Lumbar interbody fusion augmented with a novel bioactive glass bone graft substitute: safety and fusion outcomes from a retrospective cohort study — The International Society for the Study of the Lumbar Spine
  1. Schedule
  2. GENERAL POSTER SESSION
  3. Lumbar interbody fusion augmented with a novel bioactive glass bone graft substitute: safety and fusion outcomes from a retrospective cohort study

Lumbar interbody fusion augmented with a novel bioactive glass bone graft substitute: safety and fusion outcomes from a retrospective cohort study (#1086)

Hyun Bae 1 , Adaire O'Brien 2 , Chambliss Harrod 2 , Margaret Mangelli 2 , George Hanna 1 , Luc Fortier 3
  1. Cedars-Sinai, Los Angeles, CA
  2. Bone and Joint Clinic of Baton Rouge, Baton Rouge, LA
  3. Georgetown University, Washington, DC

Introduction:  Lumbar interbody fusion (LIF) may treat a range of degenerative lumbar pathologies, including degenerative disc disease (DDD), spondylolisthesis, and spondylosis.  Selecting the ideal bone graft material is important to optimize graft incorporation and promote efficacy and safe use. Bioactive glass (45S5) is a unique, synthetic, ceramic bone graft substitute that is known to form hydroxyapatite (HA) on its surface within 24 hours when exposed to aqueous solution. The purpose of this study was to evaluate the fusion and safety outcomes of a bioactive glass bone graft substitute in lumbar interbody fusion (LIF) procedures performed by a single surgeon.

Methods:  The study included a retrospective cohort with prospective data collection, performed under an IRB-approved protocol. Patients undergoing surgery for non-degenerative pathologies were excluded.  The full safety cohort consisted of a consecutive series of patients who underwent LIF between April 2017 and April 2018. A combination of bioactive bone graft (FIBERGRAFT® BG Putty) and autograft was used at each LIF level. The full safety cohort consisted of 66 patients (58% female, average age 65.2 years) diagnosed with DDD (57.5%), stenosis (69.7%), degenerative scoliosis (30.3%), and/or spondylolisthesis (43.9%).  Eight patients declined prospective study participation and 4 were not eligible due to revision LIF surgeries, resulting in CT fusion assessment in 54 subjects. CT scans were done at a minimum of 8 months postop. De-identified images were evaluated independently by the principal investigator to determine fusion status at each level using the grading method of Brantigan and Steffee as modified with the Fraser definition of locked pseudoarthrosis (BSF scale)1-3.  CTs were also inspected for subsidence and cage migration, expulsion, or damage.  Patient demographics and perioperative variables were summarized with descriptive statistics. Incidence of LIF revision and other adverse events as well as the overall fusion rate were computed. Continuous variables were analyzed by Student’s t-test, and categorical variables were analyzed by Fisher’s exact test, with p < 0.05 considered statistically significant.

Results:  CT fusion assessment was done for 54 patients (87 levels) at 19.9±9.6 months after LIF surgery.  Across all levels, the fused (BSF-3) rate was 89.7%; the rate of locked pseudoarthrosis (BSF-2) was 9.8%, and the rate of pseudoarthrosis (BSF-1) was 1.1%.  Of the 33 levels performed by TLIF approach, 85.3% were BSF-3, 11.8% were BSF-2, and 2.9% were BSF-1. Similar rates were found for the ALIF approach, with 88.2% BSF-3 and 11.8% BSF-2. The LLIF levels had the highest rate of fusion with 95.7% BSF-3 and 4.3% BSF-2. Separately, 6 cases of cage subsidence were noted on CT. There was one instance of cage migration noted in the adverse event analysis, but no cases of expulsion or damage.

Discussion:  The study results show an acceptable rate of fusion for all approaches and similar rates of AEs compared to other LIF studies4. It is reasonable to suggest that this bioactive bone graft augmented with autologous bone provides comparable fusion results and safety profile to previously published results.

 

  1. Fogel et al. Spine J 8(4) 2008.
  2. Brantigan et al. Spine 18(14) 1993.
  3. Santos et al. Spine 28(10) 2003.
  4. Lee et al. Clin Orthop Surg 3, 2011.
#ISSLS2022