Differential blockade, comparative study of different ropivacaine concentrations (0.75%; 0.2%; 0.12%) for ultrasound guided sciatic and femoral nerve blocks in calves: Prospective cross-over study

Pharmacodynamic understanding of the different local anesthetic concentrations allows adapting their use to diverse clinical/surgical procedures, such as intraoperative and/or postoperative analgesia. A crossover study was performed, where 6 calves (5 male and 1 female), weighing 120 ± 28 Kg, were subjected to combined sciatic and femoral nerve block using three ropivacaine concentrations. The treatments were: R0.75, using 0.75% ropivacaine; R0.2, 0.2% ropivacaine; and R0.12%, 0.12% ropivacaine. All treatments were performed with ultrasound and neurostimulation assistance, and a volume of 0.1 mL/kg of the respective local anesthetic solution was administered in each block point. The sites of mechanical nociceptive threshold (MNT) evaluation were based on the calf pelvic limb dermatomes. The proportion between desensitized areas, MNT elevation time and level of ataxia were registered. Elevation of MNT occurred in 100% of the tested areas in the R0.75 and R0.2 treatments, and in 82% of the R0.12 treatment. Mean MNT elevation times were 9.5 ± 0.7 h for R0.75, 6 ± 0.8 for R.02, and 2.4 ± 2.3 for R0.12, differing significantly between all treatments. No difference was observed between MNT elevation time and ataxia duration time, in each treatment. It is concluded that the duration of sensory-motor effects is dose-dependent, but there was not possible to detect block selectivity as the concentrations was reduced. More desensitized areas and extension were obtained with the use of higher concentrations.

The Effect of Capacitive-Resistive Electrical Therapy on Neck Pain and Dysfunction in Horses

Neck pain and stiffness are increasingly recognized in horses and often treated using multimodal pharmaceutical and rehabilitation approaches. In humans, deep tissue heating is reported to reduce neck pain and increase flexibility. The objective of this project was to determine the effects of capacitive-resistive electrical therapy on neck pain and stiffness in horses. A blinded, randomized, controlled clinical trial with 10 horses assigned to active and 10 horses assigned to sham treatment groups. Neck pain, stiffness, and muscle hypertonicity were assessed by manual palpation. Forelimb postural stability was evaluated using a portable media device with built-in inertial sensing components. All outcome parameters were recorded once weekly for four weeks. Using manufacturer recommendations, the treatment group received active capacitive-resistive electrical therapy to the lower cervical region (C4-C7), twice weekly for a total of six treatments, while the control group received a sham (inactive) treatment. Data was analyzed using a mixed model that was fit separately for each response variable. There were no significant differences noted over time or between groups for any outcome parameter evaluated. While neck pain and stiffness decreased by week three in both groups, the improvement was not significant. Limitations include the lack of a definitive pathoanatomic diagnosis of cervical pathology and in vivo temperature measurements. Capacitive-resistive electrical therapy was ineffective in reducing neck pain and dysfunction using the recommended treatment protocols. No short-term adverse effects were noted. Specific clinical applications and effective treatment parameters need further evaluation.

Pressure pain threshold mappings of the infraspinatus muscle in chronic unilateral shoulder pain patients do not reflect generalized hypersensitivity

OBJECTIVES

Increased mechanical sensitivity has been observed on the unaffected side in chronic pain conditions, suggesting generalized or widespread hypersensitivity. However, this cannot be considered as a universal response since this hypersensitivity is inconsistent across muscle pain pathologies. The aim of this study was to assess generalized hypersensitivity in chronic unilateral shoulder pain, using pressure pain threshold (PPT) mappings of the infraspinatus muscle. The proposed evaluation is based on the assessment of PPT on a limited subset of sites, reducing potential habituation or sensitization effects.

METHODS

Twenty-nine patients with unilateral shoulder pain (USP) and twenty-seven healthy volunteers were recruited. PPT was assessed using a manual pressure algometer. Six sites distributed over the infraspinatus muscle were assessed, and three repetitions were performed at each site. Mappings were derived using two-dimensional interpolation.

