ICU Journal Club – Craniotomy vs Decompressive Craniectomy in Acute SDH

Decompressive Craniectomy versus Craniotomy for Acute Subdural Hematoma

Hutchinson PJ, et al. The RESCUE-ASDH Trial Collaborators. Decompressive Craniectomy versus Craniotomy for Acute Subdural Hematoma. N Engl J Med. 2023 Jun 15;388(24):2219-2229

Blog written by Dr Jose Chacko 

Introduction

Acute subdural hematomas occur in nearly two-thirds of patients with traumatic brain injury and are associated with poor functional recovery and relatively high mortality (1). An acute subdural hematoma is evacuated through a large craniotomy. The surgeon raises a skull flap to enable access and removal of the hematoma (2). Replacement of the bone flap is usually based on clinical judgment. If the brain swelling is extreme, it may not be possible to replace the bone flap during evacuation. The replacement may also be deferred if there are additional lesions in the brain, including contusions or hemorrhage, that may lead to brain swelling in the postoperative period. The decision of whether to replace the skull flap or not is important; leaving the skull open necessitates cranioplasty later on and adds to the risk of complications (3). Pre-emptive decompressive craniectomy (withholding replacement of the bone flap based on clinical judgment) has not been systematically studied.

The RESCUE-ASDH trial compared outcomes following craniotomy and replacement of the bone flap at the same sitting compared with leaving the skull open with cranioplasty at a later date (pre-emptive decompressive craniectomy) in adult patients following traumatic acute subdural hematoma.

Population and design

The RESCUE-ASDH was a multicenter randomized controlled trial (RCT) in patients with traumatic brain injury who had sustained acute subdural hematoma. The study was conducted between September 2014 to April 2019 across 40 centers in 11 countries, including the UK, India, Canada, Malaysia, Germany, Spain, US, Australia, Hungary, Pakistan, and Singapore. Patients older than 16 years with acute subdural hematoma on the CT scan that required evacuation through a large bone flap either by craniotomy or decompressive craniectomy were included. Patients with other lesions, including contusions and intracerebral hematoma, were also included. Patients could be included regardless of the time elapsed after the injury.

Randomization was in blocks of 4 with assignment in a 1:1 ratio to the craniotomy or the decompressive craniectomy group. Randomization was stratified based on age, geographic region, severity of injury, and CT findings.

Excluded

The study excluded patients with bilateral subdural hematoma, both warranting evacuation. Those with severe co-morbidities and expected to have a poor outcome despite recovery from traumatic brain injury were also excluded.

Procedure

Under general anesthesia, the neurosurgeon raised a bone flap ≥11 cm, opened the dura, and evacuated the hematoma. Other mass lesions, including hematomas or contusions, were evacuated based on the surgeon’s discretion. The bone flap was not replaced if the brain appeared swollen, and replacement appeared likely to cause compression; these patients were excluded from the study. Following evacuation of the subdural hematoma, randomization was carried out – to the craniotomy or decompressive craniectomy groups.

Decompressive craniectomy group

In this group, the skull flap was not replaced; the dura was either left open or a non-constricting duraplasty was performed. Reconstruction of the craniectomy – either with titanium or the autologous bone flap was performed according to local practice.

Craniotomy group

The bone flap was replaced and fixed to the skull all around with an appropriate fixation system, followed by closure of the scalp. Decompressive craniectomy could be performed in patients who underwent a craniotomy initially if they deteriorated later in the postoperative period.

Common management in both groups

The type of incision, dural closure technique, use of drains and ICP monitors, and the method of scalp closure were at the discretion of the surgeon. Other aspects of patient care were based on institutional guidelines.

Sample size

The original sample size was revised after the enrolment of 200 patients. The revised sample size was based on a difference of 14 percentage points in the number of patients with a Glasgow Outcome Scale-Extended (GOSE, table 1) score of 4 or better at 12 months of follow-up. A sample size of 440 patients provided the study with >90% power on ordinal analysis and >80% power on binary analysis.

