Introduction: Craniectomies are performed for a multitude of indications including trauma, refractory intracranial pressure, malignant cerebral edema, vascular procedures, skull tumors and local tumor invasion. This often necessitates subsequent cranioplasty. The need to prevent secondary complications is paramount in this otherwise relatively straightforward second procedure. Complications of cranioplasty include epidural and subdural hematomas and fluid collections and especially infection. Infection rates as high as 15% have been reported. This often leads to removal of the bone flap, long-term intravenous antibiotics, and eventual re-operation for a second cranioplasty. We performed a chart review at a single institution to analyze whether factors associated with cranioplasties are related to post-operative infections.

Methods: Retrospective chart review of cranioplasties was performed at the University of Arizona Medical Center. A Pearson Chi-square test was used to evaluate significant correlations between multiple variables from the chart review and post-operative wound infection. A p-value < 0.05 was considered significant.

Results: Between January 2007 and April 2013, 94 cranioplasties were performed on 82 patients by seven attending neurosurgeons. 73.4% of the patients were male and 63.8% of the procedures were performed after traumatic injuries. 51.1% of the procedures used autologous bone graft stored in a freezer. Post-operative infections occurred in 13.8% of the procedures. There were no correlations found between any of the factors associated with the cranioplasties and post-operative infection. The analyzed variables were autograft v. allograft (p=0.829), surgeon (p=0.679), age > 70 (p=0.290), and traumatic cause of initial craniectomy (p=0.819).

Conclusions: No significant risk factors that increase the rate of post-operative infection following cranioplasty were distinguished. The post-operative infection rate was relatively low and cranioplasty remains a safe procedure. Further research is necessary to elucidate if any elements of cranioplasties can be ameliorated in order to reduce the incidence of post-operative infection.

Patient Care: Cranioplasties have an alarmingly high rate of infection given the relatively straightforward nature of the surgery. This necessitates further research and rectifying of any modifiable risk factors.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of evaluating risk factors for post-cranioplasty infection, 2) Discuss, in small groups, risk factors that increase the incidence of infection following cranioplasty, and 3) Identify an effective method for identifying and amending any modifiable risk factors for infection.

References: 1. Yadla S, Campbell PG, Chitale R, Maltenfort MG, Jabbour P, Sharan AD. Effect of early surgery, material, and method of flap preservation on cranioplasty infections: a systematic review. Neurosurgery. Apr 2011;68(4):1124-1129; discussion 1130. 2. Gooch MR, Gin GE, Kenning TJ, German JW. Complications of cranioplasty following decompressive craniectomy: analysis of 62 cases. Neurosurg Focus. Jun 2009;26(6):E9. 3. De Bonis P, Frassanito P, Mangiola A, Nucci CG, Anile C, Pompucci A. Cranial repair: how complicated is filling a "hole"? J Neurotrauma. Apr 10 2012;29(6):1071-1076. 4. Schuss P, Vatter H, Marquardt G, et al. Cranioplasty after decompressive craniectomy: the effect of timing on postoperative complications. J Neurotrauma. Apr 10 2012;29(6):1090-1095.