Prospective analysis of secondary alveolar bone grafting using computed tomography.

PURPOSE: This study radiographically evaluated the quantity and quality of secondary alveolar bone grafts from the anterior iliac crest to maxillary alveolar clefts in cleft lip and palate patients with the use of computed tomography. PATIENTS AND METHODS: A 1-year prospective study was conducted by using 14 unilateral and bilateral cleft lip and palate patients. Axial and coronal computed tomography (CT) scans were obtained during the immediate postoperative phase and at 1-year follow-up. RESULTS: This study showed that the average alveolar cleft requires a bone graft volume ranging from 0.9 to 3.6 cm3, with a mean volume of 2.10 cm3. The percentage of bone loss derived from the linear dimensional changes to the alveolar bone graft between the immediate postoperative and follow-up CT scans were as follows: 17.9% in maximal bone height, 29.9% in maximal anteroposterior bone width, and 13.7% in maximal transverse width. As compared with the linear measurements, the volumetric analysis showed a disproportional amount of volume loss equaling 43.7% and 42.5% in the coronal and axial studies, respectively. This showed a total average volume loss of 43.1% at approximately 1 year after the secondary alveolar cleft repair. However, as the canine tooth erupts through the bone graft, it can account for up to 53.4% of the total average volume loss. All 14 patients (17 clefts) showed bone bridging between the alveolar cleft radiographically, with good incorporation and maturation of the bone graft, and no recurrence of the oronasal fistula. CONCLUSION: The CT scan is a valuable radiographic imaging modality to assess and follow the clinical outcome of secondary alveolar bone grafting.