Hebe Désirée Kvernmo

Wavelet analysis of oscillations in the peripheral blood circulation measured by laser Doppler technique

The wavelet transform technique, a time-frequency method with logarithmic frequency resolution, was used to analyze oscillations in human peripheral blood flow measured by laser Doppler flowmetry. The oscillations extended over a wide frequency state and their periods varied in time. Within the frequency range studied, 0.0095-1.6 Hz, five characteristic oscillations were revealed, arising from both local and central regulatory mechanisms. After the insertion of endothelium-dependent and endothelium-independent vasodilators the spectra of blood how markedly differed in the frequency interval 0.0095-0.02 Hz. In this way it was demonstrated that endothelial activity is a rhythmic process that contributes to oscillations in blood flow with a characteristic frequency of around 0.01 Hz. The study illustrates the potential of laser Doppler flowmetry combined with dynamical systems analysis for studies of both the micro- and macroscopic mechanisms of blood flow regulation in vivo.

Human skin microcirculation after brachial plexus block evaluated by wavelet transform of the laser Doppler flowmetry signal.

Background:The skin microcirculation may be evaluated noninvasively by laser Doppler flowmetry and iontophoresis with acetylcholine and sodium nitroprusside. Wavelet transform of the perfusion signal shows periodic oscillations of five characteristic frequencies in the interval 0.0095–1.6 Hz. The aim of the current study was to investigate alterations in skin microcirculation induced by brachial plexus block, with emphasis on the periodic oscillations. Methods:Healthy nonsmokers undergoing hand surgery (n = 13) were anesthetized with brachial plexus block, using bupivacaine, lidocaine, and epinephrine. Skin microcirculation was evaluated by laser Doppler flowmetry and iontophoresis with acetylcholine and sodium nitroprusside before and after brachial plexus block. Wavelet transform of the perfusion signal was performed. As a control group, 10 healthy nonsmokers were included. Results:In the anesthetized arm, skin perfusion after brachial plexus block increased from 19 (12–30) to 24 (14–39) arbitrary units (P < 0.01). A significant increase was also seen in the contralateral arm from 17 (14–32) to 20 (14–42) arbitrary units (P < 0.01). After brachial plexus block, spectral analysis revealed a significant reduction in relative amplitude of the oscillatory components within the 0.0095- to 0.021- (P < 0.001) and 0.021- to 0.052-Hz (P < 0.001) intervals in the anesthetized arm. Conclusion:Alterations in skin microcirculation induced by brachial plexus block can be evaluated by wavelet transform of the laser Doppler flowmetry signal. Brachial plexus block reduces the oscillatory components within the 0.0095- to 0.021- and 0.021- to 0.052-Hz intervals of the perfusion signal. These alterations are related to inhibition of sympathetic activity and a possible impairment of endothelial function.

Enhanced endothelium-dependent vasodilatation in human skin vasculature induced by physical conditioning

Functional alterations to the endothelial cells of the vascular system may contribute to the improved circulatory performance induced by physical conditioning. We evaluated microvascular reactivity to iontophoretic application of acetylcholine (ACh) and sodium nitroprusside (SNP) through the skin and blood perfusion measurements in the same area using laser Doppler flowmetry. Whereas ACh acts on smooth muscle cells of the vascular system via the production of vasodilator substances from the endothelium, SNP is an endothelium-independent vasodilator acting on vascular smooth muscle cells directly. The study was performed using two groups of subjects with different levels of aerobic endurance, long distance runners competing at national level (n = 9) and controls (n = 9). The subjects were tested for 40 min on a treadmill before and after an exercise test at 80% of their maximal oxygen uptake. During stimulation by ACh cutaneous perfusion increased to a higher level in the athletes than in the controls (overall P < 0.05), whereas an acute period of exercise abolished this difference (overall P > 0.6). There was no significant difference between the athletes and the controls with respect to the SNP-induced increase in cutaneous perfusion either before (P > 0.9) or after (P > 0.9) exercise. The higher cutaneous perfusion responses to stimulation with ACh in the athletes than in the controls may support the hypothesis that regular exercise modifies the responsiveness of the cutaneous endothelium. The difference in ACh-induced perfusion and in unstimulated forearm perfusion between the two groups was present only at rest. This finding indicated that mechanisms were introduced during exercise, which compensated for the lower endothelial sensitivity to stimulation in the controls at rest.

