TL;DR: It is concluded that any single VAS score in the immediate postoperative period should be considered to have an imprecision of +/- 20 mm, and the visual analog scale was developed for assessing chronic pain but is often used in studies of postoperative pain.
Abstract: The visual analog scale (VAS) has been used to assess the efficacy of pain management regimens in patients with acute postoperative pain, but its usefulness has not been confirmed in postoperative pain studies. We studied 60 subjects in the immediate postoperative period. The specific data collected were: VAS scores versus an 11-point numeric pain scale; repeatability in VAS scores over a short time interval; and change in VAS scores from one assessment period to the next versus a verbal report of change in pain. The correlation coefficients for VAS scores with the 11-point pain scale were 0.94, 0.91, and 0.95. The repeatability coefficients were 17.6, 23.0, and 13.5 mm. Of the 56 patients who completed all three assessments, only 16 (29%) had repeatability within 5 mm on all three. Some of the changes in VAS scores between assessments were in the direction opposite the verbally reported changes in pain (31%); however, most (92%) were within 20 mm. There was no correlation between the level of sedation, previous pain experience, anxiety, or anticipated pain with consistency in VAS scores. We conclude that any single VAS score in the immediate postoperative period should be considered to have an imprecision of +/- 20 mm. Implications The visual analog scale was developed for assessing chronic pain but is often used in studies of postoperative pain. This study finds that the visual analog scale correlates well with a verbal 11-point scale but that any individual determination has an imprecision of +/- 20 mm.
TL;DR: Patients undergoing general, trauma, or oral and maxillofacial surgery were studied and a treatment threshold of average pain of NRS≥4 was considered to identify patients with pain of moderate-to-severe intensity.
Abstract: Background Cut-off points (CPs) of the numeric rating scale (NRS 0–10) are regularly used in postoperative pain treatment. However, there is insufficient evidence to identify the optimal CP between mild and moderate pain. Methods A total of 435 patients undergoing general, trauma, or oral and maxillofacial surgery were studied. To determine the optimal CP for pain treatment, four approaches were used: first, patients estimated their tolerable postoperative pain intensity before operation; secondly, 24 h after surgery, they indicated if they would have preferred to receive more analgesics; thirdly, satisfaction with pain treatment was analysed, and fourthly, multivariate analysis was used to calculate the optimal CP for pain intensities in relation to pain-related interference with movement, breathing, sleep, and mood. Results The estimated tolerable postoperative pain before operation was median (range) NRS 4.0 (0–10). Patients who would have liked more analgesics reported significantly higher average pain since surgery [median NRS 5.0 (0–9)] compared with those without this request [NRS 3.0 (0–8)]. Patients satisfied with pain treatment reported an average pain intensity of median NRS 3.0 (0–8) compared with less satisfied patients with NRS 5.0 (2–9). Analysis of average postoperative pain in relation to pain-related interference with mood and activity indicated pain categories of NRS 0–2, mild; 3–4, moderate; and 5–10, severe pain. Conclusions Three of the four methods identified a treatment threshold of average pain of NRS≥4. This was considered to identify patients with pain of moderate-to-severe intensity. This cut-off was indentified as the tolerable pain threshold.
TL;DR: A systematic review of studies of the effectiveness and harms of spinal manipulative therapy (SMT) for acute (≤6 weeks) low back pain is presented in this paper. But the authors did not identify any serious adverse events such as increased pain, muscle stiffness and headache.
Abstract: Importance Acute low back pain is common and spinal manipulative therapy (SMT) is a treatment option. Randomized clinical trials (RCTs) and meta-analyses have reported different conclusions about the effectiveness of SMT. Objective To systematically review studies of the effectiveness and harms of SMT for acute (≤6 weeks) low back pain. Data Sources Search of MEDLINE, Cochrane Database of Systematic Reviews, EMBASE, and Current Nursing and Allied Health Literature from January 1, 2011, through February 6, 2017, as well as identified systematic reviews and RCTs, for RCTs of adults with low back pain treated in ambulatory settings with SMT compared with sham or alternative treatments, and that measured pain or function outcomes for up to 6 weeks. Observational studies were included to assess harms. Data Extraction and Synthesis Data extraction was done in duplicate. Study quality was assessed using the Cochrane Back and Neck (CBN) Risk of Bias tool. This tool has 11 items in the following domains: randomization, concealment, baseline differences, blinding (patient), blinding (care provider [care provider is a specific quality metric used by the CBN Risk of Bias tool]), blinding (outcome), co-interventions, compliance, dropouts, timing, and intention to treat. Prior research has shown the CBN Risk of Bias tool identifies studies at an increased risk of bias using a threshold of 5 or 6 as a summary score. The evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. Main Outcomes and Measures Pain (measured by either the 100-mm visual analog scale, 11-point numeric rating scale, or other numeric pain scale), function (measured by the 24-point Roland Morris Disability Questionnaire or Oswestry Disability Index [range, 0-100]), or any harms measured within 6 weeks. Findings Of 26 eligible RCTs identified, 15 RCTs (1699 patients) provided moderate-quality evidence that SMT has a statistically significant association with improvements in pain (pooled mean improvement in the 100-mm visual analog pain scale, −9.95 [95% CI, −15.6 to −4.3]). Twelve RCTs (1381 patients) produced moderate-quality evidence that SMT has a statistically significant association with improvements in function (pooled mean effect size, −0.39 [95% CI, −0.71 to −0.07]). Heterogeneity was not explained by type of clinician performing SMT, type of manipulation, study quality, or whether SMT was given alone or as part of a package of therapies. No RCT reported any serious adverse event. Minor transient adverse events such as increased pain, muscle stiffness, and headache were reported 50% to 67% of the time in large case series of patients treated with SMT. Conclusions and Relevance Among patients with acute low back pain, spinal manipulative therapy was associated with modest improvements in pain and function at up to 6 weeks, with transient minor musculoskeletal harms. However, heterogeneity in study results was large.
TL;DR: Individuals with high catastrophizing levels demonstrated higher pain intensities and lower effects of DNIC indicating that catastrophize might have a significant impact on pain perception via an association with pain modulation.
Abstract: The multidimensional experience of pain is thought to be partially influenced by the pain modulation system as well as by individual psychological components. Recent studies demonstrated possible common neural network mediating both domains. The present study examined the relationships between pain perception, pain modulation, and catastrophizing in healthy subjects. Forty-eight participants (29 females and 19 males) completed the pain catastrophizing scale (PCS) and underwent psychophysical tests in order to evaluate the modulation of pain, using the diffuse noxious inhibitory control (DNIC) paradigm. Contact heat pain (47.0°C applied for 1 min), which was used as the “test” stimulation, was applied before and after a physical effort that induces pain (repeated squeezing of a hand grip device), which was used as a “conditioning” stimulus. Numeric pain scale intensities (NPS, 0–10) were evaluated four times during each of two separate consecutive runs of heat stimulation. Results showed a significant positive correlation of PCS with heat pain (r = 0.48, p < 0.0005) and with muscle pain (r = 0.31, p = 0.03). In addition, significant negative correlations were found between PCS and DNIC effect (r = −0.34, p = 0.02). Moreover, once catastrophizing was entered into the regression analysis, the previously significant effect of gender was no longer found. In conclusion, individuals with high catastrophizing levels demonstrated higher pain intensities and lower effects of DNIC indicating that catastrophizing might have a significant impact on pain perception via an association with pain modulation.