Non-pain Groups Research Articles

Effect of neuroticism on genetic susceptibility to depression in chronic pain versus non-pain groups: a genome-wide by trait interaction study

Effect of neuroticism on genetic susceptibility to depression in chronic pain versus non-pain groups: a genome-wide by trait interaction study

Low back pain and lumbar multifidus cross-sectional area, multifidus activation, and low back force in healthcare workers

IntroductionHealthcare workers are required to engage in repetitive actions when handling patients which leads to widespread low back pain in this population. Many variables are related to low back pain including repetitive motions and abnormal multifidus size and activation. This research sought to observe the relationship between low back pain and three variables in healthcare workers specifically: peak low back force when boosting a patient, multifidus cross-sectional area, and multifidus activation. Materials and methodsThis cross-sectional, correlational study included 35 healthcare workers who currently work in inpatient hospital, acute hospital, or skilled nursing settings, and engage in patient handling as part of their job. Force and motion data were collected with motion capture and in-ground force plates and processed to estimate low back forces. Multifidus cross-sectional area was measured with ultrasound while activation was measured using surface electromyography. ResultsThere was not a significant difference in peak low back force between pain and nonpain groups. There was a significant difference in multifidus cross-sectional area at 2 of the 3 levels measured (L5 and S1). Lastly, there was not a significant difference in multifidus activation. ConclusionsPeak low back force during patient handling and lumbar multifidus activation do not seem to be a factor in pain in healthcare workers. Multifidus cross-sectional area is correlated with pain in this population indicating smaller multifidus may increase the likelihood of experiencing pain. Further work should be done to confirm this finding and offer potential solutions. Relevance to industryDiscovering factors in and ways to alleviate low back pain in healthcare workers is essential to the longevity of these professionals in their respective careers.

Midurethral Sling Removal or Revision in Women with Chronic Pain.

The objectives of this study are (1) to estimate the incidence of midurethral sling revision/removal in women with preexisting pain diagnoses versus those without these diagnoses and (2) to describe associations between numbers and type of pain diagnoses with revision/removal. Women who underwent midurethral sling surgery between 2009 through 2014 were identified in the MarketScan database and tracked and December 31, 2014. Patients with preoperative chronic pain diagnoses (fibromyalgia, endometriosis, irritable bowel, dyspareunia, low back pain, temporomandibular joint syndrome, interstitial cystitis, pelvic/perineal pain) were compared with controls (those without these diagnoses) regarding mesh sling revision/removal. Logistic regression identified variables associated with mesh revision/removal, and survival analysis compared timing of mesh removal/revision. There were 161,459 women who underwent midurethral sling surgery (pain, 83,484; nonpain, 77,975). Pain and nonpain groups differed in age (52.1 vs 53.5 years, P < 0.01) and insurance status (P < 0.01), with the pain group more commonly living in the South or West. Mean follow-up was 42.3 months. Cumulative risk for sling revision/removal was higher in patients with 1 pain diagnosis relative to controls (relative risk, 1.54; 95% confidence interval [CI], 1.41-1.54). Risks increased with increased pain diagnoses (≥4 diagnoses; relative risk, 3.13; 95% CI, 2.81-3.47). Pelvic pain conditions had greatest odds of mesh revision/removal (dyspareunia adjusted odds ratio [aOR], 2.44; 95% CI, 2.23-2.63; interstitial cystitis aOR, 1.46; 95% CI, 1.27-1.66; pelvic/perineal pain aOR, 1.41; 95% CI, 1.33-1.48). Co-occurrence of dyspareunia and interstitial cystitis or pelvic/perineal pain had 12.7% cumulative incidence of sling revision/removal. Cox proportional hazards revealed greatest risk for those with pelvic pain conditions (hazard ratio, 2.40; 95% CI, 2.13-2.70). Chronic pain diagnoses increased risk of midurethral sling revision/removal; pelvic pain and numbers of diagnoses increased this risk.

