To Burr or Not to Burr: Preventing Unintended Fractures During Cranial Vault Reshaping.

Purpose: This study evaluates whether burr holes reduce fracture risk during craniosynostosis surgery by examining their effect on stress distribution at osteotomy endpoints.

Methods: Sixteen macaque calvaria samples (mean age: 8.5 years) were sectioned into 30 × 19 mm pieces. The experimental group (n=8) included burr holes at osteotomy endpoints; the control group (n=8) did not. Finite element analysis optimized osteotomy and fixture hole placement. Mechanical testing utilized an MTS® 30/G universal testing machine. Groups were compared via independent samples t test.

Results: The addition of burr holes did not significantly affect load-bearing capacity or displacement of the specimens. Mean peak load was 70.85 N (SD 22.30) in the burr-hole group versus 69.73 N (SD 20.12) in the control group (P=0.9175). Mean displacement was identical at 1.26 mm (burr-hole SD 0.27 mm; control SD 0.38 mm; P=0.9924). Fracture toughness (Kc) was also comparable between groups: burr-hole 583.1 kJ/m² (SD 165.6) versus control 584.7 kJ/m² (SD 147.9) (P=0.9840).

Conclusion: Burr holes did not significantly impact load-bearing capacity, displacement, or fracture toughness in macaque calvarial bone, contrasting with isotropic materials (eg, steel) where stress relievers reduce fracture risk. Future research should explore alternative stress-relief osteotomy designs to minimize intraoperative fracture risks.