Keywords
chronic subdural hematoma - burr hole craniotomy - midline shift - hematoma evacuation
- neurosurgery
Introduction
Chronic subdural hematoma (CSDH) is a prevalent neurosurgical condition characterized
by the accumulation of blood between the dura mater and the arachnoid membrane. It
typically develops due to minor head trauma leading to the rupture of bridging veins,
often exacerbated by conditions such as brain atrophy, anticoagulant use, or coagulopathies.[1] The condition primarily affects older adults, with an increasing incidence attributed
to aging populations and the widespread use of antithrombotic medications.[2] Clinical presentations of CSDH vary widely, ranging from subtle cognitive changes
and headache to more severe manifestations such as motor deficits and altered consciousness,
necessitating prompt recognition and treatment.[3]
The management of CSDH, while generally effective through surgical drainage techniques
such as burr hole evacuation, poses unique challenges due to the condition's recurrent
nature and the potential for significant complications.[4] Factors like advanced age, comorbidities, and anticoagulant therapy increase the
complexity of surgical intervention. Additionally, the variability in hematoma consistency
and the patient's intracranial pressure dynamics further complicate the procedure,
demanding a meticulous and cautious surgical approach.[5]
Complications associated with the surgical management of CSDH are significant, with
acute intracranial hemorrhage (ICH) being among the most severe. This includes intracerebral
hemorrhage (ICH) and brainstem hemorrhage, which can result from abrupt shifts in
intracranial pressure during rapid evacuation or decompression.[6] Such complications often arise due to the rupture of fragile cortical vessels or
sudden brain reexpansion, leading to catastrophic outcomes. These risks underscore
the need for optimized surgical strategies to prevent harm while effectively relieving
the hematoma.[7]
Rapid decompression, in particular, has been implicated as a key factor in triggering
ICH. The sudden release of intracranial pressure can create a vacuum effect, exacerbating
vessel vulnerability.[8] This has led to the exploration of alternative approaches, including gradual decompression
techniques, to mitigate these risks. Recognizing the importance of controlled intracranial
pressure modulation is critical in enhancing patient safety and improving surgical
outcomes.
To address these challenges, our study evaluates the effectiveness and safety of a
pressure neutralization technique involving gradual decompression using a wide-bore
cannula (16G or 18G) before dural opening. This approach aims to minimize the risk
of complications such as acute ICH by allowing for controlled evacuation, ultimately
enhancing postoperative recovery.
Materials and Methods
Study Design and Setting
This was a retrospective observational study conducted on patients diagnosed with
CSDH at Menoufia University Hospital, Shibin Elkom, Egypt, between January 2021 and
January 2024. Ethical approval was obtained from the institutional ethics committee
(8 -2024 NEUS 16–2) and informed consent was obtained from all participants before
enrollment.
Inclusion and Exclusion Criteria
Patients were included if they were diagnosed with CSDH and had a history of head
trauma based on clinical presentation and radiological evidence documented by computed
tomography (CT) of the brain and underwent surgical evacuation via one or two burr
hole craniotomy and if pressure neutralization technique was used intraoperatively.
Patients with severe coagulopathies interfering with surgery, classic opening of the
dura without the technique, or those lost to follow-up were excluded.
Preoperative Evaluation
All patients underwent detailed clinical and neurological assessments upon admission.
Presenting symptoms, including headache, hemiparesis, and convulsions, were documented.
Preoperative Glasgow Coma Scale (GCS) scores were recorded. Noncontrast CT of the
brain was performed to confirm the diagnosis and assess hematoma thickness, laterality,
and midline shift ([Fig. 1]).
Fig. 1 Preoperative computed tomography (CT) showing left frontoparietal chronic subdural
hematoma with midline shift.
