Bitemporal Depressions After Cranioplasty for Trigonocephaly

Abstract

Long-term results after cranioplasty for trigonocephaly often show bitemporal depressions and a residual hypotelorism. Both findings fuel the perception that the growth of the periorbital region and the forehead as a whole continues to be restricted, even after correction. The aim of this study is to evaluate the growth process of the periorbital region after correction for trigonocephaly in the long term. From 1986 to 2004, 123 patients underwent a cranioplasty for the correction of trigonocephaly. Cephalometric analysis was performed on the radiographs taken at presentation and on the last available radiograph before the age of 6 years (92 posteroanterior and 93 lateral cephalograms). Cephalic landmarks were used to analyze the growth of the forehead: Mo (medial orbital wall), Lo (lateral orbital wall), Losp (crosspoint between lateral orbital wall and sphenoid), and Eu (most lateral point of the skull). As a result of the lack of standardized cephalograms, growth ratios were used instead of absolute numbers. The Eu-Eu growth rate was higher than the Lo-Lo rate, which in its turn surpassed the Losp-Losp rate. An initial undercorrection of the hypotelorism was noted followed by an increased limited autocorrection. A higher Mo-Mo growth rate was noted in the group operated after 1 year of age. Increased interorbital growth accounts for an autocorrection of the residual hypotelorism. The growth rate of the anterotemporal area (Losp) was shown to be the lowest, which could explain the bitemporal depressions so often seen after a frontosupraorbital cranioplasty.

Guideline for Care of Patients With the Diagnoses of Craniosynostosis

“…Selber 120 found that the use of interpositional bone grafts in a series of 68 metopic children led to a decrease in the development of temporal dents. In a population of 92 trigonocephaly children in which no bone graft was used, Van der Meulen, 101 however, observed an automatic growth correction of the hypotelorism on x-ray, on account of which the use of an interpositional bone graft was judged to be unnecessary. From a photographic evaluation of 45 patients, Hilling 123 concluded that a satisfactory esthetic outcome on the long term was largely dependent on a good initial reconstruction.…”

“…The other end of the spectrum is characterized by a wedge-shaped forehead with hypotelorism and supraorbital retrusion on the basis of decreased growth of the forehead widthwise. 101 …”

“…At follow-up in the course of years after reconstruction of trigonocephaly, the lateral sides of the forehead often appear to revert to a certain degree and temporal depressions may be seen, which however seldom are cosmetically unsatisfactory to the degree that revision surgery is justified. 101 …”

Metopic synostosis

“…Temporal hollowing seemed to be the most commonly seen postoperative abnormality, which coincided with a notably reduced postoperative growth rate of the bony temporal region [97]. A subsequent study confirmed that reduced bone growth (and not soft tissue factors) was the major contributor to this temporal hollowing [99].…”

Trigonocephaly: A simple modified technique

“…[19] Reason for premature fusion of the metopic suture may be one or combination of following-Intrauterine compression; from the subjacent dura mater supplying osteoinductive growth factors and cellular elements to the suture mesenchyme; exposure to high level of thyroxine resulting from maternal, juvenile, or neonatal hyperthyroidism; deficient brain growth; primary abnormality of mesenchyme; rickets; hypercalcemia; and or gene mutation. [2122232425262728]…”