[Easy to misunderstand patients with "white fingers". Vibrating tools may cause sensory disorders].
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Diagnosis, Differential↗
Biomedical subjects
G Lundborg
Publications and source records attributed to G Lundborg.
Hand problems in 100 vibration-exposed symptomatic male workers.
Long-term use of hand-held vibrating tools may induce various types of hand problems. One hundred symptomatic men exposed to vibration from such tools were interviewed and examined with special reference to neurosensory and vasospastic problems. Three distinct symptomatic groups were identified: isolated neurosensory symptoms (48%), isolated vasospastic problems (20%), and combined neurosensory and vasospastic problems (32%). Abnormal cold intolerance (pain and coldness without blanching of the fingers on exposure to cold) occurred in 27% of the patients. Neurosensory problems were more predominant than vasospastic ones, especially during the first 20 years of vibration exposure. Of 80 patients with neurosensory symptoms, only 22 had signs of a carpal tunnel syndrome (CTS). It is concluded that vibration-induced neurosensory and vasospastic symptoms can occur separately or together, and that the neurosensory symptoms are often not due to a CTS.
Adult↗
Impaired regeneration in rat sciatic nerves exposed to short-term vibration.
We have studied the effects of vibration on the regeneration capacity of the peripheral nerve. A rat model was used where one hind limb was subjected to vibration of defined magnitude and duration while the contralateral hind limb was not exposed to vibration. Seven days later, the sciatic nerves were transected bilaterally and cross-joined giving the following groups: group A, a proximal vibrated nerve end sutured to a non-vibrated distal nerve end; group B, a non-vibrated proximal nerve end sutured to a distal vibrated nerve end, and group C, non-vibrated proximal nerve end sutured to a non-vibrated distal nerve end. The regeneration distances were measured 3, 6 and 8 days after surgery. The control group showed a normal linear outgrowth. The outgrowth in the two experimental groups was initially not different to controls but later became significantly different, indicating a retardation of outgrowth in these groups. It is concluded that short-term exposure to vibration can impair nerve regeneration after transection and nerve repair.
Animals↗
Is vibration-induced white finger a reversible syndrome if vibration is stopped?
The purpose of the study was to investigate if vibration-induced white finger may be a reversible symptom after cessation of vibration exposure. Fifty-nine welders, previously employed by a ship building company and who had shown various levels of vibration-induced vasospastic symptoms in the hand were interviewed 5 to 6 years after closure of the company. Out of the 43 patients exposed to no or insignificant vibration subsequently, 28 claimed improvement, 11 claimed unchanged problems and four complained of worse problems. Twelve of these patients had the cold provocation test repeated at follow up. One patient showed the same result as 5 years earlier, six showed improvement and five showed much improvement. Of 16 patients with continued vibration exposure none showed subjective improvement, nine claimed unchanged problems while seven patients were worse. It is concluded that vibration-induced white finger is not a progressive condition following cessation of exposure to vibration. On the contrary it may be static or even reversible to some extent.
Adult↗
Tissue displacement is a causative factor in vibration-induced muscle injury.
The early skeletal muscle response to vibration stimulus at two different displacement levels was examined. Twelve rats were anaesthetized and the hind limb was exposed to vibration, 80 Hz, 63 micronsrms (root mean square) (group 1) and 40 Hz; 130 micronsrms (group 2) for 5 hours/day for 2 days. Cross-sectional areas of vibrated muscle fibres were significantly larger in group 2. Sizes of different fibre types were differently affected: the slow-twitch type 1 fibres were significantly enlarged in both groups, while the fast-twitch type 2 fibres demonstrated a mixed response pattern. Centrally positioned muscle fibre nuclei increased significantly after vibration in group 2. It is concluded that the level of tissue displacement is a crucial factor for development of vibration-induced muscle injury.
Animals↗
Effects of hyaluronan on cell proliferation and collagen synthesis: a study of rabbit flexor tendons in vitro.
