Lumbar discectomy (i.e. surgically removing a hernia) is frequently performed in Belgium to treat lumbar radiculopathy. Every year \>12,000 interventions are performed with variable long-term results. The treatment success of this procedure varies and up to 41% of the patients report post-operative persistent pain complaints, and consequently suffer from failed back surgery syndrome (FBSS). Chronic complaints in FBSS following lumbar discectomy are usually treated with symptomatic interventions (including painkillers, neuromodulation, etc), rather than from a biopsychosocial perspective. In order to develop a focused and effective treatment strategy, it is crucial to first gain insight into how persons with persistent complaints after lumbar discectomy differ from those without persistent symptoms. Different known contributing factors entail type of surgery, muscle and psychosocial impairments. Although in scientific and clinical literature it is assumed that dysfunctional pain processing also plays an important mechanistic role in FBSS, there is a lack of research to support this. However, this knowledge is crucial to depict the full mechanistic picture of pain generators and potentiators in FBSS. Therefore, we will examine whether residual complaints persisting following lumbar discectomy can be accounted for by underlying dysfunctional pain processing and whether a clinical classification algorithm can be used to identify the predominant pain mechanism in these patients.
Study Type
OBSERVATIONAL
Enrollment
1
surgically removing a hernia
Ghent University (Hospital)
Ghent, Belgium
Quantitative sensory testing (QST) - electrical detection threshold
Determination of sensory detection thresholds in response to electrical stimuli which are delivered transcutaneously over the n. suralis and n. medianus, recorded in mA.
Time frame: Change from baseline (T1) at 3 months after surgery (T2)
Quantitative sensory testing (QST) - electrical pain threshold
Determination of sensory pain threshold in response to electrical stimuli which are delivered transcutaneously over the n. suralis and n. medianus, recorded in mA.
Time frame: Change from baseline (T1) at 3 months after surgery (T2)
Quantitative sensory testing (QST) - thermal detection threshold
Determination of sensory detection thresholds in response to thermal stimuli which are delivered to the skin using a thermode, recorded in °C: * cold detection threshold * warmth detection threshold
Time frame: Change from baseline (T1) at 3 months after surgery (T2)
Quantitative sensory testing (QST) - thermal pain threshold
Determination of sensory pain thresholds in response to thermal stimuli which are delivered to the skin using a thermode, recorded in °C: * cold pain threshold * heat pain threshold
Time frame: Change from baseline (T1) at 3 months after surgery (T2)
Quantitative sensory testing (QST) - discrimination between thermal stimuli
Determination of the number of paradoxical heat sensations in response to alternating cold and warm stimuli delivered to the skin using a thermode.
Time frame: Change from baseline (T1) at 3 months after surgery (T2)
Quantitative sensory testing (QST) - tactile detection threshold
Determination of tactile detection threshold, assessed using Von Frey monofilaments, recorded in mN
Time frame: Change from baseline (T1) at 3 months after surgery (T2)
Quantitative sensory testing (QST) - mechanical pain threshold
Determination of mechanical pain threshold, assessed using pinprick stimulators, recorded in mN
Time frame: Change from baseline (T1) at 3 months after surgery (T2)
Quantitative sensory testing (QST) - sensitivity to pressure stimuli
Determination of pressure pain threshold, assessed using pressure algometry, recorded in kg
Time frame: Change from baseline (T1) at 3 months after surgery (T2)
Quantitative sensory testing (QST) - temporal summation of electrical stimuli
Determination of temporal summation in response to electrical stimuli delivered transcutaneously over the skin of the n. suralis and n. medianus. The numerical pain rating in response to these stimuli (range 0 - 100) will be recorded.
Time frame: Change from baseline (T1) and 3 months after surgery (T2)
Quantitative sensory testing (QST) - temporal summation of mechanical stimuli
Determination of temporal summation in response to mechanical stimuli delivered using a 256mN pinprick stimulator. The numerical pain rating in response to these stimuli (range 0 - 100) will be recorded.
