Toshimitsu Kitajima. Kyoko Saito*, Shinsuke Hamaguchi*, Masa-hiro Omoto*, Mutsuo Mishio*, Yasuhisa Okuda, First Dept of Anesthesiology, Dokkyo Univ School of Medicine, Mibu, Tochigi 321-0293,Japan

Aim of Investigation: Complex Regional Pain Syndrome (CRPS) often occurs after a trauma, but CRPS type 1 following traffic accidents is rare. We report four patients who developed CRPS type 1 following car collisions.

Methods: Four patients, one male and three females, felt persistent pain in the neck, shoulder and upper extremity after car collisions. They were treated by orthopedists but their pain was not relieved. They experienced coldness, cyanosis, hyperalgesia, edema, sudo-motor disturbance, or allodynia in the unilateral upper extremity one week to two months after the accidents. They continued treating with medication and rehabilitation therapy, but their symptoms did not improve. They were referred to us 5 months to 2 years after the accidents.

Results: They were diagnosed as having CRPS type 1 in accordance with the diagnostic criteria. MR imaging revealed that three patients had cervical disc hemiation. One patient was normal on cervical X-ray and MR images. Consecutive stellate ganglion blocks (SGBs) with local anesthetics were performed to improve their symptoms.

Conclusions: Minor injury around the cervical region after a traffic accident may induce increased sympathetic tone, followed by CRPS type 1. SGBs gradually decrease the symptoms.

REFLEX SYMPATHETIC DYSTROPHY: CRITICAL STUDY AND EVALUATION OF 30 CASES OVER 15 YEARS

Heinz Konrad. Physician of the Pain Therapy and Palliative Care Service of the Central Hospital of the Santa Casa de Sao Paulo. Sandra M.C.M. Coeli, Chief of the Pain Therapy and Palliative Care Service of the Central Hospital of the Santa Casa de Sao Paulo Largo Como 330, Sao Paulo, 04922-130, BRAZIL

Aim of Investigation: 1) verify the efficacy of the therapy programs employed; 2) see if there is any correlation between the studied parameters and the obtained pain reduction; 3) critically evaluate the therapy applied.

Methods: We studied 30 randomly selected patients suffering from RSD, who have been treated and followed in our Service over a period of 15 years (Jan. 1982 to Jan. 1997). Results: We found that, regarding RSD, our Service has results similar to those of other pain services in the world who deal with this pathology. We could not detect any correlation between the several parameters studied and the result of pain reduction.

Conclusions: We conclude that regarding the exact knowledge of the physiopathology of RSD, and its resulting rational therapeutic approach, we are still almost totally in the dark.

CAN AN ABNORMALITY OF THE A.RADIALIS CAUSE A COMPLEX REGIONAL PAIN SYNDROME (CRPS)?

Christian Lampl. Andrea Buzath and Dieter Klingler, Dept of Neurology, Psychiatry and Pain Clinic, General Hospital Linz, Austria

A 52-year-old woman observed a generalized swelling on the dorsal side of the distal pan of her right hand combined with a reddish color of the skin in the distribution area of the distal part of the n.radialis. The pain was described as constant burning which exacerbated by movement and during the nights. The distal dorsal pan of the hand and plantar tips of the fingers I-III showed a subjective increase in skin temperature. The initial laboratory findings revealed neither bone pathology (e.g. fracture), nor Raynaud's disease or any other signs of inflammatory illness (e.g. phlebitis). The measurement of the skin blood flow showed a mild increase between the distal upper extremities. In the neurological examination no nerve lesions or motor disturbances of the right hand could be found. In the noncontact skin temperature a side-to-side asymmetry of 1.55°C and hyperhydrosis were observed. A three-phase bone scan revealed a positive characteristic pattern ofperianicular uptake. Additionally, no pathological findings were observed in the MRI of the neck. An angiography of the right hand showed a very strong pan of the r.dorsalis of the a.radialis. On the basis of our findings we diagnosed this clinical presentation as a Type 1 CRPS. However, the patient had no initiating trauma in any of the extremities or visceral peripheral lesions. The only pathology we could find was this abnormality of the a.radialis.

LAMOTRIGINE IN THE TREATMENT OF PAINFUL DIABETIC NEUROPAHTY: A RANDOMIZED, PLACEBO CONTROLLED TRIAL

Y. Luna', C. Brecker³, D. Daoud¹', A. Ishay', E. Eisenberg". "Pain Relief Unit, ''Endocrine Inst, Rambam Medical Center, The Tech-nion - Israel Inst of Technology, Haifa 31096, and 'Endocrine Inst, Central Emek Hospital, Afula (Israel).

Aim of Investigation: Substantial evidence indicates that both sodium and glutamate channels are involved in the pathogenesis of neuropathic pain. Lamotriginc (L) is a novel antiepileptic agent that blocks voltage-sensitive sodium channels and inhibits the release of glutamate. The present study was aimed to test the efficacy ofL in relieving painful diabetic neuropathy.

Methods: Sixty patients were enrolled in a randomized, placebo (P) controlled trial. Subsequent to a 1 week washout period from previous analgesics, L dose was titrated from 25 to 400 mg/day over 8 weeks. Identical looking P was administered in a similar regimen. Pain level was recorded by each patient twice daily with the use of a 0-10 numerical pain scale (NPS). Blood glucose and hemoglobin AiC levels, as well as the McGill Pain Questionnaire (MPQ), Beck Depression Inventory (BDI), Pain Disability Index (PDI), were completed at the beginning and at the end of the study.

