Neuroendoscopic Biopsy Research Articles

5-aminolevulinic acid-guided endoscopic biopsy with violet light-emitting diode flashlight in malignant glioma: Technical note.

5-aminolevulinic acid (5-ALA) photodynamic diagnosis (PDD) has enabled better identification of malignant tumor cells and real-time intraoperative guidance. Here, we report a reasonable procedure for 5-ALA-guided endoscopic biopsy with a violet light-emitting diode (LED) flashlight for deep-seated malignant gliomas. A 63-year-old man presented with a headache and left upper homonymous quadrantanopia. Imaging studies showed atypical lesions with non-significant and partial contrast enhancement in the right deep temporo-occipital lobe. An endoscopic biopsy was performed under the guidance of 5-ALA PDD with a violet LED flashlight. The tumor tissues, which were difficult to distinguish from normal brain parenchyma under white light, were positive for 5-ALA fluorescence. The histopathological diagnosis was astrocytoma (the World Health Organization grade 3). The patient underwent adjuvant chemoradiation therapy. Headache and anopia improved, and no recurrence was observed at 12 months follow-up. This technique of neuroendoscopic biopsy guided by 5-ALA PDD fluorescence with a violet LED flashlight may allow a safe and accurate diagnosis of deep-seated malignant gliomas.

Neuroendoscopic Surgery for Pediatric Intraventricular Tumors

Various tumors are found in ventricles and tissues surrounding the ventricles in children, adolescents, and young-adult patients. They cause cerebrospinal fluid pathway obstruction, resulting in hydrocephalus and isolated ventricles. In this paper we describe a neoplasm arising from the lateral and third ventricle. Intraventricular tumors are good candidates for neuroendoscopic surgery. Firstly, minimally invasive and established procedures, neuroendoscopic biopsy with flexible endoscopy or rigid endoscopy, are performed. These endoscopic biopsies can be performed concurrently with other procedures, such as third ventriculostomy or septostomy, to improve cerebrospinal fluid circulation. Neuroendoscopic biopsy for intraventricular tumor is associated with high diagnostic yield and relatively low incidence of morbidity and mortality, compared with open surgery. Endoscopic diagnostic procedure also can be applied in patients without ventricular dilatation, assisted by neuronavigation or echo-guided equipment. Secondly, neuroendoscopic cylinder surgery also makes it possible to remove intraventricular tumors with less damage. The two hands technique with rigid endoscopy helps debulking and hemostasis during tumor removal. Further developments in endoscopic equipment and training systems aimed at enhancing cooperation between the operator and assistant should be expected in the future. Neuroendoscopic resection appears to be a safe and reliable treatment option for patients with intraventricular tumors.

Outcome of endoscopic transcortical intraventricular biopsy of isolated thickened pituitary stalk lesions in children.

The purpose of this study was to investigate the efficacy and safety of endoscopic transcortical intraventricular biopsy in pediatric patients with isolated thickened pituitary stalk lesions. From 1994 to 2018, 16 pediatric patients (8 males and 8 females) underwent endoscopic transcortical intraventricular biopsy at a single institution to establish an accurate pathological diagnosis for appropriate treatment strategies. Preoperatively, the median diameter of the pituitary stalks was 5.31 ± 1.67 mm (range 3.86-9.17 mm). Overall, the diagnostic yield at endoscopic intraventricular biopsy was 93.8%. Histopathological diagnosis included germinoma (n = 10, 62.5%), Langerhans cell histiocytosis (n = 4, 25%), pilocytic astrocytoma (n = 1, 6.3%), and pituicytoma (n = 1, 6.3%). Two patients developed new diabetes insipidus after the procedure, and 3 patients had new postoperative hypothyroidism. There were no postoperative neurological deficits in this series. Neuroendoscopic biopsy via the transcortical intraventricular corridor was shown to be safe and to aid in a reliable histopathological diagnosis in the management of isolated pituitary stalk lesions in pediatric patients. It can be considered a minimally invasive alternative to open biopsy via transcranial or endonasal corridors.

