A Case of Intractable Occipital Neuralgia Successfully Treated by C2 Ganglion Block
Mingi Chan-Liao , Wang-Hin Yip, Chi-Lin Chuang*
Dept. of Anesthesia and Radiology*, Jen-Ai Hospital, Tali, Taichung, Taiwan
Occipital neuralgia is a benign extracranial cause of headache, and it may be mistaken for a variety of more serious headache syndromes, thus sometimes difficult to manage.We present a case with intractable occipital neuralgia which was successfully treated with C2 ganglion block.
A 46-year-old man was referred to our pain clinic for further investigation of his chronic headache. His unilateral headache was described as originated from the neck region and always extended to the area around his left eye. The pain was sometimes associated with tearing of the eye and nasal congestion on the left side but no tinnitus.
Drug therapy was ineffective but greater occipital nerve blockades and trigger point injections with a mixture of local anesthetic and corticosteroid always produced prompt but short-lived relief. Based on his lancinating pain in the distribution of the greater occipital nerve coupled with positive Tinel’s sign and temporary pain relief after local anesthetic injection, he was diagnosed as having occipital neuralgia. After initial improvement, no full remission could be achieved. So in view of the intractable nature of this pain, a CT-guided C2 ganglion block was scheduled on January 17, 1998. The procedure was carried out from a posterior approach according to Bogduk’s method1 modified by Yuda.2
The patient was placed prone on the CT table without sedation. The level of the C2 vertebra was identified using a scanogram(scout view). Then the optimum access to the intervertebral foramen, rather the space between the vertebral arch of C1 and C2 was chosen with the aid of sequential slices, avoiding the vertebral artery. A 23G spinal needle was inserted perpendicularly and about 2 cm from the midline and advanced 5 cm deep until the tip is about 5 mm behind the groove for the vertebral artery. Extreme care was taken to keep clear of the vertebral artery. Additional scans of adjacent levels were obtained to exclude a loop of the artery. As the needle tip hit the target, a paresthesia was elicited. After injection of 2% xylocaine 1.5 ml mixed with triamcinolone 0.5 ml, the pain completely subsided and the patient reported an area of numbness that corresponded with the distribution of the C2 dermatome. Scalp paresthesia also disappeared completely 3 days later. After the procedure the patient was free of pain for more than 2 months.
Several authors have described the clinical syndrome of occipital neuralgia. Occipital neuralgia is not an uncommon cause of protracted or severe intractable headache. The frequency of an attack can vary from weeks to months, and the duration of a headaches can vary from days to weeks.Because there are no specific laboratory or radiologic findings to confirm the diagnosis of occipital neuralgia, the diagnosis and treatment must rest on a careful and accurate history and physical examilnation. The best method of confirmation remains tenderness of the associated nerves, along with characteristic pain syndrome and relief of the symptoms with local anesthetic blockade of the associated nerve. Blockade of the greater or lesser occipital nerve with local anesthetic should provide prompt and sometimes sustained relief from the headache. Because these nerves do not supply intracranial structures, headaches that are relieved following nerve block are considered to be caused by extracranial factors.. .We established the diagnosis according to the International Headache Society’s diagnostic criteria.3 The possible causes of occipital neuralgia has been discussed elsewhere.,4 but it is important to consider other causes of occipital neuralgia as migraine and cluster headaches as well as diseases that involve the C!, C2 and C3 nerve roots may be easily confused.5 These roots receive branches from the spinal accessory nerve and the superior sympathetic ganglion. There is also communication between the roots and the trigeminal ganglion and probably the acoustic and vestibular nerves which may explain some of the confusing symptoms such as blurred vision, nasal stuffiness, tinnitus and dizziness.
Usually most of the patients having these disturbing symptoms report significant and temporary symptom relief within minutes of a local anesthetic injection. If long-lasting relief is not obtained, or when pain is refractory to conventional measures such as NSAIDs, physical therapy and repeat local blocks of the occipital nerve, some authors advocate even alcohol block of the nerve or radiofrequency thermocoagulation.6.7
If C2 radiculopathy is suspected as in this case, either C2 root block or C2 ganglion block under CT guidance may be indicated and carried out with ease. The result in our case demonstrated the efficacy of this treatment modality. If symptoms recur, the treatment may be repeated. The procedure can be done on an outpatient basis but is best performed with a thorough knowledge of neuroradiology.
Since occipital neuralgia is pathophysiologically seen as a cervico-occipito-trigeminal complex, C2 spinal ganglion block therefore is an effective interventional procedure to differentiate the complicated causes of occipital pain including C1-C3 root lesions as well as to treat C2 radiculopathy and the so-called cervicogenic headaches..
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2. Yuda Y. Technique of nerve block-a new approach to pain in the head, neck and back. Jikeikai Med J 1990;37:499-513
3. Headache classification Committee of the International Headache Society. Classification and diagnostic criteria for headache disorders, cranial neuralgias and facial pain. Cephalalgia 1988;8:61-71
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6. Mathur JG. Treatment of occipital neuralgia (letter). J Aust 1980;26:102
7. Kepplinger B, Papst H, Schrottner O, Zaunbauer F. Radiofrequency thermal coagulation of the greater occipital nerve. In: Pain-Clinicl Aspects and Therapeutical Issues. Part I, Eds: B. Kepplinger. Selva 1992;59-60