Local anesthetic effect of intrathecal normal saline.

The effects of intrathecally administered normal saline have been studied in patients undergoing graduated spinal anesthesia. The injection of 5 or 10 ml volumes resulted in segmental hypesthesia to pin-scratch and cold stimuli extending from the lower thoracic to the sacral dermatomes. There was also partial sympathetic block evidenced by a diminished psychogalvanic skin reflex. The sites and possible mechanisms of action of saline are discussed; its use as placebo in graduated spinal anesthesia is questioned. It is concluded that normal saline acts as a weak local anesthetic when injected intrathecally.

Analyzing chronic low back pain: the relative contribution of pain coping strategies.

Sixty-two chronic low back pain patients were administered the Coping Strategies Questionnaire (CSQ) to assess the frequency of use and perceived effectiveness of a variety of cognitive and behavioral pain coping strategies. Analysis of individual variables revealed that CSQ factors, gender, physical examination findings, and chronicity of pain had significant effects on one or more of a series of pain, psychological distress or behavioral measures. To assess the relative contribution of each of these variables hierarchical stepwise regression analyses were carried out. These analyses revealed that the Helplessness factor of the CSQ explained 50% of the variance in psychological distress (Global Severity Index of the SCL-90R), and 46% of the variance in depression (Beck Depression Inventory). Patients scoring high on this CSQ factor had significantly higher levels of psychological distress. None of the demographic or medical status variables explained a significant proportion of variance in the psychological distress measures. The Diverting Attention and Praying factor of the CSQ explained a moderate (9%), but significant amount of variance in pain report. Patients scoring high on this factor had higher scores on the McGill Pain Questionnaire. Coping strategies were not strongly related to pain behavior measures such as guarding or uptime. A consideration of pain coping strategies may allow one to design pain coping skills training interventions so as to fit the needs of the individual low back pain patient.

A study of psychophysical scaling in chronic pain patients.

Chronic pain patients were asked to psychophysically scale two sets of word descriptors (intensity and unpleasantness) using a crossmodality matching procedure with line length and numerical estimates. In 22 patients (group I) descriptor scaling was performed once, in another 20 patients (group II) the procedure was repeated 3 times. 72.7% of patients in group I obtained a correlation of 0.9 or higher when scaling intensity descriptors, but only 18.2% obtained this correlation when scaling unpleasantness words. In group II, an average of 85% of patients reliably scaled intensity words, but only 50% could do so for the unpleasantness descriptors. Patients who reliably judged unpleasantness descriptors generally exhibited a higher level of psychological distress (SCL-90 R). Numerical estimates assigned by patients to individual word descriptors showed a smaller range than obtained from experimental pain studies. There was unequal spacing of values of adjacent descriptors with clustering of words in the low and high ends of the continuum and large gaps in midrange. Results indicate that chronic pain patients in general show a higher incidence of impairment in rendering proportional judgments than a healthy population. In addition, they are more likely to judge pain reliably on an intensity than on an unpleasantness dimension. The difference in performance between scales persists in spite of training and could not be explained by medical history, drug intake, or demographic characteristics. Patients who are unable to render reliable judgments are easily identified. For optimal clinical use words clustering close together should be combined and additional words should be added describing midrange intensities. Conversely, psychophysical scaling techniques may be used to calibrate category or analogue scales of pain.

Alterations in cerebrospinal fluid concentrations of somatostatin-like immunoreactivity in chronic pain patients.

Concentrations of somatostatin-like immunoreactivity in cerebrospinal fluid were significantly reduced in chronic pain patients compared to control patients without chronic pain. This difference was not influenced by demographic or clinical characteristics. Somatostatin has been shown to be a neurotransmitter in animal nociception; pharmacologic doses of this substance have moderated human pain. Our findings provide evidence that somatostatin may be involved in the pathogenesis of the chronic pain state.

Long-term use of narcotic/antidepressant medication in the management of phantom limb pain.

The successful management of 5 consecutive patients with intractable phantom limb pain is described. The main therapy is a combination of a narcotic and antidepressant. Medication remained effective during the average observation time of 22 months. There were no signs of habituation or addiction. We conclude that narcotics can be safely and successfully utilized for long-term management of phantom limb pain.

Chronic pain and depression. I. Classification of depression in chronic low back pain patients.

An association between chronic pain and depression has been recognized for a long time. However, the exact nature of this relationship remains unclear. The authors studied 71 patients for affective disorders and schizophrenia-lifetime version (SADS-L). Based on the interviews, we were able to identify 31 patients with major depression, 8 patients with minor depression and 18 with intermittent depressive disorder as defined by Research Diagnostic Criteria. Item analysis using the Hamilton Depression Rating Scale and the Montgomery-Asberg Depression Rating Scale showed that the items did not discriminate in patients with major depression the presence of organic findings. However, most of the items significantly discriminated between the various types of depression and patients without depression. The occurrence of clearly defined depression points to several avenues of research aimed at clarifying the incidence etiology and treatment of depression in these patients.

Chronic pain and depression. II. Symptoms of anxiety in chronic low back pain patients and their relationship to subtypes of depression.

The relationship between anxiety and chronic pain has been poorly studied. The authors studied the occurrence of symptoms of anxiety in chronic low back pain patients. Anxious mood and other symptoms of anxiety were commonly seen in patients with chronic low back pain. Symptoms of anxiety were more common in patients with depression, especially those with major depression. Anxious mood, tension and general somatic symptoms of the sensory type were more common than any other type of anxiety symptoms. The authors discuss the potential role of anxiety in chronic pain patients.

CSF monoamine metabolites in chronic pain.

Metabolites of selected neurotransmitters (5-HIAA, HVA and DOPAC) and beta-endorphin were measured in the CSF of 39 chronic pain patients and compared to controls. Twelve of the pain patients also fulfilled criteria for major depression. The concentration of 5-HIAA was increased in female but not male pain patients; there was no significant difference in the CSF concentrations of HVA and DOPAC. The presence of depression did not influence the concentrations of neurotransmitters. No correlation was found between the concentrations of monoamine metabolites and beta-endorphin. However, there was a positive correlation between 5-HIAA and HVA in controls and chronic pain patients without depression but not in depressed patients. It is concluded: chronic pain states are associated with elevation of CSF 5-HIAA in female patients; depression abolishes a positive correlation between 5-HIAA and HVA.