GCT-38. RELAPSE PATTERNS OF INTRACRANIAL GERMINOMAS BEFORE AND AFTER ENDOSCOPIC ERA

PURPOSEWe evaluated the relapse patterns of CNS germinomas before and after introducing neuroendoscopic biopsy in 2000.METHODSWe retrospectively assessed the relapse patterns of 57 patients treated as pure germinoma or germinoma with STGC between 1980 and 2019 at University of Tsukuba, partially containing the patients of the previous report (Takano S et al., World Neurosurg, 2015). Median age was 15 y.o.(7y.o.~38y.o.), and men was 80.7%. Tumor locations were pineal 35, sellar 19, basal ganglia 3, others 11. Group A;1980~1999 was 20, and group B;2000~2019 was 37. From 1980 to 1994, whole brain irradiation(WB) 30.6 Gy plus whole ventricle irradiation(WV) 19.8 Gy. From 1995 to 1999, WV 26~30.6 Gy with Chemotherapy(Chem) or Chem alone. Since 2000, Chem for 3 kurr with WV 24~30.6 Gy, and 6–19.8 Gy as local boost to residual lesion.RESULTSFollow up periods were median 121 M(4.5M~386M; group A), and median 89 M(4 M~231 M; group B). Six patients(30%) recurred in the group A, as ex field 4(1;brain and extramedullary, 1;brain and paranasal sinus, 1;LV & third ventricle, 1;extramedullary), in field 1(LV). Chem only 1(LV & third ventricle). Two patients(5.4%) recurred in the group B, as ex field 2(1;intramedullary, 1;extramedullary). The group A showed CR;18, PR;1, Dead;1(Dissemination), and the group B showed CR;35, PR;1 Dead;1(Encephalopathy).CONCLUSIONWV and Chem prevented extrafield recurrence keeping good quality of life. Neuroendscopy biopsy with ETV did not increase CSF seeding.

Simultaneous single-trajectory endoscopic biopsy and third ventriculostomy in pediatric pineal region tumors.

Pineal region tumors have different pathological tumors and their optimal management remains controversial. Advancements in neuroendoscopy have led to the ability to simultaneously treat the hydrocephalus and obtain a tissue diagnosis. A retrospective review of 34 patients with pineal region tumors in Beijing Tiantan hospital from the year 2016 to 2018 was undertaken. A single bur hole for both procedures was used successfully in all patients. Once pathologic diagnosis is made, the subsequent management of different tumors is dependent on response to therapy, the tumor markers and original pathology. Follow-up period was 4-26months. All 34 cases presented with hydrocephalus and increased intracranial pressure manifestations. Elevated blood tumor markers were found in seven cases. The neuroendoscopic biopsy was diagnostic in 32 samples (94.1%) and nondiagnostic (gliosis) in two patients. 21 cases were germinomas, five cases were tectal astrocytomas, two cases were pineoblastomas, two cases were non-germinomatous germ-cell tumours (NG-GCTs) and 1 case immature teratoma and glioblastoma respectively. During the follow-up period, all germinomas but one case with elevated blood α-fetoprotein received craniotomy with a final diagnosis of NG-GCT received radiotherapy and chemotherapy. Four tectal astocytomas, two pineoblastomas and two NG-GCTs received subsequent open surgery due to progressive development, the pathological data was concordant with the initial endoscopic biopsy sample. An additional VP shunt was inserted in one tectal astrocytoma who have hydrocephalus after craniotomy. Except for 18 cases of transient fever and a case with intratumoral hemorrhage, there was no other significant complications, cognitive disorder and no death. The simultaneous single-trajectory endoscopic technique permits not only to control hydrocephalus but also to obtain histological diagnosis with a low incidence of complication and higher safety. Providing meaningful pathological data, endoscopic biopsies could lead to an appropriate management decision. Especially, it is favored as an early step in the management of patients with marker-negative tumors.

