gms | German Medical Science

Objective: In the pediatric age group the technical aspects of decompressive hemicraniectomy have not been systematically analyzed before. Here we present a detailed morphometric analysis of relevant variables to guide optimal surgical technique.

Methods: We retrospectively analyzed all patients younger than 18 years who underwent decompressive hemicraniectomy at our institution since 2010 and for whom pre- and postoperative cranial computed tomography imaging was available. The maximum fronto-occipital skull length was measured as an indicator of age-dependent skull size. The maximum anterior-posterior (A) and cranio-caudal (B) diameters of the hemicraniectomy were measured to calculate the approximate decompression area (A x B). Maximum horizontal brain diameters were measured before (C) and after (D) hemicraniectomy as surrogate parameter of volume gain (D – C).

Results: We analyzed 13 hemicraniectomies in 10 patients (6 boys, 4 girls) with a mean age 13 years (range 5–17 years). The fronto-occipital skull length demonstrated an almost linear correlation with age, although the range was narrow between 14.2 and 17.5cm (Pearson correlation coefficient R=0.8044). Mean maximum anterior-posterior craniectomy diameter was 11.7cm (range 9.4–14.1cm), independent of age (Pearson correlation coefficient R=-0,02). Mean craniectomy area was 12166mm2 (range 7520–15933mm2). The mean postoperative gain in horizontal brain diameter was 1.3cm (range 0.3–2.4cm), with larger measures in the subgroup with poor outcome or death (1.28cm±0.29cm versus 0.70cm±0.07cm, two-sided t-test P=0.0372).

Conclusion: Our analysis suggests that in the pediatric age group represented in this study neurosurgeons should aim for an antero-posterior craniectomy diameter of approximately 12cm, similar to adults. The increase in skull size across this age group was relatively small as head growth is accelerated mainly in the first year of life, thus adapting craniectomy size to age can be neglected beyond infancy. When a large hemicraniectomy is achieved in children, a gain in horizontal brain diameter of more than 1cm might indicate severe brain herniation through the craniectomy defect, which correlates with poor outcome.