Although the occurrence of mass lesions in the lateral ventricle is uncommon, it still presents substantial technique challenges to achieve total resection due to its deep location and the neighboring vital anatomic structures [8]. Lesions in the lateral ventricle are mostly benign, growing slowly and usually not identified until they reach a large size or complicate with obstructive hydrocephalus [2]. At present, the preferred treatment for lateral ventricular tumors is still the surgical resection [9, 10]. Complete tumor resection with preservation of the surrounding nonpathologic parenchyma could confer a favorable prognosis for patients. Thus, a number of factors should be taken into consideration for surgeons while they finally choose an operative corridor for each patient. To achieve the target of best prognosis, the surgical route should meet the following requirements: minimal transgression and retraction of normal brain tissues, maximum angles to achieve effective gross total tumor resection and early exposure of vital anatomic structures. In recent years, with the development of the surgical techniques and the concepts renewal of the minimally invasive surgery, endoport-assisted neuroendoscopic techniques has become a reliable method for the resection of lateral ventricular tumors.
In neuroendoscopic surgery, most surgical procedures are performed via congenital or artificial cavities to provide certain space for endoscope to observe the lesions closely. Endoport is a relatively thick, independent working channel that provides good access for operation techniques without damaging para-channel normal brain tissues [7]. It allows endoscope, attractor and surgical instruments to be inserted freely and facilitates bimanual microsurgical technique under direct endoscopic visualization. Endoport-assisted neuroendoscopic surgery could move the channels from multiple angles with limited brain tissue damage, so as to obtain a larger exposure space [11–13]. Compared with traditional craniotomy, Endoport-assisted nueroendoscopic surgery is more minimally invasive in the protection of normal brain tissues than retractor-assisted surgery.
A total of 16 patients with lateral ventricular tumors were included in the study. All patients underwent endoport-assisted neuroendoscopic resection of the tumors, without the use of microscopy. All surgeries were performed by experienced neurosurgeons with rigorous training in neuroendoscopic techniques and solid microsurgical skills. Our preliminary results postoperatively showed a high rate of tumor resection, a good efficiency of hemostasis and a favorable prognosis of patients by the application of this technique.
Now we summarize the technical points of endoport-assisted neuroendoscopic lateral ventricular tumors resection as follows. Firstly, locate the tumors precisely. Accurate localization of tumors intraoperative was the key for a successful operation. Due to the deep location of lateral ventricles, a slight deviation in the direction of endoport insets will directly influence the exposure of tumors. The application of intraoperative is particularly helpful for the accurate localization of tumors. All patients included in this study underwent head CT and MRI preoperatively to obtain the detailed imaging data and perform the precise intraoperative navigation. Furthermore, it has been reported that the application of endoscopic ultrasonography in real-time intraoperative tumor positioning is more conducive to remove tumors completely and protect neighboring important anatomic structures [14]. Secondly, take great advantage of Endoport’s benefits. In our study, we employed Endoport to provide surgical channel. The entry site of Endoport mainly selected in the non-dominant hemispheres and non-functional regions. The depth of the inserted-Endoport and the presence of bleeding of brain tissues around the channel could be observed through the transparent sidewalls of Endoport. Intermittent irrigation by using physiological saline was employed during surgery to keep surgical field clear. Adjusting the angle of Endoport intraoperatively based on the size and scope of tumor to obtain a comprehensive observation of tumor is conducive to achieve complete tumor removal. It is important for surgeon to operate gently while adjusting Endoport, avoiding contusion or bleeding of brain tissue. Posterior endoscopic blind area has always been one of the disadvantages of neuroendoscopic surgery [12]. The application of Endoport can completely isolate brain tissue outside the channel, effectively reducing intraoperative worries and avoiding accidental injury of brain tissue. Although it has been reported that tumors with hard texture or large size (> 3 cm) were the main limitations of Endoport-assisted neuroendoscopic surgery. With the improvement of endoscopic channels and the updating of surgical instruments such as ultrasonic dissector, larger tumors can also be removed by endoscopic technology [11, 15]. Thirdly, give full play of the advantages of close observation of neuroendoscopy. Because microscope can only magnify the surgical field on a straight line, it just plays limited roles in total resection of lateral ventricular tumors which is at deep position. Compared with microscope, neuroendoscopy combined with angle endoscopy can magnify the surgical field at a wider angle to show the shape of tumors and peri-tumor structure at maximum range. Thus, a higher rate of tumor removal and better protection of brain tissue were achieved under skilled use of this technique. In the group of patients, follow-up results showed that the total tumor resection rate is 80% and the subtotal tumor resection rate is 20%. Because of the wide observation range of neuroendoscopy, the traction of brain tissue is significant lesser than operated under microscopy, which fully reflects the concept of minimally invasive neurosurgery. Fourthly, keep the cerebrospinal fluid (CSF) circulation unobstructed. CSF circulation disturbance was often complicated in patients with lateral ventricular tumors before operation. It is important to keep the patency of interventricular foramen during operation, avoiding blocked by blood clot. If external ventricular drainage is needed, the flow velocity and flow volume should be controlled postoperatively to avoid the occurrence of ventricular walls adhesion or isolated ventricle. Moreover, the release of CSF during operation when endoport entered the ventricle should also maintain slowly to prevent the rapid collapse of brain tissue [16]. If not, it may readily induce intraoperative epidural hematoma, especially in the young people [17]. Fifthly, perfect postoperative management is extremely important. Patients should be more intensively monitored to avoid the occurrence of various postoperative complications like hydrocephalus, limb movement disorder, stress ulcer, intracranial infection, deep vein thrombosis, etc. Once happening, timely detection and early intervention can help minimize the long-term neurological dysfunction. Further standard treatment is also needed for some patients after discharge according to the specific pathological types. In cases of this group, the patient diagnosed with glioblastoma survived 16 months postoperatively and the patient with diffuse astroglioma achieved long-term survival with residual tumor. Since both tumors originated in the thalamus, in order to preserve the function of the structure as much as possible during the operation, they did not meet the standard of complete tumor resection. No other residual or recurrence of tumors were found during the follow-up.
Overall, Endoport-assisted neuroendoscopic techniques have apparent advantages in dealing with lateral ventricular tumors. Endoscopic excision of lateral ventricular tumors affords high tumors total resection rate, less damage, high safety and good prognosis. This technique is worthy to be popularized in clinical practice.