Management of pineal region tumors in a pediatric case series

Pineal region tumors commonly present with non-communicating hydrocephalus. These heterogeneous histological entities require different therapeutic regimens. We evaluated our surgical experience concerning procurance of a histological diagnosis, management of hydrocephalus, and choice of antitumoral treatment. We analyzed the efficacy of neuroendoscopic biopsy and endoscopic third ventriculocisternostomy (ETV) in patients with pineal region tumors between 2006 and 2019 in a single-center retrospective cross-sectional study with regard to diagnostic yield, hydrocephalus treatment, as well as impact on further antitumoral management. Out of 28 identified patients, 23 patients presented with untreated hydrocephalus and 25 without histological diagnosis. One patient underwent open biopsy, and 24 received a neuroendoscopic biopsy with concomitant hydrocephalus treatment if necessary. Eighteen primary ETVs, 2 secondary ETVs, and 2 ventriculoperitoneal shunts (VPSs) were performed. Endoscopic biopsy had a diagnostic yield of 95.8% (23/24) and complication rates of 12.5% (transient) and 4.2% (permanent), respectively. ETV for hydrocephalus management was successful in 89.5% (17/19) with a median follow-up of more than 3 years. Following histological diagnosis, 8 patients (28.6%) underwent primary resection of their tumor. Another 9 patients underwent later-stage resection after either adjuvant treatment (n = 5) or for progressive disease during observation (n = 4). Eventually, 20 patients received adjuvant treatment and 7 were observed after primary management. One patient was lost to follow-up. Heterogeneity of pineal region tumor requires histological confirmation. Primary biopsy of pineal lesions should precede surgical resection since less than a third of patients needed primary surgical resection according to the German pediatric brain tumor protocols. Interdisciplinary decision making upfront any treatment is warranted in order to adequately guide treatment.

Visual-Controlled Endoscopic Biopsy of Paraventricular Intraparenchymal Tumors

Frame-based stereotaxy represents the gold standard for biopsy of deep-seated lesions. Visual control of possible bleeding in these lesions is not possible. Neuroendoscopic biopsy represents an alternative procedure for tissue sampling in deep-seated intraventricular lesions. The authors present a technique for transventricular-navigated endoscopic biopsy of lesions that are located in the paraventricular region. Biopsy of paraventricular pathologies was performed in 6 male and 6 female patients between March 2013 and September 2018. The patient age ranged from 18 to 82 years. All patients underwent a pure endoscopic procedure over a burr hole trepanation supported by frameless navigation of the sedan probe. Histologic diagnoses were established in all biopsies. In all patients, a direct control of the biopsy area was feasible, and hemostasis could be obtained. In 5 patients, endoscopic third ventriculostomy was performed first due to obstructive hydrocephalus. In 1 patient suffering from obstructive hydrocephalus, a pellucidotomy was performed. In 9 cases, the initial postoperative course was uneventful. Three patients suffered from persistent hydrocephalus and had to be treated with ventriculoperitoneal shunt insertion. Endoscopically conducted biopsies with the aid of navigated tracking of the probe represent a possible additional technique in selected paraventricular intraparenchymal pathologies. The endoscopic approach enables the direct visualization of the intraventricular surface and its vessels. In contrast to standard stereotactic biopsy, direct visual control of hemostasis can be obtained even in paraventricular tumors.

Is there variable neuronal susceptibility to compression?

A 12-year-old boy with suprasellar germinoma complicated by hydrocephalus was found to have dorsal midbrain syndrome and bilateral compressive optic neuropathy. Following a third ventricular neuroendoscopic biopsy and the initiation of chemotherapy, a follow-up magnetic resonance imaging scan of the brain showed significant regression of the tumor with resolution of hydrocephalus. On smooth pursuit, there was significant improvement in upgaze. However, light-near dissociation of his pupillary defect was persistent. Fundal examination showed persistent temporal pallor of the optic discs bilaterally, associated with a suboptimal best-corrected visual acuity of 20/40 and bilateral centrocecal scotoma.The differential recovery of neuronal function following relief of compression is poorly understood. In this case, both the optic nerve and pretectal axonal fibers responsible for pupillary reflex, with their neuronal cell bodies residing outside the direct compressive site at the midbrain, showed poor functional recovery. However, relief of pressure at the rostral interstitial medial longitudinal fasciculus and posterior commissure nuclear complexes resulted in significant clinical improvement in upgaze.
 This case suggests that, for neurons, axons are apparently more susceptible to pressure than cell bodies. The predominant transmission of nerve impulses takes place through the length of axons, and thus is more sensitive to pressure changes, with the associated microvascular compromise and demyelination.
 