Plasma inflammatory cytokines and treatment-resistant depression with comorbid pain: improvement by ketamine

BackgroundTreatment-resistant depression (TRD) and pain frequently coexist clinically. Ketamine has analgesic and antidepressant effects, but few studies have evaluated individual differences in antidepressant outcomes to repeated ketamine in TRD patients with comorbid pain. Our aims were to determine the difference in ketamine’s antidepressant effects in TRD patients with or without pain and then to examine whether inflammatory cytokines might contribute to ketamine’s effect.MethodsSixty-six patients with TRD received six infusions of ketamine. Plasma levels of 19 inflammatory cytokines were assessed at baseline and post-infusion (day 13 and day 26) using the Luminex assay. Plasma inflammatory cytokines of sixty healthy controls (HCs) were also examined.ResultsTRD patients with pain had a higher antidepressant response rate (χ2 = 4.062, P = 0.044) and remission rate (χ2 = 4.062, P = 0.044) than patients without pain. Before ketamine treatment, GM-CSF and IL-6 levels were higher in the pain group than in the non-pain and HC groups. In the pain group, levels of TNF-α and IL-6 at day 13 and GM-CSF, fractalkine, IFN-γ, IL-10, MIP-3α, IL-12P70, IL-17α, IL-1β, IL-2, IL-4, IL-23, IL-5, IL-6, IL-7, MIP-1β, and TNF-α at day 26 were lower than those at baseline; in the non-pain group, TNF-α levels at day 13 and day 26 were lower than those at baseline. In the pain group, the changes of IL-6 were associated with improvement in pain intensity (β = 0.333, P = 0.001) and depressive symptoms (β = 0.478, P = 0.005) at day 13. Path analysis showed the direct (β = 2.995, P = 0.028) and indirect (β = 0.867, P = 0.042) effects of changes of IL-6 on improvement in depressive symptoms both were statistically significant.ConclusionThis study suggested that an elevated inflammatory response plays a critical role in individual differences in TRD patients with or without pain. Ketamine showed great antidepressant and analgesic effects in TRD patients with pain, which may be related to its effects on modulating inflammation.Trial registrationChiCTR, ChiCTR-OOC-17012239. Registered on 26 May 2017

Static Balance Modification during the Workday in Assembly Chain Workers with and without Current Low Back Pain.

Background: Low back pain (LBP) is a common recurrent pathology among assembly chain workers. This population tends to spend most of the workday in a static standing posture and handling loads, with balance being essential for correct job performance. LBP is related to poorer postural control, so balance could be affected in this condition. Methods: The purpose of the present study is to analyze the deterioration of static balance generated by work activity in a prolonged standing position. We assess sway with a pressure platform at three moments of the workday (before, during, and after work), comparing the different balance parameters in 22 manufacturing plant workers with (17) and without (5) LBP. Results: In the pre-work capture, an independent t-test showed no significant differences between the pain and non-pain groups’ static balance parameters. Between the pre- and mid-workday captures, a two-way ANOVA with repeated measures showed a significant decrease in the medial-lateral center of pressure displacement with open eyes in workers with LBP. Conclusions: workers with low back pain do not show a greater deterioration in static balance than workers without pain during the workday.

Impingement pain affects kinematics of breast cancer survivors in work-related functional tasks

BackgroundBreast cancer survivors may encounter upper limb morbidities post-surgery. It is currently unclear how these impairments affect arm kinematics, particularly during functional task performance. This investigation examined upper body kinematics during functional tasks for breast cancer survivors and an age-matched control group. MethodsFifty women (aged 35–65) participated: 25 breast cancer survivors who had undergone mastectomy and 25 age-range matched controls. Following basic clinical evaluation, including shoulder impingement tests, motion of the torso and upper limbs were tracked during six upper limb-focused functional tasks from which torso, scapular, and thoracohumeral angles were calculated. Between-group differences were evaluated with independent t-tests (p < .05). The breast cancer group was then divided based upon impingement tests and differences between the three new groups were tested with one-way ANOVAs (p < .05). FindingsBreast cancer survivors had higher disability scores, lower range of motion, and lower performance scores. The largest kinematic differences existed between the breast cancer survivors with impingement pain and the two non-pain groups. During overhead tasks, right peak scapular upward rotation was significantly reduced (d = 0.80–1.11) in the breast cancer survivors with impingement pain. This group also demonstrated trends of decreased peak humeral abduction and internal rotation at extreme postures (d = 0.54–0.78). These alterations are consistent with kinematics considered high risk for rotator cuff injury development. InterpretationImpingement pain in breast cancer survivors influences functional task performance and may be more important to consider than self-reported disability when evaluating pain and potential injury development.

