There is little question that pain is a sensation with special structural, functional, and perceptual properties. The total pain experience is the result of 1) nociceptive signal transduction at the peripheral receptors, and/or 2) nociceptive signal conduction along the peripheral nerves, and/or 3) modulation of signal transmission at the spinal level, and/or 4) pain perception at the supraspinal sites, and/or 5) emotional reactions and associated sensations at the cortical level. In treating the specific case of pain syndrome, it is essential to understand the phase of pain, the type of pain, and location of the specific pain pathway involved. Each analgesic mode of therapy and each analgesic agent have their own mechanisms and sites of action. The optimum pain relief in each specific case of pain syndrome can be attained, first, by obtaining the correct diagnosis of pain syndrome including (a) the phase of pain, (b) the type of pain, and (c) the site of transmission of the pain signal as discussed above and, second, by administering the proper and rational pain treatment.

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The effect of nerve blocks to many pain syndromes is recognized but the proper use of nerve blocks requires solid knowledge and technical skill. Therefore, the various and many complications was caused by the nerve block therapy without satisfactory training. The investigations of that accidents or instructive experiences contribute to knowledge and training of young pain clinicians.
Not only techniqual trouble but failures of informed-consent was descrived in this report. Becouse, if the worst comes to the worst, failures of informed-consent is imperiled to suicide.
The writings was overlaped special lecture in the 3rd Pain Coference of Chugoku Sikoku and the report of Anesthesia & Resuscitation (30: 247-251, 1994).

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Treatment of chronic pain is one of the most important issues in the field of pain clinic. Although the mechanism of chronic pain is not well understood, the clinical and experimental evidences show that the nociceptive neuronal system is sensitized in chronic pain patients. The principles of drug therapy of chronic pain are to normalize the nociceptive system. Tricyclic antidepressants, anticonvalsants, systemic local anesthetics, opioid analgesics and NMDA receptor antagonists are now used clinically, which inhibit the excitatory neurons and/or excite the inhibitory neurons in nociceptive neuronal system. Although drug therapy is not so efficient as to relieve all kinds of chronic pain, the development of combination drug therapies and new drugs resulting from the progress of neuroscience will promise the future of the drug therapy.

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The CRPS cases treated in the Pain Clinic are more in number with serious phase. On the other hand, in our Orthopaedic Department in hospitals have more chances to treat early phases of the CRPS as we treat fresh trauma cases. Due to these, there are quite differences in reaction toward the CRPS.
I have retrospectively reviewed the CRPS cases that I had treated since 1987 and have analysed the combination of the symptoms and views with methods of treatment, then the results. In CRPS type 1, there were many cases with severe edema in the first medical examination. For these cases, treatment with steroid mainly were effective. The cases after decreasing edema at the first examination, steroid were ineffective in many cases, though various methods were used, there were a few which I could foresee the result. The only procedure that obtained a good retrieval was with the endoscopic thoracic sympathectomy in the case of temporarily well effective stellate ganglion block. In CRPS type 2, there were many cases with less edema and the results were disappointing though various treatment were given, including surgical treatments. It is our mission to start a treatment while edema is severe, when it goes far and edema decreases, then it will become more difficult to be cured.

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It is well known that respiratory depression ensues after major surgery due to post-operative pain. Although opioid can produce good analgesia, it sometime causes resoiratory depression postoperative patients. Epidural analgesia improve respiratory function by means of maintaining deep breathing and cough reflex. Those offects lead to prevent atelectasis and other lung complications. However, some patients require vasopressor due to significant sympathetic block when large doses of local anesthetics were used to obtain complete analgesia.
Clinical practice of epidural administration of opioids for analgesia was introduced in 1979. Although the epidural opioids excellent pain relief, the incidence and severity of side effects such as resoiratory depression associated with large doses limits its safty use. It is recommended the concurrent use of low dose of opioids and low concentration of local anesthetics since the combination of those agents, can produce the synergistic analgesia.
Recently, in the field of pain management, a lot of studies regarding opioids agonists and antagonists have been done. It is important to continue such investigation and elucidate analgesia system to develop safer pain control methods.

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Efficacy of Gasserian ganglion block for trigeminal herpetic pain was evaluated retrospectively. Gasserian ganglion blocks using local anesthetics and corticosteroid were performed under fluoroscopy for 19 patients associated with trigeminal herpetic pain or postherpetic neuralgia. Short term (2 weeks) efficacy rate was 47% and long term (2 years) efficacy rate was 58%. In patients with pathologic character deviation, short term effects of the block were poor, and in cases with sensory deficit, long term effects were poor (p<0.01, respectively).

