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The treatment of hydrocephalus nowadays is still a challenge for neurosurgery. Neuroendoscopy is a valuable alternative of the CSF shunts in hydrocephalus management. Because of the complicated and always changeable pathophysiology of hydrocephalus, the history of the endoscopic treatment of hydrocephalus is also a history of severe frustrations, great expectations, and significant achievements. The historical milestones and state of the art of neuroendoscopic treatment of hydrocephalus are reviewed for each of its surgical techniques: choroid plexus coagulation, third ventriculostomy, aqueductoplasty, septostomy, foraminal plasty of the foramen of Monro, and foraminal plasty of the foramen of Magendie. The future trends of neuroendoscopic treatment of hydrocephalus such as robotics, image-guided neuroendoscopic surgical techniques, treatment "in utero", application of stem cell therapy, implementation of new technological solutions, and so on are discussed in the light of the approaching end of the century of neuroendoscopy.

Object: To evaluate the efficacy and safety using fibrin glue and absorbable hemostats for packing the endoscopic tract in a pediatric population in the prevention of subdural fluid collections after endoscopic third ventriculostomy., Materials and Methods: Twenty-one endoscopic third ventriculostomies were performed in 20 hydrocephalic children with a mean age of 22 months over a 4-year period using uniformly this technique. Six children, with age ranged 6 days to 22 months (mean 9 months), had severe ventriculomegaly with thin brain mantle less than 10 mm. There was no mortality and no permanent morbidity related to the endoscopic procedure. One child developed an asymptomatic collection, which could be managed conservatively and was most likely attributed to the young age of the child and the assumed poor cerebrospinal fluid absorption ability. Lost compliance of the brain parenchyma may play an additional role, which was not related to the thickness of the brain mantle. No adverse effects regarding the material used for sealing were observed over a mean follow-up of 23 months., Conclusions: Subdural fluid collections could be prevented in 20 out of 21 procedures by using this technique regardless of the thickness of the brain mantle, the application of mixture of fibrin glue and hemostatic agents seems to be safe, and we consider this technique effective in reducing the risk of this potential complication.

Objective: Most of the endoscopes used for endonasal transsphenoidal surgery use 4-mm diameter lenses. The applicability of a newly developed neuroendoscope with a lens diameter of only 2 mm was tested in endonasal transsphenoidal pituitary surgery., Methods: The newly developed rigid-rod neuroendoscope with a 2-mm lens and an endoscope with a 4-mm lens were coupled with a navigation system and used for this comparative study. Comparison between the views obtained with these two devices was performed in a model and in formalin-fixed cadaver heads. A pure endonasal approach was used to reach and explore the sellar and parasellar regions. The navigation system was used to locate the same position in both lenses for image comparison., Results: The sellar and parasellar regions could be reached and explored using the new endoscope with the 2-mm lens and an oval-shaped irrigation and suction channel. The visual field appeared to be reduced compared with that of the 4-mm lens. However, this reduction was compensated by greater mobility and easier introduction and maneuvering of the instruments at the sellar level. Reduced image size and brightness were also found using the 2-mm lens compared with the 4-mm lens. These differences could be overcome by increasing the amount of light and enlarging the image but with subsequent reduction in image resolution., Conclusion: The small diameter of this neuroendoscope resulted in good maneuverability and maintained a fine quality of vision. Children and patients with small nostrils are good candidates for the use of such a device.

The therapeutic modalities for pineal region tumors in Western countries differ from those in far-eastern countries, that is, Japan and Korea, mainly because of the different patient populations. The majority of pineal region tumors in Japan and Korea are radio sensitive and/or chemosensitive, and adjuvant therapy rather than extensive surgery plays the main part in the treatment of these tumors. The authors have applied minimally-invasive preferential management in pineal region tumors in last 8 years. For the therapeutic regimen, if the tumor markers alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) were not detected in serum and there was significant ventricular dilation visualized on neuroimages, neuroendoscopic surgery was first applied for tumor debulking with tissue diagnosis and gross morphological analysis of the tumor and the intraventricular structures, followed by third-ventriculostomy. In the results, our minimally-invasive preferential regimen clarified the precise indication for neuroendoscopic procedures, and the majority of our patients with dilated ventricles and no evidence of tumor markers were treated satisfactorily with effective neuroendoscopic procedures as the initial procedure. Then avoided unnecessary craniotomy and radiotherapy and promised excellent therapeutic outcomes. Neuroendoscopic procedures have a great advantage in the management of chemo- or radiosensitive tumors, such as germinoma, pineoblastoma, or primitive neuroectodermal tumor. The neuroendoscopic anatomy including the lateral and third ventricles with a pineal region tumor with or without tumor dissemination was described in detail, together with the neuroendoscopic surgical technique.

