Difficulties in diagnosing neuropathic pain in routine clinical practice support the need for validated and easy-to-use diagnostic tools. The DN4 neuropathic pain diagnostic questionnaire aims to discriminate neuropathic pain from nociceptive pain, but needs clinical validation. A total of 269 patients with chronic pain in three pain clinics were included in the study of which 248 had analyzable data. The mean duration of pain was 4.9 years. The most frequent etiologies were posttraumatic (36%), (pseudo) radicular (14%), and mechanical back pain (12%). The mean intensity of pain at visit was 5.6 on a 0-10 scale. Hundred and ninety-six of 248 patients had an identical pain diagnosis from both physicians: 85 had neuropathic pain, 57 had nociceptive pain, and 54 had mixed pain. Among patients with identical diagnoses of neuropathic or nociceptive pain, using a receiver operating characteristic curve analysis, the area under the curve (AUC) was 0.81 for the DN4 7-item and 0.82 for the 10-item version. A cutoff point of 5/10 for the full questionnaire resulted in a sensitivity of 75% and a specificity of 79%, while a cutoff point of 4/7 for the partial questionnaire resulted in a sensitivity of 74% and a specificity of 79%. The items "brushing," "painful cold," and "numbness" were most discriminating. The DN4 is an easy-to-use screening tool that is reliable for discriminating between neuropathic and nociceptive pain conditions in daily practice. Item-specific scores provide important information in addition to the total score.

Pain in patients with cancer can be refractory to pharmacological treatment or intolerable side effects of pharmacological treatment may seriously disturb patients' quality of life. Specific interventional pain management techniques can be an effective alternative for those patients. The appropriate application of these interventional techniques provides better pain control, allows the reduction of analgesics and hence improves quality of life. Until recently, the majority of these techniques are considered to be a fourth consecutive step following the World Health Organization's pain treatment ladder. However, in cancer patients, earlier application of interventional pain management techniques can be recommended even before considering the use of strong opioids. Epidural and intrathecal medication administration allow the reduction of the daily oral or transdermal opioid dose, while maintaining or even improving the pain relief and reducing the side effects. Cervical cordotomy may be considered for patients suffering with unilateral pain at the level below the dermatome C5. This technique should only be applied in patients with a life expectancy of less than 1 year. Plexus coeliacus block or nervus splanchnicus block are recommended for the management of upper abdominal pain due to cancer. Pelvic pain due to cancer can be managed with plexus hypogastricus block and the saddle or lower end block may be a last resort for patients suffering with perineal pain. Back pain due to vertebral compression fractures with or without pathological tumor invasion may be managed with percutaneous vertebroplasty or kyphoplasty. All these interventional techniques should be a part of multidisciplinary patient program.

The addition of 15 microg clonidine to 5 mg of intrathecal hyperbaric bupivacaine prolongs the duration of motor block and improves the quality of the block.

SUMMARY1. Myogenic responses may account for control of organ blood flow. The study of these responses without interference from the organ requires an isolation technique for vessels which contribute significantly to flow resistance. This study reports on experiments on isolated small mesenteric arteries.2. Distal rat mesenteric arcade arteries and first-order branches (diameter range 145-365 ,um, mean 293 ,um) were manually dissected and cannulated using a doublebarrelled micro-cannula. Luminal cross-sectional area of these vessels was continuously monitored by means of a fluorescence technique.3. Nine out of eighteen vessels developed basal tone at 80 mmHg distending pressure, resulting in a 45-2 + 5-1 % (mean + S.E.M) decrease of cross-sectional area.Tone was induced in the other vessels by 0-3-1 tim-noradrenaline, resulting in a 59-5 + 741 % decrease in cross-sectional area.4. In vessels with either spontaneous or induced tone, stepwise changes of pressure resulted in passive effects, followed by myogenic responses.5. Steady-state pressure-cross-sectional area relations of vessels with basal tone showed a significant negative slope (-0-5% mmHg-'), while pressure-crosssectional area relations of vessels with induced tone were essentially flat between 40 and 120 mmHg.6. Five vessels with basal tone and eight vessels with induced tone developed vasomotion at 80 mmHg. Frequencies of spontaneous and induced vasomotion were 14 (range 4-31) and 21 (9-25) cycles min-' respectively. Amplitudes were 5 (1-10) and 8 (3-17)% of the passive cross-sectional area. In both groups, frequency was positively, and amplitude negatively correlated with pressure.7. These data show that myogenic responses are induced by wall stress, rather than by distension of the vascular wall. Basal tone is not a prerequisite for the appearance of myogenic responses.MS 8293