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Biomedical subjects

G Lundborg

Publications and source records attributed to G Lundborg.

At least 37 records · Page 2Linked to original sources
PubMed2001

The long term recovery curve in adults after median or ulnar nerve repair: a reference interval.

This study presents a predicted five-year reference interval for the outcome following repair of the median or ulnar nerve in adults. Forty-four patients were examined with the use of a recently introduced model instrument for documentation after nerve repair that includes "sensory", "motor", and "pain/discomfort" outcomes which together constitute a summarized "total score". Analysis of the "total score" showed that follow-up time and age significantly influence the outcome. There were obvious inferior "motor" results after ulnar nerve injury, but these did not significantly influence the "total score". Significant improvements in the "total score" were seen throughout the follow-up period.

Adolescent↗
PubMed2001

Nerve regeneration enhancement by tourniquet.

The use of tourniquet compression as a non-invasive method to enhance axonal regeneration was assessed in the rat sciatic nerve. One hind limb of the rat was subjected to compression by a tourniquet set at 300 mmHg for 30 or 120 min followed by bilateral test crush lesions performed either directly or after a conditioning interval of 3 or 6 days, with the non-compressed side serving as a control. Axonal regeneration distances were evaluated after 3 days by the pinch reflex test. We found that compression caused an increased outgrowth length of sensory axons compared to the controls. The effect was most obvious after 120 min of compression with a conditioning interval of 6 days. Tourniquet compression has a conditioning lesion effect on peripheral nerve and may enhance nerve regeneration.

Animals↗
PubMed2001

Use of chemically extracted muscle grafts to repair extended nerve defects in rats.

Nerve regeneration, measured as axonal outgrowth, Schwann cell migration, macrophage invasion, and neovascularisation, was compared after repair of a 15 mm gap in rats' sciatic nerves using autologous muscle grafts made acellular either by freezing and thawing or by chemical extraction. Both extracted and freeze-thawed acellular muscle grafts could be used to bridge the defect. However, axons and Schwann cells, as shown by immunohistochemical staining for neurofilaments and S-100 protein, respectively, grew faster into the extracted muscle grafts than into the freeze-thawed acellular muscle grafts and somewhat more axons were observed in the former graft. There were no significant differences between the two graft types with respect to neovascularisation as showed by staining for endothelial alkaline phosphatase, and limited differences concerning invasion of macrophages (ED1 and ED2) as detected by immunocytochemistry. The results showed that chemically extracted muscle grafts could be used to bridge an extended nerve defect and that such grafts in some aspects were superior to freeze-thawed muscle grafts for extended gaps.

Alkaline Phosphatase↗
PubMed2001

Effects of gradual bone lengthening on the rabbit tibial nerve.

Little is known about the effect of gradual bone lengthening on peripheral nerves. In the present study, an external fixation device was applied to the rabbit tibia, which was then divided. After seven days, the tibia was subjected to 0.7 mm/day callus distraction for periods of up to one month. The tibial nerve was fixed in glutaraldehyde and plastic sections were cut in longitudinal and transverse planes for light and electron microscopy. Light microscopy showed a 64% increase in the gap length at the node of Ranvier in myelinated axons from the experimental side compared with the control side. The cross-sectional area of the non-myelinated axons was not altered significantly. We conclude that gradual stretching of the nerve elongates the nerve fibres at least at the region of the nodes, perhaps a point of least resistance. Diameters of fibres seem to be held more constant during the lengthening procedure.

Animals↗
PubMed2001

Tissue response to silicone tubes used to repair human median and ulnar nerves.

Silicone tubes of appropriate sizes were used to enclose the injured zone of transsected ulnar and median nerves in the human forearm as an alternative to conventional microsurgical repair of the nerve trunk. A gap measuring 3-5 mm was left intentionally between the nerve ends inside the tube. The clinical early results from a prospective randomised study that compared these two principles have recently been presented. Seven patients (five men and two women), aged 15-49 years (median 20) were reexplored 12-44 months (median 22) after the initial procedure because of local discomfort from the tube in four patients. There was a new nerve structure bridging the former gap and in most cases it was impossible to distinguish the site of the injury. In all cases there was a thin capsule around the silicone tube that microscopically consisted of connective tissue with thin walls and no signs of inflammation, granuloma or macrophages (n = 4), while in two cases a mild foreign body reaction was seen at a single site (n = 1) or at patchy areas (n = 1). These results indicate that after more than one year there is a limited tissue reaction around silicone tubes used to repair median and ulnar nerves in humans.

