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Radiofrequency denervation of the lumbar zygapophysial joints: 10-year prospective clinical audit.

BACKGROUND
Evidence for the efficacy of zygapophysial joint nerve radiofrequency neurotomy has remained controversial. Two randomized controlled trials showed positive results, but two others demonstrated no benefit. One carefully performed prospective trial confirmed high efficacy and lasting pain relief after the procedure; however, selection criteria for this study were superfluous, which resulted in a small number of patients available for follow up.


OBJECTIVES
A large clinical audit with routine patient selection and use of appropriate technique was undertaken to determine the effect of radiofrequency neurotomy of the lumbar facet joints for relief of chronic low back pain.


DESIGN
Prospective clinical audit for quality was conducted in the pain clinic affiliated with a tertiary care teaching hospital.


SETTING
An interventional pain management setting in Canada.


METHODS
All patients with low back pain of more than 6 months' duration, with or without non-radicular radiation to the buttock, hip, and leg were included. From January 1991 to December 2000, eligible patients underwent standardized diagnostic work-up, which included a self-reported pain questionnaire, physical examination, review of imaging studies, and diagnostic blockades. Those with an appropriate response to comparative double diagnostic blocks underwent standardized radiofrequency denervation of the lumbar zygapophysial joints. Patients were asked to estimate total perceived pain reduction (on a scale from 0% to 100%) at 6 weeks and at 6, 12, and 24 months after the procedure.


RESULTS
Of the 209 patients, 174 completed the study, and 35 were lost to follow-up or did not provide complete data for assessment. Of the 174 patients with complete data, 55 (31.6%) experienced no benefit from the procedure. One hundred and nineteen patients (68.4%) had good (> 50%) to excellent (> 80%) pain relief lasting from 6 to 24 months.


CONCLUSION
This large, prospective clinical audit indicates that proper patient selection and anatomically correct radiofrequency denervation of the lumbar zygapophysial joints provide long-term pain relief in a routine clinical setting.