Neuroendoscopic biopsy: analysis of a series of 80 patients

Neuroendoscopy enables diagnostic biopsy of intraventricular and/or paraventricular tumors and the simultaneous treatment of associated hydrocephalus in selected cases. The objective of this paper was to analyze the effectiveness and safety of this procedure. This retrospective study included 80 patients between 2months and 78years old diagnosed with intraventricular and/or paraventricular expansive lesion who underwent neuroendoscopic biopsy from 2004 to 2016. Collected variables were gender, age at diagnosis, clinical presentation, tumor location, surgical technique, management of hydrocephalus, pathological findings, procedure-related complications, and follow-up time. Neuroendoscopic biopsy was performed in 80 patients. Mean age at diagnosis was 27years, and 52.5% were men. According to the Depreitere Classification, 71 were level I (conclusive diagnosis), 1 level III (problematic categorization), and 8 level IV (non-interpretable diagnosis). The most frequent diagnosis was grade I astrocytoma (14%). Diagnostic success per patient was 88.7%. Sixty-nine patients had hydrocephalus at diagnosis, 37 of whom were treated with endoscopic third ventriculostomy (ETV), with septostomy (SPT) in 14, and only SPT in 4. Twenty-eight patients underwent ventricular peritoneal shunt (VPS), with SPT in 20. The ETV success rate was 70.9%. The complication rate per patient was 11%: five patients presented intraventricular hemorrhage, three of whom died; one patient presented cerebrospinal fluid fistula; three presented transient oculomotor impairment. Postoperative follow-up was from 1month to 12.4years (mean 45months). Neuroendoscopy is an effective procedure for the pathological diagnosis of intraventricular and paraventricular tumors, allowing the treatment of associated hydrocephalus. Nevertheless, it is not exempt from serious complications and requires proper training.

GERM-20. NEUROENDOSCOPIC BIOPSY OF INTRACRANIAL GERM CELL TUMORS: ACCURACY AND COMPLICATIONS

Intracranial germ cell tumors (GCTs) are a heterogeneous group of lesions. It is important to obtain the accurate histological diagnosis since the treatment outcomes can depend on histology. Neuroendoscopic biopsy is a minimally invasive procedure and employed widely. But it is not yet clear whether neuroendoscopy can make so accurate diagnosis as craniotomy without increasing the risk of dissemination. We compared the diagnostic rate and recurrence rate of these two procedures. Forty patients with intracranial GCTs treated in our institute from 2007 to 2017 were included in this study. More than 6 pieces of tumor tissues were obtained with neuroendoscopy. As highly elevated tumor marker signifies highly malignant tumor, we started treatment without a histological diagnosis. For all patients except those with extremely highly elevated tumor markers, the histological diagnoses were made by neuroendoscopy or craniotomy. Of number cases with germinoma, 3 cases (neuroendoscopy 2, craniotomy 1) relapsed. All three cases were treated with additional chemotherapy and/or radiotherapy to survive. Of number cases with intermediate risk group tumors, 1 case who underwent craniotomy developed recurrence. High-risk tumors were diagnosed by tumor markers in 2 patients, 5 by endoscopy and one by craniotomy. One patient thought to be intermediate risk group by tumor marker, obtained the histological diagnosis of yolk sac tumor. The recurrence rate for neuroendoscopy and craniotomy was 8% and 15% respectively. Neuroendoscopy is useful for histological diagnosis as well as craniotomy and would not increase recurrence rate.

