Diagnostic procedure symptomatic facet joint was designated according to pain referral. Also, medial branches were injected with 2% lidocaine 0.3 ml per site.

Treatment procedure The posterior technique was first described in 1995 . All interventions assessed the intravenous saline lock on arrival at the outpatient department using pulse oximetry and noninvasive blood pressure monitoring and intravenous sedation as required. Patients were assigned in a prone position under C-ARM fluoroscopic guidance with a Neurotherm NT 2000 Lesion Generator the (USA manufactured) . The electrode pad of the radiofrequency equipment was attached to the ipsilateral side of the posterior thigh. After the skin was then anesthetized with 1% lidocaine, a 20-gauge, 10-cm cannula with 10-mm curved active tip (Diros RF Cannula, Diros Technology Inc., Canada) was inserted along a 15 to 30 degree angle to the sagittal plane (slightly posterior oblique approach) . The cannula was applied until reaching the lateral part of the articular pillar . Then the depth of the cannula was checked using a lateral view. A probe was inserted through the cannula and linked to a radiofrequency generator (Diros Technology OWL, Canada). After impedance were accomplished at below 500 Ohm, sensory stimulation was performed at 50 Hz and the patient reported not feeling any tingling sensation along the distribution of dermatome. Consequently, a motor stimulation (2 Hz) was executed until multifidus twitching was presented at stimulation less than 1 volts and no motor twitching was observed along the myotome. A non-ionic contrast medium was injected to ensure the intravascular injection before 1% lidocaine 0.5 ml was injected after the needle reached the desired location. The study investigated two lesions due to the anatomical variation of the medial branches. Patients in the CRF group (n = 16) underwent CRF at 80°C for 90 seconds for 2 cycles. Patients in the CPRF group underwent CRF at 80°C for 90 seconds for 1 cycle followed by PRF at 42°C for 120 seconds for 1 cycle. 0.125% bupivacaine plus 2 mg of dexamethasone in a total volume of 1 mL were injected after lesioning had performed.

Measurement The demographic data including age, sex, comorbidities, body mass index (BMI), level of procedure, visual analog scale (VAS;1-100) Neck Pain Disability Index and complications were reviewed. It contains ten sectors: seven sectors related to everyday existing behaviors, two sectors correlated to pain, and one sector correlated to concentration. All items are marked from 0 to 5. A mark of 0 denotes the maximum level of function, while a mark of 5 indicates the bottom level of function. The maximum mark is 50, and a greater mark relates to an increased level of disability. The NDI scores were recorded before intervention and first month, third month, sixth month, ninth months and 12 months after intervention. The follow-up was performed either face to face or by phone, and patients were not permitted to use over-the counter analgesic medication. The primary outcome was number of patients who had successful treatment, expressed as at least 80% pain relief from baseline and NDI score less than 15 for at least 3 months . The secondary outcomes comprised the duration of pain relief defined as the time of pain relief until VAS had restored to at least 50% from baseline and side effects including numbness, ataxia, dysesthesia, hypersensitivity, itching and muscular weakness (dropped head syndrome) between group comparisons. A research assistant, who was uninvolved in the intervention or post-operative follow-up, collected all data in prospective medical records.