Corrugator Muscle Activity Associated with Pressure Pain in Adults with Neck/Shoulder Pain

Background and Objectives: No studies have reported corrugator muscle activity associated with pain in people with pain. This study aimed to develop an objective pain assessment method using corrugator muscle activity with pressure pain stimulation to the skeletal muscle. Methods: Participants were 20 adults (a mean ± SD age of 22.0 ± 3.1 years) with chronic neck/shoulder pain. Surface electromyography (sEMG) of corrugator muscle activity at rest (baseline) and without and with pressure pain stimulation applied to the most painful tender point in the shoulder was recorded. Participants evaluated the intensity of the neck/shoulder pain and the sensory and affective components of pain with pressure stimulation using a visual analogue scale (VAS). The percentages of integrated sEMG (% corrugator activity) without and with pressure pain stimulation to the baseline integrated sEMG were compared, and the relationships between the % corrugator activity and the sensory and affective components of pain VAS scores were evaluated. Results: Without pressure stimulation, an increase in corrugator muscle activity due to chronic neck/shoulder pain was not observed. The % corrugator activity with pressure pain stimulation was significantly higher than that without stimulation (p < 0.01). A significant positive correlation between corrugator muscle activity and the affective components of pain VAS scores with pressure stimulation was found (ρ = 0.465, p = 0.039) and a tendency of positive correlation was found for the sensory component of pain VAS scores (ρ = 0.423, p = 0.063). Conclusions: The increase in corrugator muscle activity with pressure pain stimulation to the tender point in adults with chronic neck/shoulder pain was observed, although increased corrugator muscle activity resulting from the chronic neck/shoulder pain was not. These findings suggest that corrugator muscle activity with pressure pain stimulation can be a useful objective indication for tender point sensitivity assessment in the skeletal muscle with pain.

Suggestion Timing Moderates the Effects of Prior Pain Experiences on Pain Perception

Two common elements in patient care are reoccurring painful events (eg, blood draws) and verbal suggestions from others for lessened pain. Research shows that verbal suggestions for lower pain can decrease subsequent pain perception from novel noxious stimuli, but it is less clear how these suggestions and prior painful experiences combine to influence the perception of a reoccurring painful event. The presented experiment tested the hypothesis that the order of these 2 factors influence pain perception for a reoccurring painful event. All participants (702 healthy college-student volunteers, 58% women, 85.5% White) experienced a novel painful event on one arm, then again on their other arm (now a familiar pain event). Participants who received the suggestion that they can tolerate more pain on the second arm relative to the first from the outset, before the initial pain event, perceived relatively less pain during the repeated event as compared to participants who received the same suggestion after the first painful event or no-suggestion (control). Given many pain events within medical contexts are, or become, familiar to patients, further researching the timing at which patients receive verbal suggestions for lower pain can inform practices to optimize the therapeutic, pain-reducing potential of such suggestions. PERSPECTIVE: Providing suggestions that a familiar pain event (ie, the second of 2) will be less painful than a prior event can reduce perceived pain for the familiar event depending on when it is presented. These findings can inform practices to optimize the therapeutic potential of verbal suggestions for reduced pain.

Evaluation of a scoring system for the detection of central sensitization among women with chronic pelvic pain

BACKGROUND

Central sensitization is frequently associated with chronic pelvic pain and requires specific management. The pain is described as hypersensitivity to an innocuous stimulus that is both widespread and persistent. However, no study has evaluated if central sensitization can be measured objectively with neurophysiological tests in the pelvic and perineal area to prove this concept in women with chronic pelvic pain.

OBJECTIVE

This study aimed to evaluate nociceptive thresholds (primary objective) and spatial and temporal diffusion of pain among women with chronic pelvic pain and high or low scores of central sensitization.

