Keywords
endoscopy - cavernoma - intraventricular
Cavernomas (CVs) are common cerebral lesions, most frequently located in the supratentorial
(74–90%) rather than the infratentorial (10–26%) region.[1]
[2] They can be single as well as multiple lesions and can present themselves sporadically
or can be an expression of a genetic disease: three genes have been identified for
the inherited form.[3]
[4] The intraventricular location is rare and accounts for approximately 2.5% of all
CVs of the central nervous system,[5] with the atrium being the most common site.[6] A CV arising from the septum pellucidum is a rare entity, and only four cases have
been reported in the international literature.[7]
[8]
[9]
[10] Generally speaking, CVs may be detected incidentally or present with seizures, headaches,
or focal neurologic deficits due to hemorrhage. The clinical features largely depend
on the location of the CV. In the supratentorial compartment, seizures are the most
common symptoms in 39 to 79% of the patients.[11] The intraventricular location may, most commonly, present either with hemorrhage
(14–22%), seizures (14%), or hydrocephalus, or may even be asymptomatic.[4]
[10]
[12] CVs of the septum pellucidum do not have any specific clinical features. The standard
treatment for CVs is surgical removal, although, most recently, even stereotactic
radiotherapy has been used.[3] The transcranial transcortical or the transcranial interhemispheric approaches are
the surgical classical routes used for CVs located within the septum pellucidum. A
minimally invasive surgical technique, such as the endoscopic one, can be used to
decrease the surgical brain manipulation as well.
Case Report
History
The patient's clinical history started when she was 13 years old and presented with
a generalized tonic–clonic seizure, which lead to a magnetic resonance imaging (MRI)
of the brain with the subsequent diagnosis of multiple intracerebral CVs: a left frontal
intraparenchymal one (35 mm in diameter) and a left posterior temporal one, both within
the parenchyma (23 mm in diameter), and an intraventricular one (30 mm in diameter).
Despite the best medical treatment, the epilepsy was not well controlled and the patient
had up to three to four epileptic attacks per week. This case was discussed several
times at our multidisciplinary meeting, as well as with the patients and the parents.
The final decision was to remove the largest and the apparently symptomatic CV, and
this decision was guided by a video-EEG (electroencephalogram). The left frontal CV
was removed at the age of 14 years, with epilepsy symptoms being temporarily improved.
Unfortunately, after 10 months, she started to complain of epilepsy again, with a
clinical absence type behavior, pointed for temporal lobe origin type of seizures.
Thus, a few months later, the left posterior temporal lesion was removed as well.
The second operation gave very good medical results in terms of seizures control.
The episodes dropped to one or two focal seizures per year. The third lesion, the
intraventricular one, was followed up with a yearly MRI scan. At the age of 21, because
the lesion had increased in size (∼8 mm) and because of the patient's desire, we decide
to remove it using a transcranial interhemispheric approach. The operation was uncomplicated,
and the patient was discharged home a week after the procedure. At that stage, no
other lesions were present, and in the following 10 years, the follow-up MRI scans
did not show any recurrence or new CVs. When she was 32 years old, on the yearly follow-up
scan, a newly developed lesion was identified. This lesion, suspicious for CV, was
small (6 mm) and located within the septum pellucidum. Because of its small size,
the location, and the absence of symptoms, a conservative treatment option was followed.
Unfortunately, the lesion doubled in size in the following 18 months and therefore
the patient was very adamant about having it removed ([Fig. 1]). We were a bit reluctant because the patient was completely asymptomatic and had
not had any epileptic attack for 10 years. Upon neurologic examination, she presented
no issues. Finally, we took the decision to remove the lesion and we started to discuss
how to approach it. We were wondering whether to use the same interhemispheric approach
with the possibility of encountering scar tissue or if it was better to use a new
surgical route such as a transcortical one. Finally, we decided to use something completely
different and we opted for a transcortical endoscopic approach.
