where do spinal catheters go?
The purpose of this study was to investigate the incidence of technical problems encountered when performing continuous spinal anesthesia and the influence of catheter tip position on block height following injection of a hypobaric spinal anesthetic. Twenty-nine elderly patients undergoing hip surgery were studied. Lumbar puncture was performed with an 18-gauge Tuohy needle at the L3-4 (or L2-3) interspace. Threading was defined as easy if a 20-gauge catheter was inserted on the first try, 3-4 cm cephalad. Threading was considered difficult if cephalad insertion of the catheter was impossible on the first try; the Tuohy needle was then rotated with its bevel facing caudally, the catheter inserted for 1-2 mm, and the needle turned back cephalad together with the catheter partially threaded, for further cephalad insertion up to 4 cm. All patients received 7.5 mg of hypobaric bupivacaine or tetracaine in the lateral decubitus position and sensory levels were determined by pinprick. After
