PMC9062963_01
T2-weighted MRI of the head (axial and sagittal views). (a) Before the first surgery, (b) immediately after the first surgery, (c) at the time of recurrence, and (d) 8 months after the second surgery.
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F1
Magnetic resonance imaging (MRI) of the head showed a huge arachnoid cyst extending from the suprasellar region to the anterior skull base and middle cranial fossa bilaterally [Figure 1], and hence, the child was admitted to the hospital for surgical treatment at the age of 9 months.
Head circumference curve. (a) From birth to 12 months. (b) From 12 months.
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F2
At the time of admission, his head circumference was 50 cm [Figure 2], and he had left internal strabismus.
Intraoperative endoscopic findings during the first surgery. (a) The cyst wall was seen through the foramen of Monro. (b) Cauterization and perforation of the cyst wall was performed using a monopolar electrode (RAF electrode, Aims Co., Japan). (c) A balloon catheter was used to expand the stoma. (d) Fenestration between the cyst and the prepontine cistern.
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F3
A flexible endoscope (Olympus VEF-V) was inserted through the right anterior horn of the lateral ventricle, and the cyst wall was seen through the foramen of Monro [Figure 3a]. The cyst wall was perforated and dilated with a balloon catheter followed by coagulation and reduction of the cyst wall with an Elliquence Surgi-Max radiofrequency generator (Elliquence LLC, Baldwin, NY, USA) and RAF electrodes (Aims Co, Osaka, Japan) [Figure 3b]. The cyst wall was perforated and expanded with a Phycon expander balloon catheter (Fuji Systems Co., Japan) [Figure 3c], and a stoma was established between the cyst and the prepontine cistern [Figure 3d].
Intraoperative endoscopic findings during the second surgery. (a) Obstructed cyst wall. (b: Cauterization and perforation of the cyst wall. (c) Multiple perforations were performed. (d and e) The cyst wall was grasped by biopsy forceps and the hole was enlarged. (f) Schema of cyst wall fenestration enlargement. (g) Reocclusion of the space between the cyst and the prepontine cistern. (h) Enlargement of the stoma to the prepontine cistern using a balloon catheter.
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F4
Monro and the previous stoma was seen to be occluded [Figure 4a]. Multiple holes were created in the cyst wall with an RAF electrode [Figures 4b and c] and the holes were enlarged by grasping and nibbling the cyst wall with biopsy forceps [Figures 4d-f]. When the endoscope was advanced inside the cyst, the previous stoma to the prepontine cistern was also found to be closed [Figure 4g]. Hence, two mechanical fenestrations without cauterization were made in this area, and each perforation was expanded with a Phycon expander balloon catheter to form a single large hole [Figure 4h].