Results: An interim analysis of 34 (18 - L, and 16 - P) who already completed the study was performed. The drop in spontaneous pain (NPS) was greater in the L group compared to the P group throughout the entire study period, and at statistically significant level at L doses of 100-400 mg/day. Maximal pain reduction with L was 46%, and only 22% with P (p“0.001). A trend of improvement in PDI score was noted in the L group (a drop of 3.6 points compared to 1.4 in the P group; p=0.07). No differences in effect between L and P were found in MPQ and BDI scores, glucose and hemoglobin AiC levels, and incidence of adverse events.

Conclusions: Study results show that lamotrigine is effective and safe in reducing painful diabetic neuropathy.

AN ATTEMPT OF ELECTROCONVULSIVE THERAPY AS A TREATMENT FOR COMPLEX REGIONAL PAIN SYNDROME

Takeshi Maeda*'. Hitoshi Mcra'', Nagafumi Doi"², Mitsuru Naka-mura'², Kunihiro Isse'², Shizuo Takeyama"', Tatsuo Sameshima''
(SPON: K. Nishitateno) DeptofAnesthesiology' and Psychiatry², Tokyo Metropolitan Ebara General Hospital, Japan

Background: Complex regional pain syndrome (CRPS), one of the major conditions causing chronic intractable pain, often leads to suppression of activities of daily living (ADL) and depression. Electroconvulsive therapy (ECT), which is well established to have therapeutic effects on depression, has been reported to reduce intolerable pain associated with depression. Based on the experience that ECT reduced pain and allodynia due to postherpetic neuralgia and central post-stroke pain, we applied ECT to the patients with CRPS.

Subjects and Method: Subjects were 7 patients with CRPS (3 cases with type 1 CRPS and 4 cases with type 2). Based on the written consent from the patients, a course of bilateral ECT (110V for 5 sec, 6 to 12 sessions with interval of 1 to 7 days) was performed. The effect of the therapy was evaluated by objective findings on the patients. Especially, the reduction of the area of pain and the improvement of ADL were regarded as important criteria. Results: Severe pain causing suppression of ADL as well as allodynia disappeared and the area of the pain was reduced in five patients. ADIL was remarkably improved in those cases. However, no apparent improvement was obtained in two patients, who had psychological problems other than the pain.

Conclusion: ECT can be a choice of treatment for patients with CRPS.

INTRAVENOUS PHENYTOIN INFUSION RELIEVES ACUTE NEUROPATH1C PAIN: A RANDOMISED, DOUBLE-BLIND, PLACEBO CONTROLLED STUDY

Gary J McCleane Pain Clinic, Craigavon Area Hospital, 68 Lurgan Road, Craigavon, BT63 5QQ

Aim of Investigation: Oral anticonvulsants have an established role in the management ofneuropathic pain but may not be practical in the acute attack. Phenytoin has a long tradition in neuropathic pain and is available in parenteral form. The aim of this study was to examine the analgesic effect of IV phenytoin in acute neuropathic pain.

Method: A randomised, double-blind placebo controlled, crossover study of 20 patients with acute neuropathic pain. Patients received either phenytoin 15mg Kg'" in 1000ml 0.9% saline or 1000ml 0.9% saline (placebo) over 2 hours, and the following week those who received phenytoin received placebo and visa versa.

Results: Placebo infusion reduced numbness and sensitivity during infusion. Phenytoin reduced burning (p<0.05), shooting and sensitivity (both p<0.001), numbness (p<0.05) and overall pain (p<0.005) during the infusion period. Shooting pain remained less for 4 days, sensitivity for 2 days and overall pain for 1 day after infusion. All patients were light-headed at the end of phenytoin infusion (none in the placebo group). Two patients who received phenytoin developed transient skin rash.

Discussion: Intravenous phenytoin reduced pain in 14 out of 20 patients treated. Eight found the balance between effect and side effect to be favourable. This indicates that parenteral phenytoin may be useful in acute neuropathic pain and its use be more logical than parenteral opiates or NSAIDs. This analgesic effect may be useful in acute neuropathic pain and where the oral route of drug administration is not available.

Conclusion: The intravenous administration of 15mg Kg"' phenytoin reduces neuropathic pain, with this effect outliving the duration of action of this drug.

PERIPHERAL NEUROPATHIC PAIN - A MULTIDIMENSIONAL BURDEN TO PATIENTS.

Kann Meyer*'. Ann Kvamstrom'², Lars-OlofNordfors³, Erik Kinnman', Torsten Gordh², Ann Kristofferson', 'Astra Pain Control AB, S-151 85 Sodertalje, Dept of Anaesthesiology and Intensive Care, Univ Hospital, Akademiska Sjukhuset, S-751 05 Uppsala, 'Dept ofAnaesthesiology and Intensive Care, Danderyd Hospital, S-182 88 Stockholm, Sweden.

Aim of Investigation: To investigate the interference of chronic peripheral neuropathic pain (PNP) on quality of life (QoL).

Method: A cross sectional observational study in 126 PNP patients treated at pain clinics in Sweden. Efficacy of current treatment and reasons for discontinuation of previous treatments were recorded. The intensity of pain at rest as well as movement, touch and cold evoked pain was assessed using a visual analogue scale (VAS, 0-100). A 7-graded verbal scale was used to study 25 pain and side effect related symptoms. Health related QoL was evaluated using SF-36, Nottingham Health Profile and a Health Rating Scale (VAS, 0-100).

