Comparison between acupuncture therapy and gabapentin for chronic pain: a pilot study.

BACKGROUND: We examined whether the effect of true electroacupuncture on pain and functionality in chronic pain participants can be differentiated from that of medication (gabapentin) by analyzing quantitative sensory testing (QST). METHODS: We recruited chronic back and neck pain participants who received six sessions (twice weekly) of true electroacupuncture versus sham electroacupuncture or 3 weeks of gabapentin versus placebo treatment. QST profiles, pain scores, and functionality profile were obtained at baseline (visit 1) and after three sessions (visit 4) or six sessions (visit 7) of acupuncture or 3 weeks of gabapentin or placebo. RESULTS: A total of 50 participants were analyzed. We found no differences in QST profile changes (p = 0.892), pain reduction (p = 0.222), or functionality (p = 0.254) between the four groups. A major limitation of this pilot study was the limited number of study participants in each group. CONCLUSION: This pilot study suggests that a large-scale clinical study with an adequate sample size would be warranted to compare acupuncture and medication therapy for chronic pain management. TRIAL REGISTRATION NUMBER: NCT01678586 (ClinicalTrials.gov).

A randomized trial to assess the immediate impact of acupuncture on quantitative sensory testing, pain, and functional status.

In this randomized clinical trial, we examined whether the effect of true acupuncture can be differentiated from sham acupuncture (pain and functionality) by analyzing quantitative sensory testing (QST) profiles in chronic pain participants. We recruited 254 healthy or chronic back and neck pain participants. Healthy subjects were included to control for a possible effect of acupuncture on baseline QST changes. Study participants received 6 sessions (twice weekly) of true acupuncture, sham acupuncture, or no acupuncture treatment (routine care). Quantitative sensory testing profiles, pain scores, and functionality profile were obtained at baseline (visit 1) and after 3 (visit 4) or 6 sessions (visit 7). A total of 204 participants were analyzed. We found no QST profile changes among 3 groups (P = 0.533 and P = 0.549, likelihood ratio tests) in either healthy or chronic pain participants. In chronic back and neck pain participants, true acupuncture reduced pain (visit 4: difference in mean [DIM] = -0.8, 95% confidence interval [CI]: -1.4 to -0.1, adjusted P = 0.168; visit 7: DIM = -1.0, 95% CI: -1.7 to -0.3, adjusted P = 0.021) and improved functional status including physical functioning (DIM = 14.21, 95% CI: 5.84-22.58, adjusted P = 0.003) and energy/fatigue (DIM = 12.28, 95% CI: 3.46-21.11, adjusted P = 0.021) as compared to routine care. Our results indicate that QST was not helpful to differentiate between true acupuncture and sham acupuncture (primary outcome) in this study, although true acupuncture reduced pain and improved functionality (secondary outcomes) when compared with routine care.

Ultrasmall Superparamagnetic Iron Oxide Imaging Identifies Tissue and Nerve Inflammation in Pain Conditions.

Objective: Correlation between radiologic structural abnormalities and clinical symptoms in low back pain patients is poor. There is an unmet clinical need to image inflammation in pain conditions to aid diagnosis and guide treatment. Ferumoxytol, an ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle, is clinically used to treat iron deficiency anemia and showed promise in imaging tissue inflammation in human. We explored whether ferumoxytol can be used to identify tissue and nerve inflammation in pain conditions in animals and humans. Methods: Complete Freud's adjuvant (CFA) or saline was injected into mice hind paws to establish an inflammatory pain model. Ferumoxytol (20 mg/kg) was injected intravenously. Magnetic resonance imaging (MRI) was performed prior to injection and 72 hours postinjection. The changes in the transverse relaxation time (T2) before and after ferumoxytol injection were compared between mice that received CFA vs saline injection. In the human study, we administered ferumoxytol (4 mg/kg) to a human subject with clinical symptoms of lumbar radiculopathy and compared the patient with a healthy subject. Results: Mice that received CFA exhibited tissue inflammation and pain behaviors. The changes in T2 before and after ferumoxytol injection were significantly higher in mice that received CFA vs saline (20.8 ± 3.6 vs 2.2 ± 2.5, P = 0.005). In the human study, ferumoxytol-enhanced MRI identified the nerve root corresponding to the patient's symptoms, but the nerve root was not impinged by structural abnormalities, suggesting the potential superiority of this approach over conventional structural imaging techniques. Conclusions: Ferumoxytol-enhanced MRI can identify tissue and nerve inflammation and may provide a promising diagnostic tool in assessing pain conditions in humans.

