Anatomic Study And Preliminary Clinical Applications Of Extended Endoscopic Endonasal Transsphenoidal Approach To The Suprasellar Region And Third Ventricle

ObjectiveThis study aimed to investigate the anatomic characteristics of extended endoscopic endonasal transsphenoidal approach to the suprasellar region and third ventricle, which include searching respective anatomic landmarks in different steps and finding different routes from the suprasellar region into the third ventricle. To establish an anatomic basis for clinical applications of extended endoscopic endonasal transsphenoidal approach to the suprasellar region and third ventricle.MethodsFour formalin-fixed and one fresh cadaver heads, in which the common carotid artery and vertebral artery were inject with red latex, the internal jugular vein were inject with blue latex, were dissected using an extended endoscopic endonasal transsphenoidal approach to expose the suprasellar region, followed by entering into the third ventricle through infrachiasmatic and suprachasmatic region respectively. The observing was completed with 0-degree lens and 30-degree lens. Anatomic measurements were obtained.Results1. The anatomic landmarks were choanal and sphenoid ostium in the nasal step, optic protuberance, medial and lateral opticocarotid recess, carotid protuberance, sellar floor, tuberculum sellae, planum sphenoidale, clival recess in the sphenoid sinus step, lamina terminalis and tuber cinereum in the intradural step. The numbers of the sphenoid septations ranged from 1 to 4. There were 2 sphenoid septations inserted at the carotid protuberance in 4 cadavers. The distance between the choanal and sphenoid ostium was 12.1±2.3 mm (9.9-15.0 mm) in the left side and 13.3±2.6 mm (9.6-16.8 mm) in the right side; The distance between the bilateral medial opticocarotid recess was 9.5±3.0 mm (5.5-13.8 mm); The distance between the bilateral lateral opticocarotid recess was 14.8±3.7 mm (9.2-19.2 mm); The distance between the carotid protuberance was 16.0±3.1 mm (11.3-18.8 mm)。2. Infrachiasmatic region showed pituitary gland, pituitary stalk, bilateral superior hypophyseal artery, posterior clinoid process, basilar artery, bilateral superior cerebellar artery, bilateral posterior cerebral artery, bilateral posterior communicating artery, perforating arteries, bilateral oculomotor nerve, tuber cinereum and the mamillary body. Suprachiasmatic region showed bilateral anterior cerebral artery, anterior communicating artery, Heubner recurrent artery, lamina terminalis and gyrus rectus.3. After opening the tuber cinereum via the infrachiasmatic region, the roof, posterior wall and floor of the third ventricle were exposed. The third ventricle can also be exposed by opening the lamina terminalis via the suprachiasmatic region. The lamina terminalis approach was better in exposing the floor of the third ventricle, while the tuber cinereum approach was better in exposing the roof. The 30-degree lens supplemented the view of 0-degree lens.Conclusions1. The anatomic landmarks in different steps provide correct anatomic directions and safe operational range, which are need to be recognized and identified.Sphenoid septations often insert at the carotid protuberance. As such, extreme care should be taken when identifying and removing these septations intraoperatively.2. The extended endoscopic endonasal transsphenoidal approach is feasible to expose the suprasellar region and enter into the third ventricle through two corridors, which is a safe route to remove lesions in this areas. ObjectiveTo summarise preliminary experience of resecting tumors in the suprasellar region and third ventricle via an extended endoscopic endonasal transsphenoidal approach with image-guided system in Zhongshan hospital of Fudan University and to investigate the feasibility and efficacy of this approach.MethodsA series of 13 patients with a lesion involving the suprasellar region and third ventricle were treated using an extended endoscopic endonasal transsphenoidal approach with image-guided system. The series included 2 cases of tuberculum sellae meningioma,4 cases of craniopharyngioma, in which 1 case underwent transcranial surgery and gamma knife surgery before and 7 cases of pituitary macroadenoma, in which 3 cases accepted surgery or gamma knife surgery before.ResultsIn tuberculum sellae meningioma group, visual loss was presented in 1 patient, decreased visual acuity was presented in 1 patient. Hypopituitarism was absent. Total removal was achieved in both patients. Visual improvement was achieved in both patients, temporal diabetes insipidus was presented and temporal hormone compensatory substitution was needed in 1 patient. In craniopharyngioma group, visual loss and hypopituitarism was presented in all patients. Surgical results comprised by total removal in 3 patients and subtotal removal in 1 patient who underwent transcranial surgery and gamma knife surgery before. Visual improvement was achieved in 3 patients. One patient achieved visual improvement in the right eye but impairment in the left. Hypopituitarism was not recovered and hormone compensatory substitution was needed in all patients. Temporary diabetes insipidus were presented in all patients. Cerebrospinal fluid leakage was found in 3 patients and intracranial infection was found in 2 patients. In pituitary macroadenoma group, visual loss was present in 7 patients, hypopituitarism was present in 4 patients. Surgical results comprised by total removal in 4 patients, subtotal removal in 2 patients and partial removal in 1 patient. Visual improvement was achieved in all patients. Preoperative hypopituitarism was recovered in 1 patients while 3 patients was not. Hormone compensatory substitution was needed in all patients. Temporary diabetes insipidus were presented in 4 patients. One patient presented with cerebrospinal fluid leakage, intracranial infection, his family gave up treatment and the patient eventually died. Follow-up study was carried out for 1 to 8 months. Intraoperative neuronavigation identified anatomic landmarks and tumor border exactly.ConclusionsThe extended endoscopic endonasal transsphenoidal approach has the advantages of no needing for brain retraction, minimal optic apparatus manipulating, offering direct vision for tumor resection and protecting surrounding neurovascular structures easier. This approach expands the indications of transsphenoidal pituitary surgery, which could be used to remove large pituitary adenomas invading the suprasellar region and third ventricle. As to craniopharyngiomas in the suprasellar region and third ventricle, the extended endoscopic endonasal transsphenoidal approach offers panoramic view of retrochiasmatic and infrachiasmatic region and facilitates dissecting adhesion between the tumor and surrounding structures and protecting pituitary stalk, optic chiasm and superior hypophyseal artery, it also reduces bleeding and makes total tumor removal easier because of handling the origin of the tumor firstly. As to tuberculum sellae meningiomas, the extended endoscopic endonasal transsphenoidal approach resects dural attachments and abnormal bone from the ventral side that ensures Simpson Grade 1 resection. Neuronavigation has an important role in guiding surgical direction, deciding the opening size of skull base and increasing safety of the operations. The extended endoscopic endonasal transsphenoidal approach is a novel, safe, effective and minimally invasive approach for selected tumors involving the suprasellar region and third ventricle.