Result: Only 40% of previous treatments provided pain relief. For these patients, the reason for discontinuation was insufficient effect in 41%, severe side effects in 39% or both in 19%. A majority of patients had tried several treatments. The efficacy of current treatment was also poor. The median VAS score for pain at rest was 40, movement 53, touch 34 and cold 41. The type of pain that was most intense varied between patients. Difficulty to sleep, lack of energy, drowsiness, difficulty to concentrate and dry mouth were the most bothersome symptoms. All dimensions of SF-36 and NHP were significantly impaired. Employment status was reduced due to pain in 52% of the patients.

Conclusions: Limited clinical efficacy and tolerability ofneuropathic pain treatment causes a substantial impairment of QoL. In evaluation of treatment efficacy, the impact on QoL should be assessed in addition to pain intensity measures.

EFFICACY OF INTRAVENOUS LIDOCAINE IN NEUROPATHIC PA1N-THE EFFECT OF PATIENT AND PAIN CHARACTERISTICS

T. Nagaro. S. Abe*, S. Kimura and T. Arai, Dept. ofAnesthesiol-ogy and Resuscitology, Ehime Univ., Ehime, 791-0295, Japan

Aim of Investigation: We investigated to find which neuropathic pains and patients respond well to intravenous lidocaine.

Methods: After obtaining informed consent, 115 patients with neuropathic pain were enrolled in this study. The pain severity (PS, range 0-10) was measured 1 min., 5 min., 15 min. and 35 min. after 1.5 mg/kg of lidocaine was administered intravenously over 1 min. The percentage of pain relief was calculated from the lowest PS. "Good" was defined when pain reduction was over 50 % and "poor" when it was below 50%. We investigated differences in pain relief accounting for differences in age and sex, site of the nerve disease, and pain characteristics (severity, duration and nature).

Results: Eighty-one of 115 (70.4%) patients experienced "good" pain relief. For peripheral nerve disease, 70 of 90 (77.8%) patients experienced "good" pain relief, which was higher than that from central nerve diseases (44.0%). Forty-seven of 58 (81.0%) patients with pains ofPS below 5 experienced "good" pain relief, compared to 58.2% who had pains ofPS above 5. Seventy-three of 95 (76.8 %) patients over 50 years old experienced "good" pain relief, compared to only 40 % of those below 50 years old. There were no differences for other characteristics.

Conclusions: This study suggests that the patients with the peripheral nerve diseases and mild or moderate pain and older patients benefit the most from IV lidocaine.

PHARMACOLOGICAL DIFFERENTIAL DIAGNOSIS OF THE MECHANISMS OF NEUROPATHIC PAIN SYNDROME.

Setsuro Ogawa. Jitsu Kato, Shigeru Saeki, Takashi Nakamura, Takahiro Suzuki, Miho Kashiwazaki, Surugadai Nihon Univ Hospital Dept. ofAnesthesiology, Tokyo, Japan

Aim of Investigation: To investigate the mechanisms ofneuro-pathic pain syndromes by pharmacological test, drug challenge test (DCT), in application of treatments.

Methods: Physiological saline (as a placebo) was followed by a test drug (phentolamine, thiamylal, lidocaine, morphine or ketamine) after 5 minutes from administration of physiological saline and VAS was observed every 1 and 5 minutes. IfVAS did not become zero, supplemental administration was performed in every 5 minutes up to 2 times (maximum 3 times).

Results: The results were summarized as follows; 1) Phentolamine positive in 32 out of 92 patients. 2) Thiamylal positive in 39 of 86 patients. 3) Lidocaine positive in 28 of 65. 4) morphine positive in 26 of 32. 5) Ketamine positive in 40 of 65. Relationship between the results of test and the efficacy of treatment used according to the results of DCT showed that there were a vourious responses to the subsequent treatments.

Conclusion: Mechanisms ofneuropathic pain should be considered when adequate treatments are intended to apply because the mechanisms are thought to be different in each patient with neuro-pathic pain. DCT is one of the useful procedures for assessment of the mechanisms of pain.

PREVALENCE AND CHARACTERISTICS OF POST CORONARY-ARTERY-BYPASS-GRAFTING (CABG) PAIN SYNDROME

Y. Pultorak³*, Y. Bar-El¹¹*, D. Pud, E. Eisenberg". 'Pain Relief Unit, ^ept of Cardiac Surgery, Rambam Medical Center, The Technion - Israel Inst of Technology, Haifa 31096, Israel.

Aim of Investigation: CABG is one of the most common surgical procedures performed worldwide. However, its frequent complication, the post CABG pain syndrome (PCPS), remains poorly documented. The present study was aimed to investigate the prevalence and characteristics of this syndrome.

Methods: Questionnaires regarding the presence and characteristics of chest wall pain were mailed to 504 of 540 patients who underwent CABG surgery at our institution during the years 1995-6. The results of the 386 responders were analyzed. 78 of them completed the McGill Pain Questionnaire (MPQ), and the Pain Disability Index (PDI), and were available for medical examination.

Results: 219 of the 386 responders (57%) reported chest wall pain which was different from the pre-operative ischemic pain, and were therefore categorized as PCPS. (Another 10% reported ongoing ischemic pain in spite of surgery). Moderate to severe pain intensity was reported by 142 subjects with PCPS (66%), regular analgesic consumption by 65 (30%), and significant interference with daily activities by 57 (28%). Mean MPQ score of the 78 examined subjects was 9.6±0.9. Subjects were able to walk 39±3 min, and to climb 33±4 stairs, indicating a non-ischemic nature of pain. In contrast, mechanical (pinprick) and thermal (Quantitative Thermal Testing) hypoesthesia was demonstrated over the left anterior chest wall demonstrating evidence for nerve injury. None of the above findings was found in patients who underwent thoracot-omy for valve replacement, nor in age matched healthy individuals.