RESULTS

Lower PPT values were found in the symptomatic side in comparison with the asymptomatic side at all assessment sites (estimated difference: 1.42 ± 0.10 kgf/cm², p < 0.001), but there were no differences among the asymptomatic side of USP patients and any of the sides in healthy volunteers (largest estimated difference: 0.17 ± 0.28 kgf/cm², p = 0.927). Furthermore, the medial region of the infraspinatus muscle showed higher mechanical sensitivity in both healthy volunteers and USP patients.

CONCLUSIONS

These results suggest that USP does not induce generalized hypersensitivity, in contrast with previously reported findings. Physiotherapists could take these results into account for the assessment and treatment of patients with USP.

Instrumental validity and intra/inter-rater reliability of a novel low-cost digital pressure algometer

Background

Pain assessment is a key measure that accompanies treatments in a wide range of clinical settings. A low-cost valid and reliable pressure algometer would allow objective assessment of pressure pain to assist a variety of health professionals. However, the pressure algometer is often expensive, which limits its daily use in both clinical and research settings.

Objectives

This study aimed to assess the instrumental validity, and the intra- and inter-rater reliability of an inexpensive digital adapted pressure algometer.

Methods

A single rater applied 60 random compressions on a force platform. The pressure pain thresholds of 20 volunteers were collected twice (3 days apart) by two raters. The main outcome measurements were as follows: the maximal peak force (in kPa) and the pressure pain threshold (adapted pressure algometer vs. force platform). Cronbach’s α test was used to assess internal consistency. The standard error of measurement provided estimates of measurement error, and the measurement bias was estimated with the Bland–Altman method, with lower and upper limits of agreement.

Results

No differences were observed when comparing the compression results (P = 0.51). The validity and internal intra-rater consistencies ranged from 0.84 to 0.99, and the standard error of measurement from 0.005 to 0.04 kPa. Very strong (r = 0.73–0.74) to near-perfect (r = 0.99) correlations were found, with a low risk of bias for all measurements. The results demonstrated the validity and intra-rater reliability of the digitally adapted pressure algometer. Inter-rater reliability results were moderate (r = 0.55–0.60; Cronbach’s α = 0.71–0.75).

Conclusion

The adapted pressure algometer provide valid and reliable measurements of pressure pain threshold. The results support more widespread use of the pressure pain threshold method among clinicians.

Efficacy of Extracorporeal Shockwave Therapy on Cervical Myofascial Pain Following Neck Dissection Surgery: A Randomized Controlled Trial

Objective

To investigate the efficacy of extracorporeal shockwave therapy (ESWT) on cervical myofascial pain following neck dissection in reducing pain and improving cervical range of motion (ROM).

Methods

Forty-six patients with cervical myofascial pain following neck dissection surgery were recruited and subdivided at random into two equal groups. The ESWT group received ESWT once a week for 4 weeks (0.25 mL/mm², 1,000 shocks) and a topical non-steroidal anti-inflammatory drug (3 times/day for 4 weeks). The control group received only topical NSAID. The pain assessment was done by using the visual analog scale (VAS) and pressure algometry. A cervical ROM device was used for the assessment of the lateral flexion and rotation of the neck ROM on both sides. All measurements were collected at baseline, 2 weeks, and 4 weeks.

Results

The ESWT group revealed a significant improvement in all parameters at post I and post II than did the control group (p>0.001), that revealed a statistical decrease only in the VAS score at post I without any statistical difference in the pain threshold and neck ROM. However, there were statistical differences in all parameters at post II compared to those at pre-treatment and post I (p<0.001).

Conclusion

As a confirmation of the efficacy of ESWT in cervical myofascial pain control following neck dissection, we observed better results with no side effects in the ESWT group (Clinical Trial Registry No. PACTR202002648274347).

Mechanical nociceptive assessment of the equine hoof following distal interphalangeal joint intra-articular anesthesia

Background

With the hypothesis that equine dorsal lamellar tissue can be desensitized by anesthesia injection into distal interphalangeal joint (DIPJ), the objective was to assess the mechanical nociceptive threshold of hoof dorsal lamellae following intra-articular (IA) administration of lidocaine into this joint.

