Degenerative scoliosis is a complex disorder. The primary surgical aims are to decompress the neural elements, normalize both sagittal balance and coronal and rotational deformity, fixate to the sacrum/ilium when appropriate, and optimize conditions for osteogenesis and fusion.

Blocks of greater depth and longer duration result from injection of smaller volumes and, correspondingly, higher lidocaine concentrations containing the same dose. The corollary is that lower lidocaine doses are required to achieve the same effect when smaller volumes are injected. Curiously, when the equivalent E50 is injected, total drug taken into the nerve is less from the smaller volumes than from the larger volumes, even though the peak functional effects are equal. Total intraneural local anesthetic may not represent the effective drug in the compartment that contains nerve axons, the actual location of neural blockade.