Intracranial Volumes of Healthy Children in the First 3 Years of Life: An Analysis of 270 Magnetic Resonance Imaging Scans.

BACKGROUND: There is a paucity of data on normal intracranial volumes for healthy children during the first few years of life, when cranial growth velocity is greatest. The aim of this study was to generate a normative predictive model of intracranial volumes based on brain magnetic resonance imaging from a large sample of healthy children to serve as a reference tool for future studies on craniosynostosis. METHODS: Structural magnetic resonance imaging data for healthy children up to 3 years of age was acquired from the National Institutes of Health Pediatric MRI Data Repository. Intracranial volumes were calculated using T1-weighted scans with FreeSurfer (version 6.0.0). Mean intracranial volumes were calculated and best-fit logarithmic curves were generated. Results were compared to previously published intracranial volume curves. RESULTS: Two-hundred seventy magnetic resonance imaging scans were available: 118 were collected in the first year of life, 97 were collected between years 1 and 2, and 55 were collected between years 2 and 3. A best-fit logarithmic growth curve was generated for male and female patients. The authors' regression models showed that male patients had significantly greater intracranial volumes than female patients after 1 month of age. Predicted intracranial volumes were also greater in male and female patients in the first 6 months of life as compared to previously published intracranial volume curves. CONCLUSIONS: To the authors' knowledge, this is the largest series of demographically representative magnetic resonance imaging-based intracranial volumes for children aged 3 years and younger. The model generated in this study can be used by investigators as a reference for evaluating craniosynostosis patients.

A Posterior Rotational Flap Technique Using Distraction Osteogenesis for Unilateral Lambdoid Craniosynostosis.

INTRODUCTION: The craniofacial asymmetry seen in unilateral lambdoid craniosynostosis may not be effectively treated by posterior cranial vault remodeling, endoscopic suturectomy, and helmet therapy, or suturectomy and distraction osteogenesis alone due to limitations in soft-tissue envelope expansion and relapse of the deformity. The authors report a series of unilateral lambdoid craniosynostosis patients treated with a posterior rotational cranial-flap technique using internal distraction osteogenesis. METHODS: Posterior cranial vault reconstruction combined with internal distraction was used, aided by preoperative virtual surgical planning. An in situ posterior rotational flap osteotomy was utilized to maximize dural preservation. Primary outcome measures included age-adjusted volume change and age-adjusted percent volume change per mm distraction. Distraction characteristics and perioperative characteristics were also assessed. RESULTS: A total of 5 patients were identified. Mean predistraction intracranial volume was 1087.5 cc (SD  = 202.3 cc) and mean postdistraction included intracranial volume was 1266.1cc (SD  = 131.8cc). Mean age-adjusted percent included intracranial volume change was 14.1% (SD  = 9.6%), and mean percent intracranial volume change per mm distraction was 0.43%/mm distraction (SD  = 0.37%/mm distraction). One patient developed a distractor site infection postoperatively that was treated successfully with oral antibiotics. All patients had a Whitaker score of 1 at one year follow up. CONCLUSIONS: Posterior cranial vault remodeling using osteogenesis and a rotational cranial flap technique with dural preservation can be effectively used to maximize bone flap viability and limit postoperative relapse in patients with unilateral lambdoid craniosynostosis. Long term analysis as well as comparison to open techniques will need to be interrogated.