According to a recently released definition by the International Association for the Study of Pain, radiculopathy is classified as neuropathic pain (NeP). However, it may have different underlying pathophysiological mechanisms compared to other conventional NeP (cNeP) diseases, this is because non-steroidal anti-inflammatory drugs seem to be more effective for radiculopathy than for cNeP. Here we examined the differences between radiculopathy and cNeP by comparing pain characteristics that were described in the McGill pain questionnaire (MPQ). A total of 100 patients with radiculopathy and 362 with cNeP completed the MPQ, and its 20 elements of were then analyzed. Eleven elements were commonly extracted by the factor analysis from the two groups. Next, we found a discriminant function, which seemed to efficiently discriminate cNeP from radiculopathy. However, the canonical rate and discriminant rate were very low (0.31% and, 41%, respectively), and consequently the function failed to discriminate them significantly (p=0.99). The pain characteristics of cNeP and radiculopathy profoundly resembled each other, suggesting that their underlying mechanisms may also be common.

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FiRST (Fibromyalgia Rapid Screening Tool) is a brief questionnaire comprised of six "yes/no" questions for the detection of fibromyalgia syndrome. For clinical use, however, it requires further validation among various chronic pain syndromes. After authorized translation into Japanese and acquiring FiRST authorization for academic use, we used the Japanese FiRST in our chronic pain outpatients as questionnaires. The FiRST questionnaire was used to assess 71 patients with chronic pain resulting from fibromyalgia (n=11), and the results were compared with other chronic pain patients (n= 60). A cut-off score of 5 (the number of positive items) revealed the identification of fibromyalgia patients with a sensitivity of 100% and a specificity of 74.4%. Each of the six questions revealed a significant difference (Fisher test) in comparisons between fibromyalgia and the other chronic pain syndromes group. In conclusion, FiRST is a simple questionnaire with excellent discriminative value in daily practice, comprehensively delineating fibromyalgia.

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We conducted a retrospective study to evaluate the postoperative analgesic efficacy and side effects of two common analgesic techniques in patients undergoing video-assisted thoracic surgery (VATS) for lung cancer. A total of 98 adult patients under categories 1-3 of the American Society of Anesthesiologists` physical status classification system were divided into two groups-a patient-controlled epidural analgesia (PCEA) group, which included 82 patients who had received a mixture of 2 μg/ml fentanyl and 1.5 mg/ml ropivacaine, and the intravenous patient-controlled analgesia (IVPCA) group, which included 16 patients who had received 1 mg/ml morphine. Pain intensity in both groups, measured by a 100-mm non-graduated visual analog scale (VAS), was < 30 mm at rest in most cases in both groups. However, the VAS score during movement was 48.5 mm in group PCEA and 60.3 mm in group IVPCA on the day of surgery. Nausea and vomiting were observed in 18% of patients in group PCEA and 25% in group IVPCA. The IVPCA patients were significantly more sedated than the PCEA patients. We conclude that patients undergoing VATS may not have been provided sufficient analgesia during movement in postoperative pain management.

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RI cisternography (RIC) and CT myelography (CTM) are used to detect cerebrospinal fluid (CSF) leakage in patients with intracranial hypotension. Although several reports claimed that RIC had a risk of false positives and false negatives, no study has been made to directly compare CTM and RIC. In our research we selected 18 cases (8 men and 10 women) of spontaneous intracranial hypotension who met the diagnostic criteria of the international classification of headache disorders, 2nd edition, and compared the findings of RIC and CTM. Results: In RIC, indirect signs (delayed ascent of the RI or early bladder RI accumulation) were observed in all cases, but a direct sign (paravertebral RI accumulation) were observed in 12 cases (67%). In CTM, all cases (100%) showed an epidural collection of contrast media. An epidural collection of intrathecally administered contrast media is proof that active CSF fistula is present in patients with spontaneous intracranial hypotension. CTM is more accurate and sensitive than RIC in detecting CSF leakage in patients with spontaneous intracranial hypotension.

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We retrospectively studied doses of tricyclic antidepressants (TCAs) for the treatment of non acute zoster-associated pain (more than 30 days after the onset of herpes zoster [ZAP]) in 58 patients who visited our department. TCAs had been taken in 26% of the patients, and anticonvulsants in 5%. We prescribed TCA, either amitriptyline or nortriptyline, to 88% of the patients, and anticonvulsants, either gabapentin or valproic acid, to 58%. Initial median daily dose of amitriptyline was 10.0 mg, which after 4 weeks was gradually increased to 50.0 mg (quartile range 22.5-93.8 mg). Mean pain decreased from 66.5 mm to 23.2 mm on a 100-mm visual analog scale (VAS). The initial median daily dose of nortriptyline was 10.0 mg, which after 4 weeks was gradually increased to 30.0 mg (21.5-50.0 mg). Pain decreased from 60.6 mm to 27.9 mm on VAS after 4 weeks. TCAs reduced non acute ZAP. The doses of TCA to control non-acute ZAP varied from patient to patient greatly.

