Continuous Spinal Anesthesia Versus Epidural Anesthesia in Geriatric

60 patients aged older than 60 years, American Society of Anesthesiologists (ASA) class II or III and scheduled for major hip surgery will be randomized, in to two groups anesthetized using continuous spinal anesthesia or using continuous epidural anesthesia. In continuous spinal anesthesia group 22 G catheter with priming volume0.1m The Catheter will be then fed over the needle into the intrathecal space and Inserted 3cm cephalad into the subarachnoid space.The spinal needle and the modified Tuohy needle will be then removed, and a Luer connector and A filter previously filled with the anesthetic solution will be attached to the Catheter (priming volume 0.6ml). Plain bupivacaine 0.5% in 20ml vials will Be used CSA group received 1 ml(5 mg) of plain bupivacaine (0.5%) Together with fentanyl l25μg injected via the catheter at a rate of 0.2ml/15s. The level of the resulting sensory blockade will be tested using pin prick. Continuous epidural anesthesia Group A Perifix 401filter epidural set.It is composed of Tuohy epidural needle1.3×80 mm (18G);an epidural catheter with three lateral openings 0.85×0.45×1000 mm (20G); loss-of-resistance syringe, 10 ml; a Perifix flat filter 0.2μm; and Perifix screw connector. The needle is advanced until the epidural space is identified by the loss-of-resistance technique, and then a 20G catheter is inserted 3 cm cephalad into the epidural spac e. a test dose of 3ml of 2% lignocaine with adrenaline (1:200000) will be injected into the catheter. Three minutes later, 10 ml of plain bupivacaine (0.5%) together with fentanyl l50μg will be injected via the catheter. If the sensory blockade don't reach T10 within 20 min of the administration of the initial dose, additional doses of 5 ml of plain bupivacaine 0.5% will be injected epidurally every10 min until the level of T10 or amaximum of 25 ml of plain bupivacaine 0.5 % will be achieved. If the sensory blockade don't not reach T10, anesthetic failure will be considered, and the patients will be excluded from the study.