APPLICATION OF NEUROENDOSCOPY TO INTRAVENTRICULAR LESIONS

Quantitative analysis of exposure and surgical maneuverability of three purely endoscopic keyhole approaches to the floor of the third ventricle

BACKGROUND

The quantitative anatomic analysis of comprehensively endoscopic approaches to the third ventricle is scarce at present. The objective of the study is to quantitatively assess and compare the exposure and microsurgical maneuverability of three absolutely endoscopic keyhole approaches, including interhemispheric transcallosal transchoroidal (TCTC), frontal transforminal transchoroidal (TFTC) and supraorbital subfrontal translamina terminalis (SFTL) approaches.

METHODS

Anatomical dissections and exposure of the important structures of the third ventricle were performed using six formalin-fixed cadaveric human heads (twelve sides) under endoscope. Tubular retractor system was used in the TFTC approach. Quantitative anatomical relationship between the important landmarks were obtained. Moreover, the exposure and surgical operability of three approaches were evaluated through applying the rating scale and accomplishing the quantitative anatomic analysis, area of surgical freedom and angle of attack.

RESULTS

The mediolateral, anteroposterior (AM: between aqueduct and mammillary body; IM: between infundibular recess and mammillary body) and superoinferior distance of TCTC, TFTC and SFTL approaches were 4.0±1.0, 4.2±0.4, 4.1±1.1 mm; 17.3±1.4, 17.6±0.5, 12.8±3.3 mm (AM); 7.7±0.3, 7.8±0.5 mm, not measured (IM); and 5.6±0.3, 7.8±0.8, 7.8±1.5 mm, respectively. Similar to TFTC, the exposed landmarks of TCTC were almost scored a "4" by three neurosurgeons except the infundibular recess scored a "3" according to the rating scale. During the SFTL approach, apart from the roof, the majority of the landmarks were scored a "4" except for the infundibular recess, which was scored a "3." The mean area of surgical freedom of TCTC (0° endoscope: 220±47; 30°: 247±56 mm2) was not significantly different from that of TFTC approach (0° endoscope: 216±49; 30°: 245±53 mm2) under same endoscope, P>0.05. Mean angle of attack of TCTC (0° endoscope: 21±4°; 30°: 26±4°) was significantly larger than that of TFTC approach (0° endoscope: 16±3°; 30°: 19±3°), P<0.05.

CONCLUSIONS

Purely endoscopic TCTC and TFTC approaches offer brilliant exposure of the anterior, middle and posterior third ventricle. TCTC approach may have better surgical maneuverability than TFTC approach. Despite the long working distance, the whole third ventricle are exposed well except for the roof in the SFTL approach, and surgical manipulation can be accomplished smoothly.

Exoscopic microneurosurgery in pediatric brain tumors: an ideal tool for complex and peculiar anatomo-topographic scenarios?

PURPOSE

Since its introduction in the 1950s, the microsurgical paradigm has revolutionized neurosurgery. New technologies have been introduced over the years trying to overcome limits of the classical operating microscope. The recently developed 3D exoscopes represent a potential new paradigm for micro-neurosurgery. We analyzed our own experience with a 4 K-3D exoscope in a series of pediatric brain tumors to verify its advantages and limitations in comparison to the operating microscope and in light of the literature.

METHODS

Twenty-five pediatric patients with brain tumors underwent surgery at our Institute; the population has been analyzed and described. A score to evaluate the exoscopes and compare it to the operating microscope was considered and postoperatively applied to each single case.

RESULTS

The exoscope appears to be at least comparable to the operating microscope (OM) in all analyzed aspects. In the case of deep-seated or fourth ventricle tumors, the exoscope seems to be superior to the microscope. A surgeon-dependent learning curve is necessary for neurosurgeons to be confident with the exoscope.

CONCLUSION

Exoscopes appear to be as safe and effective as operating microscopes in pediatric neuro-oncological surgery. They have some advantages that make them superior to microscopes, particularly regarding surgeon ergonomics and fatigue, visual field qualities, and higher choice of intraoperative viewing angles.

Intraventricular Tumors: Surgical Considerations in Lateral and Third Ventricular Tumors

Management of lateral and third ventricular tumors has been a challenge for neurosurgeons. Advances in imaging and pathology have helped in a better understanding of the treatment options. Technical refinement of microsurgical technique and addition of endoscopy has enabled more radical excision of tumors, when indicated, and added more safety.A proper understanding of the pathology at various ages and treatment options is continuously evolving. Many pediatric tumors are amenable to conservative surgical methods with effective complementary treatments. However, radical surgery is required in many adults as the main treatment and for many benign tumors. Various intraventricular lesions encountered and their surgical management is reviewed here for their efficacy, safety, and outcome, encompassing changes in our practice over the last 20 years.

The minimally invasive transventricular endoscopic approach to third ventricular lesions in pediatric patients-all-rounder with limitations?

INTRODUCTION

The surgical management of third ventricular lesions poses unique challenges, requiring careful consideration of various approaches and techniques. This study focuses on the transventricular transforaminal endoscopic approach and aims to provide insights into its indications, limitations, technical nuances, and potential complications in pediatric patients.