Surgical Technique
After obtaining patient consent and completing preoperative preparation and anesthesia
consultation, the surgical intervention was conducted under sterile conditions and
general anesthesia. Depending on the size of the hematoma and the surgeon's discretion,
the procedure involved one or two burr hole craniotomies. The preparation began with
careful creation of burr holes, ensuring secure hemostasis of the skin and subcutaneous
tissue using bipolar cauterization, bone hemostasis with bone wax, and dural hemostasis
through cauterization. Before opening the dura, a wide-bore cannula (16G or 18G) was
inserted into the subdural space to a depth less than the hematoma's thickness, as
measured preoperatively on CT imaging. If two burr holes were utilized for hematoma
evacuation, cannulas were inserted simultaneously at both sites. The hematoma was
allowed to drain gradually through the cannulas prior to classic dural opening. This
approach facilitated gradual pressure neutralization. The amount of evacuated hematoma
and the time required for the technique were recorded. Following this, the dura was
opened conventionally to allow complete evacuation of the residual hematoma using
irrigation as per standard practice. The dura was left open, subgaleal drains were
typically placed, and meticulous hemostasis was achieved. The procedure concluded
with wound closure and smooth recovery from anesthesia ([Figs. 2] and [3]).
Fig. 2 Intraoperative picture showing prepared burr holes before pressure neutralization
technique start.
Fig. 3 Intraoperative picture showing cannula inserted and gradual evacuation through it.
Postoperative Management
Postoperative CT scans were performed within 24 hours to assess the extent of hematoma
evacuation, midline shift improvement, and residual hematoma ([Fig. 4]). Patients were monitored for neurological improvement and complications, including
infection, rebleeding, or seizures. Postoperative GCS scores were recorded before
discharge.
Fig. 4 Postoperative computed tomography (CT) after two burr craniotomy with use of pressure
neutralization technique showing complete evacuation of hematoma and no midline shift.
Data Collection and Analysis
Demographic data (age, sex), clinical features (presenting symptoms, GCS scores),
hematoma characteristics (thickness, side, and midline shift), operative details (burr
hole number, operative time, amount evacuated), and postoperative outcomes (clinical
improvement, hospital stay, residual hematoma, complications) were systematically
recorded.
Statistical Analysis
Data were analyzed using SPSS version 28.0 for Windows. Continuous variables, such
as age, hematoma thickness, operative time, and amount evacuated, were expressed as
mean ± standard deviation, median, and range. Categorical data, such as presenting
symptoms and postoperative complications, were presented as frequencies and percentages.
Results
Demographic and Clinical Characteristics
A total of 81 patients with CSDH were included in the study. The mean age of the patients
was 67 ± 8.767 years, with a median age of 68 years and a range of 45 to 78 years.
The majority of patients were male (56, 69.1%), and 25 patients (30.9%) were female.
Among the comorbidities, 24 patients (29.6%) had diabetes mellitus, while 57 patients
(70.4%) were nondiabetic. Hypertension was observed in 56 patients (69.1%), with the
remaining 25 patients (30.9%) being nonhypertensive. The preoperative GCS scores ranged
from 11 to 15, with a mean of 14 ± 1.314. [Table 1] demonstrates the demographic data of included cases.
Table 1
Demographic and clinical characteristics of patients
|
N
|
%
|
|
Age
|
|
|
• Mean ± SD
• Median
• Range
|
67 ± 8.7
68
45–78
|
|
Sex
|
Male
|
56
|
69.1
|
|
Female
|
25
|
30.9
|
|
DM
|
Yes
|
24
|
29.6
|
|
No
|
57
|
70.4
|
|
HTN
|
Yes
|
56
|
69.1
|
|
No
|
25
|
30.9
|
|
GCS
|
|
|
• Mean ± SD
• Median
• Range
|
14 ± 1.3
14
11–15
|
Abbreviations: DM, diabetes mellitus; GCS, Glasgow Coma Scale; HTN, hypertension;
SD, standard deviation.
Clinical Data Related to Subdural Hemorrhage
The predominant presenting symptom was hemiparesis (57 patients, 70.4%), followed
by headache (24 patients, 29.6%). Convulsions were observed in 13 patients (16.0%).
The subdural hematoma (SDH) was more commonly located on the left side (50 patients,
61.7%) compared with the right side (31 patients, 38.3%). The mean hematoma thickness
was 2.46 ± 0.5 cm, with a median of 2 cm and a range of 2 to 3 cm. Midline shift measurements
showed that 51 patients (63.0%) had a shift greater than 10 mm, 18 patients (22.2%)
had a shift between 5 and 10 mm, and 12 patients (14.8%) had a shift of less than
5 mm. Clinical Data is demonstrated in [Table 2].
