Radiographic and Clinical Outcome of Silicate-substituted Calcium Phosphate (Si-CaP) Ceramic Bone Graft in Spinal Fusion Procedures.
METHODS
Retrospective cohort study.


OBJECTIVE
To evaluate the radiographic and clinical outcome of silicate-substituted calcium phosphate (Si-CaP), utilized as a graft substance in spinal fusion procedures.


BACKGROUND
Specific properties of Si-CaP provide the graft with negative surface charge that can result in a positive effect on the osteoblast activity and neovascularization of the bone.


METHODS
This study included those patients who underwent spinal fusion procedures between 2007 and 2011 in which Si-CaP was used as the only bone graft substance. Fusion was evaluated on follow-up CT scans. Clinical outcome was assessed using Oswestry Disability Index, Neck Disability Index, and the visual analogue scale (VAS) for back, leg, neck, and arm pain.


RESULTS
A total of 234 patients (516 spinal fusion levels) were studied. Surgical procedures consisted of 57 transforaminal lumbar interbody fusion, 49 anterior cervical discectomy and fusion, 44 extreme lateral interbody fusion, 30 posterior cervical fusions, 19 thoracic fusion surgeries, 17 axial lumbar interbody fusions, 16 combined anterior and posterior cervical fusions, and 2 anterior lumbar interbody fusion. At a mean radiographic follow-up of 14.2±4.3 months, fusion was found to be present in 82.9% of patients and 86.8% of levels. The highest fusion rate was observed in the cervical region. At the latest clinical follow-up of 21.7±14.2 months, all clinical outcome parameters showed significant improvement. The Oswestry Disability Index improved from 45.6 to 13.3 points, Neck Disability Index from 40.6 to 29.3, VAS back from 6.1 to 3.5, VAS leg from 5.6 to 2.4, VAS neck from 4.7 to 2.7, and VAS arm from 4.1 to 1.7. Of 7 cases with secondary surgical procedure at the index level, the indication for surgery was nonunion in 3 patients.


CONCLUSIONS
Si-CaP is an effective bone graft substitute. At the latest follow-up, favorable radiographic and clinical outcome was observed in the majority of patients.


METHODS
Level-III.
*Department of Neurological Surgery, Weill Cornell Brain and Spine Center †Department of Neuroradiology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, NY.
Marjan
M
Alimi
Rodrigo
R
Navarro-Ramirez
Karishma
K
Parikh
Innocent
I
Njoku
Christoph P
CP
Hofstetter
Apostolos J
AJ
Tsiouris
Roger
R
Härtl
D018786:Bone Substitutes / Q000494:pharmacology*; D016025:Bone Transplantation; D002130:Calcium Phosphates / Q000494:pharmacology*; D002516:Ceramics; D017586:Diskectomy; D005260:Female; D005539:Foramen Magnum / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D017640:Silicates / Q000494:pharmacology*; D013123:Spinal Fusion / Q000379:methods*; D016896:Treatment Outcome
D018786:Bone Substitutes; D002130:Calcium Phosphates; D017640:Silicates; C020243:calcium phosphate