Standard Pain Treatment Research Articles

The Moderating Effect of Obesity on Cognitive–Behavioral Pain Treatment Outcomes

To assess the effects of body mass index on cognitive-behavioral pain treatment outcomes for chronic low back pain. Retrospective analyses of data from a clinical trial were performed, with body mass index used to divide patients into obese and non-obese groups for comparison. VA medical center outpatient clinic. Veterans (N = 74) receiving outpatient care through the VA. Delivery of a 10-week cognitive-behavioral pain treatment intervention. The Numerical Rating Scale (pain intensity), Roland Morris Disability Questionnaire (disability), Veteran's SF-36 (health-related quality of life), and Beck Depression Inventory (emotional functioning) were administered pre- and post-treatment. The study included 42 obese and 32 non-obese participants, most of whom were male (89%). The average body mass index was 32.44 kg/m², with average pain intensity rated as 6.59 out of 10. There were no pre-treatment differences in outcome measures between the groups. Repeated measures ANOVAs revealed main effects of Time on all but one outcome (Mental Component score), indicating that the cognitive-behavioral interventions were largely effective. However, Time-body mass index (BMI) group interactions revealed that non-obese participants showed greater improvement following treatment than did their obese counterparts on measures of disability (P < 0.05), physical aspects of quality of life (P < 0.01), and emotional functioning (P < 0.05). Standard cognitive-behavioral pain treatment did not yield comparable outcomes for obese and non-obese participants. Results suggest a potential moderating role of BMI in low back pain outcomes. Future work with other pain conditions, including examination of potential mechanisms through which BMI impacts treatment outcomes, is recommended.

Improvement of pain related self management for oncologic patients through a trans institutional modular nursing intervention: protocol of a cluster randomized multicenter trial

BackgroundPain is one of the most frequent and distressing symptoms in cancer patients. For the majority of the patients, sufficient pain relief can be obtained if adequate treatment is provided. However, pain remains often undertreated due to institutional, health care professional and patient related barriers. Patients self management skills are affected by the patients' knowledge, activities and attitude to pain management. This trial protocol is aimed to test the SCION-PAIN program, a multi modular structured intervention to improve self management in cancer patients with pain.Methods240 patients with diagnosed malignancy and pain > 3 days and average pain ≥ 3/10 will participate in a cluster randomized trial on 18 wards in 2 German university hospitals. Patients from the intervention wards will receive, additionally to standard pain treatment, the SCION-PAIN program consisting of 3 modules: pharmacologic pain management, nonpharmacologic pain management and discharge management. The intervention will be conducted by specially trained oncology nurses and includes components of patient education, skills training and counseling to improve self care regarding pain management beginning with admission followed by booster session every 3rd day and one follow up telephone counseling within 2 to 3 days after discharge. Patients in the control group will receive standard care.Primary endpoint is the group difference in patient related barriers to management of cancer pain (BQII), 7 days after discharge. Secondary endpoints are: pain intensity & interference, adherence, coping and HRQoL.DiscussionThe study will determine if the acquired self management skills of the patients continue to be used after discharge from hospital. It is hypothesized that patients who receive the multi modular structured intervention will have less patient related barriers and a better self management of cancer pain.Trial RegistrationClinicalTrials NCT00779597

Improving Postoperative Pain Management

DESPITE recent advances in our understanding of the physiology of acute pain, the development of new opioid and nonopioid analgesics and novel methods of drug delivery, and more widespread use of pain-reducing minimally invasive surgical techniques, pain after surgical procedures remains a challenge for many practitioners. Not surprisingly, recent surveys in the United States and Europe have emphasized the insufficient quality of postoperative pain management and the need for further improvements. The increasing implementation of standardized pain evaluation and treatment protocols, and the use of multimodal analgesic techniques, are hopeful signs that improvements in pain management are likely to continue in the years ahead. What then are the major unresolved issues in the management of acute postoperative pain, and how should surgical patients bemanaged based on the available evidence from the peer-reviewed medical literature?