METHODS

A retrospective analysis was conducted using data from a 13-year period on pediatric patients who were subjected to transforaminal endoscopic surgery for third ventricular lesions. The study utilized a prospectively maintained internal database, extracting demographic data, preoperative assessment, surgical details, and postoperative follow-up information. The surgical technique is presented in detail, and exemplary case reports highlight relevant surgical considerations.

RESULTS

Out of 578 endoscopic transforaminal procedures, 24 surgeries were performed on pediatric patients with third ventricular lesions. Performed procedures consisted of cyst resection (13 cases), solid tumor resection (4 cases), and tumor biopsies with CSF pathway restoration (7 cases). The mean age at the time of surgery was 7.6 years. Postoperatively, 14 patients showed transient nausea and vomiting (58.3%); 10 patients showed pneumocephalus on postoperative MRI (41.7%). No emergency postoperative re-interventions nor perioperative mortality were observed.

CONCLUSION

The endoscopic transventricular transforaminal approach is a safe approach for lesion resection, CSF pathway restoration, and tumor biopsy in pediatric patients with third ventricle lesions. The author's results support the use of this minimally invasive technique as an alternative to more extensive approaches, particularly to the interforniceal interhemispheric approach. However, surgical success is highly dependent to the individual surgeon's experience and moreover to a suitable indication setting. Careful preoperative planning and knowledge of the approaches' pro and cons is mandatory for successful application of this approach.

Application of endoport-assisted neuroendoscopic techniques in lateral ventricular tumor surgery

Objective

The objective of this study was to investigate the clinical experience and therapeutic efficiency of Endoport-assisted neuroendoscopic surgery for resection of lateral ventricular tumors. The key points and application value of this surgical technique were additionally discussed.

Methods

A retrospective analysis was conducted on the clinical and follow-up data of 16 patients who underwent endoport-assisted neuroendoscopic surgery for lateral ventricular tumors at the Department of Neurosurgery, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, between January 2018 and September 2020. The surgical procedures, complications and outcomes were analyzed.

Results

The study included a total of 16 patients (5 males and 11 females) with lateral ventricular tumors, with a mean age of 43.2 years (18-70 years old). The tumors were distributed as follows: 5 cases involved the body of the lateral ventricle, 3 involved the frontal horn and body, 3 involved the occipital horn, 2 involved the trigone, 2 involved the frontal horn, and 1 case involved the occipital horn and body. Perioperative complications were analyzed, revealing 1 case of intraoperative acute epidural hematoma intraoperative and 2 cases of postoperative obstructive hydrocephalus. All complications were promptly managed. Postoperative MRI revealed that 14 cases (88%) achieved total resection, while 2 cases (12%) achieved subtotal resection. During the follow-up of 6-38 months, no recurrence was observed. The patient diagnosed with glioblastoma died 16 months after surgery (GOS=1), while the remaining patients have successfully resumed to normal daily life with a GOS score of 5.

Conclusion

In conclusion, endoport-assisted neuroendoscopic surgery proved to be a minimally invasive and effective technique for resecting lateral ventricular tumors, with acceptable complications. It effectively utilizes the benefits of close observation, comprehensive exposure, and reduced tissue damage. Therefore, endoport-assisted neuroendoscopic surgery is suitable for the resection of lateral ventricular tumors.

Predictors of intraoperative intracranial aneurysm rupture in patients with subarachnoid hemorrhage: a retrospective analysis

PURPOSE

Intraoperative cerebral aneurysm rupture (IOR) is a common phenomenon with a frequency of around 19%. Research regarding IOR lacks an analysis of its predictors.

METHODS

We retrospectively examined all saccular aneurysms, in 198 patients with subarachnoid hemorrhage, surgically treated from 2013 to 2019. Operative reports, patient histories, blood test results, discharge summaries, and radiological data were reviewed. IOR was defined as any bleeding from the aneurysm during surgery, preceding putting a clip on its neck, regardless of how trivial.

RESULTS

The frequency of IOR was 20.20%. Patients with IOR had higher aneurysm dome size (9.43 ± 8.39 mm vs. 4.96 ± 2.57 mm; p < 0.01). The presence of blood clot on the aneurysm dome was significantly associated with IOR (12.50% vs. 2.53%; p < 0.01). We also associated lamina terminalis fenestration during surgery (7.50% vs. 21.52%; p = 0.04) and multiple aneurysms (5.00% vs. 18.35%; p = 0.038) with a lower risk of IOR. Glucose blood levels were also elevated in patients with IOR (7.47 ± 2.78 mmol/l vs. 6.90 ± 2.22 mmol/l; p = 0.04). Multivariate analysis associated that urea blood levels (OR 0.55, 0.33 to 0.81, p < 0.01) and multiple aneurysms (OR 0.04, 0.00 to 0.37, p = 0.014) were protective factors against the occurrence of IOR.

CONCLUSION

Large dome size of an aneurysm, a blood clot on the aneurysm dome and elevated glucose blood levels can be IOR predictive. Lamina terminalis fenestration, the appearance of multiple aneurysms, and high urea blood levels may be associated with a lower risk of such an event.

The Future of Neuroendoscopy: Looking Ahead Through a Lens

Neuroendoscopy has progressed remarkably in the past few decades. Ventriculoscopy, skull base endoscopy, and spinal endoscopy are now part of routine practice in the neurosurgical treatment of numerous pathologies. Like other developing fields, however, it faces numerous challenges and obstacles that must be overcome for the field to continue to evolve and expand. This brief review of new and exciting developments in neuroendoscopy describes some of the most interesting directions the field is starting to steer towards.

