Extended experience in parieto-occipital expansion surgery by meander technique-clinical and radiological evaluation

Abstract

Introduction: Brachycephaly and anterior and posterior plagiocephaly appear as an isolated entity or manifest in syndromic conditions. In severe cases, possible treatment options currently comprise either cranioplasty or osteogenetic distraction. The aim of this paper is to retrospectively review the perioperative course of a series of children treated by posterior meander expansion technique at our institution with focus on the course of postoperative intracranial volume and eventual tonsillar descent evolution.

Methods: Forty-two children received a posterior cranial vault remodeling by means of a posterior meander technique during a 7-year period. Hospital records were reviewed, and pre- and postoperative MRIs were analyzed for intracranial volume, cephalic and asymmetry index, and tonsillar position over time.

Results: Median age at surgery was 11.5 months (range 17 days-10 years). Nineteen children had a symmetrical cranial deformity, twenty-three an asymmetrical synostosis. Half of the cohort showed a syndromic condition. Transfusions were administered in the majority (92.2%) of the cases. A significant postoperative increase of intracranial volume was present from 1188.9 ± 370.4 cm³ to 1324.8 ± 352.9 cm³ (p < 0.001). The asymmetry index showed a significant improvement postoperatively: 0.86 ± 0.06 versus 0.91 ± 0.05 (p < 0.001), while the cephalic index showed a non-statistical change (0.91 ± 0.11 versus 0.88 ± 0.08). Tonsillar herniation, bilateral or homolateral, showed no significant changes at early control, while a nonsignificant amelioration of tonsillar descent was seen among children older than 12 months at late imaging follow-up.

Conclusion: Among the osteoplastic techniques, the posterior meander technique offers several advantages, such as early mobilization of the child, less bony defects, absence of implants, and a small complication rate. However, further comparative studies among different surgical techniques are needed.

Keywords: Brachycephaly; Pansynostosis; Parieto-occipital remodeling; Posterior cranial expansion; Posterior plagiocephaly.

Fig. 1

Intraoperative representative images. A Preoperative registration by the navigation system. B The sinus anatomy is depicted on the skin after registration. C Intraoperative identification of the sinus location on the bone by pointer navigation. D Meander shape bone incision and suboccipital as well as parietal barrel stave incisions. E View from posterior after fixation of the bone by distracting the bone fingers and applying ligation sutures at the edges accordingly. F View from above, indicating the volume gain by expansion

Fig. 2

Correlation between tonsillar position change and time of imaging after surgery at late follow up (R² = 0.3; p = 0.008)

Fig. 3

Representative examples before and after posterior meander expansion technique. A A 5 month-old boy with combined sagittal and bilateral lambdoid suture synostosis (“Mercedes Benz” synostosis) before and after surgery indicating lateral 3D photography and sagittal MR imaging. The patient had no previous surgery and received no further surgeries during follow up. B A 9.5-year-old boy, who received total cranial vault remodeling at another institution during infancy. After posterior meander expansion the posterior cranial vault is showing an improved curvature with improved tonsillar descent after surgery. No further surgery was needed in this patient. C Relative volume gain after posterior meander expansion achieving 26.9 ± 4.6% in the entire cohort. Before 2018, the volume gain was non-significantly lower (23.6 ± 6%) compared to the cohort operated after January 2018 (32 ± 6.7%; values are given as mean ± standard error of mean)