A Single-Blind, Prospective, Randomised Control Trial Comparing Two Radiofrequency Neurotomy (RFN) Techniques For the Treatment of Chronic Lower Back Pain Originating from Facet Joints

Radiofrequency Neurotomy (RFN) is a treatment that has been available for many years for facet joint pain following appropriate diagnosis with facet joint injections or medial branch blocks. If facet joints are the sole cause of pain, RFN may provide total pain relief. If they are a contributing cause, partial relief may be provided. The procedure involves applying radiofrequency to the nerve for a short period of time. The details for each study arm are provided below. This procedure is performed in a hospital environment (ie in surgery) under anaesthetic. . Anatomical Thermal RFN: This procedure follows the International Spine Intervention Society (SIS) Guidelines.15 Prior to the procedure, a deep paravertebral block with 1% xylocaine is performed. The C-arm Fluoroscope is aligned in the AP decline view, and 15-20°C ipsilateral oblique to the level in question and 100-mm 16G RFK needles with 10-mm sharp active tips are laid parallel to the course of the index medial branches under fluoroscopic vision to perform the radiofrequency neurotomy. Careful view is to be taken to show the uninsulated tip lies opposite the middle two fourths of the neck of the superior articular facet. Three lesions are made at each medial branch by gradually increasing the temperature at about one degree per second until 80-85°C is reached. That temperature is maintained for 90 seconds. Post procedure Naropin 0.75% is injected at the neurotomy sites. Generic RFN A C-arm image intensifier is positioned in a slightly (10–15°) oblique position, with the patient in prone position. A 22G SMK needle with a 10-mm active curved tip is introduced at each entry point. The position of the cannula is checked on the lateral and anteroposterior projection. The depth is adjusted until the tip of the cannula is at the level of a line connecting the posterior aspects of the intervertebral foramen. Sensory stimulation (50Hz) is positive when the patient feels paresthesia, and motor stimulation (2Hz) is positive with visible muscle stimulation but no leg contractions. Once the position of the electrode is satisfactory, 1-2 mL per level of 2% lidocaine is injected and a 90°C 90 seconds radiofrequency lesion is made of the medial ramus dorsalis of L3-4, L4-5, and L5-S1. The procedures will be performed by pain physicians and/or pain specialists and the patients will be 'repeat' patients who have previously benefited from RFN treatment and seek re-treatment. Re-treatment is often required because the nerve usually recovers over time (typically after 12 months or more) from this treatment. As the nerve recovers, sometimes the pain also returns. The treatment will be a single procedure in each study arm. If the procedure is not successful, the patient will be offered the alternative treatment of the other study arm. The patients will complete questionnaires at various time points over a 12 month period to assess their pain levels at various intervals following the procedure. A summary of the patients' visits is provided below: Visit 1 - screening/enrolement Visit 2 - RFN procedure (hospital) 1 month pain assessment (postage/email of pain diary for completion and return) Visit 3 - 2 month follow up including pain assessment (patient offered alternative treatment if initial outcome unsatisfactory). Options: Group A - successful treatment (obtaining 50% or more pain relief), Group B - unsuccessful pain relief, patient offered and accepted to have alternative procedure, or Group C - unsuccessful pain relief, patient offered but did not accept to have alternative procedure. Note that unsuccessful pain relief is defined as obtaining less than 50% pain relief. Visit 4A - 6 months post procedure follow up including pain assessment Visit 5A - 12 months post procedure follow up including pain assessment Visit 4B - alternative RFN procedure (hospital) B - 1 month pain assessment postage/email of pain diary for completion and return) Visit 5B - 2 month follow up including pain assessment Visit 6B - 6 months post procedure follow up including pain assessment Visit 7B - 12 months post procedure follow up including pain assessment