Adolescent↗
PubMed2001

Vibration-induced hand problems: role of the peripheral nerves in the pathophysiology.

A substantial number of people who are exposed to vibrating hand-held tools develop vasospastic and sensorineural symptoms that may seriously affect the ability to work. Apart from the discomfort of the disease itself, this leads to socioeconomic problems for the patients and high costs for the society. The diagnosis of the neurological symptoms is sometimes difficult and may be misinterpreted as a nerve compressive disorder such as carpal tunnel syndrome, which may also develop. This review summarises our available knowledge about the pathophysiology of the neurological dysfunction with reference to hand problems after exposure to vibrating hand-held tools.

Animals↗
PubMed2001

Osseointegrated silicone implants for joint reconstruction after septic arthritis of the metacarpophalangeal joint: a 10-year follow-up.

Seven men mean age 37 years (range 24-45) who had destroyed metacarpophalangeal joints as a result of pyogenic infection underwent reconstruction of the joint with osseointegrated silicone implants. The interval from infection to reconstruction varied from 5 months to 13 years. At mean follow-up 10 (8-12) years postoperatively the titanium fixtures were all well osseointegrated. The silicone spacer had fractured in one case. The extension lag was 16 (10-20) degrees and the range of movement (ROM) 34 (30-40) degrees. Our data confirm previous observations about the successful long-term osseointegration of titanium fixtures used for the attachment of joint prostheses in the hands of patients with rheumatoid arthritis or osteoarthritis. We conclude that titanium fixtures can be used successfully to fix joint mechanisms for reconstruction of small joints after pyogenous arthritis of the hand and can be used for fixation of joint mechanisms in such cases.

Adult↗
PubMed2001

Neural regeneration along longitudinal polyglactin sutures across short and extended defects in the rat sciatic nerve.

OBJECT: The authors have previously shown that longitudinal sutures without artificial tube support regeneration across a 7-mm gap in the rat sciatic nerve. In the present study, the authors compared this new approach with the use of autologous nerve grafts across short defects and examined whether the approach could be used to support regeneration across extended gaps and whether the interposition of a short nerve segment (the stepping-stone procedure) was applicable in this model. METHODS: Longitudinal sutures were used to bridge 7- and 15-mm gaps in the rat sciatic nerve. Contralateral comparisons were made to nerve autografts in the 7-mm group and to sutures plus a short interposed nerve segment in the 15-mm group. Regeneration was evaluated at 2, 4, and 12 weeks by using immunocytochemical analysis for Schwann cells, neurofilament protein, and macrophages and at 12 weeks also by using histological examination, including morphometry in the distal tibial trunk and tetanic force measurements in the gastrocnemius muscle. CONCLUSIONS: The authors found that the results of regeneration after repair with longitudinal polyglactin sutures across short defects were not significantly different from those produced by the use of autologous nerve grafts. Regeneration, although poor, occurred along sutures across extended gaps and was significantly enhanced by an interposed nerve segment acting as a Schwann cell resource in this model.

Animals↗
PubMed2001

Use of tubes in peripheral nerve repair.

