Cluster Analysis of an International Pressure Pain Threshold Database Identifies 4 Meaningful Subgroups of Adults With Mechanical Neck Pain

Pain catastrophizing is associated with pain thresholds for heat, cold and pressure in women with chronic pelvic pain

Background and aims Psychological traits such as pain catastrophizing may play a role in the development of chronic pelvic pain (CPP). Pain catastrophizing is the tendency to amplify negative cognitive and emotional pain processes. The Pain Catastrophizing Scale (PCS) assesses elements of pain catastrophizing divided into three subgroups of factors (rumination, helplessness and magnification). Previous studies have shown associations between CPP and increased pain sensitivity, widespread generalized hyperalgesia, and decreased pain thresholds, but the relation between pain catastrophizing and specific pain thresholds has not yet been widely examined in this patient group. The aims of this study were (a) to determine if catastrophizing is increased in women with CPP compared with pain-free women, (b) to assess the importance of pain catastrophizing, psychological distress variables, and subjective pain sensitivity for pain thresholds of heat, cold and pressure in these two groups, and (c) to determine whether psychological variables or pain thresholds best contribute to the differentiation between CPP and controls. Methods Thirty-seven women with chronic pelvic pain who underwent diagnostic laparoscopy on the suspicion of endometriosis participated along with 55 healthy and pain-free controls. All underwent quantitative sensory testing on six locations on the body to determine heat (HPT), cold (CPT) and pressure (PPT) pain thresholds. The PCS, the Pain Sensitivity Questionnaire (PSQ), the Hospital Anxiety Depression Scale, (HADS) demographics and clinical data were collected prospectively. Principal component analysis and orthogonal partial least square regressions were used to assess the associations between PCS scores and pain thresholds. Results The women with CPP scored significantly higher on PCS than the healthy controls. PCS-helplessness, PCS-rumination and HADS-depression were significantly associated with pain thresholds for the whole group. In the CPP group, PCS-rumination, body mass index and PSQ were significant regressors for HPT and CPT. The PCS and the HADS subscales were strongly intercorrelated in women with CPP and were stronger regressors of group membership than the three pain thresholds. In the group of healthy control women, no relationships were found to be significant. The psychological variables were somewhat stronger significant regressors than pain thresholds (also significant) for group membership. Conclusions Women with CPP have significantly higher pain catastrophizing scores than women without CPP. The pain catastrophizing rumination factor is significantly associated with pain thresholds of heat and cold in CPP women. PCS and HADS are strongly intercorrelated and PSQ correlates positively with these variables. It seems that the psychological variables are important for group differentiation. Implications The results clearly indicate the need for a multimodal assessment (bio-psycho-social) of CPP patients including psychological symptoms such as catastrophizing, anxiety and depression. The registration of semi-objective pain thresholds captures both specific pain sensitivity information (mechanical pressure, cold or heat) and the degree of wide spread pain hypersensitivity. There is a need for future larger studies investigating whether certain profiles in the clinical presentations (including pain thresholds and psychological variables) are associated with outcomes after different types of interventions.

Enhanced amygdala-frontal operculum functional connectivity during rest in women with chronic neck pain: Associations with impaired conditioned pain modulation

BACKGROUND

Chronic neck pain is a leading cause of disability worldwide, affecting the lives of millions of people. Research investigating functional brain alterations in relation to somatosensory function is necessary to better understand mechanisms underlying pain development and maintenance in individuals with chronic neck pain, yet remains scarce. This case-control study aimed to examine resting-state functional connectivity alterations and associations with pain outcomes, self-reported central sensitization-related symptoms and quantitative sensory testing (QST) measures in patients with chronic non-traumatic (idiopathic/CINP) neck pain and chronic traumatic (whiplash associated/CWAD) neck pain compared to pain-free controls.

