Sensory Mapping of Lumbar Facet Joint Pain

Intraoperatively, radiofrequency needles will be placed on specific nerves targeted using parallel needle placement technique under image guidance. These nerves will have identified by the diagnostic injections carried out previously. The nerves will be located using 50 Hz sensory stimulation. The targeted medial branches (dorsal ramus in the case of L5) will be stimulated using suprathreshold stimulation (up to three times the sensory detection threshold) to identify the pain referral area. Motor stimulation of 2 Hz will be used to identify the multifidus muscle as well as to evaluate the close proximity to major spinal nerve to improve the safety of the procedure.