Clinical trial NCT03021278: Tactile Acuity in Experimentally Induced Acute Low Back Pain
Official title: Lumbar Tactile Acuity in Experimentally Induced Acute Low Back Pain
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Acute Pain
Low Back Pain
Keywords: Tactile acuity
Chronic pain
Two-point discrimination
Point-to-point test
Two-point estimation
Body image
Lead sponsor: The Jerzy Kukuczka Academy of Physical Education in Katowice
Sponsor class: OTHER
Collaborators: name: Universitätsklinikum Hamburg-Eppendorf
First posted: 2017-01-13
Enrollment: 57
Sex: MALE
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: The purpose of this study is to determine whether experimentally induced acute low back pain might lead to alteration in lumbar tactile acuity measured in region affected by pain compared to pain-free side and pain-free controls.

Detailed description: Healthy male participants will be recruited at the Academy of Physical Education in Katowice. Each participant will be assessed only once. All participants will be asked to provide written informed consent for participation prior to the experimental procedure and will be naïve to the experimental hypothesis. The plan for this research project has been previously approved by the local bioethical committee.

Between-subject (real-injection, sham-injection and control group) and within-subject (assessment 1 versus assessment 2 and 3) design will be used for the purpose of this experiment. After the screening procedure and preparation phase, participants will be randomly assigned to one of three groups: control, saline injection or sham-injection. Groups will differ only in terms of the specific manipulation: the experimental group will receive intra-muscular saline injection, the sham-injection group will be stimulated by pinprick sensation produced by a PinPrick device. No manipulation will take place in the control group allowing to control for the learning effect. In fact, participants will be informed that the study includes only two branches so they can be assigned either to the group with pain evoked as a result of an injection or to the control group without any noxious stimuli. Not revealing the sham-injection condition will allow for comparison between nociceptive (injection) and non-nociceptive (sham-injection) condition.

Because no previous studies have investigated tactile acuity changes in acute low back pain, the sample size calculation was based on the data from our own systematic review and meta-analysis (Adamczyk et al., under review) and previous cross-sectional data among healthy controls (Adamczyk et al., 2016). Based on reported mean difference of 9.49mm between chronic low back pain patients and healthy controls and standard deviation of 9.90mm, a total sample size of 57 participants (19 per group) is required to detect a significant effect. Power calculation was performed for specific planned-comparison tests that were described in detailed under 'statistical analysis' section below. Calculation was performed in G\*Power (G\*Power 3.1.9.2 statistical software) with the alpha level set at =0.05 and 80% power.

Baseline differences in descriptive statistics will be analysed by one-way analysis of variance (ANOVA) with 'group' as the between-subject factor. Further statistical comparisons will be performed using a repeated-measures ANOVA design, with 'group' (real-injection, sham-injection, and control group) as between-subject factor and repeated measures (assessment 1, 2 and 3) as a within-subject factor. In order to test hypothesis on tactile acuity alteration during pain induction, F-tests will be followed by planned comparisons on data from assessment 1 versus assessment 2 in experimental group. To determine whether the magnitude of tactile acuity alteration has differed between the groups, planned comparisons will be performed on the difference in tactile acuity (assessment 1 vs. assessment 2) between real-injection and sham-injection group and between real-injection and control group. Bonferroni correction will be used for multiple planned comparisons. Forward, stepwise multiple regression will be performed to determine the degree to which tactile acuity change is predicted by either pain intensity or the size of its distribution. All the analyses will be conducted using the STATISTICA data analysis software, version 12 (StatSoft Inc., Tulsa, OK, USA). The level of significance will be set at p \< 0.05.

Eligibility criteria: Inclusion Criteria:

* Only participants with similar mechanical detection threshold (MDT) on both sides of the spine will be included.

Exclusion Criteria:

* sex: female
* age \< 18 or \> 35 years
* laterality: left-handed
* current pain experience
* episodes of back pain lasting more than 24 hours within the previous one-month period
* history of chronic pain, i.e. pain lasting more than one-month
* comorbidities affecting the nervous system
* cardio-vascular diseases
* psychiatric illnesses
* any disease requiring systematic drug consumption.
* diagnosed hypersensitive reaction to saline solution

Primary outcomes:
measure: Lumbar tactile acuity measured by two-point discrimination test (TPD).
timeFrame: Measured an average 3 minutes after manipulation (e.g. saline injection).
Secondary outcomes:
measure: Pain intensity measured behaviourally on a Numerical Rating Scale (NRS).
timeFrame: Pain intensity will be measured just after saline/sham injection and every 30 seconds after this time point up until 12 minutes.
measure: Distribution of pain measured by estimating the diameter of the circle representing area affected by pain. Greater circle (diameter) will refer to the greater distribution of pain (larger body surface affected).
timeFrame: Pain distribution will be measured just after saline/sham injection and every 30 seconds after this time point up until 12 minutes.
measure: Fear of pain measured on a Numerical Rating Scale (NRS).
timeFrame: Fear of pain measured only at baseline
measure: Lumbar tactile acuity measured by point-to-point test (PTP).
timeFrame: PTP measured at baseline (1), an average 3 minutes after manipulation (2) (e.g. saline injection) and 12 minutes after manipulation (3)
measure: Lumbar tactile acuity measured by two-point estimation test (TPE)
timeFrame: PTP measured at baseline (1), an average 3 minutes after manipulation (2) (e.g. saline injection) and 12 minutes after manipulation (3)
Other outcomes:
measure: Fear of Pain Questionnaire (FPQ-III).
timeFrame: Measured only at baseline
measure: Pain Catastrophizing Scale (PCS).
timeFrame: Measured only at baseline
Locations:
city: Katowice
country: Poland
facility: The Jerzy Kukuczka Academy of Physical Education
Study officials:
affiliation: The Jerzy Kukuczka Academy of Physical Education
name: Wacław M Adamczyk, Msc
role: PRINCIPAL_INVESTIGATOR
References:
citation: Adamczyk W, Slugocka A, Saulicz O, Saulicz E. The point-to-point test: A new diagnostic tool for measuring lumbar tactile acuity? Inter and intra-examiner reliability study of pain-free subjects. Man Ther. 2016 Apr;22:220-6. doi: 10.1016/j.math.2015.12.012. Epub 2016 Jan 2.
citation: Catley MJ, O'Connell NE, Berryman C, Ayhan FF, Moseley GL. Is tactile acuity altered in people with chronic pain? a systematic review and meta-analysis. J Pain. 2014 Oct;15(10):985-1000. doi: 10.1016/j.jpain.2014.06.009. Epub 2014 Jun 28.
citation: Tsao H, Tucker KJ, Coppieters MW, Hodges PW. Experimentally induced low back pain from hypertonic saline injections into lumbar interspinous ligament and erector spinae muscle. Pain. 2010 Jul;150(1):167-172. doi: 10.1016/j.pain.2010.04.023. Epub 2010 May 26.
citation: Wand BM, Di Pietro F, George P, O'Connell NE. Tactile thresholds are preserved yet complex sensory function is impaired over the lumbar spine of chronic non-specific low back pain patients: a preliminary investigation. Physiotherapy. 2010 Dec;96(4):317-23. doi: 10.1016/j.physio.2010.02.005.
citation: Adamczyk WM, Saulicz O, Saulicz E, Luedtke K. Tactile acuity (dys)function in acute nociceptive low back pain: a double-blind experiment. Pain. 2018 Mar;159(3):427-436. doi: 10.1097/j.pain.0000000000001110.