Advantages of the paramedian approach for lumbar epidural analgesia with catheter technique. A clinical comparison between midline and paramedian approaches.

Forty-nine patients, scheduled for transurethral resection of the prostate or a bladder neoplasm on 50 occasions, were studied. The patients were randomly allocated to one of the two methods of puncture, midline or paramedian. Technical difficulties and the occurrence of complications were recorded. The extent of sensory and motor blockade was also compared. The paramedian approach was associated with a lower frequency of technical problems compared to the midline approach. Statistically significant differences were demonstrated between the two techniques for the following factors: repeated attempts at needle insertion; difficulty in identification of the epidural space; resistance to introduction of the catheter; resistance to injection through the epidural catheter; and the production of paraesthesiae (nine patients in the midline group compared to only one patient in the paramedian group, p less than 0.01). The catheter entered a vessel at first in two patients in each group. No significant differences were demonstrated between the groups in the extent of sensory and motor blockade. The study supports the view that the paramedian approach has technical advantages over the midline approach for lumbar epidural analgesia with catheter technique.