Calvarial reshaping using bifocal bidirectional transport distraction osteogenesis

Purpose: The aim of this study is to assess 3-dimensional reconstruction of cranial defects by use of bifocal bidirectional transport distraction osteogenesis (BBTDO).

Materials and methods: This study was performed on 8 sheep, divided into a control group (n = 3) and treatment group (n = 5). Full-thickness cranial defects (50 x 40 mm) were created on calvaria. In the control group only the skin was closed. In the treatment group BBTDO was performed. Distraction was performed with a custom-made distraction device with a transport segment of 40 x 20 mm. After a 5-day period of latency, distraction was applied to the transport segment. During the first 20 days of distraction, the transport segment was distracted 1 mm in the forward direction and 0.5 mm in the upward direction. After the next 20 days of distraction, the transport segment was distracted 1 mm forward and 0.5 downward. After a total of 40 days' distraction, a 30-day consolidation period was applied. Macroscopic, radiologic (computed tomography with volume measurements), and histologic evaluations were done.

Results: No major complications were seen during the whole study period. In the control group the bone defects remained unhealed at the end of the study period. The same-sized defects in the treatment group healed with a convexity like the calvaria. Preoperative and postoperative cranial volume measurements of the treatment group animals showed an increase in cranial volume (P < .05). Histologic evaluation showed inductive bone regeneration and mature bone structure development within the distraction zone.

Conclusion: The BBTDO is an effective and safe technique for 3-dimensional closure of cranial defects.