Over-triage occurs when considering the patient's pain in Korean Triage and Acuity Scale (KTAS).

BackgroundThe Korean Triage and Acuity Scale (KTAS) was developed based on the Canadian Emergency Department Triage and Acuity Scale. In patients with pain, to determine the KTAS level, the pain scale is considered; however, since the degree of pain is subjective, this may affect the accuracy of KTAS. The purpose of this study was to evaluate the accuracy of KTAS in predicting patient's severity with the degree of pain used as a modifier.MethodA retrospective observational cohort study was conducted in an urban tertiary hospital emergency department (ED). We investigated patients over 16 years old from January to June 2016. The patients were divided into the pain and non-pain groups according to whether the degree of pain was used as a modifier or not. We compared the predictive power of KTAS on the urgency of patients between the two groups. Acute area registration in the ED, emergency procedure, emergency operation, hospitalization, intensive care unit admission, and 7-day mortality were used as markers to determine urgent patients.ResultsOverall, 24,253 patients were included in the study, with 9,175 (37.8%) in the pain group. The proportions of patients with KTAS 1–3 were 61.4% in the pain and 75.6% in the non-pain groups. Among patients with KTAS 2–3, the proportion of urgent patients was higher in the non-pain group than the pain group (p<0.001). The odds ratios for urgent patients at each KTAS level revealed a more evident discriminatory power of KTAS for urgent patients in the non-pain group. The predictability of KTAS for urgent patients was higher in the non-pain group than the pain group (area under the curve; 0.736 vs. 0.765, p-value <0.001).ConclusionsConsidering the degree of pain with KTAS led to overestimation of patient severity and had a negative impact on the predictability of KTAS for urgent patients.

A Survey of Work-Related Pain Prevalence Among Construction Workers in Hong Kong: A Case-Control Study.

Construction workers undertake demanding physical work and face high risk of injuries in poor working environments. This case-control study investigated the extent of their musculoskeletal pain incidence at work. A total of 2021 construction workers in different trades were interviewed on-site in a survey from December 2017 to December 2018. The survey results revealed that the pain prevalence of the subjects in the last 24 h was 10.6 %. The worst and top most common pain spots caused by work were central lower back, left/right shoulders, and knees. Regarding pain management, their most common method was to ignore the pain (21.4%). The average percentage of pain relief after receiving treatment in the 24 h was 37.12%. Besides, significant differences were found between the pain and non-pain groups regarding their employment duration in current job or their average sleep duration in the 24 h. The study showed that those with multiple and bilateral pain sites had pain interference on their living activities.

Pain Induced by Rheumatoid Arthritis and Acupoint Skin Resistance

Dear Professor Andrasik, I enjoyed reading a recent article by Turner et al. (2013) in your journal. The article was a comparison between the acupoint-skin resistance of patients with Rheumatoid Arthritis (RA) and that of healthy counterparts in which the skin resistance was found higher in the RA group; the authors concluded that the measurement of skin resistance at the acupoints can differentiate between the pain (RA) and the non-pain (healthy) groups. But, I would like to express my opinions on their interpretations.

Pain and sensory dysfunction 6 to 12 months after inguinal herniotomy.

