Combined petrosal approach for a huge retroclival meningioma preserving the cranial nerves

Abstract

Surgery for petroclival meningioma is challenging because cranial nerve preservation during tumor removal can be very complex. For small- to medium-sized tumors, the anatomical relationship between tumor and neurovascular structures can be assessed before surgery. However, in large tumors, cranial nerves usually cannot be seen in preoperative images. The authors present a case of a 65-year-old woman who presented with gait disturbance and hearing loss and was diagnosed with huge retroclival meningioma involving the cavernous sinus, Meckel’s cave, and internal acoustic meatus. In this video, they explain the radiographical, anatomical, and surgical considerations and demonstrate the surgical technique.
The video can be found here: https://stream.cadmore.media/r10.3171/2022.1.FOCVID21221

Full text

Neurosurg Focus Video 6 (2):V4, 2022
NEUROSURGICAL
FOCUS
VIDEO
© 2022 The authors, CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/)
Transcript
This video will demonstrate the microsurgical resec-
tion of a huge petroclival meningioma with preservation
of the cranial nerves.
0:29 Patient Information. The patient is a 65-year-old
female who presented with gait disturbance.
0:35 Physical Examination. Her physical examina-
tion revealed right-side hearing loss, but no other neuro-
logical symptoms were observed.
0:41 Preoperative Imaging. Magnetic resonance im-
aging (MRI) demonstrated a well-enhanced mass occupy-
ing the cavernous sinus with extension to the clivus, in-
ternal auditory canal, and Meckel’s cave. Proton density
enhancement MRI usually indicates the location of the
cranial nerves as shown in the left-side MRI of another
patient. However, in this case, we can only identify both
optic nerves and facial nerve complexes before surgery.
1:10 Approaches. It was difcult to fully expose the
tumor with one approach alone, such as the anterior pe-
trosal, posterior petrosal, or retrosigmoid approach. The
posterior petrosal or retrosigmoid approach would pro-
vide only a limited surgical view of the tumor above the
Meckel’s cave or crossing the midline. Meanwhile, the an-
terior petrosal approach alone would show a limited surgi-
cal view of the tumor below the internal acoustic meatus,
though we may extend drilling to the rhomboid fossa. We
considered the combined petrosal approach the most ap-
propriate approach for this case.
1:47 Craniotomy Simulation. As you can see in this
real surgical view, the tumor is surrounded by the clivus,
brainstem, and petrous portion of the temporal bone.
When we simulate posterior petrosectomy and expose the
Trautmann triangle, we can see that the anterolateral por-
tion of the tumor is not exposed. Conversely, if we perform
only anterior petrosectomy, the posterolateral portion of
the tumor is not exposed. We thought that combined, the
petrosal approach can provide the optimal surgical cor-
ridor for this case. Additionally, the retrosigmoid approach
is not a good choice for this tumor because of the limited
unilateral view, as shown here.
2:32 Position and Skin Incision. The patient was in
the three-quarter position, and the head was rotated 90°
to the contralateral side. We prefer an inverted U-shape
skin incision for the combined petrosal approach. Motor,
somatosensory evoked potential (MEP and SSEP), facial
nerve EMG, facial MEP, and auditory brainstem responses
are monitored. We performed the whole procedure in 1 day.
2:56 Posterior Petrosal Approach. Mastoidectomy
was performed by the ENT department. The mastoid an-
trum and facial nerve were identied. Because the patient
had right-side hearing loss and the tumor crossed the mid-
line of the clivus, the translabyrinthine approach was pre-
ferred.
3:23 Anterior Petrosal Approach. The dura propria of
the greater super cial petrosal nerve and the V3 was sharp-
ly dissected. Using a cutting burr, a premeatal triangle was
SUBMITTED November 18, 2021. ACCEPTED January 21, 2022.
INCLUDE WHEN CITING DOI: 10.3171/2022.1.FOCVID21221.
Combined petrosal approach for a huge retroclival
meningioma preserving the cranial nerves
Dong-Won Shin, MD, and Chang-Ki Hong, MD, PhD
Department of Neurosurgery, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea
Surgery for petroclival meningioma is challenging because cranial nerve preservation during tumor removal can be very
complex. For small- to medium-sized tumors, the anatomical relationship between tumor and neurovascular structures can
be assessed before surgery. However, in large tumors, cranial nerves usually cannot be seen in preoperative images. The
authors present a case of a 65-year-old woman who presented with gait disturbance and hearing loss and was diagnosed
with huge retroclival meningioma involving the cavernous sinus, Meckel’s cave, and internal acoustic meatus. In this video,
they explain the radiographical, anatomical, and surgical considerations and demonstrate the surgical technique.
The video can be found here: https://stream.cadmore.media/r10.3171/2022.1.FOCVID21221
https://thejns.org/doi/abs/10.3171/2022.1.FOCVID21221
KEYWORDS meningioma; skull base; cranial nerves; microsurgery
Neurosurg Focus Video Volume 6 • April 2022 1