Operation
With the patient in the supine position through a single burr hole, placed slightly
more laterally in relation to Kocher point, a purely endoscopic approach was performed
and the lesion was completely removed ([Video 1]). A rigid endoscope was used and guided by the neuronavigation. Upon inspection,
the lesion ([Fig. 2]) presented with two veins attached to it (one rostral and the other caudal). The
removal began with the coagulation and dissection of the septum pellucidum superior
to the CV location. After accurate coagulation and section of the caudal vein, using
endoscopic forceps allowed the creation of a “pedunculated” CV. The insertion of an
endoscopic rongeur in the space between the peel-away cannula and the endoscope allowed
keeping the CV in place, avoiding its fluctuation in the ventricles. This maneuver
allowed the exposition and easy dissection of the rostral vein, which, eventually,
was coagulated and cut. The CV was then freed from the surrounding tissue and finally
removed. An external ventricular drainage was precautionary left in the right ventricle
just for 24 hours.
Fig. 1 (A) Axial and (B) coronal T1-weighted preoperative magnetic resonance (MR) images reveal an 18-mm
multilobulated mass with heterogeneous signal intensity located at the septum pellucidum.
Postoperative (C) axial and (D) coronal T1-weighted image shows no cavernoma remnant.
Fig. 2 Intraoperative photograph showing a neuroendoscopic view of a cavernoma.
Video 1
Surgical video of a purely endoscopic resection of a cavernoma.
Pathological Findings
The histological examination revealed multiple dilated and congested vascular spaces
lined by the endothelium, confirming the diagnosis of a CV.
Postoperative Course
The postoperative course was uneventful, and the patient was discharged home 2 days
later. Serial follow-up MRI scans did not show any new or recurrent lesion at 5 years
follow-up.
Discussion
The management of intracerebral CVs may be complex and is related to the specific
location and symptoms. From a general point of view, surgery is indicated in patients
with intractable seizures, recurrence of hemorrhages, focal deficits, the presence
of mass effect, and lesions increasing in size. Patients with asymptomatic lesions
located in eloquent areas may be observed.[10] Intraventricular lesions may present a technical problem further on. The standard
approaches used for lesions in this location (lateral and III ventricles) are the
transcranial transcortical approach, which is technically easier but requires large
ventricles and a corticotomy to enter the brain, which may lead to epilepsy. The other
approach used is the transcranial interhemispheric transcallosal route. This approach
is more anatomical and does not require large size ventricles, but it is technically
more demanding. In addition, if the callosotomy is too posterior or too extensive,
it can give way to a disconnection syndrome problem. An alternative way, a less invasive
approach, may be the use of an endoscope as a helping tool to the microscope or purely
endoscopic approach. The endoscopy technique is being increasingly used for the treatment
of intraventricular tumors, but its use in the excision of an intraventricular CV
still generates fear and reluctance among neurosurgeons due to the vascular nature
of these lesions and the possible difficulty in achieving a good hemostasis.[13]
[14]
[15] Microsurgical excision is thus considered the standard treatment and a safer technique
compared with neuroendoscopy.[14]
[16] To the best of our knowledge, this is the first case of a septum pellucidum CV resected
purely endoscopically. In this case, the presence of three previous different craniotomies
(among these also a transcallosal approach) made the endoscopic resection technique
to go through a new surgical corridor, avoiding the presence of the inevitable scar
tissue and keeping the surgical act to a minimum. Our choice was also helped by the
small size of the CV. However, we were prepared to convert our approach into an open
procedure in case of technical problems or bleeding that could obscure our vision.
From this case, instead, we have learned that the use of the endoscope may allow for
a better visualization all around the lesion if compared with the microscope. As for
many clinical situations, the most important criterion is patient selection as well
as the surgeon's experience. The use of minimally invasive surgery permits a better
surgical outcome in terms of prompt recovery and reduced morbidity.
We believe that this approach should be kept in mind, especially for small lesions
located in deep anatomical regions, which would require, otherwise, a more demanding
microsurgical open exposure.
