The plastic changes of peripheral and central nervous system have been examined extensively in animal models of chronic pain. A variety of neurotransmitters, neuromodulators, neurotrophic factors and their receptors exhibit dynamic changes in the chronic pain conditions, and the changes of these molecules are suggested to have important roles in the pathomechanisms of chronic pain.
In the chronic pain, a cancer pain is supposed to include almost all aspects of pain mechanisms. Three key categories, such as nociceptive pain, neuropathic pain and psychological pain, are most important when we consider the pathomechanisms of cancer pain. In this paper the two important molecular mechanisms of cancer pain, nociceptive pain and neuropathic pain are discussed.

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Objective pathophysiological study for osteoarthropathy of the knee was conducted using thermography in conjunction with the subjective responses of 69 patients (18 males and 51 females, mean age 71.6 years).
Active magnets and dummy magnets were randomly assigned to the patients in a double blind test. Active magnets were applied externally on the painful portion using samarium-cobalt (Sm-Co) magnets (180 mTesla, 5.2mm∅×2.5mm in height).
Dummy magnets (10 mTesla) were also applied externally, at random, as placebo.
All the patients wore 8-10 pieces of magnets for a 3 week period, after which the magnets were removed.
Before the treatment, in general, the lowest temperatures of the patients were lower than those of the healthy subjects.
Subjective and objective symptoms improved markedly 1 week after the application of the active magnets.
The lowest degrees of skin temperatures in the painful portions were significantly increased by exposure to active magnets 3 weeks after the application.
These findings suggest that the static magnetic fields might gradually increase blood circulation in ischemic conditions in osteoarthropathy of the knee.

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The cause of facial palsy is thought to be due to peripheral circulatory disturbance, polyneuropathy, and immunological features, yet the conclusion is still debatable. We consider whether or not SSR could be a new, non-invasive electrophysiological technique for assessing sympathetic functions. The aim of this study is to investigate the relationship between facial palsy and sympathetic dysfunction and to evaluate the prognosis of a facial palsy patient by SSR.
SSR was carried out in 35 peripheral facial nerve palsy patients. We have classified those patients treated by SGB for 20 times into two groups, GI and GII. GI scored more than 20 points (full score is 40) and GII scored less than 20. Pairs of surface electrodes were placed on the bilateral palms and backs of the hands. SSR was evoked by magnetic single stimulation of the median nerve at the wrist. Differences of amplitude and latency between the intact side and the palsy side were investigated. The significant differences of sympathetic function between left and right side (amplitude) were more than 30%.
Differences of SSR amplitude between left and right side were seen in both GI and GII in the early periods. Differences disappeared according to increase in facial palsy score of GI. However, GII showed significant differences between left and right side and showed less recovery of facial palsy scores. The period of treatment in GI was 45±15 and GE was 240±60 days, respectively (mean±SD, p<0.05).
These results suggest that SSR is maybe a valuable method to assess the sympathetic function and could be a parameter for anticipating prognosis.

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A 26-year-old man had an appendectomy under spinal anesthesia. The prognosis of the operation was uneventful, however the patient suffered a post spinal headache after surgery. He was given a mixture of antipyretic analgesics (nonsteroidal anti-inflammatory drugs). After disappearance of the post spinal headache (12 days after the operation), he went on a one-day excursion to a high mountain (about 2, 500 meters high) by a vehicle. In the evening, he had a buzzing in his ears, vertigo and headache. Next day, he consulted a neurosurgeon. The cause of his headache was diagnosed as a low-pressure syndrome by findings of the computed tomogram and acute bilateral hearing disorder in the low-pitched sound by findings of audiogram. These symptoms were like those of Meniere's disease. Seven days after routine therapy for Meniere's disease, these symptoms gradually disappeared. Vertigo disappeared in the early phase, and then headache and buzzing also disappeared. The character of the headache changed from dull pain to head heaviness. It is well known that a cause of post-spinal headache is a decrease in the intracranial pressure and the dilatation of intracranial veins by leakage of cerebro-spinal fluid. The present symptoms were considered to be caused by the pressure difference due to rapid change in atmospheric pressure from low (the highland) to normal (the level ground).

