Risk score for early prognostication of aseptic bone flap necrosis

Purpose

Aseptic bone flap necrosis (ABFN) is a common complication of autologous cranioplasty that often requires reoperation. This study aimed to create a risk score for ABFN using relevant demographic, clinical, and laboratory markers.

Methods

We included all patients who underwent autologous cranioplasty after decompressive surgery between 2007 and 2019. We collected laboratory data, initial clinical diagnoses, and demographic parameters before autologous bone flap reimplantation. The significant predictors of ABFN identified in the final multivariate analysis were used to develop a risk score.

Results

Of the 412 patients who underwent craniectomy, 58 (14%, 32 females: 55.2%) developed ABFN. The following independent predictors of ABFN were included in the risk score (0–7 points): craniectomy due to trauma or hemorrhagic stroke (2 points), younger age (< 40 years, 2 points), cranioplasty timing (> 95 days post-craniectomy, 1 point), glutamate-pyruvate transferase < 18 U/L (1 point), and serum creatinine level < 0.815 mg/dL (1 point). The ABFN rates in patients with scores of 0–2, 3–4, and 5–7 points were 4.2%, 16.1%, and 34.6%, respectively. The risk score demonstrated moderate diagnostic accuracy for predicting ABFN, with an area under the curve of 0.739.

Conclusion

The proposed risk score may help in early identification of individuals prone to ABFN. These data suggest that future studies should investigate the significance of metabolic syndromes related to ABFN occurrence. Understanding the potential impact of metabolic factors on ABFN can enhance risk assessment and targeted preventive measures for patients undergoing cranioplasty procedures.