After completing recruitment of some 408 TBI patients in 2014, the RESCUEicp group finally published the results from this eagerly awaited trial. The article by Hutchinson et al, titled Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension, was published on September 7th in the New England Journal of Medicine. So let´s go straight to the core:
The study reveals a much lower mortality in patients with intractable intracranial hypertension who underwent craniectomy (26.9% at 6 months), compared to those who received medical therapies only (48.9%). However, the survivors were far more likely to end up with poor neurological outcomes (vegetative state or with lower severe disability) at both 6 and 12 months.
RESCUEicp follows in the wake of the DECRA trial, where bifrontal hemicraniectomy for refractory ICP higher than 20 mmHg yielded no survival benefit, and seemed to worsen neurological outcomes. The effect on ICP was, as expected, markedly better in the craniectomy cohort, but this failed to translate into more survivors.
There are a few noteworthy differences between DECRA and RESCUEicp that may have contributed to the diverging results. Firstly, the ICP threshold for intervention was lower in DECRA than in the newer trial (20 mmHg vs. 25 mmHg, respectively). Bifrontal hemicraniectomies were performed in all DECRA-patients who underwent decompressive surgery. The percentage in RESCUEicp was lower at 63%, with the remainder undergoing unilateral craniectomies. In the latter trial the approach was at the discretion of the surgeon. Furthermore, a significant proportion of patients (37%) randomised to the medical arm of RESCUEicp ended up with a “rescue” craniectomy. These were performed in cases where other measures were exhausted and the managing medical team deemed it reasonable. To which degree this deviation from the intended treatment has skewed results is unknown. If anything, it may have offset a greater actual difference in survival somewhat, thereby reducing the perceived benefit of decompressive craniectomy.
RESCUEicp had a more permissive approach allowing ICP >25 mmHg for 1-12 hours. On the other hand, DECRA aimed to evaluate the effect of early decompression, intervening at an ICP>20 mmHg for more than 15 minutes. It could be argued that early surgical intervention at a lower threshold may have subjected a subset of patients, who may not ultimately have needed it, to an unnecessary and potentially harmful procedure. How much this will have influenced results is difficult to gauge.
Median times from randomisation to craniectomy were very similar, with 2.2 hours for RESCUEicp and 2.3 hours for DECRA. Time from injury to randomisation was not specified in the RESCUEicp article.
So what to make of this?
Well, first of all: There is a definite survival benefit to performing a decompressive craniectomy. So, more survivors. That´s what we´ve been looking for. The downside is, obviously, that a very substantial proportion of the survivors gained through surgical decompression suffer worse neurological sequelae than their medically treated counterparts. Four times as many patients are vegetative at 6 months, while roughly 1.5 times as many are dependent on others for care. At 12 months the survival benefit of craniectomy persists, but so does the tendency toward poorer outcomes.
Intuitively, for anyone who has witnessed the reliable and immediate ICP-lowering effect of a decompression, it seems like a logical therapy in the setting of impending herniation and death. However, this study, along with DECRA, does invite some very serious second thoughts given the nature of the sequelae seen in the survivors.
I think this study, although thoroughly valuable and very well carried out, may generate more questions than answers. It will certainly be a topic of discussions for quite some time. How much it will alter practice is still an open question. In the absence of clear-cut advantages in both survival and neurological outcomes, the decision to decompress is likely to remain a difficult one, made on an individual basis. As an aside: It is noteworthy that we are still left with ICP as the key (and in reality, only) parameter guiding vital surgical decisions.
Please comment below. We are keen to hear your interpretation. This is still fresh material and we need help digesting it.
Also worth a read is Medscape´s editorial, which includes comments by lead author Dr. Hutchinson.