Ketamine produces effective and long-term pain relief in patients with Complex Regional Pain Syndrome Type 1

Complex Regional Pain Syndrome Type 1 (CRPS-1) responds poorly to standard pain treatment. We evaluated if the N-methyl- d-aspartate receptor antagonist S(+)-ketamine improves pain in CRPS-1 patients. Sixty CRPS-1 patients (48 females) with severe pain participated in a double-blind randomized placebo-controlled parallel-group trial. Patients were given a 4.2-day intravenous infusion of low-dose ketamine ( n = 30) or placebo ( n = 30) using an individualized stepwise tailoring of dosage based on effect (pain relief) and side effects (nausea/vomiting/psychomimetic effects). The primary outcome of the study was the pain score (numerical rating score: 0–10) during the 12-week study period. The median (range) disease duration of the patients was 7.4 (0.1–31.9) years. At the end of infusion, the ketamine dose was 22.2 ± 2.0 mg/h/70 kg. Pain scores over the 12-week study period in patients receiving ketamine were significantly lower than those in patients receiving placebo ( P < 0.001). The lowest pain score was at the end of week 1: ketamine 2.68 ± 0.51, placebo 5.45 ± 0.48. In week 12, significance in pain relief between groups was lost ( P = 0.07). Treatment did not cause functional improvement. Patients receiving ketamine more often experienced mild to moderate psychomimetic side effects during drug infusion (76% versus 18%, P < 0.001). In conclusion, in a population of mostly chronic CRPS-1 patients with severe pain at baseline, a multiple day ketamine infusion resulted in significant pain relief without functional improvement. Treatment with ketamine was safe with psychomimetic side effects that were acceptable to most patients.

Effects of oral pregabalin and aprepitant on pain and central sensitization in the electrical hyperalgesia model in human volunteers

Central sensitization is an important mechanism of neuropathic pain; its human models could be useful for early detection of efficacy of novel treatments. The electrical hyperalgesia model invokes central sensitization by repetitive stimulation of the skin. To assess its predictive value, we have investigated pregabalin, a standard neuropathic pain treatment, and aprepitant, an NK(1) antagonist, as an example of a drug class active in animal models but not in neuropathic pain patients. Furthermore, we explored if combinations of either of these drugs with the COX-2 inhibitor parecoxib could improve its efficacy. This was a double-blind, two-period, placebo-controlled study using incomplete block design. Thirty-two healthy volunteers received either oral pregabalin (titrated to 300 mg) or aprepitant (titrated to 320 mg), or matching placebo over 6 days before testing. Sensitization was assessed over 3 h; at 2 h, subjects received either parecoxib (40 mg) or saline i.v. Pregabalin significantly reduced the areas of punctate mechanical hyperalgesia and dynamic touch allodynia vs placebo (both P < 0.0001); no significant reduction in the area of hyperalgesia or allodynia vs placebo was observed with aprepitant. In the pregabalin + parecoxib treated group, the area of allodynia was significantly reduced (P < 0.0001) and the area of hyperalgesia insignificantly attenuated (P = 0.09) vs placebo + parecoxib; no efficacy improvement was observed with aprepitant + parecoxib. The model can serve to predict analgesic efficacy in early human development and investigate the mechanism of action. The model could also be used to explore efficacy of analgesic combinations to provide a rationale for patient studies.

Preoperative analgesia with local lidocaine infiltration for abdominal hysterectomy pain management

Objective To evaluate the impact of preemptive local analgesia at the incision site in reducing pain in women undergoing abdominal hysterectomy for a benign myomatous uterus. Study design In this prospective, randomized, double-blinded, placebo-controlled study, 20 mL of 1% lidocaine or 0.9% saline was injected at the abdominal incision site prior to the performance of the hysterectomy. Thirty-two women were enrolled in the study, 16 received preemptive analgesia while 14 were treated by placebo; 2 were excluded. All operations were performed under general anesthesia. The standard postoperative pain treatment consisted of oral analgesia with ibuprofen (400 mg) in liquid-filled capsules. Morphine (10 mg) was used for rescue analgesia. Pain intensity was self-evaluated with the use of a 100 mm visual analog scale. Results Compared to the placebo group, women who received preemptive analgesia with lidocaine 1% perceived a significant reduction in postoperative pain in the first hours after surgery (2 h: 50.1 ± 27.9 versus 70.6 ± 22.6, p = 0.043; 5 h: 42.5 ± 25.2 versus 64.6 ± 28.3, p = 0.043; 8 h: 31.2 ± 22.4 versus 53.3 ± 30.3, p = 0.031). Conclusion Preemptive analgesia with lidocaine 1% is a simple, cheap and efficient mode to reduce pain in the first hours after hysterectomy.

