, but the preconditioning protocol did not further increase the content of this or other HSPs indicating that it was not acting by increasing the expression of these cytoprotective proteins. The protective effects of preconditioning appeared to be mimicked by the infusion of adenosine to animals immediately before exposure to the four-hour period, indicating a potential mechanism by which skeletal muscle may be preconditioned to maintain structural viability.

Dantrolene sodium protects against experimental ischemia and reperfusion damage to skeletal muscle

The effect of 4 hours of ischemia followed by reperfusion for 1 hour has been studied in fully anesthetized rabbits. Muscles from the limb subjected to ischemia and reperfusion showed considerable ultrastructural damage, although the distribution of damage between muscles was not uniform (anterior tibialis > soleus > quadriceps). Damage to the muscle was associated with a significant increase in the concentration of some indicators of free radical-mediated processes (thiobarbituric acid-reactive substances and diene conjugates), although others (glutathione and protein sulfhydryl groups) were unchanged. Reperfused muscles also showed considerable changes in their calcium and sodium contents. Treatment of animals with dantrolene sodium (4 mg/hr) throughout the periods of ischemia and reperfusion was found to preserve the ultrastructural appearance of quadriceps, soleus and anterior tibialis muscles. No effect of dantrolene sodium on indicators of free radical activity or muscle cation content was seen.

The Jaipur foot

The Jaipur foot was developed for barefoot amputees by Professor P. K. Sethi. He used local artisans and readily available materials. The prosthesis was cheap and could be made in one hour. It enabled amputees to work in rural conditions, muddy and wet fields and to climb trees. It has been widely used in India, South East Asia and Africa, where local variations to the design have now been made.

Ischaemic preconditioning of skeletal muscle

We have previously shown that prior exposure of rat hind limbs to ischaemia for five minutes and reperfusion for five minutes reduced the structural damage to skeletal muscle which followed a subsequent period of ischaemia for four hours and reperfusion for one hour. We have now examined the potential mechanisms by which this ischaemic preconditioning protocol may be effective in reducing damage to skeletal muscle induced by prolonged ischaemia and reperfusion. Prior exposure of the hindlimb to ischaemia for five minutes and reperfusion for five minutes did not prevent the fall in the ATP content of tibialis anterior which occurred after a subsequent period of ischaemia for four hours and reperfusion for one hour. Similarly, no effect of the preconditioning protocol was seen on the elevated muscle myeloperoxidase, indicative of an elevated neutrophil content, or abnormal muscle cation content. Reperfused ischaemic muscle was also found to have an increased content of heat-shock protein (HSP) 72, but the preconditioning protocol did not further increase the content of this or other HSPs indicating that it was not acting by increasing the expression of these cytoprotective proteins. The protective effects of preconditioning appeared to be mimicked by the infusion of adenosine to animals immediately before exposure to the four-hour period, indicating a potential mechanism by which skeletal muscle may be preconditioned to maintain structural viability.