Discussion: Five-Year Follow-Up of Midface Distraction in Growing Children with Syndromic Craniosynostosis
Knowledge of the effects of any surgical intervention on subsequent growth is extremely important for those operating on children. Surgeons-in-training have long been admonished to refrain from early nasal, palatal, and maxillary surgery out of concerns for negatively impacting growth. Initially, midfacial advancements were reserved for skeletally mature individuals; however, recognition of the need to treat obstructive sleep apnea in young children and the desire to provide timely improvements in social acceptance have led surgeons to operate earlier and earlier. A preliminary study on immature pigs suggested that midfacial advancements had little to no effect on the subsequent growth of the maxilla.1 It turns out that children with syndromic craniosynostosis are different. Subsequent investigations revealed an absence of forward growth following traditional nondistracted Le Fort III advancements.2,3 Might the distracted Le Fort III advancements be different? Bone distraction includes a consolidation phase that eliminates the need for rigid fixation; thus, perhaps this lack of restraint would allow growth to proceed unimpeded. The first study to assess maxillary stability following external halo–based Le Fort III distractions revealed that in spite of both greater forward advancements and an absence of rigid fixation, not only was no relapse noted, there was also no cephalometrically measurable anterior maxillary growth for up to 5 years postoperatively, a finding ensuing studies were to independently corroborate.4–6 In this current issue of Plastic and Reconstructive Surgery, Patel et al. report a follow-up evaluation of a previously described cohort of children treated with halo-distraction Le Fort III advancements. These procedures were performed at a mean age of 5.7 years, with 11 of 17 patients younger than 5 years. The authors found little subsequent movement of the maxilla with no significant forward growth noted 5 years after surgery (orbitale had retruded 0.6 mm., and the A point had advanced 2.1 mm). However, their measurements did reveal that a small degree of inferior maxillary descent had occurred (5.2 mm), a finding we have also noted in our own patients undergoing midfacial distraction. Depending on the method used and experience of the examiner, the accuracy of cephalometric analyses has been calculated to be between 0.5 and 2.9 mm, suggesting that these findings are truly significant.7,8
This new study provides surgeons with important confirmatory data. Of note, the patients in this current series were treated almost 4 years younger than at our center (5 versus 9 years), a finding that caries some important implications. The first is that regardless of the age of initial surgery, no further forward growth of the maxilla should be expected following a midfacial osteotomy (and there is no reason to believe that either a bipartition or monobloc should be any different). In their Discussion, the authors pose an important question: How many patients might require a second Le Fort III procedure? The two presented case examples, each 5 years from surgery, reveal that over time, in spite of measured maxillary stability, a relative recurrence of mild midfacial hypoplasia has occurred. In examining our own series of distracted patients who had all reached skeletally maturity, we found that 25 percent had either undergone a secondary Le Fort III procedure or were judged to benefit from a repeated procedure.9 A subanalysis of our patients revealed three associations with the need for a secondary advancement: (1) a greater degree of midfacial hypoplasia; (2) less of a distracted advancement; and (3) surgery at a younger age. Surgeons have control over only two of these three factors.