DECRA: Decompressive Craniectomy in Traumatic Brain Injury (2011)

“Among patients with severe diffuse traumatic brain injury and refractory intracranial hypertension, early decompressive craniectomy decreased intracranial pressure and the length of stay in the ICU but was associated with more unfavorable outcomes.”

  • The DECRA Trial Investigators

1. Publication Details

  • Trial Title: Decompressive Craniectomy in Diffuse Traumatic Brain Injury
  • Citation: Cooper DJ, Rosenfeld JV, Murray L, et al. Decompressive Craniectomy in Diffuse Traumatic Brain Injury. N Engl J Med. 2011;364(16):1493-1502. DOI: 10.1056/NEJMoa1102077
  • Published: April 21, 2011, in The New England Journal of Medicine
  • Author: D. James Cooper, M.D.
  • Funding: National Health and Medical Research Council of Australia; Victorian Neurotrauma Initiative; and others.

2. Keywords

  • Traumatic Brain Injury (TBI), Decompressive Craniectomy, Intracranial Hypertension, Neurosurgery, Critical Care

3. The Clinical Question

  • In adult patients with severe diffuse traumatic brain injury and refractory intracranial hypertension (Population), does early bifrontotemporoparietal decompressive craniectomy (Intervention) compared to continued standard medical care (Comparison) improve functional outcomes at 6 months (Outcome)?

4. Background and Rationale

  • Existing Knowledge: Decompressive craniectomy, a surgical procedure where a large section of the skull is removed to allow the swollen brain to expand, was known to be a powerful method for lowering dangerously high intracranial pressure (ICP) after traumatic brain injury (TBI). However, it was a major operation with its own risks.
  • Knowledge Gap: Despite its effectiveness in lowering ICP, there was no high-quality evidence from randomized controlled trials to determine if this surgical intervention actually improved long-term, patient-centered outcomes like functional recovery, or if it simply saved patients who would then be left in a state of severe disability.
  • Proposed Hypothesis: The authors hypothesized that early decompressive craniectomy would lead to better functional outcomes (lower rates of death or severe disability) compared to standard medical care alone.

5. Study Design and Methods

  • Design: A multicenter, prospective, randomized, controlled trial (used to test the effectiveness of interventions).
  • Setting: 15 tertiary care hospitals in Australia, New Zealand, and Saudi Arabia.
  • Trial Period: Enrollment ran from December 2002 to April 2010.
  • Population:
    • Inclusion Criteria: Adult patients (15-59 years) with severe, diffuse (no large hematomas) traumatic brain injury and refractory elevated ICP (>20 mm Hg for more than 15 minutes within a 1-hour period) despite initial medical therapies.
    • Exclusion Criteria: Included patients with mass lesions requiring surgery, fixed and dilated pupils, or cardiac arrest before hospital arrival.
  • Intervention: Patients in the surgical group underwent a large, early decompressive craniectomy in addition to ongoing standard medical care.
  • Control: Patients in the standard-care group continued to receive advanced medical management for elevated ICP (including sedation, neuromuscular blockade, and hyperosmolar therapy). Barbiturate coma was the next step if ICP remained elevated.
  • Management Common to Both Groups: All patients were managed according to Brain Trauma Foundation guidelines for severe TBI.
  • Power and Sample Size: The authors calculated that a sample size of 210 patients would be required to have 80% power to detect a 20% absolute difference in the rate of unfavorable outcomes. (Power is a study’s ability to find a real difference between treatments if one truly exists; 80% is the standard accepted level for clinical trials).
  • Outcomes:
    • Primary Outcome: Unfavorable functional outcome at 6 months, defined as a score of 1 to 4 on the Extended Glasgow Outcome Scale (death, vegetative state, or severe disability requiring assistance for daily living).
    • Secondary Outcomes: Included mortality, control of ICP, and length of stay in the ICU.

6. Key Results

  • Enrollment and Baseline: 155 patients were randomized (73 to craniectomy and 82 to standard care). The groups were well-matched at baseline.
  • Trial Status: The trial was stopped early by the data monitoring committee because of concerns about the primary outcome results, despite having not reached the planned sample size.
  • Primary Outcome: Patients in the decompressive craniectomy group had a significantly higher rate of unfavorable outcomes at 6 months (defined as death, a vegetative state, or severe disability requiring assistance for daily living): 51 of 73 patients (70%) in the craniectomy group had an unfavorable outcome, compared with 42 of 82 patients (51%) in the standard-care group (p=0.03).
  • Secondary Outcomes: Decompressive craniectomy was more effective at lowering ICP and resulted in fewer days in the ICU. However, there was no significant difference in the mortality rate between the two groups.
  • Adverse Events: Adverse events were common in both groups, consistent with the severity of the injury. There were no significant differences in the rates of complications such as hypotension, coagulopathy, or pneumonia between the groups.

