An interventional study of Selective Nerve Root Block and Sham Procedure in Lumbar Disc Herniation, Lumbar Radiculopathy and Lumbar Disc Herniation With Radiculopathy, sponsored by Karolinska Institutet. Not yet recruiting at 2 sites in Sweden. Open to participants aged 18 Years to 66 Years. Per ClinicalTrials.gov, last updated 2026-10-26.
Sponsored by Karolinska Institutet · Not applicable, Interventional, and Treatment
The SELDISC trial will investigate whether a selective nerve root block can reduce the need for surgery in adults with a herniated disc in the lower back. A herniated disc can irritate a nerve and cause pain that travels down the leg. A nerve root block delivers a local anaesthetic and a corticosteroid near the affected nerve to relieve pain and inflammation.
The study will include 262 adults aged 18-66 years who have persistent leg symptoms despite non-surgical treatment and have been assessed by a spine surgeon as eligible for surgery.
Participants will be randomly assigned to receive either a selective nerve root block or a sham procedure that mimics the treatment without delivering the active medication near the nerve. Each participant will have an equal chance of receiving either procedure. Participants and the study staff assessing their outcomes will not know which procedure was given. The radiologist performing the procedure will know the allocation.
The main question is whether fewer participants in the nerve root block group undergo surgery within 12 months after randomisation. The study will also compare pain, disability, quality of life, time to surgery, medication use, sick leave, healthcare use and adverse events between the groups.
Selective nerve root blocks are used to treat radicular pain associated with lumbar disc herniation. However, their ability to reduce subsequent surgery in patients already considered eligible for surgical treatment remains uncertain. SELDISC will evaluate whether the therapeutic effect of a selective nerve root block exceeds the contextual and procedural effects of a sham intervention.
The trial uses multicentre recruitment with study procedures performed at the Department of Neuroradiology, Karolinska University Hospital, Sweden. Eligible patients will be identified through clinical assessment, review of magnetic resonance imaging and confirmation of surgical candidacy. Following informed consent and baseline assessments, participants will undergo randomisation using a secure web-based system. Allocation concealment will be maintained through a computer-generated sequence with variable block sizes, stratified by recruitment centre and age. Participants will be offered an appointment for the allocated procedure within 72 hours of enrolment.
The sham procedure is designed to reproduce the experience of the active procedure, including preparation, superficial local anaesthesia and image-guided needle placement, without administering a therapeutic injection near the nerve root. The neuroradiologist performing the procedure will know the treatment allocation but will not participate in subsequent clinical care or outcome assessment. Participants, treating surgeons and outcome assessors will remain blinded.
Clinical information and patient-reported outcomes will be collected prospectively and recorded in an electronic study database. Data from medical records and the Swedish Spine Register (Swespine) will supplement study assessments. The economic evaluation will compare costs and quality-adjusted life years between the treatment groups.
Eligible patients who decline randomisation may be followed through Swespine as a separate observational cohort to assess the representativeness of the randomised population. This cohort will not form part of the randomised treatment comparison.
491 studies on the registry are indexed under Intervertebral Disc Displacement; 104 are open to participants now.
This study's planned enrollment of 262 is above the median of 64 across 353 interventional studies indexed under Intervertebral Disc Displacement.
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Age ≥18 years and \<67 years at the time of consent.
MRI-verified single-level lumbar disc herniation corresponding to clinical symptoms.
Radiculopathy with leg-dominant pain consistent with the affected nerve root.
Failure of conservative treatment (e.g., physiotherapy, analgesics, activity modification) for at least 6 weeks, with surgery considered appropriate.
Duration of symptoms less than 12 months.
Deemed a candidate for lumbar disc surgery by the treating surgeon.
Ability to provide written informed consent and comply with study procedures.
Exclusion criteria:
Previous lumbar spine surgery or other lumbar intervention.
Multi-level disc herniations with an unclear symptomatic level.
Progressive or severe neurological deficit requiring urgent surgery (e.g., cauda equina syndrome, significant motor deficit).
Serious spinal pathology other than disc herniation (e.g., infection, tumour, fracture, inflammatory disease, lumbar idiopathic scoliosis, degenerative deformity).
Relevant systemic comorbidities that increase procedural risk or confound outcomes, including:
Uncontrolled cardiovascular, pulmonary or metabolic disease.
Immunosuppressive therapy or systemic inflammatory disorders.
Psychiatric illness or cognitive impairment interfering with study participation.
Neurological disorders such as Parkinson's disease, multiple sclerosis or polyneuropathy.
Contraindications to injection therapy, including:
Uncontrolled coagulopathy or ongoing anticoagulation that cannot be safely reversed.
Local skin infection or systemic infection.
Known allergy to study medications (local anaesthetic, corticosteroid or contrast agent).
Pregnancy or breastfeeding.
Inability to understand the Swedish language.
Lack of a Swedish personal identification number.
Participants will receive a fluoroscopy-guided selective nerve root block at the affected lumbar nerve root, with injection of a local anaesthetic and a corticosteroid.
