Despite the burden of chronic subdural hematomas (CSDH) in neurosurgical services,
the gold standard management of this condition still remains controversial. In 2012,
we conducted a survey with the heads of neurosurgical services bound to the Brazilian
Society of Neurosurgery (Sociedade Brasileira de Neurocirurgia) regarding the treatment strategies of CSDH (n = 49/54, 90%)[1]. The telephone interview comprised 10 closed-ended questions about surgical approach:
craniotomy vs. burr hole craniostomy vs. twist-drill craniostomy; number of burr hole
craniostomies performed, if indicated (one or two); intraoperative irrigation of subdural
cavity or not; use and management of drains (yes or no, duration of drainage); postoperative
patient position (flat vs. elevated head position); duration of bed rest; routine
postoperative cranial image examinations; and use of corticosteroids or anticonvulsants[1].
The survey demonstrated a lack of uniform approach to this common condition in Brazilian
academic neurosurgical institutions. Regarding the surgical approach ([Figure 1]), most of the respondents preferred to use a burr hole craniostomy (85.7%), half
of them opted for one burr hole and the other half opted for two burr holes. Few centers
performed the twist-drill craniostomy (6.1%) or craniotomy (8.2%) as the first option
for treating CSDH. All neurosurgeons interviewed performed irrigation of the subdural
cavity intraoperatively. Regarding postoperative management, the majority of Brazilian
neurosurgical centers preferred to keep the patient's head flat after evacuation of
the hematoma (59.2%), 26.5% preferred the elevated position and 14.3% did not recommend
any specific position after surgery (i.e. the patient's preference). The duration
of bed rest was no longer than two days for 75.5% of respondents. A routine postoperative
computed tomography scan was performed by the majority of respondents (65.3%). Only
one center (2%) reported the use of corticosteroids and 20.4% routinely used prophylactic
anticonvulsants.
Figure 1 Results of the Brazilian national survey with the heads of academic neurosurgical
institutions on the preferred surgical approach for chronic subdural hematoma.
In our survey, it was observed that the majority (83.7%) of Brazilian neurosurgical
programs used a drain after evacuation of the CSDH ([Figure 2]). Most of them left the drain in the subdural (87.8%) or subgaleal space (12.2%).
Concerning the duration of drainage, 26.8% removed the drain in 24 hours, 56.1% in
48 hours, and 17.1% usually left it for more than 72 hours.
Figure 2 Results of the Brazilian national survey with the heads of academic neurosurgical
institutions on (A) use of a drain in the postoperative care for chronic subdural
hematomas, and (B) duration of drainage.
We recently performed a broad systematic review and meta-analysis on the surgical
treatment of CSDH and highlighted the best existing evidence on the subject[2]. Despite the lack of good quality evidence to support most of the commonly-performed
neurosurgical procedures in CSDH, the use of a drain is very well established and
its use is supported by a high quality randomized controlled trial[3]. In 2009, Santarius et al.[3] published a large, high quality, and well-reported randomized controlled trial (RCT)
comparing a drain versus no-drain in CSDH. The trial was stopped by the committee
due to the high level of evidence of benefit from the use of the drain in lowering
the recurrence rate. The long-term analysis of the RCT (five years) showed lower mortality
rates in patients who had received a subdural drain[4].
Surprisingly, in a recent paper published in Arquivos de Neuropsiquiatria
[5], Heringer et al. stated that the use of a drain does not interfere with surgical
outcomes in CSDH. We recognize the importance of retrospective studies in the neurosurgical
literature and congratulate the authors for their efforts. However, we respectfully
disagree with their strict statement that drainage is not associated with better outcomes
in CSDH. Firstly, few questions in neurosurgical practice have been answered by high
quality RCTs. The benefit of drainage in CSDH is one that has[3],[4]. Secondly, their retrospective study clearly presents several drawbacks, including
(but not limited to) the unclear decision whether or not to use a drain (i.e. absence
of randomization), and the obviously underpowered sample to answer this question.
For example, the power analysis of the Santarius et al.[3] trial estimated a sample size of 219 in each group (80% power, alpha = 0.05). Thus,
it is much more likely that the absence of a statistically significant association
between drainage and recurrence/complications reported by Heringer et al. is due to
these relevant drawbacks than a real absence of clinical benefit with drain usage,
as has been already proven with high quality data[3],[4].
Variations in clinical practice regarding most of the procedures performed for CSDH
may be caused by the absence of level I evidence for many practices[2]. Nevertheless, a postoperative drain is used in most Brazilian academic neurosurgical
services (83.7%). In fact, this practice is supported by high-quality neurosurgical
evidence[2],[3],[4]. Another international survey[6] suggested that the use of drains increased after publication of the Santarius et
al.[3] trial. Evidence-based national guidelines may reduce variations in practice among
different centers and improve outcomes in CSDH.
