Mind The Gap: The Effect Of Postoperative Computed Tomography On Revision Alveolar Bone Grafting
Ema Zubovic, MD, Gary B. Skolnick, BS, Abdullah M. Said, BA, Richard J. Nissen, DDS, MS, Alison K. Snyder-Warwick, MD, Kamlesh B. Patel, MD, MSc.
Washington University Plastic Surgery, Saint Louis, MO, USA.
PURPOSE: Alveolar bone grafting (ABG) is an integral part of the care of patients with cleft lip & palate, typically performed during mixed dentition to stabilize the maxillary alveolar arch, provide bony support for the eruption of cleft-adjacent teeth, and achieve closure of nasoalveolar fistulae. Evaluation of bone graft success has traditionally been done via clinical examination and 2-dimensional dental radiographs, which have been shown to overestimate graft success and underestimate bone resorption relative to 3-dimensional computed tomography (CT). The effect of postoperative CT on the rate of revision bone grafting has not previously been reported.
METHODS: We retrospectively reviewed surgical, orthodontic, and radiographic records of all pediatric patients undergoing autologous bone grafting for alveolar clefts at a single center over a 10-year period (January 2009 to March 2019), with minimum 6-month follow-up. Variables collected included cleft diagnosis, sex, race, age at ABG, presence of secondary palatal fistula at time of ABG, treatment by cleft-specialized vs. community orthodontist, use of CT scan for graft success evaluation, and requirement for repeat ABG. Differences between patients with and without postoperative CT scans were analyzed with Mann-Whitney U test, Fisherís exact test, or Pearsonís chi-square test as appropriate. Variables influencing revision requirement were analyzed with logistic regression.
RESULTS: The study cohort included 87 patients. 59% were male; diagnoses were 64% unilateral cleft lip & palate, 25% bilateral cleft lip & palate, 9% unilateral cleft lip & alveolus, and 1% bilateral cleft lip & alveolus. Median age at ABG was 10.4 years (interquartile range 9.5-11.2 years) and autologous iliac crest bone graft was used exclusively in all cases. 58% of patients underwent postoperative CT scan at median interval of 10 months after surgery. Distributions of sex (p = 0.079), race (p = 0.578), and cleft diagnoses (p = 0.938), and mean age at ABG (p = 0.793) were statistically equivalent between patients with postoperative CT and those without CT. 44% of patients (22/50) with postoperative CT underwent repeat ABG for inadequate graft take, compared to 5% of patients (2/37) without postoperative CT (p < 0.001). Accounting for the use of postoperative CT, the presence of a secondary palatal fistula at time of original ABG had no independent effect on revision requirement (p = 0.525), nor did age at ABG (p = 0.569), treating orthodontist (p = 0.171), or cleft diagnosis (p = 0.734).
CONCLUSION: Computed tomography evaluation after alveolar bone grafting results in significantly increased revision rates for inadequate graft take. The presence of a secondary palatal fistula at time of original ABG is not predictive of revision requirement. These results may impact treatment planning and preoperative counseling for patients with cleft lip and palate undergoing alveolar bone grafting.
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