Methods

The DIPJ of the forelimbs of six adult healthy horses were injected with either 5 mL of lidocaine, or 5 mL of lactated Ringer’s solution. Treatments were randomly distributed, with each forelimb undergoing a single treatment. The hooves were evaluated pre- and post-injection at pre-selected times over 4 h, using a pressure algometry model. Mechanical nociceptive thresholds (MNTs) were recorded for the sole (dorsal, palmarolateral, and palmaromedial regions), coronary band (medial, lateral, and dorsal regions), heel bulbs (medial and lateral), and dorsal lamellar region (2 cm and 4 cm distal to the coronary band). The MNT means were compared over time using the Friedman test and between treatments using the Wilcoxon signed-rank test, with values of P < 0.05 considered statistically significant.

Results

There were no differences between treatments for any region of the hoof during the evaluation period. However, MNT values indicating analgesia were recorded in the dorsal lamellar region in 50% of hooves following adminstration of lidocaine into the DIPJ.

Conclusion

The administration of 5 mL of lidocaine into the DIPJ does not significantly increase the mechanical nociceptive threshold of the equine hoof.

Effect of Caudal Traction on Mechanical Nociceptive Thresholds of Epaxial and Pelvic Musculature on a Group of Horses With Signs of Back Pain

Direct muscular attachment from lumbar vertebrae to the caudal vertebrae of the tail suggests that caudal traction, also described as a tail pull, may affect lumbar vertebral segments and/or associated soft tissues in horses. Traction is a commonly used human manual therapy technique used for pain relief and anecdotally observed to relieve pain in horses. However, research is lacking validating the efficacy of manual caudal traction on the horse. The objective of this study was to determine if caudal traction has an effect on mechanical nociceptive thresholds (MNTs) in a group of horses with clinical signs of back pain. Pressure algometry was used to measure MNTs of five bilateral anatomical sites in the epaxial and pelvic musculature of 11 horses referred to physiotherapy because of clinical signs of back pain. Measurements were recorded both before and immediately after traction. A significant difference (P ≤ .05) was identified between mean before and after caudal traction algometry measurements in all described sites. The percentage of MNT increase was highest in the thoracic region (83%) compared with the lumbar (50%) and the pelvic (52.4%) regions. These results support an effect of caudal traction in increasing MNTs in the thoracolumbar and pelvic regions in horses. Further research to determine the clinical effect of this technique is warranted.

A randomised controlled trial of multimodal physiotherapy versus advice for recent onset, painful cervical radiculopathy - the PACeR trial protocol

BACKGROUND

A research gap exists for optimal management of cervical radiculopathy in the first 12 weeks and short term natural history of the condition is somewhat unclear, although thought to be favourable. The primary aim of this assessor blinded, superiority, 2 parallel group randomised controlled trial is to investigate the effects of a 4 week physiotherapy programme (6-8 sessions) of manual therapy, exercise and upper limb neural unloading tape, compared to a control of weekly phone advice; on disability, pain and selected biopsychosocial measures, in acute and sub-acute cervical radiculopathy patients. A secondary aim is to identify whether any baseline variables, symptom duration or group allocation can predict outcome.

METHODS

Participants are recruited from GP referrals in an urban setting, from a neurosurgery non-urgent waiting list and from self-referral through Facebook advertising. Eligible participants (n = 64) are diagnosed with radiculopathy based on a clinical prediction rule and must have symptoms of unilateral, single level, radiculopathy for between 2 and 12 weeks, without having yet received physiotherapy. Random 1:1 group allocation (using variable block sizes), allocation concealment, blinded assessment and intention to treat analysis are being employed. Treatment is provided by clinical specialist physiotherapists in primary and secondary care settings. Outcomes are measured at baseline, 4 (primary endpoint) and 12 weeks. Participants' report of pain, disability and their rating of recovery is also recorded by telephone interview at 6 months. Statistical analysis of between group differences will be performed with ANOVAs and MANOVAs, and multivariable regression analysis will be undertaken to explore predictor variables. Ethical approval for this study has been received from the Beaumont Hospital and Irish College of General Practitioners Research Ethics Committees. The trial is registered at ClinicalTrials.gov (NCT02449200).

