Spring-assisted correction of hypotelorism in metopic synostosis

Metopic synostosis, apart from the pointed forehead, typically is characterized by hypotelorism with egg-shaped orbits on cephalography and the frontoorbital axis parallel or even converging superiorly. The frontoorbital axis angle is a novel parameter for analyzing and describing the orientation of the orbits. Current methods of surgery often result in undercorrection of the almost ever-present hypotelorism. The present study was performed to analyze a new technique, capable in this respect, using steel wire springs in conjunction with a cranioplasty.

A retrospective study of 23 metopic synostosis patients operated on between 1999 and 2004 was conducted. A strip midline craniectomy and frontal reshaping were combined with the insertion of a steel wire spring across the midline craniectomy, forcing lateral displacement of the orbits. Preoperative and postoperative follow-up cephalograms were obtained, and the bony medial interorbital distance was measured and compared with the bony medial interorbital distance of a control group. Perioperative data and complications were noted.

Preoperative mean bony interorbital distance was 10.6 mm (range, 7.7 to 13.2 mm). It increased to 15.7 mm (range, 10.4 to 22 mm) at 1.5 months postoperatively and to 16.2 mm (range, 10.9 to 24.5 mm) 5 months postoperatively. Results as judged clinically ranged from little effect to a definitive overcorrection. The frontoorbital axis was improved in every case. Average frontoorbital axis was -4 degrees (range, -33 to 23 degrees) preoperatively and 28 degrees (range, 11 to 46 degrees) postoperatively.

It was concluded that a spring used together with a cranioplasty is a powerful tool for the correction of both hypotelorism and orbital shape in trigonocephaly.