The journal of pain : official journal of the American Pain Society
-
Randomized Controlled Trial
Specific therapeutic exercise of the neck induces immediate local hypoalgesia.
This study compared the effect of 2 specific cervical flexor muscle exercise protocols on immediate pain relief in the cervical spine of people with chronic neck pain. In addition, the study evaluated whether these exercise protocols elicited any systemic effects by studying sympathetic nervous system (SNS) function and pain at a location distant from the cervical spine. Participants were randomly allocated into either a cranio-cervical flexion (CCF) coordination exercise group (n = 24) or a cervical flexion (CF) endurance exercise group (n = 24). Measures of pain and SNS function were recorded immediately before and after a single session of the exercise interventions. Pain measures included visual analogue scale (VAS) ratings of neck pain at rest and during active cervical motion and pressure pain threshold (PPT) and thermal pain threshold (TPT) recordings over the cervical spine and at a remote site on the leg. Measures of SNS function consisted of blood flow, skin conductance, skin temperature, heart rate, and blood pressure. Immediately after 1 session of exercise, there was a reasonably sized increase of 21% (P < .001, d = 0.88) and 7.3% (P = .03, d = 0.47) in PPT locally at the neck for the CCF exercise and the CF exercise, respectively. There were no changes in local neck TPT with either exercise. Pressure pain threshold and TPT at the leg and SNS did not change after exercise. Only the CCF exercise demonstrated a small improvement in VAS ratings during active movement (change on 10-cm VAS: CCF, 0.42 cm (P = .04). This study shows that specific CCF therapeutic exercise is likely to provide immediate change in mechanical hyperalgesia local to the neck with translation into perceived pain relief on movement in patients with chronic neck pain. ⋯ This study showed an immediate local mechanical hypoalgesic response to specific exercise of the cervical spine. Understanding the pain-relieving effects of exercise will assist the clinician in prescribing the most appropriate exercise protocols for patients with chronic neck pain.
-
Randomized Controlled Trial Comparative Study
Assessor status influences pain recall.
Anecdotal clinical reports suggest that patients report differing levels of pain, depending on the status within the medical hierarchy of the individual gathering the pain rating. This observation has clinical relevance, given the practice of delegating the assessment of pain to lower status clinic staff members. In this study, both pain and mood were assessed in 70 patients diagnosed with low back pain at pretreatment, immediately after epidural lumbar injection, and again 2 weeks later by phone. At the 2-week follow-up, patients were also asked to recall the postprocedural rating that they had given immediately after the injection. This rating was obtained by either the treating physician or by a research assistant who was present at the time of injection, on a randomly determined basis. Current ratings of pain and mood did not differ for either group before the epidural injection, after the epidural injection, or at the 2-week follow-up. Two-week recall of postprocedural pain did, however, differ depending on assessor status. Those called by the physician provided recalled pain ratings that closely matched the ratings provided immediately after the procedure. Those called by the research assistant provided ratings that were 86% higher (that is, worse) than their original ratings. This status-driven bias in recalled postprocedural pain reporting is discussed in the context of social demands inherent in the physician-patient relationship, with implications for assessing treatment effectiveness in clinical practice and research. ⋯ Accurate assessment of patients' pain is critical to effective pain management and treatment planning. This study found evidence of a status-based bias in which physicians elicited lower ratings of previously experienced pain associated with treatment procedures than did staff members of lower status.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Effect of early administration of the N-methyl-d-aspartate receptor antagonist amantadine on the development of postmastectomy pain syndrome: a prospective pilot study.