Conclusions: PCPS is distinctive pain syndrome with a 57% prevalence. It may cause significant interference with daily activities, and is likely to result from injury to intercostal nerves.

HYPOTHESIS FOR SYMPATHETICALLY MAINTAINED PAIN: WHY DOES PHENTOLAMINE BLOCK PAIN EVEN WHEN SYMPATHECTOMY DOES NOT?

Angelo G. Rocco' and Stephen A. Raymond'* Harvard Vanguard Med. Assoc. ' Anes. Bngham & Women's Hosp. Harvard Med. School Boston MA 02115, USA

Aim of Investigation: Formulation of a hypothesis to explain observations drawn from our cases.

Methods: Retrospective study of our patients.

Results: 1) Pain and Dystonia have been relieved by systemic but not regional IV phentolamine. 2) Surgical sympathectomy has been effective, but often only for days. Whereas radiofrequency thermo-coagulation (RFTC) in the area of specific rami commnicantes has often been effective for months or years. 3) Pain and dystonia recur or persist even after a "complete" sympathectomy. 4) Once dystonia and/or pain are triggered by stimulating a certain area in the periphery, they cannot be stopped by anesthetizing that area. 5) Pain and dystonia can be rekindled by "nor-adrenergic events" such as surgery under general anesthesia or episodes of intense emotion. 6) During active RFTC dystonia can be produced, which then disappears as heating continues to complete the lesion. 7) Shortly after successful reduction of dystonia by RFTC applied in one region, dystonia can occur in response to peripheral or neural stimulation in areas not related to the treatment region. Such dystonia has subsided without treatment, or can be controlled by systemic phentolamine.

Conclusions: These observations lead us to suggest a specific anatomical substrate: neurons or "chromafftin" cells with cell bodies near the DRG that receive excitation from preganglionic sympathetic cells of the intermediolateral column. In response to central sympathetic drive, these cells express norepinephrine that excites DRG somata leading to locally driven sensory (pain) and motor (dystonia) abnormalities that can be suppressed by phentolamine when delivered so that it can access the DRG. We have been impressed by findings that susceptibility to chronic pain (and dystonia?) can be experimentally altered by breeding. It may be that either expression ofadrenergic receptors on DRG or the presence of our hypothetical chromaffm cells is the somatic phenotype that underlies this genetic susceptibility.

CHRONIC 1NTRASPINAL OPIOIDS INFUSION FOR TREATMENT OF MYELOPATHIC PAINS

L.A Rogano, M.J. Teixeira, H.C.E. Barrero, T.Y. Yeng LT, M. Okada, Pain Clinic, Univ ofSao Paulo Medical School, Rua Con-selheiro Brotero 1539 cj 12, Cep 01232-010, Sao Paulo - Brazil

Aim of Investigation: Prospective evaluation of the result of treatment of 13 patients presenting myelopathic pains with chronic spinal intrathecal infusion of morphine. Methods: 13 patients (9 male, 4 female), ages ranging from 22 to 60y, presenting chronic unbeatable myelopathic pains due spinal cord injuries at cervical (2), high thoracic (8) and low throracic (3) levels and resulting from gunshot injuries (5), close trauma (4), multiple sclerosis (1), post- laminectomy syndrome (1), parasitary myelopathy (1) and spinal tuberculosis (1) where initially treated with epidural infusion of3mg of morphine HCI during 2 weeks. 12 patients present significant improvement of the original pain and underwent implantation of Algomed (Meditronic) pumps for infusion of 1-6mg/day of morphine HCI into the spinal intrathecal compartment. VAS and Quality of life were evaluated.

Results: The mean initial VAS was 8.46 (5-101 and the 1.6(0-8). Minimun follow-up was 5m (5-30m). Nauseas/vomits occurred in 10 cases and were controlled with reduction in the dosage.

Conclusion: Chronic intrathecal morphine infusion is an efficient method for treatment of myelopathic pains.

PROGNOSIS OF PROLONGED ABNORMAL SENSATION AFTER NERVE AND TISSUE INJURY DURING DENTAL TREATMENT BY QUANTITATIVE SENSORY TESTINGS.

Eiii Sakamoto* Yoshiki Imamura, Masatsiigu Iwamoto*, Shunji Shiiba*, Hiroshi Kawahara, and Osamu Nakanishi, Dept ofAnes-thesiology, Kyushu Dental College, Kitakyushu, Japan

Aim of Investigation: Pain and abnormal skin sensation, such as allodynia and dysesthesia after nerve and tissue injury often persist for a long time. The aim of this study was to investigate ifQST is useful to prognose symptoms.

Method: 32 patients who had abnormal skin sensation after dental treatment or orofacial surgery enrolled in this study. Electric detection threshold (EDT) and touch perception threshold (TPT) using a Semmes-Weinstein aesthesiometer set were recorded to assess hypoesthesia. Magnitude of touch perception and/or evoked pain using a brush and a pin were numerically expressed by patient him/herself compared to the contralateral side. Data was collected again 12 months after the first examination, and was discussed what sensory test is useful for prognosis of prolonged abnormal sensation.

