Analysis of the factors affecting graft infection after cranioplasty

The predictors of graft infection after cranioplasty (GIC) following decompressive craniectomy are not well established. Knowledge of the risk factors for GIC will allow development of preventive measures designed to reduce infection rates. Therefore, the objective of this study was to identify risk factors for the development of GIC.

A total of 85 patients underwent reconstructive cranioplasty after decompressive craniectomy between January 2009 and July 2011 and had a follow-up period of > 1 year; charts were reviewed retrospectively. Although autograft was used whenever possible, artificial bone was used for cranioplasty. GIC was defined as infection requiring removal of the bone graft.

GIC occurred in six patients (7.05 %). GIC was not related to the indications for craniectomy, the interval of cranioplasty, graft material, or the size of the bone defect (p = 0.433, p = 0.206, p = 0.665, and p = 0.999, respectively). The GIC rate was significantly related to previous temporalis muscle resection, preoperative subgaleal fluid collection, operative times > 120 min, and postoperative wound disruptions (p = 0.001, p < 0.001, p = 0.035, and p = 0.016, respectively). Multiple logistic regression showed that the presence of a subgaleal fluid collection before cranioplasty significantly increased the risk of GIC (OR: 38.53; 95 % CI: 2.77-535.6; p = 0.006).

The results of this study suggest that long operative times (> 120 min), craniectomy with temporalis muscle resection, the presence of preoperative subgaleal fluid collection, and postoperative wound disruption may be risk factors for graft infection after cranioplasty. Surgical techniques should be developed to reduce operative time and to avoid temporalis muscle resection when possible. In addition, meticulous dural closure aimed at reducing the formation of subgaleal fluid collection is important for the prevention of graft infections after cranioplasty.