Reconstruction of cranial vault defect with polyetheretherketone implants

OBJECT: Reconstruction of a cranial vault defect is a frequent challenge in neurosurgery. Polyetheretherketone (PEEK) is used in many types of prostheses and has been employed for 10 years in our institution (University Hospital of Toulouse, France). The objectives of this study are to describe the benefits and drawbacks of reconstructing the cranial vault defect with a PEEK prosthesis. METHODS: Clinical data of the 37 patients who received a reconstruction with a custom-made PEEK prosthesis from 2007-2015 were retrospectively analysed. Operative technique, postoperative complications, and patient's satisfaction with the aesthetic result-on a scale ranging from 1 (very dissatisfied) to 5 (very satisfied)-were studied. RESULTS: Average follow-up was 4.3 years (from 2 months-9 years). The placement of the prosthesis was performed 195 days on average (from 0-1051 days, standard deviation 258 days) after the initial bone flap removal. One infection (2.7%), which required the removal of the prosthesis, was described. Six patients (16%) were reoperated by the maxillofacial surgery team to treat a lack of temporal projection related to muscle atrophy, using a fat cell autograft taken from the abdominal region. Overall, 30 patients (81%) answered the question about their aesthetic satisfaction, with good results on the satisfaction scale (average 4.5; from 3-5). CONCLUSION: The use of a PEEK prosthesis in cranial vault defect reconstruction is a reliable technique with a high patient satisfaction rate and few complications. Corrections of the temporal muscle atrophy by fat grafting may be performed in addition, without increasing the rate of complications

Mechanical properties of fused sagittal sutures in scaphocephaly

Background: Craniosynostosis in newborns is caused by the premature closure of the cranial sutures leading to cranial vault deformity. It results in aesthetic imbalance and developmental disabilities and surgery is frequent during the first months of growth. Our study focused on scaphocephaly defined as the premature closure of the sagittal suture. We hypothesised that the effective mechanical properties of sutures were altered as compared to those of the parietal adjacent tissue considered as control. Methods: The population consisted of seven males and four females (mean age 4.9 months). Sixteen suture samples and thirty-four parietal tissue samples were harvested during corrective surgery and investigated by using three-point bending tests to obtain the structure-stiffness of specimens. An energy model was used to derive the effective Young’s modulus. A histological study complemented the experimental protocol. Findings: Fused sutures were thicker than adjacent bone and the natural curvature of sutures did not influence the static mechanical response. The stiffness of stenotic sutures was significantly higher than that of the parietal bone. The effective Young’s modulus of stenotic sutures was significantly lower than that of the parietal adjacent tissue. The parietal tissue showed a parallel bone architecture whereas the central stenotic tissue was disorganised with more vascularisation. Interpretation: The stenotic suture differed in structural and mechanical terms from the adjacent bone during calvarial growth in the first year of life. Our study emphasised the alteration of effective tissue properties in craniosynostosis. Keywords: scaphocephaly, craniosynostosis, biomechanics, mechanobiology, paediatrics, morphogenesis