Selective nerve root block has been known as a useful therapeutic measure for pain associated with herpes zoster. In this study we examined the correlation between the characteristics of pain and the efficacy of selective nerve root block by questionnaire sent to 40 patients who were treated with selective nerve root block using local anesthetic and betamethasone. Selective nerve root block was more effective in the patients whose pain was paroxysmal or shooting in its nature compared to those who had continuous and dull pain. Besides the characteristics of pain, the interval between the onset of the disease and block seemed to be a determinant of efficacy of block, the efficacy being better in the patients with an interval less than 3 months. However, neither the degree of sensory disturbance, age, nor degree of skin eruption showed correlation with the efficacy of block. Almost all the patients who exhibited final pain relief, reported that the characteristics of pain had been changed shortly after block. Change of characteristics of paroxysmal-shooting pain, rather than the reduction of the area and intensity of dull and continuous pain, seems to be a good predictor of eventual satisfaction of the patients.

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Several recent studies have been shown that central mechanisms such as abnormality of thalamic activity and hyperactivity of anterior cingulate cortex (ACC) and insula, are involved in the pathogenesis of CRPS type-1. A recent study has demonstrated the efficacy of electro-convulsive therapy (ECT) on neuropathic pain. Despite clinical reports of successful results, the effects of ECT on the regional cerebral blood flow (rCBF) have not been studied.
Purpose: The aim of the present study was to examine the efficacy of ECT in relieving pain in patients with CRPS and to characterize the effect of ECT on the rCBF in the thalamus, ACC and insula using Xenon-CT.
Methods: Three CRPS patients, who had failed to respond to standard pain treatment, received a course of ECT. We measured rCBF of thalamus, ACC, and insula of patients using Xenon-CT before and after ECT.
Results: ECT resulted in excellent resolution of pain in two patients. Both patients had significant decreases in rCBF of the thalamus ipsilateral to the side of pain and significant increases in rCBF of the ACC and the insula. Xenon-CT showed that significant left-right differences in rCBF of the thalamus were abolished after ECT in two responders.
Conclusion: This study suggested that normalization of significant left-right differences in rCBF of the thalamus is related to one of the analgesic mechanisms of ECT on CRPS type-1.

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A 50-year-old man with left-sided cluster headache (CH) was treated with stellate ganglion block (SGB). He had onset of episodic CH at age 41. Until 3 years ago, episodes of CH 1-2 attacks par day, had occurred every 12 months over 4 to 8 weeks. An attack carted for 30 to 60 minutes with tearing of the eye, nasal stuffiness and rhinorrhea. Three months ago, CH occurred for the first time in 3 years. The initially severe headache evolved into a series of discrete, severe, left-sided headaches of 90 to 120 minutes' duration that occurred 4 to 7 times a day. Associated symptoms included ipsilateral lacrimation, nasal congestion, rhinorrhea and conjunctival injection. This time he responded little to drug treatment including oxygen inhalation, ergotamine, verapamil, predonisolon, lithium carbonate, indomethacin, etc. Sumatriptan was not available in Japan at that time. The results of general physical and neurologic examinations were unremarkable. Brain MRI was normal. Left SGB with 4 to 6mL of 1 or 0.5% mepivacaine was carried out twice a week. A headache diary had been kept by the patient (Fig. 1). Right after the first SGB performed with 4mL of 0.5% mepivacaine, the frequency and duration of headache diminished by half. After the 9th SGB, the attacks of headache subsided. Sympathetic ipsilateral hypofunction in CH patients had been pointed out. Sympathetic activation is considered to be one of the triggers of CH. Repeated ipsilateral SGBs possibly suppressed sympathetic activation, reducing is headache attacks in this patient.

