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- Klaastad, Ö, et al.
(författare)
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Distribution of local anesthetic in axillary brachial plexus block : A clinical and magnetic resonance imaging study
- 2002
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Ingår i: Anesthesiology. - : Ovid Technologies (Wolters Kluwer Health). - 0003-3022 .- 1528-1175. ; 96:6, s. 1315-1324
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is an unsettled discussion about whether the distribution of local anesthetic is free or inhibited when performing brachial plexus blocks. This is the first study to use magnetic resonance imaging (MRI) to help answer this question. Methods: Thirteen patients received axillary block by a catheter-nerve stimulator technique. After locating the median nerve, a total dose of 50 ml local anesthetic was injected via the catheter in four divided doses of 1, 4, 15, and 30 ml. Results of sensory and motor testing were compared with the spread of local anesthetic as seen by MRI scans taken after each dose. The distribution of local anesthetic was described with reference to a 20-mm diameter circle around the artery. Results: Thirty minutes after the last dose, only two patients demonstrated analgesia or anesthesia in the areas of the radial, median, and ulnar nerve. At that time, eight of the patients had incomplete spread of local anesthetic around the artery, as seen by MRI. Their blocks were significantly poorer than those of the five patients with complete filling of the circle, although incomplete blocks were also present in the latter group. Conclusion: This study demonstrated that MRI is useful in examining local anesthetic distribution in axillary blocks because it can show the correlation between MRI distribution pattern and clinical effect. The cross-sectional spread of fluid around the brachial-axillary artery was often incomplete-inhibited, and the clinical effect often inadequate.
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- Klaastad, O, et al.
(författare)
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An evaluation of the supraclavicular plumb-bob technique for brachial plexus block by magnetic resonance imaging
- 2003
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Ingår i: Anesthesia and Analgesia. - 0003-2999 .- 1526-7598. ; 96:3, s. 862-867
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Tidskriftsartikel (refereegranskat)abstract
- Partly based on magnetic resonance imaging studies, the "plumb-bob" approach for brachial plexus block was designed to minimize the risk of pneumothorax. Nevertheless, the risk of pneumothorax has remained a concern. We analyzed magnetic resonance images from 10 volunteers to determine whether the risk of pneumothorax was decreased with this method. The recommended initial needle direction is anteroposterior through the junction between the lateral-most part of the sternocleidomastoid muscle and the superior edge of the clavicle. If the initial placement is not successful, the brachial plexus may be sought in sectors 20░-30░ cephalad or caudad to the anteroposterior line in a sagittal plane through the insertion point. We found that the anteroposterior line reached the pleura in 6 of 10 volunteers without prior contact with the subclavian artery or the brachial plexus, but always with contact with the subclavian vein. To reach the middle of the brachial plexus, a mean cephalad redirection of the simulated needle by 21░ was required (range from 41░ cephalad to 15░ caudad in one case). We conclude that the risk of contacting the pleura and the subclavian vessels may be reduced by initially directing the needle 45░ cephalad instead of anteroposterior. If the brachial plexus is not contacted, the angle should be gradually reduced.
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- Smedby, Örjan, 1956-, et al.
(författare)
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Functional imaging of the thoracic outlet syndrome in an open MR scanner
- 2000
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Ingår i: European Radiology. - 0938-7994 .- 1432-1084. ; 10:4, s. 597-600
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Tidskriftsartikel (refereegranskat)abstract
- Symptoms due to thoracic outlet syndrome may present only in abduction, a position that cannot be investigated in conventional MR scanners. Therefore, this study was initiated to test MRI in an open magnet as a method for diagnosis of thoracic outlet syndrome. Ten volunteers and 7 patients with a clinical suspicion of thoracic outlet syndrome were investigated at 0.5 T in an open MR scanner. Sagittal 3D SPGR acquisitions were made in 0 and 90 degrees abduction. In the patients, a similar data set was also obtained in maximal abduction. To assess compression, the minimum distance between the first rib and the clavicle, measured in a sagittal plane, was determined. In the neutral position, no significant difference was found between patients and controls. In 90 degrees abduction, the patients had significantly smaller distance between rib and clavicle than the controls (14 vs 29 mm; p < 0.01). On coronal reformatted images, the compression of the brachial plexus could often be visualised in abduction. Functional MR examination seems to be a useful diagnostic tool in thoracic outlet syndrome. Examination in abduction, which is feasible in an open scanner, is essential for the diagnosis.
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