Radiation-free 3D head shape and volume evaluation after endoscopically assisted strip craniectomy followed by helmet therapy for trigonocephaly
Introduction
Craniosynostosis is the premature fusion of cranial sutures occurring at 1 in 2000 to 1 in 2500 live births (Slater et al., 2008). Treatment for craniosynostosis comes with different approaches. Trigonocephaly has two main approaches; the open cranial vault reconstruction and (endoscopic) suturectomy with spring- or/helmet therapy (Keshavarzi et al., 2009, Hinojosa, 2012, Ozlen et al., 2011, Jimenez and Barone, 1998, Barone and Jimenez, 1999). Objective comparison, follow-up and evaluation of these approaches remain difficult. Modern clinical diagnosis of head shapes and follow-up after surgical craniosynostosis interventions usually rely on the use of CT-scans, cranial x-rays and in the past few years also three dimensional (3D) photogrammetry (Marcus et al., 2007, Marcus et al., 2009, Saber et al., 2012, Delye et al., 2015, Le et al., 2014, McKay et al., 2010, Wilbrand et al., 2012). 3D photogrammetry using 3D photo systems were introduced as a radiation-free alternative but are limited to capturing soft tissue surfaces lacking the bony structures used in traditional follow-up. However it is possible to use 3D photos for objective follow-up. A common reference point for skull comparison is the sella turcica since its relative position is assumed to be more or less stable during skull growth (Björk, 1955). A new method to determine a similar reference point, the computed cranial focal point (CCFP), was proposed using a 3D surface from a 3D photo (De Jong et al., 2015). The CCFP has a fixed location relative to the sella turcica. This allows orienting 3D photos of the head in the sella turcica-nasion plane anchored to the sella turcica for radiation-free longitudinal follow-up.
It is possible to perform radiation-free longitudinal follow-up using 3D photos and we want to initiate this practice by describing our methodology for this follow-up as well as the results for the endoscopically assisted craniosynostosis surgery. At our institute we have a database of 3D photos of patients who underwent this surgery. Using the CCFP for registration of 3D photos we are able to perform longitudinal evaluations. We evaluate the head shape changes over time to determine the growth pattern in these patients that underwent this surgery. Furthermore we look at the longitudinal volume change of the anterior fossa and the total head for this patient group. The anterior fossa volume is of interest due to being the volume in the affected region of the head. We compare these volume changes in CT-scans with a reference group of children that did not undergo this surgery.
Section snippets
Materials and methods
Since December 2010 we have used 3D photography in our craniosynostosis follow-up using a 3DMDhead System (3dMD Limited, London United Kingdom) in RadboudUMC, Nijmegen, the Netherlands. In our follow-up database we selected all 3D photos of children that underwent endoscopically assisted metopic craniosynostosis surgery with helmet therapy that had a pre-surgery 3D photo and at least one post-surgery 3D photo. 26 patients were identified that met these criteria, of which we evaluated the head
Volume analysis
The mean total and mean anterior head volumes above the sella turcica-nasion plane of the 3D photos can be seen in [Table 3] and [Fig. 2]. The mean total volume starts at 942 ml and increases to 1846 ml (96.0% incline). The mean anterior volume starts at 308 ml and increases to 664 ml (116.0% incline). The volumes are based on the outer skin layer as observed by the 3D camera.
The mean total and mean anterior head volumes above the sella turcica-nasion plane of the CT-scans can be seen in [
Discussion
With the use of the CCFP and 3D photos it is possible to perform a longitudinal radiation free follow-up of head shape and volume. The current population on which this was performed consisted of patients that underwent endoscopically assisted metopic suture craniosynostosis surgery. We started in December 2010 to create full head 3D photos of children with craniosynostosis pre- and post-surgery over time. So far only 27 patients could be used in the follow-up with a total of 86 usable 3D photos
Conclusion
We performed a retrospective study to evaluate the head shape and volume changes over time after endoscopically assisted metopic craniosynostosis surgery. We have been able to analyze the volume changes over time above the sella nasion plane thanks to the use of the CCFP (De Jong et al., 2015). The mean total and anterior head volume growth pattern was almost equal to the reference group. A total mean volume increase of 96.0% and an anterior mean increase of 116.0% was observed in the surgery
References (23)
- et al.
The computed cranial focal point
J Craniomaxillofac Surg
(2015) - et al.
Objectification of cranial vault correction for craniosynostosis by three-dimensional photography
J Craniomaxillofac Surg
(2012) - et al.
Endoscopic craniectomy for early correction of craniosynostosis
Plast Reconstr Surg
(1999) Cranial base development: a follow-up x-ray study of the individual variation in growth occurring between the ages of 12 and 20 years and its relation to brain case
Am J Orthod
(1955)- et al.
Creating a normative database of age-specific 3D geometrical data, bone density and bone thickness of the developing skull: a pilot study
J Neurosurg Pediatr
(2015) - et al.
Intracranial pressure and intracranial volume in children with craniosynostosis
Plast Reconstr Surg
(1992) - et al.
Intracranial volume and whole brain volume in infants with unicoronal craniosynostosis
Cleft Palate Craniofacial J
(2011) Endoscopic-assisted treatment of trigonocephaly
Childs Nerv Syst
(2012)- et al.
Endoscopic craniectomy for early surgical correction of sagittal craniosynostosis
J Neurosurg
(1998) - et al.
Variations of endoscopic and open repair of metopic craniosynostosis
J Craniofac Surg
(2009)