RF Neurotomy in Chronic Cervicogenic Headache Table 1. Major criteria for diagnosis of cervicogenic headache Table 2. Characteristics of study subjects I. Unilateral headache without side shift II. Symptoms and signs of neck involvement: a. Provocation of attacks: 1. Pain triggered by neck movement and/or sustained awkward head position 2. Pain similar in distribution and character to the spontaneously occurring pain elicited by external pressure over ipsilateral upper, posterior neck region or occipital region b. Ipsilateral neck, shoulder and arm pain of a rather vague, non-ra- dicular nature c. Reduced range of motion in the cervical spine Characteristics Sex (men:women) Mean age Preoperative VAS No. of patients showed pain relief by greater than 75% 1 week 1 month 6 months 12 months Average number of headache-day/week (mean) Preoperative Postoperative Reduction of analgesic intake/week VAS, Visual Analogue Scale. 327 16:14 54 yrs 6.8 18 (60.0%) 25 (83.3%) 23 (76.7%) 22 (73.3%) 6.2 2.8 70% Fig. 1. The target point and C3-C4 lesioning. A point of intersec- tion of 2 lines diagonally drawn from supero-anterior and supero- posterior to infero-posterior and infero-anterior articular pillar. cedures were monitored by repeated radiographic screening with a C-arm image intensifier. Percutaneous RF neuroto- my was performed under aseptic conditions, with the patient lying in the prone position. No sedation or systemic analgesic was used. The electrode was inserted parallel to the medial branch of the C3-C4 facet joint with a percutaneously pos- terolateral approach along a parasagittal plane, tangential to the lateral margin of the articular pillar, and was directed toward the target point under repeated C-arm image inten- sifier screening. The target point was a point of intersection of 2 lines diagonally drawn from supero-anterior and supero- posterior to infero-posterior and infero-anterior articular pil- lar. The levels of lesioning were C3-C4 (Fig. 1). When the target point was reached, the position of the electrode was confirmed and recorded on anteroposterior and lateral films. Correct position was verified by stimulating current for both sensory and motor threshold. Usual thresholds for these were 0.3-0.9 V and 0.6-1.8 V, respectively. The target nerve was then anesthetized by the injection of 0.5 mL of 1% lidocaine before lesion production. Final lesion was generated at 80℃ for 90 sec. The average operative time was 19 min. Patients were discharged from the hospital after 1 to 2 hr of moni- toring to see whether there were any discomforts or signs of complications. Follow-up visits were made at 1 week, 1 month, 6 months, and at 12 months. The followings were taken as outcome parameters: Visual Analogue Scale (VAS), number of headache-days per week and amount of analgesic intake per week. Results were defined as successful if preoperative pain was relieved by more than 75%. RESULTS All patients well tolerated the procedure without additional analgesics or anesthetics. Eighteen (60%), 25 (83.3%), 23 (76.7%), and 22 (73.3%) patients showed pain relief by greater than 75% at 1 week, 1 month, 6 months, and at 12 months, respectively (Table 2). The average headache-days per week decreased from 6.2 days to 2.8 days, and the average analgesic intake per week showed a 70% reduction. There were no major complications related to the procedures. However, atax- ia was seen in 4 patients immediately after the procedure, which was resolved completely within a few hours to 2 or 3 days. Three patients obtained short-lasting relief (3 months). None of the patients reported cutaneous numbness, dyses- thesia, or worsening of pain. However, 12 patients compla- ined of soreness on the posterior neck for 2-7 days following the procedures. These possible side effects were preoperatively explained to all patients and no specific measures were nec- essary except temporary oral analgesics for 2-5 days postop- eratively. All such symptoms disappeared within a week. Interestingly, most of the patients showed definitive improve- ment after at least 2-4 weeks following the procedures. There were no instances of postoperative infection or other compli- cations related to the procedures. DISCUSSION The term ‘‘cervicogenic headache’’ is denoted for the hea- dache that originates from disorders of the neck (1). How-