A Randomized Intra-Patient Controlled Trial of MagnetOs™ Putty vs Autograft in Instrumented Posterolateral Spinal Fusion in Idiopathic Scoliosis Patients (MAIS)

March 30, 2026 updated by: M.C. Kruyt, MD, PhD, UMC Utrecht

SUMMARY Rationale: Delayed union is a problem in adolescent idiopathic scoliosis (AIS) surgery, especially at the distal end of the construct. Surgeons therefore use local autograft or bone graft substitutes to prevent loss of correction and/or anchor failure and additionally restrict patients' activities during the first year. The concept of this study was developed after the promising results of the MaxA study (METC 18-311), where we compared the efficacy of BCP<μm ceramic granules (MagnetOs™ Granules) to autograft in posterolateral fusion (PLF). This randomized intra-patient-controlled trial indicated superior spinal fusion rates for the BCP<μm condition. The current investigational product (MagnetOs™ Putty) is made of the same MagnetOs™ Granules embedded in a fast-resorbing polymeric binder to improve surgical handling. If MagnetOs™ Putty allows better and faster fusion in scoliosis patients, it is possible to mobilize them faster and even abandon post-operative activity restrictions.

Objective: The primary objective is to demonstrate superiority and safety of MagnetOs™ Putty compared to autograft regarding the posterolateral spinal fusion rate, in instrumented PLF in AIS patients. The secondary objectives encompass comparisons of posterolateral spinal fusion rates on different levels at various points in time, monitoring the changes in trunk rotation, evaluating quality of life and patient's experiences as well as improving the reliability of Hounsfield unit measurements.

Study design: Multicenter, randomized, controlled superiority trial with intra-patient comparisons over a 1-year follow-up.

Study population: 140 patients between 12 to 30 years with AIS qualified for scoliosis surgery with lowest instrumented vertebrae T12-L4.

Intervention: According to a randomization scheme, one side of the caudal PLF will be grafted with the MagnetOs™ Putty and the other side with local bone. The rest of the surgical procedure will be according to standard care.

Main study parameters/endpoints: The fusion rate of MagnetOs™ Putty compared to standard fusion with local autograft, assessed locally and centrally through a three plane assessment tool at the caudal segment on CT scans at 3 or 6 months. The complication rate will be compared to the rate in control populations from literature.

Nature and extent of the burden and risks associated with participation, benefit, and group relatedness: The study population includes AIS patients between 12 to 30 years with an indication for PLF. Patient burden and risks are expected to be minimal. The post-operative follow-up will be according to standard care. Additional study procedures include the completion of patient-reported outcome measures (PROM) at four time points and a limited CT scan. Based on pre-clinical investigations and the results of the MaxA study, we expect MagnetOs™ Putty to perform better than the current treatment. This may benefit the patient as currently about 5% experience problems of delayed union in our own series.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

SUMMARY Rationale: Delayed union is a problem in adolescent idiopathic scoliosis (AIS) surgery, especially at the distal end of the construct. Surgeons therefore use local autograft or bone graft substitutes to prevent loss of correction and/or anchor failure and additionally restrict patients' activities during the first year. The concept of this study was developed after the promising results of the MaxA study (METC 18-311), where we compared the efficacy of BCP<μm ceramic granules (MagnetOs™ Granules) to autograft in posterolateral fusion (PLF). This randomized intra-patient-controlled trial indicated superior spinal fusion rates for the BCP<μm condition. The current investigational product (MagnetOs™ Putty) is made of the same MagnetOs™ Granules embedded in a fast-resorbing polymeric binder to improve surgical handling. If MagnetOs™ Putty allows better and faster fusion in scoliosis patients, it is possible to mobilize them faster and even abandon post-operative activity restrictions.

Objective: The primary objective is to demonstrate superiority and safety of MagnetOs™ Putty compared to autograft regarding the posterolateral spinal fusion rate, in instrumented PLF in AIS patients. The secondary objectives encompass comparisons of posterolateral spinal fusion rates on different levels at various points in time, monitoring the changes in trunk rotation, evaluating quality of life and patient's experiences as well as improving the reliability of Hounsfield unit measurements.

Study design: Multicenter, randomized, controlled superiority trial with intra-patient comparisons over a 1-year follow-up.

Study population: 140 patients between 12 to 30 years with AIS qualified for scoliosis surgery with lowest instrumented vertebrae T12-L4.

Intervention: According to a randomization scheme, one side of the caudal PLF will be grafted with the MagnetOs™ Putty and the other side with local bone. The rest of the surgical procedure will be according to standard care.

Main study parameters/endpoints: The fusion rate of MagnetOs™ Putty compared to standard fusion with local autograft, assessed locally and centrally through a three plane assessment tool at the caudal segment on CT scans at 3 or 6 months. The complication rate will be compared to the rate in control populations from literature.

Nature and extent of the burden and risks associated with participation, benefit, and group relatedness: The study population includes AIS patients between 12 to 30 years with an indication for PLF. Patient burden and risks are expected to be minimal. The post-operative follow-up will be according to standard care. Additional study procedures include the completion of patient-reported outcome measures (PROM) at four time points and a limited CT scan. Based on pre-clinical investigations and the results of the MaxA study, we expect MagnetOs™ Putty to perform better than the current treatment. This may benefit the patient as currently about 5% experience problems of delayed union in our own series.

Study Type

Interventional

Enrollment (Estimated)

140

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

AIS indicated for sugical treatment

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Autogaft on one side tof the lowest instrumented fusion this s the control condtion
Autogaft on one side tof the lowest instrumented fusion this is the control condition
Procedure: autograft
autograft is standard treatment
Experimental: MagenetOs putty on the other side of the lowest instrumented fusion
added to the removed facet joint
Device: MagnetOs putty 2.5cc
Putty will be added tot the removed facet joint of the LIV

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The fusion rate of MagnetOs™ Putty compared to standard fusion with local autograft, assessed locally and centrally through a three plane assessment tool at the caudal segment on CT scans at 3 or 6 months
Time Frame: The fusion rate of MagnetOs™ Putty compared to standard fusion with local autograft, assessed locally and centrally through a three plane assessment tool at the caudal segment on CT scans at 3 or 6 months
The fusion rate of MagnetOs™ Putty compared to standard fusion with local autograft, assessed locally and centrally through a three plane assessment tool at the caudal segment on CT scans at 3 or 6 months
The fusion rate of MagnetOs™ Putty compared to standard fusion with local autograft, assessed locally and centrally through a three plane assessment tool at the caudal segment on CT scans at 3 or 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

UMC Utrecht

Collaborators

Kuros BioSciences B.V.

Investigators

  • Principal Investigator: Moyo Kruyt, PhD, UMC Utrecht

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

May 1, 2026

Primary Completion (Estimated)

May 1, 2030

Study Completion (Estimated)

May 1, 2030

Study Registration Dates

First Submitted

March 30, 2026

First Submitted That Met QC Criteria

March 30, 2026

First Posted (Actual)

April 6, 2026

Study Record Updates

Last Update Posted (Actual)

April 6, 2026

Last Update Submitted That Met QC Criteria

March 30, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 24U-1701

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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