title: Prospective, randomized, controlled trial of silicate-substituted calcium phosphate versus rhBMP-2 in a minimally invasive transforaminal lumbar interbody fusion.
abstract: METHODS
  Prospective, randomized, controlled trial.
  
  
  OBJECTIVE
  To compare arthrodesis rates between patients undergoing a primary single-level minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) with either Actifuse or recombinant human bone morphogenetic protein-2 (rhBMP-2).
  
  
  BACKGROUND
  Preclinical animal studies suggest that silicate-substituted calcium phosphate (Actifuse) bone graft substitute offers equivalent or an increased fusion rate compared with other graft enhancers/extenders and rhBMP-2.
  
  
  METHODS
  Fifty-two patients undergoing a single-level unilateral MIS TLIF were evenly randomized into 2 cohorts as follows: the Actifuse cohort received Actifuse combined with 5 mL of bone marrow aspirate (n = 26; 50%), whereas the rhBMP cohort received 4.2 mg of rhBMP-2 (n = 26; 50%). A pre hoc G*Power analysis yielded a sample size of n = 26 that was determined through a 2-tailed distribution calculation. Computed tomographic analysis was performed at 6 months and 1 year postoperatively. Pre- and postoperative visual analogue scale scores were obtained to assess the clinical outcomes. Arthrodesis was determined by 2 separate, blinded orthopedic surgeons and a board certified radiologist.
  
  
  RESULTS
  At 1-year follow-up, 65% (17/26) of the Actifuse cohort and 92% (24/26) of the rhBMP-2 cohort demonstrated a radiographical arthrodesis (P = 0.01). In both study cohorts, the 1-year postoperative visual analogue scale scores significantly improved (P < 0.001). Pseudarthrosis rates at 1 year were 35.0% (9/26) and 7.7% (2/26) for the Actifuse and rhBMP-2 groups, respectively (P = 0.01, OR = 6.35, 95% CI = 1.22-33.1). A greater reoperation rate was noted in the Actifuse cohort (35.0%, 9/26) compared with the BMP-2 cohort (7.7%, 2/26; P = 0.01). One patient with BMP-2 also experienced symptomatic neuroforaminal bone growth (3.8%, n = 1/26).
  
  
  CONCLUSIONS
  Silicate-substituted calcium phosphate was associated with a significantly lower rate of arthrodesis than rhBMP-2 in a MIS TLIF. The patients with pseudarthrosis in both cohorts were all clinically symptomatic with an unimproved visual analogue scale score. Additional analysis of Actifuse and other graft enhancers/extenders are needed prior to the utilization for an MIS TLIF.
  
  
  METHODS
  2.
authors.affiliation: From the Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL.
authors.forename: Sreeharsha V
authors.initials: SV
authors.lastname: Nandyala
authors.forename: Alejandro
authors.initials: A
authors.lastname: Marquez-Lara
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Fineberg
authors.forename: Miguel
authors.initials: M
authors.lastname: Pelton
authors.forename: Kern
authors.initials: K
authors.lastname: Singh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage*; D017610:Calcium Compounds / Q000008:administration & dosage*; D002130:Calcium Phosphates / Q000008:administration & dosage*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control; D011446:Prospective Studies; D011859:Radiography; D011994:Recombinant Proteins / Q000008:administration & dosage; D017640:Silicates / Q000008:administration & dosage*; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage*
chemical_list: D055396:Bone Morphogenetic Protein 2; D017610:Calcium Compounds; D002130:Calcium Phosphates; D011994:Recombinant Proteins; D017640:Silicates; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; C020243:calcium phosphate; C031293:calcium silicate