Hyaluronan (HA), a high-molecular-weight polysaccharide, has been suggested to play a possible role during the early stages of healing of a variety of connective tissues and when topically applied to decrease the formation of adhesions following tendon surgery. As the mechanisms of HA actions are still being discussed, this study was designed to assess the effects of HA on cell proliferation and synthesis of matrix components of deep flexor tendons in a well-defined culture system. Cell proliferation, measured as the radioactive 3H-thymidine uptake by cultured segments of rabbit flexor tendons, was inhibited by the addition of HA to the culture medium. HA of molecular weight 0.5 x 10(6) inhibited the uptake significantly at concentrations within the range of 0.1-2.0 mg/mL, HA of molecular weight 1.6 x 10(6) at 0.5-2.0 mg/mL, and HA of molecular weight 3.6 x 10(6) at 1.0-2.0 mg/mL, as compared to matched control groups. At the concentration of 2 mg/mL, HA of the molecular weights of 0.5, 0.8, 1.6, and 3.6 x 10(6) equally inhibited cell proliferation. No effect on synthesis of matrix components, measured as the radioactive incorporation of 35S-sulfate, 3H-hydroxyproline, and 3H-proline by cultured segments of rabbit flexor tendons, was observed. These findings show that exogenously applied HA may act as a modulator of flexor tendon fibroblast proliferation, indicating a possible mechanism for antiadhesive effects following administration after flexor tendon surgery.
Animals↗
Osseointegrated thumb prostheses: a concept for fixation of digit prosthetic devices.
Three patients with traumatic amputation of the thumb at the metacarpophalangeal joint level underwent a two-stage reconstruction aimed at fixation of a thumb prosthesis to the first metacarpal bone via an osseointegrated titanium fixture. The first stage included insertion of the fixture into the medullary cavity of the first metacarpal bone in combination with transplantation of cancellous bone from the iliac crest. After 3 months, when the fixture was firmly osseointegrated into the bone, a skin-penetrating abutment was placed on top of the fixture, the surrounding skin being thinned to the thickness of a split-skin graft to minimize relative mobility. A thumb prosthesis could then be firmly attached to this fixture. At follow-up examinations between 18 months and 3 years; postoperatively perfect osseointegration of the implant persisted. There were no skin problems. Some extent of tactile discrimination was achieved in the prosthesis hypothetically based on transfer of tactile stimuli to endosteal nerves in the bone via the titanium fixture.
Adolescent↗
Skeletal muscle changes after short term vibration.
Six female Wistar rats were anaesthetised and attached to a vibrating table, (80 Hz/32 m/s2) five hours daily for two days. Histological, enzyme and immunohistochemical, and morphometric analyses of the directly exposed and opposite control plantar muscles were made. Neither fibre necrosis nor regenerative activity were seen. The mean (SD) area (micron2) of vibration-exposed muscle fibres was significantly increased compared with controls (682 (274) and 642 (230), p < 0.05). Both type 1 and 2C fibres were significantly larger after vibration (773 (293) and 650 (223) compared with 683 (209) and 579 (149), p < 0.05) while type 2A and 2AB fibres were not significantly enlarged. The percentage of centrally located nuclei was significantly increased after vibration. This study shows that short term vibration can induce changes in size in muscle fibres. We postulate that this is the first indication of a vibration-induced muscle injury that may develop into chronic impairment of muscle function if the exposure continues for an extended period of time.
Animals↗
Bioartificial nerve grafts. A prototype.
A prototype for a bioartificial nerve graft has been developed. To set a baseline for a series of experimental studies we present a basic model in which multiple polyamide (nylon) filaments inside silicone tubes constitute an intrinsic and extrinsic framework, respectively, for regenerating axons. The prototype was used to bridge a 10 mm gap in rat sciatic nerve (n = 8). Four weeks postoperatively multiple axons organised into minifascicles were observed in all cases between the synthetic filaments and in the space between the filaments and the silicone tube. Pinching of the nerve distal to the prototype caused a response in 50% of the cases indicating the presence of regenerating sensory fibres compared with no response when no conduit had been used to bridge the gap. When an empty tube was used, pinching of the distal segment caused a response in all cases. The finding that regeneration is supported by the filament filled tubes forms a basis for further development of the bioartificial nerve graft concept with special reference to its potential for bridging extended gaps in nerve continuity.