STUDY DESIGN

This prospective, assessor-blinded, comparative study compared a cohort of women with chronic pelvic pain and a high (>5/10; n=29) vs low (<5/10; n=24) score of sensitization according to the Convergences PP criteria. Participants underwent a noninvasive bladder sensory test, a rectal barostat test, and a muscular (algometer) and a vulvar (vulvagesiometer) sensory test. Poststimulation pain (minutes), quality of life (Medical Outcomes Study 36-Item Short Form Survey), and psychological state, comprising anxiety (State-Trait Anxiety Inventory), depression (Beck Depression Inventory Short Form), and catastrophizing (Pain Catastrophizing Scale), were assessed.

RESULTS

The participants mostly suffered from endometriosis (35.8%), irritable bowel syndrome (35.8%), bladder pain syndrome (32.1%), and vestibulodynia (28.3%). Baseline characteristics were similar. Women with a high sensitization score had more painful diseases diagnosed (2.7±1.3 vs 1.6±0.8; P=.002) and suffered for longer (11±8 vs 6±5 years; P=.028) than participants with a low score. The bladder maximum capacity was equivalent between participants (399±168 vs 465±164 mL; P=.18). However, the pain felt at each cystometric threshold was significantly increased in women with a high sensitization score. No difference was identified for the rectal pain pressure step (29.3±5.5 vs 30.7±6.5 mm Hg; P=.38). Rectal compliance was decreased in women with a high sensitization score with a considerable increase in pain felt. The average of pain pressure thresholds at the 5 vulvar sites tested was decreased in these participants (162.5±90.5 vs 358.7±196.5 g; P=.0003). Similar results were found for the average of the pain pressure thresholds at 6 muscles tested (1.34±0.41 vs 2.63±1.52 kg/m2; P=.0002). A longer period was needed for patients with high sensitization score to obtain a VAS <3 out of 10 after the stimulation of the bladder (4.52±5.26 vs 1.27±2.96 minutes; P=.01), the rectum (3.75±3.81 vs 1.19±1.23 minutes; P=.009), and the muscles (1.46±1.69 vs 0.64±0.40 minutes; P=.002). The psychological state was equivalent between groups. No association was found between the sensory thresholds and the psychological state results. The physical component of the quality of life score was reduced in women with high sensitization score (P=.0005), with no difference in the mental component.

CONCLUSION

Using neurophysiological tests, this study showed that there are objective elements to assess for the presence of central sensitization, independently of psychological factors.

Treatment of Vestibulodynia with Submucosal Injections of IncobotulinumtoxinA into Targeted Painful Points: An Open-Label Exploratory Study

The studies carried out to date on vulvodynia treatment with botulinum neurotoxin type A (BoNT/A) have followed generic injection protocols and reported contradictory outcomes on its effects. The aim of the present study was thus to propose a protocol for injecting BoNT/A into targeted painful points, to comprehensively assess the clinical effect of BoNT/A treatment and identify the risk/protective factors for successful treatment. Thirty-five vestibulodynia patients were treated with submucosal injections of incobotulinumtoxinA and assessed 8, 12 and 24 weeks after their treatment. Their clinical and pelvic statuses were assessed from self-reported questionnaires (Visual Analogue Scale (VAS), Female Sexual Function Index (FSFI), Marinoff's Dyspareunia Scale (MDS), Hospital Anxiety and Depression Scale (HADS), Catastrophizing Scale (CS)), physical examinations and surface electromyography (sEMG). The patients reported a reduction in provoked vestibulodynia (FSFI, p < 0.01; Collapse

Key Words

• algometer
• botulinum toxin A
• sexual function
• surface electromyography
• vestibulodynia
• vulvodynia

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MESH Headings

• Humans
• Female
• Vulvodynia/drug therapy
• Botulinum Toxins, Type A/therapeutic use
• Pain
• Pain Threshold

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Affiliation(s)

