This document provides information about petroclival meningiomas and surgical approaches for their resection. It discusses the anatomy of the clivus, typical presentation of petroclival meningiomas, imaging characteristics, surgical techniques including the anterior petrosal, posterior petrosal, combined petrosal, and complete petrosectomy approaches, and complications. The key points are that petroclival meningiomas are benign tumors that commonly involve the trigeminal nerve and compress the brainstem. The surgical approach depends on tumor size and location as well as patient hearing.

1. DR. FARRUKH JAVEED
NEUROSURGERY JPMC
1

2.  It is pyramid-shaped
and is situated at the
base of the skull
between the sphenoid
and occipital bones.
 It has a base, an apex
and three surfaces
2

3. 3

4.  The clivus is that part of the skull base
situated between the foramen magnum
and the dorsum sellae.
 Formed from sphenoid and occipital
bones.
 The petroccipital fissure forms the
anterior lateral margin of the clivus,
while the synchondrosis between the
basioccipital and exoccipital bones forms
the posterior lateral margins.
4

5. 5
 The abducens nerve (cranial
nerveVI) tracks along the
clivus during its course.
Increased intracranial
pressure can trap the nerve
at this point and cause signs
of palsy.

6. 6

7. 7

8.  Benign tumor thought to arise from meningothelial arachnoid
cells
 account for approximately 20% of all primary intracranial
neoplasms.
 Women affected twice as often as men
8

9. 9

10.  extra-axial masses
 broad dural base
 homogeneous
 well defined margins
 buckling
 dural tail
 hyperostosis
 20-30% have some calcification
10

11.  Tumors arising from the upper two thirds of the clivus, at the
petroclival junction, and medial to the trigeminal nerve.
 They tend to compress the brainstem and basilar artery and
push these structures toward the contralateral side.
 These tumors are divided according to the location, structures
being compressed and involvement of the middle or posterior
cranial fossa.
11

12. 12

13.  The typical presentation of a petroclival meningioma is that of
an insidious onset. Most studies report that the period of
symptoms before diagnosis averages between 2.5 and 5
years, ranging from 1 month to 17 years.
 The features are usually due to the involvement of cranial
nerves, compression of brainstem or cerebellum and raised
ICP.
13

14.  Involvement of cranial nerves
 TheVth andVIIIth cranial nerves are the most frequently involved, up to 70%
 Facial nerve involvement occurs in about half of the patients.
 The lower cranial nerves are involved in about one third of cases, usually
associated with the larger tumors extending inferiorly.
 Cerebellar compression
 Gait ataxia in 70% of the patients.
 Headache is seen in about 70% of the patients.
14

15.  Brain stem compression
 Long tract signs and somatosensory deficits.
 Spastic paresis has been reported in 15% to 57% of patients
 Somatosensory deficits are identified in 15% to 20%.
 Increased intracranial pressure
 Decreased consciousness
 Blurred vision
 Vomiting
 Dementia
15

16.  The audiogram:
 will not only provide a useful baseline of the patient’s cranial nerve
VIII function, but it will also give insight into the limitations of the
surgical approach.
 Neuro-ophthalmologic examination:
 Preoperatively it detects cranial neuropathies involving CN III, IV,
and/orVI.
16

17.  CT brain
 MRI Brain with contrast
 MR Myelogram
 MRV
 Cerebral angiogram
17

18.  slightly hyperdense to normal brain
 bright and homogeneous contrast enhancement
 hyperostosis
 Anatomy of the inner ear
 Height of jugular bulb
 Pneumatization of mastoid bone
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19.  T1 : usually isointense to grey matter, delineate tumor, its
relationship to other structure
 T2 : usually isointense to grey matter, hyperintense to grey matter,
arachnoid cleavage plane, brain stem edema and infiltration
 Post-contrast: usually intense and homogeneous enhancement
 Flow void : location of major vertebrobasilar vessel
 The MR spectroscopic features of meningiomas include
absence of N-acetylaspartate(NAA) and elevations of choline
peaks. Alanine has been suggested to be a specific marker for
meningiomas, but with variable sensitivities.
19

20.  Torcula, transverse sinus, sigmoid sinus
 Vein of Labbe (posterior temporal venous drainage)
20

21.  Tumor blood supply
▪ meningohypophysial trunk of the internal carotid artery
▪ the posterior branch of the middle meningeal artery
▪ the meningeal branch of the vertebral artery
▪ the clivus artery from the carotid siphon
▪ the petrosal branches of the meningeal arteries
▪ the ascending pharyngeal branches of the external carotid artery
 Mass effect on vertebrobasilar systems
21