Quantification of the stress generated by the endoscopic movement in the brain parenchyma during intra ventricular surgical procedure

Endoscopy is increasingly used for intra ventricular surgeries such as hydrocephalus and tumor removal (Miwa et al. 2015 Miwa T, Hayashi N, Endo S, Ohira T. 2015. Neuroendoscopic biopsy and the treatment of tumor-associated hydrocephalus of the ventricular and paraventricular region in pediatric patients: a nationwide study in Japan. Neurosurg Rev.[Crossref], [PubMed], [Web of Science ®], , [Google Scholar]). Robotic based surgeries are more and more developed to control the trajectory and the movement of the endoscope and then to enhance the accuracy of surgical procedures and to reduce post-operative issues. The use of computer- aided robot is then well-suited to accurately reach ventricles cavities through the brain parenchyma and to minimize cerebral damage caused by the movement of the endoscope. On a mechanical point of view, moderate and severe traumatic brain injury (TBI) had a 50% risk to locally occur when Von Mises stress respectively exceeds 18 and 38 kPa (Willinger & Baumgartner 2003 Willinger R, Baumgartner D. 2003. Human head tolerance limits to specific injury mechanisms. Int J Crashworthiness.[Taylor & Francis Online], , [Google Scholar]). The purpose of this study was to assess the Von Mises stress generated in the brain by the endoscopic movement.

Pitfalls of Neuroendoscopic Biopsy of Intraventricular Germ Cell Tumors

A neuroendoscopic biopsy has become common for the diagnosis of ventricular tumors. However, its utility in patients with germ cell tumors (GCTs) has not been well discussed. We examined the usefulness and pitfalls of neuroendoscopic biopsies of intraventricular GCTs at a single institution. We retrospectively studied 21 consecutive patients diagnosed with GCTs by a neuroendoscopic biopsy of the ventricular region via the lateral ventricle. We examined the localization of tumors, histologic diagnoses using biopsies, surgical complications, and consistency of the diagnosis at the latest follow-up. Tumor specimens were obtained from a pineal lesion (n= 20), neurohypophysial lesion (n= 5), and lateral ventricular wall lesion (n= 2). In 5 patients, the specimens were obtained from multiple areas. The initial diagnoses were pure germinoma (n= 16), immature teratoma (n= 1), yolk sac tumor (n= 1), and mixed GCT (n= 3). Six of 21 patients needed a second transcranial removal of enhanced residual lesions in the course of the treatment. A discrepancy in the histologic diagnosis between 2 surgeries occurred in 3 patients: All 3 patients had a new diagnosis of teratoma component following transcranial surgery. No postoperative mortality or permanent morbidity related to the neuroendoscopic procedures was noted. Neuroendoscopic biopsies are safe and useful for obtaining reliable histologic diagnoses in the management of GCTs. However, for GCTs with mixed histology, biopsies are susceptible to diagnostic errors, especially missing detecting a component of teratoma.

Neuroendoscopic biopsy and the treatment of tumor-associated hydrocephalus of the ventricular and paraventricular region in pediatric patients: a nationwide study in Japan.

A neuroendoscopic biopsy is a minimally invasive and useful procedure for the diagnosis and initial management of tumor-associated hydrocephalus. We describe the nationwide investigation of the current status of neuroendoscopic biopsy for intra- and paraventricular tumors in children, as well as the treatment of tumor-associated hydrocephalus in pediatric patients. The main items examined included the patient's age and sex, location of the tumor, pathological diagnosis, complications, treatment and efficacy of treatment of the tumor-associated hydrocephalus, and the dissemination during the postoperative course. Two hundred twenty-one pediatric patients (mean 8.6years) from 67 institutions were registered. Endoscopic tumor biopsies were performed in 206 patients (93.2%), and a histopathological diagnosis could be performed in 195 of these 206 patients (94.7%). The most frequently histopathologically diagnosed tumor was a germ cell tumor (41.5%), followed by astrocytic tumors (24.1%) and cystic lesions (15.9%). Associated hydrocephalus was observed in 177 patients (80.1%), 101 of whom underwent endoscopic third ventriculostomy (ETV). The efficacy rate of the ETV in the perioperative period was 99.0%, and the long-term response rate was 90.1%. Perioperative complications other than fever were found in 24 patients (10.9%). In the statistical analysis, pediatric long-term response rate to ETV (p = 0.025) showed significantly more favorable results for pediatric than adult patients (p < 0.05). Neuroendoscopic procedures involving pediatric intra- and paraventricular tumors were considered to be very useful, with a low incidence of complication, and were associated with higher safety.