DISCUSSION

An internal pilot study to test retention and recruitment strategies led to trial expansion and this is now a multi centre trial involving 5 clinical sites.

TRIAL REGISTRATION

NCT02449200 . Registered 20/05/15.

Correlations among algometry, the visual analogue scale, and the numeric rating scale to assess chronic pelvic pain in women

Objective

To investigate the correlation between the numerical rating scale, visual analogue scale, and pressure threshold by algometry in women with chronic pelvic pain.

Study design

This was a cross-sectional study. We included 47 patients with chronic pelvic pain. All subjects underwent a pain assessment that used three different methods and were divided according to the cause of pain (endometriosis versus non-endometriosis). Moreover, we assessed the agreement between the scales (visual, analogue and algometry) using the intraclass correlation coefficient (ICC).

Results

The ICC for the numeric rating scale and the visual analogue scale regarding pain (0.992), dysmenorrhea (1.00) and dyspareunia (0.996) were strong. The agreement between the scales was excellent (p ≤0.01). The correlation between algometry and the scales showed a moderate and inverse association, and this correlation was statistically significant: as the scores on the numeric rating scale and the visual analogue scale regarding dyspareunia increased, the algometry thresholds decreased.

Conclusions

The assessment of women with chronic pelvic pain should combine pressure algometry and the numeric rating scale or the visual analogue scale, because of their inverse correlations and satisfactory reliability and sensitivity, to make pain assessment less subjective and more accurate.

Training volume is associated with pain sensitivity, but not with endogenous pain modulation, in competitive swimmers

OBJECTIVES

To investigate the association of pain sensitivity and endogenous analgesia capacity, and training volume in a group of competitive swimmers.

DESIGN

An observational multi-center study.

SETTING

Multiple competitive swimming clubs.

PARTICIPANTS

102 healthy competitive swimmers.

MAIN OUTCOME MEASURES

Training volume was estimated using self-reported information. Static and dynamic measures of pain were assessed using pressure pain thresholds (PPTs) and conditioned pain modulation (CPM), the latter as a measure of endogenous pain inhibition. Selected demographic and psychosocial measures were considered as possible confounding factors.

RESULTS

Moderate positive correlations (0.38 < r < 0.44; p < 0.01) exist between self-reported training volume and PPTs at widespread body areas in competitive swimmers. These results were maintained during linear regression analysis while addressing possible confounding factors such as age and selected psychosocial factors. No associations were found between self-reported training volume and conditioned pain modulation (-0.08 < r < 0.06; p > 0.05).

CONCLUSIONS

Self-reported swim training volume is associated with pain sensitivity in competitive swimmers. Swimmers who train more show higher pressure pain thresholds, indicating lower pain sensitivity. Swim training volume is not associated with endogenous nociceptive inhibitory capacity as determined using CPM.

Application of a handheld Pressure Application Measurement device for the characterisation of mechanical nociceptive thresholds in intact pig tails

The assessment of nociceptive thresholds is employed in animals and humans to evaluate changes in sensitivity potentially arising from tissue damage. Its application on the intact pig tail might represent a suitable method to assess changes in nociceptive thresholds arising from tail injury, such as tail docking or tail biting. The Pressure Application Measurement (PAM) device is used here for the first time on the tail of pigs to determine the reliability of the methods and to provide novel data on mechanical nociceptive thresholds (MNT) associated with four different age groups (9, 17, 24 and 32 weeks) and with proximity of the target region to the body of the animal. We recorded an overall acceptable level of intra-individual reliability, with mean values of CV ranging between 30.1 and 32.6%. Across all age groups, the first single measurement of MNT recorded at region 1 (proximal) was significantly higher (P < 0.05) than the following two. This was not observed at tail regions 2 and 3 (more distal). Age had a significant effect (P < 0.05) on the mean thresholds of nociception with increasing age corresponding to higher thresholds. Furthermore, a significant effect of proximity of tail region to the body was observed (P < 0.05), with MNT being higher in the proximal tail region in pigs of 9, 17 and 24 weeks of age. There was also a significant positive correlation (P < 0.05) between mechanical nociceptive thresholds and age/body size of the animals.

