Explanted Skull Flaps after Decompressive Hemicraniectomy Demonstrate Relevant Bone Avitality-Is Their Reimplantation...

Area of Science:

• Neurosurgery
• Biomaterials Science
• Histopathology

Background:

• Reimplantation of autologous skull flaps after decompressive hemicraniectomy (DH) faces challenges with high rates of postoperative bone flap resorption (BFR).
• Understanding the viability of stored bone flaps is crucial for optimizing reimplantation outcomes.

Purpose of the Study:

• To histologically assess the cell viability of explanted skull bone flaps stored at different temperatures.
• To determine if precursors of bone flap resorption develop during cryopreservation.

Main Methods:

• Explanted skull bone flaps were cryopreserved at -23°C or -80°C.
• Immunohistochemistry analyzed bone metabolism parameters (PTH1, OPG).
• Hematoxylin and eosin (H&E) staining assessed bone avitality, with repeated assays after 6 months.

Main Results:

• All 17 analyzed skull flaps showed significant bone avitality, which increased after 6 months (p < 0.001).
• Storage at -23°C (p = 0.006) and longer cryopreservation durations (p < 0.001) were linked to increased bone avitality.
• Bone avitality was observed even in flaps stored for several weeks.

Conclusions:

• Storage at -80°C offers a significant advantage for preserving skull bone flap viability.
• Cryopreservation conditions and duration critically impact bone avitality, a potential precursor to BFR.
• The findings necessitate a re-evaluation of the routine reimplantation of autologous skull flaps versus synthetic alternatives.