Intra- and interrater agreement of pressure pain thresholds in children with orthopedic disorders

Evaluation of the analgesic efficacy of grapiprant compared with robenacoxib in cats undergoing elective ovariohysterectomy in a prospective, randomized, masked, non-inferiority clinical trial

OBJECTIVES

The main objective of this study was to compare the postoperative analgesic effects of grapiprant with those of robenacoxib in cats undergoing ovariohysterectomy (OVH).

METHODS

In total, 37 female cats (age range 4 months-10 years, weighing ⩾2.5 kg) were enrolled in a prospective, randomized, masked, non-inferiority (NI) clinical trial. Cats received oral robenacoxib (1 mg/kg) or grapiprant (2 mg/kg) 2 h before OVH. Analgesia was assessed via the Feline Grimace Scale (FGS), the Glasgow Composite Measure Pain Scale-Feline (CMPS-F), von Frey monofilaments (vFFs) and pressure algometry (ALG) 2 h before treatment administration, at extubation, and 2, 4, 6, 8, 18 and 24 hours after extubation. Hydromorphone (<8 h postoperatively) or buprenorphine (>18 h postoperatively) were administered to cats with scores of ⩾5/20 on CMPS-F and/or ⩾4/10 on FGS. NI margins for CMPS-F and vFFs were set at 3 and -0.2, respectively. A mixed-effect ANOVA was used for FGS scores (P <0.05). Data are reported as mean ± SEM.

RESULTS

The data from 33 cats were analyzed. The upper limit of the 95% confidence interval (CI) (0.35) was less than the NI margin of 3 for CMPS-F, and the lower limit of the 95% CI (0.055) was greater than the NI margin of -0.2 for vFFs, indicating NI of grapiprant. The FGS scores were greater than baseline at extubation for both treatments (1.65 ± 0.63; P = 0.001); however, there was no difference between treatments. There was no difference between treatments, nor treatment by time interaction, for vFFs (P <0.001). The CMPS-F scores for both treatments were higher at extubation but returned to baseline after 4 h (P <0.001). For ALG, there was no difference in treatment or treatment by time interaction. The robenacoxib group had lower pressure readings at extubation and 6 h compared with baseline.

CONCLUSIONS AND RELEVANCE

These results indicate that grapiprant was non-inferior to robenacoxib for mitigating postsurgical pain in cats after OVH performed via ventral celiotomy. The impact of grapiprant for analgesia in OVH via the flank is unknown.

Virtual reality increases pressure pain threshold and lowers anxiety in children compared with control and non-immersive control-A randomized, crossover trial

BACKGROUND

Virtual reality (VR) is a promising non-pharmacological pain intervention because it may not only distract but also modulate pain by immersing the user in a three-dimensional 360° alternate reality. In children, VR has been reported to reduce clinical pain and anxiety during medical procedures. However, the effect of immersive VR on pain and anxiety remains to be investigated in randomized controlled trials (RCT). The aim of the present crossover RCT was to assess the effect of VR on pressure pain threshold (PPT) and anxiety level measured with the modified Yale Preoperative Anxiety Scale (mYPAS) in children in a controlled experimental setting.

METHODS

Seventy-two children (mean age 10.2 (6-14) years) were randomized to 24 sequences of four interventions (immersive VR Game, immersive VR video, tablet: 2D video and control: small talk). Outcome measures PPT, mYPAS and heart rate were assessed before and after each intervention.

RESULTS

PPT increased significantly during VR game (PPTdiff): 136 kPa (CI 112; 161), p < 0.0001 and VR Video (PPTdiff): 122 kPa (CI 91; 153), p < 0.0001. Also, anxiety levels significantly decreased during both VR game (mYPASdiff: -7 points (-8 to -5), p < 0.0001) and VR video (mYPASdiff: -6 points (CI -7; -4), p < 0.0001).

CONCLUSIONS

VR had a marked beneficial effect on PPT and anxiety compared with the control interventions: 2D video and small talk. Thus, immersive VR had a distinct modulatory effect on pain and anxiety in a well-controlled experimental setting. Immersive VR was effective and feasible in children and can act as a valid tool for non-pharmacological pain and anxiety management.