Inguinal hernia repair is associated with a 5%-30% incidence of chronic pain, but the pathogenesis remains unknown. We therefore evaluated pain and sensory dysfunction by quantitative sensory testing 6-12 mo after open hemiorrhaphy. Before sensory testing, all patients (n = 72) completed a short-form McGill Pain Questionnaire and a functional impairment questionnaire. Sensory dysfunction in the incisional area was evaluated by quantification of thermal and mechanical thresholds, by mechanical pain responses (von Frey/pressure algometry), and by areas of pinprick hypoesthesia and tactile allodynia. The incidence of chronic pain was 28% (20 of 72). Quantitative sensory testing and pressure algometry did not demonstrate differences between the pain and nonpain groups, except for a small but significant increase in pain response to von Frey hair and brush stimulation in the pain group. Hypoesthesia, or tactile allodynia, in the incisional area was observed in 51% (37 of 72) of the patients, but the incidence did not differ significantly between the pain group and the nonpain group (14 of 20 versus 23 of 52; P > 0.3). We concluded that cutaneous hypoesthesia, or tactile allodynia, is common after inguinal hemiotomy but has a low specificity for chronic postherniotomy pain. Factors other than nerve damage may be involved in the development of chronic posthemiotomy pain.

Antenatal women with or without pelvic pain can be characterized by generalized or segmental hypoalgesia in late pregnancy

Abstract: The aims of the present study were to determine the influence of pregnancy on somatosensory responses in women with or without pelvic/lumbosacral pain. Thirty pregnant women participated and were divided into pain (n [equals] 12) and nonpain (n [equals] 18) groups on the basis of pain complaints and positive pain-provoking tests associated with pelvic or lumbosacral pain during the current pregnancy. In the pain group, 9 reported initial pain in trimester 1, 2 in trimester 2, and 1 in trimester 3. Quantitative sensory testing with pressure pain threshold (PPT), heat pain threshold (HPT), and tactile threshold (TT) was performed once during each of the 3 trimesters at referred pain sites (sacrum, back, and pubis) and no pain control sites (thigh, arm, and sternum). All subjects in the pain group reported back pain, and 91% also had pain at the sacrum and pubis. The pain group exhibited significantly greater pain sensitivity than the nonpain group. The HPT and PPT were higher in trimester 3 as compared to trimesters 1 and 2 (P [lt ] .012). The increase in thresholds, or hypoalgesia, was generalized and present at both referred pain and control sites in the pain group. In the nonpain group hypoalgesia was localized to the presumed referred pain sites at the back and sacrum. There were no significant variations in the TT in any trimester. The study demonstrates for the first time that hypoalgesia in late pregnancy is generalized in women with pelvic pain and localized in women without pelvic pain. This suggests that the descending noxious inhibitory system is activated in late pregnancy and is probably more intense and generally activated in women with pelvic pain and only segmentally activated in women without pain. [copy ] 2002 by the American Pain Society

Clinical considerations in the use of surface electromyography: Three experimental studies

Background: The validity and applicability of erector spinae electromyogram (EMG) use in clinical practice is questionable. Differences in the amplitude of the EMG signal between populations with low back pain (LBP) and controls have been hypothesized but not sufficiently documented. Objective: To examine issues of EMG asymmetry and repeatability in populations with LBP and populations without LBPin 3 separate studies. Study Design: Three separate experimental research studies. Methods: Study 1 examined the intraclass correlation of the EMG signal of the paraspinal musculature at L3 on 3 separate days during quiet stance with use of 3 different normalization techniques: percent maximum voluntary contraction, percent submaximal voluntary contraction, and percent averaged submaximal contractions. Study 2 used a population with chronic LBP to compare the bilateral asymmetry of paraspinal musculature in segments exhibiting pain with segments not exhibiting pain during quiet stance. A 1-way analysis of variance was used to compare differences between asymmetry scores in the pain and nonpain groups. In study 3, persons with LBP and persons in the control group had the dynamic asymmetry of paraspinal musculature compared during forward bending. A cross-correlation coefficient assessing bilateral muscle activity was calculated for each subject and differences between groups were evaluated using a 1-way analysis of variance. Results: Study 1: Subjects showed excellent repeatability (ICC > 0.75) regardless of the normalization technique. Study 2: During quiet stance no differences were found in bilateral asymmetry between painful and nonpainful motion segments. Study 3: No differences existed in bilateral dynamic symmetry for the upper erector spinae; however, differences between groups did exist for the lower erector spinae. Conclusion: Repeatability of the EMG signal during quiet stance is acceptable; however, bilateral asymmetry may not be a definitive indicator of dysfunction. (J Manipulative Physiol Ther 2002;25:293-9)

