Articles: nerve-block.
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A new technique of sciatic nerve block in the popliteal fossa was evaluated in 120 patients using an 18 s.w.g. cannula. Precise placement of the cannula was facilitated with the aid of a nerve stimulator. In addition to an initial dose of 1% prilocaine with adrenaline 1: 200,000 (5 mg kg-1), 5 mL 0.5% bupivacaine was used for blockade of the saphenous nerve distal to the medial tibial condyle. ⋯ Satisfactory anaesthesia was achieved in 117 patients (97.5%); two patients required general anaesthesia, since repositioning of the cannula after initial application of local anaesthetic was strictly avoided. No post-operative complications relating to the nerve block were observed. This technique of sciatic nerve block in the popliteal fossa provides effective and safe anaesthesia of the lower leg.
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The efficacy of different techniques of facial nerve block for cataract surgery was investigated. Forty four patients underwent either modified O'Brien, Atkinson, van Lint, or lid blocks. Intentional muscle activity of the orbicularis oculi muscle was recorded and the area under the EMG curve calculated for quantitative comparison of muscle activity between the groups before and after injection of lignocaine with the vasoconstrictor naphazoline nitrate. ⋯ The lid block, on the other hand, affected terminal branches of the facial nerve's temporal division. In this study, complete lid akinesia was achieved by both the modified O'Brien block and the lid block. However, because the modified O'Brien block involves the risk of neural injury to the facial nerve or its main divisions, the lid block is recommended as the most effective and safe method to achieve akinesia of the orbicularis oculi muscle.
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Six patients undergoing paravertebral blocks for chronically painful conditions of the chest wall were thermographically imaged so that the extent of cutaneous vasodilatation and hence sympathetic block could be correlated with the distribution of the somatic block. All blocks were performed by a single experienced operator, with a single percutaneous entry, using 15 ml of 0.5% bupivacaine at a mean level of T9-10 (range T7-8--T10-11), with radiological confirmation of correct needle placement. There was a mean distribution of the somatic block of five dermatomes (range 1-8), as evidenced by loss of pinprick sensation, with upper and lower limits of T6 and L3. ⋯ No significant postural changes in blood pressures were seen, although there was a small but significant decrease in supine heart rate (p = 0.05). This study demonstrates that a large unilateral somatic and sympathetic block is obtainable with a single thoracic percutaneous paravertebral injection. It challenges the suggestions that this method of analgesia is ineffective and hazardous, that a sympathetic component is a rare accompaniment and that the lumbar nerve roots are spared.