It depends upon the patient’s anatomy and the type of pseudoarthrosis. On most individuals, the C7-T1 space can be reached anteriorly but at T1-2, only 40-50% of subjects can be reached due to anatomy. If the anterior approach is used, I would use a structural autograft like iliac crest. If the posterior approach is used, I would use a bone enhancer such as BMP or autograft or both.
Dr. Corenman