Name:
                                10.3171/2023.10.FOCVID23125
                            
                            
                                Description:
                                10.3171/2023.10.FOCVID23125
                            
                            
                                Thumbnail URL:
                                https://cadmoremediastorage.blob.core.windows.net/1c9af21d-d5d7-48e4-ad5b-e66e3efc792d/videoscrubberimages/Scrubber_601.jpg
                            
                            
                                Duration:
                                T00H10M27S
                            
                            
                                Embed URL:
                                https://stream.cadmore.media/player/1c9af21d-d5d7-48e4-ad5b-e66e3efc792d
                            
                            
                                Content URL:
                                https://cadmoreoriginalmedia.blob.core.windows.net/1c9af21d-d5d7-48e4-ad5b-e66e3efc792d/6. 23-125.mp4?sv=2019-02-02&sr=c&sig=n0VExii%2Bo0E17i%2Bqp0BKfvIOLzKDwObpONRzkJ6pyp0%3D&st=2025-10-31T15%3A05%3A27Z&se=2025-10-31T17%3A10%3A27Z&sp=r
                            
                            
                                Upload Date:
                                2023-12-04T00:00:00.0000000
                            
                            
                                Transcript:
                                Language: EN. 
Segment:0 . 
[MUSIC PLAYING]    
SPEAKER: This 2D operative video  shows the use of digital 3D   Exoscope in the removal of  a giant olfactory groove   meningioma, through a lateral  supraorbital approach.   The patient is a  57-year-old woman,   with a 12 month history of  progressive visual field   impairment and decreased vision  on the right eye, anosmia,   and apathy.   The MRI shows a giant  olfactory groove meningioma,   with an extensive frontal  lobe compression and edema.   On the T2 coronal images, we  can see that the A1-ACom complex   is displaced cranially  to the right side,   while the optic chiasm is  shifted inferioposteriorly.    
SPEAKER: The lesion appears vascularized,  with the main feeders coming   from ethmoidal arteries,  through the skull base   at the level of the crista  galli, an extensive network   of enlarged veins on  the tumor surface.   There are areas where  arachnoid plane can   be seen between the  tumor and the brain,   so at least some parts  of the tumor surface   will not be completely  attached to the pial surface.   Pericallosal arteries and  some of their branches   are running along the  posterior and superior surface   of the tumor.    
SPEAKER: Even for giant anterior  skull base tumors,   we prefer to use small frontal  lateral approaches instead   of large bifrontal approaches;   since they are  faster to perform,   they provide good exposure of  all the necessary structures   and frontal sinuses  are left intact.   When choosing the side of  the frontal lateral approach,   several factors  must be considered.   In this case, more  of the tumor mass   is located on the left  side of the midline.   This would favor a  left-sided approach.    
SPEAKER: However, the asymmetry  and inclination   of the anterior skull base  at the crista galli region   is such that the  right-sided approach   will expose the  main tumor feeders   for early devascularization much  better than what a left-sided   approach would offer.   Also, the pericallosal  arteries and the ACom complex   are displaced to  the right, so they   will be easier to control  from the right-sided approach.    
SPEAKER: Moreover, the already  existing visual impairment   of the right eye  is also in favor   of the right-sided approach.   A right-sided lateral  supraorbital approach   was selected for this case.   The patient's head is fixed in  a Sugita head frame, rotated   about 50 degrees to  the opposite side,   and tilted laterally  about 10 degrees.   After minimal shaving, a  curvilinear skin incision   is made at the hairline,  running from the midline   towards the ear, stopping  at about 4 centimeters   cranial to the  origin of the zygoma.    
SPEAKER: A small part of the  anterocranial part   of the temporal muscle  is incised and turned   frontobasally. One  burr hole is planned  under the temporal muscle.   Medial and lateral  craniotomy cuts   are connected by a groove  along the frontalbasal part,   close to the floor of  the anterior fossa.   The bone flap of  about 4 centimeters   is then cracked along  this groove and elevated.    
SPEAKER: High speed drill is used to  reach the floor of the anterior   fossa and to flatten  the sphenoid ridge   at the lateral edge  of the craniotomy.   The dura is cut in a  curvilinear fashion   and tack-up sutures are placed  to prevent epidural oozing.   Intradurally, the first step  will be tumor devascularization   and detachment from the  anterior skull base.   On the left-sided  image, the yellow area   represents the main area  of the tumor attachment   and the red dotted line the  area of bony hyperostosis.    
SPEAKER: The blue area is  the crista galli,   with falcine attachment  colored in green.   The hyperostosis on  the preoperative images   extended from the  crista galli posteriorly   to the planum  sphenoidale, especially   on the left side of the  anterior skull base.   The image on the  right shows how even   a rather small frontal  lateral craniotomy   provides wide exposure at depth  due to the keyhole effect.    
