Keywords
cranioplasty - external ventricular drain - post-traumatic hydrocephalus - neurosurgery
Palavras-chave
cranioplastia - dreno ventricular externo - hidrocefalia pós-traumática - neurocirurgia
Introduction
The increase in intracranial pressure (ICP) is a neurological complication resulting
from numerous pathologies that affect the brain and its compartments, including intracranial
factors, like expansive mass lesions – such as tumors and hematomas –, or extracranial
events – such as hyponatremia, hypotension, and hypoxia.[1]
Decompressive craniectomy (DC) is a surgical procedure adopted in emergencies as an
alternative to reduce ICP, especially in cases refractory to clinical therapies, in
order to improve patient survival.[2] However, DC is associated with several complications, which can develop quickly
– such as hemorrhages, extracranial brain herniations, cerebrospinal fluid fistulas,
postoperative infections, convulsions – or later, such as subdural hygromas, motor
trephine syndrome, and hydrocephalus (HC).[2]
Regarding HC after DC, it can be said that this is a common complication, with an
incidence of 0.7 to 86% of cases, depending on the diagnostic criteria,[3]
[4] so that ∼ 8 to 11% of the patients need a measure of therapeutic intervention.[4]
One of the ways to manage the HC developed after DC is to perform the implantation
of a ventriculoperitoneal shunt (VPS) followed by the definitive cranioplasty (CP).
This conduct can be carried out simultaneously or in two programmed stages, with experiences
varying according to each center.[5]
Thus, the present study aims to add to the literature on the topic of the descriptive
presentation of the results of an unusual surgical method: the implantation of an
external ventricular drain (EVD) for the management of consecutive HC of decompressive
hemicraniectomy in the transoperative of CP, which evolved with a positive prognosis
in a series of five patients.
Methods
This is an observational, cross-sectional and descriptive study of patients seen at
the Neurosurgery Department of the Hospital da Restauração, Recife, PE, Brazil, from
February 2016 to October 2019.
Patients of both genders who presented HC and externalization of the brain through
the cranial vault after decompressive hemicraniectomy and underwent EVD implantation,
to allow the CP procedure, in the same surgical procedure, were included. Patients
who did not meet the inclusion criteria were excluded.
All patients and relatives involved filled out a consent form, authorizing participation
in the present study, as well as disclosure to the scientific community.
The cases were evaluated regarding sex, age, etiology, initial complication, time
elapsed between the DC and the CP, and the volume of cerebrospinal fluid (CSF) drained
in the EVD. This information is summarized in [Table 1].
Table 1
Clinical profile, etiology, initial complication, time elapsed between decompressive
craniectomy and cranioplasty and volume of cerebrospinal fluid drained in the external
ventricular drain of the reported patients
|
Patient
|
Gender
|
Age (yyearold)
|
Etiology
|
Initial complication
|
Volume of CSF drained in the EVD
|
Time elapsed between DC and CP
|
|
1
|
M
|
24
|
Motorcycle accident
|
ASDH
|
650 mL
|
18 months
|
|
2
|
M
|
27
|
FAP
|
ASDH
|
200 mL
|
38 months
|
|
3
|
M
|
33
|
FFS
|
ASDH
|
150 mL
|
30 months
|
|
4
|
M
|
40
|
IS
|
CE
|
150 mL
|
54 months
|
|
5
|
F
|
48
|
IS
|
CE
|
150 mL
|
17 months
|
Abbreviations: ASDH, acute subdural hematoma; CE, cytotoxic edema; CP, cranioplasty;
CSF, cerebrospinal fluid; DC, decompressive craniectomy; EVD, external ventricular
drain; F, female; FAP, firearm projectile; FFS, fall from stairs; IS, ischemic stroke;
M, male.
The reconstruction of the skullcap was guided by a customized three-dimensional (3D)
technique, using polymethylmethacrylate (PMMA).[6]
[7]
[8]
[9] After CP, the EVD was closed and removed in an interval of 24 to 48 hours, with
the patient still in the intensive care unit (ICU).
An integrative literature review on the topic was developed, seeking to relate the
scientific discussion to the findings of the present study. The research was conducted
in the PubMed platform, using the descriptors decompressive craniectomy AND hydrocephalus, and cranioplasty AND external ventricular drain.
