Supratentorial vs infratentorial posterior calvarial distraction osteogenesis for the increase of ICV in children with syndromic or multi-suture craniosynostosis: a retrospective cohort study

Jack Sharman,Simon Mcguirk,Steve Dover,Desiderio Rodrigues,Nicholas White,Mohini Panikkar,Hiroshi Nishikawa,Martin Evans

doi:10.1007/s00381-021-05064-4

Abstract

PurposeCraniosynostosis is the premature and pathological fusion of calvarial sutures. One modality of surgical treatment of syndromic craniosynostosis is posterior calvarial distraction (PCD). This can be either supratentorial or infratentorial. Currently, supratentorial PCD may be regarded as safer but produces a smaller increase in calvarial volume compared to infratentorial PCD. This study quantifies and compares the effectiveness of supratentorial and infratentorial PCD to help guide surgical decision-making.MethodsThe CT and/or MRI scans of 47 cases of craniosynostosis who underwent PCD from the Birmingham Children’s Hospital (BCH) were converted to sagittal series multi-planar reformatted (MPR) scans for the manual calculation of ICV. The 47 cases were classified as having undergone either supratentorial or infratentorial PCD using lateral plain film radiographs, with 28 and 32 pairs of pre- and post-operative CT/MRI scans reviewed respectively.ResultsA statistically significant difference between supratentorial and infratentorial PCD was observed for the increase in supratentorial volume (STV) (P = 0.0458) and total intracranial volume (TICV) (P = 0.0437), but not for the increase in infratentorial volume (ITV) (P = 0.0697). The relationship for each volume trended towards convergence but was not achieved before the physical limit of 30 mm distraction had been reached. Intraclass correlation coefficient values for agreement of MRI and CT scans for STV, ITV and total ICV were 0.852, 0.864 and 0.854 respectively.ConclusionOur evidence suggests that supratentorial PCD is more effective for increasing ICV in a clinical setting. CT and MRI imaging modalities are acceptably clinically interchangeable for calculating ICV in craniosynostosis.

Highlights

Craniosynostosis describes the premature fusion of one or more calvarial sutures [1]
The combined CT and MRI data showed that supratentorial posterior calvarial distraction (PCD) was more effective than infratentorial PCD in increasing infratentorial volume (ITV) per millimeter distraction, though this was not statistically significant at the 95% confidence level
The combined data showed that the mean percentage volume increase per millimeter distraction for supratentorial PCD was 1.823%, compared to 0.980% for infratentorial PCD (P = 0.0697) (Fig. 4)

Summary

Introduction

Craniosynostosis describes the premature fusion of one or more calvarial sutures [1]. This leads to craniocephalic disproportion resulting in functional and aesthetic sequelae [2, 3]. Raised intracranial pressure (ICP) manifests as developmental delay, seizures and hind-brain herniation, predominantly in syndromic or multi-suture craniosynostosis [4]. Uncertainty remains regarding how extensive craniosynostosis causes raised ICP. Evidence has shown that before 11 months of age those patients with craniosynostosis and raised ICP have greater ICVs than their age-matched peers [5]. The prevailing theory argues that craniocephalic disproportion causes aberrant venous drainage resulting in raised ICP [2]. Limited expansion at specific calvarial sutures results in asymmetrical skull growth and abnormal head shape [6].

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