METHODS

Resting-state functional magnetic resonance images were acquired in 107 female participants (38 CINP, 37 CWAD, 32 healthy controls). After data pre-processing, seed-to-seed analyses were conducted focusing on resting-state functional connectivity involving pre-defined regions of interest that have previously been observed to be structurally or functionally altered and/or associated with pain-related measures in this patient population.

RESULTS

Findings demonstrate enhanced left amygdala functional coupling during rest with the left frontal operculum in women with CINP and CWAD compared to controls. This increased resting-state functional connectivity was associated with more self-reported symptoms related to central sensitization and decreased efficacy of conditioned pain modulation. Furthermore, enhanced connectivity between the left amygdala and left frontal orbital cortex, and between the left pallidum and the left frontal operculum was observed only in patients with CWAD compared to healthy controls. In patients, additional associations between local hyperalgesia and enhanced connectivity between the left superior parietal cortex and the left and right precentral gyrus were found.

CONCLUSIONS

In line with our hypotheses, patients with CWAD showed the most pronounced alterations in resting-state functional connectivity, encompassing subcortical limbic (amygdala) and basal ganglia (pallidum), and ventral frontal regions (frontal operculum, orbitofrontal cortex) when compared to CINP and controls. Findings are generally in line with the idea of a continuum, in absence of significant group differences across CINP and CWAD. Enhanced amygdala-frontal operculum functional connectivity was the most robust and only connectivity pair in the cluster that was associated with QST (i.e., dynamic QST; endogenous pain inhibition), and that was observed in both patient groups. In addition, independent of group differences, enhanced resting-state functional connectivity between superior parietal cortex (involved in attention) and primary motor cortex was associated with static QST (i.e., greater local hyperalgesia). Taken together, our findings show a key role for enhanced amygdala-ventral frontal circuitry in chronic neck pain, and its association with diminished endogenous pain inhibition further emphasizes the link between cognitive-affective and sensory modulations of pain in women with chronic non-traumatic and traumatic neck pain.

Enhanced Pronociceptive and Disrupted Antinociceptive Mechanisms in Nonspecific Chronic Neck Pain

OBJECTIVE

Evidence suggests altered pronociceptive and antinociceptive mechanisms in many chronic pain conditions. Knowledge about these mechanisms in nonspecific chronic neck pain (NSNP) would improve understanding of the causes and the design of more effective treatments. Pressure pain threshold (PPT) is often used to assess presence of altered nociceptive processing in NSNP; however, its usefulness to detect this is yet to be established. The purpose of this study was to determine the functional status of temporal summation of second pain (TSSP) and conditioned pain modulation (CPM) in NSNP and to characterize the association of both measures with PPT and clinical features of NSNP.

METHODS

Thirty-two participants with NSNP (mean [SD] age = 44 [11] years; 27 female) and 32 age- and sex-matched healthy controls were recruited. TSSP was assessed using an electrical stimulus at the dorsum of the hand, and CPM was evaluated with the Cold Pressor Test. PPT was assessed bilaterally at the neck and tibialis anterior muscles.

RESULTS

Participants with NSNP showed greater TSPP (mean difference = 0.23; 95% CI = 0.46-0.01; Cohen d = 0.51) and lower CPM (mean difference = 19.44; 95% CI = 10.42-28.46; Cohen d = 1.09). Pooled data from all participants showed lower PPTs at the neck than the tibialis anterior. However, PPT measures did not differ between groups at either location. PPT measures were not correlated with CPM and TSP.

CONCLUSION

NSNP is associated with enhanced pronociceptive and impaired antinociceptive mechanisms, which may explain long-lasting pain and failure of some treatments to resolve symptoms. However, due to the observational nature of this study, a clear cause-effect relationship cannot be established. Normal PPT values in the clinic should not be interpreted as absence of altered nociceptive processing.

