Lumbar zygapophysial (facet) joint radiofrequency denervation success as a function of pain relief during diagnostic medial branch blocks: a multicenter analysis.
BACKGROUND
The publication of several recent studies showing minimal benefit for radiofrequency (RF) lumbar zygapophysial (l-z) joint denervation have led many investigators to reevaluate selection criteria. One controversial explanation for these findings is that the most commonly used cutoff value for selecting patients for l-z (facet) joint RF denervation, greater than 50% pain relief after diagnostic blocks, is too low and hence responsible for the high failure rate.


OBJECTIVE
To compare l-z joint RF denervation success rates between the conventional greater than or equal to 50% pain relief threshold and the more stringently proposed greater than or equal to 80% cutoff for diagnostic medial branch blocks (MBB).


METHODS
Multicenter, retrospective clinical data analysis.


METHODS
Two hundred and sixty-two patients with chronic low back pain who underwent l-z RF denervation at three pain clinics.


METHODS
Outcome measures were greater than 50% pain relief based on visual analog scale or numerical pain rating score after RF denervation persisting at least 6 months postprocedure, and global perceived effect (GPE), which considered pain relief, satisfaction and functional improvement.


METHODS
Data were garnered at three centers on 262 patients who underwent l-z RF denervation after obtaining greater than or equal to 50% pain relief after diagnostic MBB. Subjects were separated into those who received partial (greater than or equal to 50% but less than 80%) and near-complete (greater than or equal to 80%) pain relief from the MBB. Outcomes between groups were compared with multivariate analysis after controlling for 14 demographic and clinical variables.


RESULTS
One hundred and forty-five patients obtained greater than or equal to 50% but less than 80% pain relief after diagnostic MBB, and 117 patients obtained greater than or equal to 80% relief. In the greater than or equal to 50% group, success rates were 52% and 67% based on pain relief and GPE, respectively. Among patients who experienced greater than 80% relief from diagnostic blocks, 56% obtained greater than or equal to 50% relief from RF denervation and 66% had a positive GPE.


CONCLUSIONS
Using more stringent pain relief criteria when selecting patients for l-z joint RF denervation is unlikely to improve success rates, and may lead to misdiagnosis and withholding a potentially valuable treatment from good candidates.
Pain Management Division, Department of Anesthesiology & Critical Care Medicine, Johns Hopkins School of Medicine, 550 North Broadway, Suite 301, Baltimore, MD 21029, USA. scohen40@jhmi.edu
Steven P
SP
Cohen
Milan P
MP
Stojanovic
Matthew
M
Crooks
Peter
P
Kim
Rolf K
RK
Schmidt
Cynthia H
CH
Shields
Scott
S
Croll
Robert W
RW
Hurley
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000779:Anesthetics, Local / Q000627:therapeutic use; D003714:Denervation / Q000379:methods; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000188:drug therapy / Q000532:radiotherapy*; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D018579:Patient Selection; D021801:Zygapophyseal Joint / Q000294:innervation / Q000528:radiation effects*
D000779:Anesthetics, Local