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Diurnal variations of human pain sensitivity have been reported and diurnal variations of pain threshold have been demonstrated in laboratory animals. The biological rhythms can be divided broadly into two categories: exogenous rhythm caused by transition of external environment and autonomic endogenous rhythm. This study investigated in which of these two categories the diurnal variation of pain threshold fell. Experiments were conducted on male ddY mice (5 weeks old) in three photoperiods: 12 hour-light and 12 hour-dark cycle (lights on 0630 and lights off 1830), constant dark and constant light. The pain thresholds were measured by hot plate test (55.0±0.2°C) at 0800-0900, 1200-1300, 1600-1700, 2000-2100, 0000-0100 and 0400-0500. The pain thresholds of 1600-1700 and 2000-2100 were significantly higher than those of 1200-1300. The diurnal variation was not observed in either constant dark or constant light. There was a significant difference among transitions of pain thresold under the three photoperiod conditions. The thresholds in constant dark stayed in the vicinity of average level in dark-light cycle, while the thresholds in constant light approximated the minimum level in dark-light cycle. The results suggest that the diurnal variation of pain threshold might be caused by exogenous rhythm.

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Objective: To study retrospectively the sensory disturbances and the thermograms of patients who suffer from herpes zoster-associated pain and to estimate the severity and prognosis before nerve block treatment.
Methods: The sensory disturbances (either hypesthesia or hyperesthesia) of zoster-affected segment(s) and average temperatures of the affected skin were compared with those of the contralateral normal skin in 78 patients(male:female=42:86, age 66±12) with zoster-associated pain during their first visit to our clinic. In 35 of 78 patients, the follow-up data for individual patients were obtained. The relationships between sensory disturbances, skin temperatures and treatment periods were evaluated.
Results: The temperatures of affected skin in patients who came to us within 30 days from the onset were significantly (p<0.05) higher than those in whom symptoms had persisted for more than 31 days. The skin temperatures of most patients with trigeminal nerve involvement were less elevated, and the temperature courses were different from patients with thoracic nerve involvement. Before our treatment, the subjective symptoms of patients who revealed tactile hypesthesia were significantly (p<0.05) longer than those who did not. The differences of temperature between affected and normal segments were decreased after treatment. In most cases, there was an improvement in sensory (tactile and cold) disturbances.
Conclusion: There were several new findings as to the changes of sensory disturbances and skin temperatures of patients who suffered from zoster-associated pain. In order to estimate the prognosis of zoster-associated pain before treatment, sensory disturbance (especially tactile hypesthesia) may be more useful than thermographic findings.

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Plasma concentrations of morphine (MOR), morphine-3-glucuronare (M3G) and morphine-6-glucuronare (M6G) were analyzed in 3 renal dysfunction patients who had received morphine. The patients showed increased plasma concentrations of MOR, and marked increases in M3G and M6G. These results indicare that MOR metabolites accumulate in plasma more easily than MOR itself in advanced cancer-related pain patients with renal dysfunction. In cancer patients with renal dysfunction, assessment of plasma concentrations of MOR and MOR metabolites is necessary determine the optimal MOR doses.

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Two patients with abducense nerve palsy secondary to herpes zoster infection on their facial region were cured by Stellate ganglion block (SGB). An 81-year-old woman suffering from facial pain, facial eruption and diplopia was admitted with the diagnosis of right trigeminal herpes zoster and right abducense nerve palsy. After the skin lesion resolved, the abducense nerve palsy and the facial pain remained. SGB using 1% mepivacaine was initiated once a day. The patient's right facial pain completely disappeared and her abducense nerve palsy also recovered with 15 attempts of right SGB. A 72-year-old woman who complained of left facial nerve palsy, left postauricular pain, eruption, and diplopia was diagnosed with Ramsay Hunt syndrome associated with left abducense nerve palsy. Although the facial nerve palsy was cured mostly by drug therapy, the abducense nerve palsy remained, left SGB using 1% mepivacaine was started once a day. Her abducense nerve palsy was improved by 13 attempts of left SGB. The therapeutic course of these two patients suggests that SGB is effective not only for pain due to herpes zoster but also for complications, and SGB performed at an early stage of the disease shortens the duration of the illness.

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Neurotoxic symptoms due to accumulation of opioid metabolites were observed in a patient with renal imparement. The patient was a 69-year-old man who had intractable cancer pain, due to Pancoast tumor, which had been palliated by systemic opioids. The plasma concentrations of morphine, morphine-6-glucronide and morphine-3-glucronide were measured by high performance liquid chromatography (HPLC). When morphine metabolites had accomulated, the patient showed excitatory symptoms of the central nervous system (CNS), such as cognitive failure and myoclonus. The administration of morphine was decreased and changed to fentanyl.
After the change, the patient had adequate analgesia without adverse CNS symptoms.
In palliative care with opioids, for patients with chronic renal impairment, we conclude that it is useful to monitor plasma concentrations of morphine and its metabolites in order to achieve good quality pain control.

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