RCT of AttraX® Putty vs. Autograft in Instrumented Posterolateral Spinal Fusion

Spinal fusion, a surgical procedure frequently used for many spinal conditions requiring stabilization of the vertebral column, is currently performed by using large amounts of autologous bone graft or autograft. A substitute for this patient own bone would eliminate the graft harvesting morbidity that is currently one of the main disadvantages. Recently, a promising synthetic graft substitute has been developed that has shown favorable results in pre-clinical studies. This product is AttraX® Putty (CE-557130), a bioresorbable tricalcium phosphate (TCP), mixed with a fast resorbing polymer carrier to improve surgical handling. The aim of the current study is to clinically investigate AttraX® Putty as an alternative to autologous bone graft in adult patients qualified for instrumented posterolateral fusion of the thoracolumbar spine (T10-S1).

The study design is a patient and observer blinded, controlled, randomized, multi-center clinical trial with intra-patient comparisons. This means that each patient is it owns control. According to a randomization scheme, one side of the spine will be grafted with AttraX® Putty the other side receives bone harvest from the iliac crest, which is currently the gold standard.

The primary outcomes of this study are the posterior spinal fusion rate after one year (based on CT-scans), and potential serious adverse events related with AttraX® Putty. Secondary outcomes are the resorption characteristics during the first year, volume of bridging bone mass after one year, evaluation of iliac crest pain, correlation of the posterior fusion rate to the presence of interbody fusion after one year and the posterior spinal fusion rate after two years.

Inclusion criteria

• To be treated with instrumented posterolateral thoracolumbar spinal fusion, with or without additional posteriorly inserted interbody devices (PLIF, TLIF), because of (1) deformity, (2) structural instability and/or (3) expected instability as a result of decompression for spinal stenosis;
• Non-responsive to at least 6 months of non-operative treatment prior to study enrollment;
• Fusion indicated for one or more levels in the T10 to S1/ilium region;
• Willing and able to understand and sign the study specific Patient Informed Consent;
• Skeletally mature between 18 and 80 years of age;

Exclusion criteria

• Any previous surgical attempt(s) for spinal fusion (revision surgery);
• Previous treatments that compromise fusion surgery like irradiation;
• Previous autologous bone grafting procedures that compromise the quality and amount of iliac crest bone grafting;
• Indication for spinal fusion because of a traumatic reason, like a spinal fracture or traumatic instability;
• Active spinal and/or systemic infection;
• Spinal metastasis in the area intended for fusion;
• Systemic disease or condition, which would affect the subjects ability to participate in the study requirements or the ability to evaluate the efficacy of the graft (e.g. active malignancy, neuropathy);
• At risk to be non-compliant (e.g. (recently treated for) substance abuse, detainee, likely to immigrate);
• Participation in clinical trials evaluating investigational devices, pharmaceuticals or biologics within 3 months of enrollment in the study;
• Female patients who intend to be pregnant within 1.5 year of enrollment in the study;
• Body mass index (BMI) larger than 35 (morbidly obese);
• Being expected to require additional surgery to the same spinal region within the next 6 months;
• Current or recent (<1yr) corticosteroid use equivalent to prednisone ≥5mg/day, prescribed for more than 6 weeks.