Background: Autologous bone continues to represent the first choice for reconstruction of calvarial defects. However, unanswered questions remain on the natural history of the graft and the influence of patient-related risk factors. This study investigated the outcomes of skull reconstruction with split calvarial bone graft, examining the natural history and stratifying the risk of unfavorable results.
Methods: Patients who underwent cranioplasty with split calvarial bone graft between 1982 and 2016 at the Cleveland Clinic were analyzed, recording demographics, comorbidities, indications, size and location of defect, and outcomes including complications and reoperations. Changes in graft thickness were analyzed using computed tomographic and magnetic resonance imaging scans.
Results: Forty-one patients with an average age of 33.2 years, cranial defect size of 68 cm, and mean follow-up of 28 months were included. The majority of patients (85 percent) had significant risk factors, with 43 percent suffering prior infection. Seventy-three percent of patients experienced successful restoration. A major complication was recorded in 26.8 percent; resorption occurred in 19.5 percent of patients (in 75 percent only at the recipient site), with 9.8 percent requiring reoperation. Patients with one or more risk factors or a smoking history were more likely to experience a complication. The mean ratio of the graft to the bicortical donor bone thickness was 0.48 ± 0.17 for the recipient site and 0.57 ± 0.10 for the donor site at an average radiographic follow-up of 11.9 ± 10.9 years.
Conclusions: This study demonstrated a 73.2 percent first-attempt success rate in a high-risk population. The grafts maintain thickness over time, with no evidence of bone hypertrophy. Defect characteristics and patient systemic factors appear to be important variables influencing success.
Clinical question/level of evidence: Therapeutic, IV.