Paula Villa-Muñoz Servicio De Ginecología Y Obstetricia, Hospital Universitari I Politècnic La Fe, 46026 Valencia, Spain; (P.V.-M.); (F.J.N.-A.)
Monica Albaladejo-Belmonte Centro De Investigación E Innovación En Bioingeniería (CI2B), Universitat Politècnica De València, 46022 Valencia, Spain;
Francisco J. Nohales-Alfonso Servicio De Ginecología Y Obstetricia, Hospital Universitari I Politècnic La Fe, 46026 Valencia, Spain; (P.V.-M.); (F.J.N.-A.)
Jose Alberola-Rubio Sonda Devices S.L., 46004 Valencia, Spain;
Javier Garcia-Casado Centro De Investigación E Innovación En Bioingeniería (CI2B), Universitat Politècnica De València, 46022 Valencia, Spain;

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Contribution to the Study of Perioperative Factors Affecting the Restoration of Dog's Mobility after Femoral Head and Neck Excision: A Clinical Study in 30 Dogs

This study aimed to compare postoperative analgesia and the time of limb weight bearing induced by the intraoperative administration of a local anesthetic at the site of the femoral head and neck excision (FHNE) in dogs, with and without the administration of preoperative epidural anesthesia. Additionally, the impact of postoperative opioid drug administration on weight-bearing time was examined. This randomized, blinded, prospective clinical study included 30 client-owned dogs. The dogs were randomly divided into three groups (A, B, C), each further divided into two subgroups (A1, A2, B1, B2, C1, C2). Group A received epidural anesthesia and ropivacaine at the ostectomy site, Group B received only ropivacaine, and Group C served as the control group. Subgroup 1 received a non-steroidal anti-inflammatory drug postoperatively, while Subgroup 2 had tramadol added to their regimen. Pain assessment was conducted using the University of Melbourne Pain Scale (UMPS) and an algometer. The study concluded that multimodal analgesia, utilizing all the aforementioned analgesic techniques, resulted in faster limb weight bearing for dogs undergoing FHNE.

Pain-Pressure Threshold Changes throughout Repeated Assessments with No Sex Related Differences

Algometers are commonly used to measure the pain-pressure threshold (PPT) in various tissues, such as muscle, tendons, or fascia. However, to date, it is not clear if the repeated application of a PPT assessment can adjust the pain thresholds of the various muscles. Therefore, the purpose of this study was to investigate the repeated application of PPT tests (20 times) in the elbow flexor, knee extensor, and ankle plantar flexor muscles in both sexes. In total, 30 volunteers (15 females, 15 males) were tested for their PPT using an algometer on the respective muscles in random order. We found no significant difference in the PPT between the sexes. Moreover, there was an increase in the PPT in the elbow flexors and knee extensors, starting with the eighth and ninth assessments (out of 20), respectively, compared to the second assessment. Additionally, there was a tendency to change between the first assessment and all the other assessments. In addition, there was no clinically relevant change for the ankle plantar flexor muscles. Consequently, we can recommend that between two and a maximum of seven PPT assessments should be applied so as not to overestimate the PPT. This is important information for further studies, as well as for clinical applications.

Abdominal examination using pressure pain threshold algometer reflecting clinical characteristics of complementary and alternative medicine in Korea: A systematic review and a brief proposal

BACKGROUND

A review was conducted to determine a pressure algometry measurement during abdominal examination that reflects clinical settings of traditional Korean medicine.

METHODS

After reviewing the previous studies, we have proposed a reference index, common posture and method for performing pressure algometry during abdominal examination. Keyword search using eight databases was performed. To identify the characteristics of pressure algometry during abdominal examination, keywords (e.g., abdomen, abdominal examination) were searched in national Korean databases, including Korean studies Information System (KISS), Research Information Sharing Service (RISS), and Oriental Medicine Advanced Searching Integrated System (OASIS). To examine the methods of measuring pressure pain threshold (PPT) with validity and reliability, combination keywords (e.g., PPT, pressure algometry, pressure pain, validity, reliability) were searched in Pubmed, Cochrane library, Google scholar, Ovid Embase, and China Knowledge Resource Integrated Database (CNKI).

