Neuroendoscopic Anatomy And Surgery Of Sellar Area

PART 1:STUDY OF NEUROENDOSCOPIC APPLIED ANATOMY OFSELLARAREABackground: The sellar area is one of important area where the diseases origin from, The common neuroendoscopies of the sellar area include arterial aneunysm clipping, pituitary adenoma, craniopharyngioma, epidermoid cyst and other tumor removal etc. To know the histology of cranial nerves and vessels and the anatomical relationship between cranial nerves and vessels under neuroendoscope is the diagnosis and treatment bases of the sellar area lesions by neuroendoscope. It is necessary to master neuroendoscopic anatomy of the sellar area for neuroendoscopic neurosurgery.Objective: To probe into the feasibility of observation of vascular and neuval structures in the sellar area, which provides locally applied anatomy for surgical treatment of the sellar area lesions under neuroendoscope.Methods: Bilateral sellar areas were observed anatomically in five cases of adult cadaver heads under microscope assisted by neuroendoscope. Three kinds of keyhole approach(supraorbital, pterional and glabella keyhole approach) to the sellar area were performed, and advantages and disadvantages of them were evaluated respectively.Results: ①The important structures of sellar area(include optic nerve, optic chiasma, pituitary stalk, oculomotor nerve, Willis circle and minute perforators, etc) were observed clearly, especially the ventral brain stem and basilar artery and its branches. ②Frontal sinuses of 6 sides in 10 sides of 5 cadveic heads were destroyed via the supraorbital keyhole approach. The frontal lobes were retracted and the arachnoid membranes covering the vessels and nerves of sellar area were separated and removed so as to observe ipsilateral 1CA and its branches, oculomotor nerve,bilateral optic nerves, optic chiasm, pituitary stalk and contralateral ICA; when probe into the interspace between ICA and optic nerve, the endoscope will be obstructed by the branches of PcoA; From lateral of ICA to parasellar and posterior sellar, the operation will be performed not so facilitately as trans pterion approach limited by the size of burr hole; By retracting the (generally not need ressecting) gyrus rectus, ACA and AcoA can be observed. ?Trans pterional approach ICA, PcoA and AcliA can be observed more clearly from side, and the originating point of PcoA can be observed more directly, the perforators of PcoA are generally loacated at the medial wall, and there lack perforators in the interspace between ICA and tentorium. Posterior cerebral artery, supracerebellar artery and oculomotor nerve between them can be observed by separating Liliequist membrane, and ventral-lateral brain stem can be observed too; To midline, bilateral optic nerve, optic chiasm, pituitary stalk and their feeding artery can be observed. ACA and AcoA can be observed by retracting(often need ressecting) gyrus rectus. ?Bilateral frontal sinuses and ethmoid sinuses of 5 caderveric heads were destroyed via glabella keyhole approach(GA). The arachnoid membranes covering sagittal fissure cyst and terminal lamina cyst were separated, bilateral optic nerves and optic chiasm can be observed, and bilateral anterior cerebral artery and anterior communicating artery superio-posterior optic chiasm can be observed directely, and the Internal carotid artery(ICA) and its fork segment, posterior communicating artery(PcoA) and anterior arachnoid artery(AchA) and their perforators were observed by separating the inter-space between ICA and optic nerve, other midline structures, such as pituitary stalk and its feeding artery, subthalamus, bisilar artery and ventral brain stem can be observed via beneath of optic chiasm.Conclusion: (D The important structures(such as nerves and vessels, ect) of the sellar area and the ventral brain stem.can be observed by endoscope via different keyhole approach, and displaying minute structures, especially slim artery, is its great advantage. ?Trans supraorbital keyhole approach, structures in midline, ipsilateral and partly contralateral site can be observed much easily, the disturbance to sylvian vessels is more mild compared with pterion approach, and its incision is moreconcealed compared with GA, so will be accepted more easily, and it is a much better approach to deal with both parrasellar and midline lesions, but it will not be the first selection to treat PcoA aneurysm and lesions developed far laterally and posteriorly; The PcoA can be observed more diretly via pterion approach, operation to parasellar and posterior sellar can be performed more easily, so it is the best approach to treat PcoA aneurysm and lesions developed ipsilateraly and posteriorly, but not conveniently to treat AcoA aneurysm; Midline structures(especially ACA, AcoA) and bilateral parasellar structures can be observed more directly, so lesions located in midline and developed bilaterally not too much can be treated more conviently via GA, but the anterior skull base was destroyed more severely, so the cerebral spinal fluid leakage will occur more likely, and this approach will not be accepted so easily for its exposured incision. ?The advantages and disadvantages of three keyhole approach were compared with each other, so better approach can be selected according to the different locations of sellar area lesions.PART 2: NEUROENDOSCOPE-ASSISTED MICROSURGERY FOR SELLARAREA LESIONSBackground: To attain the best treatment effect with minimal invasion is the aim that every neurosurgeon seeks after, which is also the way and trend of international neurosurgical development now. In 1986, Giffith formally put forward to the concept of endoneurosurgery after summarizing the experience of contribution of endoscope in neurosurgery. After then, a new branch of neurosurgery was recognized. The establishment of endoneurosurgery is based on as