Neuroendoscopy: history, endoscopes, and instrumentation

INTRODUCTION

Endoscopy was first employed in the surgical treatment of neurosurgical diseases early in the twentieth century, but did not become an established practice for a long time, mainly because of poor technology and clinical results. After a slow re-appearance in the 1980s, the 1990s saw an explosion of techniques and instrumentation. Continuing technological improvement has led to further expansion of surgical techniques and indications for use of neuroendoscopy.

DISCUSSION

The expansion of ventricular endoscopy has led to significant understanding of CSF disorders. Aqueduct stenosis as cause of hydrocephalus and arachnoid cysts are an example of pathologies, the concept and understanding of which now is considerably enhanced, due to the application of neuroendoscopy in their treatment. Management of loculated hydrocephalus has been facilitated considerably with the use of the endoscope. The concepts of aqueductoplasty, septostomy, and foraminoplasty of the foramina of Monro and Magendie emerged, which were previously unknown. Skull base surgery, especially surgery for craniopharyngioma, has seen dramatic improvement in results with the use of the endoscope. Coupling of the endoscope with neuronavigation has expanded technical capabilities even further. Overall, we can do a lot more with the endoscope now in comparison to 30 years ago.

CONCLUSION

We should always remember that the endoscope is only a tool. Its use has indications and limitations related to its design and our ability to extract the maximum, in the context of its shortcomings. Further technological advances will push surgical frontiers even more in years to come.

Using robotics to move a neurosurgeon's hands to the tip of their endoscope

A major advantage of surgical robots is that they can reduce the invasiveness of a procedure by enabling the clinician to manipulate tools as they would in open surgery but through small incisions in the body. Neurosurgery has yet to benefit from this advantage. Although clinical robots are available for the least invasive neurosurgical procedures, such as guiding electrode insertion, the most invasive brain surgeries, such as tumor resection, are still performed as open manual procedures. To investigate whether robotics could reduce the invasiveness of major brain surgeries while still providing the manipulation capabilities of open surgery, we created a two-armed joystick-controlled endoscopic robot. To evaluate the efficacy of this robot, we developed a set of neurosurgical skill tasks patterned after the steps of brain tumor resection. We also created a patient-derived brain model for pineal tumors, which are located in the center of the brain and are normally removed by open surgery. In comparison, testing with existing manual endoscopic instrumentation, we found that the robot provided access to a much larger working volume at the trocar tip and enabled bimanual tasks without compression of brain tissue adjacent to the trocar. Furthermore, many tasks could be completed faster with the robot. These results suggest that robotics has the potential to substantially reduce the invasiveness of brain surgery by enabling certain procedures currently performed as open surgery to be converted to endoscopic interventions.

Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Hypothalamic Hamartoma: Surgical Approach and Treatment Outcomes

Hypothalamic hamartoma (HH) is a rare lesion consisting of normal neurons and neuroglia arranged in an abnormal pattern which usually causes gelastic seizures (GS). Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has been developed as a minimally invasive approach to treat HH and gradually become a first-line treatment. In total, this study enrolled 47 consecutive HH patients that underwent one round of ablation. Patients were followed for at least one year. Patients' medical records and surgical information were carefully reviewed, and univariate analyses were performed. Of the treated patients, 72.3% remained GS-free in this study, with an overall Engel class I rate of 68.1%. Long-term postoperative complications occurred in six patients. Factors associated with GS prognosis included Delalande classification (p = 0.033), HH volume (p = 0.01), and the ablation rate of the HH body (p = 0.035). The disconnection rate was 0.73 ± 0.14 in the Engel class Ia group as compared to 0.62 ± 0.13 in the Engel Ib-Engel IV group (p = 0.046). MRgLITT represents a safe and effective surgical procedure. Patients with larger or Delalande type IV HH may require multiple rounds of ablation. In addition to assessing the degree of disconnection, ablation volume should also be carefully considered for patients undergoing this procedure.

Eccentric Tube Robots as Multiarmed Steerable Sheaths

This paper presents a novel continuum robot sheath for use in single-port minimally invasive procedures such as neuroendoscopy in which the sheath is designed to deliver multiple robotic arms. Actuation of the sheath is achieved by using precurved superelastic tubes lining the working channels used for arm delivery. These tubes perform a similar role to push/pull tendons, but can accomplish shape change of the sheath via rotation. A kinematic model using Cosserat rod theory is derived which is based on modeling the system as a set of eccentrically aligned precurved tubes constrained along their length by an elastic backbone. The specific case of a two-arm sheath is considered in detail. Simulation and experiments are used to investigate the validate the concept and model.

Evaluation of the precision of navigation-assisted endoscopy according to the navigation tool setup and the type of endoscopes

OBJECT

Preoperative image-based neuronavigation-assisted endoscopy during intracranial procedures is gaining great interest. This study aimed to analyze the precision of navigation-assisted endoscopy according to the navigation setup, the type of optic and its working angulation.

