Pain Sensitivity In Patients Research Articles

Efficacy of Home-Based Transcranial Direct Current Stimulation on Experimental Pain Sensitivity in Older Adults with Knee Osteoarthritis: A Randomized, Sham-Controlled Clinical Trial.

Although transcranial direct current stimulation (tDCS) is encouraging regarding clinical pain intensity for individuals with knee osteoarthritis, very few studies have explored its impact on experimental pain sensitivity, which may hinder our understanding of underlying therapeutic mechanisms. The purpose of this study was to assess the efficacy of 15 home-based tDCS sessions on experimental pain sensitivity and explore its relationships with clinical pain intensity. We randomly assigned 120 participants to active tDCS (n = 60) and sham tDCS (n = 60). Quantitative sensory testing (QST) was used, including heat pain threshold and tolerance, pressure pain threshold, and conditioned pain modulation. Patients in the active tDCS group exhibited reduced experimental pain sensitivity as reflected by all QST measures at the end of treatment. Furthermore, correlations were observed between changes in clinical pain intensity and experimental pain sensitivity. These findings warrant further studies on tDCS and experimental pain sensitivity in patients with knee osteoarthritis and exploring the magnitude and sustainability of effects on a longer term.

Tendinopathies and Pain Sensitisation: A Meta-Analysis with Meta-Regression.

The presence of pain sensitisation has been documented and reported as being a possible cause of treatment failure and pain chronicity in several musculoskeletal conditions, such as tendinopathies. The aim of the present study is to analyse existing evidence on pain sensitisation in tendinopathies comparing the local and distant pain thresholds of healthy and affected subjects with distinct analysis for different tendinopathies. PubMed, Cochrane Central Register, Scopus, and Web Of Science were systematically searched after registration on PROSPERO (CRD42020164124). Level I to level IV studies evaluating the presence of pain sensitisation in patients with symptomatic tendinopathies, documented through a validated method, were included. A meta-analysis was performed to compare local, contralateral, and distant pain thresholds between patients and healthy controls with sub-analyses for different tendinopathies. Meta-regressions were conducted to evaluate the influence of age, activity level, and duration of symptoms on results. Thirty-four studies out of 2868 were included. The overall meta-analysis of local pressure pain thresholds (PPT) documented an increased sensitivity in affected subjects (p < 0.001). The analyses on contralateral PPTs (p < 0.001) and distant PPTs (p = 0.009) documented increased sensitivity in the affected group. The results of the sub-analyses on different tendinopathies were conflicting, except for those on lateral epicondylalgia. Patients’ activity level (p = 0.02) and age (p = 0.05) significantly influenced local PPT results. Tendinopathies are characterized by pain sensitisation, but, while features of both central and peripheral sensitisation can be constantly detected in lateral epicondylalgia, results on other tendinopathies were more conflicting. Patients’ characteristics are possible confounders that should be taken into account when addressing pain sensitisation.

Pain Tolerance in Chronic Pain Patients Seems to be More Associated with Physical Activity than with Depression and Anxiety

ObjectiveTo explore the associations between habitual self-reported physical activity, pain sensitivity and patient-reported outcomes (including pain intensity) in patients with chronic pain.DesignCross-sectional, experimental study.SubjectsPatients (n = 78), age range 18–65 years, with different chronic pain conditions (> 3 months) were compared with age- and sex-matched healthy controls (n = 98).MethodsMultivariate correlations between self-reported physical activity, pressure pain sensitivity, and patient-reported outcome measures were assessed.ResultsLower perceived health status (p < 0.001, Cohen’s d = 2.34), higher levels of depression (p < 0.001, Cohen’s d = 1.77), and lower pain tolerance threshold (p < 0.001, Cohen’s d = 1.66) were the most prominent variables discriminating patients from controls. In patients, bivariate and multivariate analyses showed that higher pressure pain tolerance was associated with male sex, lower pain intensity and fewer painful regions, higher self-efficacy and more self-reported physical activity, but not with lower levels of anxiety and depression.ConclusionPain tolerance thresholds, as well as degree of depression and perceived health status discriminated between patients and controls, and there was an association between pain tolerance thresholds and level of self-reported physical activity in patients. This study highlights the importance of further research into how increased physical activity may improve pain sensitivity in patients with chronic pain.LAY ABSTRACTPatients with chronic pain and healthy controls were included in this study of the relationships between self-reported physical activity, measurements of sensitivity to pressure pain, and questionnaire data. Pressure pain sensitivity was one of the most important factors discriminating between patients and controls, and there was a significant correlation between pain tolerance threshold and level of self-reported physical activity in patients (i.e. the lower pain thresholds the less physical activity). These results are relevant, as there are only a few previous studies examining the relationship between physical activity in patients with chronic pain and their sensitivity to pressure pain. More research is needed to explore how daily physical activity may improve chronic pain by, for example, increasing patient’s tolerance to pain.