Minimal immunoreactive plasma β-endorphin and decrease of cortisol at standard analgesia or different acupuncture techniques

Acupuncture has been claimed to be associated with activation of the endogenous antinociceptive system. The analgesic effects of acupuncture have been ascribed to beta-endorphin interacting with opioid receptors. However, firstly, the release of beta-endorphin into the blood has been proven to be induced by stress, i.e. under dysphoric conditions, and, secondly, if released under stress, beta-endorphin has been shown not to be analgesic. Our aim was to test whether beta-endorphin immunoreactive material is released into the cardiovascular compartment during acupuncture comparing the most frequently used types of acupuncture with standard pain treatment under apparently low stress conditions. This prospective study included 15 male patients suffering from chronic low back pain. beta-Endorphin immunoreactive material and cortisol were measured in the plasma of patients who underwent, in random order, therapy according to a standard pain treatment, traditional Chinese acupuncture, sham acupuncture, electro acupuncture and electro acupuncture at non-acupuncture points before, at and after the treatment. Statistical analysis was performed using two-way ANOVA with repeated measures. A decrease in plasma cortisol concentration measured over the five treatment protocols was highly significant (P < 0.001). The beta-endorphin immunoreactive material concentrations in plasma were minimal at all times and in all treatment conditions. The influence of treatments by various acupuncture procedures on cortisol and beta-endorphin immunoreactive material plasma concentrations over the three time points was not significantly different. beta-endorphin immunoreactive material in blood is not released by any type of acupuncture as tested under low stress conditions.

N-Acetylaspartate concentrations in the thalami of neuropathic pain patients and healthy comparison subjects measured with 1H-MRS

We investigated the absolute concentration of N-acetylaspartate (NAA) in the thalami of neuropathic pain patients and healthy comparison subjects by single-voxel proton magnetic resonance spectroscopy ((1)H-MRS). (1)H-MRS was performed with a 1.5-T MR system on a voxel in the thalamus bilaterally in 9 neuropathic pain patients and 14 healthy control subjects. We measured the absolute concentration of NAA using a linear combination model. The NAA concentration in the thalamus decreased significantly on the contralateral side in seven patients and on the ipsilateral side in two patients, as compared with the mean NAA concentration of the healthy control subjects. The NAA concentrations in two patients who did not respond to standard pain treatments were extremely decreased. Our results using (1)H-MRS suggest that neuropathic pain seems to be associated with an abnormal balance of the neural activity in the thalamus. The NAA concentration of the thalamus may be related to the efficacy of therapy. (1)H-MRS may serve as a useful noninvasive tool for evaluating thalamic neural activity in neuropathic pain patients.

Possible involvement of brain-derived neurotrophic factor in the antinociceptive effect of antidepressants in neuropathic pain

Neuropathic pain, a chronic pain state caused by injury to the nervous system, usually responds poorly to standard pain treatment. Antidepressants have been used to treat neuropathic pain, and animal and clinical studies have showed beneficial effects. However, the mechanisms underlying antidepressant antinociceptive effect in neuropathic pain are still unknown. Brain-derived neurotrophic factor (BDNF), a member of the neurotrophic factor family, can modulate synaptic plasticity and neurotransmitter release across multiple neurotransmitter systems. Recent animal and human studies have demonstrated that antidepressants can increase central as well as plasma BDNF levels. In addition: (1) BDNF is produced by a subset of primary sensory neurons that are located in the dorsal root ganglion; (2) BDNF levels change in animal models of neuropathic pain; (3) BDNF can indirectly depress sensory neuron transmission in the dorsal horn. From these findings, it is proposed that BDNF may play an important role in the antidepressant antinociceptive effect in neuropathic pain. The notion of BDNF mediating the therapeutic mechanisms of antidepressant in neuropathic pain may help to select the specific type and the optimal dose of antidepressants for the treatment of neuropathic pain. Exploration of this hypothesis could provide a new direction in the treatment of neuropathic pain, as well as other pain disorders.

MULTIDISCIPLINARY PAIN ABSTRACTS: 35. Neurology (35)

The aim of the present case series was to examine whether changes in regional cerebral blood flow (rCBF) induced by electroconvulsive therapy (ECT) in the thalamus are related to the efficacy of ECT. Four chronic pain patients with complex regional pain syndrome (CRPS) type I (age 33 to 58 years) who had failed to respond to standard pain treatments received a course of ECT. To investigate the possible mechanisms of the analgesic effect of ECT on chronic CRPS type I, the authors measured significant changes in the rCBF of the thalamus using technetium‐99 methyl cysteinate dimer single photon emission computed tomography (99mTc ECD SPECT), before and after ECT and compared these values between responders and nonresponders. Two of four patients responded to ECT. 99mTc ECD SPECT showed that the mean contralateral thalamus‐to‐cerebellum ratio increased 11.5% after ECT compared with the ratio before ECT in the two responders, but remained unchanged in nonresponders. The results from the SPECT suggest that normalization of the balance of rCBF in the thalamus may be related to the analgesic efficacy of the ECT on CRPS type I.

