[A comparison between midline and paramedian approaches for combined spinal-epidural anesthesia]

We compared midline approach with paramedian approach for combined spinal-epidural anesthesia (CSEA) by needle through needle technique. Seventy patients undergoing elective gynecological surgery received CSEA with a 27 G Whitacre spinal needle, which protrudes 12 mm beyond the tip of the Tuohy needle. The successful subarachnoid puncture with first attempt was noted in 33 patients (94%) of midline group (M group), in 31 patients (89%) of paramedian group (P group). At the subarachnoid puncture, skin to epidural space distance (43.2 mm vs 53.4 mm) and protrusion length of spinal needle (5.5 mm vs 8 mm) were significantly longer in the P group than in the M group. Abdominal radiography revealed the flexion of epidural catheter in 19 patients (54%) of M group and in 2 patients (6%) of P group. The choice of midline or paramedian approach for CSEA did not affect the success rate of the subarachnoid puncture, but paramedian approach required longer protrusion length of the spinal needle than midline approach. To raise the success rate of subarachnoid puncture by paramedian approach, a long protruded spinal needle is recommended.