Table 2
Clinical data related to subdural hemorrhage of the operated patients
|
N
|
%
|
|
Presenting symptoms
|
Headache
|
24
|
29.6
|
|
Hemiparesis
|
57
|
70.4
|
|
Convulsion
|
Yes
|
13
|
16.0
|
|
No
|
68
|
84.0
|
|
Hematoma side
|
Right
|
31
|
38.3
|
|
Left
|
50
|
61.7
|
|
Hematoma thickness (cm)
|
Mean ± SD
Median
Range
|
2.46 ± 0.5
2
2–3
|
|
Midline shift
|
Between 5 and 10 mL
|
18
|
22.2
|
|
Less than 5 mm
|
12
|
14.8
|
|
More than 10 mm
|
51
|
63.0
|
Abbreviation: SD, standard deviation.
Operative Data
Most patients (75, 92.6%) underwent a two-burr hole craniotomy, while a single burr
hole was used in 6 patients (7.4%). The mean technique duration was 6.64 ± 1.56 minutes,
with a median of 7 minutes and a range of 4 to 9 minutes. The mean amount of hematoma
during cannula evacuation was 61.17 ± 11.1 mL, with a median of 60 mL and a range
of 40 to 80 mL. Operative data are shown in [Table 3].
Table 3
Operative data of the patients
|
N
|
%
|
|
Burr hole number
|
One bur hole
|
6
|
7.4
|
|
Two bur holes
|
75
|
92.6
|
|
Technique time (min)
|
Mean ± SD
Median
Range
|
6.64 ± 1.5
7
4–9
|
|
Amount evacuated (mL)
|
Mean ± SD
Median
Range
|
61.17 ± 11.1
60
40–80
|
Abbreviation: SD, standard deviation.
Postoperative Assessment and Complications
The mean postoperative GCS score improved to 14.84 ± 0.37, with a median of 15. Clinical
improvement was reported as improved hemiparesis in 63 patients (77.8%) and resolution
of headache in 18 patients (22.2%). The average hospital stay was 4.2 ± 1.3 days,
with a median of 4 days and a range of 2 to 6 days. Postoperative imaging revealed
no midline shift in 62 patients (76.5%), while 19 patients (23.5%) showed a midline
shift of less than 5 mm. Residual hematoma was absent in 68 patients (84.0%) and was
mild in 13 patients (16.0%). Only one case underwent postoperative wound infection
(N = 1, 1.2%). Notably, no other postoperative complications, including rebleeding,
were observed in this cohort. [Table 4] delineates the postoperative assessment and complications.
Table 4
Postoperative assessment and complication of the operated patients
|
N
|
%
|
|
Post-GCS
|
14.84 ± 0.37
15
14 - 15
|
|
Clinical improvement
|
Headache improved
|
18
|
22.2
|
|
Improved weakness
|
63
|
77.8
|
|
Hospital stay (d)
|
4 0.2 ± 1.3
4
2–6
|
|
Midline shift improvement
|
No midline shift
|
62
|
76.5
|
|
Less than 5 mm
|
19
|
23.5
|
|
Residual
|
No
|
68
|
84.0
|
|
Mild
|
13
|
16.0
|
|
Postoperative wound infection
|
Yes
|
1
|
1.2
|
Abbreviation: GCS, Glasgow Coma Scale.
Discussion
SDH evacuation via burr hole craniectomy is a common procedure for patients with CSDHs.
Gradual decompression techniques, such as the use of wide-bore cannulas, are being
explored to minimize the risk of complications associated with rapid evacuation. Our
study aims to assess the effectiveness and safety of a pressure neutralization technique,
specifically gradual decompression using a wide-bore cannula (G16 or G18), prior to
dural opening, in the surgical management of CSDH.
In our study, we observed that the majority of patients showed improvement in neurological
status, with 77.8% experiencing weakness improvement and 22.2% showing improvement
in headaches. Postoperatively, most patients (76.5%) had no significant midline shift
and 84% had no residual hematoma. Our technique of gradual decompression resulted
in no postoperative complications, suggesting a favorable outcome for slow and controlled
evacuation. These findings are consistent with prior studies advocating for gradual
evacuation techniques to minimize risks like brainstem hemorrhage and ICH, in contrast
to rapid decompression approaches that may lead to neurological deterioration.