Changes in regional cerebral blood flow in the thalamus after electroconvulsive therapy for patients with central post-stroke pain

AbstractThe aim of the present study was to examine whether changes in regional cerebral blood flow (rCBF) induced by electroconvulsive therapy (ECT) in the thalamus are related to the efficacy of ECT. Two chronic pain patients with central post-stroke pain (53 and 58 years old), who had failed to respond to standard pain treatments, received a series of ECT treatments. To investigate the possible mechanisms of the analgesic effect of ECT on chronic central poststroke pain, we measured changes in the rCBF of the thalamus using technetium-99m ethyl cysteinate dimer single photon emission computed tomography (99mTc ECD SPECT), before and after ECT. One patient responded to ECT treatment (response defined as a reduction in pain of at least 60% on the visual analogue scale), but the other patient had minimal clinical response to ECT. 99mTc ECD SPECT showed that the mean contralateral thalamusto-cerebellum ratio increased 9.5% after ECT, compared to the ratio before ECT in the responder, but remained unchanged...

Changes in regional cerebral blood flow in the thalamus after electroconvulsive therapy for patients with complex regional pain syndrome type 1 (preliminary case series)

Background and Objectives: The aim of the present case series was to examine whether changes in regional cerebral blood flow (rCBF) induced by electroconvulsive therapy (ECT) in the thalamus are related to the efficacy of ECT. Four chronic pain patients with complex regional pain syndrome (CRPS) type-1 (age, 33 to 58 years) who had failed to respond to standard pain treatments received a course of ECT. To investigate the possible mechanisms of the analgesic effect of ECT on chronic CRPS type-1, we measured significant changes in the rCBF of the thalamus using technetium-99m ethyl cysteinate dimer single photon emission computed tomography (99mTc ECD SPECT), before and after ECT and compared these values between responders and nonresponders. Results: Two of 4 (50.0%) patients responded to ECT treatment (response defined as a reduction of at least 60% on the visual analog scale [VAS]). 99mTc ECD SPECT showed that the mean contralateral thalamus-to-cerebellum ratio increased 11.5% after ECT compared with the ratio before ECT in the 2 responders, but remained unchanged in nonresponders. Conclusions: The results from the SPECT suggest that normalization of the balance of rCBF in the thalamus may be related to the analgesic efficacy of the ECT on CRPS Type-1. Reg Anesth Pain Med 2002;27:529-532.

Comorbid Psychiatric Disorders and Predictors of Pain Management Program Success in Patients With Chronic Pain.

BACKGROUND: This prospective investigation assessed success rates of a pain management program for patients with and without DSM-III-R Axis I and II psychiatric disorders. METHOD: Subjects included 40 consecutive patients with chronic pain who were referred to a physical therapy-oriented, "standard" pain management program. Serial ratings of pain levels were measured via a visual analogue scale (VAS) at baseline, weekly throughout a 12-week program, and during a follow-up interval 1 month after completion of the program. Weekly reports of hours of gainful employment were recorded. VAS scores and number of hours worked per week were combined into a measure of pain improvement. This dependent variable was used to compare groups of patients across psychiatric disorders diagnosed via the Diagnostic Interview Schedule (DIS). Percentages of patients in each diagnostic group who met minimal criteria for improvement were computed and compared. A chi-square analysis was conducted on success rates between patients with and without any Axis I disorder, any Axis II disorder, and any substance abuse/dependence disorder. RESULTS: Overall, 70% of patients (N = 28) were found to have a DIS psychiatric disorder. There were differences in improvement between patients with and without Axis I disorders and between those with and without Axis II disorders. The presence of a diagnosis was associated with significantly lower improvement rates (p <.05). CONCLUSION: Patients with chronic pain enrolled in this clinic had a high prevalence of comorbid psychiatric disorders, and these comorbid patients were less likely to improve with standard chronic pain treatment. In a population of patients seeking treatment for chronic pain, these results suggest a need for detection and diagnosis of psychiatric disorders and further research on the efficacy of psychiatric treatment interventions in chronic pain management.

