A systematic review of diagnostic utility of selective nerve root blocks.

BACKGROUND Transforaminal epidural injections, or selective nerve root blocks, are used for a myriad of different spinal disorders. A clear consensus on the use of selective nerve root injections as a diagnostic tool does not currently exist. Additionally, the effectiveness of this procedure as a diagnostic tool is not clear. OBJECTIVE The objective was to evaluate the accuracy of selective nerve root injections in diagnosing spinal disorders. STUDY DESIGN The study involved a systematic review of diagnostic studies about selective nerve root blocks for the diagnosis of spinal pain. METHODS A systematic review of the literature for clinical studies was performed to assess the accuracy of selective nerve root injections in diagnosing spinal disorders. Methodologic quality evaluation was performed utilizing AHRQ and QUADAS criteria. The methodology of the studies was graded and the evidence was classified into five levels: conclusive, strong, moderate, limited, or indeterminate. RESULTS There is limited evidence on the effectiveness of selective nerve root injections as a diagnostic tool in spinal disorder. There is insufficient research into this area for strong support, but the available literature is supportive of selective nerve root injections as a diagnostic test in equivocal radicular pain. The current analysis provides moderate evidence of transforaminal epidural injections in the preoperative evaluation of patients with negative or inconclusive imaging studies. CONCLUSIONS Selective nerve root injections may be helpful as a diagnostic addition in evaluating spinal disorders with radicular features, but the role of this diagnostic test needs to be further clarified by additional research and consensus on technique.