Results: Following findings were observed only within fresh cases. EDT and TPT significantly improved within 12 months after nerve and tissue injury, however, allodynia and dysesthesia often persisted. Initial EDT showed the lowest mean average in completely recovered cases, followed by fairly then poorly improved (p<0.01). Those who showed less than 2.0mA in initial EDT recovered satisfactorily except one case. Initial TPT showed a small mean average in completely recovered patients, too. A small value of initial TPT, however, did not necessarily lead to a satisfactory recovery. Magnitude of touch evoked sensation did not have significant roles in prognosis.

Conclusions: QST, especially EDT in fresh cases could predict prolonged abnormal sensation. Low thresholds in electric detection and touch perception close to the contralateral side seem to express less severe damage of the affected nerve, and satisfactory recovery in sensation.

ELECTROCONVULSIVE THERAPY REDUCES PAIN IN POSTHERPET1C NEURALGIA.

Tatsuo Sameshima*'. Nagafumi Doi'², Hitoshi Mera'', Mitsuru Nakamura'², Kunihiro Isse'¹, Takeshi Maeda'', Shizuo Takeyama"' (SPON: T. Hisamitsu), Dept. ofAnesthesiology' and Psychiatry², Tokyo Metropolitan Ebara General Hospital, 4-5-10, Higa-shi-Yukigaya, Ohta-ku, Tokyo, 145-0065, JAPAN

Background: Postherpetic neuralgia (PHN) often resists every treatments for many years, causing suppression in activities of daily living (ADL) and depression in some of those patients. Elec-troconvulsive therapy (ECT), which is well established to have therapeutic effect on depression, has been reported to reduce intolerable pain associated with depression. We applied ECT to the patients with PHN and observed a remarkable reliefer reduction of allodynia and pain.

Subjects and Method: Subjects were 6 male and 4 female patients with PHN. Two of those patients had pain arising from bone metastasis ofhepatocellular carcinoma or rheumatoid arthritis (RA) in addition to PHN. Based on the written consent from the patients and their families, a course of bilateral ECT (110V for 5 sec, 6 to 12 times with interval of one to seven days) was performed.

Results: Reduction of pain and allodynia was observed on the following day of the first trial of ECT in all patients. Although the pain and allodynia were surged back in the afternoon of the second ECT, they were markedly reduced on the following day. After a course of ECT, pain and allodynia were completely relieved in four patients and markedly reduced in six patients. On the other hand, hypoesthesia in the involved dermatozome remained unchanged and nociception in the healthy skin remained intact in all patients. Pain due to bone metastasis of cancer and RA remained unchanged. In 8 patients, pain and allodynia recurred after three months or more later. In 5 patients ECT was performed again, and the better and more long-standing effects were obtained.

Conclusion: ECT can be a choice of treatment for established PHN.

THE COMBINATION OF ORAL MORPHINE AND KETAMINE IMPROVES PAIN RELIEF IN POSTHERPETIC NEURALGIA COMPARED WITH MORPHINE OR KETAMINE ALONE.

Audun Stubhaug. Per Knstian Eide, Harald Breivik, Depts. ofAn-aesthesiology and Neurosurgery, The National Hospital, Univ of Oslo, Oslo, Norway.

Aim of Investigation: To evaluate both the effect of oral ketamine or morphine alone, and the combination of morphine and ketamine in the treatment ofpostherpetic neuralgia (PHN).

Methods: Fourteen patients with stable PHN were included (twelve completed) in this double blind, randomised complete crossover comparison. Each treatment was given for one week in four daily oral doses. After three days the dose of all active drugs was doubled. The four treatments were 1) ketamine 2 and 4 mg/kg/day, 2) morphine 0.25 and 0.5 mg/kg/day, 3) the combination of ketamine 2 mg/kg/day with morphine 0.25 mg/kg/day and ketamine 4 mg/kg/day with morphine 0.5 mg/kg/day, and 4) placebo (saline). Ongoing pain intensity was measured on a portable 0-100 mm visual analogue scale (VAS) data logger, and mechanical brush allodynia and windup-like pain (abnormal temporal summation of pain) was evaluated. Friedman's test (Conover) was used for statistical comparison.

Results: Baseline median pain was 67 mm (range 56-100). The combination of ketamine and morphine reduced spontaneous ongoing pain compared with both placebo (P = 0.002) and ketamine (P = 0.02), while morphine alone was superior to placebo (P = 0.05). Median VAS-reduction (interquartile range) compared with placebo was 15 mm (4 - 18) for ketamine + morphine, 10 mm (4 -15) for morphine, and 0 mm (-2 - 16) for ketamine. The combination also reduced windup-like pain significantly compared with placebo (P = 0.004) and morphine (P = 0.007), while ketamine alone was superior to placebo (P = 0.04). No effect on mechanical allodynia was found. Probably because side effects were frequent, the global satisfaction score improved only mmimally.

Conclusion: The results support findings in animal research that N-methyl-D aspartate (NMDA) receptor antagonists potentiate the effect of opioids on neuropathic pain.

VENLAFAXINE IN NEUROPATHIC PAIN.

Tiina Tasmuth. Eija Kalso, Health Education Unit, Tallinn Univ of Educational Sciences, Estonia & Pain Relief Unit, Helsinki Univ Central Hospital, Finland

Aim of Investigation: To evaluate the effectiveness ofvenlafaxine in neuropathic pain following treatment of breast cancer.