22.  Surgery is the mainstay of petroclival meningioma treatment.
 It can be done as
 Conventional surgery
 Stereotactic radiosurgery
22

23.  The principles of petroclival meningioma resection are based
on using a lateral skull base approach while avoiding brain
retraction; avoiding venous injury, especially the vein of
Labbé; and connecting the middle and posterior fossa by
drilling the petrous ridge and splitting the tentorium.
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24.  Goal of surgery is complete resection of the tumor without causing additional
deficits to the patient.
 Tumor with brain stem compression
 decompression with either total or subtotal excision
 Tumor with neurovascular invasion
 Excision of tumor that leaves the part infiltrating the neurovascular structure
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25. 25

26.  Somatosensory evoked potentials (SSEPs)
 Record peripheral nerve afferent
 Motor evoked potentials (MEPs)
 Recording electromyogram activity in muscle
 Brain stem auditory evoked potentials (BSAEPs)
 Cortical response to auditory stimuli
 Electromyography (EMG)
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27.  Anterior petrosal approach
 Posterior petrosal approach
 Combined petrosal approach
 Complete petrosectomy
27

28. 28

29.  Zone I (upper zone)
 dorsum sellae to the upper border of the IAC
 exposed via the Kawase approach (anterior petrosal approach)
 Zygomatic osteotomy can be added
 Zone II (middle zone)
 IAC to the upper border of the jugular tubercle
 exposure provided via the posterior petrosal approach
 tumor involve Zone I and II : combined petrosal approach
 Zone III (lower zone)
 jugular tubercle to the lower edge of the clivus
 Exposed via lateral suboccipital–transcondylar approaches
29

30. • Petroclival angle
– angle between the petrous bone
and the clivus at the level of IAC
• Central clival depression
– relationship between intermeatal
plane(superior) and jugular
tubercle(inferior)
• The less obtuse the petroclival
angle, the more difficult the
exposure of the central clival
depression 30

31.  The anterior petrosal approach is best suited for smaller petroclival
meningiomas that do not extend lateral to the internal auditory
meatus (IAM).
 The anterior petrosal approach is limited in its ability to expose tumors
deeper in the posterior fossa, and requires more manipulation of the
trigeminal nerve. During this approach, the fifth cranial nerve is
exposed and is the center of the exposure.Tumor resection occurs in
the spaces above and below the nerve.
31

32.  The anterior petrosal approach has the added benefit of
allowing visualization of the midline clivus.
 If a tumor extends more medially or contralaterally, the
posterior approach may yield limited exposure, and thus an
anterior middle fossa approach should be used alone or as an
addition to a posterior petrosal approach.
32

33.  allows exposure
 the middle fossa floor
 the petrous bone apex,
 zone I of the petroclival region
 subtemporal or frontotemporal craniotomy and anterior petrosectomy
 lumbar drain
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34.  Position
 Supine position and rotate 90
 Ipsilateral shoulder is elevated
 Head tilt 15 degrees downward
 Patient’s upper back is elevated 25-30 degrees
 Skin incision
 initiated posterior to the midpoint of the mastoid process extends superiorly and
anteriorly
 traversing the superior temporal line and ending at the middle of the zygomatic
arch for a subtemporal anterior petrosal approach
34

35.  Subtemporal approach
 Myocutaneous flap reflex inferiorly
 Rectangular craniotomy along the squamosal suture
 Zygomatic osteotomy
 Drilled floor of middle fossa
 Key : preserve dura and remain extradural
 Frontotemporal craniotomy approach
 Skin flap extend anteriorly
 Mycutaneous flap reflex anteroinferiorly
 Sphenoid wing complete drill
35

36.  The dura is elevated from the middle
fossa floor, and petrous bone via a
posterior to anterior approach;
elevation starts at the arcuate eminence
and proceeds anteriorly
 The middle meningeal artery is
controlled with bipolar cautery and
sectioned, the foramen spinosum is
packed with bone wax
 Greater superficial petrosal
nerve(GSPN) is identified and keep
intact : dissection follows the GSPN
from posterior to anterior until it
courses under the third division of the
trigeminal nerve (V3)
36

37.  Anteriorly, the mandibular division (V2) is
identified at the foramen rotundum
 Dissection continues medially to the
petrous ridge indenting the superior
petrosal sinus
 Separation of the dura propia continues
until the connective tissues sheath over
V2,V3 and the Gaserian ganglion is
visible(Meckel’s cave)
37