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Some physicians in Japan have insisted that whiplash-associated disorders (WADs) are caused by traumatic cerebrospinal fluid (CSF) leak. Several studies have reported that CSF leak was detected on radioisotope cisternography (RIC) in the lumbosacral region of WAD patients. However, RIC may create false positives by detecting nerve roots or cysts as a CSF leak, whereas the appearance of contrast medium in the epidural space on computerized tomography myelography (CTM) demonstrates a CSF leak directly. We compared the findings of RIC and CTM in 41 patients with WAD. As a result, paraspinal RI accumulation (PSA) was observed in 20 patients, and was located in the lumbosacral region in 19 patients on RIC. In contrast, no epidural collection was observed on CTM, whose findings revealed that root sleeves and cystic structures were observed at the locations in which PSA was noted on RIC. The results indicated that traumatic CSF leak was not observed on the CTM in WAD patients, in which a CSF leak was suspected on the RIC.

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Current information regarding the usage and effects of pregabalin in Japanese post-herpetic neuralgia (PHN) patients is inadequate because the drug was only recently approved for use in Japan. We are now prescribing pregabalin based on a simple prescription protocol we made. In this study, we surveyed retrospectively the changes in pain scores and the occurrences of side effects resulting from pregabalin prescribed on the basis of our protocol. We studied patients who started to take pregabalin for PHN from August to November 2010. In 11 of those surveyed, the numerical scores of continuous pain before and after prescription were 3 [0-8] and 3[0-7], respectively, and the difference was not statistically significant. But pregabalin attenuated the pain scores significantly from 4[0-9] to 2[0-7] in paroxysmal pain. Our study suggests that pregabalin has analgesic effects on Japanese PHN patients, especially those in paroxysmal pain.

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Some patients suffer from severe remaining or recurrent pain after implantation of a spinal cord stimulation (SCS) system. Therefore a trial of SCS with additional leads for such pain was performed on three patients with chronic regional pain syndrome, one in a leg, one in failed back surgery syndrome, and one in lumbar spinal canal stenosis. Intravenous antibiotics were given before and after the trial in all cases. The trial duration was approximately 24 hours to avoid infection. The pain in every case was decreased to less than 50 % of the pre-trial pain, and new leads were implanted a few months after the trial, also resulting in good pain relief. Despite the short duration of the trial, the patients could evaluate the effect of its stimulation because their experience with it had been sufficient. A trial of SCS with additional leads for patients with remaining or recurrent pain after permanent implantation of an SCS system is thus a valuable procedure to improve the quality of pain relief.

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We report a case of catheter infection caused by skin disorders and delayed cerebrospinal fluid leakage in the intrathecal analgesia. The patient was a 57-year-old male, and intrathecal analgesia was performed for left leg pain caused by rectal cancer. A catheter was placed in the intrathecal space after dural puncture with an epidural needle, which was substituted for the epidural space catheter port. Although the analgesia was effective, skin disorders were caused by cerebrospinal fluid leakage after 8 weeks of placement. A catheter port was removed because of the percutaneous catheter infection after 9 weeks of placement. Even though no established treatment for cerebrospinal fluid leakage is abailable, additional active measures should have been taken during hospitalization to prevent the infection in this case. Also, the development of a special device is necessary to minimize the risk of cerebrospinal fluid leakage and to decrease the risk of infection.

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We report a patient with neck and shoulder pain diagnosed as carcinomatous meningitis caused by metastasis of breast cancer. A 54-year-old woman developed this pain 8 months after mastectomy. She was revealed by magnetic resonance imaging and computed tomography to have no malignancy, so we first started pain treatment. Occipital nerve block and triggerpoint injection improved her pain, but 3 weeks later, the treatments became less effective, and the pain increased in sensitivity; thus we consulted neurosurgeons. They found meningeal signs diagnosed as carcinomatous meningitis by cerebrospinal fluid examination. In a case of progressive and persistent pain, we should suspect the presence of malignancy and expect to find evidence of meningeal signs.

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Although pregabalin is a first-line drug for neuropathic pain, including postherpetic neuralgia (PHN), it may cause some side effects, such as dizziness, somnolence, dose-dependent peripheral edema, and weight gain, which may influence patients to abandon its use. When pregabalin is used for PHN, the starting dose is usually 150 mg taken twice a day. We report four cases that at another hospital had discontinued pregabalin at 150 mg/day because of adverse effects. It was re-started in our department at 75 mg/day, which was gradually increased to 150 mg/day. All patients were able to continue pregabalin without adverse effects, which led to substantial improvement in the symptoms of two patients. For elderly patients, it may be appropriate to start at a low dose, wait until the side effects go away, and then gradually increase the dose until the benefits take effect.

