This is a recently updated & comprehensive article -- see the abstract and link below.
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From Lumbosacral Facet Syndrome, Sports Medicine

An alternative to medial branch block denervation for lumbosacral facet syndrome

Fluoroscopically guided medial branch nerve injections are often used for diagnostic purposes to determine whether a zygapophyseal (Z) joint in question is responsible for a patient’s low back pain. An alternative to medial branch block denervation for lumbosacral facet syndrome may be laser denervation to the dorsal surface of the facet capsule.

http://www.emedicine.com/sports/TOPIC65.HTM#laserdenerv