A systematic review of mortality and long-term functional outcomes after decompressive craniectomy for acquired brain injury: The missing rehabilitation reporting.

Background: Decompressive craniectomy (DC) is a surgical procedure for refractory intracranial hypertension following severe acquired brain injury (sABI) and is an effective, life-saving treatment. However, there is significant controversy regarding its impact on long-term functional outcome. Furthermore, the role of postoperative rehabilitation in shaping recovery after DC has been largely overlooked in the literature. Objectives: To systematically review randomized controlled trials (RCTs) evaluating the long-term functional outcomes of DC in patients with sABI, stratified by underlying etiology, with particular attention to the assessment tools employed, their alignment with the International Classification of Functioning, Disability and Health (ICF) framework, and the reporting of post-operative rehabilitation data. Methods: We searched PubMed and Scopus for all RCTs related to DC published between 2000 and 2024. Eligible studies included adults (≥18 years) who underwent DC for acute brain injury and reported at least one functional outcome measure (GOS-E, mRS, GOS, or Barthel Index). Outcomes were dichotomized into favorable and unfavorable categories. A narrative summary was performed because of the substantial clinical and methodological heterogeneity. Results: We included 16 RCTs (1803 participants) in our analysis. The etiologies included traumatic brain injury, intracerebral hemorrhage, acute subdural hematoma, and malignant cerebral infarction. DC was associated with lower overall mortality compared to those not receiving it (24% vs. 31%). However, in 8 RCTS, a higher proportion of patients with DC had unfavorable functional outcomes. All outcome scales mapped exclusively to the ICF domain of "Activities and Participation", while any assessment of cognitive function, emotional well-being, social participation, or quality of life was reported. Rehabilitation was largely unmeasured rather than necessarily absent: Only one study reported any rehabilitation data, limited to the number of patients admitted to inpatient rehabilitation. Most RCTs reported outcomes at 6 months or before; only one RCT extended the follow-up period to 24 months. Conclusions: DC is an effective, life-saving procedure that reduces mortality and has an etiology-dependent effect on functional outcomes. Available functional outcome measures do not adequately capture the multifaceted nature of recovery following severe brain injury. Crucially, the post-DC rehabilitation trajectory is not captured by current trials; this argues for the routine, prospective collection of rehabilitation data in future RCTs to determine the contribution of postoperative rehabilitation to long-term functional recovery rather than against the use of a life-saving procedure.