Shin and Hong
2Neurosurg Focus Video Volume 6 • April 2022
drilled, followed by removal of the postmeatal triangle and
petrous ridge. Then, a diamond burr was used to avoid in-
jury of the posterior fossa dura and inferior petrosal sinus.
3:51 Dura Incision. The presigmoid dura was incised
parallel to the sigmoid sinus as well as the temporal lobe
dura. The superior petrosal sinus was carefully ligated and
cut. It is essential to identify the location of the trochlear
nerve before cutting the tentorium, which is usually devi-
ated by the tumor.
4:15 Tumor Exposure and Removal. After cutting
the tentorial edge, the trochlear nerve was identied at the
lateral side of the tumor. We also opened the porus trigem-
inus to remove tumor tissue from inside Meckel’s cave. It
is essential to remove the tumor in Meckel’s cave because
trigeminal symptoms would not be relieved until we de-
compressed the tumor here. The trigeminal nerve was de-
viated to lateral side of the tumor in this case, which im-
plied this was true petroclival meningioma case. We can
see the brainstem at the medial side of the tumor with the
clear dissection plane. Tumor debulking helped to increase
the working space. The oculomotor nerve was identied
at the superior pole of the tumor. The ipsilateral posterior
cerebellar artery was carefully dissected and detached
from the tumor. The basilar bifurcation was easily identi-
ed by following the ipsilateral posterior cerebellar artery.
We usually pushed Surgicel between the tumor and nor-
mal structures and then created a space with cottonoid pat-
ties. Three-hands technique is useful when we remove the
tumor adjacent to neurovascular structure. Tumor decom-
pression and dissection were conducted between the criti-
cal vascular structures and nerves. Tumor debulking with
ultrasonoaspirator and piecemeal removal are mandatory
to secure surgical working space. The ipsilateral abducens
nerve was identied. The contralateral facial nerve was -
nally identied after we rem ove d al l tumor tissue. Residual
tumor tissue at the clivus and contralateral side were also
removed. The bilateral trigeminal nerves were microscop-
ically observed because the large tumor had occupied the
retroclival space. Both oculomotor nerves and posterior
communicating arteries were also identied. The ipsilat-
eral trigeminal, facial, and lower cranial nerves were well
preserved without signicant injury. Reconstruction was
performed with an articial dura substitute, brin sealant
patch, and brin glue. Lumbar drain was maintained for 3
days after surgery to prevent CSF leakage.
7:53 Postoperative MRI. Postoperative MRI revealed
near-total resection. Small residual tumor tissue was left at
the right cavernous sinus and the clivus. The patient had
oculomotor nerve paralysis immediately after surgery but
recovered after 6 months. Trochlear nerve palsy did not
improve, so she underwent surgery in the ophthalmologi-
cal department. Facial palsy was not observed, and the
other cranial nerves were neurologically intact.
8:22 Conclusions. Surgical resection of petroclival
meningioma is challenging regardless of the tumor size.
For cases of small- to medium-sized tumors, we can local-
ize the cranial nerves based on proton density gadolinium-
enhanced MRI. However, for large tumors, it is difcult to
preoperatively assess the tumor-nerve relationship. Kawase
et al.2,5 described that there is no uniform location of crani-
al nerves in petroclival meningiomas. In these cases, we as-
sess the location of the cranial nerves during surgery based
on the tumor growth direction and site of origin. Petroclival
meningiomas usually grow along the clivus, extend to the
middle fossa through Meckel’s cave, or extend below the
internal acoustic meatus. In each case, we carefully remove
the tumor and avert the cranial nerves to preserve them.
9:17 References1–6
Acknowledgments
Special thanks to the Department of Medical Contents, Asan
Medical Center.
References
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Disclosures
The authors report no conflict of interest concerning the materi-
als or methods used in this study or the findings specified in this
publication.
Author Contributions
Primary surgeon: Hong. Assistant surgeon: Shin. Editing and
drafting the video and abstract: both authors. Critically revising
the work: both authors. Reviewed submitted version of the work:
both authors. Approved the final version of the work on behalf of
both authors: Hong. Supervision: Hong.
Supplemental Information
Current Afliations
Dr. Shin: Department of Neurosurgery, Gil Medical Center,
Gachon University College of Medicine, Incheon, Republic of
Korea.
Correspondence
Chang-Ki Hong: Asan Medical Center, College of Medicine,
University of Ulsan, Seoul, Republic of Korea. yedamin@gmail.
com.