METHODS

A custom-made box with four screws was referenced. The navigation-assisted endoscope was aligned on the screws (targets). The precision on the navigation screen was defined as the virtual distance-to-target between the tip of the endoscope and the center of the screws. Three modifiers were assessed: (1) the distance D between the box and the reference array (CLOSE 13 cm - MIDDLE 30 cm - FAR 53 cm), (2) the distance between the tip of the endoscope and the navigation array on the endoscope (close 5 cm - middle 10 cm - far 20 cm), (3) the working angulation of the endoscope (0°-endoscope and 30°-endoscope angled at 90° and 45° with the box).

RESULTS

The median precision was 1.3 mm (Q1: 1.1; Q3: 1.7) with the best setting CLOSE/close. The best setting in surgical condition (CLOSE/far) showed a distance-to-target of 2.3 mm (Q1: 1.9; Q3: 2.5). The distance D was correlated to the precision (Spearman rho = 0.82), but not the distance d (Spearman rho = 0.04). The type of optic and its angulation with the box were also correlated to the precision (Spearman rho =  - 0.37). The best setting was the use of a 30°-endoscope angled at 45° (1.4 mm (Q1: 1.0; Q3: 1.9)).

CONCLUSION

Navigated-assisted endoscopy is feasible and offers a good precision. The navigation setup should be optimized, reducing the risk of inadvertent perifocal damage.

Intraventricular Craniopharyngiomas-Overcoming Their Relative Inaccessibility: Institutional Experience With a Review of Literature

Introduction: Craniopharyngiomas constitute 2-4% of intracranial neoplasms. Intraventricular craniopharyngiomas (IVCrs) are the rarely encountered varieties of these lesions. Objective: The objective of the study was to study the special features in clinical presentation, imaging, management, and surgical outcome of IVCrs. Materials and Methods: This retrospective analysis included the combined experience from two tertiary care institutions. Medical records of histopathologically proven cases of IVCrs from January 1994 to June 2021 were assessed, and images were analyzed based on the criteria by Migliore et al. for inclusion of solely intraventricular lesion with the third ventricular ependyma demarcating it from the suprasellar cistern. Results: Among the 25 patients included (mean age: 35.4 years), the most common presentation included headache (n = 21, 84%), vomiting and other features of raised ICP (n = 18, 72%), visual complaints (n = 12, 48%), and endocrinopathies (n = 11, 44%). Fifteen had predominantly cystic tumors, two were purely solid, and eight were of mixed consistency. Primary open microsurgical procedures were performed in 18 (72%) patients, of which four (16%) were endoscope-assisted. Seven (28%) underwent a purely endoscopic procedure. One underwent a staged surgery with endoscopic cyst fenestration and intracystic interferon (IFN)-alpha therapy, followed by microsurgical excision. Complete excision was achieved in 10 patients, near-total in nine, and partial excision in six. Four patients underwent a ventriculoperitoneal shunt (one before the definitive procedure). At a median follow-up of 36 months (range:11-147 months), five patients developed a recurrence, and one had a stable small residue. This patient and two others with small cystic recurrences were observed. One patient was managed with radiotherapy alone. Another underwent re-surgery after a trial of radiotherapy, and the last patient developed a local recurrence, which was managed with radiotherapy; he then later developed an intraparenchymal recurrence, which was operated. Conclusion: Purely IVCrs present with raised intracranial pressure, and visual disturbances are less common. Their deep-seated location and limited surgical field-of-view makes minimally invasive endoscopic-assisted surgery most suitable for their excision. The thin-walled cystic lesions may be occasionally adherent to the ependymal wall in close vicinity to the thalamus-hypothalamus complex, making complete excision difficult. Their responsiveness to radiotherapy, often leads to a gratifying long-term outcome.

Surgical advances in the management of brain metastases

As the epidemiological and clinical burden of brain metastases continues to grow, advances in neurosurgical care are imperative. From standard magnetic resonance imaging (MRI) sequences to functional neuroimaging, preoperative workups for metastatic disease allow high-resolution detection of lesions and at-risk structures, facilitating safe and effective surgical planning. Minimally invasive neurosurgical approaches, including keyhole craniotomies and tubular retractors, optimize the preservation of normal parenchyma without compromising extent of resection. Supramarginal surgery has pushed the boundaries of achieving complete removal of metastases without recurrence, especially in eloquent regions when paired with intraoperative neuromonitoring. Brachytherapy has highlighted the potential of locally delivering therapeutic agents to the resection cavity with high rates of local control. Neuronavigation has become a cornerstone of operative workflow, while intraoperative ultrasound (iUS) and intraoperative brain mapping generate real-time renderings of the brain unaffected by brain shift. Endoscopes, exoscopes, and fluorescent-guided surgery enable increasingly high-definition visualizations of metastatic lesions that were previously difficult to achieve. Pushed forward by these multidisciplinary innovations, neurosurgery has never been a safer, more effective treatment for patients with brain metastases.

Neuroendoscopic Transventricular Approach for Cystic Craniopharyngioma

The literature is rich with many studies reporting different treatment modalities and approaches for cystic craniopharyngioma (CC), including microsurgery, neuroendoscopic transventricular approach, endoscopic transnasal surgery, stereotactic drainage, and Ommaya reservoir insertion. The goals of this manuscript are to report the successful treatment of an atypical case of CC using the neuroendoscopic transventricular approach (NTVA) as well as discuss the different surgical modalities for these tumors following a comprehensive review of the literature. Our patient is a nine-year-old female with a large CC who was managed using the NTVA. No complications or recurrence occurred over two years of follow-up. Results of our literature review showed lower recurrence and complication rates of the NTVA compared to other surgical modalities.The NTVA is potentially efficient, reliable, and safe for managing CC and cystic-dominant craniopharyngiomas, with low recurrence and complication rates compared to microsurgery and Ommaya reservoir insertion. Future randomized clinical studies comparing the various treatment modalities of CC are needed to solidify these conclusions.