38.  Drilling of the IAC continues to the bone crest dividing the facial nerve
and the superior vestibular nerve
 The bone overlying the cochlea is drilled until the cochlea appears as a
blue line
 After identify of the dura covering the IAC posterior, drilling is
continued until:
 GSPN (preserved) laterally
 the petrous segment of the internal carotid artery anterolaterally
 V3 anteriorly
 the superior petrosal sinus medially
 the posterior fossa dura and inferior petrosal sinus inferiorly
38

39.  The inferior temporal lobe dura is open above and parallel to the
superior petrosal sinus.The dura is reflected inferiorly
 The superior petrosal sinus is secured with titanium hemoclips and is
split
 The tentorium is cut medially toward the tentorial incisura posterior to
the dural entry of the trochlear nerve
 The posterior fossa dura is further split inferiorly
39

40.  After completion of surgical resection
 Watertight dural closure is done.
 The IAC bony opening is plugged with a small piece of fat or muscle
 The dura is approximated utilizing a graft.
 If there is a big filling defect, it can be judiciously obliterated with pieces of fat
graft to prevent postoperative fluid collection and cerebrospinal fluid (CSF) leak
40

41.  The posterior petrosal approach allows
visualization of tumors deeper within the
posterior fossa, lateral to the IAM.
 Temporal craniotomy + presigmoid
craniectomy + a small lateral retrosigmoid
craniectomy
 Depending on the preoperative hearing
 retrolabyrinthine or translabyrinthine bony
temporal bone drilling is added
41

42.  The petrous resection is retrolabyrinthine, allowing for preservation of
hearing.
 Resection of the labyrinth and the cochlea increases the operative
exposure, but hearing is sacrificed, and the facial nerve is at risk of
being weakened.
 Sectioning of the superior petrosal sinus and tentorium, and a relaxing
incision in the dura above the lateral transverse sinus
 frees the sigmoid sinus and allows mobilization of the sigmoid sinus posteriorly
to expand the presigmoid space : crucial step
42

43.  Position
 Same in anterior petrosal approach
 Lateral oblique position
 Skin Incision
 three fingerbreadths circumferentially around the edge of the ear pinna
43

44.  The transverse sinus and the transverse–sigmoid junction are dissected from the
overlying bone
 Retrolabyrinthine Mastoidectomy
 After drilling the bone over the sinodural angle, the sigmoid sinus, superior
petrosal sinus, and posterior semicircular canal are exposed
44

45.  Dura openings
 Below temporal lobe : parallel to the superior petrosal sinus
 Posterior fossa dura in presigmoid space : longitudinally between superior
petrosal sinus and the jugular bulb
 Gentle traction on temporal lobe and cerebellum :
superior petrosal sinus is sectioned and clipped
 Incision dura along transverse sinus
 The tentorium is sectioned into the incisura at a point posterior to entrance of
the trochlear nerve
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46. 46

47.  Closure
 Pericranium or a synthetic dural graft for close
 Open mastoid air cell : wax
 The mastoidectomy : abdominal fat graft and sprayed with fibrin
glue
 Bone flap closed with titanium plates
 Temporalis m. is closed
 Keep lumbar drain for 48 hrs
47

48.  The combined petrosal approach is optimal for patients with
large petroclival tumors who have serviceable hearing.
 This exposure takes advantage of the benefits of both anterior
and posterior petrosal approaches, while saving hearing.
 In addition, this approach allows exposure of the petrous apex
and the Meckel cave.The ability to expose the ventral
brainstem allows visualization of the BA and perforating
vessels, providing a safer approach to resection.
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49. 49

50. 50

51.  In patients with large tumors and loss of hearing, the
complete petrosectomy allows the most extensive surgical
exposure.
 The limitation of this approach is the longer preparation time
required to drill the entire petrous bone.
 There is risk of injury to the facial nerve because the exposure
requires skeletonizing the nerve along its course through the
temporal bone. Leaving a thin shell of bone surrounding it
during exposure can decrease the risk of facial nerve injury.
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52. 52

53.  CSF leakage (10%)
 Trigeminal neuralgia
 Hearing loss (8%)
 Facial weakness
 Hydrocephalus
 Wound dehiscence
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54. 54

55.  Preoperative (nf) and
postoperative (lower row)T1-
weighted MR images obtained
a patient who underwent
resection of a petroclival
meningioma via an anterior
petrosal approach.The tumor
is an example of a small
petroclival mass located
superiorly to the IAM, allowing
complete resection via the
anterior approach.
55

56.  Preoperative and
postoperative MR images
demonstrating a large
petroclival meningioma
extending below the IAM in a
patient with intact hearing,
prompting a posterior
petrosal approach for
resection.
56

57.  Preoperative (A and B) and
postoperative (C) MR
images demonstrating
complete resection of a
large petroclival
meningioma via a
combined petrosal
approach.
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