Correction of trigonocephaly after endoscopic strip craniectomy with postoperative helmet orthosis therapy: a 3D stereophotogrammetric study

Abstract

OBJECTIVE Endoscopic strip craniectomy with postoperative helmet orthosis therapy (ESCH) has emerged as a less invasive alternative to fronto-orbital remodeling for correction of trigonocephaly. However, there is no standardized objective method for monitoring morphological changes following ESCH. Such a method should be reproducible and avoid the use of ionizing radiation and general anesthesia for diagnostic imaging. The authors analyzed a number of metrics measured using 3D stereophotogrammetry (3DSPG) following ESCH, an imaging alternative that is free of ionizing radiation and can be performed on awake children. METHODS 3DSPG images obtained at two time points (perisurgical and 1-year follow-up [FU]) of children with metopic synostosis who had undergone ESCH were analyzed and compared to 3DSPG images of age-matched control children without craniofacial anomalies. In total, 9 parameters were measured, the frontal angle and anteroposterior volume in addition to 7 novel parameters: anteroposterior area ratio, anteroposterior width ratios 1 and 2, and right and left anteroposterior diagonal ratios 30 and 60. RESULTS Six eligible patients were identified in the operated group, and 15 children were in the control group. All 9 parameters differed significantly between perisurgical and age-matched controls, as well as from perisurgical to FU scans. Comparison of FU scans of metopic synostosis patients who underwent surgery to scans of age-matched controls without metopic synostosis revealed that all parameters were statistically identical, with the exception of the right anteroposterior diagonal ratio 30, which was not fully corrected in the treated patients. The left anterior part of the head showed the most change in surface area maps. CONCLUSIONS In this pilot study, ESCH showed satisfactory results at 1 year, with improvements in all measured parameters compared to perisurgical results and normalization of 8 of 9 parameters compared to an age-matched control group. The results indicate that these parameters may be useful for craniofacial units for monitoring changes in head shape after ESCH for trigonocephaly and that 3DSPG, which avoids the use of anesthesia and ionizing radiation, is a satisfactory monitoring method.