We retrospectively analyzed the efficacy and side effects of gabapentin for the treatment of intractable neuropathic pain in 28 patients (postherpetic neuralgia [n=8], complex regional pain syndrome type I [n=6] and type II [n=2], brachial plexus injury [n=2], spinal cord injury [n=2], and others [n=8]). Gabapentin was begun at a mean of 42 months after the first visit to our department with initial doses of 200-600mg/day. The dose was titrated in each patient. The pain in 14 patients (50 %) significantly decreased after treatment with gabapentin with doses of 200-2400mg/day. The most frequent side-effects were somnolence (29 %) and nausea (21 %); 8 patients withdrew gabapentin because of side-effects. However, there were no major severe side effects in our patients. We conclude that gabapentin is efficacious for the treatment of neuropathic pain syndoromes in some selected patients.

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PainVision^TM PS-2100 (Osachi Japan), is an instrument that shows pain degree calculated from current perception threshold defined by the lowest electrical current detected by patients and pain compatible electrical current defined by the electrical current judged as being compatible with the intensity of ongoing pain by patients. The results of pain treatment were evaluated by PainVision and visual analog scale of pain (VAS) in 25 patients. Pain intensities decreased in 16 patients (relief group), and did not change in 9 (no-relief group). In the pain relief group, pain intensities measured by VAS, pain compatible currents, and pain degrees decreased significantly and current perception thresholds increased significantly, after treatments. By contrast, in the no-relief group, pain intensities measured by VAS, pain compatible currents, and, pain degrees did not significantly change after treatments; however, current perception thresholds decreased after treatments. Pain degree showed the highest positive correlation with pain intensity by VAS. We conclude that PainVision may be useful because it can express results of pain treatment by objective pain degree rather than subjective pain intensities by VAS.

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We report a patient who received high-dose transdermal fentanyl to relieve cancer pain. A 56-year-old man with rectal cancer was referred to our pain center because of uncontrolled cancer pain. He had received slow-release morphine 150 mg/day and transdermal fentanyl at a rate of 25 μg/hr. Since the patient had severe constipation and the pain was not controlled, morphine was discontinued and the dose of transdermal fentanyl increased. Addition of intravenous lidocaine and amitriptyline was not effective to control the pain. Intrathecal phenol and lumbar epidural blocks transiently relieved the pain. As the pain worsened with the growth of the tumor, transdermal fentanyl was increased at a rate ≤ 650 μg/hr. The pain was controlled to around 4 of 10 on a numerical score of pain. He was alert and no apparent respiratory depression was noted until his death, which occurred 7 months after admission. Fentanyl concentration in the blood was 9.8, 21.6, and 22.0 ng/ml when the patient received transdermal dosing at 200, 500, and 650 μg/hr, respectively.

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We report three patients who developed de novo pain in the previously painful lower limbs. One patients had post-stroke central pain, and two had postherpetic neuralgia. Pain on movement, neurological examination, and magnetic resonance imaging of the lumbar spine suggested that the pain was caused by lumbar disc herniation. The three patients had a positive straight leg raising test on the painful side after development of the new pain. When aggravation of pain occurs in previously lower painful limbs, lumbar disc herniation should be borne in mind.

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We report a patient with long-standing failed back surgery syndrome who was successfully treated with collateral meridian therapy. A 39-year-old man had had three back surgeries for pain caused by herniated lumbar disc; however, lumbago and bilateral sciatica gradually increased and his ambulation became difficult because of severe pain. Caudal block was ineffective. Oral opioid, antidepressant, anticonvulsant, and antiarrhythmic drugs, prostaglandin E1, or ketamine was not effective. Sciatic nerve block with a local anesthetic and electrical therapy with invariable direct currents produced slight and transient pain reduction only for 2-3 days. However, collateral meridian therapy performed even 6 years 2 months after the onset promptly relieved the pain (0 cm on visual analog scale [VAS] of pain) at rest. The pain was negligible even during walking (0.5 cm on VAS). Collateral meridian therapy needed only 3-5 minutes to perform. It was repeated twice monthly, for a total of 9 times. The pain became stabilized at 0-2 cm on VAS without any analgesics. He could walk without a stick. We conclude that collateral meridian therapy can be effective in selected patients with failed back surgery syndrome even if it is long standing.

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The authors report two patients with abdominal pain due to carcinomatous peritonitis that did not decrease despite large doses of fentanyl but decreased after addition of low-dose morphine. Case 1 was a 15-year-old girl with abdominal pain due to ovarian cancer with peritoneal dissemination. The abdominal pain was controlled by intravenous fentanyl at a dosage of 300 μg/day for the first 3 months; thereafter, the abdominal pain worsened. Continuous intravenous fentanyl ≤ 2400 μg/day with 16 daily rescues of fentanyl 100 μg plus intravenous ketamine did not control the pain. Addition of morphine at a dosage of 50 mg/day to continuous intravenous fentanyl, however, relieved the abdominal pain. Case 2 was a 33-year-old woman with abdominal pain due to gastric cancer with peritoneal dissemination. The abdominal pain was not controlled by continuous intravenous fentanyl ≤ 9600 μg/day with 25 daily rescues of fentanyl 200 μg plus intravenous ketamine. Addition of morphine at a dosage of 150 mg/day to continuous intravenous fentanyl, however, relieved the abdominal pain. We conclude that tolerance to fentanyl may have occurred in these two patients.

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