RESULTS

A total of 652 articles were identified, and 22 relevant articles were included. The following main indices are proposed as a standardized pressure algometry method during abdominal examination: unit of measurements, measuring tools, target locations, pressure area, pressure rate, posture of patients, and evaluators. Based on the results of the review combined with clinical practice, useful indices for pressure algometer during abdominal examination were derived (target location: CV 12, unit of measurement: MPa, pressure area: 4 cm2, pressure rate: 0.098 MPa/s, posture of patient: supine position, number, and intervals of measurement: three consecutive measurements at intervals of 30 seconds, 5 minutes rest prior to commencement). Postures and method sequence of pressure algometry during abdominal examination are also proposed.

CONCLUSIONS

Using standardized indices, postures and method for abdominal examination in clinical settings will help make objective assessments.

Mechanical Vibration and Chewing Gum Methods in Orthodontic Pain Relief

OBJECTIVE

The aim of this study was to investigate the pain relief effects of chewing gum and mechanical vibration methods on orthodontic pain caused by the initial archwire.

METHODS

In this study, 57 patients, having a 3-6 mm maxillary dental crowding and non-extraction treatment modality were includ- ed. The pressure pain thresholds of the subjects were measured. Patients were distributed equally by sex and randomly allocated into 3 groups: mechanical vibration, chewing gum, and control. The fixed orthodontic treatment was started in the upper jaw only. In the first and second groups, mechanical vibration was applied and sugar-free gum was chewed, respectively. The third group was used as the control. The pain perceptions were measured using the Visual Analog Scale. Kruskal-Wallis and Friedman tests were used for statistical analysis.

RESULTS

The groups were similar at the beginning of the study in terms of age and algometer scores (P = .138 and P =.155, respective- ly). Statistical significant differences in the Visual Analog Scale scores among the groups could not be detected at any time point. The highest pain scores were detected at the 24th hour of treatment in all 3 groups. There was no statistically significant difference in the highest pain level among the groups (P = .279).

CONCLUSION

Although the average pain values were perceived as lower, particularly in the mechanical vibration group, the temporary displacement of the teeth has no clinically significant pain relief effect on orthodontic pain.

Localized and widespread pressure pain hypersensitivity in patients with episodic or chronic migraine: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis compared pressure pain sensitivity in trigeminal, cervical spine and remote pain-free areas between migraine patients and headache-free controls considering diagnosis (episodic versus chronic) and sex.Databases and data treatment: Electronic databases were searched for cross-sectional or prospective case-control studies comparing pressure pain thresholds between migraine and headache-free controls. Data were extracted by two reviewers. The risk of bias and methodological quality was assessed by Newcastle-Ottawa Quality Assessment Scale. Meta-analyses of trigeminal, extra-trigeminal (cervical spine) and remote pain-free areas were compared. Frequency of migraine and sex were taken into account. Mean differences (MD) and random effects were calculated.

RESULTS

Eighteen studies were included. Patients with migraine showed lower pressure pain thresholds than headache-free controls: trigeminal (MD -71.33 kPa, 95%CI -92.14 to -50.53), cervical spine (MD -68.50 kPa, 95%CI -84.67 to -52.33), and remote pain-free (MD -62.49 kPa, 95%CI -99.52 to -25.45) areas. Differences were consistently significant for episodic migraine in all locations, but only significant in the trigeminal area for chronic migraine (MD -67.36 kOPa, 95%CI -101.31 to -33.42). Overall, women had lower pressure pain thresholds than men. The methodological quality of most studies (66.7%) was good. The results showed a high heterogeneity.

CONCLUSION

This meta-analysis found low to high quality evidence showing lower pressure pain thresholds in trigeminal, extra-trigeminal, and remote pain-free areas in migraine sufferers when compared with headache-free controls. Hypersensitivity to pressure pain locally and widespread was consistently observed in episodic migraine, but locally in chronic migraine as compared to headache-free controls. Women with migraine were more sensitive than men.Registration number: https://doi.org/10.17605/OSF.IO/YJTAK.