7. Medical Statistics

  • Analysis Principle: The trial was analyzed using an intention-to-treat principle.
  • Statistical Tests Used: The primary outcome was analyzed using a chi-square test.
  • Primary Outcome Analysis: The primary outcome was a comparison of the proportions of patients with an unfavorable outcome between the two groups.
  • Key Statistic(s) Reported: Odds Ratio (OR) for an unfavorable outcome: 2.21 (95% CI, 1.14 to 4.26; P-value: 0.02).
  • Interpretation of Key Statistic(s):
    • Odds Ratio (OR):
      • Formula: Conceptually, OR = (Odds of Unfavorable Outcome in Intervention Group) / (Odds of Unfavorable Outcome in Control Group).
      • Calculation: The paper reports the adjusted result as 2.21.
      • Clinical Meaning: The OR of 2.21 means that the odds of having an unfavorable outcome (death or severe disability) were more than twice as high in the craniectomy group compared to the standard-care group.
    • Confidence Interval (CI):
      • Formula: Conceptually, CI = (Point Estimate) ± (Margin of Error).
      • Calculation: The 95% CI was 1.14 to 4.26.
      • Clinical Meaning: Since this entire range is above the line of no effect (1.0), it confirms that the result is statistically significant. It suggests that craniectomy is associated with harm in this patient population.
    • P-value: The p-value of 0.02 is below the 0.05 threshold, indicating the result is statistically significant (a result is conventionally considered statistically significant if the p-value is less than 0.05).
  • Clinical Impact Measures:
    • Absolute Risk Increase (ARI):
      • Formula: ARI = (Risk in Intervention Group) – (Risk in Control Group)
      • Calculation: ARI = 70% – 51% = 19%.
      • Clinical Meaning: For every 100 patients treated with early craniectomy, about 19 additional patients had an unfavorable outcome.
    • Number Needed to Harm (NNH):
      • Formula: NNH = 1 / ARI
      • Calculation: NNH = 1 / 0.19 = 5.3, which is rounded down to 5.
      • Clinical Meaning: You would only need to treat 5 patients with early craniectomy to cause one additional unfavorable outcome.
  • Subgroup Analyses: The results were consistent across subgroups.

8. Strengths of the Study

  • Study Design and Conduct: As a multicenter, randomized controlled trial, it provided the first high-quality evidence on this important clinical question, challenging existing dogma.
  • Generalizability: The inclusion of 15 centers across three countries increases the external validity, making the results more applicable to a broad range of clinical settings than a single-center trial.
  • Statistical Power: Although stopped early, the trial had a large enough sample size to detect a statistically significant difference in the primary outcome.
  • Patient-Centered Outcomes: The primary outcome of functional status at 6 months is a robust and highly relevant outcome for patients and families, moving beyond simple physiological markers like ICP.

9. Limitations and Weaknesses

  • Internal Validity (Bias): The study was unblinded. The primary outcome (functional status) was assessed via a structured telephone interview, which can be subjective and prone to bias when the assessor is not blinded to the treatment allocation.
  • External Validity (Generalizability): The trial focused on early craniectomy for diffuse injury, so the results may not apply to patients with focal mass lesions or those who receive the surgery later in their course as a rescue therapy.
  • Other: The trial was stopped early, which can sometimes affect the precision of the results and potentially overestimate the magnitude of the observed effect (in this case, harm). The crossover rate was also notable, as some patients in the standard-care group ultimately received a craniectomy.

10. Conclusion of the Authors

  • In patients with severe diffuse traumatic brain injury and refractory intracranial hypertension, early decompressive craniectomy decreased ICP and ICU stay but was associated with more unfavorable functional outcomes at 6 months.

11. To Summarize

  • Impact on Current Practice: This trial was highly influential and challenged the widespread practice of performing early decompressive craniectomy. It raised the critical concern that while the surgery could save lives, it might be saving them to a state of severe disability that patients and families would not have chosen.
  • Specific Recommendations:
    • Patient Selection: For adult patients with severe, diffuse TBI and refractory ICP.
    • Actionable Intervention: The results argue against the routine use of early decompressive craniectomy in this specific population.
    • Expected Benefit: The intervention was associated with harm (an NNH of 5 for unfavorable outcome).
  • What This Trial Does NOT Mean: This trial does NOT mean that decompressive craniectomy should never be performed; its findings are specific to early craniectomy in patients with diffuse injury.
  • Implementation Caveats: This trial highlights the critical lesson that improving a physiological number (ICP) does not always translate to improved patient-centered outcomes.

12. Context and Related Studies

  • Building on Previous Evidence: The DECRA trial (2011) was the first major RCT to challenge the assumption that lowering ICP with craniectomy would automatically lead to better patient outcomes.
  • Influence on Subsequent Research: The surprising and controversial results of DECRA directly led to the design of the subsequent RESCUEicp trial (2016). RESCUEicp studied a slightly different population (including patients with mass lesions) and used a different surgical technique, and ultimately found that craniectomy did reduce mortality, though a higher proportion of survivors were left with severe disability.

13. Unresolved Questions & Future Directions

  • Unresolved Questions: The DECRA trial did not answer whether a different type of craniectomy or performing the surgery later in the clinical course would be beneficial.
  • Future Directions: The conflicting results between DECRA and RESCUEicp have fueled an ongoing debate. Future research is focused on identifying which specific patients with TBI are most likely to benefit from this major surgery, and which are more likely to be harmed.

14. External Links

15. Framework for Critical Appraisal

  • Clinical Question: The research question was highly relevant, addressing a common and high-stakes intervention for which there was no high-quality evidence.
  • Methods: The multicenter RCT design was appropriate. However, the lack of blinding for the outcome assessment is a significant limitation that could have introduced bias. The specific surgical technique and the timing of the intervention are also key factors that limit the generalizability of the findings to all forms of decompressive craniectomy.
  • Results: The primary outcome was statistically significant and showed a clinically important increase in harm (NNH of 5). This surprising result, showing that an intervention could lower a physiological number (ICP) but worsen patient-centered outcomes, was a major finding.
  • Conclusions and Applicability: The authors’ conclusion is a fair reflection of their data. The trial was instrumental in forcing the neurocritical care community to re-evaluate the goals of ICP management, shifting the focus from simply lowering a number to improving long-term functional recovery.

16. Disclaimer and Contact

  • This summary is provided by the Academic Committee of ESBICM (ACE) to facilitate the understanding of this study; readers are advised to refer to the original trial document for a deeper understanding. If you find any information incorrect, or missing, or it needs an update or have a request for a specific critical care trial summary, kindly write to us at academics[at]esbicm.org.
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