Predictors of Outcomes in 900 Alveolar Bone Grafts

Abstract

Background: Significant discrepancies exist in the reported variables influencing alveolar bone graft outcomes. The purpose of this study was to evaluate graft success and identify outcome predictors in a large patient cohort using an objective cone beam computed tomography assessment tool.

Methods: Consecutive patients with cleft lip/palate who underwent alveolar bone grafting by 1 surgeon were included. Predictor variables were age at graft, oronasal fistula, canine position, concurrent premaxillary osteotomy, size of cleft, presence of bony palatal bridge, history of failed graft, location of primary repair, and surgeon experience. The outcome variable was graft success, determined using a cone beam computed tomography assessment tool and defined as a score of 3 or 4 (out of 4) in the following domains: vertical bone level, labiopalatal thickness, and nasal piriform symmetry.

Results: The sample included 900 alveolar cleft sites (median graft age, 9.9 years). The success rate was 94.6%. Presence of an erupted canine, large cleft defect, or premaxillary osteotomy were independent predictors of graft failure; presence of a bony palatal bridge was associated with graft success ( P < 0.05).

Conclusions: Presence of an erupted canine, large bony defect, or premaxillary osteotomy increase the risk of failure, and a bony palatal bridge portends success. Age 12 years or older, visible oronasal fistula, history of failed graft, primary cleft repaired at outside institution, and surgeon experience were associated with higher graft failure, but were not independent predictors when controlling for covariates. Surgeons should be aware that these factors in combination increase the odds of graft failure.

Clinical question/level of evidence: Risk, III.

Fig. 1.

Panoramic radiographs show left alveolar cleft with unerupted canine (above) and erupted canine (below).

Fig. 2.

Size of alveolar cleft defect measured as largest mesial–distal distance in axial plane.

Fig. 3.

Bony palatal bridge in a patient with right unilateral complete cleft lip and palate.

Fig. 4.

Vertical bone level of erupted cleft-adjacent mesial and distal teeth. Scores wer obtained by determining the distance from the cemento-enamel junction (CEJ) to the marginal bone level in the coronal plane, with 1 = CEJ to marginal bone 75% or greater root length (least successful); 2 = CEJ to marginal bone 50% or greater to less than 75% root length; 3 = CEJ to marginal bone 25% or greater to less than 50% root length; and 4 = CEJ to marginal bone less than 25% root length (most successful).

Fig. 5.

Labiopalatal (horizontal) thickness in axial plane was scored by comparing bone thickness with root width of cleft-adjacent teeth at cervical, middle, and apical thirds of cleft-adjacent teeth, with (above, left) 1 = labiopalatal thickness less than 50% root width of cleft-adjacent teeth (least successful); (above, right) 2 = labiopalatal thickness 50% or greater root width of cleft-adjacent teeth; (below, left) 3 = labiopalatal thickness 75% or greater root width of cleft-adjacent teeth; and (below, right) 4 = labiopalatal thickness 100% or greater root width of cleft-adjacent teeth (most successful).

Fig. 6.

Piriform symmetry was scored by comparing the height of the nasal floor on both sides in the coronal plane. For unilateral clefts, grafted and unaffected sides were compared, and for bilateral clefts, 2 grafted sides were compared for symmetry. Scores were as follows: (above, left) 1 = 6 mm or greater difference (least successful); (above, right) 2 = 3 or greater and less than 6 mm difference; (below, left) 3 = 1 or greater and less than 3 mm difference; and (below, right) 4 = less than 1 mm difference (most successful).