The Incidence of Neurologic Susceptibility to a Skull Defect

To determine whether there is a measureable change in neurologic function after cranioplasty.

This is a prospective single-surgeon, single-center study. Fifty patients who required a cranioplasty procedure were assessed neurologically within 72 hours before and 7 days after surgery. The assessment tools were the Functional Independence Measure (FIM) and the Cognitive assessment report (Cognistat). The scores for both assessments were calculated and then compared before and after surgery.

FIM assessment was performed on all fifty patients, and a Cognistat assessment was performed on 47 patients. Most improvements were seen in the Cognistat scores; however, there appeared to be no specific areas in which there was consistent improvement. There were substantial improvements in the Cognistat assessment in 9 patients. One patient had a much-improved FIM assessment (improved from 18 to 34), but a Cognistat assessment was not possible because of poor neurologic function. These results suggested that improvements after cranioplasty were more likely to occur in the domain of cognitive function than motor function, although overall these results did not reach statistically significance. Bifrontal (vs. unilateral) cranioplasty, timing between decompression and cranioplasty, and age of the patients did not appear to affect the postoperative FIM scores, after we adjusted for preoperative FIM scores and surgical complications.

A small but significant number of patients appear to improve clinically after cranioplasty. Neurologic susceptibility to a skull defect may be more common than had been appreciated previously.