The use of tubes as an alternative to primary nerve suture in fresh nerve transections has been introduced as a biologic approach to nerve injuries, creating optimal conditions for axonal regeneration over a short empty space intentionally created between the proximal and distal nerve ends. The idea may seem controversial and has been criticized using the arguments that silicone in itself may create problems like inflammation and the tube may compress the nerve ends. With the use of appropriately sized tubes for bridging a maximum 5-mm gap in human median and ulnar nerves, the authors have found the technique to be useful and persistent at follow-up examinations for up to 4 to 5 years. In addition, from the intellectual point of view, the principle illustrates the concept by which emphasis is placed on the intrinsic healing capacities of the nerve rather than on the technical skill of the surgeon. The thin mesothelial lining found around the silicone tube lacks primary inflammatory signs at follow-up after 1 year, and no signs of compression are seen. It may be an advantage because it allows sliding of the repair site against the surrounding tissues. Tubes made of bioresorbable material may seem ideal, but they may introduce new problems associated with the resorption process in terms of a substantial unrestricted macrophage invasion, fibrosis, and disorganized axonal growth. For an extended nerve defect, the use of autologous nerve grafts is still the gold standard, because no tubular conduit or other conduit has so far proved equal to autologous nerve grafts, at least not for reconstruction of human median and ulnar nerve trunks. Alternatives other than tubes are currently being developed and investigated. For the future, the use of tubes for repair and reconstruction of nerves may have interesting potentials, because such a structure allows several types of tissue engineering. Various matrices containing, for instance, appropriate cells, factors, or other stimulating agents can be introduced in the tube lumen and can also be incorporated in a slow-release form in the walls of the tube and manipulated. Cultured Schwann cells or other cellular components, with or without manipulated production machinery, are probably the cells of choice for introduction in the tubes. Tubes may thus prove to be interesting alternatives to conventional repair techniques for primary repair of nerves and for reconstruction of segmental defects and for neuroma treatment in the future.

Animals↗
PubMed2001

Sensory substitution in prosthetics.

Use of arm and hand prostheses may be essential for many amputees to facilitate activities of daily life and interaction with society. A major drawback that reduces the use of prostheses, however, is the lack of sensibility. Current strategies for sensory feedback in commercially available prostheses are based on force and slip sensors in the mechanical hand for independent grasp control in an opening and closing function. Developing principles for providing conscious sensibility is discussed, including new techniques where hearing is used as substitution for sensation based on sense substitution.

Amputation Stumps↗
PubMed2000

Collateral sprouting from sensory and motor axons into an end to side attached nerve segment.

A nerve segment, sutured end-to-side (ETS) to an intact rat sciatic nerve, becomes invaded by regenerating axons. The origin of these fibres is controversial: it is debated whether or not they represent collateral sprouts from intact axons. Here we demonstrate by double retrograde tracing, using one tracer for the ETS attached segment and another for the sciatic nerve proper double-labelled sensory neurons in 67% of the rats receiving an ETS segments. Double-labelled motor neurons were observed in 11% of the rats. The results show that a nerve segment attached ETS to an intact nerve can induce collateral sprouting of both sensory and motor axons although the extent of such branching may vary with the experimental conditions.

Animals↗
PubMed2000

[Malpractice in connection with radius fractures must be reduced. Clear guidelines for treatment and follow-up are required].

PSR handles the vast majority of malpractice injuries in Sweden. PSR is a claims handling company which settles claims for malpractice on behalf of the insurance company owned by the Swedish county councils: the County Councils Mutual Insurance Company. A central issue in the law regulating patient injuries in Swedish health care is to define injuries that could have been avoided if a certain therapeutic/diagnostic procedure or a more appropriate method had been utilized. PSR arranged a multiprofessional conference regarding guidelines to decrease the number of malpractice injuries in the treatment of distal radius fractures. Among the most important issues defined were: To improve and standardize diagnostic imaging Patient information Early decision making in surgery and physical/occupational therapy A more well-defined indication for surgery, in which type of trauma, biological age and functional demands are considered in addition to radiographs Less stereotyped thinking in follow-up Controlled randomized trials.

Clinical Competence↗
PubMed2000

[Hand transplantation and implantation of nerve chips. New developments within hand surgery].

Injuries and diseases of the hand naturally have an enormous impact on hand function and on quality of life, both occupational and social. The majority of hand-injury patients are under 30 years of age. Hand surgery, an established specialty in Sweden since 1969, is of great importance in terms of clinical developments, education and research. In the coming decade, scientific and clinical advances are to be expected in several fields such as nerve injuries including brachial plexus lesion, microsurgery, flexor tendon injuries and tendon transfer. Bioimplant research and new advances at the biotechnological interface will yield new options in nerve reconstruction, microchip implants in the nervous system, and the restoration of muscle-tendon function following injury. Artificial limbs with advanced motor and sensory functions will be important future aids in the rehabilitation of amputees. Transplantation of human hands is another promising reconstructive procedure which may open iup new perspectives in the coming millennium.

