2. Great teachers – All this is their work .
I am just the reader of their books .
Prof. Paolo castelnuovo
Prof. Aldo Stamm Prof. Mario Sanna
Prof. Magnan
3. For Other powerpoint presentatioins
of
“ Skull base 360° ”
I will update continuosly with date tag at the end as I am
getting more & more information
click
www.skullbase360.in
- you have to login to slideshare.net with Facebook
account for downloading.
9. Recurrent Rathke's Cleft cyst,previously operated in Russia by external
approach.Case done with Dr.V.S.Mehta sir...Showing the beautiful anatomy of
suprasellar area. Note the loss of right optic nerve fibers due to compression
of the cyst.
17. The carotid bends laterally in the nasopharynx before entering the petrous temporal bone. It
then swings anteriorly before becoming the paraclival carotid in the floor of the sphenoid and
progresses vertically into the cavernous sinus and then enters the anterior cranial fossa giving off
the middle cerebral artery (MCA) to become the anterior cerebral artery.
18. Dry bone specimen following a frontal drillout procedure. This specimen clearly shows the close
relationship between the frontal sinuses and the cribriform plate, and hence the advantage of the
drillout procedure for anteriorly based lesions. AT of FS, anterior table of frontal sinus; PT of FS,
posterior table of frontal sinus; FC, foramen cecum; CP, cribriform plate; CG, crista galli.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31. Always one cell [ AEC ] present anterior to AEA .
Cadaveric dissection image of the left ethmoid cavity revealing the anterior ethmoidal
artery (AEA) located one anterior ethmoidal cell (AEC) posterior to the frontal sinus
(FS). OF, orbital fat; PO, periorbita.
32. .
• When approaching an olfactory groove
meningioma, regardless of approach, both the
extra- and intradural arteries associated with
the tumor must be controlled. The anterior
and posterior ethmoidal arteries provide the
major extradural blood supply to the tumor
33. Anterior ethmoidal artery has to be
cauterized on cerebral side , if you
do on orbital side it may retract &
cause retro-orbital haemorrhage
34. Cadaveric dissection image demonstrating the left anterior ethmoidal artery (AEA) and nerve (AEN) running
across the skull base toward the middle turbinate (MT) attachment. Here it can be seen dividing into several
branches including the anterior falcine artery (AFA) to supply the falx cerebri. LP,
lamina papyracea. - In Olfactory meningioma surgery the small, falcine arterioles that feed the tumor
can be coagulated. Sacrificing these arteries early in the dissection provides further tumor
devascularization.
35. Cadaveric dissection illustrating the anatomy of the anterior skull base following
partial resection of both middle turbinates (MT) and nasal septum. The communal
frontal sinus (FS) ostium can be seen anteriorly with both fovea ethmoidalis (FE)
exposed. The lateral margins are the lamina papyracea (LP) and posteriorly the
planum sphenoidale (PS) can be seen. OF, olfactory fossa; AEA, anterior ethmoidal
artery; PEA, posterior ethmoidal artery; AEN, anterior ethmoidal nerve; PEN, posterior
ethmoidal nerve.
37. The anterior attachment of the falx cerebri (FC) to crista galli (CG) is seen. Note the superior
sagittal sinus (SSS) running in the superior aspect of the falx cerebri within the inferior sagittal
sinus (ISS) in the lower margin of the falx cerebri. The inferior sagittal sinus becomes the straight
sinus (SS) after it joins with the great cerebral vein.
39. The skull base is placed under traction and the remaining posterior falx
cerebri still holds the skull base. This needs to be cut
before the skull base can be dropped into the nose.
40. I THINK AFTER SEPERATION OF FRONTAL LOBES WE SEE ANTERIOR CEREBRAL
ARTERIES - REFER
Cadaveric dissection image: the skull base has been removed affording a view of the inferior
aspect of both anterior cerebral lobes. The olfactory bulbs (OB), branches of the anterior cerebral
artery (ACa), and cut inferior aspect of the falx cerebri (FC) can be seen. FS, frontal sinus; AEA,
anterior ethmoidal artery; LP, lamina papyracea. -
43. Dear surgeons cadeveric craniectomy see frontal lobes gyrus recti falx
fronto polar arteries draff type3 all in one – Dr. Sree Ram Murthy
44.