Endoscopic and Endoscopically-Assisted Resection of Intraventricular Lesions Using a Neuroendoscopic Ultrasonic Aspirator

The development of minimally invasive neuroendoscopy has advanced in recent years. The introduction of the neuroendoscopic ultrasonic aspirator (NUA) broadened the treatment spectrum of neuroendoscopy. We aim to describe our experience with the use of NUA for the resection of intraventricular lesions. Here, we present consecutive retrospective case series of adult and pediatric patients undergoing resection of an intraventricular lesion with a NUA (Endoscopic Neurosurgical Pen, Söring GmbH, Quickborn, Germany) between January 2019 and April 2020. Eight patients between the age of 0.5 and 73 years underwent surgery using NUA and were included in this study. In four patients, an endoscopic assisted (EA) resection of the lesion was undertaken, while in four patients, the lesion was removed using purely endoscopic (PE) resection. In all cases, gross/near total resection was achieved. The average blood loss was 142.5 ± 90.4 mL (range 50–300 mL). Transient morbidity was seen in four patients (50%), while permanent morbidity or mortality did not occur. The NUA seems to be a safe and valuable tool for the minimally invasive resection of intraventricular lesions in selected cases. The type, size, consistency, and vascularization of the lesion limit at times the purely endoscopic use of the NUA.

Resection of intra- and paraventricular malignant brain tumors using fluorescein sodium-guided neuroendoscopic transtubular approach

BACKGROUND

The requirement of brain retraction and difficulty in distinguishing the tumor demarcation are challenging in conventional approaches to intra- and paraventricular malignant tumors (IV-PVMTs). Tubular retractors can minimize the retraction injury, and fluorescein-guided (FG) surgery may promote the resection of tumors. Our aim is to evaluate the feasibility, safety, and effectiveness of fluorescein-guided endoscopic transtubular surgery for the resection of IV-PVMTs.

METHODS

Twenty patients with IV-PVMTs underwent FG endoscopic transtubular tumor resection. Fluorescein sodium was administered before the dural opening. The intraoperative fluorescence staining was classified as "helpful" and "unhelpful" based on surgical observation. Extent of resection was assessed using postoperative magnetic resonance imaging. Karnofsky Performance Status (KPS) score was used to evaluate the general physical condition of patients.

RESULTS

There were 9 glioblastomas, 4 anaplastic astrocytomas and 7 metastatic tumors. "Helpful" fluorescence staining was observed in 16(80%) of 20 patients. Gross total resection was achieved in 16(80%) cases, near-total in 3(15%) cases, and subtotal in 1 (5%) case. No intra- or postoperative complications related to the fluorescein sodium occurred. The median preoperative KPS score was 83, and the median KPS score 3-month after surgery was 88.

CONCLUSION

FG endoscopic transtubular surgery is a feasible technique for the resection of IV-PVMTs. It may be a safe and effective option for patients with these tumors. Future prospective randomized studies with larger samples are needed to confirm these preliminary data.

Cytologic Features of Ventricular Tumors of the Central Nervous System: A Review with Emphasis on Diff-Quik Stained Smears

BACKGROUND

Neoplasms from the ventricular system share a common location but have highly variable histogenesis. Many are slowly growing tumors that behave in a benign fashion. They can be classified as primary and secondary tumors. The most common primary tumors are ependymomas, subependymomas, subependymal giant cell astrocytomas, central neurocytomas, choroid plexus tumors, meningiomas, germinomas, pineal parenchymal tumors, papillary tumors of the pineal region, chordoid gliomas, rosette-forming glioneuronal tumors of the fourth ventricle, and craniopharyngiomas. Pilocytic astrocytomas, medulloblastomas, and atypical teratoid/rhabdoid tumors often show secondary involvement of the ventricular system.

SUMMARY

Advances in neurosurgery have facilitated access to the ventricular system increasing the number of cases in which such tumors can be biopsied. In this context, cytology has been proven to be an extremely useful diagnostic tool during intraoperative pathologic consultations. Many ventricular tumors are infrequent, and the cytologic information available is limited. In this review, we describe the cytologic features of the uncommon ventricular tumors and report on unusual findings of the more common ones. For the cytologic evaluation of brain tumors, many neuropathologists prefer formalin fixation and hematoxylin and eosin staining. In this review, we highlight the cytologic findings as seen with Diff-Quik, a very popular staining method among cytopathologists. In fact, when pathologists are unfamiliar with cytology, it is common to request the assistance of cytopathologists during the evaluation of intraoperative procedures. Key Message: Ventricular tumors of the central nervous system comprise a group of heterogeneous tumors with very different cytologic features. The cytomorphology of these tumors, including rare entities, is often very characteristic, allowing a precise recognition during intraoperative pathologic consultations. Diff-Quik is a valuable staining method that can be used alone or as a complement to hematoxylin and eosin staining. Diff-Quik allows for clear visualization of the overall architecture, cytoplasmic details, and extracellular material.