SIGNIFICANCE

Paediatric immersive VR seems to be beneficial although well-controlled studies are pending. We investigated whether immersive VR can modulate children's threshold for pain and anxiety level in an experimental well-controlled setting. We document a modulatory pain threshold increase and anxiety level decrease compared with extensive control conditions. Paediatric immersive VR is effective, feasible and valid for non-pharmacological pain and anxiety management. All efforts to reach the goal that no child should experience pain or anxiety when exposed to medical procedures.

Conditioned Pain Modulation in Children: The Effects of Painful and Nonpainful Conditioning Stimuli

Conditioned pain modulation (CPM), a psychophysical measure in which 1 pain stimulus (conditioning stimulus) is used to inhibit another pain stimulus (test stimulus), is an important indicator of endogenous pain inhibition in adults, but is understudied in children. Preliminary evidence suggests that CPM effects are present in healthy children and are more robust in adolescents. However, developmental differences in younger children are not well documented and few studies control for potential distraction effects of the conditioning stimulus (CS). Participants were 54 healthy children aged 6 to 12 years. After a baseline pressure pain threshold (PPT) test, participants underwent 2 conditioning trials in which PPT was assessed while they placed their left hand in a water bath maintained at either 12 °C (painful CS) or 22 °C (nonpainful sham CS) in counterbalanced order. Results revealed a significant CPM effect. PPT values were significantly higher relative to baseline during the painful CS trial; PPT during the nonpainful CS trial did not differ from baseline. There were no significant age differences in magnitude of CPM effect. The results indicate that children as young as 6 years of age demonstrate CPM, suggesting that descending inhibitory pathways may be better developed in young children than previously thought. PERSPECTIVE: This study was successful in producing inhibitory CPM effects in physically healthy children while controlling for sensory distraction. The findings provide strong evidence that the obtained CPM responses cannot be attributed to sensory distraction or other nonspecific effects. Future studies could utilize CPM paradigms to study various aspects of pediatric endogenous pain inhibition, in order to better predict pain responses and improve interventions.

Differential Risk Factor Profiles in the Prediction of General and Pain-Specific Functional Limitations 12 Months after Major Pediatric Surgery

Pediatric chronic post-surgical pain is a surgical complication associated with various levels of functional limitation. Two commonly used measures of functional limitations in youth are the Functional Disability Inventory (FDI) and the PROMIS Pediatric Pain Interference Scale (PPIS), where the former is general, and the latter, pain specific. The aim of the present study was to prospectively compare pre-surgical youth and parent risk factors for youth functional limitations, assessed by the FDI and PPIS, 12 months after major pediatric surgery. Risk factors for the FDI and PPIS were compared in 79 dyads consisting of youth (58% female, M = 14.56 years; SD = 2.31) undergoing major surgery and one of their parents. The FDI and PPIS were highly correlated prior to surgery (r = 0.698, p < 0.001) and even more so 12 months after surgery (r = 0.807, p < 0.001). Parent pre-surgical anxiety sensitivity and youth pre-surgical functional disability significantly predicted 12-month FDI (F(6,56) = 4.443, p = 0.001, Adjusted R² = 0.25), whereas parent pre-surgical anxiety sensitivity, trait anxiety, pain anxiety, as well as youth pain-related anxiety and worry significantly predicted 12-month PPIS (F(6,45) = 4.104, p = 0.002, Adjusted R² = 0.27). Risk factors for 12-month general and pain-specific functional limitations differ by dyad member and type. Functional limitations in youth after surgery are predicted by youth and parent factors, however the risk factors differ between the FDI and the PPIS.

Pressure pain thresholds in children before and after surgery: a prospective study