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Generally, post-extraction toothache does not persist for more than 24 hours. However, only a small number of patients develop pain and numbness for a long period. We experienced the management of two cases of complex regional pain syndrome (CRPS) after the extraction of a wisdom tooth.
Case 1: A 50-yr-old man complained of numbness and abnormal sensation around the left mental area after extraction of a wisdom tooth. Objective physical examinations revealed hypoesthesia and allodynia limited to the left maxillary region. Other neurological examinations including X-ray and magnetic resonance imaging detected no significant abnormalities. He received Super Lizer^TM irradiation to the left stellate ganglion and maxillary area followed by stellate ganglion block and oral amitriptyline and carbamazepine. After improving for a month, symptoms revived. Amitriptyline was changed to fluvoxamine, but it was not effective. Consequently, we referred him to the department of phychosomatic medicine, and he is now being followed.
Case 2: A 67-yr-old woman had abnormal sensation in the oral cavity and amblygeustia after a wisdom tooth extraction. Her symptoms were almost completely received with oral amitriptyline and Super Lizer^TM irradiation. Her symptoms recurred after a 6 months interval. Intravenous infusion of ketamine 20mg was begun at the outpatient clinic once a week after ketamine test. Five series of this therapy resulted in complete pain relief.
CRPS due to tooth extraction may deteriorat e quality of life, although it does not influence human life. Because this disease is iatrogenic, patients often are likely to reject invasive therapy. In such case, comprehensive therapies including small doses of ketamine infusion, laser irradiation and psychologic therapy are required for the improvement of such types of pain.

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Reported is a case of reflex sympathetic dystrophy (RSD) in a young girl after ankle joint injury. Intractable pain, all odynia, hyperalgesia, coldness, sweating, cyanosis and swelling developed, and she was diagnosed as having type I complex regional pain syndrome (stage III RSD). In thermography, the skin of the injured leg showed a low temperature. Although she received sympathetic nerve block including continuous epidural block and intravenous regional sympathetic block, several medications and rehabilitation, the relief of her symptoms was poor. After receiving psychogenic advise, such as, activities of daily school life, and rehabilitation for two years, she had a perfect recovery from the symptoms. The present case suggests that a psychogenic approach and rehabilitation is important in a child RSD case.

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Described are 2 cases of accidental Subarachnoidal injection of Neo Vitacain^® during lumbar epidural block.
The patients were referred to our clinic from the orthopedics clinic with the complaint of severe pain due to lumbar disc herniation. First, we performed several lumbar epidural blocks with 0.5% mepivacaine. However, the pain was relieved for only a couple of hours. Then we used Neo Vitacain^® instead of mepivacaine to prolong the effective time of the block. Although Neo Vitacain^® was injected after comfirming the negative aspiration of the cerebrospinal fluid, sensory and motor paralysis occurred 10min after the epidural block due to accidental subarachnoidal injection. A urethral catheter was inserted and placed for dysuria for 6 to 7 hours. The patients returned home 8 to 9 hours after the injection of Neo Vitacain^®.
In conclusion, We should pay greater attention to accidental subarachnoidal injection of Neo Vitacain^® during epidural block.

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Despite the high prevalence of migraine in Japanese, most patients with migraine are not diagnosed by physician, and therefore may not be adequately treated. Sumatriptan, a selective 5-HT_1B/1D receptor agonist, is used when attacks do not respond to ergotamine, or when intolerable side effects occur. We examined the efficacy of subcutaneous (SC) sumatriptan (3mg) for seven patients with migraine and a patient with SUNCT syndrome, which is characterized by short-lasting, unilateral neuralgiform headache attacks with conjunctival injection and tearing. We confirmed that sumatriptan SC had a significant improvement in all patients with migraine and provided relief as early as 10-30 minutes after administration, while a patient with SUNCT syndrome does not respond to the treatment. We also found that all patients who could be treated lived in the neighborhood of our clinic. No significant adverse events were observed except mild neck pain in two patients with migraine, and no patients experienced headache recurrence within 24 hours after administration. In conclusion, sumatriptan SC is recommended for acute treatment of migraine, however we should consider the route of administration of this drug (for example, oral tablets, intranasal and rectal formulations) as well as SC autoinjection formulation.

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