Monobloc and facial bipartition osteotomies for reconstruction of craniofacial malformations: A study of extradural dead space and morbidity

This study evaluated the presence of extradural dead space following a monobloc or facial bipartition osteotomy and examined its natural history and relationship to postoperative infection and the presence of a ventriculoperitoneal shunt at the time of osteotomy in a consecutive series of patients with craniofacial dysostosis, frontonasal dysplasia, midline cranio-orbital clefts, and orbital hypertelorism. Only patients followed for at least 1 year were included in the study (range 1.3 to 5.5 years). The 23 patients studied were divided into three groups: 10 patients (mean age 9 years) underwent a monobloc osteotomy with advancement, 7 (mean age 8 years) a facial bipartition osteotomy with advancement, and 6 (mean age 7 years) a facial bipartition osteotomy without advancement. Standard craniofacial computed tomographic (CT) scans were obtained for each patient early after surgery (within 2 weeks in 13 patients and at 6 to 8 weeks in 10 patients) and again 1 year after surgery in every case. The extradural dead space was measured from a reproducible axial CT scan slice for each patient at each postoperative interval. An initial dead space was documented in the retrofrontal region of the anterior cranial fossa when the reconstruction incorporated forward projection of the osteotomy parts. This space was found to be obliterated by the expanded brain by 6 to 8 weeks in the patients examined by CT scan at this interval (n = 10) and by 1 year in all patients. Perioperative complications also were documented. The presence of a ventriculoperitoneal shunt at the time of osteotomy (7 of 23 patients) did not increase the risk of complications or alter the pattern of dead space closure after operation. True patients developed infectious complications that were managed without long-term consequences.