The technique employed had a mean operative time of 6.64 minutes, which is comparable
to other reports in the literature. Rusconi et al highlighted that careful and gentle
evacuation, avoiding excessive rotation of the head and maintaining a controlled drainage
technique, are key to minimizing complications.[9] This aligns with our practice of gradual decompression, which likely contributed
to relatively short operative times. Our technique, involving gradual decompression,
requires careful management but appears to reduce the need for prolonged surgical
intervention, aligning with findings that emphasize the importance of a controlled
approach.
The mean amount of hematoma evacuated collected through cannulas before surgical dural
opening was 61.17 mL, a value consistent with findings from other studies examining
CSDH surgery. In a study by Kim et al, the authors emphasized the importance of slow
drainage in preventing ICH, which is a potential complication when large volumes of
hematoma are evacuated too quickly.[10] Our approach, which avoids rapid drainage, may be partly responsible for minimizing
the risk of ICH, as we favor more gradual evacuation.
Postoperatively, patients showed a mean GCS of 14.84, indicating excellent neurological
recovery. This is consistent with findings from Sundstrøm et al, which suggested that
slow evacuation procedures could lead to better neurological outcomes.[11] The gradual decompression technique in our cohort seems to have contributed to preserving
cerebral perfusion and minimizing the risk of brain injury, resulting in favorable
GCS scores. In contrast, a study by Hsieh et al reported that rapid decompression
can lead to deterioration in GCS scores due to the risk of postoperative ICH and other
complications.[12]
In our study, we observed that 77.8% of patients experienced improvement in weakness,
while 22.2% had improvement in headaches. These findings indicate a positive clinical
response to gradual decompression, suggesting that a controlled and slow evacuation
technique can improve neurological recovery. This aligns with the findings in Rusconi
et al, which emphasized the benefits of gradual and controlled evacuation for improving
recovery outcomes and minimizing secondary complications.[9] In contrast, the study by Pavlov found that rapid decompression is associated with
a higher risk of neurological deterioration, which could negatively impact recovery,
particularly in terms of improvement in weakness.[13] This suggests that our approach of gradual decompression may reduce the risk of
such deterioration.
Our study also found that the mean hospital stay was 4.2 days, which is consistent
with reported literature. A study by Sundstrøm et al highlighted that larger hematomas
and significant midline shifts typically lead to longer hospital stays.[11] However, in our study, 76.5% of patients showed no midline shift postoperatively,
and 23.5% had a shift of less than 5 mm, indicating that gradual decompression may
better control midline shifts compared with more rapid techniques. These results align
with the study by Rusconi et al, which reported that slow drainage techniques were
associated with better midline shift outcomes.[9] Our findings suggest that gradual decompression can reduce the occurrence of significant
midline shifts and their associated complications.
The rate of residual hematoma in our cohort was low, with 84% of patients showing
no residual hematoma, and 16% presenting with mild residuals. This is consistent with
the recommendations in a study by Rusconi et al, which advised against excessive evacuation
as it may increase the risk of complications, such as brainstem hemorrhage.[9] In our study, 100% of patients had no postoperative complications, highlighting
the success of the gradual decompression technique. These outcomes contrast with the
findings in Kim et al and Hsieh et al, where rapid decompression was linked to a higher
risk of complications like ICH and brainstem hemorrhage.[10]
[12] Our approach, characterized by slow and controlled evacuation, appears to reduce
the likelihood of these complications, leading to a safer postoperative course.
One of the key strengths of our study is the use of a gradual decompression technique,
which has shown promising results in terms of clinical improvement, low complication
rates, and controlled midline shifts. Additionally, our cohort had a relatively short
hospital stay, reflecting the effectiveness of the gradual evacuation method. However,
a limitation of the study is its small sample size and single-center design, which
may limit the generalizability of the findings. Moreover, the study did not assess
long-term outcomes, such as recurrence of hematoma or neurological status over time,
which would provide more comprehensive insight into the benefits of gradual decompression.
Conclusion
Our study highlights the effectiveness of gradual decompression using wide-bore cannulas
in the management of CSDHs. This approach was associated with favorable clinical outcomes,
including significant improvement in neurological status, low complication rates,
and minimal midline shift. The absence of complications such as ICH or brainstem hemorrhage
supports the safety of gradual evacuation. Moreover, the technique is rapid and accessible
with very minimal cost.
