The FINDISC trial studies whether common back operation, microdiscectomy, is effective and safe for treating sciatica caused by a lumbar disc herniation. The study includes people whose leg pain has not improved after at least six weeks of non-surgical treatment.

The FINDISC trial aims to recruit and randomly allocate 122 participants to receive either the actual operation (discectomy) or a placebo (sham) surgery. The placebo (sham) procedure involves anesthesia and an approach similar to the real operation, but no removal of disc material or bone. Participants and healthcare staff, excluding the surgical team, will not know which treatment was given. The study compares pain relief, recovery, daily functioning, quality of life, and harms between the two groups.

The goal of the study is to provide reliable evidence to help patients and clinicians decide whether microdiscectomy offers meaningful benefits compared with placebo surgery.

FINDISC is a randomized, placebo-surgery-controlled clinical trial evaluating the efficacy and safety of microdiscectomy for lumbar disc herniation causing sciatica. The trial includes adults with persistent sciatica symptoms that have not resolved despite at least six weeks of nonoperative care.

Sciatica caused by lumbar disc herniation is a common and disabling condition that can result in prolonged pain, functional limitations, and absence from work. Although most patients improve without surgery, microdiscectomy is frequently offered to patients with ongoing symptoms, and the use of this procedure varies substantially across countries and healthcare systems. Previous randomized trials suggest that surgery may provide faster symptom relief than nonoperative treatment; however, the magnitude and durability of this benefit remain uncertain. Most existing studies are unblinded and have high rates of crossover from nonoperative care to surgery, which limits the ability to determine the true treatment effect of the surgical procedure itself. Because surgical interventions are associated with placebo effects, particularly for subjective outcomes such as pain and perceived recovery, a placebo- surgery-controlled trial is needed to distinguish the specific effects of microdiscectomy from nonspecific effects related to undergoing surgery.

Participants are randomized in a 1:1 ratio to receive either conventional microdiscectomy or placebo surgery. The placebo procedure is designed to mimic surgery but does not include entry to the spinal canal, i.e. removal of disc material or bone. Participants, healthcare professionals involved in post-operative care, outcome assessors, data analysts, and investigators interpreting the results are blinded to treatment allocation. The surgical team performing the procedure is not blinded and has no role in further care and follow-up of the participants.

Outcomes assessed include pain, patient acceptable symptom state (PASS), global perceived recovery, disability, health-related quality of life, and the frequency of serious adverse events and reoperations. The study uses a superiority design, with the hypothesis that microdiscectomy leads to faster symptom relief than placebo surgery while maintaining an acceptable safety profile.

All procedures are performed at tertiary spine centers by experienced orthopedic or neurosurgeons. Post-operative care follows standard hospital practice, with general guidance provided to ensure consistency across sites.

Eligible patients who decline randomization are invited to participate in a parallel observational cohort, from which only baseline data are collected to assess potential selection bias.

A pilot phase enrolling 30 participants at one center is conducted to assess feasibility and safety. If no major protocol changes are required, data from the pilot phase will be included in the main trial analyses.

Participant safety is overseen by an independent Data Safety Monitoring Board (DSMB), which monitors adverse events and approves the statistical analysis plan. Trial data are collected by trained research staff blinded to treatment allocation and stored in a secure electronic data capture system.

Inclusion Criteria:

• Age 18-60 years
• Diagnosed unilateral lower extremity radiculopathy (sciatica) secondary to lumbar disc herniation (LDH)
• Single LDH at the level of L3/4, L4/5 or L5/S1 on magnetic resonance imaging
• Symptom duration minimum 6 weeks
• NRS worst leg pain 5 or higher
• Patient has not responded to at least one form of non-operative care
• Patient willing to undergo surgery
• Patient willing and able to give consent and comply with study procedures
• Sufficient proficiency in the language of the study site to provide informed consent and comply with study procedures

Exclusion Criteria:

• Doubtful nerve root compression
• Spinal stenosis or any other confounding spinal condition
• Far lateral disc herniation
• Serious neurological deficit
• Previous spinal surgery
• Any contraindication to MRI
• BMI > 35 or lumbar subcutaneous fat > 50 mm as determined from the MRI
• ASA classification > 2
• Being pregnant

All collected IPD provided that current legislation permits it.

After publication of main results, to be specified later.

To be determined.

All care providers except for the surgical team providing the study intervention will be masked (i.e. all postoperative care providers are masked). Study statistician will also be masked.