Neuroendoscopic techniques have been introduced for 100 years, but their real rapid development has only 20 years of history. Especially in the last 10 years, with the continuous progress of technology, equipment and instruments, neuroendoscopic techniques have become an important branch of minimally invasive neurosurgical techniques, playing an increasingly important role in the treatment of many common neurosurgical diseases.
At present, the scope of application of neuroendoscopic techniques mainly includes.
1, obstructive hydrocephalus
The cause of hydrocephalus is complex, so it is difficult to treat. Although ventriculo-abdominal shunt is widely used in clinical practice with satisfactory results, its complications cannot be ignored. With the development of neuroendoscopic technology, neuroendoscopic third ventriculostomy (ETV) has become the main method for the treatment of obstructive hydrocephalus. This technique is closer to the physiological state of cerebrospinal fluid circulation and avoids the implantation of shunts and their associated complications. Other procedures that apply neuroendoscopy in the treatment of hydrocephalus include catheteroplasty, hyaline septal fistula, and choroid plexus cautery. Ventriculo-abdominal shunts can also be supplemented with endoscopic placement of shunts under direct vision. In case of shunt dysfunction after ventriculo-abdominal shunt, the shunt can be adjusted or removed with the help of neuroendoscopy, which reduces the possibility of intraventricular hemorrhage.
2. Intracranial cystic lesions
2.1 Arachnoid cysts.
Symptomatic or progressive arachnoid cysts require surgical treatment, and commonly used surgical methods include cyst-abdominal shunt, open microsurgery, and endoscopic surgery. Currently, it is advocated to perform “partial cyst wall resection + cyst-pool fistula” under direct neuroendoscopic view, using small incisions and small bone flaps, and applying neuroendoscopic techniques to first perform a major cyst wall resection and then a cyst wall fistula to allow the cyst cavity to communicate with the brain pool or subarachnoid space, thereby reducing or eliminating the cyst cavity and relieving the compression of the cyst on the surrounding structures. Compared with open microsurgery, endoscopic surgery can be done through one bone hole, with short operation time and little trauma; compared with cyst-abdominal shunt, the efficacy is similar, but the possible complications of shunt surgery such as infection, permanent implantation of foreign body, and blockage of shunt can be avoided.
2.2 Suprasellar pool cyst:
Also known as third ventricular cyst, suprasellar arachnoid cyst, or suprasellar-anterior arachnoid cyst, originates from the anterior pontine pool and progresses upward, which can lead to visual impairment, abnormal endocrine function, increased intracranial pressure, and even hydrocephalus. Neuroendoscopic surgery is currently the first choice for the treatment of suprasellar pool cysts, i.e., cyst-ventriculostomy or ventriculo-cyst-ventriculostomy under direct neuroendoscopic view, which has the advantages of minimally invasive, precise efficacy, few complications and fast postoperative recovery compared with other treatment methods.
2.3. Intracerebroventricular cysts.
Intracerebroventricular cysts can be divided into choroid plexus cysts, ventricular meningeal cysts and arachnoid cysts according to their tissue origin. Intracerebroventricular cysts tend to cause blockage of cerebrospinal fluid circulation pathways and form obstructive hydrocephalus. At present, endoscopic surgery is mostly used to remove part of the cyst wall, so that the cyst can fully communicate with the ventricles and restore or reconstruct the cerebrospinal fluid circulation to resolve obstructive hydrocephalus.
2.4, hyaline septal cyst.
A hyaline septal cyst can cause hydrocephalus by obstructing the interventricular foramen or cause neurological dysfunction by compressing surrounding structures. Symptomatic hyaline diaphragm cysts require surgery, which includes: craniotomy, cyst-abdominal shunt, stereotactic surgery and endoscopic surgery. Endoscopic surgery has now become the mainstay of treatment for hyaline diaphragmatic cysts, in which a neuroendoscopic technique is used to open a window in the lateral wall of the cyst to allow adequate communication between the cyst and the lateral ventricle. Compared with other treatment modalities, endoscopic hyaline septal cyst windowing has the advantages of minimally invasive, direct vision, no need to leave a shunt in place, and fewer complications
3.Tumor
(1) Tumors of the skull base.
Pituitary tumors: Although the technique of microscopic transsphenoidal resection of pituitary tumors is well established, the application of neuroendoscopy has contributed to a certain extent to the improvement of the surgical results of pituitary tumors. Endoscopic surgery eliminates the need for a nasal dilator and allows for maximum protection of the normal nasal structures. The angle of the endoscope and the fisheye effect are utilized to facilitate close visualization of the lesion, increasing the extent of visualization and improving the total resection rate.
With the study of skull base anatomy and the development of endoscopic techniques, the endoscopic expanded transnasal butterfly approach can reveal the skull base area from the posterior wall of the frontal sinus to the atlas, from the midline to the jugular foramen area on both sides and the mandibular joint, and has been used for the resection of anterior and middle skull base and slope tumors (such as chordoma, craniopharyngioma, meningioma, etc.), and the combined application with intraoperative navigation, ultrasound, stereotactic, and open MRI techniques also provide the safety and accuracy.
In addition, as an auxiliary tool, neuroendoscopy is also used for microsurgery of tumors in the pontocerebellar horn region such as auditory neuroma, cholesteatoma, and meningioma. Using the angle-forming and wide-angle feature of neuroendoscopy, blind areas of microscopic light can be explored intraoperatively to detect and remove residual tumors. Neuroendoscopy for cystic hemangioblastoma helps to detect tumor wall nodules.
(2) Intracerebroventricular tumors.
Intracerebroventricular tumors mainly include ventricular meningioma, choroid plexus papilloma, astrocytoma, glial cyst, meningioma, etc. Neuroendoscopy can be used for biopsy and resection of tumors in the lateral ventricles or the third ventricle. Compared with traditional microsurgery techniques, neuroendoscopy has the advantages of wider field of view, closer identification of tumors and important structures, clearer images, less cortical damage, and simultaneous treatment of hydrocephalus, etc. However, it is only suitable for substantial tumors with diameter less than 2 cm and relatively soft texture, and it is better to use microsurgery supplemented by endoscopy for tumors with diameter more than 2 cm or hard texture or rich blood supply.
4.Brain hemorrhage:
For intracerebral hematoma, direct intracavitary illumination at close range using neuroendoscopy requires only a small cortical incision and slight retraction of the brain tissue, which can be passed by endoscopy and bipolar electrocoagulation or suction, reducing the cortical damage caused by retraction as well as cerebral edema. Endoscopic treatment of intraventricular hemorrhage can directly remove the accumulated blood, unblock the cerebrospinal fluid circulation pathway more quickly, and prevent secondary hydrocephalus. For chronic subdural hematoma with segregation, conventional drilling and drainage is often ineffective. The use of flexible microscopic techniques can open the segregation of the hematoma cavity under direct vision and help drain the hematoma completely.
5.Spinal cord and spine diseases
Neuroendoscopic technology has been used for the treatment of spinal cord tethering syndrome, Chiari malformation, spinal cord cavitation, disc herniation and other diseases.
6.Other
Neuroendoscopic techniques are also used for intracerebroventricular cysticercosis, cerebrospinal fluid nasal leakage, ventriculitis, brain abscess, optic nerve canal decompression, microvascular decompression for facial spasm and trigeminal neuralgia, etc.