Pressure pain threshold and temporal summation in adults with episodic and persistent low back pain trajectories: a secondary analysis at baseline and after lumbar manipulation or sham

Abstract

Background: People with chronic low back pain (LBP) typically have increased pain sensitivity compared to healthy controls, however its unknown if pain sensitivity differs based on LBP trajectory at baseline or after manual therapy interventions. We aimed to compare baseline pressure pain threshold (PPT) and temporal summation (TS) between people without LBP, with episodic LBP, and with persistent LBP, and to compare changes over time in PPT and TS after a lumbar spinal manipulation or sham manipulation in those with LBP. Methods: Participants were aged 18-59, with or without LBP. Those with LBP were categorised as having either episodic or persistent LBP. PPT and TS were tested at baseline. LBP participants then received a lumbar spinal manipulation or sham, after which PPT and TS were re-tested three times over 30 min. Generalised linear mixed models were used to analyse data. Results: One hundred participants (49 female) were included and analysed. There were 20 non-LBP participants (mean age 31 yrs), 23 episodic LBP (mean age 35 yrs), and 57 persistent LBP (mean age 37 yrs). There were no significant differences in PPT or TS between groups at baseline. There was a non-significant pattern of lower PPT (higher sensitivity) from the non-LBP group to the persistent LBP group at baseline, and high variability. Changes in PPT and TS after the interventions did not differ between the two LBP groups. Discussion: We found no differences between people with no LBP, episodic LBP, or persistent LBP in baseline PPT or TS. Changes in PPT and TS following a lumbar manual therapy intervention do not appear to differ between LBP trajectories. Trial registration: The trial was prospectively registered with ANZCTR (ACTRN12617001094369).

Immediate effects of spinal manipulation on painful sensitivity and postural stability in patients with chronic nonspecific low back pain: study protocol for a controlled randomised clinical trial

“…Spine manipulation affects the regional pressure pain threshold [ 17 ]. However, the pressure pain threshold did not alter immediately after spinal manipulation in patients with LBP in a previous study [ 18 ]. Postural stability appears impaired in individuals with nonspecific cLBP [ 19 – 23 ].…”

“…The patient will be positioned in lateral decubitus with the target side up, knee flexed, and lower hip extended; the physiotherapist will stabilise the shoulder with the cephalic hand and the thigh with his leg and make manual contact with the caudal hand over the process nipple on the upper side of the vertebra to be manipulated with the hypothenar region of the caudal hand. The manipulation will be performed with a passive rotation movement at high speed and low amplitude in the posteroanterior direction in association with the fall of the applicator body [ 18 , 32 ]. The intervention will be carried out in a single moment.…”

“…The participant’s spine will be kept in a neutral position and 90° of hip flexion. The applicator will perform a slow, smooth, and unspecific impulse associated with a small fall of the body [ 15 , 18 ]. The simulated technique will be carried out bilaterally for two times, starting from the symptomatic side.…”

“…The sample size calculation was performed a priori in the software G * Power version 3.1 (Heinrich-Heine-Universität, Düsseldorf, Germany) to determine a sufficient sample size. According to a model used previously [ 18 ] in individuals with LBP to detect a minimum difference of 15% (effect size of 0.64) in the low-pressure pain threshold, the statistical power of 80%, and an alpha of 0.05 in a two-way analysis of variance (ANOVA) repeated measures, the estimated sample size was 40 patients per group. A total of 80 participants will be included in the present study.…”

A novel metric of reliability in pressure pain threshold measurement

“…Participants completed a brief questionnaire, which included demographic data, health status, current medication intake and whether they were experiencing any pain at all. An explanation and demonstration of testing procedures were given to participants prior to testing; one practice PPT test on the forearm was provided to familiarise participants with the testing procedure and to ensure recognition of a painful pressure stimulus 22 . Participants were then asked to lie prone on a padded clinical plinth with a facial breathing hole (Akron, ArjoHuntleigh, UK), at which point the two testing sites (bilateral paraspinal regions at the level of L4/5, 2 cm from the midline) 5 were marked by the rater with a semi-permanent surgical skin-marking pen (Schuco Ltd, UK).…”