Animals↗
Regeneration across a partial defect in rat sciatic nerve encased in a silicone chamber.
Forty-four rat sciatic nerves with partial defects were repaired with a silicone chamber. Each partial defect was created by resecting a 10 mm segment from the tibial fascicle leaving the peroneal fascicle intact. The proximal and the distal stumps of the tibial fascicle together with the intact peroneal fascicle were encased in a single silicone chamber. After seven days a fibrin matrix had surrounded the peroneal fascicle and spanned the defect between the tibial stumps. This matrix was later invaded by non-neuronal cells and regenerating axons. Non-myelinated nerve fibres had almost regenerated across the defect by 16 days. The tetanic force of the gastrocnemius muscle 120 days after repair showed 80% recovery, which was no different from that of partial defects repaired with conventional nerve grafts. The results suggest that the silicone chamber technique could be applicable to the treatment of partially transected nerve trunks.
Animals↗
Osteotomy of the first metacarpal for osteoarthrosis of the basal joints of the thumb.
A radial, 30 degrees wedge osteotomy was used for treatment of osteoarthrosis of the trapeziometacarpal joint in 18 patients, 16 women and two men, mean age of 61 years (range 38-74). Six of them had involvement of the scaphotrapezial joint. After a mean follow-up of 8.5 months (range 2-21) one of the patients were completely satisfied with the result of the operation, seven were quite satisfied, and two considered themselves unchanged. None was made worse. Of the 12 patients who did not have involvement of the scaphotrapezial joint nine were completely satisfied and three quite satisfied. Grip strength on the operated side was 75.5% (32%-100%), and pulp pinch was 74.5% (30%-100%) of that in the contralateral one. The mobility of the thumb was influenced little by the operation. Wedge osteotomy of the first metacarpal is a simple and safe way of relieving pain, particularly in the early stages of osteoarthrosis of the basal thumb joint.
Adult↗
Anatomy, function, and pathophysiology of peripheral nerves and nerve compression.
The basic pathophysiology of nerve compression injuries is complex and it is important to consider the microanatomy of the neuron and the peripheral nerve. The clinical stages of nerve compression lesions can be related to changes in intraneural microcirculation and nerve fiber structure; alterations in vascular permeability, with subsequent formation of edema; and deterioration of nerve function observed in experimental studies. The double-crush and reversed double-crush syndromes are related to disturbances in axonal transport induced by compression, followed by morphologic and functional changes in the nerve cell bodies. An underlying neuropathy in subjects can make the peripheral nerves more susceptible to compression injuries.
Animals↗
Predegeneration enhances regeneration into acellular nerve grafts.
In the present study, we determined the regeneration rate and the initial delay in rat sciatic nerve grafts first made hypercellular by predegeneration then acellular by freeze-thawing. 7-day predegenerated nerve pieces from the distal nerve stump on the right side were made acellular by repeated freeze-thawing and inserted as grafts into a 10-mm long freshly created defect on the left contralateral side. Freshly made (no predegeneration period) acellular nerve grafts were used as controls. Both types of grafts supported outgrowth of regenerating axons as demonstrated by the sensory pinch test. However, the predegenerated acellular nerve grafts had a significantly shorter initial delay period (2.7 days) as compared with freshly made acellular nerve grafts (9.5 days). The initial delay period for predegenerated acellular nerve grafts was similar to that for fresh cellular nerve grafts but significantly longer than that for predegenerated cellular nerve grafts [24]. The rate of regeneration appeared independent of the type of grafts used. We suggest that modifications of the basal lamina and/or factors produced during the predegeneration period by non-neuronal cells survive the freeze-thawing cycle and account for the decrease in the initial delay period.
Animals↗
Neuropathy in female dental personnel exposed to high frequency vibrations.