Intra-rater and inter-rater reliability of pressure pain threshold assessment in stroke patients.

As pain is a common symptom following a stroke, pressure pain threshold (PPT) assessment can be used to evaluate pain status or pain sensitivity of patients. However, the reliability of PPT test in stroke patients is still unknown. To examine the intra- and inter-rater reliability of PPT measurements in poststroke survivors and explore their factors. An observational study. The setting of the study is a rehabilitation hospital. The population of the study was represented by a total of 54 patients after stroke. The study included 16 measured points on the affected and unaffected sides. PPT was assessed by two raters in turn. Intra- and inter-rater reliability was evaluated by intraclass correlation coefficients (ICC). All intra-rater (ICC=0.84-0.97) and inter-rater (ICC=0.83-0.95) reliability for PPT assessment were good or excellent in stroke patients. Of the 16 points, 12 showed higher intra-rater ICC values than inter-rater, whereas no evident difference was observed between the affected and unaffected sides. Furthermore, patients who were male, ischemic, or with higher motor function generally performed higher ICC values than those who were female (24 out of 32 results), hemorrhagic (28 out of 32 results), or mobility dysfunction (26 out of 32 results), respectively. PPT assessment with good or excellent reliability can be used in stroke patients. Neither of the two sides (affected or unaffected) affects PPT reliability, and intra-rater reliability is better than inter-rater reliability. In addition, gender, stroke type, and motor function can affect the reliability of measuring mechanical pain threshold in poststroke survivors. The pressure algometer can be used as a reliable and portable tool to assess the mechanical pain tolerance and sensory function in stroke patients in clinics.

High Prevalence of Pain Sensitization in Knee Osteoarthritis: A Meta-Analysis with Meta-Regression.

ObjectiveThe aim of this meta-analysis was to study the evidence on pain sensitization in knee osteoarthritis (OA), providing a quantitative synthesis of its prevalence and impact. Factors associated with pain sensitization were also investigated.MethodsMeta-analysis; PubMed (MEDLINE), Cochrane Central Register (CENTRAL), and Web of Science were searched on February 2021. Level I to level IV studies evaluating the presence of pain sensitization in patients with symptomatic knee OA, documented through a validated method (questionnaires or quantitative sensory testing), were included. The primary outcome was the prevalence of pain sensitization. Factors influencing the prevalence were also evaluated, as well as differences in terms of pain thresholds between knee OA patients and healthy controls.ResultsFifty-three articles including 7,117 patients were included. The meta-analysis of proportion documented a prevalence of pain sensitization of 20% (95% confidence interval [CI] = 16%-26%) with a significant heterogeneity of results (I2 = 89%, P < 0.001). The diagnostic tool used was the main factor influencing the documented prevalence of pain sensitization (P = 0.01). Knee OA patients presented higher pain sensitivity compared with healthy controls, both in terms of local pressure pain threshold (standardized mean difference [SMD] = −1.00, 95% CI = −1.67 to −0.32, P = 0.007) and distant pressure pain threshold (SMD = −0.54, 95% CI = −0.76 to −0.31, P < 0.001).ConclusionsKnee OA pain presents features that are consistent with a significant degree of pain sensitization. There is a high heterogeneity in the reported results, mainly based on the diagnostic tool used. The identification of the best methods to detect pain sensitization is warranted to correctly evaluate and manage symptoms of patients affected by knee OA.Registration:PROSPERO CRD42019123347.

Pain Tolerance Self-Assessment vs Objective Pressure Sensitivity: Do Patients Accurately Estimate Their Own Pain Tolerance?