Results
A total of 5 patients, 4 (80.0%) males and 1 (20.0%) female, whose ages ranged from
24 to 48 years old, with a median of 33 years old, underwent DC due to refractory
increase of the PIC. The etiologies of this entity were automobile accidents, firearm
projectiles, falls from stairs, and ischemic strokes.
As an initial complication, the victims of traumatic brain injury developed acute
subdural hematoma, and the cases of stroke involved cytotoxic edema, both with increased
ICP refractory to clinical therapies. After undergoing DC, all patients developed
HC in the postoperative period.
For the management of post-DC HC, an EVD was implanted in the same surgical procedure
that the CP was performed. Between 150 and 650 ml of cerebrospinal fluid (CSF) was
drained, according to the need for correction of cerebral herniation in each patient,
before undergoing cranioplasty. The time elapsed between the DC and the CP ranged
from 17 to 54 months, with an average of 31.4 months, with no uniformity in this interval.
All patients evolved well, without neurological deficits in the immediate postoperative
period, and were referred to routine outpatient follow-up ([Figs. 1]
[2]
[3]
[4]
[5]).
Fig. 1 Patient 1. Comparatively, the visual and tomographic aspects of the pre- (A, B) and
postoperative (C, D) of the EVD.
Fig. 2 Patient 2. Comparatively, the visual and tomographic aspects of the pre- (A, B) and
postoperative (C, D) of the EVD.
Fig. 3 Patient 3. Comparison of the pre- (A) and postoperative (B) visual aspect of the
EVD followed by CP, in view of the HC developed after decompressive craniotomy.
Fig. 4 Patient 4. Comparison of the pre- (A) and postoperative (B) visual aspect of the
EVD followed by CP, in view of the HC developed after decompressive craniotomy.
Fig. 5 Patient 5. Comparatively, the visual and tomographic aspects of the pre- (A, B) and
postoperative (C, D) of the EVD.
Discussion
In the emergency environment, DC has consolidated itself as an effective measure to
decrease the ICP, which rises due to several scenarios, such as infections, tumors,
hemorrhages, strokes, and traumatic brain injuries.[1]
[2]
[10]
[11]
[12] In this procedure, the opening of the cranial vault and of the dura mater allows
the distribution of the brain component, relieving the ICP and favoring patient survival.[2]
[10]
[11]
[12]
However, like any other surgical procedure, DC is not free of possible complications.
In this regard, progressive neurological decline can be mentioned,[10]
[13] in addition to hemorrhages, infections, inflammations and, also, disorders of the
ventricular system,[14] where the CSF flows. Among the latter complications, there is HC, which, according
to the literature, is triggered by changes in pulse wave pressure through the convexity
of the brain[15]
[16] and by a reduction in venous flow in the medial margin of the craniectomy.[16]
[17]
[18] Some studies also point to the extension of the craniectomy as a predisposing factor
for HC.[4]
[16]
[18]
[19]
The HC developed after DC has a very variable incidence rate, according to scientific
studies, in view of the difference in the criteria adopted by the centers for diagnosing
this condition.[3]
[4] Some authors consider necessarily the clinical manifestations of HC, while others
only analyze the expanded ventricular morphology by computed tomography (CT), converging
on the concept of ventriculomegaly.[16]
[17]
[20]
In view of the post-DC HC, ∼ 1 in 10 cases requires intervention.[4]
[14] In this scenario, CP is discussed as an alternative for a better prognosis for patients,
considering the therapeutic potential[21]
[22]
[23] and neurological recovery,[21]
[22] as well as the aesthetic advantage.[23] However, some authors claim that there are still no strong scientific correlations
between cranioplasty and better neurological results.[23]
Regarding CP, moreover, it is known that there is a predisposition to other complications,
especially after DC.[12]
[14]
[21]
[23] Among these complications, in addition to those associated with the postoperative
period of DC, the possible impasses linked to the consolidation of the bone flap are
added.[14] In this sense, the scientific community debates strategies to mitigate these obstacles,
analyzing issues such as the clinical conditions of the patients and their comorbidities,
the method of preservation of the bone flap, the material used for cranial reconstruction,
the moment when CP should be indicated, and the surgical technique addressed.[10]
[21]
[23]
Regarding the profile of the patients (age, sex, presence of comorbidities, clinical
history), preservation of the bone flap, and the material used for CP, the studies
did not find associations with greater risk of complications.[10]
[21]
[23] However, the use of autologous bone – which is more common, especially in centers
with less resources – seems to be related to higher probabilities of bone flap resorption
and implant failure when compared with heterologous materials.[23]
For the procedures of the present study, in fact, the diversity of patient profiles
did not imply different predispositions to possible risks. As for the material adopted
in the plastic surgery, the customized PMMA prosthesis was chosen, by 3D printing
– due to the accessibility and reproducibility of the technique, in addition to the
therapeutic and aesthetic results –, according to the experience with these operations
of our center.[6]
[7]
[8]
[9]
There is also no consensus on the appropriate time for CP intervention. On the one
hand, there are a number of studies that associate late reconstruction with unfavorable
results.[2]
[12]
[20]
[23] In view of this, there are authors who suggest using a period of ∼ 2 weeks after
DC as a reference, when, generally, cerebral edema can already be seen exteriorizing
the cranial vault by CT, which is compatible with the clinical examination of the
patient during this period.[20]
[23] Other researchers also point to a period of up to 12 weeks after craniectomy, in
order to avoid the need for new interventions.[2] On the other hand, there are several other evidence that contradict this aspect.
