Analysis of the factors influencing bone graft infection after cranioplasty

BACKGROUND Delayed cranioplasty after decompressive craniectomy was performed using various reconstruction materials and methods. Bone graft infection is a major concern with cranioplasty. This study identified factors that are related to bone graft infection after cranioplasty. METHODS A total of 140 patients underwent reconstructive cranioplasty after decompressive craniectomy between 2000 and 2009. The sample population included 102 male patients and 39 female patients aged 6 years to 76 years, with a mean age of 47.5 years. Autografts were used for cranioplasty when available. Polymethylmethacrylate or customized linear high-density polyethylene was considered when autografts were unavailable. Bone graft infection was defined as the removal of the infected bone graft, and the related factors were evaluated retrospectively. RESULTS Bone graft infection occurred in 11 patients (7.86%). Bone graft infection after cranioplasty was significantly related to the number of operations (p = 0.002), operation time (p = 0.031), and diabetes (p = 0.004). An increased number of operations increased the infection rate from 4.3% to 33%. Infection rates increased rapidly after three times. The infection rate was less than 10% when cranioplasty was completed within 199 minutes. An infection rate greater than 20% was observed when cranioplasty required more than 200 minutes. Other factors, such as graft material, fixation devices, age, sex, the cause of the operation, the interval between craniectomy and cranioplasty, and underlying nondiabetic diseases, did not significantly alter the infection rate. CONCLUSION Short surgical times (<200 minutes) and a lower number of previous operations (less than three times) may decrease the risk of bone flap infection. Careful attention is required when performing cranioplasty, particularly in patients with diabetes. LEVEL OF EVIDENCE Prognostic/therapeutic study, level IV.