Neuroendoscopic biopsy of brain lesions: accuracy and complications.

The authors conducted a study to analyze the accuracy of neuroendoscopic biopsies of ventricular and periventricular lesions and record any difficulties or complications of the neuroendoscopic biopsy procedure. A total of 50 patients with different diseases consecutively underwent endoscopic biopsy procedures. The biopsy result was considered diagnostic if the pathologist reported any specific finding on which clinicians could base decisions about treatment or observation. The biopsy result was referred to as accurate if the results matched results of a sample obtained later or if the treatment response and disease evolution were compatible with the diagnosis. The biopsy result was considered inaccurate if results showed any relevant differences from those of the later sample or if the patient's disease did not evolve as expected. Complications were recorded and compared with those found in a literature review. For 2 patients, the procedure had to be terminated. The biopsy diagnostic rate was 89.6%, and the accuracy rate was 86%. Complications associated with the procedure were 3 hemorrhages (6%), 2 infections (4%), and 1 death (2%); no reoperations were needed. Endoscopic biopsy seems to be an accurate procedure with acceptable morbidity and mortality rates.

O5.09 * VENTRICULAR HIGH GRADE GLIOMA: NEUROENDOSCOPY AND ADJUVANT THERAPY

INTRODUCTION: In ventricular high grade glioma the obstructive hydrocephalus and the subsequent neurological worsening are usually the limit for chemotherapy and radiotherapy. Recently, in ventricular tumours causing obstructive hydrocephalus neuroendoscopy has gained even more appeal as a first choice procedure since it is possible to simultaneously perform tumour biopsy and endoscopic third ventriculostomy (ETV) or septostomy. The immediate relief of intracranial hypertension and the availability of specimens for a pathological diagnosis allow time for planning the most suitable treatment strategy based on histological diagnosis and CSF tumour markers. METHODS: Since 2001 in 35 patients affected by hydrocephalus due to a ventricular tumour the neuroendoscopic biopsy was performed. In 15 patients ( age 17 - 79 yrs) the NMR showed hydrocephalus due to an infiltrating tumour with contrast enhancement: in 7 inside the third ventricle, in 8 inside the lateral ventricle. In all patients the clinical signs of progressive intracranial hypertension at admission were present. After neuroendoscopy and histological diagnosis radiotherapy and/or chemotherapy were performed. RESULTS: In 14 patients the biopsy was performed, while in one case of occipital corn tumour was abandoned. In 9 cases tumour biopsy the Tu laser for bleeding control and tumour ablation was used. The histology was: in 10 GBM, in 1 malignant PNET, in 1 malignant xanthoastrcytoma, in 1 anaplastic ependymoma, 1 metastasis. During the same neuroendoscopic procedure in 7 cases the third ventricolostomy (ETV) and in 4 the septostomy were realized. In 12 patients the clinical outcome improved and radiotherapy and chemotherapy were possible. The median overall survival was 4 months (2 - 12) for progression disease. CONCLUSION: Based on our experience, the neuroendoscopic biopsy should be considered in the diagnosis and therapy of ventricular tumours, allowing subsequent tumor therapy. Furthermore, CSF pathways can be restored by ETV or septostomy to control intracranial hypertension. By improving the clinical outcome radiotherapy and /or chemotherapy in high grade glioma is possible.

Supra-interthalamic adhesion approach: a modified surgical approach for neuroendoscopic biopsy of pineal tumors.

