NCT07670533

Brief Summary

The goal of this clinical trial is to learn if there are differences in the effectiveness of decompression surgery alone versus decompression combined with extended fusion in patients with a previous lumbar spinal fusion who now present with symptoms of lumbar adjacent segment stenosis (LASS). The main questions it aims to answer are:

  • Does decompression alone differ from decompression combined with extended fusion with regard to clinical outcomes two years after surgery?
  • Are there any clinical or radiological characteristics that can predict better or worse outcomes two years after surgery?
  • Are there any differences between the treatment groups in terms of health economics? Researchers will compare decompression surgery alone versus decompression combined with extended fusion to see if there are any differences in treatment effect. Participants will:
  • Be randomized to one of the two surgical procedures
  • Visit the clinic four times postoperatively (at three months, 1, 2 and 5 years) for checkups and tests
  • Respond to questionnaires before surgery, and three months, 1, 2 and 5 years postoperatively

Trial Health

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Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
192

participants targeted

Target at P75+ for not_applicable

Timeline
75mo left

Started Aug 2026

Longer than P75 for not_applicable

Geographic Reach
1 country

3 active sites

Status
not yet recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

June 19, 2026

Completed
7 days until next milestone

First Posted

Study publicly available on registry

June 26, 2026

Completed
1 month until next milestone

Study Start

First participant enrolled

August 1, 2026

Completed
6 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

August 1, 2032

Expected
2 months until next milestone

Study Completion

Last participant's last visit for all outcomes

October 1, 2032

Last Updated

June 26, 2026

Status Verified

June 1, 2026

Enrollment Period

6 years

First QC Date

June 19, 2026

Last Update Submit

June 19, 2026

Conditions

Lumbar Adjacent Spinal StenosisChronic Low Back and Leg Pain

Keywords

Randomized trialPrevious lumbar spinal fusionSpinal stenosisSurgery

Outcome Measures

Primary Outcomes (1)

  • Oswestry Disability Index (ODI): Change in percent

    Improvement in the ODI score of a minimum of 30% from baseline (dichotomized variable: yes / no (yes = improved 30% or more, no = improved less than 30%)). The ODI is a questionnaire examin the level of disability based on 10 everyday activities of daily living. Each item consists of 6 statements which are scored from 0 to 5, with 0 indicating the least disability and 5 the highest level of disability. The total score is calculated as a percentage, with 0% indicating no disability and 100% indicating the highest level of disability.

    From enrollment to five years postoperatively (main endpoint is two years after surgery, but ODI will also be assessed before surgery, 3 months, one- and five years postoperatively)

Secondary Outcomes (9)

  • Oswestry Disability Index (ODI): Continuous

    From enrollment to five years postoperatively (main endpoint is two years after surgery, but ODI will also be assessed before surgery, 3 months, one- and five years postoperatively)

  • Numeric Rating Scale leg pain (NRS leg pain)

    From enrollment to five years postoperatively (main endpoint is two years after surgery, but NRS leg pain will also be assessed before surgery, 3 months, one- and five years postoperatively)

  • Numeric Rating Scale back pain (NRS back pain)

    From enrollment to five years postoperatively (main endpoint is two years after surgery, but NRS back pain will also be assessed before surgery, 3 months, one- and five years postoperatively)

  • Global perceived effect (GPE)

    From three months after surgery to five years postoperatively (main endpoint is two years after surgery, but GPE will also be assessed 3 months, one- and five years postoperatively)

  • Oswestry Disability Index (ODI): Change in percent

    From enrollment to five years postoperatively (main endpoint is two years after surgery, but ODI will also be assessed before surgery, 3 months, one- and five years postoperatively)

  • +4 more secondary outcomes

Other Outcomes (2)

  • Adverse Events of special interest (AESI) and Serious Adverse Events (SAEs)

    During the whole study period (five years)

  • Cost-effectiveness

    During the whole study period (five years)

Study Arms (2)

Decompression alone

EXPERIMENTAL

Patients allocated to decompression alone will be offered mid-line preserving decompression technique

Procedure: Decompression alone

Decompression with extended fusion

ACTIVE COMPARATOR

Patients allocated to decompression with extended fusion will be offered decompression with the use of vision enhancement, in addition to the procedure for the extended fusion involving bilateral pedicle screws with autologous bone transplant and/or bone substitutes.