follows: (1) getting to the intracranial deep structures for diagnosis and treatment through narrow channel; (2) intraoperative procedure under the direct sight avoids blind operation of stereotacty, which decreases the damage to the surrounding structures. (3) the minimal invasion makes patient recovery sooner and hospital days shorter, which accords with the demand of social development today. (4) it makes up the disadvantages of the microsurgery as an adjunct to surgical microscope. (5) the routine microsurgical procedure is guided by the images of tele-neuroendoscope. the neuroendoscopy is also described as the "keyhole approach". The assumption is not that "smaller is better," but that "smaller is safer." In 1995, Gerszten, et al pointed out that the minimally invasive surgery must satisfy five distinct criteria: (1) the technique must be less invasive than currently used techniques, while maintaining safety. (2) the efficacy of the technique should be similar to or better than that of standard techniques. (3) the technique should lead to a shorter recovery time for the patient, both in terms of the length of hospital stay and in the time required to resume daily tasks. (4) the technique must be more cost-effective. (5) the technique must be technically feasible for the majority of surgeons, both in terms of the level of surgical skill required and with regard to the availability of affordable new equipment. In 1998, Hopf classified neuroendoscopy into three types in the basis of the application of neuroendoscope and operative route: (1) endoscopic neurosurgery: neuroendoscope used single, that is the operation through endoscopic passage. (2) endoscope-assisted microneurosurgery: the endoscope is used together with microscope, which is adjunctive to microscope. (3) the endoscope-controlled microneurosurgery: the microsurgical procedure isperformed with the routine microneurosurgical appliances under the guide of the images of endoscope. In 1977, Apuzzo firstly used the neuroendoscope to assist illumination and inspection while craniotomy and microsurgery, which could make up each other the disadvantages and increase the diagnosis and treatment effects. Now, the development of endoneurosurgery has been changed with each passing day. The operative directions of neuroendoscopy have been extended from intraventricuiar to intraparenchymal diseases, from cystic to solid lesions, from intracranial to intraspinal. The diagnosis and treatment fields of the neuroendoscope have been extended, which has exerted well the advantage of minima] invasion of neuroendoscope. The endoneurosurgery as an important branch of minimally invasive neurosurgery has attracted many domestic and abroad neurosurgical scholars, which is considered as a very promising technique. In 1994, Prof. Guthrie claimed that tele-endoscope—the neurosurgery in the twenty-first century.In the choice of clinical application of neuroendoscopic technique, Hopf considered the single neuroendoscopy should be choosed firstly to treat the intraventricuiar and intrasellar cystic lesions. However, the endoscope-assisted microneurosurgery or endoscope-controlled microneurosurgery was superior to single endoscopic neurosurgery for the treatment of posterior fossa lesions. The neuroendoscopic technique has developed with quite great in the fields of the surgical treatment of hydrocephalus and syringomyelia, removal of intracranial cystic lesions, evacuation of intracranial hematoma, resection small intraventricuiar and intraparenchymal lesions, and stereotactic biopsy. Recently, neuroendoscope-assisted microsurgery used in clipping cranial aneurysm and resection of pituitary adenoma was reported in domestic and overseas literature, But the application of neuroendoscopic technique in the treatment of other sellar area lesions was reported fewer.Objective: To study the utility and advantages of the neuroendoscope-assisted microsurgery for sellar area lesions.Methods: neuroendoscope-assisted microsurgery was performed on 30 patients with sellar area lesions. Of all, 13 patients with cranial aneunysm(include 8 PcoAaneurysms, 5 AcoA aneurysms), 6 with giant pituitary adenoma, 3 with craniopharyngioma, 4 with cholesterotomas in sellar and parasellar area, 2 with tuberculum sellae meningiomas, 1 with cyst in sphenoidal sinus, 1 with arachnoid cyst in sellar area. A 0-or30-degree rigid neuroendoscope was introduced into the sellar area before intracranial procedure. Neurovascular integrity as well as the relationship between tumor and surrounding structures was evaluated firstly. At the end of microneurosurgery, neuroendoscope was introduced again so as to verify the optimal clipping position and the total dissection of tumor. If the clipping position is not optimal, readjustment of clipping was performed under microscope or assisted by endoscope; If the residual tumor was found, neuroendoscope-assisted tumor ressection was performed.Results: All patients experienced resolution or significant improvement of their preoperative symptoms and signs, only 2 transient diabetes insipidus were found, no severe postoperative complications and mortality after the neuroendoscope-assisted microsurgery. 13 aneurysms were gained satisfactory clipping, 6 giant pituitary adenoma were resected totally; of 3 craniopharyngiomas, 2 were resected totally and 1 subtotally; No aseptic meningitis occurred because of total resection of tumor in 4 cholesterotomas. 2 tuberculum sellae meningiomas were resected completely, 2 patients with sphenoidal sinus cyst or sellar area arachnoid cyst achieved good recovery . No complications directly related to endoscopy were found.Conclusion: The neuroendoscope-assisted microsurgery for the sellar area lesions is practicable and helpful to increase the microsurgical treatment effect and decrease the operative risk and reduce the complication.