Identifying Pain Generators and Potentiators of Residual Complaints Following Lumbar Discectomy (DISC-PAIN)

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 Overview

• Status: Terminated
• Conditions: Lumbar Radiculopathy; Central Sensitisation
• Intervention / Treatment: Procedure: Lumbar discectomy

• Study Type: Observational
• Enrollment (Actual): 1

Contacts and Locations

Study Locations

• Belgium
  • Ghent, Belgium
    • Ghent University (Hospital)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Lumbar radiculopathy patients scheduled for first-time, single level, unilateral lumbar discectomy.

Sex, age, and BMI matched healthy controls.

Description

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 Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Lumbar radiculopathy; 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.	Procedure: Lumbar discectomy; surgically removing a hernia
Healthy controls; Sex, age, and BMI-matched healthy, pain-free control subjects (n=122) will be recruited for study participation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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	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	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.	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	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	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	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.	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.	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	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)	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.	Change from baseline (T1) and 3 months after surgery (T2)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Central sensitization inventory	Self-report measure of signs and symptoms associated with central sensitization	Baseline (T1)
Central sensitization inventory	Self-report measure of signs and symptoms associated with central sensitization	3 months after surgery (T2)
Douleur Neuropathique 4 Questionnaire	Clinician administered questionnaire for evaluation of signs and symptoms associated with neuropathic pain	Baseline (T1)
Douleur Neuropathique 4 Questionnaire	Clinician administered questionnaire for evaluation of signs and symptoms associated with neuropathic pain	3 months after surgery (T2)
Pain catastrophizing scale	Self-report measure of pain perceptions and cognitions	Baseline (T1)
Pain catastrophizing scale	Self-report measure of pain perceptions and cognitions	3 months after surgery (T2)
Pain vigilance and awareness questionnaire	Self-report measure assessing preoccupation with and attention to pain	Baseline (T1)
Pain vigilance and awareness questionnaire	Self-report measure assessing preoccupation with and attention to pain	3 months after surgery (T2)
Oswestry disability index	Self-report measure evaluating low back pain related disability	Baseline (T1)
Oswestry disability index	Self-report measure evaluating low back pain related disability	3 months after surgery (T2)
Tampa scale for kinesiophobia	Self-report measure assessing fear of movement	Baseline (T1)
Tampa scale for kinesiophobia	Self-report measure assessing fear of movement	3 months after surgery (T2)
International physical activity questionnaire	Self-report measure of physical activity in preceeding 7 days	Baseline (T1)
International physical activity questionnaire	Self-report measure of physical activity in preceeding 7 days	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	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	3 months after surgery (T2)
Brief Illness Perception Questionnaire	Self-report measure evaluating illness perceptions	Baseline (T1)
Brief Illness Perception Questionnaire	Self-report measure evaluating illness perceptions	3 months after surgery (T2)
Pain Coping Inventory	Self-report measure assessing pain coping strategies	Baseline (T1)
Pain Coping Inventory	Self-report measure assessing pain coping strategies	3 months after surgery (T2)

Collaborators and Investigators

• Sponsor: University Ghent
• Collaborators: Research Foundation Flanders
• Investigators: Study Director: Jessica Van Oosterwijck, PhD, Ghent University; Research Foundation Flanders

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2021
• Primary Completion (Actual): October 31, 2023
• Study Completion (Actual): October 31, 2023

Study Registration Dates

• First Submitted: May 12, 2021
• First Submitted That Met QC Criteria: August 19, 2021
• First Posted (Actual): August 26, 2021

Study Record Updates

• Last Update Posted (Estimated): December 20, 2023
• Last Update Submitted That Met QC Criteria: December 14, 2023
• Last Verified: December 1, 2023

More Information

Terms related to this study

• Keywords: central sensitization; discectomy; lumbar radiculopathy
• Additional Relevant MeSH Terms: Nervous System Diseases; Neuromuscular Diseases; Peripheral Nervous System Diseases; Radiculopathy
• Other Study ID Numbers: BC-08041; 3F014119 (Other Grant/Funding Number: Research Foundation - Flanders (FWO))

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No