Amputation, Surgical↗
PubMed2000

Pedestrians on slippery surfaces during winter--methods to describe the problems and practical tests of anti-skid devices.

Every year there are thousands of pedestrians in Sweden who are injured because of slippery pavements and roadways. Using an appropriate anti-skid device may reduce the risk of slips and falls on ice and snow. Methods to describe functional problems in walking on different slippery surfaces during winter have been developed as rating scales for evaluating walking safety and walking balance and an observation method to observe posture and movements during walking. Practical tests of all 25 anti-skid devices on the market in Sweden were carried out on different slippery surfaces; gravel, sand, salt, snow and ice. The anti-skid devices were described according to the subjects' perception of walking safety, walking balance and priority for own use. The postures and movements during walking were analysed by an expert physical therapist. The wholefoot device 'studs' was perceived as the best according to walking safety and walking balance and had the highest priority for own use.

Accidental Falls↗
PubMed2000

A 25-year perspective of peripheral nerve surgery: evolving neuroscientific concepts and clinical significance.

In spite of an enormous amount of new experimental laboratory data based on evolving neuroscientific concepts during the last 25 years peripheral nerve injuries still belong to the most challenging and difficult surgical reconstructive problems. Our understanding of biological mechanisms regulating posttraumatic nerve regeneration has increased substantially with respect to the role of neurotrophic and neurite-outgrowth promoting substances, but new molecular biological knowledge has so far gained very limited clinical applications. Techniques for clinical approximation of severed nerve ends have reached an optimal technical refinement and new concepts are needed to further increase the results from nerve repair. For bridging gaps in nerve continuity little has changed during the last 25 years. However, evolving principles for immunosuppression may open new perspectives regarding the use of nerve allografts, and various types of tissue engineering combined by bioartificial conduits may also be important. Posttraumatic functional reorganizations occurring in brain cortex are key phenomena explaining much of the inferior functional outcome following nerve repair, and increased knowledge regarding factors involved in brain plasticity may help to further improve the results. Implantation of microchips in the nervous system may provide a new interface between biology and technology and developing gene technology may introduce new possibilities in the manipulation of nerve degeneration and regeneration.

Anastomosis, Surgical↗
PubMed2000

A model instrument for the documentation of outcome after nerve repair.

We present a new model for documentation and quantification of the functional outcome after nerve repair at the wrist or distal forearm level and a protocol that includes a numerical scoring system. The model, presented here along with validation and reliability test results, supports our hypothesis that the summarized test results reflecting specific functional limitations correlates well with the patient's opinion of the impact of the nerve injury on activities of daily living. Seventy patients with nerve repair were examined using the protocol. Analysis included 3 factors: sensory domain (sensory innervation, tactile agnosis, and finger dexterity), motor domain (motor innervation and grip strength), and pain/discomfort domain (hyperaesthesia and cold intolerance). The analysis explained 73% of the variances of the variables and the variables had a logical distribution between the factors. Analysis of internal consistency demonstrated good homogeneity. A calculated total score correlated strongly with the patients' global estimation of the impact of the injury on activities of daily living and the summary of sensory and pain/discomfort domains correlated significantly with the Medical Research Council S0-S4 scale. The presented model represents a useful new tool for evaluation of the functional outcome after nerve injury and repair.

Adolescent↗
PubMed2000

Brain plasticity and hand surgery: an overview.

The hand is an extension of the brain, and the hand is projected and represented in large areas of the motor and sensory cortex. The brain is a complicated neural network which continuously remodels itself as a result of changes in sensory input. Such synaptic reorganizational changes may be activity-dependent, based on alterations in hand activity and tactile experience, or a result of deafferentiation such as nerve injury or amputation. Inferior recovery of functional sensibility following nerve repair, as well as phantom experiences in virtual, amputated limbs are phenomena reflecting profound cortical reorganizational changes. Surgical procedures on the hand are always accompanied by synaptic reorganizational changes in the brain cortex, and the outcome from many hand surgical procedures is to a large extent dependent on brain plasticity.

Brain↗