IMPACT

This study fills in some gaps in knowledge. Changes in central nociceptive processing may explain persistent and recurrent symptoms in NSNP and failure of treatments to obtain long-lasting relief. Further research is required to ascertain if TSSP and CPM assessment in the clinic may help predict physical therapy treatment outcome. Whether symptomatic relief with physical therapy is mediated by an improvement in TSSP and CPM should also be explored. PPTs were unaltered in participants with NSNP despite evidence of impairment in the central pain modulatory systems. Normal PPTs should not be interpreted as evidence of unaltered central pain-related processing.

Application and utility of a clinical framework for spinally referred neck-arm pain: A cross-sectional and longitudinal study protocol

BACKGROUND

The clinical presentation of neck-arm pain is heterogeneous with varying underlying pain types (nociceptive/neuropathic/mixed) and pain mechanisms (peripheral/central sensitization). A mechanism-based clinical framework for spinally referred pain has been proposed, which classifies into (1) somatic pain, (2) neural mechanosensitivity, (3) radicular pain, (4) radiculopathy and mixed pain presentations. This study aims to (i) investigate the application of the clinical framework in patients with neck-arm pain, (ii) determine their somatosensory, clinical and psychosocial profile and (iii) observe their clinical course over time.

METHOD

We describe a study protocol. Patients with unilateral neck-arm pain (n = 180) will undergo a clinical examination, after which they will be classified into subgroups according to the proposed clinical framework. Standardized quantitative sensory testing (QST) measurements will be taken in their main pain area and contralateral side. Participants will have to complete questionnaires to assess function (Neck Disability Index), psychosocial factors (Tampa Scale of Kinesiophobia, Pain Catastrophizing Scale, Depression, anxiety and stress scale), neuropathic pain (Douleur Neuropathique 4 Questions, PainDETECT Questionnaire) and central sensitization features (Central Sensitization Inventory). Follow-ups at three, six and 12 months include the baseline questionnaires. The differences of QST data and questionnaire outcomes between and within groups will be analyzed using (M)AN(C)OVA and/or regression models. Repeated measurement analysis of variance or a linear mixed model will be used to calculate the differences between three, six, and 12 months outcomes. Multiple regression models will be used to analyze potential predictors for the clinical course.

CONCLUSION

The rationale for this study is to assess the usability and utility of the proposed clinical framework as well as to identify possible differing somatosensory and psychosocial phenotypes between the subgroups. This could increase our knowledge of the underlying pain mechanisms. The longitudinal analysis may help to assess possible predictors for pain persistency.

INYBI: A New Tool for Self-Myofascial Release of the Suboccipital Muscles in Patients With Chronic Non-Specific Neck Pain: A Randomized Controlled Trial

STUDY DESIGN

A randomized, single-blinded (the outcome assessor was unaware of participants' allocation group) controlled clinical trial.

OBJECTIVE

To investigate the effects of myofascial release therapy (MRT) over the suboccipital muscles, compared with self-MRT using a novel device, the INYBI tool, on pain-related outcomes, active cervical mobility, and vertical mouth opening, in adults with chronic non-specific neck pain (NSNP).

SUMMARY OF BACKGROUND DATA

MRT is used to manage chronic musculoskeletal pain conditions, with purported positive effects. The efficacy of self-MRT, compared with MRT, has been scarcely evaluated.

METHODS

Fifty-eight participants (mean age of 34.6 ± 4.7 yrs; range 21-40 yrs; 77.6% females, 22.4% males) with persistent NSNP agreed to participate, and were equally distributed into an INYBI (n = 29) or a control group (n = 29). Both groups underwent a single 5-minutes intervention session. For participants in the control group, MRT of the suboccipital muscles was performed using the suboccipital muscle inhibition technique, while those in the INYBI group underwent a self-MRT intervention using the INYBI device. Primary measurements were taken of pain intensity (visual analogue scale), local pressure pain sensitivity, as assessed with an algometer, and active cervical range-of-movement. Secondary outcomes included pain-free vertical mouth opening. Outcomes were collected at baseline, immediately after intervention and 45 minutes later.