To the best of our knowledge, no other investigation of tail nociceptive thresholds has been performed with the PAM device or alternative methods to obtain mechanical nociceptive thresholds in intact tails of pigs of different age/body size. The reliability of the data obtained with the PAM device support its use in the measurement of mechanical nociceptive threshold in pig tails. This methodological approach is possibly suitable for assessing changes in tail stump MNTs after tail injury caused by tail docking and biting.

•

Mechanical nociceptive thresholds were quantified for the first time in pig tails.

•

The PAM device allowed determining anatomical and age-specific thresholds in pigs.

•

A platform for the assessment of painful conditions in pigs is proposed.

Preliminary results in a group of twenty patients]

OBJECTIVES

To study the relationship between the appearance of end-of-stem pain with a preoperative decrease in local bone strength by using the bone microindentation technique. The potential usefulness of pressure algometry in the diagnosis and monitoring of this group of patients is also determined.

MATERIAL AND METHOD

A preliminary intra- and inter-rater correlation study was performed in a group of 50 healthy volunteers in order to validate the algometry technique. A prospective study was then conducted on 20 patients with a mean age of 74 years (range 57-84) undergoing knee prosthetic surgery with use of a cementless tibial stem. Bone microindentation and pressure algometry measurements were made preoperatively, and after one year of follow-up. The statistical analysis was performed using the Intraclass correlation coefficient and the Student t test for paired data.

RESULTS

The intra and inter-rater correlation values were excellent; 0.91 (0.84-0.95) and 0.86 (0.74-0.92), respectively. No significant variations were found in the microindentation (P=.11) or in the pressure algometry (P=.6) values after one year of follow-up. Nevertheless, a significant correlation was observed between the values for pressure algometry and the EVA (P=.002) and functional scale (P=.02) at the end of follow-up.

CONCLUSIONS

Pressure Algometry is a useful tool to evaluate this group of patients. Bone microindentation does not seem to be useful in identifying patients with increased risk of developing tibial end-of-stem pain.

Increased pain sensitivity but normal function of exercise induced analgesia in hip and knee osteoarthritis--treatment effects of neuromuscular exercise and total joint replacement

OBJECTIVE

To assess exercise induced analgesia (EIA) and pain sensitivity in hip and knee osteoarthritis (OA) and to study the effects of neuromuscular exercise and surgery on these parameters.

DESIGN

The dataset consisted of knee (n = 66) and hip (n = 47) OA patients assigned for total joint replacement at Lund University Hospital undergoing pre-operative neuromuscular exercise and 43 matched controls. Sensitivity to pressure pain was assessed by pressure algometry at 10 sites. Subjects were then instructed to perform a standardized static knee extension. Pressure pain thresholds (PPTs) were assessed at the contracting quadriceps muscle (Q) and at the resting deltoid muscle (D) before and during contraction. The relative increase in PPTs during contraction was taken as a measure of localized (Q) or generalized (D) EIA. Patients were assessed at baseline, following on average 12 weeks of neuromuscular exercise and 3 months following surgery.

RESULTS

We found a normal function of EIA in OA patients at baseline. Previous studies have reported beneficial effects of physical exercise on pain modulation in healthy subjects. However, no treatment effects on EIA were seen in OA patients despite the increase in muscle strength following neuromuscular exercise and reduced pain following surgery. Compared to controls, OA patients had increased pain sensitivity and no beneficial effects on pain sensitivity were seen following treatment.

CONCLUSIONS

To our knowledge, this is the first study of EIA in OA patients. Despite increased pain sensitivity, OA patients had a normal function of EIA.