Background and aims This prospective study aimed to assess pressure pain thresholds (PPTs) by pressure algometry and the correlation to postoperative pain in children undergoing orthopaedic surgery. We hypothesized, that the PPTs would decline immediately after elective orthopaedic surgery and return to baseline values at follow-up. Methods Thirty children aged 6-16 years were included. PPTs and intensity of pain (Numerical Rating Scale, NRS) were assessed 3-6 weeks before surgery (baseline), 1-2 h before surgery (Day 0), the first postoperative day (Day 1) and 6-12 weeks after surgery (Follow-up). Results A significant difference of PPTs between the four assessments was seen using the Friedman test for detecting differences across multiple tests and Wilcoxon signed-rank test with a Bonferroni adjustment. The changes in PPTs between baseline (PPTcrus = 248 kPa, PPTthenar = 195 kPa) and day 1 (PPTcrus = 146 kPa, PPTthenar = 161 kPa) showed a decline of PPTs as hypothesized (Zcrus = 2.373, p = 0.018; Zthenar = 0.55, p = 0.581). More surprisingly, a significant decrease in PPTs between baseline and day 0, just before surgery (PPTcrus = 171 kPa, PPTthenar = 179 kPa), was also measured (Zcrus = 2.475, p = 0.013; Zthenar = 2.414, p = 0.016). PPTs were positively correlated to higher age, weight and height; but not to NRS or opioid equivalent use. Conclusions Children undergoing orthopaedic surgery demonstrate significant changes in PPTs over time. The PPTs decrease significantly between baseline and day 0, further decreases the first day postoperatively and returns to baseline values at follow-up. This suggests that other factors than surgery modulate the threshold for pain. Implications Awareness of pressure pain thresholds may help identify children with affected pain perception and hence improve future pain management in children undergoing orthopaedic surgery. Factors as for example anticipatory anxiety, psychological habitus, expected pain, catastrophizing, distraction, physical activity, patient education and preoperative pain medication might play a role in the perception of pain and need further investigation.

Pediatric Chronic Postsurgical Pain And Functional Disability: A Prospective Study Of Risk Factors Up To One Year After Major Surgery

BACKGROUND

Chronic postsurgical pain (CPSP) is a surgical complication associated with increased functional disability, psychological distress, and economic costs. The aims of this paper were to prospectively: (1) examine the incidence of CPSP 6 and 12 months after pediatric major surgery; (2) identify pain intensity and pain unpleasantness trajectories before, and up to 12 months after, surgery; (3) identify pre-operative factors that predict pain trajectory group membership; and (4) identify predictors of 12-month functional disability.

METHODS

This study followed 265 children aged 8-17 years at four time points (pre-surgical [T0], in-hospital [T1], 6 [T2] and 12 [T3] months after surgery). Children and parents completed pain and psychological questionnaires. In-hospital physical activity was monitored using actigraphy.

RESULTS AND DISCUSSION

The incidence of moderate-to-severe CPSP at 6 and 12 months was 35% (95% CI 29.1% to 41.9%) and 38% (95% CI 32.4% to 45.1%), respectively. Three percent (95% CI 1.17% to 6.23%) and 4% (95% CI 1.45% to 6.55%) of children reported using opioids to manage pain at 6 and 12 months, respectively. Growth mixture modeling revealed a two-class trajectory model with a quadratic slope best fit the data for both pain intensity (Bayesian information criterion [BIC] = 3977.03) and pain unpleasantness (BIC = 3644.45) over the 12 months. Preoperative functional disability and cumulative in-hospital opioid consumption predicted pain intensity trajectories. Preoperative functional disability predicted pain unpleasantness trajectories. Preoperative functional disability (OR: 1.05, 95% CI: 1.01 to 1.09) and pain unpleasantness trajectories (OR: 2.59, 95% CI: 1.05 to 6.37) predicted 12-month moderate-to-severe functional disability.

CONCLUSION

Pre-surgical functional disability is the only factor that predicts both 12-month functional disability and the course of pain intensity and pain unpleasantness ratings over the 12-month period.

Reliability of pain pressure threshold algometry in persons with conservatively managed wrist fractures

OBJECTIVE

Wrist fracture is a common injury in Norway. Pressure algometry is widely used to quantify patients' pain threshold in various anatomical locations. The aim of this study was to explore the reliability of pain pressure threshold (PPT) algometry in persons with conservatively managed distal radius fractures.

METHODS

In this cross-sectional study, three raters (A, B, and C) tested the PPT of participants (18-97 years of age) with a unilateral distal radius fracture after removal of the cast. The raters conducted two measurements of both wrists. Intrarater reliability was examined in 75, 50, and 25 participants by Raters A, B, and C, respectively. Interrater reliability was tested in 50 and 25 participants by Rater Pairs A-B and A-C, respectively. Relative reliability was calculated with intraclass correlation coefficient (ICC_1.1 ) and absolute reliability using within-subject standard deviation (S_w ).