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We reported a case of aortitis syndrome in a 65-year-old female patient who had been suffering from chronic intense pain of occipital region, nape and left shoulder, and ataxia for about two years. The symptom was not controlled by the administration of NSAIDs, anticoagulant drug, platelete aggregation inhibitor, cerebral metabolic enhancer and so on. Stenosis of left vertebral artery was revealed by neck MRA, and blood hypoperfusion of cerebellum and left occipital lobe was disclosed with brain perfusion scintigraphy. The symptom was successfully treated with i. v. injection of 40μg prostaglandin E₁ and oral administration of 10mg/day prednisolone. We suspected hat blood flow effect of prostaglandin E₁ and anti inflammatory effect of steroid treatments were effective in a patient with aortitis syndrome.

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A 75-year-old male has suffered from chronic idiopathic hiccup for ten years. Conventional treatment, such as stellate ganglion block, phrenic nerve block, and medication with carbamazepin had no effect. Although baclofen treatment rather increased the frequency of hiccup, the duration of the attack of hiccup was decreased. As a result, the total hours of hiccup in a month and in a day was decreased by baclofen treatment. Furthermore, baclofen treatment improved the complicating symptoms, such as dyspnea and vomiting, brought on by hiccup.

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Two elderly patients with serious complication who suffered from idiopathic trigeminal neuralgia received pharmacotherapy and permanent trigeminal nerve block treatment. However, their improvement was only slight. Stereotactic gamma radiosurgery therapy, a type of the radiotherapy treatment, was attempted. In both cases, a 2-3mm periphery in which the trigeminal nerve entered the brain stem was the irradiation goal point, and 80 Gy were irradiated in a single shot. Excellent results were obtained in both cases, and there were no side effects such as dysesthesia or hypesthesia. This method may be an effective treatment in patients with intractable trigeminal neuralgia.

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A 54-year-old man complained of an attack of severe pain in the right side of the face. He had experienced similar attacks at 43 and 50 years old. The pain attack started as neuralgic pain in the first trigeminal division and was immediately followed by ipsilateral periocular headache, accompanied by autonomic signs, such as conjunctival injection, nasal stuffiness and drooping eyelid. The neuralgic pain was triggered by tactile stimulation of the eyebrow. Carbamazepine and stellate ganglion block diminished the intensity and frequency of attacks. Supraorbital nerve block was effective in stopping the attack immediately.

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We report a case of Complex Regional Pain Syndrome (CRPS) complicated with liver dysfunction during continuous epidural mepivacaine treatment. A forty-five-year old woman was admitted to our hospital with pain of the right hand. After a diagnosis of CRPS, she received continuous epidural block with 1% mepivacaine and intravenous regional sympathetic block using 10mg guanethidine. Gradually, her pain almost disappeared 3 weeks after these treatments. However, on the 25th hospital day, she complained of epigastric discomfort and general malaise. The serum GOT and GPT levels increased to 130 and 408IU/l respectively. The continuous epidural block and drug therapy were immediately discontinued. The rise in transaminases persisted for a month after general malaise disappeared. The increase of serum transaminases and eosinophilia was most suggestive of drug-induced liver dysfunction. Mepivacaine was suspected as the cause owing to the course of laboratory data. It is concluded that liver function tests are essential during continuous epidural block.

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Methylphenidate improved opioid-induced somnolence and neurobehavioral disorder in 4 terminal cancer patients. All the patients had suffered from cancer pain and morphine-induced drowsiness, which limited further use of morphine. Small doses of methylphenidate (1) counteracted the morphine-induced daytime drowsiness and night-time awakening, (2) brought good analgesia owing to further use of morphine and (3) treated neurobehavioral disorders in eating, conversation, and walking. No severe adverse effects requiring discontinuation of methylphenidate were observed in our experience. Methylphenidate is effective for opioid-induced daytime somnolence and improves the quality of life in terminal cancer patient.

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