Abstract
Introduction
The most common complication related to the use of hydroxyapatite (HA) grafts for cervical anterior fusion is graft breakage. However, the implication of graft breakage in terms of loss of graft height, cervical alignment, plate migration, and clinical outcomes has not been adequately evaluated. The objective of this study is to evaluate the efficacy of HA grafts in combination with cervical plates in terms of fusion, restoration, and maintenance of cervical lordosis and to compare clinical and radiologic outcomes of patients who experienced graft breakage with patients who did not.
Patients and Methods
A prospective study of 40 patients who underwent anterior cervical fusion in which HA graft and plate systems were used. The chemical analysis of the implants showed 65% HA and 35% tricalcium phosphate and other ionic constituents found in bone mineral, such as carbonate, sodium, and magnesium ions. Preoperative assessments included clinical examinations, plain radiography, and magnetic resonance imaging. Postoperative assessments included clinical examinations, use of analgesics, and plain radiography. Flexion-extension radiography and computerized tomography scanning with sagittal and coronal reconstructions were also performed at the last visit.
Results
At the final follow-up evaluation, 80% of patients had an excellent clinical outcome, 15% had a good outcome, and 5% had a fair outcome based on Odom classification. All patients achieved lordotic alignment in the immediate postoperative period. Graft breakage was observed in 25% of cases. Patients who experienced HA block breakage have a 21 times greater chance of having an intervertebral height loss greater than 2 mm, a 4.9 times greater likelihood of undergoing loss of cervical alignment exceeding 3 degrees, and are 12.4 times more likely to present migration of the plates when compared with patients who had normal HA grafts.
Conclusion
Despite the positive clinical results observed in this study, breakage of HA grafts was a common complication occurring in 25% of patients. Graft breakage was associated with strut height loss of more than 2 mm, loss of cervical alignment exceeding 3 degrees, and a higher rate of plate migration. These changes related to the HA graft breakage demonstrate the necessity to continue searching for better grafting methods to perform cervical interbody fusion.