Neurosurgery has entered the era of “minimally invasive”, and neuroendoscopy (hereinafter referred to as endoscopy) meets the requirements of “minimally invasive”. Compared with traditional surgery, endoscopic surgery has the advantages of clear vision, precise operation, slight injury, few complications, rapid recovery, precise efficacy, short hospital stay, and low medical cost; as long as the surgical indications and operation techniques are accurately and skillfully mastered, there are few cases of disability or death caused by using this technique. With the continuous improvement and perfection of endoscopy and its instruments, and with the accumulation of experience in endoscopic surgery, the application of endoscopic technology will become more and more extensive, and the indications will be widened. Therefore, in recent years, endoscopic surgery has been rapidly promoted and applied in the field of neurosurgery.
1. Indications for neuroendoscopy
At present, the indications for endoscopic surgery are: subdural hematoma, intraventricular hemorrhage, cerebral hemangioma, pituitary tumor, arachnoid cyst, cerebrospinal fluid leak, cholesteatoma, hydrocephalus, trigeminal neuralgia, facial spasm, brain abscess, skull base chordoma and so on. The treatment of each of these diseases is discussed below.
2. Current status of endoscopic treatment for their main indications
2.1 Subdural hematoma
The traditional simple puncture and drainage for chronic subdural hematoma has the shortcomings of large trauma, incomplete hematoma removal and easy infection. The endoscopic incision is small and the hematoma can be removed under direct vision, which avoids the disadvantages of inaccurate puncture and incomplete removal of hematoma and the large trauma of craniotomy, and the first time endoscopic hematoma removal rate is higher, and the drainage time is shorter or no drainage is needed, which reduces the infection rate. Moreover, endoscopy is less invasive, and patients have a shorter hospital stay and faster recovery. Endoscopy has significantly fewer complications than conventional drainage, suggesting that endoscopic treatment is particularly useful for patients with severe disease and advanced age.
2.2 Ventricular hemorrhage
Ventricular hemorrhage is one of the best indications for endoscopic treatment, and the ventricles provide the necessary space for endoscopic manipulation. Endoscopic removal of ventricular hematoma is significantly less invasive than traditional debridement or small bone window cranial hematoma removal, and can be performed under direct vision, thus accurately removing the hematoma, but the principle of reducing intracranial pressure, not reluctant to completely remove the hematoma, the shortcoming is that the ability of endoscopy to stop hemorrhage is limited, and if hemostasis is difficult, endoscopy may fail and be forced to change to cranial hematoma removal, so preoperative should be done at the same time Therefore, preoperative preparation for cranial hematoma removal should be done.
2.3 Cerebral hemangioma
The diagnosis of cerebral cavernous hemangioma is difficult, but the advent of endoscopy has provided a new way to diagnose it correctly. It is also beneficial for its treatment. Because the endoscope has a good light source and can magnify images, it enables the operator to better understand whether the aneurysm is completely clamped and to judge whether the clamp is securely positioned and whether important penetrating branches and nerves are affected during aneurysm microsurgery than during microsurgery alone, which is of great value in improving the outcome of aneurysm surgery. Endoscopic-assisted microsurgery for aneurysms helps to improve the success rate of clamped aneurysms, reduces missed diagnoses, and does not cause additional surgical trauma.
2.4 Pituitary aneurysm
Traditional microscopic pituitary tumor resection is more invasive. In contrast, endoscopic treatment of pituitary tumors minimizes surgical trauma because the endoscope utilizes the physiological channel of the nasal cavity, eliminating the need to incise the sublabial or intranasal mucosa and the need for pterygoid sinus retractors, and even eliminating the need for postoperative oil gauze. Moreover, endoscopy allows direct visualization of the lesion, which makes it easy to detect residual tumor and remove it completely. The total tumor resection rate of endoscopy is higher than that of traditional surgical treatment and less traumatic, so it is more promising in clinical application.
2.5 Arachnoid cysts
Endoscopic treatment of arachnoid cysts is less invasive than traditional craniotomy, with fewer complications, faster recovery and higher surgical safety.
2.6 Cerebrospinal fluid leak
Cerebrospinal fluid nasal leak is formed when the dura mater and supporting structures at the base of the skull break down, allowing the subarachnoid space to communicate with the nasal cavity and cerebrospinal fluid to flow out through the nasal cavity, commonly after trauma, tumors, sinus disorders and surgery. Traditionally, it is treated conservatively, but is prone to infection and has a long recovery period. Endoscopic repair of cerebrospinal fluid leak through the nasal cavity has the advantages of being minimally invasive, operating under direct vision, accurate intraoperative fistula judgment, no facial scarring from open incision, and less prone to infection, and has become the first choice for treatment of cerebrospinal fluid nasal leak .