OBJECTIVE: To evaluate early neuropathy in dental personnel exposed to high frequency vibrations. METHODS: 30 dentists and 30 dental hygienists who used low and high speed hand pieces and ultrasonic scalers were studied, and 30 dental assistants and 30 medical nurses not exposed to vibration (all women). Vibrotactile sensibility, strength, motor performance, sensorineural symptoms and signs, and vascular symptoms in the hands, as well as mercury concentrations in biological samples and cervicobrachial symptoms, were studied. RESULTS: The two groups exposed to vibration had significant impairments of vibrotactile sensibility, strength, and motor performance, as well as more frequent sensorineural symptoms. In the dentists there were significant associations between the vibrotactile sensibility and strength, motor performance, superficial sensibility, and sensorineural symptoms. There were no associations between these findings and cervicobrachial symptoms, mercury concentrations, or smoking. There was no increase of vascular symptoms of the hands in the groups exposed to vibration. CONCLUSION: Dental hygienists and dentists had a slight neuropathy, which may be associated with their exposure to high frequency vibrations, and which may be detrimental to their work performance. Thus, development of safer equipment is urgent.
Adult↗
Pre-degenerated nerve grafts enhance regeneration by shortening the initial delay period.
In the present study we tested how nerve grafts with different pre-degeneration periods (1-28 days) influenced the early regenerative response in the rat sciatic nerve. The sciatic nerve on the right side was crushed and after 1-28 days of pre-degeneration, a 10 mm segment was used as an autologous nerve graft and transposed to a freshly made 10 mm long nerve defect on the left side. The regeneration distance was measured by the sensory pinch test 2-10 days after nerve repair. A newly developed mathematical model was used to calculate regeneration rates and initial delay periods from the measured regeneration distances. Pre-degenerated nerve grafts improved nerve regeneration by decreasing the initial delay period as compared to fresh nerve grafts without affecting the regeneration rate. Only one day of pre-degeneration was sufficient to reduce the initial delay period from 3.6 days to 1.7 days. The maximal effect on the initial delay period was achieved after 3 days of pre-degeneration. The initial delay period at later pre-degeneration intervals (7-14 days) was about 1 day. The effect persisted for at least 28 days of pre-degeneration. The regeneration rate was 1.5 mm/day for fresh nerve grafts and between 1.8-2.1 mm/day for pre-degenerated grafts. The results suggest that the effects of pre-degeneration are not only due to the increased cell proliferation in the graft, but that also trophic and/or inflammatory mechanisms may be of importance. Grafts pre-degenerated by crush may have clinical implications since they are easy to perform if an elective nerve grafting procedure is planned.
Animals↗
[The man behind the "seeing hand": Erik Moberg. He proved the special sensitivity of the hand].
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General Surgery↗
Pain, nerve dysfunction and fatigue in a vibration-exposed population.
The long term use of hand-held vibrating tools may cause vasospastic and neuromuscular problems. Symptoms include painful blanching of the fingers at low temperatures, intermittent paresthesia and numbness, impaired dexterity, a tendency to drop tools, and an increasing inability to identify small objects by touch alone. Neurological as well as vasospastic problems are graded according to the Stockholm workshop scales. Accurate and early diagnosis is particularly important (e.g., in vibration-exposed patients presenting a carpal tunnel syndrome, it is necessary to distinguish whether compression of the median nerve occurs at the digital, skin receptor or carpal tunnel levels). A variety of improved diagnostic techniques are discussed.
Humans↗
Tubular repair of the median nerve in the human forearm. Preliminary findings.
Transected median nerves in the forearm of two male patients, 12 and 21 years of age, were treated with a chamber technique leaving a 3 to 5 mm gap between the nerve ends. The nerve ends were enclosed in a silicone tube of such a dimension that would not cause compression of the nerve. Post-operative examination including sensory evaluation and assessment of muscle contraction force was carried out after 3 years. In both cases there was excellent motor recovery of the thenar muscles. Outgrowth of sensory fibres was remarkably fast, resulting ultimately in functional sensibility allowing almost normal hand function. 2PD was < or = 6 mm (12-year-old patient) and 8 to 10 mm (21-year-old patient) respectively. In one case the silicone tube was re-explored because of minor local discomfort 2 years after the repair. The former gap was bridged by a smooth continuous nerve-like structure of the same diameter as the adjacent nerve trunk and with no signs of neuroma formation or compression of the nerve.
Adult↗