i-Factor™ Bone Graft vs Autograft in Anterior Cervical Discectomy and Fusion: 2-Year Follow-up of the Randomized Single-Blinded Food and Drug Administration Investigational Device Exemption Study

BACKGROUND: i-Factor (TM) Bone Graft (Cerapedics Inc, Westminster, Colorado) is a composite bone substitute material consisting of P-15 synthetic collagen fragment adsorbed onto anorganic bone mineral suspended in an inert biocompatible hydrogel carrier. A pivotal, noninferiority, US FDA Investigational Device Exemption study demonstrated the benefits of i-Factor (TM) compared to local autograft bone in single-level anterior cervical discectomy and fusion at 1-yr postoperative. OBJECTIVE: To report 2-yr follow-up. METHODS: Subjects randomly received either autograft (n = 154) or i-Factor (TM) (n = 165) in a cortical ring allograft and followed using radiological, clinical, and patient-reported outcomes. RESULTS: At 2 yr, the fusion rate was 97.30% and 94.44% in i-Factor (TM) and autograft subjects, respectively (P=.2513), and neurological success rate was 94.87% (i-Factor (TM)) and 93.79% (autograft; P =.7869). Neck Disability Index improved 28.30 (i-Factor (TM)) and 26.95 (autograft; P =.1448); Visual Analog Scale arm pain improved 5.43 (i-Factor (TM)) and 4.97 (autograft) (p =.2763); Visual Analog Scale neck pain improved 4.78 (i-Factor (TM)) and 4.41 (autograft; P =.1652), Short Form-36 (SF-36v2) Physical Component Score improved 10.23 (i-Factor (TM)) and 10.18 (autograft; P=. 4507), and SF36v2Mental Component Score improved 7.88 (i-Factor (TM)) and 7.53 (autograft; P=.9872). The composite endpoint of overall success (fusion, Neck Disability Index improvement > 15, neurological success, and absence of reoperations) was greater in i-Factor (TM) subjects compared to autograft subjects (69.83% and 56.35%, respectively, P=. 0302). Twelve (7.45%) i-Factor (TM) subjects and 16 (10.53%) autograft subjects underwent re-operation (P =.3411). There were no allergic reactions associated with i-Factor (TM). CONCLUSION: Use of i-Factor (TM) in anterior cervical discectomy and fusion is effective and safe, and results in similar outcomes compared to local autograft bone at 2 yr following surgery.