SPEAKER: This next image demonstrates  how all the targeted areas   can be reached and  properly visualized   by translational and  angular movements   of the exoscopic camera.   This is one of the  greatest advantages   of the exoscope compared  to the surgical microscope.   All these different  viewing angles   can be achieved only by  movement of the camera   without any positional  changes of either the surgeon   or the patient.    
SPEAKER: The OR setting and the  ergonomics of the surgeon   are shown here.   After introducing the exoscope,  (Aesculap Aeos), we move   subfrontally towards  the tumor attachment.   We can immediately see a clear  borderline between the tumor   and the brain.   We follow the flow  of the anterior fossa   and progressively coagulate  and cut the tumor attachment.   The first aim is to reach the  ipsilateral optic and carotid   cisterns.    
SPEAKER: Here we can on one hand  secure the right optic nerve,   but also we can open the base  assistance to release CSF   for gaining additional space.    The dissection is  then oriented more   medially as demonstrated  by the blue cone.   The next target area  is the crista galli   and the hyperostotic bone, where  the main feeders of the tumor   are.    
SPEAKER: The tumor at this region  is detached by coagulation.   The problem are arterial  feeders coming directly through   the bone as they cannot be  coagulated by bipolar forceps.   They are best handled by  drilling with a fine diamond   drill, so-called hot drilling,  which coagulates these feeders   by heating the bone locally.   We prefer not to drill the  whole area of the hyperostosis   on the anterior skull base,  but only the region where   the main feeders are.    
SPEAKER: Based on our experience,  this reduces the risk of CSF   leak due to accidental entering  into the ethmoidal sinuses.   At the same time, it does not  seem to dramatically increase   the risk of tumor recurrence.   Once the main feeders  are taken care of,   we move more anteriorly  towards the proximal attachment   of the falx as highlighted  by the green cone.   The inferior part of the  falx is coagulated and cut   with microscissors.    
SPEAKER: Care is taken not to enter into  the superior sagittal sinus.   This move allows us to  reach the most anterior   area of the contralateral  anterior cranial   fossa and the tumor attachment  as shown by the red cone.   We continue by detaching  the contralateral part   of meningioma from  the skull base.   Our experience is that in  the giant olfactory groove   meningiomas, the olfactory  nerves are already   so damaged and  thinned that there   is no real chance of leaving  them intact during the tumor   removal.    
SPEAKER: The devascularization along  the anterior skull base   is progressively continued.   The dissection is next oriented  towards the most posterior   part of the tumor attachment and  the contralateral optic nerve.   Keeping both hands in the  operative field while rotating   and moving the exoscope scope  camera remotely by a foot   pedal speeds up the surgery  and gives good control   over the dissection.   The excellent  rotational possibility   of the exoscope camera,  allows to visualize   all the deeper regions  of the anterior skull   base, respecting surgeons  ergonomics even   at the extreme angles.    
SPEAKER: At the same time, the  improved magnification   and 3D visualization  give a better control   over the entire surgical area  and demonstrate the anatomy   also for teaching purpose.    Once the whole tumor  insertion is detached,   we can see also the  contralateral optic nerve.     
SPEAKER: Finally, the tumor is  devascularized also   from the small feeders  coming from the falx   at the anterior superior  region near the midline.   With most of the  tumor feeders gone,   the next main goal  is to start working   on the tumor borderline.   We use water  dissection technique   to expand the natural  plane between the tumor   and the brain, followed by  blunt and sharp dissection   to progressively detach the  tumor from the pial surface.    
SPEAKER: All the arteries on  the tumor surface   must be dealt with  very carefully.   Some of them are  en passant types,   others are just  feeders of the tumor.   We prefer to dissect and save  all the arteries initially.   Only later, if we are very  sure that they are only   feeding the tumor, they  can be coagulated and cut.   Ultrasonic aspirator can  be helpful in debulking   and shrinking of  the superficial part   of the tumor for additional  space along the tumor   borderline.    
SPEAKER:  In a very large  tumor such as this,   the next step is to  progressively debulk the tumor   to reduce its volume and  allow for further dissection   along the borderline.   Since the tumor was  previously devascularized,   it is bleeding very little.    The ultrasonic aspirator can  be helpful in the debulking.    
SPEAKER:  Once the tumor volume has  been sufficiently reduced,   it is possible to continue  with the final dissection   along the tumor borderline.   The last part of the  meningioma is carefully   dissected from the ipsilateral  pericallosal artery.   Later, the more distal  part of the falx   is incised so that the  superior part of the tumor   on the contralateral side  can be reached as well.    
SPEAKER: Finally, the remaining  tumor mass is removed.    After tumor removal,  intraoperative anatomy   can be appreciated.   We can see the  displaced ACom complex   and the pericallosal  arteries, the ipsilateral   and contralateral optic nerves,  and the contralateral carotid   artery.   Careful hemostasis is performed  throughout the whole resection   cavity.    
SPEAKER:  The closure is done  in multilayer fashion.   There were no new  postoperative deficits.   At 3 months' follow-up,  the visual acuity as well as   the visual fields had  shown improvement.   The gross-total resection  was confirmed with MRI   at 3 months.