,At this point, I then attempted lumbar puncture by making a small incision with an 11 blade in the L4 interspinous space and then later in the L3 interspinous space and attempted to puncture the dural sac with the Tuohy needle. 
,At this point , I then attempted lumbar puncture by making a small incision with an 11 blade in the L4 interspinous space and then later in the L3 interspinous space and attempted to puncture the dural sac with the Tuohy needle .