Category:Basic Sciences/Biologics; OtherIntroduction/Purpose:Effective pain treatment remains elusive in the orthopedic foot and ankle practice as evidenced by the variable experience of pain, post-operative or otherwise. Intrinsic pain tolerance is likely contributing to this variability in the patient's experience of pain. Pressure dolorimetry is a validated, objective measure to assess pressure sensitivity and is correlated with pain tolerance. No previous study in the orthopedic foot and ankle literature has attempted to correlate objective versus subjective pain tolerance. General mental health is associated with central pain sensitization and may also affect pain tolerance. Our hypothesis was that subjective self-assessment of pain tolerance would be correlated with objective dolorimetry. We hypothesized that mental patient-reported outcome scores would also be correlated to objective pain tolerance.Methods:Prospectively-collected patient-reported outcome scores (PROMIS), dolorimetry measurements, and survey data of subjective reported pain tolerance were collected pre-operatively on 50 consecutive patients by two surgeons in an urban orthopedic foot and ankle practice. Patients were included if they had normal sensation on the plantar foot and no prior surgery or plantar heel source of pain. Each patient underwent objective measurement of their ability to withstand pressure applied to the plantar heel causing 5/10 pain using a hand-held dolorimeter with digital pressure measurement display. Each patient was administered a preoperative battery of PROMIS physical function (PF), pain interference (PI), and mood/depression (M) instruments, and a separate survey where they scaled their subjective tolerance to pain and discomfort. Statistical analysis was performed utilizing students t-test for continuous variables. Correlations were evaluated with Pearson's R coefficient. Data are reported as means (+/- standard deviation) unless otherwise noted.Results:50 patients received hand-held dolorimetry measurements, completed the pain tolerance survey, and completed PROMIS measures. Dolorimetry data from the plantar heel was normally distributed with mean force 24 N/cm2 (+/-10) to reflect a 5/10 pain experienced by the patient. Patients were shown to estimate their pain threshold with mean subjective pain threshold 6.8/10 (+/-2) regardless of objective pain data or PROMIS scores. The mean PROMIS scores of the sample were PF (41+/-8), PI (60+/-7), and M (49+/-9) reflecting a sample with decreased physical function and increased pain which could be expected in an outpatient foot and ankle clinic. There was a negative correlation of R=(-0.432) regarding PROMIS-M with dolorimetry objective pain tolerance which was statistically significant (p<-0.05). Patients had more features of depression/anxiety (PROMIS-M score >60) had a statistically significant decrease in pain threshold to 18+/-8 N/cm2 compared to 30 +/- 9 N/cm2 for those who were less depressed (p<0.01)).Conclusion:Subjective self assessment of pain tolerance is not well correlated to objective pain threshold data or other markers of mental health, and should not influence medical decision-making. Features of depression on PROMIS-M are associated with an objectively lower pain threshold which is in agreement with prior findings of central pain sensitization in patients with depression and anxiety in other studies. Future work is required to correlate dolorimetry data with post-operative medication utilization, and patient-reported outcome measures after surgery.

Patients with symptomatic permanent atrial fibrillation show quantitative signs of pain sensitisation

Abstract Background/Introduction Most patients with atrial fibrillation (AF) report symptoms, while around one-third are asymptomatic. We hypothesized that sensory processing, in particular pain, differs in patients with symptomatic and asymptomatic AF. Purpose To assess differences in pain sensitisation in patients with symptomatic and asymptomatic AF. Methods Thirty individuals with permanent AF (15 symptomatic, 15 asymptomatic) completed the AF6 and SF-36 questionnaires and underwent quantitative pain sensitisation testing using pressure algometry at the sternum (referred pain area) and the tibialis anterior muscle (generalized pain area). The primary objective was to assess differences in pressure pain thresholds (PPT), temporal summation of pain (TSP), and conditioned pain modulation (CPM) in the two groups. The secondary objective was to determine association of demographic and clinical parameters to quantitative measures of pain sensitisation. Results The symptomatic group had lower PPTs at both tibialis (p=0.004) and sternum (p=0.01), as well as impaired CPM (p=0.025) and facilitated TSP (p=0.008) at the tibialis but not sternum, compared to the asymptomatic group. The AF6 sum score was negatively correlated to PPT on both tibialis (r=−0.50, p=0.005) and sternum (r=−0.42, p=0.02) and positively correlated to TSP of both tibialis (r=0.57, p=0.001) and sternum (r=0.45, p=0.01), but not to CPM. The physical component summary score was positively correlated to the PPT on both tibialis (r=0.52, p=0.003) and sternum (r=0.40, p=0.03) and negatively to TSP on the tibialis (r=−0.53, p=0.003) but not sternum. Conclusions Patients with symptomatic AF exhibit lower pain tolerance than patients with asymptomatic AF, as well as impaired pain inhibitory control and facilitated summation of pain, indicating that pain sensitisation may be of importance in symptomatic AF. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, Örebro University, Sweden PPTs tibialis anterior musclePPTs sternum