RESULTS

The analysis of variance (ANOVAs) demonstrated no significant between-groups effect for any variable (all, P > 0.05). In the within-groups comparison, all participants significantly improved pain-related outcomes, and showed similar positive changes for mouth opening. Cervical range-of-movement- mainly increased after intervention for participants in the control group.

CONCLUSION

Both, MRT and self-MRT using the INYBI, are equally effective to enhance self-reported pain intensity, and local pressure pain sensitivity in chronic NSNP patients. For cervical mobility, MRT appears to be slighlty superior, compared with the INYBI, to achieve improvements in this population.

LEVEL OF EVIDENCE

2.

The Effect of High Velocity Low Amplitude Cervical Manipulations on the Musculoskeletal System: Literature Review

In manual therapy, high velocity low amplitude (HVLA) cervical manipulation techniques are frequently used, but often the physiological and biomechanical effects that can be obtained are not completely clear. The techniques are mostly used for the treatment of biomechanical joint dysfunction, but little is yet known about the possibility of using them in order to achieve better performance on healthy subjects. The objective of the study is to describe how cervical manipulation can impact on a musculoskeletal disorder.

A systematic search was carried out on the Pubmed electronic database from the beginning of January to March 2020. Two independent reviewers conducted the screening process through the PRISMA diagram to determine the eligibility of the articles. The inclusion criteria covered randomized controlled trial (RCT) manuscripts published in peer-reviewed journals with individuals of all ages from 2005 to 2020. The included intervention was thrust manipulation or HVLA directed towards the cervical spine region. After reviewing the literature, 21 of 74 articles were considered useful and relevant to the research question.

The results of the research show that HVLA techniques, on subjects with musculoskeletal disorders, are able to influence pain modulation, mobility and strength both in the treated area and at a distance. Cervical manipulations are effective in management of cervicalgia, epicondylalgia, temporomandibular joint disorders and shoulder pain. With regard to results on strength in healthy subjects, given the divergent opinions of the authors, we cannot yet state that manipulation can significantly influence this parameter.

Cervical manipulations can also have risks for the patient if applied when not appropriate but the frequency of complications due to vertebral manipulation are very low. However, the manipulation techniques might be limited by low patients tolerance or the presence of contraindications. In addition, the optimal number of manipulations to be performed and the long-term benefits produced are unknown.

Efficacy of dry needling as an adjunct to manual therapy for patients with chronic mechanical neck pain: a randomised clinical trial

OBJECTIVE

Chronic mechanical neck pain is associated with musculoskeletal tissue alterations. Active trigger points in the trapezius and levator scapulae muscles are common in patients with chronic mechanical neck pain. In this study, we compared the effect of dry needling (DN) combined with manual therapy (MT) to sham dry needling (SDN) combined with MT on pain, pain pressure threshold, cervical range of motion and neck disability in patients with chronic mechanical neck pain.

METHODS

A randomised, single-blind clinical trial was carried out involving 101 participants with chronic mechanical neck pain, divided into an intervention group (DN+MT, n=47) and a control group (SDN+MT, n=54). Participants received two treatment sessions. The intervention group received MT in conjunction with DN of the most mechano-sensitive myofascial trigger point (MTrP). The control group received MT plus SDN. Outcomes measures were: pain intensity (numeric pain rating scale, NPRS), pressure pain threshold (PPT), cervical range of motion (ROM) and neck disability (neck disability index, NDI).

RESULTS

This study found that between-group differences in pain intensity were statistically significant (P<0.01). Pain decreased after the first intervention in the DN+MT group (3.47±0.25 points on the NPRS) and even more so after the second intervention (4.76±0.24 points on the NPRS). After 4 weeks, pain intensity differed from baseline by 4.89±0.27 points on the NPRS. Statistically significant differences (P<0.001) in PPT were also found between the intervention group and the control group. After the first intervention, a significant increase in PPT within the DN+MT group (3.09±0.8 kg/cm²) was observed. Cervical ROM also showed highly statistically significant differences. After 4 weeks, a statistically significant reduction (P<0.001) in NDI was observed between the two groups.