Time frame: Change from baseline (T1) and 3 months after surgery (T2)
Quantitative sensory testing (QST) - spinal hyperexcitability
Determination of spinal hyperexcitability using the nociceptive flexion reflex (NFR; sensitization of spinal cord neurons), recorded in mA
Time frame: Change from baseline (T1) and 3 months after surgery (T2)
Quantitative sensory testing (QST) - temporal summation of spinal hyperexcitability
Determination of temporal summation of the nociceptive flexion reflex (NFR; sensitization of spinal cord neurons), recorded using a numeric pain rating scale (range 0 - 100)
Time frame: Change from baseline (T1) and 3 months after surgery (T2)
Quantitative sensory testing - conditioned pain modulation
Determination of condition pain modulation (aka. pain inhibits pain) by means of a heterotopic noxious counterstimulation paradigm. Test stimuli comprise of pressure pain threshold assessments and application of a heat stimulus (using a thermode) corresponding to a temperature eliciting a visual analog scale rating of 5/10. Test stimuli will be applied before, during and after the conditioning stimulus which is the immersion of the hand in a hot circulating water bath of 45.5°C.
Time frame: Change from baseline (T1) and 3 months after surgery (T2)
Central sensitization inventory
Self-report measure of signs and symptoms associated with central sensitization
Time frame: Baseline (T1)
Central sensitization inventory
Self-report measure of signs and symptoms associated with central sensitization
Time frame: 3 months after surgery (T2)
Douleur Neuropathique 4 Questionnaire
Clinician administered questionnaire for evaluation of signs and symptoms associated with neuropathic pain
Time frame: Baseline (T1)
Douleur Neuropathique 4 Questionnaire
Clinician administered questionnaire for evaluation of signs and symptoms associated with neuropathic pain
Time frame: 3 months after surgery (T2)
Pain catastrophizing scale
Self-report measure of pain perceptions and cognitions
Time frame: Baseline (T1)
Pain catastrophizing scale
Self-report measure of pain perceptions and cognitions
Time frame: 3 months after surgery (T2)
Pain vigilance and awareness questionnaire
Self-report measure assessing preoccupation with and attention to pain
Time frame: Baseline (T1)
Pain vigilance and awareness questionnaire
Self-report measure assessing preoccupation with and attention to pain
Time frame: 3 months after surgery (T2)
Oswestry disability index
Self-report measure evaluating low back pain related disability
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Time frame: Baseline (T1)
Oswestry disability index
Self-report measure evaluating low back pain related disability
Time frame: 3 months after surgery (T2)
Tampa scale for kinesiophobia
Self-report measure assessing fear of movement
Time frame: Baseline (T1)
Tampa scale for kinesiophobia
Self-report measure assessing fear of movement
Time frame: 3 months after surgery (T2)
International physical activity questionnaire
Self-report measure of physical activity in preceeding 7 days
Time frame: Baseline (T1)
International physical activity questionnaire
Self-report measure of physical activity in preceeding 7 days
Time frame: 3 months after surgery (T2)
Patient-reported outcomes measurement information system
Self-report measure of health-related domains including: * physical functioning * anxiety * depression * fatigue * sleep disruption * participation in social activities * pain interference
Time frame: Baseline (T1)
Patient-reported outcomes measurement information system
Self-report measure of health-related domains including: * physical functioning * anxiety * depression * fatigue * sleep disruption * participation in social activities * pain interference
Time frame: 3 months after surgery (T2)
Brief Illness Perception Questionnaire
Self-report measure evaluating illness perceptions
Time frame: Baseline (T1)
Brief Illness Perception Questionnaire
Self-report measure evaluating illness perceptions
Time frame: 3 months after surgery (T2)
Pain Coping Inventory
Self-report measure assessing pain coping strategies
Time frame: Baseline (T1)
Pain Coping Inventory
Self-report measure assessing pain coping strategies
Time frame: 3 months after surgery (T2)