Procedure: Selective Nerve Root Block
Participants will undergo a sham procedure that reproduces the preparation, superficial local anaesthesia and image-guided needle placement of the active intervention, without administering any injectate near the nerve root.
Procedure: Sham Procedure
Fluoroscopy-guided needle placement at the affected lumbar nerve root, followed by contrast administration to confirm needle position and injection of a local anaesthetic and a depot corticosteroid.
Superficial local anaesthesia and fluoroscopy-guided needle placement to mimic a selective nerve root block, without contrast or therapeutic injectate administration near the nerve root.
Proportion of participants undergoing lumbar disc surgery
Proportion of participants who undergo surgery for the index lumbar disc herniation within 12 months after randomisation. The outcome is recorded for each participant as yes or no.
Time frame: Within 12 months after randomisation
Time to lumbar disc surgery
Number of days from randomisation to the first surgery for the index lumbar disc herniation. Participants without surgery will be censored at their last follow-up or at 365 days, whichever occurs first.
Time frame: From randomisation to 12 months
Leg pain intensity measured using the Visual Analogue Scale
Leg pain intensity measured using a Visual Analogue Scale (VAS) ranging from 0 to 100 mm, with higher scores indicating greater pain. The prespecified secondary comparison is at 12 months after randomisation. Earlier measurements will be used for descriptive and exploratory analyses.
Time frame: Baseline; 2 days, 2 weeks, 6 weeks, 3 months and 12 months after randomisation
Back pain intensity measured using the Visual Analogue Scale
Back pain intensity measured using a Visual Analogue Scale (VAS) ranging from 0 to 100 mm, with higher scores indicating greater pain. The prespecified secondary comparison is at 12 months after randomisation. Earlier measurements will be used for descriptive and exploratory analyses.
Time frame: Baseline; 2 days, 2 weeks, 6 weeks, 3 months and 12 months after randomisation
Leg pain intensity measured using the Numeric Rating Scale
Leg pain intensity measured using a Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). The prespecified secondary comparison is at 12 months after randomisation. Earlier measurements will be used for descriptive and exploratory analyses.
Time frame: Baseline; 2 days, 2 weeks, 6 weeks, 3 months and 12 months after randomisation
Back pain intensity measured using the Numeric Rating Scale
Back pain intensity measured using a Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). The prespecified secondary comparison is at 12 months after randomisation. Earlier measurements will be used for descriptive and exploratory analyses.
Time frame: Baseline; 2 days, 2 weeks, 6 weeks, 3 months and 12 months after randomisation
Oswestry Disability Index
Disability measured using the Oswestry Disability Index (ODI), version 2.0. Scores range from 0 to 100, with higher scores indicating greater disability. The prespecified secondary comparison is at 12 months after randomisation. Earlier measurements will be used for descriptive and exploratory analyses.
Time frame: Baseline; 2 days, 2 weeks, 6 weeks, 3 months and 12 months after randomisation
Health-related quality of life measured using the EQ-5D-3L index
Health-related quality of life measured using the EQ-5D-3L descriptive system and converted to an index using the selected value set. Higher index values indicate better health; 1 represents full health, and negative values represent health states valued below death. The prespecified secondary comparison is at 12 months after randomisation. Earlier measurements will be used for descriptive and exploratory analyses.
Time frame: Baseline; 2 days, 2 weeks, 6 weeks, 3 months and 12 months after randomisation
Self-rated health measured using the EQ-VAS
EQ-VAS, ranging from 0 (worst imaginable health) to 100 (best imaginable health). The prespecified secondary comparison is at 12 months after randomisation. Earlier measurements will be used for descriptive and exploratory analyses.
Time frame: Baseline; 2 days, 2 weeks, 6 weeks, 3 months and 12 months after randomisation
Duration of sick leave
Duration of sick leave during the follow-up period, recorded in days.
Time frame: From randomisation to 12 months
Extent of sick leave
Extent of sick leave during the follow-up period. Data will be collected from medical records, the Swedish Spine Registry (Swespine) and the Swedish Social Insurance Agency (Försäkringskassan).
Time frame: From randomisation to 12 months
Healthcare visits related to lumbar disc herniation
Number of healthcare visits related to lumbar disc herniation or its treatment during the follow-up period.
Time frame: From randomisation to 12 months
Hospitalisations related to lumbar disc herniation
Number of hospitalisations related to lumbar disc herniation or its treatment during the follow-up period.
Time frame: From randomisation to 12 months
Re-interventions
Number and type of additional interventions for lumbar disc herniation during the follow-up period, including additional nerve root injections outside the study protocol.
Time frame: From randomisation to 12 months
Hospital readmissions
Number of hospital readmissions related to lumbar disc herniation or its treatment during the follow-up period.
Time frame: From randomisation to 12 months
Revision lumbar disc surgery
Number of revision operations following the index lumbar disc surgery during the follow-up period.