Microglia as a Surrogate Biosensor to Determine Nanoparticle Neurotoxicity.

Nanoparticles found in air pollutants can alter neurotransmitter profiles, increase neuroinflammation, and alter brain function. Therefore, the assay described here will aid in elucidating the role of microglia in neuroinflammation and neurodegenerative diseases. The use of microglia, resident immune cells of the brain, as a surrogate biosensor provides novel insight into how inflammatory responses mediate neuronal insults. Here, we utilize an immortalized murine microglial cell line, designated BV2, and describe a method for nanoparticle exposure using silver nanoparticles (AgNPs) as a standard. We describe how to expose microglia to nanoparticles, how to remove nanoparticles from supernatant, and how to use supernatant from activated microglia to determine toxicity, using hypothalamic cell survival as a measure. Following AgNP exposure, BV2 microglial activation was validated using a tumor necrosis factor alpha (TNF-α) enzyme linked immunosorbent assay (ELISA). The supernatant was filtered to remove the AgNP and to allow cytokines and other secreted factors to remain in the conditioned media. Hypothalamic cells were then exposed to supernatant from AgNP activated microglia and survival of neurons was determined using a resazurin-based fluorescent assay. This technique is useful for utilizing microglia as a surrogate biomarker of neuroinflammation and determining the effect of neuroinflammation on other cell types.

The predictive value of sympathetic block for the success of spinal cord stimulation.

OBJECTIVE: The purpose of this study was to assess the predictive value of response to sympathetic blockade (SB) on the success rate of spinal cord stimulation (SCS) in patients with complex regional pain syndrome. METHODS: We performed a retrospective study on 23 patients with complex regional pain syndrome who underwent both SB and subsequent SCS trials in the past 3 years at the Massachusetts General Hospital Pain Center, Boston, MA, and Walter Reed Army Medical Center, Washington, DC. Fifteen of these patients underwent permanent placement of an SCS device, and pain relief at 1- and 9-month follow-up was recorded. RESULTS: Among the 23 patients included in the study, those having transient pain relief with SB were more likely to have a positive SCS trial: all 13 with positive SB had good pain relief during the trial, compared with only 3 of the 10 with negative SB (100% versus 30%, P < 0.001). Among the 10 patients with negative SB, 7 noted poor pain relief during the trial despite adequate coverage, and they did not undergo placement of a permanent device. Among the patients who underwent permanent placement of an SCS device, those who received good pain relief with SB were more likely to have greater than 50% pain relief at 1-month follow-up (100% versus 33%, P = 0.029) and 9-month follow-up (87.5% versus 33.3%, P = 0.15). CONCLUSION: We conclude that patients with good response to SB before SCS are more likely to have a positive response during their SCS trial and long-term pain relief after placement of permanent SCS device.

Complex regional pain syndrome type I after myocardial infarction treated with spinal cord stimulation.

OBJECTIVE: A rare case of Complex Regional Pain Syndrome (CRPS) type I after myocardial infarction (MI) and significant comorbid illness with few treatment options for pain control was successfully managed with the placement of a spinal cord stimulator (SCS). CASE REPORT: A 44-year-old man presented with left upper extremity burning pain after MI. His past medical history included insulin-dependent diabetes mellitus, oxygen-dependent idiopathic pulmonary fibrosis, and recent coronary revascularization surgery. His pain was presumed to be related to his MI and a clinical diagnosis of CRPS type I (or reflex sympathetic dystrophy) was made. Facing limited medical and less invasive options for his pain relief, he underwent a spinal cord stimulation trial with excellent response. He had more than 70% pain relief from the spinal cord stimulation at the last follow-up, 2 years later. CONCLUSION: CRPS type I after MI can be difficult to treat because of other comorbid illnesses. SCS can be a safe and effective mode of therapy for patients facing limited treatment options.