Keywords
cisternostomy - traumatic brain injury - decompressive craniectomy - hydrodynamics
Palavras-chave
cisternostomia - traumatismo cranioencefalico - craniectomia descompressiva - hidrodinâmica
Introduction
Traumatic brain injury (TBI) has a high incidence and mortality index in all age groups
and all around the world. It also has a huge economic impact, mainly in developing
countries, because of its direct and indirect costs and, therefore, public health
budget commitment.[1] A Brazilian retrospective study has shown an elevated cost associated with decompressive
craniectomy (DC) for TBI.[2] In the past decades, the incidence of trauma has significantly increased, and it
is predicted that in few years it will surpass the incidence of some chronic conditions,
such as vascular diseases.[3] The importance of this theme is clear; nevertheless, few advances have been made
in the last years, especially regarding neurosurgical approaches. In many countries,
trauma neurosurgery did not have significant advances[3] when it comes to trying to improve the outcomes and minimize the costs.
The knowledge of the mechanism of TBIs helps to understand the pathophysiology of
these lesions and how to improve the therapeutic approaches. Traumatic brain injuries
can be focal or diffuse. For focal lesions, there are detailed protocols describing
intensive care unit (ICU) management and surgery indication according to the type,
size, and topography of the injury. However, there are some controversies about the
treatment of diffuse injuries.[1] Considering surgical treatment, DC has been used in the past decades, although some
large trials have not shown real benefits in the outcomes,[4]
[5] and, besides, these patients required further surgeries to restore the normal brain
hydrodynamic.[6] Thus, DC is associated with elevated costs and few benefits.[2]
In this context, a well-defined technique, previously used in skull base and vascular
surgeries, has been proposed to improve cerebrospinal fluid (CSF) flow, brain hydrodynamic
and avoid DC.[1] Cisternostomy is a technique in which the basal cisternae are opened, thus helping
brain relaxation and, consequently, eliminating the need for DC. It is performed in
patients with moderate or severe TBI and diffuse injuries who would classically be
submitted to DC.
Methods
A research project was developed, evaluated and approved by the local human ethics
research committee. It was also registered at the Plataforma Brasil database. All study procedures were in accordance with the ethical standards of the
institutional and national research committee and with the 1964 Helsinki declaration
and its later amendments or comparable ethical standards.
This is a prospective study in which patients affected by TBI, considering the inclusion
and exclusion criteria, are submitted to cisternostomy as the main neurosurgical procedure.
The initial results are described in this paper, and an extensive review about diffuse
TBI, DC and cisternostomy is also performed. This protocol is still being applied
for a bigger evaluation.
The inclusion criteria are patients between 18 and 70 years without severe systemic
compromise and with diffuse TBI and classic indication for DC. A consent form was
signed by the legal responsible, and the procedure performed within a maximum of 6 hours
after emergency room (ER) admission. The pre and postoperative neurological exam and
computed tomography (CT) were evaluated.
An extensive literature review considering the terms cisternostomy, traumatic brain
injury, DC was conducted.
Results
After the local ethics committee approval, two patients were selected for cisternostomy,
and they are described below.
Case 1
A 20-year-old male patient fell off a height of 3 m and was associated to TBI. He
was admitted to the neurosurgical emergency department presenting with a Glasgow coma
scale (GCS) of 12 and isochoric pupils, incapable of providing further information
about his past medical history. He was evaluated according to Advanced Trauma Life
Support (ATLS) protocol, and no other lesions were found. On his admission brain CT,
a left acute subdural hematoma (ASH) with important midline shift was observed ([Fig. 1]). The Zunkeller index was greater than 5 mm. In this context, a microsurgical cisternostomy
([Fig. 2]) was proposed and performed within the first 6 hours after admission. The hematoma
was drained during surgery; however, despite this, the brain remained swollen. Because
of this, microsurgical technique for opening the basal cisternae and the lamina terminalis
was performed. After this, a proper brain relaxation and edema decrease could be observed.
Therefore, there was no need for a DC. The patient had a good recovery and was alert
on the first postoperative day, with GCS of 15 and an adequate postoperative brain
CT ([Fig. 1]), without midline shift. He was discharged a few days after with a Glasgow outcome
scale (GOS) of 5.
Fig. 1 (A) Admission axial brain computed tomography revealing a left subdural hematoma and
brain swelling with midline shift; (B) 24-hour postoperative computed tomography revealing swelling reduction and no midline
deviation.
Fig. 2 Opticocarotid microsurgical cisterna opening – Case 1.
Case 2
A 69-year-old female patient presented to the neurosurgical emergency department after
a fall from her own height and sudden unconsciousness. She arrived to the hospital
with anisocoric (left > right) pupils, with a GCS of 3 and under mechanical ventilation.
She did not have other systemic lesions after evaluation by the ATLS protocol. On
her past medical history, it could be noticed that she was previously submitted to
a ruptured aneurysm clipping surgery at the same hospital and required a ventriculoperitoneal
shunt. After this, she remained with neurological sequelae, especially concerning
her cognitive status. She also used drugs for blood hypertension and acetylsalicylic
acid due to a previous stroke.
On her admission brain CT, a massive ASH with midline shift ([Fig. 3]) and a Zunkeller index greater than 5 mm were observed. She underwent a cisternostomy
within less than 6 hours after admission ([Fig. 4]). The hematoma was drained during surgery; however, despite this, the brain remained
with noticeable swelling and transcalvarial herniation. Therefore, a microsurgical
cisternostomy was proposed through the opening of the basal cisternae and the lamina
terminalis. After this it could be noticed a proper brain relaxation, edema decrease
and herniation resolution. There was no need for skull removal through DC. She had
a slower recovery when compared with the pilot case; however, her postoperative brain
CT showed a good surgical result ([Fig. 3]) and she was discharged a month after the initial procedure with a GOS of 4 and
with no need for further surgery.
