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Biomedical subjects

T E Hems

Publications and source records attributed to T E Hems.

15 recordsLinked to original sources

Repairing spinal roots after brachial plexus injuries.

The problems of repairing spinal roots after brachial plexus avulsion injuries are discussed in the light of current surgical diagnosis and treatment. An advancing understanding of the cellular mechanisms of nerve regeneration and progress in surgical technology indicates a possibility for the repair at least of ventral roots with grafts which may be of neural or non-neural origin. Enhancement of the regenerative properties may further be made possible by the application of neurotrophic factors at the repair site or centrally. The short and long-term implications of current research into these methods are discussed.

Brachial Plexus

Repair of avulsed cervical nerve roots. An experimental study in sheep.

An experimental model was established to investigate the possibility of repairing cervical nerve roots avulsed from the spinal cord, as occurs in traction injuries of the brachial plexus. In five sheep the C6 root was avulsed and the ventral root was reattached using freeze-thawed muscle as a short graft (0.5 cm). Recovery was assessed after one year by electrophysiology and histology. Stimulation of the root produced muscle contractions in four out of five sheep. Action potentials were recorded distal to the grafts in all five sheep. Histological examination showed regenerated fibres in the ventral roots in all cases. These fibres could be traced distally to the brachial plexus. Our study confirms that motor fibres can regenerate out of the spinal cord into the ventral roots and reinnervate muscles, and suggests that reimplantation of avulsed roots is a surgical option in selected cases of traction injury of the brachial plexus.

Action Potentials

The limit of graft length in the experimental use of muscle grafts for nerve repair.

In order to investigate whether there is any length limit for the success of freeze-thawed muscle grafts when used for peripheral nerve repair, an experimental study was undertaken in the rabbit. Previous work has shown 4 cm muscle grafts in the rabbit sciatic nerve to be successful. On this basis 5 cm and 10 cm muscle grafts were inserted into the common peroneal nerve and compared with 5 cm and 10 cm free nerve grafts. Recovery was assessed after 250 days using whole nerve physiology, weights of innervated muscles, and histological examination of the nerve. At both 5 cm and 10 cm the nerve grafts performed significantly better than the muscle grafts, the 10 cm muscle grafts being totally ineffective. The implications of these results for the application of freeze-thawed muscle grafting in peripheral nerve surgery and the possible factors limiting length of grafting are discussed.

Animals

Basil Kilvington. Unknown pioneer of peripheral nerve repair.

In the early years of the present century, a group of experiments assessing the results of the surgical repair of peripheral nerves and spinal roots was performed by Basil Kilvington. The outcome of the experiments was assessed using both electrophysiological and morphological techniques. Much of Kilvington's work remained unrecognized and was thus repeated at a later date. Kilvington's role in the early history of the surgical repair of nerves appears to have been forgotten and his substantial and prophetic discoveries deserve better recognition.

Australia

The use of coaxially aligned freeze-thawed skeletal muscle autografts in the repair of the cauda equina--in the sheep.

The aim was to develop a model for study of nerve regeneration in nerve roots above the level of the dorsal root ganglion and to investigate the use of freeze-thawed muscle autografts for repair of nerve roots at this level. Four adult sheep were used for the experiment. A laminectomy was performed at the lumbosacral junction and the S2 root identified. Both the dorsal and ventral S2 roots were divided unilaterally within the dura and a freeze-thawed muscle graft was inserted into the nerve gap. When assessed at 6 months an action potential was recordable from the ventral root in one sheep. Histological examination of the nerve roots showed evidence of regeneration across the graft in the ventral roots of all the sheep and the dorsal roots of some. This preliminary work indicates a capacity for regeneration of the cauda equina and that freeze-thawed muscle can support this. It provides a useful model for further study of nerve root repair.

Animals

Comparison of different methods of repair of long peripheral nerve defects: an experimental study.

In order to compare the performance of free nerve grafts, vascularised nerve grafts, and freeze-thawed muscle autografts for the repair of long nerve defects an experimental study was undertaken in the rabbit peroneal nerve. 5 cm defects were repaired using each method. Recovery of function was assessed after 250 days using sensory and motor physiology, and histological examination of the nerve. Reliable recovery occurred with both types of nerve graft but not with muscle grafts. Vascularised nerve grafts performed better than free nerve grafts on all parameters measured but this only reached statistical significance for sensory receptive areas and myelinated fibre diameters distal to the grafts. The role of each method of repair in peripheral nerve surgery is reviewed.

Animals

Freeze-thawed skeletal muscle autografts used for brachial plexus repair in the non-human primate.

An experimental study undertaken in the marmoset is reported. A defect in the lateral cord of the brachial plexus was repaired with a longitudinally aligned freeze-thawed skeletal muscle autograft. Recovery was assessed after one year using sensory and motor electrophysiological and also histological examination of the nerve. The results show that this is a satisfactory method of peripheral nerve repair in the marmoset. It is suggested that the technique may be applicable to repair of the human brachial plexus.

Animals

Prevention of hand injuries in cycle accidents.

More than one fifth of patients in a group involved in cycle crashes sustained hand injuries. The average time off work as a result of the hand injury in our study was 17.6 days. The number and severity of hand injuries would be reduced by the wearing of proper gloves and this is recommended. The gloves currently sold as "cycling" gloves are not adequate.

Abbreviated Injury Scale

Repair of cervical nerve roots proximal to the root ganglia. An experimental study in sheep.

An experimental model was established to investigate the possibility of repairing cervical nerve roots damaged above the dorsal root ganglion, as occurs in traction injuries of the brachial plexus. In four sheep the C6 root was divided and repaired within the dura using freeze-thawed muscle grafts. Recovery was assessed after eight months by electrophysiology and histology. Action potentials were recorded distal to the grafts in all four sheep, indicating regeneration of motor fibres. Histological examination showed regenerated fibres in the ventral roots below the grafts in all cases. These fibres could be traced distally to the brachial plexus. There was no evidence of recovery of dorsal roots.

Action Potentials

Cosmetic surgery for Cornelia de Lange syndrome.

A case of Cornelia de Lange syndrome is presented in which modern plastic surgery was used to reduce excessive facial hair. Hairless forehead skin was enlarged using a tissue expander and earlobes were resurfaced.

Adolescent

The repair of large peripheral nerves using skeletal muscle autografts: a comparison with cable grafts in the sheep femoral nerve.

Recovery of morphological characteristics was compared in the femoral nerves of sheep at varying times up to 10 months after nerve repair. Groups of sheep receiving coaxially aligned freeze-thawed skeletal muscle autografts were compared with those receiving three-strand cable grafts made from autogenous cutaneous nerve. At all times after implantation more nerve fibres could be counted distal to the muscle grafts than distal to cable grafts. Indices of nerve fibre maturation were indistinguishable between the two groups at 10 months. The results are discussed in relation to the possible use of the technique for repairing large mixed nerves.

Animals

Torsion of an accessory spleen in an elderly patient.

Torsion of an accessory spleen is recognized as a rare cause of acute abdominal pain in childhood. A case is reported which, however, is unusual in that it occurred in a patient of 75, who had had no previous symptoms which might have suggested the presence of an accessory spleen.

Abdomen, Acute