Factors prognosticating the outcome of decompressive craniectomy in severe traumatic brain injury: A Malaysian experience

OBJECTIVE: The objective of this prospective cohort study was to analyse the characteristics of severe Traumatic Brain Injury (TBI) in a regional trauma centre Hospital Kuala Lumpur (HKL) along with its impact of various prognostic factors post Decompressive Craniectomy (DC). MATERIALS AND METHODS: Duration of the study was of 13 months in HKL. 110 consecutive patients undergoing DC and remained in our centre were recruited. They were then analysed categorically with standard analytical software. RESULTS: Age group have highest range between 12-30 category with male preponderance. Common mechanism of injury was motor vehicle accident involving motorcyclist. Univariate analysis showed statistically significant in referral area (P = 0.006). In clinical evaluation statistically significant was the motor score (P = 0.040), pupillary state (P = 0.010), blood pressure stability (P = 0.013) and evidence of Diabetes Insipidus (P < 0.001). In biochemical status the significant statistics included evidence of coagulopathy (P < 0.001), evidence of acidosis (P = 0.003) and evidence of hypoxia (P = 0.030). In Radiological sector, significant univariate analysis proved in location of the subdural clot (P < 0.010), location of the contusion (P = 0.045), site of existence of both type of clots (P = 0.031) and the evidence of edema (P = 0.041). The timing of injury was noted to be significant as well (P = 0.061). In the post operative care was, there were significance in the overall stability in intensive care (P < 0.001), the stability of blood pressure, cerebral perfusion pressure, pulse rates and oxygen saturation (all P < 0.001)seen individually, post operative ICP monitoring in the immediate (P = 0.002), within 24 hours (P < 0.001) and within 24-48 hours (P < 0.001) period, along with post operative pupillary size (P < 0.001) and motor score (P < 0.001). Post operatively, radiologically significant statistics included evidence of midline shift post operatively in the CT scan (P < 0.001). Multivariate logistic regression with stepwise likelihood ratio (LR) method concluded that hypoxia post operatively (P = 0.152), the unmaintained Cerebral Perfusion Pressure (CPP) (P = 0.007) and unstable blood pressure (BP) (P = <0.001). Poor outcome noted 10.2 times higher in post operative hypoxia [OR10.184; 95% CI: 0.424, 244.495]. Odds of having poor outcome if CPP unmaintained was 13.8 times higher [OR: 13.754; CI: 2.050, 92.301]. Highest predictor of poor outcome was the unstable BP, 32 times higher [OR 31.600; CI: 4.530, 220440]. CONCLUSION: Our series represent both urban and rural population, noted to be the largest series in severe TBI in this region. Severe head injury accounts for significant proportion of neurosurgical admissions, resources with its impact on socio-economic concerns to a growing population like Malaysia. This study concludes that the predictors of outcome in severe TBI post DC were postoperative hypoxia, unmaintained cerebral perfusion pressure and unstable blood pressure as independent predictors of poor outcome. Key words: Decompressive craniectomy, prognostication of decompressive craniectomy, prognostication of severe head injury, prognostication of traumatic brain injury, severe head injury, severe traumatic brain injury, traumatic brain injury.