Effect of the duration of chronic low back pain on pain sensitivity of patients undergoing lumbar fusion surgery

Background: chronic low back pain is a serious social problem. In recent years, patients who choose lumbar fusion surgery due to chronic low back pain has been increasing. Pre-existing chronic pain has been associated with severe postoperative pain. In this study, we have sought to prospectively analyze the association between the duration of chronic low back pain and pain sensitivity after lumbar fusion surgery. Methods: 400 patients who underwent lumbar fusion surgery were divided into three groups based on the duration of chronic pain. During the first postoperative day, the maximum pain scores of each patient day and night, the pain scores at the day of discharge, the consumption of postoperative analgesics and the length of hospital stay were recorded. Results: of 400 patients recruited, 369 patients completed the experiment. There was no significant difference in gender, age, height, weight, pre-operative pain at rest, and operation time in the three groups. During the day, the pain sensitivity of the three groups were 1.71 ± 0.66, 2.40 ± 0.74, 2.90 ± 0.80. During the night, the pain sensitivity of the three groups were 3.45 ± 0.81, 4.31 ± 1.06, 4.86 ± 1.05. At the day of discharge, the pain sensitivity of three groups were 1.26 ± 0.46, 1.47 ± 0.58, 1.96 ± 0.64. There were significant differences in pain sensitivity among the three groups during the day and night on the first postoperative day and at the day of discharge (p &lt; 0.05). The length of hospital stay (7.31 ± 1.36 days, 8.82 ± 1.48 days, 9.60 ± 1.61 days) and analgesic consumption (25.04 ± 36.56 mg, 33.52 ± 24.04 mg, 45.15 ± 24.89 mg, morphine equivalent) were also significant differences (p &lt; 0.05). Conclusion: we found the duration of chronic low back pain before lumbar fusion surgery affects patient’ postoperative pain sensitivity, consumption of analgesic drugs and hospital stay. The longer the preoperative chronic pain lasts, the higher the postoperative VAS score is, the more analgesic drugs were consumed, and the longer hospital stay is.

Pain Sensitivity in Schizophrenia Spectrum Disorders: A Narrative Review of Recent Work

Many patients with schizophrenia seem relatively immune to physical pain while others complain of constant pain. This may result from disturbances or alterations of the sensory threshold for pain in populations with psychosis, a possibility for which there is some preliminary evidence. The inconsistency in pain perception may, in part, be explained by the treatments patients receive, but treatment-naïve patients also exhibit differences in response to pain. This suggests that decreased pain sensitivity may represent a specific psychosis endophenotype. Thus far, few experimental studies have investigated sensory thresholds, pain modalities, or other factors contributing to the perception or expression of physical pain in psychosis. A digital search for information on this topic was conducted in PubMed and Google Scholar. The result is a non-systematic, narrative review focusing on recent clinical and experimental findings of pain sensitivity in patients with psychosis. Importantly, physical and mental pain are closely connected constructs that may be difficult to differentiate. Our hope is that the review provides some clarity to the field in the specific context of schizophrenia.

Predicted Versus Non-Predicted Opioid Administration Using Preoperative Pain Sensitivity in Patients Undergoing Gynecological Surgery: A Randomized-Controlled Trial.

Individualized administration of opioids based on preoperative pain sensitivity may improve postoperative pain profiles. This study aimed to examine whether a predicted administration of opioids could reduce opioid-related adverse effects after gynecological surgery. Patients were randomized to the predicted group or control group. Participants received a preoperative sensory test to measure pressure pain thresholds. Patients were treated with a higher or lower (15 or 10 μg/mL) dose of fentanyl via intravenous patient-controlled analgesia. The opioid dose was determined according to pain sensitivity in the predicted group, while it was determined regardless of pain sensitivity in the control group. The primary outcome was the incidence of nausea over the first 48 h postoperative period. Secondary outcomes included postoperative pain scores and opioid requirements. There was no difference in the incidence of nausea (40.0% vs. 52.5% in predicted and control groups, respectively; p = 0.191) and postoperative pain scores (3.3 vs. 3.5 in predicted and control groups, respectively; p = 0.691). However, opioid consumptions were lower in the predicted group compared to the control group (median 406.0 vs. 526.5 μg; p = 0.042). This study showed that offering a predicted dose of opioids according to pain sensitivity did not affect the incidence of nausea and pain scores.