CONCLUSION

Our results show that DN+MT is efficacious and significantly better than SDN+MT at reducing pain intensity, PPT, neck disability and cervical ROM in patients with chronic mechanical neck pain.

LEVEL OF EVIDENCE

1b.

Changes in Cervicocephalic Kinesthetic Sensibility, Widespread Pressure Pain Sensitivity, and Neck Pain After Cervical Thrust Manipulation in Patients With Chronic Mechanical Neck Pain: A Randomized Clinical Trial

OBJECTIVE

The purpose of the current randomized clinical trial was to examine the effects of cervical thrust manipulation or sham manipulation on cervicocephalic kinaesthetic sense, pain, pain-related disability, and pressure pain sensitivity in patients with mechanical neck pain.

METHODS

Fifty-four individuals with neck pain were randomly assigned to receive either a cervical manipulation (right or left) or a sham manipulation. Immediate outcomes included cervical kinesthetic sense as assessed by joint position sense error (JPSE) and pressure pain thresholds (PPTs). At 1 week, neck pain intensity (numerical pain rate scale) and neck pain-related disability (Neck Disability Index [NDI]) outcomes were also collected.

RESULTS

The mixed-model analysis of covariance revealed a significant group × time interaction in favor of the cervical thrust manipulation group for the JPSE on rotation and extension. There was also a significant interaction for changes in PPTs at C5 to C6 and tibialis anterior. At the 1-week follow-up, a significant interaction existed for neck-related disability but not for neck pain at rest, worst pain, or lowest pain experienced the preceding week.

CONCLUSIONS

Our results suggest that cervical spine thrust manipulation improves JPSE, PPT and NDI in participants with chronic mechanical neck pain. Furthermore, changes in JPSE and NDI were large and surpass published minimal detectable changes for these outcome measures. In addition, the effect sizes of PPTs were medium; however, only C5 to C6 zygapophyseal joint exceeded the minimal detectable change. In contrast, cervical thrust manipulation did not improve neck pain intensity at 1 week after the intervention.

Local and Widespread Pressure Pain Hyperalgesia Is Not Side Specific in Females with Unilateral Neck Pain that Can Be Reproduced during Passive Neck Rotation

Current evidence for widespread hyperalgesia in non-specific neck pain (NSNP) is unclear. It is currently recommended to group NSNP patients according to pain-provoking movements. The aim of this study was to investigate local and widespread pain sensitivity in females with unilateral NSNP that is reproducible during passive neck rotation compared with matched controls, and to compare the side specific effect of pain location on pressure pain sensitivity among females with unilateral NSNP. Thirty-six females with unilateral NSNP evoked during passive ipsilateral (n = 20) or contralateral (n = 16) rotation toward the painful side were compared with 20 controls. Participants reported their pain intensity at rest and during passive neck rotation and completed the Neck Disability Index. Pressure pain thresholds (PPTs) were assessed bilaterally over the anterior scalene; the sternocleidomastoid; the levator scapulae; lateral to the spinous process of C6; the median, ulnar, and radial nerves; and the tibialis anterior. The ANOVA revealed lower PPTs in females with unilateral NSNP compared with the controls (all at p < 0.001), but no differences were found between the sides, nor was there any Group × side interaction. Among females with NSNP, those with higher pain intensity during ipsilateral rotation toward the painful side showed lower PPTs over the anterior scalene, median nerve, ulnar nerve, and tibialis anterior (all, p < 0.05) than females with higher pain intensity during contralateral rotation toward the painful side. These findings demonstrated bilateral local and widespread pressure pain hyperalgesia in females with unilateral NSNP that was reproducible during passive neck rotation compared with controls. There was no side specific effect of pain location on PPTs among females with unilateral NSNP.

Pressure Pain Phenotypes in Women Before Breast Cancer Treatment

OBJECTIVES

To explore associations between quantitative sensory testing (QST) and pretreatment pain, physical, and psychological characteristics in women with breast cancer.