Endoscopic Transcortical Transventricular Management of Cystic Craniopharyngioma: Outcome Analysis of 32 Cases at a Tertiary Care Center

Background

Microsurgical resection has been considered the gold standard treatment of craniopharyngioma, but lately, it has found less favor due to its morbidity and is being replaced by minimally invasive cyst drainage procedures. We present our experience of transventricular endoscopy and cyst drainage along with its technique and have analyzed its results.

Materials and Methods

Clinical and radiological data of all cystic craniopharyngioma patients treated by transventricular endoscopic cyst drainage and Ommaya placement were retrieved and analyzed.

Results

Thirty-two patients underwent endoscopic cyst drainage during the study period. All patients had immediate clinical and radiological improvement. No significant complications were seen. All patients underwent adjuvant radiotherapy and six patients (18.7%) showed recurrence. Three patients died in the follow-up period.

Conclusions

Endoscopic transcortical transventricular cyst drainage with Ommaya reservoir along with adjuvant radiotherapy is a simple, safe, and effective treatment modality.

One- vs Two-Burr-Hole Technique for Combined Endoscopic Third Ventriculostomy and Pineal Region Biopsy: Volumetric Analysis of Brain at Risk

BACKGROUND

Pineal region tumors are associated with the ventricular system. Endoscopic third ventriculostomy (ETV) is often performed at the same time as tumor biopsy.

OBJECTIVE

To investigate the volume of brain possibly undergoing injury and forniceal stretching during ETV and tumor biopsy.

METHODS

We performed a retrospective review of preoperative magnetic resonance imagings (MRIs) and computed tomography (CTs) of patients with pineal region masses and used volumetric image-guided navigation to simulate a 1-burr-hole vs a 2-burr-hole approach through the brain parenchyma. We compared the volumes of parenchyma and fornix at the risk of injury.

RESULTS

The ideal entry point for ETV using 2 burr holes was a mean ± standard deviation (SD) of 25.8 ± 6 mm from the midline and 11.4 ± 9 mm behind the coronal suture. The ideal entry point using 2 burr holes for tumor biopsy was 25.7 ± 8 mm from the midline and 53.7 ± 14 mm anterior to the coronal suture. With 1 burr hole, the mean ± SD volume of brain parenchyma at risk was 852 ± 440 mm3. The volume of brain parenchyma at risk with 2 burr holes was 2159 ± 474 mm3 (P < .001; paired t-test). The use of 1 burr hole predisposed the fornix to 14 ± 3 mm of possible stretch, which was minimized with the 2-burr-hole approach.

CONCLUSION

Using 1 burr hole for both the ETV and tumor biopsy is less likely to traumatize the brain parenchyma than using 2 burr holes. However, 1 burr hole predisposes the fornix to stretch injury. We recommend tailoring the entry to each patient according to their anatomy rather than using a 1-size-fits-all approach.

Role of endoscopic surgical biopsy in diagnoses of intraventricular/periventricular tumors: review of literature including a monocentric case series

The intra- and periventricular location tumor (IPVT) of a brain remains a hard challenge for the neurosurgeon because of the deep location and eloquent anatomic associations. Due to this high risk of iatrogenic injury, many surgeons elect to perform biopsies of such lesions to establish a diagnosis. On the one hand, stereotaxic needle biopsy (SNB) is a minimally invasive procedure but with a significant risk of complications and a high risk of lack of tissue for molecular analyses for this region [Fukushima in Neurosurgery 2:110-113 (1978)]; on the other hand, the use of endoscopic intraventricular biopsy (EIB) allows for diagnosis with minimal surgical intervention [Iwamoto et al. in Ann Neurol 64(suppl. 6):628-634 (2008)]. IPVTs and related CSF pathway obstructions can be safely and effectively treated with endoscopic techniques. It is not possible to compare EIB with diagnoses made by any other method or with the established treatment. We aim to analyze the accuracy of EIB results by comparing them with results of biopsies performed later, in other methods and thereby evaluating the treatment evolution considering our personal experience. The difficulties and complications encountered are presented and compared with those reported in the literature to obtain the best review possible for this topic. A systematic review of literature was done using MEDLINE, the NIH Library, PubMed, and Google Scholar yielded 1.951 cases for EIB and 1912 for SNB, according to standard systemic review techniques. Review was conducted on 50 studies describing surgical procedures for lesions intra- and para-ventricular. The primary outcome measure was a diagnostic success. We also consider 20 patients with IPVT treated in our department. Clinical characteristics and surgical outcome were evaluated and a systematic review of the literature was performed. Overall, all our biopsies were diagnostic, with a positive histologic sample in 100% of our patients. 8 patients underwent a concurrent endoscopic third ventriculostomy. 4 patients underwent a concurrent ventriculostomy combined with septostomy. For 1 patient was necessary the only septostomy combined with biopsy. Every case has obtained a histological diagnosis. The percentage of complications was very low with only 1 case of post-operative infection and 1 case of hemorrhage. It was impossible to create a specific comparison from literature data of IPVTs between a stereotactic and endoscopic procedure, it presents only the collection of pineal gland tumor [Kelly in Neurosurgery 25(02):185-194 (1989); Quick-Weller in World Neurosurgery 96:124-128 (2016)] or unknown location of the lesion in major review [Marenco-Hillembrand et al. in Front Oncol 8:558 (2018)]. The present study aims to report our experience with the surgical management of IPVTs. The EIB sample yields an accurate histologic diagnosis tumor, with a positive histologic sample in 87, 95% of patients. The choice of the appropriate procedure should consider not only the preference and the experience of the neurosurgeon but also the several other variables as the location. While some periventricular lesions are better approached by endoscopic techniques, others are more suited for stereotactic-guided approaches. The ability to perform an EIB and relieve tumor-associated hydrocephalus by neuroendoscopy is considered to be a benefit of this procedure since this is less invasive than other treatments.