Chronic pain after SCI. A patient survey

A survey of chronic pain experience after spinal cord injury. To investigate the prevalence, severity and impact of chronic pain amongst spinal cord injury (SCI) patients in our region, and assess the need for additional resources to address the problem. A postal questionnaire was sent to 216 spinal cord injury patients (10% of the Yorkshire regional spinal injury database). Yorkshire region, UK. A response was received from 67% of the patients. Seventy-nine per cent of patients said they presently suffered with pain, with 39% describing it as severe. Comparison of pain and non-pain groups using chi-squared analysis showed that complete injury was significantly more likely than incomplete injury to result in chronic pain (P<0.05), and increased severity of pain (P<0.05). 43% of patients with pain said they required further treatment for it. Chronic pain had a significant impact on daily activities and was a major factor in causing unemployment (18%) and depression (39%). The study confirms that pain is a major problem in SCI patients which is not currently being adequately addressed. A multidisciplinary approach to management and prospective studies of treatments are required in order to reduce the prevalence and severity of pain in these patients. Spinal Cord (2000) 38, 611 - 614.

A comparison of the burst activity of lateral thalamic neurons in chronic pain and non-pain patients

Thalamic neurons are known to switch their firing from a tonic pattern during wakefulness to a bursting pattern during sleep. Several studies have described the existence of bursting activity in awake chronic pain patients and have suggested that this activity is abnormal and may be related to their pain. However, we have frequently observed bursting activity in awake non-pain patients suggesting that there may not be a causal relationship between thalamic bursting activity and chronic pain. To examine this issue more rigorously we compared the incidence and pattern of bursting activity of lateral thalamic neurons of both pain and non-pain patients in a state of wakefulness. Recordings were obtained from lateral thalamic areas of different groups of patients ( n=91) suffering from pain disorders (e.g. anaesthesia dolorosa, phantom limb pain, trigeminal neuralgia, post-stroke pain) and motor disorders (e.g. Parkinson's disease, essential tremor) during stereotactic surgical procedures for the treatment of pain and movement disorders. Burst indices (the number of bursting cells per electrode track) were computed for all the explorations in the two groups. The burst indices in the pain and non-pain groups (1.73±0.28 and 1.14±0.16, respectively) were not significantly different from each other. The bursts were analyzed to see if they fulfilled the criteria of low-threshold calcium spike (LTS)-evoked bursts characterized by (i) a shortening of the first interspike interval with an increase in the number of interspike intervals in the burst and also (ii) a progressive prolongation of successive interspike intervals. LTS-evoked bursts were identified in 27/47 (57%) bursting cells in pain patients and 15/32 (47%) cells in non-pain patients. These data demonstrate that the occurrence of bursting activity and of LTS-evoked bursts in the human thalamus is prevalent in both pain and non-pain patients. This suggests that the bursting activity of thalamic neurons in pain patients is not necessarily related to the occurrence of their pain.

The Minnesota Multiphasic Personality Inventory (MMPI) Hysteria (Hy) scale: scoring bodily concern and psychological denial subscales in chronic back pain patients.

Chronic back pain patients were compared to two nonpain comparison groups on Minnesota Multiphasic Personality Inventory (MMPI) Hysteria (Hy) scores and scores on two Hy subscales: Bodily Concern and Psychological Denial. Pain subjects had significantly higher scores on the Bodily Concern Subscale and lower scores on the Psychological Denial Subscale than nonpain subjects with similar elevated Hy scores. However, pain subjects had Psychological Denial scores similar to those of subjects with normal MMPI profiles, despite significantly higher Hy scores. These findings are interpreted to support the hypothesis that, among pain patients, Hy elevations are partially accounted for by the endorsement of a disproportionate number of Bodily Concern items. Finally, within pain patients, scores on the Bodily Concern subscale were significantly related to more indices of pain duration and severity than were scores on the Psychological Denial subscale. The potential clinical utility of scoring these subscales is discussed.