Methods: 15 women who had previously treated for breast cancer were recruited. They were free of relapses and the intensity of neuropathic pain was at least moderate (^30/100 on the VAS). The study was a randomized, double-blind, placebo controlled crossover study. The 2 treatments (4 weeks each) were separated by a 2-week washout period. The dose ofvenlafaxine was increased to 75 mg. Pain intensity and relief, adverse effects and mood were studied using a computerised pain programme developed at the Karo-linska Hospital, Stockholm and Janssen-Cilag. Venous blood samples were collected at the end of each treatment.

Results: One patient discontinued because of adverse effects, 2 patients because of non-compliance. Two patients remained on the daily dose of37.5mg. At the baseline the maximum pain intensity was 55/100 and the minimum pain intensity 8/100. Venlafaxine significantly reduced the maximum pain intensity compared with placebo (p<0.05) but there was no difference in the minimum pain intensity. There were no significant differences in mood and adverse effects between the treatments. The median serum concentration of venlafaxine was 42.5 nmol/1 and 0-desmethylvenlafaxine was 334 nmol/1.

Conclusions: Venlafaxine effectively relieved neuropathic pain in patients operated for breast cancer. One patient discontinued and 2 patients could increase the dose only to 35 mg because of adverse effects. The rest of the patients had no significant adverse effects during the study.

ELECTRODIAGNOSTIC EVALUATION OF NERVE BLOCK IN PATIENTS WITH CHRONIC PAIN.

Keiko Tsuji. Makoto Fukuzaki, Koji Sumikawa, Anesthesiology of Uresino National Hospital

Aim of Investigation: Peripheral sensory nerve dysfunction was analyzed with current perception threshold (CPT) in patients with chronic pain. The therapeutic effects of nerve block were also evaluated with CPT.

Methods: Fourteen patients underwent CPT analysis at 3 regions, i.e., impaired region, opposite side of the region and normal region in the same side, before and 3 hrs after nerve block. CPT were measured by Neurometer* CPT/C (Toyo Medic) and analyzed by Neural DB II on range analysis, within CPT ratios, and between sites CPT ratios.

Results: Eight patients with postherpetic neuralgia (PHN) had hy-poesthesia of Aft fiber at impaired region, and four of them showed hypoesthesia at opposite side, too. Nerve block restored CPT to normal range in five of them. Three of 4 patients with disc hernia had no abnormal CPT, but one patient with allodynia showed hypoesthesia ofA/?and A5, of which A/? function restored after nerve block. One of 2 patients with failed back syndrome with allodynia had hyperesthesia, but showed no change in CPT, although the symptom was improved by nerve block.

Conclusion: In neuropathic pain, hypoesthesia of A/? analyzed by CPT could recover after nerve block, whereas hyperesthesia would show no change in CPT in spite of improved symptom after nerve block.

ABNORMAL MOVEMENTS IN REFLEX SYMPATHETIC DYSTROPHY (CRPS): A PSEUDONEUROLOGI-CAL SIGN.

Renato Verdugo. Jose Ochoa, Univ. de Chile and Good Samaritan Hospital, Portland, OR 97210

Aim of Investigation: Delineate nature and mechanisms of movement disorders in Reflex Sympathetic Dystrophy (Complex Regional Pain Syndrome I, CRPS I) and Causalgia (CRPS II).

Methods: Patients (58) fulfilling diagnostic criteria for CRPS and displaying abnormal movements underwent comprehensive clinical and neurophysiological evaluation of central and peripheral motor, sensory and autonomic systems and investigation of their symptoms through placebo controlled diagnostic blocks.

Results: There was no patient whose chronic pain and movements could be attributed to overt nerve injury (CRPS II). All were diagnosed as CRPS I. They presented spasms (35 patients), coarse tremor (9), irregular jerks (5), choreiform movements (1) or combinations of the above (8). Abnormal movements were characteristically bizarre. Remarkably, in addition to lack of evidence of nerve injury, the patient's central motor and sensory pathways also responded normally to rigorous neurophysiological testing. Additionally, all patients displayed one or more signs ofpsychogenic dysfunction in relation to their painful neurological display, in cluding: 1) muscle weakness due to interrupted willful drive (Emg) 2) disappearance of abnormal movement with distraction, 3) extreme fluctuations in the distribution and character of movements, 4) abolition of the movements with placebo, 5) relief of muscle weakness by placebo, 6) non anatomical cutaneous hypoesthesia, 7) reversal of hypoesthesia through inert or active placebo effect, 8) normal two point discrimination threshold in spite of profound tactile hypoesthesia, 9) cure with psychotherapy in three patients and 10) documentation of malingering in two.

Conclusions: Prior etiologic hypotheses pointing at psychogenesis behind these abnormal movements are supported by the present study which, in addition, highlights the pseudoneurological character of the sensory and motor symptomatology in these patients.

TRIGEM1NAL POSTHERPETIC NEURALGIA: A POSTMORTEM STUDY

CPN Watson'. S Nag', J Dostrovsky', M Devor², R Midha', T Hokfelt , Univ of Toronto, Hebrew Univ-Jerusalem, Karolinska Inst-Sweden

Aim of Investigation: This is the first autopsy examination of postherpetic neuralgia (PHN) of the ophthalmic division of the trigemi-nal nerve.

Method: The literature with regard to postmortem studies of herpes zoster ophthalmicus will be reviewed. Most of these studies were of acute zoster patients or those who did not clearly suffer PHN. They did however demonstrate pathology in the gasserian ganglion, in the peripheral nerve, and centrally.

Results: This case was striking because of the presence of severe involvement of the ophthalmic nerve and absence of any signs of change from the gasserian ganglion through to the thalamus.