Time frame: From randomisation to 12 months
Adverse events
Number and type of adverse events, including bleeding, infection, neurological deterioration, allergic reactions, steroid-related complications and vasovagal reactions. Severity will be graded using the National Cancer Institute Common Terminology Criteria for Adverse Events
Time frame: From randomisation to 12 months
Serious adverse event
Number and type of serious adverse events, defined according to Good Clinical Practice criteria, including death, life-threatening events and events requiring or prolonging hospitalisation.
Time frame: From randomisation to 12 months
Surgical complications
Number and severity of surgical complications among participants undergoing surgery, classified using the Clavien-Dindo classification and categorised as minor or major according to the protocol.
Time frame: From randomisation to 12 months
Analgesic use
Administered and prescribed doses of analgesics during follow-up. Opioid doses will be converted to oral morphine equivalents where applicable.
Time frame: From randomisation to 12 months
Direct medical costs
Direct medical costs associated with treatment and follow-up, including procedures, medications, imaging, outpatient visits, hospitalisations and additional interventions.
Time frame: From randomisation to 12 months
Indirect costs
Costs of productivity loss associated with sick leave during the follow-up period.
Time frame: From randomisation to 12 months
Quality-adjusted life years
Quality-adjusted life years calculated from EQ-5D-3L index values over the follow-up period. Higher values indicate greater health benefit.
Time frame: From randomisation to 12 months
Incremental cost per surgery avoided
Difference in costs between the selective nerve root block and sham groups divided by the difference in the proportion of participants avoiding lumbar disc surgery.
Time frame: From randomisation to 12 months
Incremental cost per quality-adjusted life year gained
Difference in costs between the selective nerve root block and sham groups divided by the difference in quality-adjusted life years.
Time frame: From randomisation to 12 months
Long-term lumbar disc surgery
Proportion of participants who undergo surgery for the index lumbar disc herniation during long-term follow-up.
Time frame: From randomisation to 5 years
Long-term reoperations
Number and type of additional lumbar spine operations following the index lumbar disc surgery during long-term follow-up, including revision surgery.
Time frame: From randomisation to 5 years
Long-term complications
Number and type of complications recorded during long-term follow-up. Surgical complications will be classified according to the protocol.
Time frame: From randomisation to 5 years
Long-term healthcare visits related to lumbar disc herniation
Number of healthcare visits related to lumbar disc herniation during long-term follow-up.
Time frame: From randomisation to 5 years
Long-term hospitalisations related to lumbar disc herniation
Number of hospitalisations related to lumbar disc herniation during long-term follow-up.
Time frame: From randomisation to 5 years
Long-term leg pain intensity measured using the Visual Analogue Scale
Leg pain intensity measured using a Visual Analogue Scale (VAS) ranging from 0 to 100 mm, with higher scores indicating greater pain.
Time frame: At extended follow-up (2-5 years)
Long-term back pain intensity measured using the Visual Analogue Scale
Back pain intensity measured using a Visual Analogue Scale (VAS) ranging from 0 to 100 mm, with higher scores indicating greater pain.
Time frame: At extended follow-up (2-5 years)
Long-term leg pain intensity measured using the Numeric Rating Scale
Leg pain intensity measured using a Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain).
Time frame: At extended follow-up (2-5 years)
Long-term back pain intensity measured using the Numeric Rating Scale
Back pain intensity measured using a Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain).
Time frame: At extended follow-up (2-5 years)
Long-term Oswestry Disability Index
Disability measured using the Oswestry Disability Index (ODI), version 2.0. Scores range from 0 to 100, with higher scores indicating greater disability.
Time frame: At extended follow-up (2-5 years)
Long-term health-related quality of life measured using the EQ-5D-3L index
Health-related quality of life measured using the EQ-5D-3L and converted to an index using the selected value set. Higher values indicate better health; 1 represents full health, and negative values represent health states valued below death.
Time frame: At extended follow-up (2-5 years)
Long-term self-rated health measured using the EQ-VAS
Self-rated health measured using the EQ-VAS, ranging from 0 (worst imaginable health) to 100 (best imaginable health
Time frame: At extended follow-up (2-5 years)
Radiographic assessment of spinal degeneration and alignment
Radiographic assessment of signs of arthritis, segmental alignment and global sagittal balance using a standing whole-spine radiograph.
Time frame: At the 1-year follow-up
Plan to share: Yes — IPD underlying published manuscripts will be accessible for other researchers. The investigators in charge will be responsible for reviewing access requests. Crude data, randomization procedures and intervention details can be shared with other researchers upon reasonable request.
Supporting information: Study protocol, Statistical analysis plan
Time frame: Data and supporting information will be available upon approved request beginning 12 months after publication of the results, provided that the study has been completed, and will remain available for five years thereafter.
Access criteria: Qualified researchers may request access to anonymised individual participant data underlying published results and relevant supporting documentation by contacting the principal investigator. Requests must include a research proposal specifying the scientific aims, data required and planned analyses. Access will be subject to scientific review, assessment of participant confidentiality, applicable ethical and institutional requirements, and a data use agreement where applicable. Approved data will be provided through a secure transfer mechanism.
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