Volar Locking Plates Versus External Fixation and Adjuvant Pin Fixation in Unstable Distal Radius Fractures: A Randomized, Controlled Study

PURPOSE To determine whether volar locking plates are superior to external fixation with adjuvant pins in the treatment of unstable distal radius fractures. METHODS A total of 111 unstable distal radius fractures were randomized to treatment with external fixation (EF) using adjuvant pins or with a volar locking plate (VLP). The mean age of the patients was 54 years (range, 20-84 y). Seven patients were lost to follow-up. At 1 year, 104 patients were assessed with a visual analog scale pain score, Mayo wrist score, Quick-Disabilities of the Arm, Shoulder, and Hand (QuickDASH), range of motion, and radiological evaluation. The QuickDASH score at 52 weeks was the primary outcome measure. RESULTS The operative time in the EF group was 77 minutes, compared with 88 minutes in the VLP group. At 52 weeks, patients with VLPs had a higher Mayo wrist score (90 vs. 85), better supination (89° vs. 85°), and less radial shortening (+1.4 mm vs. +2.2 mm). There were more patients with pain over the ulnar styloid in the EF group (16 vs 6 patients). For AO type C2/C3, the patients with VLPs had better supination (90° vs. 76°) and less ulnar shortening (+1.1 mm vs. +2.8 mm). The complication rate was 30% in the EF group, compared with 29% in the VLP group. Eight (15%) plates were removed due to complications. The QuickDASH score was not significantly different between the groups. CONCLUSIONS Although we did not find a significant difference between the groups for the QuickDASH score, we believe that our results support the use of VLPs for the treatment of unstable distal radius fractures. A serious concern is that some patients will have to have their plates removed; therefore, improving the surgical technique is important. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic I.

THE EFFECT OF PHYSICAL CONDITIONING SUGGESTS ADAPTATION IN PROCOAGULANT AND FIBRINOLYTIC POTENTIAL

Acute exercise evokes a transient increase in procoagulant activity. We evaluated the effect of physical conditioning on the activation of the coagulation and fibrinolytic systems. Two groups of subjects of different aerobic endurance levels (athletes and controls with maximal oxygen uptake (VO2max) 68.4 and 52.6 ml kg-1 min-1, respectively), were tested at rest and after standardized exercise at 80% of their individual VO2max. There was a significant increase in prothrombinfragment 1 + 2 (F1 + 2) level among controls in response to standardized exercise (p < 0.05), whereas no significant difference in the level of F1 + 2 between athletes and controls at rest or in response to exercise was demonstrated. Tissue plasminogen activator (tPA) antigen level at rest was significantly lower in athletes compared to controls (p < 0.03). A significant increase was found in the tPA level after standardized exercise in both groups (p < 0.02), which was lower in athletes compared to controls (p < 0.05). There were no significant differences between athletes and controls in plasminogen activator inhibitor-1 (PAI-1) and thrombin antithrombin complex (TAT) levels at rest. Athletes had a significantly lower PAI-1 level than controls after exercise (p < 0.05). In conclusion, the present study suggests an increased activation of the coagulation system in response to exercise in controls only. It also suggests adaptive changes in fibrinolytic potential induced by physical conditioning, as demonstrated by the lower level of tPA at rest and the lower levels of tPA and PAI-1 after exercise in athletes compared to controls.

Changes in blood cell response following strenuous physical exercise.

SummaryThe generation of tumour necrosis factor (TNF) and tissue factor activity in lipopolysaccharide (LPS) stimulated blood were studied in 25 healthy subjects before and after physical exercise of different intensities. Of the subjects a group of 9 were athletes who trained once to twice every day of the week, a second group of 8 exercised 3–7 times a week, and a third group of 8 exercised 4–5 times a month. The production of TNF in freshly drawn LPS stimulated blood in heparin, drawn from top athletes at rest was significantly lower than in the other subjects. The LPS induced concentrations of TNF-α of 2.73 (SEM 1.05) ng · ml−1 in the blood of the top athletes compared to 5.08 (SEM 0.7) ng · ml−1 and 7.6 (SEM 1.6) ng · ml−1, respectively, in the other two groups. The group that trained the least had the highest values. Immediately after exercise, the monocytes appeared to be less responsive to LPS stimulation, as a reduction of 47%–48% was observed in the top athletes and in the other group of well-trained individuals. The group that trained the least, which was also subjected to the least stressful exercise, had a 33% reduction in TNF production. Within 6 h the TNF concentration was back to pre-exercise values. Within 6 h the TNF concentration was back to pre-exercise values. In contrast to TNF production, the LPS induced tissue factor activity of monocytes was significantly higher in the top athletes and in the group of well-trained individuals when measured immediately after 10 min of exercise compared to pre-exercise values. The increase in tissue factor activity was probably a reflection of simultaneous granulocyte- and platelet activation which is known to enhance LPS induced tissue factor activity in monocytes. Except for the period immediately after exercise, there was a significant correlation between LPS induced TNF and tissue factor activity in the whole blood of the participants. In conclusion, hard physical training appeared to suppress the availability of TNF in stimulated blood. This was even more pronounced immediately after strenuous physical exercise.