Capsaicin-induced pain sensitivity in short tear break-up time dry eye

PurposeTo evaluate transient receptor potential vanilloid 1 (TRPV1)-mediated pain sensitivity in patients with short tear break-up time (TBUT) dry eye (DE) by using the capsaicin stimulus test. MethodsThis prospective cross-sectional comparative study included 22 eyes of 22 patients with short TBUT DE and 11 eyes of 11 non-DE control subjects. Patients were divided into two groups based on response to standard DE treatments: 10 non-responders (intractable DE) and 12 responders (responsive DE). Mechanical touch (M-touch) and mechanical pain (M-pain) were measured using a Cochet-Bonnet esthesiometer. Capsaicin-induced pain (C-pain) and C-pain duration (C-pain DT) were measured using a capsaicin stimulus test. Psychological distress was also assessed. ResultsM-touch sensitivity was similar among all three groups. M-pain sensitivity was higher in the responsive DE group than in the intractable DE and control groups (P < .001). C-pain sensitivity was lower (P < .001) in the intractable DE group than in the responsive DE and control groups, and C-pain DT was shorter (P = .006) in the intractable DE group than in the responsive DE group. Psychological distress was higher in the intractable DE group than in the control group (P < .001). ConclusionsPatients with intractable short TBUT DE were less sensitive to the effects of capsaicin than patients with responsive short TBUT DE and controls. Altered neural activation may contribute to the development of DE symptoms in the short TBUT DE subjects. The capsaicin stimulus test may be used to better understand pain sensitivity in short TBUT DE patients.

The effect of vibration therapy on neck myofascial trigger points: A randomized controlled pilot study

BackgroundThe purpose of this study was to evaluate the effect of low-frequency self-administered vibration therapy into myofascial trigger points in the upper trapezius and levator scapulae on patients with chronic non-specific neck pain. MethodsTwenty-eight patients with chronic non-specific neck pain were randomly assigned into a vibration group, receiving 10 self-applied sessions of vibration therapy in the upper trapezius and levator scapulae trigger points; or a control group, receiving no intervention. Self-reported neck pain and disability (Neck Disability Index) and pressure pain threshold were assessed at baseline and after the first, fifth and 10th treatment sessions. FindingsSignificant differences were found in the vibration group when compared to the control group after the treatment period: the vibration group reached lower Neck Disability Index scores (F = 4.74, P = .033, η2 = 0.07) and greater pressure pain threshold values (F = 7.56, P = .01, η2 = 0.10) than the control group. The vibration group reported a significant reduction in Neck Disability Index scores (χ2 = 19,35, P = .00, Kendall's W = 0.28) and an increase in pressure pain threshold (χ2 = 87,10, P = .00, Kendall's W = 0.73) between the assessment times over the course of the treatment. The mean increase in pressure pain threshold in the vibration group after the 10 sessions was 8.54 N/cm2, while the mean reduction in Neck Disability Index scores was 4.53 points. InterpretationVibration therapy may be an effective intervention for reducing self-reported neck pain and disability and pressure pain sensitivity in patients with chronic non-specific neck pain. This tool could be recommended for people with non-specific neck pain.

Dynamic Pressure Pain Hypersensitivity as Assessed by Roller Pressure Algometry in Episodic Cluster Headache

A method for assessing dynamic muscle hyperalgesia (dynamic pressure algometry) has been developed and applied in tension-type and migraine headaches. To investigate differences in dynamic pressure pain assessment over the trigeminal area between men with cluster headache (CH) and headache-free controls, and the association between dynamic and static pressure pain sensitivity. A case-control study. Tertiary urban hospital. Forty men with episodic CH and 40 matched controls participated. Dynamic pressure pain sensitivity was assessed with a dynamic pressure algometry set consisting of 8 rollers with different fixed levels (500, 700, 850, 1,350, 1,550, 2,200, 3,850, and 5,300 g). Each roller was moved at a speed of 0.5 cm/sec over a diagonal line covering the temporalis muscle from an anterior to posterior direction. The dynamic pressure threshold (DPT; load level of the first painful roller) and the pain intensity perceived at the DPT level (roller-evoked pain) were assessed. Static pressure pain thresholds (PPT) were also assessed with a digital pressure algometer applied statically over the mid-muscle belly of the temporalis. Patients were assessed in a remission phase, at least 3 months from the last cluster attack, and without preventive medication. Side-to-side consistency between DPTs (r = 0.781, P < 0.001), roller-evoked pain on DPT (r = 0.586; P < 0.001), and PPTs (r = 0.874; P < 0.001) were found in men with CH. DPT was moderately, bilaterally, and side-to-side associated with PPTs (0.663 > r > 0.793, all P < 0.001). Men with CH had bilateral lower DPT and PPT and reported higher levels of roller-evoked pain (all P < 0.001) than headache-free controls. Only men with episodic CH were included. This study supports that a dynamic pressure algometry is as valid as a static pressure algometry for assessing pressure pain sensitivity in patients with CH. Assessing both dynamic and static pain sensitivity may provide new opportunities for differentiated diagnostics. Cluster headache, dynamic pressure pain, pressure pain threshold.