Pressure Algometry Evaluation of Two Occlusal Splint Designs in Bruxism Management-Randomized, Controlled Clinical Trial

The aim of this pilot study was to evaluate the short-term effectiveness of two different occlusal devices and their impact on the pressure pain threshold (PPT) values among patients who reported to the Dental Prosthetics Outpatient Clinic of Pomeranian Medical University (Szczecin, Poland) and who were diagnosed with probable bruxism. Two groups were formed (A and B) to which patients were assigned randomly. Each group used a different occlusal splint for bruxism management. The occlusal appliance by Okeson, or the bimaxillary splint, was used overnight by each patient for 30 days of the study. The PPT was measured twice, at the first visit and after 30 days of using each occlusal device, with Wagner Paintest FPX 25 algometer. Bruxism was diagnosed based on data from the patient's medical history and from the physical examination. Nocturnal Bruxism Criteria according to the International Classification of Sleep Disorders (Third Edition) was used for the patient's evaluation. Results: similar pain factor (PF) reduction was observed in both the examined groups, regardless of the device used; canine guidance and no guidance were similarly effective in terms of increasing pain resilience.

Assessing Preoperative Pain Sensitivity Predicts the Postoperative Analgesic Requirement and Recovery after Total Knee Arthroplasty: A Prospective Study of 178 Patients

BACKGROUND

The aim of this article is to study the correlation between preoperative pain sensitivity and postoperative pain and analgesic requirements for patients undergoing primary total knee arthroplasty.

METHODS

Between December 2018 and April 2019, the pain sensitivity of 178 consecutive patients undergoing primary total knee arthroplasty was assessed preoperatively with a digital algometer. The patients reported the VAS (visual analog scale) score at 3 instances of needle prick (phlebotomy, glucometer blood sugar, intradermal antibiotic test dose), during the range of movements and completed the Depression Anxiety Stress Scale score. Postoperative VAS score, analgesic requirement, and physiotherapy milestones were recorded in all these patients on day 0 to day 4.

RESULTS

The average age of the patients was 64.13 years and 69.1% were females. Females had lower mean algometry values (56.12 ± 12.77 [standard deviation]) compared to males (71.09 ± 18.78 [standard deviation]) (P < .001). Higher Depression Anxiety Stress Scale correlated with lower algometry values (P < .001). The postoperative VAS score was 2.54 ± 0.59 on the day of surgery which increased to 3.27 ± 0.69 on day 1 after mobilization (P < .001) and reduced to 1.67 ± 0.62 on day 4. Low algometer score correlated with higher postoperative VAS score (P < .05), increased analgesic requirement, and opioid utilization (P < .001), delay in achieving an optimum range of movements (P < .001) and independent ambulation (P < .001).

CONCLUSION

Preoperative assessment of pain sensitivity predicts postoperative analgesic requirements and recovery. Patients with a lower pain threshold should be counseled preoperatively and also receive a better titration of analgesics perioperatively and prolonged physiotherapy.

Evidence of localized and widespread pressure pain hypersensitivity in patients with tension-type headache: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis evaluates pressure pain sensitivity values in symptomatic and distant pain-free areas comparing individuals with tension-type headache to controls.

DATABASES AND DATA TREATMENT

Electronic databases were searched for cross-sectional or prospective case-control studies comparing pressure pain thresholds in patients with tension-type headache to headache-free controls. Data were extracted by three reviewers. The methodological quality was assessed by the Newcastle-Ottawa Quality Assessment Scale. Meta-analyses of trigeminal, extra-trigeminal (neck) and distant pain-free areas in tension-type headache were compared to headache-free controls. Frequency of tension-type headache and gender were taken into account.

