A DIRECTIONAL NEEDLE IMPROVES EFFECTIVENESS AND REDUCES COMPLICATIONSOF MICROCATHETER CONTINUOUS SPINAL-ANESTHESIA

The present prospective randomized study compares the impact of two di fferent spinal needle designs - non-directional versus directional - o n the effectiveness of continuous spinal anaesthesia provided via a mi crocatheter in orthopaedic patients. Using the midline approach, a 28- gauge spinal catheter was inserted either through a 22-gauge Quincke n eedle (non-directional, Group 1, n = 21) or a 22-gauge Sprotte needle (directional, Group 2, n = 21) under standardized conditions. The inci dence of technical difficulties and postoperative complaints, onset ti me of analgesia at the level of T-10 and dose requirement of plain bup ivacaine 0.5% were recorded. Postoperatively, the subarachnoid positio n of the catheters was radiographically evaluated. There was a higher incidence of technical problems during catheter insertion in Group I c ompared with Group 2 (71% VS 19%, P< 0.05) Onset time of analgesia was shorter (P < 0.05) and anaesthetic dose requirement was lower in pati ents in Group 2 than in Group 1. While 40% of the catheters were found in a caudal position in Group 1, all catheters were in a cranial posi tion or at the level of the puncture site in Group 2 (P < 0.05). There was no difference in the incidence of postoperative complaints betwee n the groups. The faster onset of analgesia and lower dose requirement of local anaesthetics associated with a lower incidence of technical problems suggest that there is greater effectiveness and safely when m icrocatheters are inserted using directional needles rather than non-d irectional needles.