FINDISC-Pain, Finnish Discectomy Trial on the Benefits and Harms of Surgery in Patients With Lumbar Disc Herniation (FINDISC-Pain)

FINDISC-Pain, Finnish Discectomy Trial - a Randomised, Placebo-surgery Controlled Trial. An Efficacy Trial Designed to Prove That Discectomy Can Work.

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.

Study Overview

• Status: Recruiting
• Conditions: Sciatica; Lumbar Disc Herniation With Radiculopathy
• Intervention / Treatment: Procedure: Microdiscectomy; Procedure: Placebo-surgery

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 122
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Olli Rytsölä, MD; Phone Number: +358504270094; Email: olli.rytsola@hus.fi
• Study Contact Backup: Name: Study coordinator; Email: saara.raatikainen@hus.fi

Study Locations

• Finland
  • Helsinki, Finland
    • Recruiting
    • Helsinki University Central Hospital
    • Contact: Olli Rytsölä; Phone Number: +358504270094; Email: olli.rytsola@hus.fi

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Microdiscectomy; Lumbar microdiscectomy	Procedure: Microdiscectomy; Lumbar microdiscectomy involves a surgical approach with skin and adipose layer incision, and subperiosteal dissection of posterior spinal muscles. After the approach the intervention involves lumbar spinal canal entry, resection of ligamentum flavum and removal of herniated disc fragments. Removal of bone from lamina and intervertebral disc space entry are performed only when necessary.
Placebo Comparator: Placebo; Placebo-surgery	Procedure: Placebo-surgery; The placebo-surgery procedure involves an identical incision and approach as in the microdiscectomy group, but it does not include entry to the spinal canal, and no removal of disc material or bone

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Worst leg pain intensity within past 24-hours (NRS 0-10, where 0 = no pain, 10 = worst possible pain)	Worst leg pain intensity will be measured using a 11-point Numeric Rating Ccale (NRS 0-10, where 0 = no pain, 10 = worst pain imaginable)	Recruitment, 1 day pre intervention, and 1 day, and 1, 3 and 6 weeks, and 3, 6 and 12 months post intervention. Primary endpoint at 6 weeks.
Patient acceptable symptom state (PASS)	PASS will be assessed by asking "Thinking about your recovery from back surgery - would you be satisfied with your current symptoms status (as experienced in the past 24-hours)?" Recorded as Yes / No. Further analysis will report the proportion of participants reporting a satisfactory symptom state at the primary endpoint (responder analysis).	1, 3 and 6 weeks, and 3, 6 and 12 months post intervention. Primary endpoint at 6 weeks.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oswestry Disability Index (ODI) (0-100, where 0 = no disability)		Recruitment, 1 day pre intervention, and 6 weeks, and 3, 6 and 12 month post intervention
Average leg pain intensity in past 24-hours, (NRS 0-10, where 0 = no pain, 10 = worst possible pain)		Recruitment, 1 day pre intervention, and 1 day, 1, 3 and 6 weeks, 3, 6, and 12 months post intervention
Back pain intensity in past 24-hours, (NRS 0-10, where 0 = no pain, 10 = worst possible pain)		Recruitment, 1 day pre intervention, and 1 day, 1, 3 and 6 weeks, 3, 6, and 12 months post intervention
Health-related quality of life (EQ-5D Visual Analogue Scale (EQ VAS), range 0 to 100, where 100 = the best imaginable health state)		Recruitment, 6 weeks and 12 months post intervention
Global Perceived Recovery (GPR) (7-point Likert scale, where 1 = completely recovered, 7 = worse than ever)		6 weeks and 12 months post intervention
Return-to-work (Yes/No/Part-time/Not working now)		6 weeks, 3, 6 and 12 months post intervention
Lower extremity muscle strength	Manual muscle testing for knee extension, ankle dorsiflexion, ankle plantar flexion, hallux extension (scale 0-5, where 0 = no muscle activation, 5 = normal strength)	Recruitment and 6 weeks post intervention
Lower extremity motor function	Lower extremity motor performance assessed during standardized clinical examination, including: ability to perform squat-to-stand, ability to walk on toes and ability to walk on heels. Each component will be recorded as Yes / No and analyzed separately.	Recruitment and 6 weeks post intervention
Straight leg raise (SLR) test	Positive or negative SLR test during standardized examination (recorded as positive/negative).	Recruitment and 6 weeks post intervention
Lower extremity sensory symptoms	Presence of sensory symptoms in the affected leg assessed during clinical evaluation (recorded as Yes/No).	Recruitment and 6 weeks post intervention
Harms	Harms occurring during the 12-month follow-up period. Harms will include pre-specified intra- and perioperative complications and events identified through participant questionnaires, unprompted participant contact, or medical record review. Events will be classified as adverse events (AE), serious adverse events (SAE), or suspected unexpected serious adverse events (SUSAR). Attribution will be categorized as: not related, unlikely related, possibly related, probably related, or definitely related to the intervention. Recorded as number of events.	From day of surgery through 12 months post-intervention
Health-related quality of life (EuroQol 5-Dimension 5-Level (EQ-5D-5L) index value)	EQ-5D-5L questionnaire, Finnish language version, using the Swedish value set. Score ranges from values below 0 (health states considered worse than death) to 1.00 (full health), where higher scores indicate better health-related quality of life.	Recruitment, 6 weeks and 12 months post intervention

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Magnetic resonance imaging (MRI)	Radiological assessment for lumbar disc herniation as Yes/No. If yes, further assessment of side (right / left), level (L3/4, L4/5, L5/S1) and type of hernia (protrusion / extrusion / sequestered). Also if yes, nerve root compression assessed on a 4-point scale: Certain / Probable (likelihood > 50%) / Possible (likelihood < 50%) / Definitely not	Recruitment, 3 and 12 months
Blinding fidelity (methodological measure)	Participant assumed group (study arm) allocation as Microdiscectomy / Placebo / Uncertain	12 months post intervention

Collaborators and Investigators

• Sponsor: Helsinki University Central Hospital
• Investigators: Study Director: Teppo Järvinen, Professor, Helsinki University Central Hospital

Study record dates

Study Major Dates

• Study Start (Actual): February 19, 2026
• Primary Completion (Estimated): December 1, 2030
• Study Completion (Estimated): December 1, 2030

Study Registration Dates

• First Submitted: February 3, 2026
• First Submitted That Met QC Criteria: February 11, 2026
• First Posted (Actual): February 18, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: randomized controlled trial; Surgery; Placebos; discectomy; placebo-controlled trial; patient acceptable symptoms state
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Neuromuscular Diseases; Peripheral Nervous System Diseases; Neuralgia; Mononeuropathies; Sciatic Neuropathy; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Sciatica
• Other Study ID Numbers: HUS/355/2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All collected IPD provided that current legislation permits it.
• IPD Sharing Time Frame: After publication of main results, to be specified later.
• IPD Sharing Access Criteria: To be determined.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE

Drug and device information, study documents

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