Long-Term Metabolic Assessment of Cryopreserved Sternal Allograft: A Case Series

Background: Sternal resection and reconstruction with cryopreserved allografts provides a safe alternative to traditional methods of anterior chest wall reconstruction. Despite favorable results, successful integration of the graft sternum has never been demonstrated owing to the invasiveness of bone biopsy. We describe our experience of using 18F-sodium fluoride positron emission tomography/computed tomography scans as a noninvasive method of evaluating graft integration. Methods: Seven patients underwent surgery and radiologic follow-up. Surgical indications were sternal metastases (n = 5) and sternal dehiscence (n = 2). Sternal reconstruction was performed using a cryopreserved cadaveric sternal allograft fixed in place with titanium plates and screws. Follow-up with 18F-sodium fluoride positron emission tomography/computed tomography scans was performed at 1 and 2 years after surgery. Results: Three patients underwent total sternectomy. Two underwent partial upper sternectomy involving the manubrium, clavicle (1 patient only), and upper sternal body; and 2 had partial sternectomy of the sternal body and xiphoid process. Focal tracer accumulation occurred at the junctions between native bone and graft bone. The median maximum standardized uptake value at 1 year was 16.8 (range, 11.2 to 37.9; interquartile range, 13.6 to 19.4), and at 2 years it was 10.8 (range, 6.1 to 30.2; interquartile range, 8.9 to 15.1). In 6 cases accumulation was lower at the second scan, whereas in 1 patient the accumulation was higher at the second scan. Conclusions: Sternal reconstruction with cryopreserved allograft is safe and well tolerated. The 18F-sodium fluoride positron emission tomography/computed tomography scans are a useful and promising noninvasive method of demonstrating the metabolic activity of the graft and its incorporation into the host skeleton during follow-up.