The goal of treatment for pineal tumors is to remove the tumor while restoring the CSF routes. Before defining a therapy protocol, several significant factors should be examined . Because a large percentage of the tumors are radiosensitive, surgical excision is not required. Infiltrative tumors can be surgically removed, but only in part. Increased intracranial pressure caused by obstructive hydrocephalus can sometimes appear before the symptoms and signs of localized tissue compression. If the intracranial pressure is regulated by internal CSF drainage without any additional steps to lower the tumor size, individuals with benign slow-growing infiltrating neoplasms may endure a long and largely symptom-free time . Direct excision of tumors (transcallosal transventricular transchoroidal, supracerebellar-infratentorial, or transcomissural technique) and restoration of the CSF pathway can result in a high risk of morbidity, particularly if the foramina of Monro are narrowed . Alternative treatments include CSF shunting, performance imaging-guided biopsies, and radiation. However, such instances may show the highest frequency of CSF shunting problems, namely shunt obstruction, which is likely owing to the high CSF protein level. Image-guided biopsy is a separate operation that carries additional hazards, especially in vascularized tumors in such location of crowded area with vascular and brain stem structures [11, 12]. Endoscopic ventriculostomy has risks that are not comparable to shunting operations [15,16,17,18].
According to a literature study, the long-term success rate of endoscopic ventriculostomies in cases with secondary aqueduct stenosis is greater than 80%. However, because of the possibility of CSF malabsorption via arachnoid villi, this approach has been shown to be ineffective in non-tumoral aqueductal stenosis, particularly in young infants. As a result, individuals with tumoral aqueductal stenosis are treated as a distinct entity, with endoscopic ventriculostomy being the treatment of choice .
Endoscopy not only solves the CSF route obstruction, but it also enables for the determination of the lesions’ histopathological type in a single session .
The biportal endoscopic approach allows for a tumor biopsy and quick restoration of physiological CSF routes. Under direct vision, a tumor biopsy can be conducted. as a result, it aids in the prevention of vascular tumor damage. Bimanual-like manipulations are possible with the biportal technique. Furthermore, it provides for the reasonably precise assessment of anatomic structure sizes and distances .
During ventriculoscopic procedures, anesthesiologists have recorded intraoperative hemodynamic changes. Hemodynamic shifts are common and usually transient. However, if tachycardia, bradycardia, hypertension, hypotension, or arrhythmia is detected, surgeons should cease fluid irrigation, ballooning, and endoscopic advancement. Intraoperative cardiac arrest has been recorded on a few occasions . The biportal technique permits appropriate drainage of the irrigating fluid and easy management of the pressure in the ventricles via the two irrigation channels of the endoscope through one sheath and another separate sheath of the other trajectory; thus, even if one or more outflow channels are obstructed, all of these concerns are theoretically reduced.
Several publications have recommended drilling one “compromised” burr-hole in the middle of the two optimum entry sites . However, there are some drawbacks, such as increased fornix pressure during ETV and the posterior border of the foramen of Monro during endoscopic biopsy. Furthermore, this approach is only appropriate for big tumors that are not too far posterior .
Endoscopic biopsy and third ventriculostomy can be performed with a rigid and flexible endoscope in a single session monoportal method . However, the flexible endoscopic system’s lower optical quality has become a significant restriction, potentially affecting the ability to detect tumor spread . Furthermore, the flexible forceps’ reduced size compared to rigid endoscope forceps may impact the size of the biopsy sample, resulting in inconsistent histology results . Furthermore, maneuvering the flexible ventriculoscope via the foramen of Monro and directing it toward the third ventricle’s massa intermedia can be difficult. Moreover, the tumor should be biopsyed and coagulated without irrigation. More significantly, any bleeding from the biopsy site could result in total vision loss .
Only three cases with pineal region lesions, operated through simultaneous biportal techniques, have been reported in the literature up to our knowledge; however, the surgeon performed a CT-guided endoscopic procedure using an imaging-compatible Cosman-Roberts-Wells stereotactic coordinate frame (Radionics), which may be time consuming and technically demanding in comparison to frameless navigation. In addition, he used two endoscopes at the same time through the two trajectories .
In all our three patients, there was no surgery-related mortality or morbidity. Flow-sensitive MRI revealed patent ventriculostomies in all of the patients. In two patients with germinoma, postoperative irradiation was performed, and in the third patient with pinocytoma, he refused additional surgical procedures and radiotherapy.