Surgical treatment of hypothalamic hamartomas

Hypothalamic hamartomas are aberrant masses, composed of abnormally distributed neurons and glia. Along endocrine and cognitive symptoms, they may cause epileptic seizures, including the specific gelastic and dacrystic seizures. Surgery is the treatment of drug-resistant hamartoma epilepsy, with associated positive results on endocrine, psychiatric, and cognitive symptoms. Recently, alternatives to open microsurgical treatment have been proposed. We review these techniques and compare their efficacy and safety. Open resection or disconnection of the hamartoma, either through pterional, transcallosal, or transventricular approach, leads to good epileptological control, but its high complication rate, up to 30%, limits its indications. The purely cisternal peduncular forms remain the only indication of open, pterional approach, while other strategies have been developed to overcome the neurological, endocrine, behavioral, or cognitive complications. Laser and radiofrequency thermocoagulation-based disconnection through robot-guided stereo-endoscopy has been proposed as an alternative to open microsurgical resection and stereotactic destruction. The goal is to allow safe and complete disconnection of a possibly complex attachment zone, through a single intraparenchymal trajectory which allows multiple laser or radiofrequency probe trajectory inside the ventricle. The efficacy was high, with 78% of favorable outcome, and the overall complication rate was 8%. It was especially effective in patients with isolated gelastic seizures and pure intraventricular hamartomas. Stereotactic radiosurgery has proved as efficacious and safer than open microsurgery, with around 60% of seizure control and a very low complication rate. Multiple stereotactic thermocoagulation showed very interesting results with 71% of seizure freedom and 2% of permanent complications. Stereotactic laser interstitial thermotherapy (LiTT) seems as effective as open microsurgery (from 76 to 81% of seizure freedom) but causes up to 20% of permanent complications. This technique has however been highly improved by targeting only the epileptogenic onset zone in the hamartoma, as shown on preoperative functional MRI, leading to an improvement of epilepsy control by 45% (92% of seizure freedom) with no postoperative morbidity. All these results suggest that the impact of the surgical procedure does not depend on purely technical matters (laser vs radiofrequency thermocoagulation or stereotactic vs robot-guided stereo-endoscopy) but relies on the understanding of the epileptic network, including inside the hamartoma, the aim being to plan an effective disconnection or lesion of the epileptogenic part while sparing the adjacent functional structures.

Fully Endoscopic Transforaminal-Transchoroidal Approach for Tectal Area Tumor Removal

BACKGROUND

The surgical approaches to lesions located in the tectal area have remained controversial. The essential functions in the surrounding areas and the difficulties in obtaining a good surgical view during tumor removal have made these procedures risky and challenging. Endoscopic transforaminal approaches have been previously described for biopsy and intraventricular tumor removal. However, the endoscopic transforaminal-transchoroidal gross resection technique for such cases has barely been described.

METHODS

The endoscopic entry points and trajectories were planned using preoperative magnetic resonance imaging. Once the endoscope was inside the ventricular system, the angles of work and tumor exposure of the upper posterior part of the third ventricle were carefully evaluated. If the angle of work was insufficient for tumor removal, the choroidal fissure was opened using endoscopic bipolar electrode and dissectors. Tumor removal was performed using an endoscopic ultrasonic aspirator. We have presented a 3-case series of patients affected by tectal tumors that were treated using a fully endoscopic transforaminal-transchoroidal approach.

RESULTS

Total gross resection of the tumors was achieved in 2 patients. Subtotal resection was achieved in the third patient. No major complications had developed in relationship to the procedure. No new cognitive impairment was reported secondary to this technique.

CONCLUSIONS

In our experience, a fully endoscopic transforaminal-transchoroidal approach was a suitable treatment for this complex pathological entity. Opening of the choroidal fissure added an extra angle of work and improved the exposure of the upper posterior part of the third ventricle.

Management of severe intraoperative hemorrhage during intraventricular neuroendoscopic procedures: the dry field technique

OBJECTIVE

The unexpected intraoperative intraventricular hemorrhage is a rare but feared and life-threatening complication in neuroendoscopic procedures because of loss of endoscopic vision. The authors present their experience with the so-called “dry field technique” (DFT) for the management of intraventricular hemorrhages during purely endoscopic procedures. This technique requires the aspiration of the entire intraventricular CSF to achieve clear visualization of the bleeding source.

METHODS

More than 500 neuroendoscopic intraventricular procedures were retrospectively analyzed over the last 24 years for documented severe hemorrhages, which were treated by the application of the DFT.