RESULTS

There was a significant difference in the PPT between the participants' injured and noninjured wrists (p < .0001). The mean PPT was 29% lower in the injured than in the noninjured wrists, 175 kPa (SD ± 62) versus 248 kPa (SD ± 83). Intrarater reliability (A) of PPT algometry was better in injured wrists than in noninjured wrists (ICC_1.1  = 0.825 vs. 0.765 and S_w  = 27 vs. 43 kPa). Similarly, interrater reliability of PPT algometry was better in injured wrists than in noninjured wrists. In injured wrists, the interrater reliability of PPT algometry between Raters A and B was 0.617 (ICC_1.1 ) and S_w was 51 kPa, and between Raters A and C, the interrater reliability was 0.706 (ICC_1.1 ) and S_w was 48 kPa.

CONCLUSION

PPT algometry is a useful measurement tool with acceptable reliability and thus suitable for monitoring and quantifying pain in persons with conservatively managed wrist fractures. To be more certain that a change has occurred, the same rater should perform the measurements.

Mutations affecting glycinergic neurotransmission in hyperekplexia increase pain sensitivity

See Dickenson (doi:10.1093/brain/awx334) for a scientific commentary on this article.Inhibitory interneurons in the spinal cord use glycine and GABA for fast inhibitory neurotransmission. While there is abundant research on these inhibitory pain pathways in animal models, their relevance in humans remains unclear, largely due to the limited possibility to manipulate selectively these pathways in humans. Hyperekplexia is a rare human disease that is caused by loss-of-function mutations in genes encoding for glycine receptors and glycine transporters. In the present study, we tested whether hyperekplexia patients display altered pain perception or central pain modulation compared with healthy subjects. Seven patients with genetically and clinically confirmed hyperekplexia were compared to 14 healthy age- and sex-matched controls. The following quantitative sensory tests were performed: pressure pain detection threshold (primary outcome), ice water tolerance, single and repeated electrical pain detection thresholds, nociceptive withdrawal reflex threshold, and conditioned pain modulation. Statistical analysis was performed using linear mixed models. Hyperekplexia patients displayed lower pain thresholds than healthy controls for all of the quantitative sensory tests [mean (standard deviation)]: pressure pain detection threshold [273 (170) versus 475 (115) kPa, P = 0.003], ice water tolerance [49.2 (36.5) versus 85.7 (35.0) s, P = 0.015], electrical single pain detection threshold [5.42 (2.64) versus 7.47 (2.62) mA, P = 0.012], electrical repeated pain detection threshold [3.76 (1.41) versus 5.8 (1.73) mA, P = 0.003], and nociceptive withdrawal reflex [7.42 (3.63) versus 14.1 (6.9) mA, P = 0.015]. Conditioned pain modulation was significantly reduced in hyperekplexia [increase to baseline: 53.2 (63.7) versus 105 (57) kPa, P = 0.030]. Our data demonstrate increased pain sensitivity and impaired central pain modulation in hyperekplexia patients, supporting the importance of glycinergic neurotransmission for central pain modulation in humans.

Generalized Hyperalgesia in Children and Adults Diagnosed With Hypermobility Syndrome and Ehlers-Danlos Syndrome Hypermobility Type: A Discriminative Analysis

OBJECTIVE

Lowered pressure-pain thresholds have been demonstrated in adults with Ehlers-Danlos syndrome hypermobility type (EDS-HT), but whether these findings are also present in children is unclear. Therefore, the objectives of the study were to determine whether generalized hyperalgesia is present in children with hypermobility syndrome (HMS)/EDS-HT, explore potential differences in pressure-pain thresholds between children and adults with HMS/EDS-HT, and determine the discriminative value of generalized hyperalgesia.

METHODS

Patients were classified in 1 of 3 groups: HMS/EDS-HT, hypermobile (Beighton score ≥4 of 9), and healthy controls. Descriptive data of age, sex, body mass index, Beighton score, skin laxity, and medication usage were collected. Generalized hyperalgesia was quantified by the average pressure-pain thresholds collected from 12 locations. Confounders collected were pain locations/intensity, fatigue, and psychological distress. Comparisons between children with HMS/EDS-HT and normative values, between children and adults with HMS/EDS-HT, and corrected confounders were analyzed with multivariate analysis of covariance. The discriminative value of generalized hyperalgesia employed to differentiate between HMS/EDS-HT, hypermobility, and controls was quantified with logistic regression.

