The effect of cranioplasty following decompressive craniectomy on cerebral blood perfusion, neurological, and cognitive outcome

Abstract

OBJECTIVE Decompressive craniectomy is an established therapy for refractory intracranial hypertension. Cranioplasty following decompressive craniectomy not only provides protection to the brain along with cosmetic benefits, but also enhances rehabilitation with meaningful functional recovery of potentially reversible cortical and subcortical damaged areas of the affected as well as the contralateral hemisphere. The aim of the study was to assess neurological and cognitive outcome as well as cerebral blood flow after cranioplasty. METHODS Thirty-four patients admitted for replacement cranioplasty after decompressive craniectomy for head injury were studied prospectively. Clinical, neurological, and cognitive outcomes were assessed by the Glasgow Outcome Scale (GOS), the Glasgow Coma Scale, and a battery of cognitive tests, respectively. Simultaneously, cerebral blood perfusion was assessed by technetium-99m ethyl cysteinate dimer (^99mTc-ECD) brain SPECT imaging 7 days prior to and 3 months after cranioplasty. RESULTS Prior to cranioplasty 9 patients (26.5%) had GOS scores of 5 and 25 patients (73.5%) had GOS scores of 4, whereas postcranioplasty all 34 patients (100%) improved to GOS scores of 5. Approximately 35.3%-90.9% patients showed cognitive improvement postcranioplasty in various tests. Also, on comparison with brain SPECT, 94% of patients showed improvement in cerebral perfusion in different lobes. CONCLUSIONS Cranioplasty remarkably improves neurological and cognitive outcomes supported by improvement in cerebral blood perfusion.

Keywords: 99mTc-ECD = technetium-99m ethyl cysteinate dimer; CBF = cerebral blood flow; CBP = cerebral blood perfusion; COWAT = Controlled Oral Word Association Test; DSST = Digit Symbol Substitution Test; DST = Digit Span Test; GCS; GCS = Glasgow Coma Scale; GOS; GOS = Glasgow Outcome Scale; RAVLT-DR, RAVLT-IR = Rey Auditory Verbal Learning Test–delayed recall, RAVLT–immediate recall; SPECT; TMT-A, TMT-B = Trail-Making Test, Parts A and B; cognitive outcome; cranioplasty; decompressive craniectomy; trauma.