Since the first introduction of modern-style flexible neuroendoscopy by Fukushima et al. in 1973, the instruments and surgical techniques for diagnosis and therapeutic use of neu r oendo s copy have deve l oped r ap i d l y [ 5 ] . Neuroendoscopic tumor biopsy in and around the ventricles has become a standard surgical procedure in the last two decades [1, 3, 4, 6–8, 11–14]. Pineal tumors often present with symptoms associated with hydrocephalus and are regarded as one of the best indications for neuroendoscopic biopsy [2, 4, 15, 16]. In such situations, endoscopic third ventriculostomy (ETV) is performed simultaneously with tumor biopsy. The most commonmethod is to perform ETV first and then with the endoscope redirected to the dorsally situated pineal tumor [12]. The endoscope is usually moved along the floor of the third ventricle under the interthalamic adhesion (ITA) (the massa intermedia) [7, 8]. Using this approach, only the lower part of the tumor would come into the neuroendoscopic surgical view in some cases [15], and biopsy specimens can only be obtained from a limited part of the tumor. Furthermore, some tumors in the pineal region are highly vascular and, with this infra-ITA approach, bleeding is likely to interfere with neuroendoscopic biopsy. An insufficient biopsy specimen can lead to incorrect diagnosis of the tumor [11]. On rare occasions, bleeding can even force neurosurgeons to suspend the neuroendoscopic procedure [1, 2, 15]. We have modified the neuroendoscopic surgical approach to pineal tumors as an adjunct to the standard infra-ITA approach. It would be natural to speculate that the supra-ITA approach could have been done by others since the endoscopic surgery of the pineal tumors or the lesion in the posterior half of the third ventricle is regarded as a routine procedure. However, details of the supra-ITA approach have not been described so far. Here, the authors focused on the supra-ITA approach and discussed extensively on the anatomical background, efficacy, advantages, and limitations of the procedure (Fig. 1).

Neuroendoscopic biopsy of pediatric brain tumors with small ventricle

Intraventricular endoscopic procedures to resect or biopsy peri- or intraventricular tumors may have not been used in patients with small ventricles due to the presumed difficulties with ventricular cannulation and the perceived risk of morbidity. The purpose of this study is to review the feasibility and safety of neuroendoscopic procedures in the biopsy of pediatric brain tumors with a small ventricle. Between January 2006 and January 2013, 72 children were identified with brain tumors confirmed by transventricular endoscopic biopsy. Patients were divided into non-hydrocephalus and hydrocephalus groups, and the ratio of the two groups was 20:52. In 20 pediatric brain tumors with small ventricle, the targeted lesion was successfully approached under the guidance of neuronavigation. Navigational tracking was especially helpful in entering small ventricles and in approaching the third ventricle through the narrow foramen of Monro. The histopathologic diagnosis was established in all 20 patients: nine germinomas, three mixed germ cell tumors, two pilomyxoid astrocytomas, and two pilocytic astrocytomas. The tumor biopsy sites were the suprasellar area (n = 10), pineal area (n = 4), lateral ventricular wall (n = 4), and mammillary body (n = 1). There were no major morbidities related to the endoscopic procedure. Neuroendoscopic biopsy or resection of peri- or intraventricular tumors in pediatric patients without hydrocephalus is feasible. Navigation-guided neuroendoscopic procedures improved the accuracy of the neuroendoscopic approach and minimized brain trauma. The absence of ventriculomegaly in patients with brain tumor may not serve as a contraindication to neuroendoscopic tumor biopsy.

Narrow band imaging-guided endoscopic biopsy for intraventricular and paraventricular brain tumors: clinical experience with 14 cases

Narrow-band imaging (NBI) has been confirmed as a useful endoscopic technique to distinguish neoplasm from normal tissue, on the basis of the enhanced neovascularity of tumor tissue. NBI-guided tissue biopsy for laryngopharyngeal and digestive lesions is a novel methodology, but the feasibility for central nervous system tumors remains unclear. The aim of our study was to evaluate the feasibility of NBI-guided biopsy for intraventricular and paraventricular tumor. Fourteen patients with intraventricular or paraventricular tumors underwent neuroendoscopic biopsy using a videoscope with NBI. Ventricular walls and tumors were observed using conventional imaging, followed by NBI. Colors of ventricle walls and tumors visualized using NBI were compared to those visualized under conventional imaging. Extracted specimens were stained using CD31 antibody and numbers of microvessels in each specimen were counted for analyzing vascular density. Normal ventricle walls were a similar color under conventional imaging and NBI. Tumor surfaces appeared to be cyan in color under NBI. Vessels on the tumor were more clearly visualized with NBI than with conventional imaging. NBI was able to identify tumor surfaces that were not perceptible on conventional imaging. All specimens in the lesion surfaces from cyan-colored areas under NBI contained tumor cells. Specimens extracted from regions that appeared cyan in color under NBI (51.0 vessels/mm(2)) had significantly greater vascular density than regions that appeared a normal color (17.4 vessels/mm(2); p = 0.039). NBI-guided biopsy of intraventricular and paraventricular tumors is feasible for visualizing tumor surface-enhancing neovascularities. NBI would contribute to accurate histological diagnosis while minimizing injury to surrounding structures.