Table 1. The Glasgow Outcome Scale – Extended (GOSE)

Results

Among 3566 patients who were screened, 2697 patients were excluded for various reasons. A total of 462 were randomized; 407 patients were included in an observational study (not reported in the present study). There were 228 patients assigned to the craniotomy group and 222 patients to the decompressive craniectomy group (Figure 1). The mean age of patients in the craniotomy group was 48.3 years compared to 48.8 years in the decompressive craniectomy group. The severity of injury based on the GCS, presence of other injuries, and co-morbidities were similar in both groups. CT findings were similar in both groups. The median size of the bone flap was 13 (IQR: 12 to 14) cm in both groups.

The primary outcome

There was no significant difference in the primary outcome – the neurological condition based on the GOSE scores at 12 months. The common odds ratio for various categories of outcomes based on the GOSE score for the craniotomy group compared with the decompressive craniectomy group was 0.85, 95% CI: 0.6–1.18 (p = 0.32). Patients with outcomes in the upper severe category or better (considered a good outcome) were 49.8% in the craniotomy group compared with 45.5% in the decompressive craniectomy group. The odds ratio for unfavorable outcomes (GOSE category of lower severe or worse) with craniotomy was 0.77, 95% CI: 0.53 to 1.14. Post hoc sensitivity analysis accounting for missing data revealed similar findings.

Approximately one in three patients in both groups died within 12 months of surgery.

Secondary outcomes

At 6 months, the neurological outcome based on the GOSE score was similar in both groups by ordinal analysis (common odds ratio, 0.84; 95% CI, 0.59 to 1.18). Mortality at 30-days, 6 months, and 12 months was also similar. The median ICU length of stay was 10 days in both groups. Additional cranial surgery was performed more often in the craniotomy group 14.6% vs. 6.9%. The most frequent additional procedure (18/28) in the craniectomy group was decompressive craniectomy. Key outcomes are summarized in Table 2.

Table 2. Key outcomes

Adverse events

Procedure-related adverse events were similar in both groups. The decompressive craniectomy group had a higher incidence of wound complications, including surgical site infection. Non-cranial adverse events were similar in both groups.

Study conclusions

In patients with traumatic brain injury with acute subdural hematoma, the level of disability and quality of life were similar with craniotomy or decompressive craniectomy. Additional surgery, mostly decompressive craniectomy, was performed among more patients in the craniotomy group, while wound-related complications occurred more often in the decompressive craniectomy group.

Strengths

• Multicenter, randomized controlled trial across 11 countries offers good external validity.
• Objective criteria were used to assess outcomes
• Long-term outcomes – at 6 and 12 months were assessed

Limitations

• Blinding was not feasible and could have led to bias. However, the outcomes were adjudicated by personnel unaware of the group assignment.
• Although 3566 patients were screened, only 462 (13%) underwent randomization. The exclusion of a large number of patients reduces the generalizability of the study.
• Thirteen patients in the decompressive craniectomy group and 11 patients in the craniotomy group were lost to follow-up.
• Follow-up was carried out by questionnaire or telephonic interview; a physical examination was not performed, which could affect the validity of the outcomes studied.
• Twenty patients (8.8%) assigned to the craniotomy group underwent decompressive craniectomy; 12 (5.4%) in the decompressive craniectomy group underwent craniotomy.
• ICP monitoring was carried out based on surgeon discretion. However, there is no information regarding the ICP levels. Would decompressive craniectomy benefit subgroups of patients with intracranial hypertension at baseline?

References

1. Bullock MR, Chesnut R, Ghajar J, Gordon D, Hartl R, Newell DW, et al. Surgical management of acute subdural hematomas. Neurosurgery. 2006 Mar;58(3 Suppl):S16-24; discussion Si-iv.
2. Kolias AG, Kirkpatrick PJ, Hutchinson PJ. Decompressive craniectomy: past, present and future. Nat Rev Neurol. 2013 Jul;9(7):405–15.
3. Henry J, Amoo M, Murphy A, O’Brien DP. Complications of cranioplasty following decompressive craniectomy for traumatic brain injury: systematic review and meta-analysis. Acta Neurochir (Wien). 2021 May;163(5):1423–35.