Improvement of cerebral blood perfusion in certain cerebral regions after cranioplasty could be monitored via tympanic membrane temperature changes.

Objective: Delayed neurological deficit was often observed in patients underwent craniectomy, which could be improved by cranioplasty. Little is known about hemodynamic improvement before and after cranioplasty. Methods: Cerebral blood perfusion, tympanic membrane temperature (TMT), neuropsychological and cognitive function were assessed in eleven craniectomy patients before and after cranioplasty. Results: Before cranioplasty, the cerebral blood volume (CBV) on the decompressed side was significantly lower than that of the contralateral side. The cranioplasty led to instant improvement (7 days after cranioplasty) of cerebral perfusion at the cranioplasty side in the frontal lobe, parietal lobe, temporal lobe, mesencephalon, basal ganglia and thalamus, but not the occipital lobe and epencephalon. Interestingly, CBV of the thalamus and basal ganglia gradually decreased to pre-surgical status 6 months later while the frontal lobe, parietal lobe, temporal lobe, mesencephalon remained well perfused. Meanwhile, the TMT changes acquired positive correlation with the perfusion of temporal lobe and mesencephalon as well as the GCS and MMSE score. Conclusion: The cranioplasty remarkably improves neurological and cognitive function by ameliorating cerebral perfusion in certain regions. The TMT could be used as a non-invasive method to monitor the cerebral perfusion improvement after the cranioplasty.