Fig. 3 (A) Preoperative brain computed tomography disclosing huge left subdural hematoma and
brain swelling with severe midline shift; (B) 24 hours postoperative brain computed tomography revealing brain swelling and midline
deviation reduction.
Fig. 4 During microsurgical cisternostomy it could be noticed the presence of an aneurysm
clipping (internal carotid artery posterior communicating segment) – Case 2.
No other neurosurgical procedures were required for either patient, and they had satisfactory
recovery, evaluated through GOS and postoperative CT.
Discussion
Traumatic brain injury is a major cause of morbidity and mortality, especially in
developing countries.[2] Direct traumas generally cause focal lesions, such as epidural hematomas, brain
contusions, and skull fractures.[1] The neurosurgery procedures for draining these hematomas, if they have significant
repercussion, are well established in the literature. The Brain Trauma Foundation
Guidelines describe these indications.[1]
[7] On the other hand, due to inertial forces, in some cases, there are diffuse injuries,
mainly brain swelling, traumatic SAH, diffuse axonal injury (DAI), and subdural hematomas.[8] These lesions constitute a therapeutic challenging and require a multidisciplinary
team for a proper management.
For diffuse TBI, DC may be an option for decreasing the raised intracranial pressure
associated when there is an important brain swelling and midline shift causing brain
herniation. However, many huge trials, such as DECRA and RESCUE-ICP, have demonstrated
that this procedure has high morbidity and mortality rates.[1]
[2]
[9] The technique and indications of DC have been extensively described in previous
studies;[4]
[10] nevertheless, the outcomes and costs are high, and these patients always require
at least one more neurosurgical procedure for cranioplasty.
Recently, a Brazilian study had shown elevated costs associated with DC for TBI.[4] Patients who do survive generate greater hospitalization costs, and the majority
of them will require future hospitalizations for treatment of clinical complications
and other procedures, such as ventricular shunts and cranioplasty. Some studies have
demonstrated that the real cost of these patients is ∼ 10 to 15 times greater than
the cost of the treatment in the acute phase.[4]
[11]
[12]
Encephalic hemodynamic is severely altered after skullcap removal, and many complications
are associated with this, such as hydrocephalus. In some cases, after DC, a permanent
shunt is required in addition to further cranioplasty (with autologous or heterologous
bone) to restore hydrodynamics.[13] Cranioplasty is a surgical procedure that requires another hospitalization after
the acute phase and offers some risks, such as infection. Besides, it could be expensive,
especially if synthetic prosthesis is used. A national population analysis performed
in the United States revealed a mean total cost of U$ 94,356, with hospital payments
comprising most of this cost at a mean of U$ 82,680.[14]
Recent evidence suggests that in trauma, edema formation is also associated with CSF
entrance into the brain parenchyma via the low-resistance para-arterial space or decreased
interstitial fluid efflux or a combination of the two processes.[6] There is a hypothesis that the glymphatic removal of excess interstitial fluid decreases
new injury, and, therefore, CSF is shifted from the cerebral cisterns to the brain
after TBI.[6] The hydrodynamics of the brain is altered after a severe TBI associated with diffuse
lesions due to this mechanism.
Because of these principles, anatomy and physiology of the cisternae were studied[4] in the context of trauma. Commonly, the basal cisternae opening is a procedure performed
in skull base and vascular neurosurgeries. It is useful for brain relaxation, helping
to improve CSF flow and brain hydrodynamics.[6]
[15] In diffuse TBI, the cisterns are usually compressed, and the CSF flow is altered.[1]
[3]
[16] The Marshall Graduation System considers the cisternae status for TBI graduation
and mortality estimate. Opening cisterns in a tight brain is a difficult procedure.
Nevertheless, after the opening of the interoptic, opticocarotid, and lateral carotid
cisternae, the brain become lax. This procedure reverses the cisternal pressure gradient,
causing CSF to flow back into the cisterns, thus decreasing the intracranial pressure.[6]
[15]
Cherian et al[1]
[3] described a case series of cisternostomy for the treatment of TBI, comparing it
with DC, and achieved good results. Cisternostomy presented decreased morbidity and
mortality when compared with DC. Cisternostomy has a low cost, same surgical duration
and better outcomes. Patients will not require additional procedures, as they do after
DC: a cranioplasty is always performed, and, in many cases, patients required ventriculoperitoneal
shunt to restore brain hydrodynamics. In this protocol, the lamina terminalis is also
opened.
After local ethics committee approval and national databank registration, this technique
is being performed at our institution for patients with diffuse TBI to whom DC would
be classically indicated (considering established protocols for this surgery). Inclusion
and exclusion criteria were applied to perform this study, considering age, time from
the trauma until the surgery, the presence of severe major internal organ lesions,
and family authorization.
These are the initial results of an extensive protocol that is being applied at our
institution.
Conclusions
Cisternostomy was performed in the cases described in the present manuscript as part
of this new protocol for the treatment of TBI. A similar study was previously published
only by a single center with good outcomes. Patients evolved with a proper functional
recovery and did not require further neurosurgical interventions. This technique is
an advance in neurotrauma surgery. Low costs, morbidity and mortality are the major
benefits of cisternostomy. A case series is being developed at our institution for
a better analysis of the results.
