The application of neuroendoscopy in the midline area of the skull base Due to the special structure of the skull base, there are often some “dead ends” with microscopic observation.
1, anatomy: 1, endoscopic skull base anatomy study: from the crown to the anterior edge of the foramen magnum of the skull base in the midline area is relatively deep in the dorsal side of the brainstem and basilar artery and other structures, the ventral side of the nasal cavity, paranasal sinuses and oral cavity, but also large blood vessels and cranial nerves and other access to the skull, both complex and important.
Wood et al. divided the skull base into midline and lateral parts; Fukuta et al. referred to the frontal sinus, sieve plate, pterygoid plateau, optic chiasm, pituitary fossa, saddleback and slope as “midline region of the skull base”; Ammirati et al. further delineated the boundaries of the Midine compartment from intracranial and extracranial; cavallo et al. called the narrow region from the anterior border of the foramen magnum of the corpus cavernosum, including the ventral craniocervical junction area, Midlin skull base. Neuroendoscopy can play a full role in the midline of the skull base due to its own advantages. Usually, endoscopic surgery via nasopalatine approach can reduce surgical trauma and expand the exposure of the pterygoid saddle, suprasellar and parsellar structures.
2, comparative anatomy: 3, neuroendoscopic surgical landmarks: finding surgical landmarks can better locate the position of the endoscope in the skull. In the ventral part of the cervical junction area, the pharyngeal orifice of the eustachian tube is a sign to confirm the anterior margin of the foramen magnum, and the anterior atlantoaxial node is a sign to determine the anterior arch of the atlas.
Endoscopic treatment of disease types: 1 anterior cranial fossa base: In recent years, with the development of endoscopic surgical techniques, attempts have been made for lesions in the anterior cranial fossa base. (l) optic canal decompression: usually traumatic optic canal fracture, abnormal proliferation of bone fibers, tumors near the optic canal and other diseases resulting in vision loss, optic canal decompression can be selected. takata in 1950 first reported the opening of the septal sinus through the nose, into the pterygoid sinus, in the posterior l two side of the pterygoid sinus to find the optic canal method; Kennerde]] in 1976 to open the maxillary sinus In 1981, an incision was made outside of the nose near the medial aspect to expose the medial orbital bone wall, which was opened and then decompressed; Aurbach et al. proposed that endoscopic decompression could achieve the advantages of less trauma and better results. Endoscopic decompression of the optic nerve canal has been recognized by many scholars at home and abroad. Before endoscopic decompression, we should pay attention to the imaging examinations such as 3D-CT and MRI to clarify the anatomical structure of the septal sinus area and to provide reference for the surgery. Some scholars believe that optic nerve decompression requires opening the optic nerve sheath, but in clinical practice, the safest site to open the optic nerve sheath is at the junction of the superior and medial walls of the sheath to avoid damage to the ophthalmic artery. Endoscopic transsphenoidal optic nerve decompression has the following advantages: no external incision, good cosmetic benefit, decompression, no damage to the olfactory nerve, good intraoperative visualization, low disability rate, short operative time, and fast postoperative recovery. The disadvantage is that the upper and lateral walls of the optic nerve canal cannot be revealed, and the decompression is limited to the inner and lower walls; (2) meningioma: endoscopic surgery through the nasal butterfly approach can reveal the wide area from the coronary to the optic cross groove. With the development of skull base repair techniques, some meningiomas in the saddle nodes, pterygoid plateau and olfactory sulcus can be safely resected endoscopically. They concluded that the angle-forming endoscope could provide a good surgical view of the suprasellar structures in a small space and could play a significant role in the total resection of the tumor by transsphenoidal surgery. Therefore, the application of neuroendoscopic transnasal-expanded pterygoid sinus approach to resect saddle-nodular meningioma has certain advantages over craniotomy and simple microscopic approach. Domestic scholars have started to report on the disease in this region in recent years.
2.Lesions in the saddle area and pterygoid sinus: endoscopic surgery through the nasopterygoid approach can reduce the surgical trauma and expand the exposure of the pterygoid saddle, supra- and para-saddle structures. The more common surgical approaches for transsphenoidal pituitary tumor surgery are: (l) a sublabial nasal septal approach to the pterygoid sinus; (2) a septal sinus approach; (3) a transsphenoidal sinus approach. Among them, the sublabial approach is very traumatic, because the lip-eye junction is rich in blood flow and easy to cause more intraoperative bleeding, and the oral cavity is seriously contaminated, and the patient has lip numbness after surgery, which has been less used. The transseptal sinus approach is often used by otolaryngologists, but it is easy to deviate from the midline during surgery and leaves incisional scars, so it is also less used. In both approaches, neuroendoscopy is often used as an adjunct to microsurgery. Currently, lesions in this area are operated through a single nasal sinus approach, where the neuroendoscope is used as the only means of light and imaging. The surgery is performed under endoscopic control, and compared with traditional microsurgery, its surgical route is short and less traumatic. 3. Slope lesions; the surgical treatment of the rock slope area has been the focus and difficulty of clinical research. Previously, the surgical route through the upper collar (upper collar bone external rotation or disassembly), its trauma, complications, easy to cause the patient’s facial palsy scar. The transnasal endoscopic surgical technique provides a new treatment method for the surgical treatment of tumors in the oblique region of the rock. This approach can reach the oblique area easily and rapidly, and can achieve both microinvasive liJ and complete resection of the tumor. Kassam et al. reported a completely endoscopic transnasal approach for the treatment of recurrent chordoma and cholesteatoma on the slope, with satisfactory resection of the tumor and good patient recovery.
Recently, it has been reported that an endoscopic approach can be used to expose the inferior margin of the slope to the superior margin of the C3 vertebral body to better reveal the microscopic dead space and achieve complete resection of the lesion. Craniocervical junction lesions often cause compression of the cerebral millia and ventral aspect of the superior cervical medulla, and a transoral approach is the most direct way to deal with these compressive lesions. In addition, the transoral approach is operated along the midline, and there are no important anatomical structures on the path, which is less traumatic, less intraoperative bleeding, less disturbance to the nerves and blood vessels, and does not affect the aesthetics, and the postoperative recovery is fast.