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We experienced a surgical case with a large amount of hemorrhaging from an epidural puncture aperture immediately after surgery. The clotting studies, which were screened five days prior to surgery, were within normal limits. In the postoperative clotting studies, prothrombin time (PT) and hepaplastin test (HPT) demonstrated an unexpected coagulopathy, but activated partial thromplastin time (APTT) was still normal. These findings suggest that F VII, which is a vitamin K-dependent coagulation factor, should be decreased. So we suspected that this coagulopathy was caused by vitamin K deficiency. Preoperative oral limitation, insufficient absorption caused by ileus and treatment with cephem antibiotics had led to this deficiency. Vitamin K and fresh frozen plasma were intravenously administered just after these findings, and bleeding tendency was then improved; this patient now has no neurological impairment. We should pay attention when we administer cephem antibiotics containing N-methyl-thiotetrazole to a patient with long time fasting.

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We report a patient whose severe phantom limb pain was alleviated by continuous epidural block and sciatic nerve block. A 73-year-old woman developed phantom limb pain and stump pain after below-knee amputation for arterioscleotic obliterans. After receiving continuous epidural block for 2 weeks, her phantom limb pain and stump pain gradually decreased. Pulsed radiofrequency under ultrasound guidance was later performed to the sciatic nerve, and the pain was well controlled.

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A 65-year-old man who underwent liver transplantation three years ago had severe renal failure caused by nephrosclerosis. He was managed with immunosuppressive therapy against rejection. He suffered from acute herpetic pain in his left chest and back for 13 days and received medical treatment. We started pregabalin at 25 mg/day. Although the pain was improved, we stopped pregabalin 8 days later because of adverse effects, i.e., dizziness and balance disorder. Hemodialysis was introduced for aggravation of the renal function 10 days later. Even though the adverse effects were gone after the hemodialysis, the pain recurred. Therefore we resumed pregabalin at 12.5 mg/day. The pain was improved, and the adverse effects were mimimal. Hepatic encephalopathy gradually worsened, so we stopped again pregabalin. Because pregabalin is eliminated by kidney, it should be strictly titrated in patients with renal failure. Differential diagnosis would be needed for hepatic encephalopathy and the adverse effects of pregabalin in severe hepatic failure.

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We report an elderly woman who developed acute severe abdominal pain and bilateral lower extremity paralysis 5 h after an epidural block. Her abdominal symptoms disappeared and her lower-limb strength returned 10 h after the block. Diagnosis was difficult on the day of onset because an MRI revealed no significant compression of the spinal cord, but a subarachnoid hemorrhage was suspected in an arachnoid cyst at the S2 level. Two days after the epidural block, she complained of weakness of the bilateral foot dorsiflex, and an MRI revealed epidural hematoma and spinal cord ischemia at the T11-L1 level. Computed tomography of the brain revealed nominal subarachnoid hemorrhage. We hypothesized that an epidural block would have triggered this kind of insidious hemorrhage and hemorrhagic venous ischemia of the spinal cord.
These neurological damages may be irreversible; therefore clinicians should be aware of these rare complications and the need to perform careful neuroradiological evaluation after an epidural block.

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We have performed intrathecal injections of betamethasone for uncontrollable cancer pain since 1999. We report on a patient who received repeated such injections because of severs cancer pain. A 70 -year-old man with a 12th thoracic vertebral tumor had intractable lower limb pain with gait-disturbance, despite conventional cancer pain treatments. After informed consent from the patient and his wife, betamethasone (2-3 mg) combined with saline was injected into the lumber intrathecal space through a 27 G pencil-point needle once a week. As a result, he had long-lasting pain relief and improvement of ADL (activity of daily living) with no adverse effects, such as neurotoxicity caused by glucocorticoid. Pain relief and improvement of his ADL were maintained for 19 months. But, his pain eventually recurred, and his ADL was again disturbed. MRI revealed a tumor-sized development in the T12 vertebra. Despite intrathecal betamethasone injections, his severe pain was not relieved. The intrathecal injection of betamethasone has the possibility of usefulness in treatment of intractable cancer pain, especially in vertebral tumors.

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It is common in Japan for implantable pulse generators (IPG) to be inserted in the abdominal region. Inserting one in the buttock region is superior to inserting it in other regions in terms of the degree of invasiveness, patient quality of life (QOL) and aesthetic considerations. We report a case in which Eon Mini, the world's smallest IPG, was inserted in to the buttock region to carry out pain control within spinal cord stimulation (SCS). The subject was a 41-year-old female who had undergone surgery for lumber disk herniation 10-years earlier. Although pain control was performed with nerve block and drug therapy because of the symptoms restarting, the analgesic efficacy was poor; therefore the subject underwent SCS. The patient had a desire to have a baby, and an IPG was inserted into the buttock region, avoiding insertion into the abdomen. Now, after 10 months postsurgery, a high analgesic efficacy is observed based the pain control having been well carried out.

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