Effect of Manual Therapy and Therapeutic Exercise Applied to the Cervical Region on Pain and Pressure Pain Sensitivity in Patients with Temporomandibular Disorders: A Systematic Review and Meta-analysis.

To assess the effectiveness of cervical manual therapy (MT) on patients with temporomandibular disorders (TMDs) and to compare cervico-craniomandibular MT vs cervical MT. Systematic review and meta-analysis (MA). A search in PubMed, EMBASE, PEDro, and Google Scholar was conducted with an end date of February 2019. Two independent reviewers performed the data analysis, assessing the relevance of the randomized clinical trials regarding the studies' objectives. The qualitative analysis was based on classifying the results into levels of evidence according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE). Regarding cervical MT, MA included three studies and showed statistically significant differences in pain intensity reduction and an increase in masseter pressure pain thresholds (PPTs), with a large clinical effect. In addition, the results showed an increase in temporalis PPT, with a moderate clinical effect. MA included two studies on cervical MT vs cervico-craniomandibular MT interventions and showed statistically significant differences in pain intensity reduction and pain-free maximal mouth opening, with a large clinical effect. Cervical MT treatment is more effective in decreasing pain intensity than placebo MT or minimal intervention, with moderate evidence. Cervico-craniomandibular interventions achieved greater short-term reductions in pain intensity and increased pain-free MMO over cervical intervention alone in TMD and headache, with low evidence.

Pressure pain sensitivity in patients with traumatic first-time and recurrent anterior shoulder dislocation: a cross-sectional analysis.

Background and aims Traumatic anterior shoulder dislocation (ASD) is frequent in active populations and associated with a 39% higher risk of recurrent dislocation, which may cause persistent shoulder problems, pain, and impaired shoulder-related quality of life. While local and distant pressure pain sensitivity has been demonstrated in other shoulder conditions, little is known about the link between pressure pain sensitivity and ASD. The interesting aspect is whether recurrent dislocation - resulting in symptoms of longer duration - is associated with more pronounced pressure pain sensitivity, or if presence of pressure pain sensitivity may be part of the reasons why patients develop recurrent dislocation. Therefore, this study aimed at evaluating whether patients with recurrent ASD display greater pressure pain sensitivity and more painful body sites than patients with first-time ASD. Methods This was a cross-sectional analysis of baseline data from a randomized controlled trial including 34 patients with first-time ASD [82% male, mean (SD) age 26 (7) years] and 22 patients with recurrent ASD [96% male, mean (SD) age 25 (5) years]. Patients were assessed as follows: (1) assessment of local and distant pressure pain sensitivity evaluated by pressure pain thresholds (PPTs) using a handheld algometer on mm. trapezius superior, levator scapula, pectorales major, deltoideus, and tibialis anterior, (2) pain intensity at rest during the previous 24 h, (3) number of ASD, and (4) number of painful body sites on a region-divided body chart. Results The PPTs were not significantly different between first-time and recurrent ASD [mean (SD) kPa for m. trapezius superior 264 (110) vs. 261 (88), m. levator scapula 301 (157) vs. 325 (163), m. pectorales major 234 (163) vs. 269 (130), m. deltoideus 290 (166) vs. 352 (173), m. tibialis anterior 420 (202) vs. 449 (184)], two-way ANCOVA, adjusted for sex and age, F (4,263) = 0.29, p = 0.88. For both groups, the PPTs were lower at the shoulder sites than at m. tibialis anterior (difference 117-184 kPa, 95% CI range 33-267). Females had lower PPTs than males (difference 124 kPa, 95% CI 64-183). The number (SD) of painful body sites were 2.2 (1.9) for first-time ASD and 2.6 (5.4) for recurrent ASD, with no between-group differences, one-way ANCOVA, adjusted for sex and age, F (1, 52) = 0.24, p = 0.63. There was a strong correlation between PPTs at the shoulder and lower leg, r = 0.84, p < 0.01. Conclusions This study demonstrated no differences in local and distant pressure pain sensitivity or number of painful body sites between patients with first-time and recurrent ASD. Females had lower PPTs than males, and a strong correlation was found between PPTs at the shoulder and lower leg. Implications Patients with first-time and recurrent ASD seem to have similar pressure pain sensitivity, but lower PPTs compared to existing normative data, suggesting that it is relevant to evaluate the status of the pain system in these patients to prevent triggering or worsening of their symptoms. However, it remains unanswered how these changes affect the patients' ability to undergo rehabilitation, symptom response and long-term shoulder function.