Within this controversy, the systematic review developed by De Cola et al. indicated
that an interval of 3 to 6 months between DC and CP is favorable to better motor and
cognitive recoveries.[24]
Regarding the surgical technique, CP, by itself, is already presented as a therapeutic
approach, and is even considered sufficient, in the circumstances in which the brain
is flaccid.[25]
[26]
[27] There are even reports in the literature of patients in whom the mechanism of deviation
of CSF proved to be unnecessary.[22] However, in conditions of tension and brain herniation, CSF drainage may be required,[16] correcting the exteriorization of the brain and enabling the reconstruction of the
skull. About these situations, there is a wide discussion in scientific studies as
to the most effective and safe ventricular drainage conduct.
Regarding the VPS derivation strategy, commonly performed in various centers, there
are several articles that associated CP in the same operative act as this procedure
as a factor for obtaining complications – such as infection and bone resorption –,
suggesting intervention in stages as most appropriate.[5]
[28]
[29]
[30] Despite this, a study showed positive evaluations of a “single-stage surgical technique
with temporary occlusion of the distal shunt catheter”, associated with a slow reduction
in the pressure of the programmable VPS valve.[31]
The effectiveness of using the programmable VPS technology in the management of CP
after DC is reiterated by other authors,[25]
[31]
[32]
[33] especially when compared with the permanent VPS, which may even involve excessive
drainage and subdural collections.[16]
[34] However, this is an expensive approach and, therefore, inaccessible to the socioeconomic
conditions of most patients.[16] Still, as an alternative for performing simultaneous CP to the management of post-DC
HC, a study obtained better results from simultaneous ventriculostomy to CP, followed,
in a few days, by the implantation of VPS.[25]
On the other hand, considering the impasses related to the use of permanent shunt,
for patients who need CSF drainage in the act of CP, the temporary lumbar or ventricular
drainage presented themselves as valid and effective strategies.[16]
[22] Performing an aspiration procedure at the CP, the study by Kutty et al. could avoid
the use of VPS in 10 of 11 patients with ventriculomegaly due to DC, with therapeutic
success.[16] Following this trend, the execution of EVD in the intraoperative period of CP, through
the HC developed after DC, draining CSF according to the need to correct cerebral
herniation, proved to be a viable alternative.
Conclusion
The scientific community still deals with countless uncertainties about the conduct
of intervention to HC resulting from DC. Despite this, studies have already found
the effectiveness of CP, either alone or associated with a method of draining CSF,
when necessary. There is a requirement for drainage by thorough technique, such as
programmable VPS, in the search to avoid further complications. However, this procedure
requires resources that are inaccessible to most patients.
Studies on the use of permanent VPS reveal other risks linked to this conduct, such
as excessive drainage and subdural collections. Furthermore, the indication of the
procedure, in stages, using VPS, requires the performance of more than one surgical
act and, therefore, a constant monitoring of the clinical evolution of the patient
to mitigate the impasses of these interventions.
Hence, other CP strategies simultaneous to the management of post-DC HC, not necessarily
related to VPS, should be considered and evaluated more deeply, in view of the verification
of the effectiveness in procedures of this scope, such as the EVD addressed in this
study.