SAMPLE & SETTING

41 women with treatment-naive stage 0-III breast cancer at the University of Michigan Comprehensive Cancer Center in Ann Arbor.

METHODS & VARIABLES

Participants completed self-report surveys and QST within the month before breast surgery. Pressure pain thresholds (PPTs) were measured bilaterally at each trapezius with a manual QST algometer. PPT values were split, yielding low, moderate, and high pain sensitivity subgroups. Subgroup self-reported characteristics were compared using Spearman's correlation, chi-square, and one-way analysis of variance.

RESULTS

Lower PPT (higher sensitivity) was associated with higher levels of pain interference and maladaptive pain cognitions. The high-sensitivity group reported higher pain severities, interference, and catastrophizing and lower belief in internal locus of pain control than the low-sensitivity group.

IMPLICATIONS FOR NURSING

Individualized interventions for maladaptive pain cognitions before surgery may reduce pain sensitivity and the severity of chronic pain developed after surgery.

Development of the circumduction metric for identification of cervical motion impairment

INTRODUCTION

Chronic neck pain results in considerable personal, clinical, and societal burden. It consistently ranks among the top three pain-related reasons for seeking healthcare. Despite its prevalence, neck pain is difficult to both assess and treat. Quantitative approaches are required since diagnostic imaging techniques rarely provide information on movement-related neck pain, and most common clinical assessment tools are limited to single plane motion measurement.

METHODS

In this study, the ability of an inertial measurement unit to document the cervical motion characteristics of 28 people with chronic neck pain and 23 healthy controls was assessed. A total of six circumduction metrics and one neck circumduction trajectory model were proposed as identification metrics.

RESULTS

Five metrics demonstrated significant differences between the two groups. The neck circumduction trajectory model successfully distinguished between the two groups.

DISCUSSION

The evaluation of the proposed metrics provides proof of concept that novel metrics can be captured with relative ease in the clinical setting using an inexpensive wearable sensor headband. The derivation of the proposed model may open new lines of inquiry into the clinical utility of assessing the multiplanar movement of cervical circumduction. The results obtained from this study also provide additional insight for the development of a sensitive, quantifiable and real-world neck evaluation strategies.

Repositioning error, pressure pain threshold, catastrophizing and anxiety in adolescents with chronic idiopathic neck pain

BACKGROUND

Impaired proprioception, increased pain sensitivity, higher levels of anxiety and catastrophizing are present in adults with chronic idiopathic neck pain. Despite the high prevalence of neck pain, studies in adolescents are scarce.

OBJECTIVES

The main aim was to compare pressure pain thresholds (PPTs) and joint repositioning error (JRE) between adolescents with chronic idiopathic neck pain and adolescents without neck pain. Secondary aims were to compare these groups for catastrophizing and anxiety and to investigate the association between PPTs, JRE and psychosocial variables and pain characteristics.

METHODS

80 adolescents (40 with and 40 without chronic neck pain) were assessed for: neck repositioning error, neck, upper trapezius and tibialis anterior PPTs, anxiety and catastrophizing. Neck pain was characterized in terms of intensity, frequency, duration and associated disability. MANCOVA was used for between group comparisons and Pearson and Spearman coefficients for correlational analysis.

RESULTS

Adolescents with neck pain showed higher levels of catastrophizing (p < 0.001) and anxiety (trait: p < 0.001; state: p = 0.028), lower PPTs (p < 0.001) and higher JRE (p < 0.001) than asymptomatic controls. Pain intensity, frequency and duration were moderately correlated with anxiety, and disability was moderately correlated with anxiety (r between 0.43 and 0.50, p < 0.05) and catastrophizing (r = 0.40, p < 0.05).

CONCLUSIONS

This study suggests that functional changes and maladaptive cognitive processes are present in adolescents with neck pain aged 16-18 years old. These findings need to be replicated in future studies.