Application of indocyanine green (ICG) fluorescence for endoscopic biopsy of intraventricular tumors

Many reports have already indicated the benefit of pathological diagnosis of intra- and periventricular tumors with neuroendoscopic biopsy. However, it is also well known that studies can be occasionally inconclusive because of the small and/or inadequate samples for identification of abnormal tissues. The application of indocyanine green (ICG) fluorescence for endoscopical tumor biopsy under the intraventricular surroundings is a new area not previously reported. We attempted visual differentiation of intraventricular lesions from the surrounding structure using ICG fluorescence and considered the most appropriate region for biopsy. Three cases (13–14 year-old boys) with secondary hydrocephalus caused by intra- and periventricular tumors were operated for endoscopic transventricular biopsy combined with endoscopic third ventriculostomy. Final pathological diagnoses were suprasellar malignant lymphoma and germ cell tumors in two patients, both associated with intraventricular dissemination. Enhanced tumor visualization with 12.5 mg of ICG administration was obtained using the D-light P light equipment and ICG telescope 5.8 mm/19 cm. It was possible to identify the tumor mass margins themselves and detect the differences of intratumoral ICG accumulation. The areas of tumor dissemination were identifiable by neuroendoscopy but unable to be visualized by ICG fluorescence. We were able to obtain an ICG fluorescence imaging inside the cerebral ventricles by new D-light P system comprised of a camera head telescope. ICG fluorescence with neuroendoscopy can provide useful information for choosing the point of biopsy of intra- and periventricular tumors. However, we need to assess if the ICG accumulation site is the most appropriate for biopsy.

Transventricular endoscopic biopsy of suprasellar tumors: a pediatric case series

The purpose of this study was to investigate the efficacy and safety of transventricular neuroendoscopic biopsies in pediatric patients with suprasellar tumors. Twenty-three pediatric patients (12 males and 11 females) with suprasellar tumors underwent transventricular neuroendoscopic biopsy at our institute by a single surgeon from 2000 to 2011. Neuronavigation has been combined with endoscopic procedures since 2008. Neuroendoscopic biopsies were performed to verify the histopathological diagnosis of neoplasms and to plan appropriate treatment strategies. Neuroendoscopic biopsy specimens were appropriate for diagnosis in 22 of the 23 patients (95.7%) and revealed 14 germ cell tumors (12 germinomas, one choriocarcinoma, and one immature teratoma), seven astrocytomas, and one craniopharyngioma. Subsequent treatment modalities including chemotherapy, radiation therapy, or microscopic surgery were determined according to the pathological findings. Seventeen of the 23 patients (73.9%) showed ventriculomegaly. Among them, ventriculomegaly in 14 patients was resolved after an endoscopic procedure and/or adjuvant chemotherapy, but the remaining three patients (17.6%) required a ventriculoperitoneal shunt to relieve the ventriculomegaly. The pathologic diagnosis of these three patients was uniformly a large astrocytoma. Navigational tracking was helpful to enter small ventricles and the narrow foramen of Monro in patients without hydrocephalus. No mortalities were related to the procedures, but three transient diabetes insipidus (13.0%) cases occurred but fully recovered before the patients received adjuvant therapy. Endoscopic biopsy is feasible and shows acceptable operation-related complications to obtain tissue from suprasellar tumors in pediatric patients. Navigation-assisted neuroendoscopic procedure improves the accuracy of the endoscopic approach. An associated endoscopic procedure can resolve hydrocephalus, but it has limitations with large ventricle-occupying tumors.