Name:
10.3171/2023.10.FOCVID23158
Description:
10.3171/2023.10.FOCVID23158
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/b5b7088c-42bc-42ec-98f3-67c4d8a2cb93/videoscrubberimages/Scrubber_209.jpg
Duration:
T00H08M48S
Embed URL:
https://stream.cadmore.media/player/b5b7088c-42bc-42ec-98f3-67c4d8a2cb93
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/b5b7088c-42bc-42ec-98f3-67c4d8a2cb93/7. 23-158.mp4?sv=2019-02-02&sr=c&sig=%2BJv%2B44LlXlYhPdni8sj8YTxBP68LfTixWpl%2B03xjvao%3D&st=2025-02-05T06%3A03%3A49Z&se=2025-02-05T08%3A08%3A49Z&sp=r
Upload Date:
2023-11-30T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING] In this video, we demonstrate exoscope-assisted resection of a recurrent left frontal pilocytic astrocytoma. We present the case of a 23-year-old right-handed male patient who underwent resection of a left frontal lesion in 2014 in another country.
This was followed by a recurrence after 8 years, for which he underwent craniotomy and resection of the lesion at a nearby institution. Initiate histopathology was reported as pilocytic astrocytoma with a repeat review suggestive of oligodendroglioma without loss of heterozygosity of 1p19q and negative for vBRAF600. He underwent a 6-week course of intensity- modulated radiation therapy of 5400 cGy to the lesion.
This was accompanied by 4- week adjuvant temozolomide regimen. This period was marked by significant thrombocytopenia for which his chemotherapy had to be discontinued. For radiological persistence of lesion, he received a tapering course of dexamethasone for the next 4 weeks. Then he noticed worsening of the right-hand function for the past 1 month.
A new MRI showed increase in size of the residual lesion with increased cystic change, edema, and calcified component of the tumor. The T1 postcontrast images demonstrated superficial component with ring enhancement and a nonenhancing core, with deeper core with heterogeneous enhancement along the entire tissue length and breadth. This was suggestive of a superficial cystic or fluid-filled component and a deeper solid lesion.
The functional imaging showed poor activation of speech tasks and good activation of finger tapping tasks located on the surface of the lesion and verb generation tasks also located close to the superficial aspect of the lesion. The perfusion scan showed increased uptake of the tracer within the solid core of the lesion. This was suggestive of a recurrent tumor as opposed to pseudoprogression or radionecrosis.
After discussion in the neuro-oncology tumor board, the patient was considered a candidate for re-resection based on worsening neurological deficit, uncontrolled focal seizures attributable to the lesion. The receipt of recent radiation therapy became a contraindication for radiation in this setting. The setup of the operative room is demonstrated with the surgeon and the assistants' position on the head end of the patient table.
The exoscope is positioned behind the surgeon with the arm angled forward. The exoscope video monitor sits at the foot end of the patient. The neuronavigation station rests at the foot end, and anesthesia table and equipment along the right side of the patient table. This image demonstrates the position of the exoscope behind the surgeon with the arm arching forward and the monitor lying right in front of the view for surgeons and assistants.
A crucial dural incision was made and adhesions of the underlying brain were gently separated from the dura. Neuronavigation was then used to confirm the position of the planned corticectomy, as the lesion was not surfacing. Neurostimulation was then used to confirm the absence of right- sided motor activation within 5- to 10-mm vicinity of the planned corticectomy.
A cortical strip electrode was inserted under the dural leaflet directed posteriorly to map the proximity to the motor cortex. This allowed for ongoing continuous motor evoked potentials during tumor dissection. A noneloquent region of the cortex was identified and, using bipolar forceps, a corticectomy was made.
A cystic structure was gradually encountered in the depth of the corticectomy. The walls of the cyst appeared thick and calcified. A neurostimulation probe was then used to identify the distance of electrical activity from the walls of the cystic structure.
At this point, no motor activity was elicited at 30-mA stimulation. A friable-appearing area was selected at the floor of the cyst wall. And using bipolar forceps, gradual cauterization with decompression of the lesion was started. Debulking of the tissue required use of biopsy forceps with coagulation.
Intermittently, a Rhoton dissector was used to separate the calcified tissue plane from the normal- appearing tissue.
The Sonopet ultrasonic aspirator was used to debulk the lesion in the depth. This was done after confirming the absence of conduction with neurostimulation. As you can see, the tissue was firm and not easily suckable with the Sonopet; hence, debulking required a combined use of ultrasonic aspiration and sharp dissection.
Gradual intratumoral decompression was continued using the Sonopet ultrasonic suction aspirator.
Once adequate debulking was achieved, the neurostimulation probe was used to identify proximity to the corticospinal tracts. This showed that the posterior margin of the lesion was within 5 mm of the tracts and similar proximity was noticed along the anterial, lateral, and the medial margins. This was confirmed with neuronavigation, which showed the position of the probe consistent within the depth of the lesion along all margins.
Haemostasis was secured within the depth of the lesion using cotton balls soaked in peroxide, and Surgicel was used to line the cavity once hemostasis was confirmed. A postoperative CT scan demonstrated subtotal resection of the lesion. Literature has shown that the efficacy of surgical resection under an exoscope is similar to that with a microscope.
The exoscope offers a better interaction between surgeon and assistants and also allows for two surgeons to work in tandem, using four hands, with each surgeon having the same stereoscopic view. Among a series of glioblastoma patients, it was seen that the extent of resection is similar with exoscope and the microscope. And the complication profile also remains the same. The exoscope is proven to reduce surgeon discomfort while providing excellent delineation of tissue with high resolution.
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