RESULTS

Significantly lower pressure-pain thresholds were found in children with HMS/EDS-HT compared to normative values (range -22.0% to -59.0%; P ≤ 0.05). When applying a threshold of 30.8 N/cm² for males and 29.0 N/cm² for females, the presence of generalized hyperalgesia discriminated between individuals with HMS/EDS-HT, hypermobility, and healthy controls (odds ratio 6.0).

CONCLUSION

Children and adults with HMS/EDS-HT are characterized by hypermobility, chronic pain, and generalized hyperalgesia. The presence of generalized hyperalgesia may indicate involvement of the central nervous system in the development of chronic pain.

Is One Trial Sufficient to Obtain Excellent Pressure Pain Threshold Reliability in the Low Back of Asymptomatic Individuals? A Test-Retest Study

The assessment of pressure pain threshold (PPT) provides a quantitative value related to the mechanical sensitivity to pain of deep structures. Although excellent reliability of PPT has been reported in numerous anatomical locations, its absolute and relative reliability in the lower back region remains to be determined. Because of the high prevalence of low back pain in the general population and because low back pain is one of the leading causes of disability in industrialized countries, assessing pressure pain thresholds over the low back is particularly of interest. The purpose of this study study was (1) to evaluate the intra- and inter- absolute and relative reliability of PPT within 14 locations covering the low back region of asymptomatic individuals and (2) to determine the number of trial required to ensure reliable PPT measurements. Fifteen asymptomatic subjects were included in this study. PPTs were assessed among 14 anatomical locations in the low back region over two sessions separated by one hour interval. For the two sessions, three PPT assessments were performed on each location. Reliability was assessed computing intraclass correlation coefficients (ICC), standard error of measurement (SEM) and minimum detectable change (MDC) for all possible combinations between trials and sessions. Bland-Altman plots were also generated to assess potential bias in the dataset. Relative reliability for both intra- and inter- session was almost perfect with ICC ranged from 0.85 to 0.99. With respect to the intra-session, no statistical difference was reported for ICCs and SEM regardless of the conducted comparisons between trials. Conversely, for inter-session, ICCs and SEM values were significantly larger when two consecutive PPT measurements were used for data analysis. No significant difference was observed for the comparison between two consecutive measurements and three measurements. Excellent relative and absolute reliabilities were reported for both intra- and inter-session. Reliable measurements can be equally achieved when using the mean of two or three consecutive PPT measurements, as usually proposed in the literature, or with only the first one. Although reliability was almost perfect regardless of the conducted comparison between PPT assessments, our results suggest using two consecutive measurements to obtain higher short term absolute reliability.

Test-retest reliability of a new technique with pressure algometry applied to teeth in healthy Chinese individuals

Pressure pain thresholds (PPTs) have been shown to be useful measures of mechanical pain sensitivity in deep tissues. However, clinical methods for measuring mechanical allodynia or hyperalgesia in teeth have not been reported. The aim of this study was to assess the reliability of PPTs in periodontal ligament of healthy Chinese participants. Twenty healthy young adults participated. Pressure pain thresholds were measured at six teeth and in two directions. The tests included three consecutive trials, in two separate sessions, which were performed on the first day by one examiner. After 1-3 wk, an identical protocol was carried out by two examiners, also in two separate sessions. There were no significant differences between repeated measures for all teeth. The PPTs had excellent reliability with high intraclass coefficients (ICCs) across different sessions (ICC: 0.871-0.956), days (ICC: 0.879-0.951), and examiners (ICC: 0.845-0.950). Pressure pain thresholds applied to the teeth have excellent intra- and inter-examiner agreement in healthy participants. This method may be proposed as an easy and reliable technique to assess mechanical pain sensitivity (e.g. mechanical allodynia and hyperalgesia) in the periodontal ligament, which is associated with endodontic or periodontal conditions.

Manual therapy in the management of a patient with a symptomatic Morton's Neuroma: A case report

Patients with Morton's neuroma are rarely referred to physical therapy. This case reports the resolution of pain, increase in local pressure pain thresholds, and improvement of scores on the Lower Extremity Functional Scale and Foot and Ankle Ability Measure following a course of joint based manual therapy for a patient who had failed standard conservative medical treatment.