A case of central post-stroke pain with beneficial response to electroconvulsive therapy: a proton magnetic resonance spectroscopy study

Abstract We present a 58-year-old male chronic post-stroke central pain patient, whose pain resulted from left thalamic hemorrhage, and whose pain had failed to respond to standard pain treatment, but was resolved by electroconvulsive therapy (ECT). To investigate the potential role of neural function in ECT's analgesic effect, the patient underwent a proton magnetic resonance spectroscopy (1H-MRS) on a 2 × 2 × 2 cm voxel in the thalamus bilaterally before and after a course of unilateral ECT.The N-acetylaspartate-to-creatine (NAA/Cr) ratio, which reflects neural function, was calculated on the voxel of the thalamus. Before ECT, the left to right thalamus NAA/Cr ratio was 62.3%. The NAA/Cr ratio of the left thalamus increased 32.0% after ECT,compared to the ratio before ECT.The results from the 1H-MRS suggest that improvement of neural dysfunction in the thalamus may be related to the analgesic efficacy of ECT.

Chronic pain with beneficial response to electroconvulsive therapy and regional cerebral blood flow changes assessed by single photon emission computed tomography

Background: Recent neuroimaging studies suggested that chronic neuropathic pain may be largely sustained by a complex neuronal network involving the thalamus. Although recent studies have demonstrated the efficacy of electroconvulsive therapy (ECT) in the treatment of a variety of types of chronic neuropathic pain, the effects of ECT on regional cerebral blood flow (rCBF) have not been studied. Objectives and Methods: We present a 50-year-old female postsurgical chronic pain patient whose pain had failed to respond to standard pain treatment, but was resolved by ECT. To investigate the potential role of rCBF in ECT's analgesic effect, we measured significant changes in the rCBF in the thalamus before and after a course of bilateral ECT using technetium-99m ethyl cysteinate dimer (99mTc-ECD) single photon emission computed tomography (SPECT). Results: 99mTc-ECD SPECT showed a significant bilateral decrease in the thalamus on the side of the pain, and this decreased rCBF in the thalamus increased after ECT. Conclusions: The results from the SPECT suggest that ECT increases abnormally decreased thalamus activity in chronic neuropathic pain. Reg Anesth Pain Med 2002;27:211-213.

Chronic neuropathic pain with beneficial response to electroconvulsive therapy (ECT) and regional cerebral blood flow changes assessed by SPECT

We present two patients with type-1 complex regional pain syndrome (CRPS) and one patient with post-herpetic neuralgia (PHN) patients whose pain had failed to respond to standard pain treatment, but was resolved by electroconvulsive therapy (ECT). To investigate the potential role of regional cerebral blood flow (rCBF) involved in ECT's analgesic effect, we measured significant changes in the rCBF in the thalamus before and after a course of bilateral ECT using technetium-99m ethyl cysteinate dimer (99mTc ECD) single photon emission computed tomography (SPECT). SPECT showed significantly decreased rCBF in the thalamus which increased after ECT. The results of SPECT suggest that ECT increases abnormally decreased thalamus activity in chronic neuropathic pain. Our results from the SPECT suggest that these rCBF changes may be related to the analgesic efficacy of ECT.

Radiofrequency Cingulotomy for Intractable Cancer Pain Using Stereotaxis Guided by Magnetic Resonance Imaging

Abstract This study presents a new and simplified method of creating cingulate gyrus lesions by using stereotaxis guided by magnetic resonance imaging (MRI). Previous methods have utilized ventriculogram-guided stereotaxis requiring indirect cingulate gyrus localization and general anesthesia. With the present technique a BRW stereotactic frame was applied with the patient under local anesthesia. An MRI scan was performed using a T1 signal (TR, 600 ms; TE, 30 ms) in the coronal plane with 5-mm thick sections spaced every 6 mm. The coronal slice 24 mm posterior to the anterior tip of lateral ventricle was identified. The center of each (right and left) cingulate gyrus was identified as a target area, and appropriate coordinates were determined. Approach parameters were calculated for the right and left gyri using an azimuth of 45° and 315°, respectively, and a declination of 45°. A radiofrequency electrode was stereotactically placed so that the electrode tip was at a target point which was the center of the cingulate gyrus. A radiofrequency lesion (75°, 60 seconds) was made in each hemisphere's cingulate gyrus. Four patients with intractable terminal cancer pain have been initially treated in this manner. The lesions were well-localized on postoperative MRI scans. There have been no complications except for perilesional edema for 10 days in 1 patient (treated with longer radiofrequency settings that have subsequently been modified). Short-term pain relief in cancer patients was dramatic: morphine (intravenous 14 to 40 mg/h or oral 60 mg every 4 hours) preprocedure to oral oxycodone (1 to 2 tablets q4-6h) or oral morphine (4 to 8 mg every 4 to 6 hours) postprocedure. The use of MRI-guided stereotaxis to make cingulate gyrus lesions is an improvement that potentially allows the routine creation of these lesions as a standard cancer pain treatment. The technique is simple, uses local anesthesia, and appears to be effective and safe.