Conclusions: These findings are at variance with the data in spinal cases of PHN and from other cases of ophthalmic herpes zoster. Further studies of the ophthalmic division in this case will be presented.

WHAT IS THE MCGILL PAIN QUESTIONNAIRE MEASURING IN PHANTOM LIMB PAIN.

Anne Whyte and Catherine Niven, Pain Research Unit, Dept of Nursing and Midwifery, Univ of Stirling, Stirling FK9 4LA, UK

Aim of Investigation: Much of the literature has focused on phantom limb pain has measured it at a single point in time and has not examined the stability of dimensions of phantom limb pain over time. The present study provides the only data examining chronic phantom limb pain.

Methods: Using a postal questionnaire, phantom limb pain was measured in 315 amputees using the MPQ and again one year later using the same instrument in a selected sample (89) of the original study population. Hourly pain ratings on a visual analogue scale were also collected from the second study sample over the course of one week.

Results: The data showed that the average intensity of phantom limb pain, as measured by the MPQ was remarkably similar across phase one and two of this study. Data from the diary study however, suggest it is unlikely that the same intensity of phantom limb pain would be reported on two occasions separated by one year. Indeed the most striking feature of this data was the lack of uniformity in the intensity and duration of episodes of phantom limb pain. The diary study results provide strong evidence of the variability in both duration and intensity of phantom limb pain episodes.

Conclusions: Given the episodic nature of phantom limb pain and the variation in intensity reported in diary study, it is unlikely that comparable levels of phantom limb pain would be recorded by individuals at the two data collection points over the course of the study year. Therefore what is the McGill Pain Questionnaire is actually measuring in this population?

STUDY TO EVALUATE THE EFFICACY OF PAIN RELIEF DUE TO TENS OR ACUPUNCTURE OR BOTH ADJUVANT THERAPIES COMPAIRED TO A STANDARDIZED DRUG THERAPY IN AMPUTATION PAIN OF THE LOWER LIMB.

Alfred Gneger. Univ. of Vienna, Dep. OfTraumatology, A-1090, Karin Rcif*, Thomas Eder*, Martin Morscher*, Peter Guglia*, *Rehabcenter St. Andra/Zicksee, A-7161

Aim of Investigation: To investigate the relationship between pain reduction produced either by TENS or acupuncture or both in phantomic pain after amputation of the lower limb, compared to standardized pain therapy (drugs, physio- and magnetic field therapy). Furthermore to evaluate if there is drug reduction by the patients themselves and if the possible reduction of amputation pain at long term interval (3, 6, 12 month), induced by TENS or/and acupuncture, is significant.

Methods: Till 31th Dec 1998 72 patients (45% of the prospective, randomised, monocentric, study population) were study enclosed as randomised. Each patient was treated with the same morphine derivate and received the same rescue medication (drops) for 3 weeks. All patients were divided into 4 groups and treated either with drugs (GI) or adjuvant with TENS (G II - 3 times a day) or acupuncture (G III - 6-10 times body acupuncture and ear acupuncture during the interval) or both (GIV).

Results: Till 31st Dec 1998 we treated 72 patients (35% women, 65 % men with an average age of 64 years) in 4 groups. The mean VAS score in G I patients during observation period was 3.54, in Gil 4.36, in GIII 3.38 and in G IV 4.12. 16 patients (11.5%) stopped magnetic field therapy because of traumatic pain-intensification (VAS-score increasing about 3 or more points during or within 1 hour after treatment). 19 patient (13.7%) never took any drugs (3.6%) reduced their drug consumption about 50% and 8 (5,8%) about 33.3 %. Among those 32 (23%) there were only 6 (4,3%) G 1 patients.

Conclusions: Subjective pain relief and/or drug reduction due to alternative pain therapy as TENS and/or acupuncture. Pain intensification in combination with magnetic field therapy Acknowledgments: supported in part by Nycomed Austria, Tn-esterstr.50,A-1102

THEEFFECTOFMEMANT1NE,ANMDA-RECEPTOR ANTAGONIST ON POSTAMPUTATION STUMP AND PHANTOM PAIN.

Lone Nikolajsen. Hanne Gottrup, Anders D. Christensen* Troels Staehelin Jensen, Danish Pain Research Center, Univ ofAarhus, 8000 Aarhus C, Denmark

Aim of Investigation: To examine ifMemantine relieves post-amputation pain, allodynia and hyperalgesia. Methods: The design was double-blinded, crossover and placebo-controlled. Seventeen amputees had Memantine/placebo tablets daily for 5 weeks and another 5 weeks treatment period with the opposite drug. Stump and phantom pain was assessed daily in the 2 treatment periods using a VAS 0-100. Before and after each treatment period McGill Pain Questionnaire was used for assessment of pain and stump sensibility was measured (cold and brush evoked allodynia, touch and pain detection thresholds, wind-up-like pain). Blood samples were taken for analysis ofMemantine.

Results and Conclusion: Results will be available at the Congress.

Acknowledgments: Merz & Co., Frankfurt am Main, Germany delivered the Memantine tablets and analysed the blood samples.

MOTOR CORTEX STIMULATION FOR THE CENTRAL AND THE PERIPHERAL DEAFFERENTATION PAIN

Youichi Saitoh. Masahiko Shibata, Shun-ichiro Hirano*, Masayuki Hirata*, Takashi Mashimo, Toshiki Yoshimine*, Depts ofNeuro-surgery and Anesthesiology, Osaka Univ. Med. Sch., Suita, Osaka 565-0871,Japan

Aim of Investigation: We tested a modified motor cortex stimulation protocol for treatment ofcenral and peripheral types ofdeaf-ferentation pain.

