Identifying Pain Generators and Potentiators of Residual Complaints Following Lumbar Discectomy

Terminated

• Conditions: Lumbar Radiculopathy; Central Sensitisation
• Interventions: Procedure: Lumbar discectomy

• Registration Number: NCT05022251
• Lead Sponsor: University Ghent

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2021-05-12
• Study First Submitted QC: 2021-08-19
• Study First Posted: 2021-08-26
• Study Start: 2021-10-01
• Primary Completion: 2023-10-31
• Study Completion: 2023-10-31
• Status Verified: 2023-12
• Last Update Submitted: 2023-12-14
• Last Update Posted: 2023-12-20

Recruitment & Eligibility

• Status: TERMINATED
• Sex: All
• Target Recruitment: 1

Inclusion Criteria

• Dutch speaking
• Body mass index below 35kg/m²
• Lumbar radiculopathy patients, classified as ASA I to II without any symptoms of spinal cord compression (i.e. bilateral leg pain), who are scheduled for a first-time, single-level, unilateral lumbar discectomy
• Healthy, pain-free controls (score 0 on a visual analogue scale from 0 to 100)

Exclusion Criteria

• Female participants will be excluded if pregnant, lactating or <1 year postnatal
• Having (a history) of severe medical disorders either respiratory (e.g. cystic fibrosis), orthopedic (e.g. whiplash trauma), neurologic (e.g. cerebrovascular incident), cardiovascular (e.g. severe hypertension), endocrinological (e.g. diabetes), psychiatric (e.g. post-traumatic stress disorder
• Having a history of spinal surgery (e.g. discectomy), spinal traumata (e.g. vertebral fracture) or severe spinal deformities (e.g. spondylolisthesis)
• Having a pacemaker or defibrillator
• Healthy controls will be excluded if having suffered low back pain in the preceding year of score 2 or higher on the visual analog scale and which limited their activities of daily living or for which they consulted a (para)medic.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Lumbar radiculopathy	Lumbar discectomy	Lumbar radiculopathy patients (n=122), classified as ASA I to II without any symptoms of spinal cord compression (i.e. bilateral leg pain), who are scheduled for a first-time, single-level, unilateral lumbar discectomy.

Primary Outcome Measures

Name	Time	Method
Quantitative sensory testing (QST) - temporal summation of mechanical stimuli	Change from baseline (T1) and 3 months after surgery (T2)	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.
Quantitative sensory testing (QST) - electrical pain threshold	Change from baseline (T1) at 3 months after surgery (T2)	Determination of sensory pain threshold in response to electrical stimuli which are delivered transcutaneously over the n. suralis and n. medianus, recorded in mA.
Quantitative sensory testing (QST) - thermal pain threshold	Change from baseline (T1) at 3 months after surgery (T2)	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
Quantitative sensory testing (QST) - mechanical pain threshold	Change from baseline (T1) at 3 months after surgery (T2)	Determination of mechanical pain threshold, assessed using pinprick stimulators, recorded in mN
Quantitative sensory testing (QST) - temporal summation of electrical stimuli	Change from baseline (T1) and 3 months after surgery (T2)	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.
Quantitative sensory testing - conditioned pain modulation	Change from baseline (T1) and 3 months after surgery (T2)	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.
Quantitative sensory testing (QST) - electrical detection threshold	Change from baseline (T1) at 3 months after surgery (T2)	Determination of sensory detection thresholds in response to electrical stimuli which are delivered transcutaneously over the n. suralis and n. medianus, recorded in mA.
Quantitative sensory testing (QST) - spinal hyperexcitability	Change from baseline (T1) and 3 months after surgery (T2)	Determination of spinal hyperexcitability using the nociceptive flexion reflex (NFR; sensitization of spinal cord neurons), recorded in mA
Quantitative sensory testing (QST) - thermal detection threshold	Change from baseline (T1) at 3 months after surgery (T2)	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
Quantitative sensory testing (QST) - discrimination between thermal stimuli	Change from baseline (T1) at 3 months after surgery (T2)	Determination of the number of paradoxical heat sensations in response to alternating cold and warm stimuli delivered to the skin using a thermode.
Quantitative sensory testing (QST) - tactile detection threshold	Change from baseline (T1) at 3 months after surgery (T2)	Determination of tactile detection threshold, assessed using Von Frey monofilaments, recorded in mN
Quantitative sensory testing (QST) - sensitivity to pressure stimuli	Change from baseline (T1) at 3 months after surgery (T2)	Determination of pressure pain threshold, assessed using pressure algometry, recorded in kg
Quantitative sensory testing (QST) - temporal summation of spinal hyperexcitability	Change from baseline (T1) and 3 months after surgery (T2)	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)

Secondary Outcome Measures

Name	Time	Method
Tampa scale for kinesiophobia	3 months after surgery (T2)	Self-report measure assessing fear of movement
Brief Illness Perception Questionnaire	3 months after surgery (T2)	Self-report measure evaluating illness perceptions
Douleur Neuropathique 4 Questionnaire	3 months after surgery (T2)	Clinician administered questionnaire for evaluation of signs and symptoms associated with neuropathic pain
Central sensitization inventory	3 months after surgery (T2)	Self-report measure of signs and symptoms associated with central sensitization
Patient-reported outcomes measurement information system	3 months after surgery (T2)	Self-report measure of health-related domains including: * physical functioning; * anxiety; * depression; * fatigue; * sleep disruption; * participation in social activities; * pain interference
Pain vigilance and awareness questionnaire	3 months after surgery (T2)	Self-report measure assessing preoccupation with and attention to pain
Pain catastrophizing scale	3 months after surgery (T2)	Self-report measure of pain perceptions and cognitions
Oswestry disability index	3 months after surgery (T2)	Self-report measure evaluating low back pain related disability
International physical activity questionnaire	3 months after surgery (T2)	Self-report measure of physical activity in preceeding 7 days
Pain Coping Inventory	3 months after surgery (T2)	Self-report measure assessing pain coping strategies

Trial Locations

Locations (1)

Ghent University (Hospital); 🇧🇪 Ghent, Belgium