RESULTS

Twenty studies were included. Patients with tension-type headache exhibited lower pressure pain thresholds than headache-free controls: Trigeminal (MD -49.11 kPa, 95% CI -66.05 to -32.17), cervical spine (MD -88.17 kPa, 95% CI -108.43 to -67.92) and distant pain-free areas (MD -98.43 kPa, 95% CI -136.78 to -60.09). Differences were significant for chronic, episodic, and mixed episodic and chronic tension-type headache within the trigeminal and neck (symptomatic areas), but only significant for chronic tension-type headache (MD -102.86, 95% CI -139.47 to -66.25 kPa) for distant pain-free areas. In general, women had lower pressure pain thresholds than men. The methodological quality ranged from fair (45%) to good (40%). The results showed a high heterogeneity and publication bias.

CONCLUSION

This first meta-analysis addressing pressure pain thresholds differences in symptomatic and distant pain-free areas between patients with tension-type headache and controls found low to moderate evidence supporting the presence of pressure pain hypersensitivity in the trigeminal and neck areas in tension-type headache in comparison with headache-free controls. Sensitivity to pressure pain was widespread only in chronic, not episodic, tension-type headache (moderate evidence).Registration number: https://doi.org/10.17605/OSF.IO/R29HY.

Inter- and intra-observer reliability of quantitative sensory testing performed with the SMall animal ALGOmeter (SMALGO) to evaluate pain associated with feline gingivostomatitis

OBJECTIVES

The aim of this study was to evaluate the inter- and intra-observer reliability of quantitative sensory testing performed with the SMall animal ALGOmeter (SMALGO) in healthy cats and in cats with chronic gingivostomatitis (CGS), and to evaluate the SMALGO as a tool to detect and quantify pain in cats with CGS.

METHODS

Thirty cats from a private shelter were included and assigned to one of two groups: group C (healthy cats; n = 15) or group CGS (cats with CGS; n = 15). In all cats the mechanical thresholds were measured with the SMALGO, with the sensor tip applied to the superior lip above the canine root, by two independent investigators (A, experienced; B, unexperienced), on two different occasions (day 1 and day 2) with a 24 h interval. A CGS scale was used in the diseased cats to assess the severity of the condition. For the reliability analysis, intra-class correlation coefficients (ICCs) were calculated. Other statistical tests used were Pearson correlation coefficient and a paired t-test.

RESULTS

The inter- and intra-observer levels of agreement were fair (ICC = 0.50) and good, respectively (ICC = 0.73 for investigator A; ICC = 0.60 for investigator B). However, the thresholds measured in healthy cats (169 ± 59 g) did not differ from those obtained from diseased cats (156 ± 82 g; P = 0.35). There was no correlation between the scores of the CGS scale and the thresholds measured in diseased cats (Pearson correlation coefficient = 0.047; P = 0.87).

CONCLUSIONS AND RELEVANCE

Quantitative sensory testing performed with the SMALGO in cats is repeatable and reliable, regardless of the expertise of the investigator. However, the findings of this study suggest that the mechanical thresholds measured with the SMALGO may not be a valuable indicator of pain in cats with CGS.

Algometer Precision for Quantifying Mechanical Nociceptive Threshold When Applied to the Udder of Lactating Dairy Cows

Objectives of this study were to: (1) quantify the reliability of an algometer for measuring mechanical nociceptive thresholds when applied to the udder of dairy cows; and (2) evaluate whether covariates, such as cow characteristics or time of the day, would influence algometer measurements. This prospective study was performed in a university herd of 37 lactating cows during five consecutive days, involving two raters. Two types of measurement were obtained: one qualitative binary measure (i.e., reaction vs. no reaction) and one quantitative measure presented in kilograms (i.e., mechanical nociceptive threshold, MNT) for the cows that reacted. Kappa statistics were used to investigate test-retest and inter-rater reliability for the qualitative measure, while concordance correlation coefficient (CCC) and limits of agreement plot were used for the quantitative measure. Whether algometer measurements were influenced by several covariates (i.e., time of the day, level of milk production, days in milk, and parity) was then evaluated using logistic or linear regression models, depending on the outcome. The algometer was moderately reliable; there was moderate test-retest reliability (Kappa = 0.53; CCC = 0.58) and inter-rater reliability (Kappa = 0.42; CCC = 0.54). The MNT varied substantially as a function of time of the day and parity. This is the first study reporting reliability of a pressure algometer for quantifying MNT and investigating covariates possibly affecting this measurement when applied to the udder of dairy cows. It is concluded that the use of an algometer for quantifying MNT on the udder is only moderately repeatable and is influenced by extraneous covariates. Its usage in research setting to quantify changes in sensitivity at the udder level should, therefore, be considered very cautiously or it should be further developed.

