Name:
10.3171/2023.10.FOCVID23118
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10.3171/2023.10.FOCVID23118
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T00H10M28S
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https://stream.cadmore.media/player/6b29440a-b481-43b3-a7c3-73484b93e2f5
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https://cadmoreoriginalmedia.blob.core.windows.net/6b29440a-b481-43b3-a7c3-73484b93e2f5/4. 23-118.mp4?sv=2019-02-02&sr=c&sig=xyv572sKxscz7vcFxFt0Oq4ayDjZn58tHa8lY5AvHcU%3D&st=2024-12-10T07%3A50%3A20Z&se=2024-12-10T09%3A55%3A20Z&sp=r
Upload Date:
2023-12-08T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING]
MARTIN LEHECKA: Exoscopic extradural anterior clinoidectomy. This two-dimensional operative video shows a right optic nerve decompression by extradural anterior clinoidectomy, and subsequent resection of a small clinoidal meningioma (Al-Mefty type III) using an exoscope (Aesculap AEOS). The patient is a 50-year-old woman with a 12-month history of progressive visual acuity impairment and papillary atrophy in the right eye, confirmed by ophthalmologic examination.
MARTIN LEHECKA: No other neurological symptoms were reported. The MRI shows a right-sided anterior clinoid meningioma classified as Al-Mefty type III. The tumor is rather small, but it is located just at the orifice of the optic canal, as seen on the T1-weighted images. On the T2 images, we can see that the tumor is pushing the right optic nerve laterally and it is growing into the optic canal, compressing the nerve at this level.
MARTIN LEHECKA: Considering the progressive visual worsening, we decided to decompress the right optic nerve by opening of the bony optic canal, and removing the intradural part of the tumor through a mini-pterional approach combined with extradural anterior clinoidectomy. The extradural approach is used to gain access to the optic canal along its whole length, all the way to the orbital apex.
MARTIN LEHECKA: Patient's head is fixed in a Sugita head frame, rotated 50 to 60 degrees to the contralateral side, and slightly extended. After minimal shaving, a curvilinear skin incision is planned just behind the hairline from the midline towards the right ear, up to three centimeters cranial to the origin of the zygoma. After submuscular dissection, a Helsinki-style mini-pterional approach is used with the whole bone flap placed under the temporal muscle.
MARTIN LEHECKA: Medial and lateral craniotome cuts are connected by a groove along the frontal basal part, crossing the sphenoid ridge. The bone flap of three to four centimeters is then cracked along this groove and elevated. A 3D CTA reconstruction shows the surgical steps during drilling of the bony segments needed to reach the full removal of the anterior clinoid process. The blue area represents the sphenoid ridge that has to be drilled first to reach the medial clinoid structures, consisting of the superior and inferior roots.
MARTIN LEHECKA: The superior clinoidal root (light green area) connects the anterior clinoid process to the planum sphenoidale and forms the roof of the optic canal, together with the falciform ligament. The inferior clinoidal root (red area) consists of the optic strut that connects the clinoid to the sphenoid body, resulting in an inferolateral wall of the optic canal.
MARTIN LEHECKA: This structure also divides the optic canal from the superior orbital fissure. The 3D rotational view shows the relationship of the anterior clinoid process, the optic canal, and the superior orbital fissure. It also shows the relationship with the cavernous and clinoidal segments of the internal carotid artery (ICA), the C4, and the C5 segments according to the Bouthillier classification.
MARTIN LEHECKA: The OR setting, exoscope position, and surgeon ergonomics are shown here. After flattening of the pterion, the sphenoid ridge is progressively drilled in the proximal direction with a five-millimeter coarse diamond. The orbito-meningeal artery is exposed, coagulated, and cut.
MARTIN LEHECKA: The drilling is continued medially with the four and three millimeter fine diamond until the meningo-orbital band. The meningo-orbital band is cut, allowing for detachment of the dura of the temporal fossa from the lateral wall of the cavernous sinus, as shown by the dotted line and orange arrows. This step exposes the clinoidal body highlighted in blue.
