39. Early Cranioplasty Improves Functional Recovery in a Rodent Traumatic Brain Injury Model

PURPOSE: Cranioplasty is a surgical procedure utilized to reconstruct cranial defects commonly associated with the treatment of traumatic brain injury (TBI) and stroke. Prolonged cranial defects are often the cause of secondary neurologic deficits termed syndrome of the trephined. As such, the timing of cranioplasty has been the subject of long-standing debate in the literature. Using a rat model, the present study aims to assess the impact of early cranioplasty on motor function following TBI. Our hypothesis is that early cranioplasty will contribute to improved functional motor recovery. METHODS: After acclimation, rats were randomized to one of five groups: Group 1 = sham surgery; Group 2 = decompressive hemicraniectomy (DC); Group 3 = TBI & DC; Group 4 = TBI & DC + early cranioplasty; Group 5 = TBI & DC + late cranioplasty. TBI was performed using a controlled cortical impact “hit and run” model, DC was performed with a high-speed drill, and cranioplasty was performed using polycaprolactone plastic cut into the shape of the cranial defect and adhered with acrylic glue. Rat motor function and improvements were measured using a beam walk test with baseline behaviors recorded prior to injury and randomization. Rats were tested at 3 days after their initial surgery and weekly to follow for approximately 1 month. Motor function was assessed via foot slips on each limb and time to cross the beam. Statistical analysis was performed using an unbalanced two-way ANOVA, followed by pairwise comparisons using simple effects analysis. RESULTS: The unbalanced two-way ANOVA revealed significant main effects in the between-subjects analysis for both group and time (p < 0.001). Group 3 (TBI & DC) exhibited significantly more foot slips than Group 1 (sham surgery) at all post-operative time points (p < 0.05). At week 0, Group 3 also performed significantly worse than all other groups (p < 0.05). Group 4 (early cranioplasty) demonstrated significantly fewer foot slips than Group 3 at both week 0 (p < 0.001) and week 2 (p = 0.033). Group 5 (late cranioplasty) showed a significant reduction in foot slips compared to Group 3 only at week 0 (p = 0.013). No significant differences were found between Groups 4 and 5 at any time point, although differences at week 0 approached significance (p = 0.06). CONCLUSION: Early cranioplasty was associated with improved motor function recovery. This study suggests that consideration should be given to performing cranioplasty as early as possible in a clinical setting. Future research may examine means of accelerating the cranioplasty timetable.