The James A. Rand Young Investigator's Award: Battling the Opioid Epidemic with Prospective Pain Threshold Measurement

BACKGROUND

Responsible analgesic prescribing is paramount in the opioid epidemic era, yet no standardized protocol exists. We aim to (1) quantify and correlate outpatient opioid need after total knee and hip arthroplasties (TKA and THA) with preoperative objective pain pressure thresholds (PPTs) and subjective pain measures and (2) report incidence of nonsurgical opioid prescriptions 6 weeks postoperatively.

METHODS

Prospectively, PPTs were measured using an algometer with a maximum force of 20 pounds in 160 consecutive patients (90 TKA and 70 THA). Two locations were tested: operative joint (medial epicondyle TKA and lateral iliac crest THA) and ipsilateral olecranon for systemic control. Visual Analog Score, Pain Severity Score, Pain Interference Score, and subjective pain threshold were obtained. Six-week outpatient narcotic consumption morphine equivalents recorded and prescriptions crosschecked with the state Controlled Substance Reporting System. Multivariate analysis was performed to evaluate local and/or systemic PPT and subjective measures with narcotic consumption.

RESULTS

Average operative site and systemic PPT was 6.91 and 7.72 pounds force, respectively. Subjective averages: Visual Analog Score 7.14, Pain Severity Score 5.05, Pain Interference Score 5.16, and perceived threshold 6.77. Six-week average outpatient narcotic consumption was 314.9 morphine equivalents or 125 five milligram oxycodones. Twenty percent received opioids from outside providers. Linear regression revealed a negative correlation between operative site PPT (-0.26; P = .047) and systemic PPT (-0.31; P = .021). Subjective pain metrics failed to meet significance.

CONCLUSION

This novel study demonstrated a statistically significant negative correlation between preoperative pain threshold and outpatient narcotic consumption. Twenty percent of patients received opioid prescriptions outside orthopedic providers in the 6 weeks after surgery highlighting the importance of interdisciplinary communication.

Protocol: Testing the Relevance of Acupuncture Theory in the Treatment of Myofascial Pain in the Upper Trapezius Muscle

A protocol for a prospective single-blind parallel four-arm randomized placebo-controlled trial with repeated measures was designed to test the effects of various acupuncture methods compared with sham. Eighty self-selected participants with myofascial pain in the upper trapezius muscle were randomized into four groups. Group 1 received acupuncture to a myofascial trigger point (MTrP) in the upper trapezius. Group 2 received acupuncture to the MTrP in addition to relevant distal points. Group 3 received acupuncture to the relevant distal points only. Group 4 received a sham treatment to both the MTrP and distal points using a deactivated acupuncture laser device. Treatment was applied four times within 2 weeks with outcomes measured throughout the trial and at 2 weeks and 4 weeks posttreatment. Outcome measurements were a 100-mm visual analog pain scale, SF-36, pressure pain threshold, Neck Disability Index, the Upper Extremity Functional Index, lateral flexion in the neck, McGill Pain Questionnaire, Massachusetts General Hospital Acupuncture Sensation Scale, Working Alliance Inventory (short form), and the Credibility Expectance Questionnaire. Two-way analysis of variance (ANOVA) with repeated measures were used to assess the differences between groups.

Pressure algometry measurement of canine muscular pain near the thoracolumbar junction: evaluation of a modified technique

OBJECTIVE

To evaluate the utility of pressure algometry for measuring muscular pain in dogs by using a modified technique intended to prevent the development of a learned apprehension response.