2.7 Cerebral cholesteatoma
Cholesteatoma of the skull base has the characteristic of growing along the subarachnoid space to the adjacent parts, thus forming a huge irregular occupying lesion. Because of the irregularity of the lesion, traditional craniotomy is very traumatic to normal brain tissue and difficult to remove the tumor completely; microsurgery alone often makes it difficult to remove the tumor completely because of the “dead space” under the microscope.
Endoscopy can help to find the remaining tumor in the “dead corner” of the microscope, improve the total resection rate and reduce tumor recurrence. Because the endoscope can directly reach the deep intracranial area, with its good light source, the surgeon can clearly observe the structures around the lesion and effectively avoid damaging the important cerebral nerves and blood vessels around the deep lesion, thus reducing the surgical complications.
2.8 Hydrocephalus
Traditional treatment of hydrocephalus often uses ventriculoperitoneal shunts, but there are more complications such as blockage of shunts and infection, which can easily cause treatment failure. Endoscopic trans-third ventriculostomy for hydrocephalus is easy to perform, and the cerebrospinal fluid circulation is more physiological than that of ventriculoperitoneal shunt, and there is no need to place drainage tubes, which eliminates the complications of shunt blockage, infection and shunt exposure.
2.9 Trigeminal neuralgia
Endoscopic minimally invasive vascular decompression and release commissurotomy is a radical method for the causal treatment of trigeminal neuralgia, which can completely preserve the nerve and vascular function.
2.10 Facial muscle spasm
Endoscopy can show and observe the lesion site more clearly than microscope, which facilitates the operator to observe the vascular compression from multiple angles, makes it easy to identify the responsible vessel, evaluate the decompression of the nerve root and the size and placement of the pad, thus improving the surgical effect and reducing postoperative complications.
2.11 Brain abscess
Non-surgical treatment is ineffective for brain abscesses of large diameter (≥4 cm), and surgery is the main treatment for such brain abscesses, but traditional craniotomy is more invasive. Endoscopic treatment causes less damage to the cerebral cortical layer and normal brain tissue around the abscess, allows direct visualization of the abscess cavity and flushing of the pus, and also avoids cerebral hemorrhage caused by puncture under blind operation.
In endoscopic treatment, for thick-walled abscess, microscissors can be used to cut open the abscess wall for pus attraction and drainage, so as to thoroughly clean up the lesion; for multi-room brain abscess, the interval between abscess cavities can be opened under direct view of endoscopy for more effective flushing and drainage, which is more thorough and less traumatic than craniotomy treatment.
2.12 Chordoma of the skull base
Chordoma of the skull base mostly occurs at the butterfly-occipital junction of the skull base, commonly at the midline of the skull base such as the slope and the saddle area. The deep location of this tumor and its characteristics of invasion, destruction of important structures of the skull base and compression of the brain stem pose great challenges for surgical treatment. In addition, the recurrence rate is also high due to incomplete removal of tumor.
The endoscopic treatment of skull base chordoma has sufficient endoscopic light source, clear intraoperative field of view, good exposure of skull base tumor, and can discover the tumor in the “dead corner” of microsurgery, which is conducive to complete removal of tumor and reduce tumor recurrence; moreover, due to the small trauma of surgery, there are few serious postoperative complications, and patients recover quickly and have a short hospital stay.
3.Problems and Prospects
Endoscopic technology is developing rapidly, and its application is becoming more and more popular. With the continuous improvement and innovation of endoscopic instruments and the accumulation of physicians’ experience in endoscopic surgery, the effect of endoscopic surgery is getting better and better, and clinicians also keep exploring the use of endoscopy to treat other diseases. Endoscopy has its unique advantages, but it also has its own shortcomings, such as difficulty in controlling heavy bleeding; difficulty in removing hard lesions such as calcification; more parts of endoscopic instruments, which increases the chance of surgical infection.
In addition, how to combine endoscopic technology, microscopic technology, navigation technology and other modern technologies to complement each other’s strengths and weaknesses, so as to both cure the disease and minimize the trauma to the patient. These issues still need to be explored. “Minimally invasive” is one of the important trends in the development of modern surgery, and endoscopic surgery treatment is in line with this development trend.