Bone Regeneration after Midline Distraction Osteogenesis of the Forehead for Metopic Craniosynostosis

Background: Surgical treatment of metopic craniosynostosis has primarily been used to expand the anterior cranial vault, and several trials are assessing the possibility of increasing the width of the frontal bone.^1-3 We investigated the efficacy of midline distraction osteogenesis and assessed the extent of distraction required for an optimal cosmetic result.

Methods: We performed 10-year follow-up to assess 13 patients treated surgically for nonsyndromic metopic craniosynostosis. A vertical frontal craniotomy was performed along the midline of the forehead with the application of a distractor to achieve optimal distraction osteogenesis for adequate lateral advancement. Using computed tomography (CT), we evaluated the degree of bone regeneration and also growth-related changes in forehead contour.

Results: Patients were divided into 4 groups. Group 1: the dura was detached from the inner table of the frontal bone and the extent of distraction was >15 mm, group 2: the dura was attached to the frontal bone and the extent of distraction was >15 mm, group 3: the dura was attached to the frontal bone and the extent of distraction was ≤15 mm and V-shaped, and group 4: the dura was attached to the frontal bone and the extent of distraction was ≤15 mm using passive distraction osteogenesis with distraction performed at another site of the skull. CT in group 1 patients showed inadequate bone regeneration at the distraction site causing depression of the forehead, although an adequate width of forehead expansion was achieved. Thus, additional cosmetic surgery (dermofat graft) was needed to manage the contour deformity. CT in group 2 patients showed a small-sized focal bony defect secondary to deficient bone formation; however, this defect was grossly unnoticeable, and no additional surgery was necessary. CT in group 3 and 4 patients showed a completely filled bony defect with a satisfactory forehead contour without the need for additional procedures. Although only a few patients were examined and results were statistically insignificant, our findings are clinically significant to indicate the optimal extent of operation.

Conclusion: Expansion of the forehead width using distraction osteogenesis in patients with metopic craniosynostosis is a feasible procedure. Better results are observed in terms of bone regeneration and external contour when the dura is not detached from the frontal bone and the extent of distraction is ≤15 mm. Additional cosmetic procedures are warranted if the bony defect persists with a contour deformity.

Reference

1. Selber J, Reid RR, Gershman B, et al. Evolution of operative techniques for the treatment of single-suture metopic synostosis. Ann Plast Surg. 2007;59:6–13.

2. Hormozi AK, Shahverdiani R, Mohammadi HR, Zali A, Mofrad HR. Surgical treatment of metopic synostosis. J Craniofac Surg. 2011;22:261–265.

3. Kelleher MO, Murray DJ, McGillivary A, Kamel MH, Allcutt D, Earley MJ. Non-syndromic trigonocephaly: Surgical decision making and long-term cosmetic results. Childs Nerv Syst. 2007;23:1285–1289.