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Biomedical subjects

Göran Lundborg

Publications and source records attributed to Göran Lundborg.

26 records · Page 2Linked to original sources
PubMed2003

Behavioural treatment of post-traumatic and vibration-induced digital cold sensitivity.

Cold sensitivity is a common problem after all types of hand injuries. The aim of the present study was to assess possible effects of treatment by Pavlovian conditioning, a behavioural treatment method for digital cold sensitivity where whole body cold exposure becomes associated with warm hands. Eighteen hand-injured patients and nine patients with vibration-induced problems in their hands completed the treatment. Questionnaires and questions, assessment of perception of touch/pressure and skin temperatures after cold provocation, was made before and after the completed period of treatment and after 6 and 12 months. The results indicated subjective improvement in the hand-injured group in contrast to a lack of response in the vibration group. An increased digital skin temperature after treatment was noted for the vibration-exposed group only, which however did not persist at 6 and 12 months' follow-up.

Adult↗
PubMed2003

A comparison of peripheral nerve regeneration in acellular muscle and nerve autografts.

Regeneration of the rat sciatic nerve through acellular muscle and nerve autografts was evaluated 6-28 days postoperatively by the sensory pinch test, immunocytochemical staining for neurofilaments, and light and electron microscopy. Data points generated by the pinch test were plotted against postoperative time periods and by the use of regression analysis the initial delay period for muscle grafts was determined to 10.3 days. This value was similar to that previously published for acellular nerve grafts (9.5 days), but significantly longer than that for fresh nerve grafts (3.6 days). The calculated regeneration rate (slope of the regression line) for muscle grafts (1.8 mm/day) did not differ significantly (p > 0.05) from that calculated for acellular nerve grafts (2.1 mm/day) or for fresh nerve grafts (1.5 mm/day). The front of regenerating axons shown by axonal neurofilament staining confirmed the pinch test results. Both types of acellular grafts were repopulated with host non-neuronal cells and the muscle graft contained occasional ectopic muscle fibres. Remnants of graft basal laminae were evident at the ultrastructural level. These results indicate the suitability of either acellular muscle or nerve grafts for nerve repair despite their prolonged initial delay periods compared with conventional fresh nerve grafts.

Animals↗
PubMed2003

Early use of artificial sensibility to improve sensory recovery after repair of the median and ulnar nerve.

Artificial sensibility based on use of a "tactile glove" which substitutes for lack of sensory afferent inflow with acoustic feedback, was used early after repair of the median and ulnar nerves in a 21-year-old man. After six and 12 months the functional outcome exceeded what is expected in adults, and analysis with calculations for the minimal detectable change (MDC) in tactile gnosis showed a true change. This case highlights the timing of sensory re-education after nerve repair and also emphasises the importance of early restitution of afferent inflow from a denervated hand during rehabilitation.

Adult↗
PubMed2003

Richard P. Bunge memorial lecture. Nerve injury and repair--a challenge to the plastic brain.

Repair and reconstruction of major nerve trunks in the upper extremity is a very challenging surgical problem. Today, there is no surgical repair technique that can assure recovery of tactile discrimination in the hand of an adult patient following nerve repair. In contrast, young individuals usually attain a complete recovery of functional sensibility. The outcome from nerve repair depends mainly on central nervous system factors including functional cortical reorganizational processes caused by misdirection in axonal outgrowth. Deafferentation due to local anesthetic block, amputation or nerve transection in the upper extremity leads to very rapid cortical synaptic remodeling, resulting in a distorted cortical hand representation as well as in enlarged and overlapping cortical receptive fields. Sensory relearning programs are aimed at refinement of these receptive fields to normalize the distorted hand map and improve processing at a high-order cortical level in the context of the 'new language spoken by the hand'. As peripheral nerve repair techniques cannot be further refined, there is a need for new and improved strategies for sensory relearning following nerve repair. We propose the utilization of multimodal capacity of the brain, using another sense (hearing) to substitute for lost hand sensation and to provide an alternate sensory input from the hand early after transection. The purpose was to modulate cortical reorganizations due to deafferentation to preserve cortical hand representation. Preliminary results from a prospective clinical randomized study indicate that the use of a Sensor Glove System, which stereophonically transposes the friction sound elicited by active touch, results in improved recovery of tactile discrimination in the nerve-injured hand. Future strategies for treatment of nerve injuries should promote cellular methods to minimize post-traumatic nerve cell death and to improve axonal outgrowth rate and orientation, but high on the agenda are new strategies for refined sensory relearning following nerve repair.

Adolescent↗
PubMed2002

Functional recovery in a tendon autograft used to bridge a peripheral nerve defect.

The functional recovery was examined after two different methods had been used to bridge an extended nerve gap. A 15 mm defect in the rat sciatic nerve was repaired using a tendon autograft--a new graft material--on one side and a freeze-thawed muscle graft--a well established experimental material--on the other side. Evaluation after 12 weeks included measurements of tetanic force in the gastrocnemius muscle and computerised morphometry of the tibial nerve. The muscular tetanic force recovered to 26% and 21% of control muscles, respectively, but there were no significant differences between the two types of grafts in any of the measurements. The number of regenerated axons of the tibial nerve correlated with functional recovery as judged by muscular tetanic force in the gastrocnemius muscle. We conclude that the tendon autograft supports functional recovery, as judged by return of muscular tetanic force, to an extent comparable to that of the freeze-thawed muscle graft.

Animals↗
PubMed2002

Granular cell tumour of the ulnar nerve in a young adult.

Granular cell tumours in peripheral nerve trunks are extremely rare. We report a case of a granular cell tumour of the ulnar nerve just distal to the elbow in a 16-year-old man. The appearance of the intraneural tumour could not be differentiated by magnetic resonance imaging (MRI) from more common nerve tumours. At exploration it was impossible to excise the tumour radically. Microscopic examination showed a clearly benign tumour and no malignant transformation has been found at follow-up after three and a half years.

Adolescent↗
PubMed2000

Axonal outgrowth in muscle grafts made acellular by chemical extraction.

Purpose: To compare nerve regeneration in autologous detergent extracted and freeze-thawed muscle grafts and to electrophoretically characterize the grafts. Methods: Autologous acellular muscie grafts were created either by freeze/thawing or by detergent extraction and then used to bridge a 10 mm gap in rat sciatic nerve. The autologous grafts were compared with respect to protein content, using electrophoresis preimplantation, and axonal outgrowth, Schwann cell and macrophage content, using immunocytochemistry (neurofilaments, S-100 protein, ED 1 macrophages) at 5-20 days postimplantation. Results: The extracted muscle grafts were elastic, but the amount of several proteins was reduced and laminin was still present at a position of basal laminae of the muscle fibers. The freeze/thawed grafts were brittle and lacked elasticity, but resulted in minor changes in major proteins. The axons regenerated through both types of grafts (initial delay 6 days and rate 0.7-0.8 mm/day), which shrunk in length by 25%. There were no apparent differences with respect to Schwann cells and macrophages. Conclusions: The results suggest that detergent extracted muscle tissue, in which some basal lamina proteins remain but cells are removed, could present a new favourable option for nerve grafting.

Journal Article↗