Isolated, extra-articular neck and shaft fractures of the 4th and 5th metacarpals: a comparison of transverse and bouquet (intra-medullary) pinning in 67 patients

Although extra-articular metacarpal fractures are common, there is no consensus on the mode of treatment. We evaluated the outcome in 67 patients operated for isolated, extra-articular fractures in the neck or shaft of the ulnar two metacarpals 28 months post-operatively. There were 22 bouquet (intra-medullary) pinnings and 45 transverse pinnings; 11 were lost to follow-up. Overall, hand function was good, and no difference was detected between the two methods (QuickDASH, grip strength, range of motion, VAS pain and VAS satisfaction). Many patients suffered complications: 12% had a superficial infection (all treated with transverse pinning with wires left exposed); 39% had some impairment in skin sensation; 29% reported cold intolerance; and 10% had other complications. Due to the potential risk of a secondary fracture of the neighbouring metacarpal after transverse pinning, we recommend bouquet (intra-medullary) pinning. We also recommend burying wires beneath the skin surface to avoid infection.

Conservative treatment has comparable outcome with bouquet pinning of little finger metacarpal neck fractures: a multicentre randomized controlled study of 85 patients.

Current literature gives few guidelines regarding indication for operative treatment of little finger metacarpal neck fractures, and some surgeons choose operative treatment when the palmar angulation exceeds 30°. The objective of this study was to determine whether conservative treatment produces comparable outcomes with bouquet pinning in a randomized, controlled trial. Eighty-five patients with little finger metacarpal neck fractures with ≥30° palmar angulation in the lateral view were included. Patients were randomized to two groups: conservative treatment without reduction of the fracture (43 patients); and closed reduction and bouquet pinning (42 patients). After 1 year, there were no statistical differences between the groups in QuickDASH score, pain, satisfaction, finger range of motion, grip strength, or quality of life. There was a trend versus better satisfaction with hand appearance (p = 0.06), but longer sick leave (p < 0.001) and more complications (p = 0.02) in the operative group. Level of evidence: Level 2

Assessment of volar angulation and shortening in 5th metacarpal neck fractures: an inter- and intra-observer validity and reliability study

Four methods for measuring volar angulation in 5th metacarpal neck fractures were tested for validity and reliability. Mid-medullary canal measurement in the lateral view (method MC-90) has previously been proven valid in a cadaveric study, hence used as a reference to test validity of the latter three. These three yielded a significant different mean fracture angle compared with MC-90, with only minor enhancement in reliability. Therefore, none of these three methods is recommended as a better standard method than the MC-90, where reliability was found to be substantial (intraclass correlation coefficient 0.53–0.81). Two methods for measuring shortening in 5th metacarpal neck fractures were compared, and stipulation of shortening by drawing a line through the most distal point of the heads of the neighbouring 3rd and 4th metacarpals (method SH-Stip) is a simple method with excellent reliability (intraclass correlation coefficient 0.81–0.96) for estimating shortening, requiring only radiological examination of the injured hand.

Posttraumatic Reconstruction of the Hand—A Retrospective Review of 87 Toe-to-Hand Transfers Compared With an Earlier Report

PURPOSE The purpose of this study was to retrospectively review the results of 87 toe-to-hand transfers performed in 73 procedures, compare them to the report published by the senior author in 1983, and confirm the hypothesis that results of toe-to-hand transfers at our center have improved over time. METHODS The results of 87 toe-to-hand transfers performed between 1981 and 2001 were reviewed and compared with the results of 54 toe-to-hand transfers performed between 1974 and 1980. The measured parameters were type of reconstruction performed, anticoagulation therapy, vascular patency, frequency of secondary surgery, and strength of thumb reconstructions. RESULTS In the recent time period, 11% of the procedures had complications with revascularization of the transferred digit, and long-term survival was seen in 98% of the toe-to-hand transfers. This is a significant improvement over earlier results, in which 33% of the cases had some microvascular compromise and the survival of grafts was lower (91%). Pinch strength for thumb reconstructions improved, and the number of secondary surgeries performed dropped, but neither of these parameters reached a significant level. Toes used for reconstruction changed, with an 18% decrease in use of big toe for thumb reconstruction and a similar increase in use of the second toe. For non-thumb digital reconstructions there was a 60% decrease in use of second and third toe combined, whereas use of the second toe alone increased similarly. CONCLUSIONS This study showed reduction of the incidence of vascular compromise compared to the previous report. Improved strength of thumb reconstructions and reduced need for secondary surgery was also displayed. These findings are likely attributed to refinements in reconstructive procedures and operative techniques. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.