Relating clinical measures of pain with experimentally assessed pain mechanisms in patients with knee osteoarthritis

Background Peripheral and central sensitisation is prominent in knee osteoarthritis (KOA) and could be important for the reduced efficacy in some cases after as well surgery as pharmacological interventions. Although sensitisation is important in KOA it is not known to what degree it contributes to the overall clinical pain problem. The aim was therefore to investigate how much a combination of quantitative pain measures assessing various pain mechanisms (local and spreading hyperalgesia, temporal and spatial summation, descending inhibition) could predict peak pain intensity in patients with KOA. Methods While resting in a comfortable recumbent position the pressure pain thresholds (PPT) in the peripatellar region (eight locations) and at the tibialis anterior muscle (TA) were assessed by handheld pressure algometry, computer-controlled pressure algometry and cuff-algometry in the affected leg of 17 KOA patients without pain or sensory dysfunctions in other regions than the knee. Cuff-algometry was used to detect spatial pain summation of the lower leg. Temporal pain summation was assessed by repeated pressure stimulation on the TA muscle. The conditioning pain modulation (CPM) was evaluated by conditioning tonic arm pain and by PPT from the peripatellar region. The participants rated their peak pain intensity in the previous 24 h using on a 10 cm visual analogue scale. Results A multiple-regression model based on TA pressure pain sensitivity (spreading sensitisation) and temporal pain summation on the lower leg accounted for 55% of the variance in peak pain intensity experienced by the patients (P=0.001). Significant correlations (P< 0.05) were found between PPTs assessed by handheld pressure algometry in the peripatellar region and at TA (R = 0.94), PPTs assessed by computer-controlled pressure algometry and handheld pressure algometry in the peripatellar region (R = 0.71), PPTs assessed by computer-controlled pressure algometry in the peripatellar region and handheld pressure algometry at TA (R = 0.71) and temporal summation at the knee and at TA (R = 0.73). Conclusion Based on the multiple regression model 55% variance of the perceived maximal pain intensity in painful KOA could be explained by the quantitative experimental pain measures reflecting central pain mechanisms (spreading sensitisation, temporal summation). The lack of other correlations between the methods used in assessing pain mechanisms in this study highlights the importance of applying different tests and different pain modalities when assessing the sensitised pain system as different methods add complementary information. Implications Clinical pain intensity can be explained by influences of different central pain mechanisms in KOA. This has implications for pain management in KOA where treatment addressing central pain components may be more important than previously acknowledged.

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

PURPOSE

Pressure algometry is widely used to obtain measures of mechanical pain sensitivity in adults, both in experimental and clinical pain conditions. Only very few studies describe the use of pressure algometry in children. The purpose of this study was to produce reference values of pressure pain thresholds and to determine the intra- and interrater agreement, in order to introduce pressure algometry as a standardized method for the assessment of pain thresholds in children with orthopedic disorders.

METHODS

Pressure pain thresholds were determined at the leg and at the thenar in 50 children aged 4-12 years. All were scheduled for physical examination at the outpatient Orthopedic Clinic at Aarhus University Hospital, Denmark, because of various orthopedic disorders such as clubfoot and Baker's cyst. Pressure pain thresholds were determined by two different raters: 20 children were examined twice by rater 1 (intrarater agreement), and another 20 children were examined by both rater 1 and rater 2 (interrater agreement). An additional ten children were examined once by rater 1 to increase the number of children used to determine the reference values.

RESULTS

The pressure pain threshold was 183.1 kPa (mean, SD: 90.7) at the leg and 179.1 kPa (mean, SD: 97.4 kPa) at the thenar (n = 50). Pressure pain thresholds were similar in boys (n = 27) and girls (n = 23). Also, pressure pain thresholds were not affected by age. Bland-Altman plots showed excellent intrarater agreement and satisfactory interrater agreement.

CONCLUSION

Pressure algometry has excellent intrarater agreement and satisfactory interrater agreement. Pressure algometry was well-tolerated even by very young children. The method deserves more widespread use both in clinical and experimental settings.