Object: This prospective study is based on a consecutive series of 20 patients with pineal region tumors who underwent minimally invasive preferential management. The purpose of this report is to discuss the role of neuroendoscopic procedures in the management of pineal region tumors., Methods: If the tumor markers alpha-fetoprotein and human chorionic gonadotropin were not detected in serum and there was significant ventricular dilation visualized on neuroimages, neuroendoscopic surgery was first applied for tumor debulking with tissue diagnosis and gross morphological analysis of the tumor and the intraventricular structures, followed by third ventriculostomy. Subsequent procedures were determined on the basis of verified individual tumors. For treatment of germinomas and pineoblastomas, if no tumor dissemination was confirmed by pre-, intra-, or postoperative findings, stereotactic radiotherapy or radiosurgery was performed after one course of chemotherapy with the ICE regimen (isofomid, cisplatin, and etoposide) and followed by two additional courses of chemotherapy. For treatment of malignant germ cell tumors, after extensive surgery, adjuvant chemotherapy with the ICE regimen was performed in three courses in all cases. Then radiotherapy was started using various methods, depending on the evidence of tumor dissemination. For treatment of teratomatous and neuroectodermal tumors other than pineoblastomas, extensive surgical removal was performed. As for adjuvant therapy, if the tumor was a low-grade glioma or if the patient was younger than 5 years of age, postoperative treatment did not include radiotherapy. If the tumor was a malignant teratoma or high-grade glioma, conventional focal radiotherapy was performed, followed by chemotherapy with ICE for 1 year. All but two treated patients had ventriculomegaly. Neuroendoscopic procedures were performed in six of 15 treated patients. Neuroendoscopic biopsy with tumor debulking offered enough material for tissue diagnosis, including immunohistochemical analysis and, in one case, revealed evidence of tumor dissemination undetectable on neuroimaging. With one exception, no shunt was required in any patient undergoing endoscopic third ventriculostomy. Stereotactic radiotherapy was performed in indicated cases. Favorable therapeutic outcomes were obtained in all cases of germinoma and pineoblastoma, with follow-up periods ranging from 24 months to 6.5 years., Conclusions: Our minimally invasive preferential regimen clarified the precise indication for neuroendoscopic procedures, and the majority of our patients with dilated ventricles and no evidence of tumor markers were treated satisfactorily with effective neuroendoscopic procedures as the initial procedure, avoiding unnecessary craniotomy and radiotherapy and promising excellent therapeutic outcomes. The treatment for malignant pineal region tumors remains a subject for further study.

The clinical application and future prospect of neuroendoscopic surgery are described. In the historical trend, it is emphasized that the neuroendoscopic surgery has become one of the major or leading procedures in "minimally-invasive approaches" to the intracranial lesions. The presently-available instrument include procedures using an endoscope of three different types: rigid-rod, steerable/flexible-fiber-rod and semi-rigid-rod. To use a rigid-rod or fiber-rod scope, it is available to apply forceps, laser, a microballoon and other fine instruments. The indication for neuroendoscopic surgery has been expanded to almost all neurosurgical procedures, as "endoscope-assisted" procedures are applied more to micro neurosurgical procedures (endoscope-assisted microsurgery). The realistic indication for "pure neuroendoscopic surgery" includes reconstruction of cerebrospinal fluid (CSF) pathway such as third ventriculostomy, septostomy, foramen reconstruction, fenestration of septation; removal or biopsy of tumor/cystic lesion, mainly in the intraventricular regions; and removal of hematoma involving the cerebral parenchyma (intracerebral hematoma), ventricles/(intraventricular hematoma) or subdural space (subdural hematoma). The intraparenchymal or deep-seated intracisternal lesions can be the realistic indication for "pure neuroendoscopic surgery" when the instrument are further developed in future. Neuroendoscopic surgery will play a promising and major role in the "minimally-invasive neurological procedure" in the 21st century.