Decompressive craniectomies: time to discuss not the DECRA study but the comments to the DECRA study

The History of Decompressive Craniectomy in Traumatic Brain Injury

Decompressive craniectomy consists of removal of piece of bone of the skull in order to reduce intracranial pressure. It is an age-old procedure, taking ancient roots from the Egyptians and Romans, passing through the experience of Berengario da Carpi, until Theodore Kocher, who was the first to systematically describe this procedure in traumatic brain injury (TBI). In the last century, many neurosurgeons have reported their experience, using different techniques of decompressive craniectomy following head trauma, with conflicting results. It is thanks to the successes and failures reported by these authors that we are now able to better understand the pathophysiology of brain swelling in head trauma and the role of decompressive craniectomy in mitigating intracranial hypertension and its impact on clinical outcome. Following a historical description, we will describe the steps that led to the conception of the recent randomized clinical trials, which have taught us that decompressive craniectomy is still a last-tier measure, and decisions to recommend it should been made not only according to clinical indications but also after consideration of patients' preferences and quality of life expectations.

The current status of decompressive craniectomy in traumatic brain injury

PURPOSE

This review describes the evidence base that has helped define the role of decompressive craniectomy (DC) in the management of patients with traumatic brain injury (TBI).

RECENT FINDINGS

The publication of two randomized trials (DECRA and RESCUEicp) has strengthened the evidence base. The DECRA trial showed that neuroprotective bifrontal DC for moderate intracranial hypertension is not helpful, whereas the RESCUEicp trial found that last-tier DC for severe and refractory intracranial hypertension can significantly reduce the mortality rate but is associated with a higher rate of disability. These findings have reopened the debate about 1) the indications for DC in various TBI subtypes, 2) alternative techniques (e.g. hinge craniotomy), 3) optimal time and material for cranial reconstruction, and 4) the role of shared decision-making in TBI care. Additionally, the role of primary DC when evacuating an acute subdural hematoma is currently undergoing evaluation in the context of the RESCUE-ASDH randomized trial.

SUMMARY

This review provides an overview of the current evidence base, discusses its limitations and presents a global perspective on the role of DC, as there is growing recognition that attention should also focus on low- and middle-income countries due to their much greater TBI burden.

Decompressive Craniectomy for Traumatic Brain Injury: The Role of Cranioplasty and Hydrocephalus on Outcome

OBJECTIVE

After severe traumatic brain injury (sTBI) associated with uncontrollable high intracranial pressure (ICP), today the main challenge for neurosurgeons remains to identify who may obtain benefit from decompressive craniectomy (DC) and which factors after DC influence the prognosis of these patients. The aim of this paper was to identify the pre- and postoperative determinants of outcome after DC.

METHODS

This retrospective study included all patients undergoing DC for sTBI from 2003 to 2011. The 6-month outcome, assessed using the Glasgow Outcome Scale (GOS), was dichotomized into favorable (GOS scores 4 and 5) and unfavorable (GOS scores 1-3) outcome. Predictors of outcome were identified by uni- and multivariate analysis.

RESULTS

There were 190 patients who underwent DC for sTBI in this study. Sixty patients (31.6%) died within 30 days after DC. Independent prognostic factors for survival after 30 days were Glasgow Coma Scale score at admission greater than 5 (P = 0.002) and bilateral pupil reactivity (P < 0.0001). Thirty days after DC, 67 patients (51.5%) out of 130 had unfavorable outcome (GOS scores 1-3) and 63 patients (49.5%) presented favorable outcome (GOS scores 4 and 5). The independent preoperative prognostic factors for poor outcome were age over 65 years (P < 0.0001) and bilateral absence of pupil reactivity (P = 0.0165). After DC, onset of postoperative hydrocephalus and delayed cranioplasty (3 months after DC) was associated with unfavorable outcome at multivariate analysis (P = 0.002 and P < 0.0001, respectively).

CONCLUSIONS

In our study, the development of hydrocephalus after DC for sTBI and delayed cranial reconstruction were associated with unfavorable outcome.

Paradoxical Brain Herniation After Decompressive Craniectomy Provoked by Drainage of Subdural Hygroma

BACKGROUND

Paradoxical brain herniation (PBH) is a rare and potentially life-threatening complication of decompressive craniectomy (DC) and results from the combined effects of brain gravity, atmospheric pressure and intracranial hypotension causing herniation in the direction opposite to the site of the DC with subsequent brainstem compression. To date, the cases of PBH reported in literature are spontaneous or provoked by a lumbar puncture, a cerebrospinal fluid (CSF) shunt, or ventriculostomy.

CASE DESCRIPTION

We present an uncommon case of PBH provoked by percutaneous drainage of a huge subdural hygroma (SH) ipsilateral to the decompressive craniectomy causing mass effect and neurologic deterioration. After percutaneous evacuation of SH, the patient became unresponsive with dilated and fixed left pupil. A brain computed tomography scan showed marked midline shift in the direction opposite to the craniectomy site with subfalcine herniation and effacement of the peripontine cisterns. Paradoxical brain herniation (PBH) was diagnosed. Conservative treatment failed, and the patient required an emergency cranioplasty for reverse PBH.

CONCLUSIONS

The present case highlights the possibility that all forms of CSF depletion, including percutaneous drainage of subdural CSF collection and not only CSF shunting and/or lumbar puncture, can be dangerous for patients with large craniotomies and result in PBH. Moreover, an emergency cranioplasty could represent a safe and effective procedure in patients not responding to conservative treatment.

The evidence-based medicine paradigm: where are we 20 years later? Part 2

In Part 2, we discuss the challenges of keeping up with the 'literature,' evidence-based medicine (EBM) in emerging economies and the Neurosciences, and two recent approaches to classifying evidence. We conclude by summarizing information from Parts 1 and 2 which suggest the need to critically re-appraise core elements of the EBM paradigm: (1) the hierarchical ranking of evidence, (2) randomized controlled trials or systematic reviews as the gold standard for all clinical questions or situations, (3) the statistical tests that have become integral to the 'measurements' for analyzing evidence, and (4) re-incorporating a role for evidence from basic sciences and pathophysiology. An understanding of how cognitive processes influence clinical decisions is also necessary to improve evidence-based practice. Emerging economies may have to modify the design and conduct of clinical research to their settings. Like all paradigms, EBM must keep improving with input from the grassroots to remain beneficial.