45.
46. F = Frontal , LP = Lamina papyrecea ,
GR = Gyrus rectus
47.
48. Two-suction technique for tumor resection. Note that the righthanded suction is providing
traction while the other suction is dissecting soft tumor.
Microneurosurgical techniques for tumor removal
include the internal debulking of the tumors,
followed by the mobilization of the tumor capsule to
allow early identification and extracapsular
dissection of neurovascular structures, and the
coagulation and removal of the remaining capsule.
This sequence is repeated multiple times until final
sharp dissection of the residual capsule is completed.
These time-proven techniques are designed to
minimize the risk of injury to important structures
and are critical elements for the removal of any
tumor with any surgical approach. Endoneurosurgical
tumor removal adheres to the same dissection
principles of open approaches and avoids blind
dissection of tumors from vessels and nerves. Under
no circumstances are tumors extracted by pulling
without seeing the underlying structures. If the
technique above cannot be performed the resection
mustbe abandoned.
51. Suprasellar/transplanum
approach:
Drill the bone of the planum sphenoidale until
paper-thin.
It is important to recognize that the planum has a
rhomboid geometry, bound by the optic nerve
canals laterally and the tuberculum sella strut
posteriorly.
The bone of the planum is removed in an anterior to
posterior direction displacing it inferiorly to gain
distal access.
The dura is very adherent over this area. Removal
of the bone using rongeurs in a posterior to
anterior direction universally results in a dural
injury (before intradural control of the anatomy).
The tuberculum strut needs to be drilled until very
thin; then, it can be fractured and removed. This will
expose the superior intercavernous sinus that can be
then be coagulated and/or clipped and divided &
surgiflo applied if it is still bleeding .
Open the dura and identify the optic nerves, (RON &
LON) chiasm and tracts, the infundibulum, and ICAs.
52. Anterior and posterior
ethmoid arteries control:
Identify the anterior (AEA)
and posterior ethmoid
arteries
(PEA) inside the orbital cavity,
displacing the periorbita
laterally to assist with their
visualization.
Note the orientation of the
arteries.
Uncap their bony canal,
dissect the neurovascular
bundle
out of the canal and transect
them.
53. Frontal sinusotomy (Draf III):
Enlarge the nasofrontal recess
anteriorly and medially (drill or
rongeurs) to reach the nasal septum
(Draf IIb).
Extend the resection of the posterior
nasal septum to
reach the level of the anterior wall of
the frontal sinus.
At this point you should be able to
see both nasofrontal recesses from
either side of the nose.
Remove the floor of the frontal
sinuses across the midline
while remaining anterior to the
posterior wall of the
frontal sinus and the crista galli.
Remove the “frontal
beak” and extend the resection of the
floor anteriorly until
you can visualize the anterior wall of
the frontal sinus.
54. Anterior craniofacial resection (Trans-
cribiform Approach):
Resect any remnants of the superior
attachments of the posterior nasal
septum, middle and superior turbinates.
Complete a “sequential layered
resection” removing the
mucoperiosteum and olfactory
filaments; then, the bone of the fovea
ethmoidalis and cribiform plate; and
then, the dura:
a) remove the mucosa with through-
cutting instruments.
b) drill the fovea ethmoidalis medial to
its junction with the roof of the orbit and
the cribiform plate until they are paper-
thin and remove with blunt instruments
c) drill out crista galli.
55. Incise the dura along the lateral edge of the bony defect and join
the longitudinal incisions anteriorly with a horizontal incision.
Extend the latter medially to reach the falx cerebri bilaterally.
56. The falx cerebri can be transected in an anterior to posterior
fashion, only after the identification of the anterior fossa
vasculature ( frontopolar and fronto-orbital vessels).
57. Sharp dissection [ key principle in transcibriform approach ] is utilized to allow
for extracapsular dissection. Note, that the suction provides retraction of the tumor (T) and
tension along the band. The fronto-polar artery (FPa) is preserved
along the frontal lobe (F) while an olfactory groove meningioma (T) is being removed.
58. A blunt dissector is being utilized to establish a dissection plane
between a left olfactory bulb (OB) invaded by cancer and the gyrus
rectus (GR).
