Foramen magnum meningioma’s management: the experience of the department of neurosurgery in Marrakesh
Farouk Hajhouji1,&, Mohammed Lmejjati1, Khalid Aniba1, Mehdi Laghmari1, Houssine Ghannane1, Said Ait Benali1
1Department of Neurosurgery, Mohammed the sixth University Hospital, Marrakesh, Morocco
Farouk Hajhouji, Department of Neurosurgery, Mohammed the sixth University Hospital, Marrakesh, Morocco
Our study is a retrospective analysis of the clinical data, surgical outcomes,
histological finding and prognosis of foramen magnum meningiomas through
a serie of 8 cases operated at the department of neurosurgery at Mohammed
VI medical university hospital, Marrakesh. From January 2002 to December
2015. There were 3 male and 5 female patients (mean age, 46.75 years).
Cervico-occipital pain (100%) and motor deficit (100%) were the most common
MRI was the most appropriate diagnostic tool in visualizing tumors of
region. All operations were performed by the posterior approach and gross
total resection was achieved in 7 cases. Surgical mortality was 20%. 3
other patients had complications like CSF leak (25%), meningitis (12,5%)
worsening of neurological deficit (12.5%) but made neurological recovery
Foramen magnum meningiomas have long been regarded as difficult lesions both
in terms of diagnosis and management. However, with the availability of
MR imaging, newer surgical techniques and skull base exposures, the excision
of these lesions is becoming easier and safer.
Foramen magnum meningiomas (FMM) account for 0.3% to 3.2%
of all meningiomas, between 4.2% and 20% of all posterior fossa
meningiomas and 8.6% of all spinal meningiomas .
FMM have been defined by george as tumors arising anteriorly from the inferior
third of the clivus to the superior edge of the C2 body,
laterally from the jugular tubercle to the C2 laminae,
and posteriorly from the anterior border of the occipital squama
to the spinal process of C2 .
FMM is one of the most challenging types of meningioma to treat because a large
number of vital neurovascular structures, which are sensitive to
injury, are crowded together in this deeply hidden central area.
The intent of
this paper is to provide an overview of the clinical data, surgical
outcomes, histological finding and prognosis of FMM through a serie
of 8 cases operated
at the department of neurosurgery at Mohammed VI medical university
Between january 2002 and decembre 2015 eight patients were operated for FMM at the department of neurosurgery at mohammed VI medical university hospital, marrakesh, Morocco.
Medical charts and records were reviewed retrospectively to determine demograophic data, clinical findings, morphological assessment, surgical approaches and outcomes.
Between January 2002 and December 2015, eight patients were diagnosed
with foramen magnum meningiomas. 3(37.5%) were male and 5 (62.5%)
were female. The median age was 46.75 (ranging from 23 to 60) The mean duration
was 13 months (ranging from 4 to 36 months). Presenting signs and
symptoms were headache and neck pain in all patients (100%), difficulty
in 2 patients (25%), gait ataxia in 2 patient (25%) brachalgia
and arm paresthesias in 2 patients (25%), monoparesis in one patient (12.5%),
2 patients (25%) and quadriparesis in 5 patients (62.5%). The mean
preoperative KPS was 72.5% (ranging from 60% to 80%). 5/8 (62.5%) of the
located anterolateral (Figure
1), 3/8 were anterior. The mean maximum diameter of the tumors on
MRI was 2.75 cm. VA encasement was obeserved in one patient (Figure
Posterior midline approach was performed in all cases (Figure
3). Gross-total resection (GTR) was achieved in 7 of these lesions (87.5%)
4) and subtotal resection was achieved in one patient who had VA encasement.
surgical mortality was observed in two patients (25%) who had postoperative
pneuomnia due to swallowing difficulties . CSF fistula occurred in 2 (25%), One
patient of them developed meningitis (12.5%) and was successefully treated with
Transient worsening of neurological deficit was seen in one patient (12.5%) which
spontaneously recovered after two months.