STUDY DESIGN

Prospective randomized clinical trial.

ANIMALS

Sixty-three client-owned dogs with a history of restricted comfort or mobility.

METHOD

Pressure algometry was used to measure the mechanical nociceptive threshold (MNT) in eight locations around the thoracolumbar junction. Dogs were assigned to one of two groups: group A dogs (n = 22) were placed on a restricted exercise program, while group B dogs (n = 25) were placed on a restricted exercise program and were administered combined acupuncture and manual therapy treatment (CAMT). After data collection in groups A and B was complete, animals were recruited for a third (control) group, C (n = 16), that had no exercise restriction or treatment. Algometry measurements were performed on four occasions over 28 days using a technique intended to prevent the dogs from developing a learned apprehension response. Measurements from eight locations were pooled and analyzed for changes over time.

RESULTS

Increases in MNTs over time at all locations tested were identified in groups A and B. In group C there were no significant changes in MNT or evidence of a learned apprehension response.

CONCLUSION AND CLINICAL RELEVANCE

MNTs in dogs without exercise restriction or CAMT were consistently repeatable and unchanged over time, indicating that there was no learned apprehension response to pressure algometry using the modified technique. Therefore, the increasing MNT values with time in dogs administered exercise restriction with or without CAMT suggests improved muscular comfort of the thoracolumbar region. Although further research is needed, use of this modified technique should improve the utility of pressure algometry for measuring muscular pain in dogs.

Effects of different frequencies of conventional transcutaneous electrical nerve stimulation on pressure pain threshold and tolerance

BACKGROUND

Pulse frequency is one of the key determinants of analgesic outcomes by transcutaneous electrical nerve stimulation (TENS). However, optimal settings remain unclear.

OBJECTIVE

To compare the effects of different frequencies of TENS, on pressure pain threshold and tolerance.

METHODS

Currents with pulse duration of 110 μs, and pulse frequencies of 60 pps or 150 pps were applied on the volar aspects of the dominant forearms of 20 healthy volunteers, on two consecutive days, in a randomized order. Threshold and tolerance were measured at the beginning, after the 15th and 30th minutes of the applications, and 30 minutes after the applications.

RESULTS

Pressure pain threshold and tolerance values were higher at the 150 pps frequency, at all measurement times (p< 0.05). However, no frequencyXtime interaction and time-dependent changes were found for the outcome measures (p> 0.05).

CONCLUSIONS

These findings established that, at 150 pps conventional TENS, threshold and tolerance values were consistently higher. These results are presented to inform future research regarding optimal conventional TENS parameters and to provide support for clinical applications.

Reliability of four experimental mechanical pain tests in children

Purpose

In order to study pain in children, it is necessary to determine whether pain measurement tools used in adults are reliable measurements in children. The aim of this study was to explore the intrasession reliability of pressure pain thresholds (PPT) in healthy children. Furthermore, the aim was also to study the intersession reliability of the following four tests: (1) Total Tenderness Score; (2) PPT; (3) Visual Analog Scale score at suprapressure pain threshold; and (4) area under the curve (stimulus–response functions for pressure versus pain).

Participants and methods

Twenty-five healthy school children, 8–14 years of age, participated. Test 2, PPT, was repeated three times at 2 minute intervals on the same day to estimate PPT intrasession reliability using Cronbach’s alpha. Tests 1–4 were repeated after median 21 (interquartile range 10.5–22) days, and Pearson’s correlation coefficient was used to describe the intersession reliability.

Results

The PPT test was precise and reliable (Cronbach’s alpha ≥ 0.92). All tests showed a good to excellent correlation between days (intersessions r = 0.66–0.81). There were no indications of significant systematic differences found in any of the four tests between days.

Conclusion

All tests seemed to be reliable measurements in pain evaluation in healthy children aged 8–14 years. Given the small sample size, this conclusion needs to be confirmed in future studies.