61. Recurrent artery of heubner originates
near Acom
(A) The middle cerebral artery (MCA) gives rise to the lateral lenticulostriate arteries
(LLA) at the bifurcation complex. The medial lenticulostriate arteries (MLA) arise from
the proximal section of A1. At the juncture of A1-AComm-A2 the recurrent artery of
Heubner (RAH) is given off. AComm completes the anterior portion of the circle of
Willis and has several perforating vessels ( Acomm Perf) that head posteriorly. In the
first 5 mm of A2 the orbitofrontal ( OF) artery is given off with the frontopolar (FP)
artery staying more medial. (B) A clinical picture after removal of a tuberculum sella
meningioma with a well-defined display of the anterior cerebral arteries.
62. In the lateral border of the chiasmatic cistern the first part of
the ICAi is visible.
Dry bone dissection image taken with a 30-degree endoscope demonstrating the fovea
ethmoidalis (FE) and cribriform plate (CP) junction with the planum sphenoidale (PS). This is
marked approximately by the posterior ethmoidale artery (PEA). ISS, intersinus septum of
sphenoid sinus; ON, optic nerve; CCA, anterior genu of the intracavernous carotid artery.
63. Preoperative CT angiogram showing the close association of the tumor
capsule of an olfactory groove meningioma with the anterior
cerebral arteries (arrows). – sometimes ACA present in the posteior part of
the tumor
64. In contrast, craniopharyngiomas within the pre-chiasmatic space can be removed
via a supraorbital or endonasal route, while tumors with lateral extensions or
supra-chiasmatic extensions can be most effectively removed by a supra-orbital
or lateral transcranial approach. – from craniopharyngioma book
65. When the ACAs present in the posterior part of the
tumor BIFRONTAL approach is used – by Dr.Lee
• Add video clipping
66. MRI scans show the A1 (solid white arrow) leaving the middle cerebral artery juncture toward the AComm (dashed
white arrow) with the A2s (black arrow) progressing superiorly. These vessels are all within the substance of the tumor.
The clinical dissection of this tumor is seen in (C) and (D) with tumor encompassing the perforators (Perf) coming off
the AComm. Once all tumor had been removed the vascular complex with A1-AComm,-A2 and the important branch
of A1, the recurrent artery of Heubner ( RAH), and the A2 branch, orbitofrontal (OF) artery, are clearly visible.
67. The lateral limit of resection for olfactory groove meningiomas is the midorbital
vertical meridian (fig. 5). This limitation is created by, as we believe most limitations
are, a nerve, in this case the optic nerve. Removal of the lamina papyracea allows
gentle retraction of the periorbita and orbital contents to allow access to the orbital
roof out to the midorbit.
Coronal post-contrast T1-weighted MRI showing the lateral limit of resection at the midorbital
vertical meridian (dotted line). b Postoperative post-contrast T1-weighted MRI showing complete
resection out to midorbit via EEA.
68. Endoscopic endonasal view of the
anterior
skull base following the sinonasal
portion
of the approach. Dashed lines
represent the
osteotomies to be performed for
dural access.
Endoscopic endonasal view of
the right
posterior ethmoidal artery for
bipolar coagulation
and ligation.
69. • There are often multiple fine falcine arterioles
that provide additional blood supply to olfactory
groove meningiomas. Following tumor debulking
on either side of the falx, these arterioles can be
carefully transected and coagulated during the
resection of the falx to provide further tumor
devascularization.
• The tumor should not be detached anteriorly
before all of the internal debulking is complete,
as frontal lobe descent can obscure visualization.
70. In coronal MRI scans (A,B) and parasagittal MRI (C) the two consistencies of tumor are visible.
The soft tumor is marked with a solid white arrow whereas the calcified tumor is marked with a
broken white arrow. In coronal CT scan (D) the calcified part of the tumor is clearly seen (white
broken arrow). (A,B) Brain edema is indicated with a solid black arrow. The other important
feature seen in (C) is the close approximation of the tumor to the posterior wall of the frontal
sinus (broken black arrow). This means that the anterior osteotomy should be through the
posterior wall of the frontal sinus.
74. For Other powerpoint presentatioins
of
“ Skull base 360° ”
I will update continuosly with date tag at the end as I am
getting more & more information
click
www.skullbase360.in
- you have to login to slideshare.net with Facebook
account for downloading.