MARTIN LEHECKA: The drilling is then shifted more medially on the most superior part of the anterior clinoid process (light green area) with the aim to drill along the optic nerve, starting from lateral to medial and posterior to anterior. Drilling is done under high magnification to have better control over the underlying structures. The expected location of the optic nerve is shown in violet color, the residual superior root in yellow, the optic strut in red, and the tip of the clinoid process in green.
MARTIN LEHECKA: The drilling is continued with fine 2 millimeter diamond until only a translucent sheet of bone remains on top of the optic nerve. This bony shell is then removed with a micro dissector. Now, the clinoidal body is free from the planum sphenoidale, and the superior part of the optic nerve is already decompressed.
MARTIN LEHECKA: Next aim is to decompress also the lateral wall of the optic canal by drilling the optic strut shown in red color next to the optic nerve shown in violet. The fine adjustments of the exoscope camera angulation using a foot pedal is very helpful to gain optimal view for drilling. With this drilling completed, the optic canal is already decompressed by nearly 180 degrees, and the tip of the anterior clinoid process shown in dark green is free from its bony attachments.
MARTIN LEHECKA: What is left is to remove the tip of the anterior clinoid process, as shown in light green color. This is achieved by first cavitating the bone from inside and then mobilizing the thin crust from its adhesions to the dura. Extra care is needed not to injure the internal carotid artery lying underneath. Removal of the remaining bone piece leaves the space lateral to the optic nerve completely decompressed.
MARTIN LEHECKA: The graphic shows the dura covering the right optic nerve in violet, remnant of the superior glandular root in yellow, remnant of the optic strut in red, and course of the cavernous segment of the internal carotid artery in pink. The fold of the falciform ligament is free and nicely visualized.
MARTIN LEHECKA: With the extradural work finished, it is time to move intradurally. The dura is opened in a curvilinear fashion, showing the Sylvian veins, the frontal and temporal lobe. We move up frontally and immediately reach the attachment of the meningioma at the frontal basal dura next to the optic nerve. Laterally, we identify supraclinoidal ICA and the lateral part of the optic nerve, which is compressed by the tumor.
MARTIN LEHECKA: Using bipolar forceps and suction, the tumor is first detached from its origin and then removed in several pieces to decompress the optic nerve. After removal of the exophytic intradural part of the meningioma, what is left of the tumor is the part growing into the optic canal. It is usually at the level of the falciform ligament where the optic nerve is compressed the most.
MARTIN LEHECKA: At this stage of the surgery, due to the previous extradural optic canal decompression, there is already some extra space. Still, to remove the remaining part of the tumor, the falciform ligament is cut along the optic nerve, and the optic nerve is decompressed further. The cutting of the falciform ligament can be performed using either microscissors or with an angled knife. We can see how the optic nerve has slightly darker color at the site where the maximal compression was at the level of the falciform ligament.
MARTIN LEHECKA: The small tumor remnants are gently dissected away from the nerve, sparing its vascularization. The course of the ophthalmic artery is usually inferolaterally to the optic nerve at the beginning of the optic canal, as in this case. So dissecting above and medially to the nerve with a blunt hook was relatively safe. The optic nerve is now free, and we can also see the intradural course of the ICA, the origin of the posterior communicating artery, as well as the right-sided olfactory nerve.
MARTIN LEHECKA: Before the final closure, we use the possibility to inspect the most distal part of the optic canal from extradural direction for any tumor remnants. For this, the dural cut along the nerve is enlarged a little.
MARTIN LEHECKA: At the start of closure, a thin sheet of Gelfoam is inserted intradurally. Autologous fat is then used to fill the epidural space and cover the small dural defect. The dura is sutured in a watertight fashion. Bone flap is attached with two cranial fixes, and the rest of the closure is carried in layers. Patient was discharged on the third postoperative day.
MARTIN LEHECKA: At a three-month ophthalmological follow-up, the findings were the same as before the surgery. There had been no further progression of the symptoms of the right eye. Unfortunately, there was no major improvement, as the preoperative compression damage to the nerve had probably already been irreversible.
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