Methods: Four patients with thalamic pain and four with peripheral deaffcrentation pain were studied. Preoperative pharmacologic tests of pain relief were performed with phentolamine, lidocaine, ketamine, thiopental, and placebo. In 5 patients we placed a 20-electrode grid in the subdural space to determine the best stimulation point for pain relief over a few weeks prior to definitive placement of a 4-electrode array. In 3 patients 4-array electrode was implanted in the inter-hemispheric fissure as a one-stage procedure to treat lower extremity pain. In 2 patients with pain extending from the extremity to the body, Mattrix devices were implanted to drive 2 electrodes.

Results: Six of 8 patients showed pain reduction (two excellent, two good, and two fair cases) with motor cortex stimulation. No correlation was apparent between pharmacologic test results and effectiveness of motor cortex stimulation. Peripheral deafferenta-tion pain including 2 cases of phantom limb pain and 2 ofbrachial plexus injury showed pain relief from motor cortex stimulation, with excellent results in 2 cases.

Conclusion: Test stimulation with a subdural multi-electrode grid was helpful in locating the best stimulation point for pain relief. Motor cortex stimulation may be effective for treating peripheral as well as central deafferentation pain.

NATIONAL AUDIT OF THE PAIN MANAGEMENT OF AMPUTEES.

Vanessa Skelton. Magdi Hanna, Dept of Anaesthesia, King's College Hospital, Denmark Hill, London SE5 9RS

Aim of Investigation: To determine the existence or otherwise of pain management policies for amputees. Method: A questionnaire was sent to consultant members of the Vascular Surgical Society and medical members of the Pain Society. A small follow-up study was sent to amputee rehabilitation units.

Results: 290 responses from 162 hospitals were received of which 214 were completed. 39.4% of respondents knew of a pain management policy before amputation; 47.6% had no policy and 15.9% didn't know. Hospitals treating the largest number of patients with peripheral limb ischaemia were more likely to have an established policy and have pain teams or clinics. Of existing policies, 46.1 % used pre-operative epidural analgesia; 60.3% of these maintained epidural analgesia for 2 - 3 days. 50.9% of respondents had a policy for the use ofsympathectomies mainly for the treatment of patients with critical limb ischaemia associated with rest pain, un-suitability for surgery or ischaemic ulcers. A median of 40% of amputees experienced phantom limb pain (PLP) and 80% phantom sensation. Antidepressants and anticonvulsants were the most commonly used treatments for PLP (62.4%). 61.5% of rehabilitation units have a pain management policy for PLP, with antidepres-sants and anticonvulsants most commonly used.

Conclusions: Nearly 40% of hospitals and 62% of rehabilitation units in the UK have a pain management policy for the treatment of amputees. Policies are more likely in hospitals with acute pain teams. Antidepressants and anticonvulsants are the most commonly used treatment for phantom limb pain. Despite the high incidence of phantom pain and sensation, few patients are referred to chronic pain clinics!

CASE SERIES. MIDAZOLAM FOR THE TREATMENT OF PHANTOM PAIN EXACERBATION

C. Vichitrananda.* S. Pausawasdi. Pain clinic, Ramathibodi Hospital Faculty Of Medicine, Mahidol Univ, Bangkok 10400, Thailand

Aim of Investigation: The phantom pain is one of the most difficult symptoms to manage. The severe exacerbation of phantom pain is clinical challenge.

Methods: Descriptive study of clinical cases of successful treatment of phantom pain exacerbation with intravenous midazolam.

Results: Casel- A 57 year-old man with the right below-knee amputation 3 years ago due to chronic arterial occlusion. He experienced occasional phantom discomfort that needed no treatment. He was scheduled for debridement of chronic ulcer over his left foot. Spinal anesthesia with 10 mg bupivacaine was done. After the complete anesthesia to T10 level, the patient complained of severe unbearable pain shooting down over his amputated right leg. He was extremely restless while the surgeon was operating on pain-free left leg. Attempts were made to relieve the patient's distress by iv morphine 3 mg with no improvement. Increment dose ofiv midazolam 3 mg was given, the phantom pain disappeared. He was not asleep and able to freely communicate. After the spinal anesthesia wore off, he did not experience the phantom pain. Case 2 - A 24-year-old woman with the phantom pain due to traumatic amputation of her right hip for 2 months. She was treated with intravenous xylocaine 3 mg/kg daily, amitryptyline 50 mg hs, baclofen 150 mg tid, and paracetamal 1 gm q 6 hrs which afforded pain relief from VAS 9 to 3. On the third day, after 6 hours ofiv xylocaine infusion, the patient experienced severe phantom pain exacerbation. Attempts to relieve her pain by iv morphine 4 mg offered no relief. Increment dose ofiv midazolam 5 mg was given. The pain diminished and disappeared in 3 minutes. She was able to sit up and ate her meal. After 1 month her phantom pain was improved she had another episode of phantom pain exacerbation, 5 mg iv midazolam offered the complete pain relief.

Conclusion: Phantom pain may be caused by abnormal firing of the central nervous system. Benzodiazepine diminishes facilitation and enhances GABA-ergic inhibition at the synapses throughout the central nervous system. Exacerbation of phantom pain can be abolished by iv midazolam 3-5 mg.

9th WORLD CONGRESS ON PAIN, 1999, Vienna, Austria, p.188 - 194