Postmastectomy pain syndrome (PMPS) is a neuropathic pain syndrome that might develop after breast surgery. Like many other forms of neuropathic pain, it is relatively resistant to treatment and negatively affects the quality of life. A double-blind, randomized, placebo-controlled pilot trial was conducted to study the analgesic efficacy of perioperative administration of the N-methyl-D-aspatrate (NMDA) receptor antagonist amantadine in preventing PMPS after mastectomy plus axillary lymph node dissection (ALND). In the study group, a regimen of 200 mg/day of amantadine was started 1 day before surgery and continued for 14 days, whereas the control group received a placebo. Patients were required to indicate the exact location of their pain and to record its level at 1, 3, and 6 months after surgery. Neurologic examination and Quantitative Thermal Testing (QTT) were performed 1 and 6 months after surgery. On both the neurologic examination and the QTT, all patients, regardless of the perioperative intervention (amantadine or placebo), presented evidence for nerve injury, manifested primarily by painful hypoesthesia (anesthesia dolorosa) in the axilla or inner arm. PMPS persisted for the entire duration of the study in 82% of the patients who were available for follow-up. The average intensity of the pain was moderate in both groups and tended not to decline over time. No differences between the 2 groups in any of the outcome parameters reached statistical significance. According to the results of the present pilot study, the NMDA antagonist amantadine does not prevent the development of PMPS in patients who undergo breast surgery with ALND. ⋯ Breast surgery that involves ALND seems to uniformly cause nerve injury, which cannot be prevented by the perioperative administration of 200 mg of amantadine. It is most commonly presented by painful hypoesthesia or anesthesia dolorosa in the axillary/inner arm area, which is moderate in intensity and likely to persist for at least 6 months.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Caffeine attenuates delayed-onset muscle pain and force loss following eccentric exercise.
This double-blind, placebo-controlled, repeated-measures experiment examined the effects of a 5 mg . kg(-1) body weight dose of caffeine on delayed-onset muscle pain intensity and force loss in response to 64 eccentric actions of the dominant quadriceps induced by electrical stimulation. Low caffeine-consuming college-aged females (n = 9) ingested caffeine or placebo 24 and 48 hours following electrically stimulated eccentric exercise of the quadriceps. One hour after ingestion, maximal voluntary isometric contractions (MVIC) and submaximal voluntary eccentric actions were used to determine force loss during activation of damaged quadriceps and whether caffeine attenuates muscle pain intensity. Pain intensity was measured using a 0 to 100 visual analog scale. Caffeine produced a large (12.7 raw visual analog scale [VAS] units; -48%; Cohen's d effect size = -0.88), statistically significant hypoalgesia during the MVIC (t = -2.52; df = 8; P = .036). The reduction in pain scores during submaximal voluntary eccentric movements was smaller (7.8 raw VAS units; -26%, d = -0.34), as was the increase in MVIC force (4.4%; d = 0.13). ⋯ Eccentric exercise occurs when skeletal muscles produce force while being lengthened. For example, the biceps brachii muscles act eccentrically when a cup of coffee is lowered from the mouth to a tabletop. This experiment found that caffeine (equal to approximately 2 cups of brewed coffee) could produce a large reduction in pain resulting from eccentric exercise-induced, delayed-onset muscle injury. This finding may improve the quality of life of individuals who experience skeletal muscle pain after engaging in unaccustomed, eccentrically biased exercise.
-
Randomized Controlled Trial
Efficacy and safety of OPANA ER (oxymorphone extended release) for relief of moderate to severe chronic low back pain in opioid-experienced patients: a 12-week, randomized, double-blind, placebo-controlled study.
Opioid-experienced (N = 250) patients with chronic, moderate to severe low back pain (LBP) were converted from their prestudy opioid(s) to an approximately equianalgesic dose of OPANA ER (oxymorphone extended release). Patients continued slow titration, with 56% stabilized within 1 month to a dose of OPANA ER that reduced average pain to <40 mm on a visual analog scale with good tolerability. Stabilized patients (n = 143) were randomized to placebo or their stabilized dose of OPANA ER every 12 hours for a 12-week double-blind period. Pain intensity increased significantly more for patients randomized to placebo than for patients who continued their stabilized dose of OPANA ER; the increase from baseline (at randomization) to final visit was 31.6 mm for placebo versus 8.7 mm with OPANA ER (P < .0001). During double-blind treatment, placebo patients were approximately 8-fold more likely than OPANA ER patients to discontinue because of lack of efficacy (P < .001). Discontinuations as a result of adverse events were similar between groups, 10% with placebo and 11% with OPANA ER. Opioid-related adverse events included constipation (6%), somnolence (3%), and nausea (3%). Fifty-seven percent of opioid-experienced patients with chronic, moderate to severe LBP achieved a stable dose of OPANA ER that was efficacious and generally well-tolerated for up to 12 weeks. ⋯ In a 12-week, double-blind, randomized, placebo-controlled trial in opioid-experienced patients with chronic, moderate to severe LBP, OPANA ER provided efficacious, long-term analgesia and was generally well-tolerated. OPANA ER may provide clinicians with a new treatment option for patients experiencing suboptimal analgesic responses or poor tolerability with other opioids.