Procedure: Decompression with extended fusion

Interventions

Decompression alonePROCEDURE

Patients allocated to decompression alone will be offered mid-line preserving decompression technique with the use of a vision-enhancing aid (microscope or magnifying glasses).

Decompression alone
Decompression with extended fusionPROCEDURE

Patients allocated to decompression with extended fusion will be offered decompression with the use of vision enhancement (microscope or magnifying glasses). The procedure for the extended fusion will involve bilateral pedicle screws with autologous bone transplant and/or bone substitutes. The use of an interbody device (cage) or not and decompression technique will be at the discretion of the surgeon. Bone grafts should be placed in the interbody device and either posteriorly and/or anteriorly to the interbody device. Autologous bone can be placed in the intervertebral space without a cage if it is not feasible e.g., due to a too narrow intervertebral disc space. Alternatively a posterior or posterolateral bone grafting can be performed.

Decompression with extended fusion

Eligibility Criteria

Age18 Years - 80 Years
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Participants must meet all the following criteria to be eligible for the study:
  • Clinical symptoms of spinal stenosis, defined as neurogenic claudication or radiating pain into the lower limbs with duration \>6 months
  • MRI-confirmed adjacent segment stenosis, proximal to a previously fused lumbar segment (fusion of maximum two levels between L1 and S1, any type of previous lumbar fixation procedure).
  • CT-verified solid fusion
  • Minimum time since previous fusion: one year
  • Eligible for both treatment alternatives: decompression with extended fusion and decompression alone.
  • Age between 18 and 80 years.
  • Insufficient improvement after at least 3 months of non-operative treatment.
  • Understand Norwegian language, spoken and written.

You may not qualify if:

  • Participants will be excluded if any of the following criteria are met:
  • Previous surgery at the actual adjacent stenotic level.
  • More than two fused lumbar levels.
  • Non-union (pseudoarthrosis) at the previously surgically fused level, radiologically verified.
  • Foraminal stenosis grade 3 at the adjacent level.
  • Spinal fracture.
  • Presence of cauda equina syndrome.
  • Complete motor deficit.
  • ASA physical status classification IV or V.
  • Alcohol or drug abuse.
  • Active cancer
  • Contradictions to MRI (e.g., Cardiac pacemaker electrodes, metal implants in the eye or brain, claustrophobia)
  • Disabling chronic neurological disease (e.g., Parkinson's disease, ALS, MS)
  • Ongoing serious psychiatric disease\&
  • Any condition that in the view of the investigator would suggest that the patient is unable to comply with the study protocol and procedures
  • +2 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (3)

Innlandet Hospital Gjøvik

Gjøvik, Norway

Location

Oslo University Hospital HF

Oslo, Norway

Location

University Hospital of North Norway

Tromsø, Norway

Location

MeSH Terms

Conditions

Spinal Stenosis

Interventions

Decompression

Condition Hierarchy (Ancestors)

Spinal DiseasesBone DiseasesMusculoskeletal Diseases

Intervention Hierarchy (Ancestors)

TherapeuticsPressureMechanical PhenomenaPhysical Phenomena

Central Study Contacts

Kjersti Storheim, Professor

CONTACT

0047-22117740uxskje@ous-hf.no

Eira K Ebbs, PhD

CONTACT

0047-22118080

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
DOUBLE
Who Masked
INVESTIGATOR, OUTCOMES ASSESSOR
Masking Details
The trial is open-label for participants, caregivers (surgeons and clinical staff). But investigators, outcome assessors and the statistician will be blinded to treatment allocation.
Purpose
TREATMENT
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Head of section

Study Record Dates

First Submitted

June 19, 2026

First Posted

June 26, 2026

Study Start

August 1, 2026

Primary Completion (Estimated)

August 1, 2032

Study Completion (Estimated)

October 1, 2032

Last Updated

June 26, 2026

Record last verified: 2026-06

Data Sharing

IPD Sharing
Will not share

Locations

NO(3)