All cases were WHO grade I meningiomas. 75% of the tumors were meningothelial,
12.5 % was transitional and 12.5% was psammomatous. Patients were followed for
a median of 20 months (range: 3-48 months ). At the latest follow up,6 patients
were alive and functionally independent. Mean Karnofsky score was 85% at the
latest follow up. No recurrences were observed.
The foramen magnum contains several critical neuroanatomical and
vascular structures of which the surgeon must be aware. The neural
structures include the cerebellar tonsils, inferior vermis, fourth
aspect of the medulla, lower cranial nerves (9th-12th),
rostral aspect of the spinal cord, and upper cervical nerves (C1
and C2). arterial structures include the VAs, PICAs, anterior and
arteries, and the meningeal branches of the vertebral, external,
and internal carotid arteries .
Meningiomas occur three times more often than neurinomas, which are the next
most common type of benign tumors among those that occur at the
foramen magnum. In addition to neurinomas, the differential diagnosis
of a foramen
magnum meningioma can include dermoids, epidermoids, teratomas,
lipomas, hemangioblastomas, cavernous angiomas, giant thrombosed
aneurysms of the
vertebral artery, intramedullary cervical spinal cord tumors, and
syringomyelia . The clinical presentation of patients
with FM lesions varies greatly and can mimic many other neurological
multiple sclerosis, cervical spondylosis, and amyotrophic lateral
sclerosis. The clinical course is slowly progressive, leading to
motor weakness, gait ataxia, and a relatively less common lower
cranial nerve palsies [4,5].
MRI is the modality of choice for defining FMM, It clearly delineates the exact
tumor size, location, site of dural attachment, and relation to
vascular and neural structures; MRI also provides an opportunity
to assess the consistency
and vascularity of the tumor .
The foramen magnum can be approached via anterior, lateral, and posterior approaches.
The anterior transoral approach is rarely conducted to reach intradural
lesions such as meningiomas because of problems with dural repair,
risk of CSF leakage, and meningitis . Tumors situated
posterior or posterolateral to the spinal cord or the brainstem
can be safely resected via a posterior midline suboccipital approach
combined with C-1
laminectomy . It’s a classic approach wich is familiar
to most neurosurgeons  and carries a lower morbidity
rate than skull base approaches . Tumors situated
anteriorly may be accessed with the far-lateral approach described
by Heros  for VA aneurysms, or the extreme lateral
modification described by George et al. . The most
devastating complications related to this approach are lower cranial
nerve palsies and
vertebral artery injury . In our case as few other
only the posterior midline approach was used. According to BYDON
GTR can be achieved in 61-100% of the cases. Also vertebral
artery involvement significantly affected the rate of radical resection
According to our experience, we think that, the conventional suboccipital midline approach with C1 laminectomy is sufficient to perform safely the adequate microsurgical removal of foramen magnum meningiomas.
What is known about this topic
- Meningiomas located in the Foramen magnum are quite uncommon;
- Their surgical treatments remain a technical challenge;
- The far lateral approach is widely considered the gold standard approach by many skull base surgeons.
What this study adds
- The conventional suboccipital midline approach can safely achieve a total resection of foramen magnum meningiomas;
- A good knowledge of the regional surgical anatomy is sinequanone to achieve a total resection and avoid iatrogenic lesions of the VA and low cranial nerves.
Authors declare no competing interests.
All the authors have contributed to the writing of this manuscript. All the authors have read and approved the final version of this manuscript.
Figure 1: axial T1 weighted MR image shows an anterolateral foramen magnum meningioma
Figure 2: axial T1 weighted MR image shows the VA encasement by a foramen magnum meningioma
Figure 3: peroperative photograph shows the microsurgical removal of foramen magnum meningioma trough a midline suboccipital approach
Figure 4: postoperative T1 Weighted sagittal MRI shows total removal of the lesion
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