The shell technique: bilateral fronto-orbital reshaping in trigonocephaly

Abstract

The shell technique, used in the Pediatric Neurosurgical Department at the Catholic University, Rome, since the 1990s for the correction of trigonocephaly, is associated to a significant reduction in surgical time and intraoperative blood loss as compared to other procedures, while allowing an adequate remodelling of the bifrontal bone by means of multiple radial osteotomies. The technique does not necessitate the creation of a supraorbital bar, as the supraorbital ridges are modified in situ, further reducing the operative blood loss. In spite of reduced surgical time and manipulation, this procedure ensures aesthetic and functional results comparable to more extensive and complex cranial vault reshaping procedures. The main limitation of this technique is related to the surgical timing, as better results are obtained between 3 and 9 months of age, when the skull bone is still ductile to work with, thus allowing it to be remodelled by greenstick fractures. Moreover, in this age group, the cranial defects that result from the enlargement of the frontal bone flap by means of radial cuts and from the anterior displacement of its lateral portions may benefit from the more effective bone regeneration which characterizes younger children as compared to their older counterparts. A small number of cases showing either persistent hypotelorism or temporal depression have been observed in the post-operative period, although these residual deformities probably depend on a more extensive involvement of the cranial base in the synostotic process in these patients than on the procedure itself.

Correction of hypotelorism in isolated metopic synostosis

“…Treatment of the associated hypotelorism is still controversial. Some authors state that direct address of the hypotelorism may be unnecessary since the fronto-orbital reshaping, together with a midline osteotomy down to the fronto-nasal junction, would allow release of the growth restriction and hence promote indirect, secondary correction, especially if surgery is undertaken at an early stage [14,18,22]. Some improvement of hypotelorism has been reported after this type of approach, however never complete correction [18,22].…”

“…Some authors state that direct address of the hypotelorism may be unnecessary since the fronto-orbital reshaping, together with a midline osteotomy down to the fronto-nasal junction, would allow release of the growth restriction and hence promote indirect, secondary correction, especially if surgery is undertaken at an early stage [14,18,22]. Some improvement of hypotelorism has been reported after this type of approach, however never complete correction [18,22]. When direct surgical correction of hypotelorism is advocated, this is usually performed by the interposition of a bone graft to widen the supraorbital bandeau and support the lateral displacement after a sagittal osteotomy through the naso-frontal junction [13][14][15][16][17].…”

Metopic synostosis: Measuring intracranial volume change following fronto-orbital advancement using three-dimensional photogrammetry

“…Surgical treatment of metopic craniosynostosis includes remodeling of the forehead and advancement (Aryan et al, 2005;Di Rocco et al, 2013;Engel et al, 2011;Keshavarzi et al, 2009). At our department we prefer fronto-orbital advancement specially applied to trigonocephaly and the insertion of an inter-orbital bone graft, if necessary, to correct the hypotelorism (Engel et al, 2011).…”

The value of tranexamic acid during fronto-orbital advancement in isolated metopic craniosynostosis

“…Objectives for treatment include expansion and advancement of the supraorbital bandeau, widening of the temporal dimensions and rounding the forehead, and different surgical techniques have been described (Aryan et al, 2005;Di Rocco et al, 2013Metzler et al, 2014). At our unit, trigonocephaly is treated with fronto-orbital advancement (FOA) between the ages of 8 and 10 months (Engel et al, 2012(Engel et al, , 2013.…”