Widespread Pressure Pain Sensitivity over Nerve Trunk Areas in Women with Frequent Episodic Tension-Type Headache as a Sign of Central Sensitization.

Previous studies reported the presence of widespread pressure pain sensitivity in patients with tension-type headache. However, most of the studies assessed pressure pain sensitivity over muscle tissue. Our aim was to investigate the difference in pressure pain sensitivity over musculoskeletal and nerve symptomatic and distant areas between women with frequent episodic tension-type headache (FETTH) and healthy subjects. Thirty-two women with FETTH and 32 matched healthy women participated. Pressure pain threshold (PPT) was bilaterally assessed over several nerve trunks (greater occipital, median, radial, ulnar, common peroneal, tibialis posterior) and musculoskeletal structures (temporalis muscle, C5/C6 joint, tibialis anterior) by an assessor blinded to the subject's condition. A four-week headache diary was used to collect the intensity, frequency, and duration of headache. The Hospital Anxiety and Depression Scale was used to determine anxiety and depressive levels. Analysis of covariance found lower widespread and bilateral PPTs over all nerve trunks and musculoskeletal structures in women with FETTH pain (P < 0.001). No significant effect of anxiety and depressive levels on PPTs was found (all P > 0.222). PPT over the temporalis muscle was significantly negatively correlated with headache intensity. This study found widespread pressure pain hypersensitivity over both nerve trunks and musculoskeletal structures in women with FETTH, suggesting that the presence of central altered nociceptive processing is not just restricted to musculoskeletal areas, for example, muscles, but also pain evoked from directly provoking the nerve trunks by pressure. It is also possible that nerve tissue treatment could lead to a decrease in central sensitization and headache features.

Effect of spinal manipulative therapy on mechanical pain sensitivity in patients with chronic nonspecific low back pain: a pilot randomized, controlled trial

ABSTRACTObjectives: The long-term goal of our study is to improve the understanding of the biological mechanisms associated with spinal manipulative therapy (SMT) in low back pain.Methods: This project involved a pilot randomized, blinded clinical trial (ClinicalTrials.gov registration number NCT03078114) of 3-week SMT in chronic nonspecific low back pain (CNSLBP) patients. We recruited 29 participants and randomly assigned them into either a SMT (n = 14) or sham SMT (n = 15) group. Pre- and postintervention, we quantified the effect of SMT on clinical outcomes (Numeric Pain Rating Scale and Oswestry Disability Index) and pressure pain threshold (PPT) at local (lumbar spine), regional (lower extremity), and remote (upper extremity) anatomical sites.Results: We observed a significant main effect for time signifying reduced hypersensitivity (increased PPT) at local (p = .015) and regional (p = .014) locations at 3 weeks. Furthermore, we found significant main effects of time indicating improvements in pain (p < .001) and disability (p = .02) from baseline among all participants regardless of intervention. However, no between-group differences were observed in PPT, clinical pain, or disability between the SMT and sham SMT groups over 3 weeks.Conclusions: After 3 weeks of SMT or sham SMT in CNSLBP patients, we found hypoalgesia at local and remote sites along with improved pain and low back-related disability.Level of Evidence: 1bTrial registration: ClinicalTrials.gov identifier: NCT03078114.

Quantitative assessment of nonpelvic pressure pain sensitivity in urologic chronic pelvic pain syndrome: a MAPP Research Network study.

