Cranioplasty complications following wartime decompressive craniectomy
Authors: Stephens Frederick L. , Mossop Correy M. , Bell Randy S. , Tigno Teodoro , Rosner Michael K. , Kumar Anand , Moores Leon E. , Armonda Rocco A. 
Published: February 2011

Object
In support of Operation Iraqi Freedom (OIF) and Operation Enduring Freedom-Afghanistan (OEF-A), military neurosurgeons in the combat theater are faced with the daunting task of stabilizing patients in such a way as to prevent irreversible neurological injury from cerebral edema while simultaneously allowing for prolonged transport stateside (5000–7000 miles). It is in this setting that decompressive craniectomy has become a mainstay of far-forward neurosurgical management of traumatic brain injury (TBI).
As such, institutional experience with cranioplasty at the Walter Reed Army Medical Center (WRAMC) and the National Naval Medical Center (NNMC) has expanded concomitantly. Battlefield blast explosions create cavitary injury zones that often extend beyond the border of the exposed surface wound, and this situation has created unique reconstruction challenges not often seen in civilian TBI. The loss of both soft-tissue and skull base support along with the need for cranial vault reconstruction requires a multidisciplinary approach involving neurosurgery, plastics, oral-maxillofacial surgery, and ophthalmology. With this situation in mind, the authors of this paper endeavored to review the cranial reconstruction complications encountered in these combat-related injuries.

Methods
A retrospective database review was conducted for all soldiers injured in OIF and OEF-A who had undergone decompressive craniectomy with subsequent cranioplasty between April 2002 and October 2008 at the WRAMC and NNMC. During this time, both facilities received a total of 408 OIF/OEF-A patients with severe head injuries; 188 of these patients underwent decompressive craniectomies in the theater before transfer to the US. Criteria for inclusion in this study consisted of either a closed or a penetrating head injury sustained in combat operations, resulting in the performance of a decompressive craniectomy and subsequent cranioplasty at either the WRAMC or NNMC. Excluded from the study were patients for whom primary demographic data could not be verified. Demographic data, indications for craniectomy, as well as preoperative, intraoperative, and postoperative parameters following cranioplasty, were recorded. Perioperative and postoperative complications were also recorded.

Results
One hundred eight patients (male/female ratio 107:1) met the inclusion criteria for this study, 93 with a penetrating head injury and 15 with a closed head injury. Explosive blast injury was the predominant mechanism of injury, occurring in 72 patients (67%). The average time that elapsed between injury and cranioplasty was 190 days (range 7–546 days). An overall complication rate of 24% was identified. The prevalence of perioperative infection (12%), seizure (7.4%), and extraaxial hematoma formation (7.4%) was noted. Twelve patients (11%) required prosthetic removal because of either extraaxial hematoma formation or infection. Eight of the 13 cases of infection involved cranioplasties performed between 90 and 270 days from the date of injury (p = 0.06).

Conclusions
This study represents the largest to date in which cranioplasty and its complications have been evaluated in a trauma population that underwent decompressive craniectomy. The overall complication rate of 24% is consistent with rates reported in the literature (16–34%); however, the perioperative infection rate of 12% is higher than the rates reported in other studies. This difference is likely related to aspects of the initial injury pattern—such as skull base injury, orbitofacial fractures, sinus injuries, persistent fluid collection, and CSF leakage—which can predispose these patients to infection.