Clinical and radiological outcomes of anterior cervical interbody fusion using hydroxyapatite spacer

Abstract

Objective: This is retrospective study of clinical and radiological outcomes of anterior cervical fusion using Bongros-HA (BioAlpha, Seongnam, Korea) which is a type of synthetic hydroxyapatite (HA) spacer to evaluate the efficacy in its clinical application and usefulness as a reliable alternative to autograft bone.

Methods: Twenty-nine patients were enrolled in this study and 40 segments were involved. All patients were performed anterior cervical interbody fusion using HA spacer and plating system. Indications for surgery were radiculopathy caused by soft-disc herniation or spondylosis in 18 patients, spondylotic myelopathy in 1 patient, and spinal trauma in 10 patients. Cervical spine radiographs were obtained on postoperative 1day, 1week, and then at 1, 2, 6, and 12 months in all patients to evaluate intervertebral disc height, and the degrees of lordosis. Cervical computed tomography was done at postoperative 12 month in all patients to confirm the fusion status. The mean period of clinical follow-up was 17 months.

Results: Complete interbody fusion was achieved in 100% of patients. Preoperative kyphotic deformities were corrected in all cases after surgery. Intervertebral disc height was well maintained during follow up period. There were no cases of graft extrusion, graft deterioration and graft fracture.

Conclusion: HA spacer is very efficient in achieving cervical fusion, maintaining intervertebral disc height, and restoring lordosis. When combined with the placement of a cervical plate, immediate stability can be achieved and graft related complication can be prevented.

Keywords: Anterior cervical discectomy; Fusion; Graft; Hydroxyapatite; Plate; Spacer.

Figures

Fig. 1

Photographs showing the porous hydroxyapatite bone fusion spacer used for cervical interbody fusion; Bongros-HA™ (BioAlpha, Seongnam, Korea) has a property of rectangular shape with a threaded design that prevent dislodgement of graft and maximize bony contact surface of graft.

Fig. 2

Evaluation of bone fusion rate; 6-point scoring system. Imaging studies (A, B and C) of a patient with C5-6-7 anterior cervical discectomy and fusion with hydroxyapatite spacer. Bone fusion check point (black arrow). Bone fusion check points (black arrow 1-6) represent bridging bone of six surfaces (anterior, posterior, superior, inferior and both lateral sides) around the spacer.

Fig. 3

Imaging studies of a 61-year old male patient with C3-6 anterior cervical discectomy and fusion with hydroxyapatite graft. The postoperative 6 month follow-up lateral X-ray (A) and postoperative 12 month follow-up coronal (B) and sagittal (C) computed tomography show lordotic alignment and formation of bridging bone.