Experimental pain sensitivity was assessed in individuals with urologic chronic pelvic pain syndrome (UCPPS) as part of the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network. A series of computer-controlled pressure stimuli were delivered to the thumbnail bed, an asymptomatic site distant from the area of UCPPS pain that is considered to be indicative of overall body pain threshold. Stimuli were rated according to a standardized magnitude estimation protocol. Pain sensitivity in participants with UCPPS was compared with healthy controls and a mixed pain group composed of individuals with other chronic overlapping pain conditions, including fibromyalgia, chronic fatigue, and irritable bowel syndromes. Data from 6 participating MAPP testing sites were pooled for analysis. Participants with UCPPS (n = 153) exhibited an intermediate pain sensitivity phenotype: they were less sensitive relative to the mixed pain group (n = 35) but significantly more sensitive than healthy controls (n = 100). Increased pain sensitivity in patients with UCPPS was associated with both higher levels of clinical pain severity and more painful body areas outside the pelvic region. Exploratory analyses in participants with UCPPS revealed that pain sensitivity increased during periods of urologic symptom flare and that less pressure pain sensitivity at baseline was associated with a greater likelihood of subsequent genitourinary pain improvement 1 year later. The finding that individuals with UCPPS demonstrate nonpelvic pain hypersensitivity that is related to clinical symptoms suggests that central nervous system mechanisms of pain amplification contribute to UCPPS.

COMPARATIVE ANALYSIS OF THE METHODS OF ANESTHETIC MAINTENANCE IN PATIENTS WITH DIABETES WITH THE SYNDROME OF DIABETIC FOOT REQUIRING OPERATIVE INTERVENTION

Introduction: In the present article we draw a comparison between such types of regional anesthesia (RA) as unilateral spinal anesthesia (USA), traditional spinal anesthesia (SA) and block anesthesia of peripheral nerve trunk (block anesthesia of sciatic nerve (BASN) on the side of operative intervention) during surgical treatment of patients with the syndrome of diabetic foot. The aim of the article is to compare effectiveness, reliability and safety of such methods of RA as unilateral and traditional spinal anesthesia, as well as block anesthesia of sciatic nerve on the side of operative intervention. Materials and methods: 96 patients with the syndrome of diabetic foot, who received treatment in the department of purulent surgery, were examined. All patients underwent operative interventions of varying degrees of complexity depending on the nature and seriousness of damage degree of extremities, in terms of RA types under investigation. Effectiveness of regional block anesthesia, the time when anesthesia takes effect, duration and deepness were evaluated. Results: It should be noted that USA, as a variant of pain management during operations of foot, provides the most adequate level of surgical pain management in comparison with the other types of anesthesia. During block anesthesia of sciatic nerve more than half of patients are not provided with 100% surgical analgesia, which can lead to additional medicamentous analgosedation. According to the results obtained, pain sensitivity in patients after BASN is reliably higher than in patients after USA and SA in all stages of the study. Conclusions: RA is the main method of choice during operations on foot in comparison with the methods of general anesthesia. Unilateral spinal anesthesia is carried out with the use of smaller amount of anesthetic than traditional spinal anesthesia and block anesthesia of peripheral nerve trunk, which significantly reduces sympathectomy area and leads to the stable hemodynamic during the peri-operative period.

The relationship between catastrophizing and altered pain sensitivity in patients with chronic low-back pain.

Changes in central pain processing have been shown in patients with chronic low-back pain (cLBP). We used quantitative sensory testing methods to identify differences in pain sensitization between patients with cLBP (N = 167) and healthy controls (N = 33). Results indicated that, compared with healthy pain-free controls, cLBP patients showed increased sensitivity and greater painful aftersensations for mechanical pressure and pin-prick stimuli and lower tactile spatial acuity in the 2-point discrimination task (ps < 0.05). Then, we examined the role of pain catastrophizing as a mediator of the group differences in pain sensitization. We found that catastrophizing partially accounted for group differences in pressure required to produce moderate pain. Finally, we examined the relationship between pain sensitization, catastrophizing, and clinical pain among patients with cLBP. We found that catastrophizing and deep-tissue pressure pain were associated with greater pain intensity in the past month, week, and at the visit as well as low-back pain bothersomeness. Furthermore, deep-tissue pressure pain mediated the associations between catastrophizing and both pain in the past month and low-back pain severity. Taken together, these results indicate that not only do patients with cLBP demonstrate increased pain sensitization and decreased sensitivity to innocuous stimuli, but these changes are also linked with increased catastrophizing. Furthermore, both catastrophizing and sensitization are associated with increased clinical pain among cLBP patients.