Hypotension in Spinal Anesthesia for Total Knee Joint Arthroplasty: a Comparison of Taylor's Approach With Paramedian Lumbar Approach

1. Purpose

To determine if Taylor's approach (paramedian, via L5-S1 interspace) to subarachnoid blockade produces less hypotension than the more commonly used paramedian lumbar approach (via L3-L4 interspace). 2. Hypothesis

Taylor's approach to subarachnoid blockade for total knee joint arthroplasty will result in less hypotension which requires treatment than a paramedian lumbar approach. 3. Justification

Taylor described a method of obtaining spinal anesthesia for urological procedures using a paramedian approach to L5-S1. This interspace is large and tends to be less affected by degenerative changes than the lumbar interspaces. Because of these attributes this approach can be used as an alternative to either midline or paramedian approaches to the lumbar vertebrae interspaces.

Hypotension is a frequent and important complication of spinal anesthesia. As the degree of hypotension correlates with the height of blockade achieved, performing the dural puncture at a lower interspace may result in less hypotension. Several previous studies have compared the degree of hypotension resulting from a subarachnoid block performed via different lumbar interspaces with conflicting results. However a direct comparison of the lower Taylor's approach with a lumbar approach has not been investigated previously.