328 ever, it is not a detailed description and is still controversial whether use of this term is appropriate as two currently major international organizations relevant to head pain, namely, the International Headache Society (IHS) and International Association for the Study of Pain (IASP), disagree with the view point (7, 8). Symptoms and signs of cervicogenic headache such as me- chanical precipitation of attacks imply involvement of the neck. A reliable diagnosis of cervicogenic headache can be made based on the criteria established in 1990 and 1998 by the Cervicogenic Headache International Study Group (3, 4). Currently, positive response after an appropriate nerve block is an essential diagnostic feature of the disorder. Pathologic conditions such as fractures, congenital abnor- malities, bone tumors, rheumatoid arthritis, whiplash injury, and/or other distinct pathologies all may be related to the development of cervicogenic headache, but most authors be- lieve that these conditions should be described as underlying pathologies, and those without definitive structural patholo- gies should only be regarded as primary cervicogenic heada- che. The authors used the diagnostic criteria from 1990 (3) as the clinical diagnostic tool, and confirmed the diagnosis by C3-C4 cervical medial branch block. Some authors rec- ommend that when the diagnosis of cervicogenic headache is suspected, attempts should be made to confirm the diag- nosis with the objective tests of cervical facet block and C2 nerve diagnostic blocks (4, 8, 9). Although many cervical structures are suggested as the cause of cervicogenic headache, most authors agree that upper cervical nerves are the main cause. Among the upper cervical structures, we believe that C3-C4 cervical medial branches are the main culprit. Based on anatomical innervation of these branches to the upper cervical and occipital region, these may cause neck pain and radiating pain to the posterior and temporal areas of the head. Bovim et al. reported that C2 nerve block seemed to be the most informative procedure and C4 and C5 nerve block was of little value in the work-up of cervicogenic headaches (9). Stovner et al. reported that RF neurotomy of facet joints C2- C6 was not beneficial in cervicogenic headache in a random- ized, double-blind, sham-controlled study (10). Other stud- ies have shown what can be achieved if patients are carefully selected, using objective criteria under controlled conditions, and if meticulous surgical technique is used (6, 11-14). In a recent report of randomized controlled trial of treatment for cervicogenic headache (15), the authors did not find evidence that RF treatment of cervical facet joints and upper dorsal root ganglions was a better treatment than other conserva- tive management. And in a recent review, Martelletti and van Suijlekom (16) concluded that a consensus on a standard treatment for cervicogenic headache does not exist because of the great variability in patient selection and clinical effects. Anatomically, the cervical zygapophyseal joints are inner- vated by articular branches derived from the medial branch- es of the cervical dorsal rami (17). The C4-C8 dorsal rami J.B. Lee, J.Y. Park, J. Park, et al. arise from their respective spinal nerves just outside the inter- vertebral foramina and pass dorsally over the root of the ipsi- segmental transverse process. The medial branches of the typ- ical cervical dorsal rami are small (diameter, approximately 1 mm) and curve medially, hugging the waists of their ipsi- segmental articular pillars, covered by the tendinous slips of the origin of the semispinalis capitis. Each typical cervical zygapophyseal joint receives a dual innervation, from the medial branch above and from the medial branch below its location. The medial branches of the C3 dorsal ramus differ in their anatomy from those of lower cervical levels. A deep medial branch passes around the waist of the C3 articular pillar in a manner analogous to that of typical medial branch- es; this branch participates in the innervation of the C3-C4 zygapophyseal joint. The superficial medial branch of C3 is large (diameter, approximately 1.5-2.0 mm) and is known as the third occipital nerve. It winds around the lateral aspect and then the posterior aspect of the C2-C3 zygapophyseal joint. Articular branches may also arise from a communicat- ing loop that crosses the back of the joint between the third occipital nerve and the C2 dorsal ramus (17). Beyond the C2- C3 zygapophyseal joint, the third occipital nerve furnishes muscle branches to the semispinalis capitis and becomes cuta- neous over the suboccipital region. In this respect, the C3 dor- sal ramus is the only cervical dorsal ramus below C2 that reg- ularly has a cutaneous distribution. Those from C4 to C7 typi- cally lack any cutaneous branches (17). Therefore, on anato- mical grounds, pain suspiciously resulting from the C2-C3 levels can be blocked by coagulating the ipsilateral third occipi- tal nerve as it crosses the lateral aspect of the joint, and pain stemming below C2-C3 can be blocked by coagulating the cervical medial branches as they pass around the waists of the articular pillars above and below (18). During the last decade, percutaneous RF neurotomy has been increasingly used in the treatment of chronic cervical pain and cervicobrachial pain. The rationale for this technique is that nociceptive transmission from the cervical zygapophy- seal joint and muscles as well as ligaments can be blocked by coagulating the medial branches of the dorsal rami that innervate these structures (17, 18). At typical cervical levels, RF neurotomy achieves complete relief of pain, provided that patients have had complete relief of pain following diagnos- tic blocks for chronic cervical zygapophyseal joint pain (5, 17). Those blocks can be placebo-controlled or comparative local anesthetic blocks (11, 12). Similarly, for patients with headache mediated by the third occipital nerve, complete relief of pain can be achieved if meticulous and demanding techniques are followed (13). Because of many possible eti- ologies in cervicogenic headache, however, we believe that complete relief of pain is difficult to achieve, especially in chronic cases. Also, many authors agree that RF denervation of the C2-C3 facet joint procedure is technically difficult and does not guarantee good outcome (10, 17). Having these factors in mind, we selected the patients with C3-C4 cervi-