RESULTS

The technique was required in 6 cases, including tumor resection/biopsy, cyst resection, and intraventricular lavage. Additionally, the technique was applied as part of the planned strategy in 3 cases of endoscopic tumor removal. The hemorrhage was stopped in all cases and no associated postoperative deficits occurred.

CONCLUSIONS

Although severe hemorrhages are rare, the neurosurgeon needs to be aware of them and has to establish strategies for their management. Most hemorrhages can be stopped by constant irrigation and coagulation. In the other rare cases, the DFT is a safe, reliable technique and can be easily incorporated into endoscopic surgery.

Pineal region tumors: Long-term results of endoscopic third ventriculostomy and concurrent tumor biopsy with a single entry approach in a series of 64 cases

OBJECTIVES

Endoscopic third ventriculostomy and concurrent biopsy is increasingly used in management of the pineal region tumors. Our objective was to assess the results of single entry approach to surgically manage the tumors of the pineal region.

PATIENTS AND METHODS

A retrospective study was designed, and a series of 64 consecutive patients (31 male, 33 female) with pineal region tumor undergoing endoscopic third ventriculostomy and concurrent biopsy of the tumor was undertaken.

RESULTS

A total of 64 patients underwent simultaneous endoscopic third ventriculostomy and biopsy of the pineal tumors with a single entry approach. A positive initial diagnosis was established in 97% of patients. 5 patients (7%) required the insertion of an external ventricular drain which was removed in all patients after 72 h but in one case (1%) undergoing permanent VP shunt insertion. The postoperative complications were divided into two transient and permanent complications. The transient complications included intraventricular hemorrhage (18%), seizure (1 to two episodes of seizure) (5%), diabetes insipidus (3%) and meningitis (3%) all were successfully managed. The only permanent complication was memory deficits occurred in one patient (1%). There was no mortality rate in current study.

CONCLUSION

The results of this study support the safety and efficacy of endoscopic third ventriculostomy and concurrent biopsy of the pineal region tumors as a less invasive surgical method associated with low morbidity and mortality rate. Our data demonstrated how simultaneous endoscopic third ventriculostomy and biopsy of the pineal region tumors with a single entry approach can produce favorable results.

Steering a Multi-armed Robotic Sheath Using Eccentric Precurved Tubes

This paper presents a novel continuum robot sheath for use in single-port minimally invasive procedures such as neuroendoscopy in which the sheath is designed to deliver multiple robotic arms. Articulation of the sheath is achieved by using precurved superelastic tubes lining the working channels used for arm delivery. These tubes perform a similar role to push/pull tendons, but can accomplish shape change of the sheath via rotation as well as translation. A kinematic model using Cosserat rod theory is derived which is based on modeling the system as a set of eccentrically aligned precurved tubes constrained along their length by an elastic backbone. The specific case of a two-arm sheath is considered in detail and its relationship to a concentric tube balanced pair is described. Simulation and experiment are used to investigate the concept, map its workspace and to evaluate the kinematic model.

Choroidal artery embolization in the management of cerebrospinal fluid overproduction: case report and review of the literature

Diffuse villous hyperplasia of the choroid plexus (DVHCP) is a rare cause of communicating hydrocephalus. DVHCP may be diagnosed radiographically and through histological evaluation. It may be associated with genetic abnormalities, particularly involving chromosome 9. Due to CSF overproduction, patients with DVHCP often fail management with shunting alone and may require adjuvant interventions. The authors present the case of a child with partial trisomy 9p and delayed diagnosis of hydrocephalus with radiographic evidence of DVHCP who was successfully managed with ventriculoperitoneal shunt (VPS) placement, adjuvant bilateral endoscopic choroid plexus coagulation (CPC), and the novel application of anterior choroidal artery embolization. In addition, a systematic MEDLINE search was conducted using the keywords "diffuse villous hyperplasia," "choroid plexus hypertrophy," and "idiopathic cerebrospinal fluid overproduction." Clinicopathological characteristics and outcomes of the present case were reviewed and compared to those in the literature.A 14-month-old girl with partial trisomy 9p presented with macrocephaly and radiographic evidence of communicating hydrocephalus and DVHCP. Ventriculoperitoneal shunting resulted in distal failure due to inadequate CSF absorption, and ventriculoatrial shunt (VAS) placement was not possible due to multiple cardiac anomalies. Daily CSF production was reduced via endoscopic third ventriculostomy and bilateral CPC, followed by distal choroidal artery embolization, enabling VPS re-internalization. The embolization was complicated by radiographic evidence of an iatrogenic cerebral infarct, but this was clinically occult. Thirty-two additional cases of communicating hydrocephalus due to DVHCP are reported in the literature: 27 pediatric, 3 adult, and 2 postmortem. Genetic abnormalities were noted in 14, with 7 (50%) involving chromosome 9. Twelve patients underwent plexectomy (9 bilateral, 2 unilateral, 1 partial), and 10 underwent CPC (4 bilateral, 3 unilateral, and 3 unspecified), with or without shunting. Eight patients were successfully managed with shunting alone (6 VASs, 2 VPSs), and none underwent arterial embolization.DVHCP is a rare cause of communicating hydrocephalus that may be associated with genetic abnormalities. A thorough review of the literature highlights diagnostic criteria and interventional options involved in managing this cause of CSF overproduction. The present case demonstrates that angiographic confirmation of prominent choroidal arteries may contribute to the diagnosis DVHCP. In addition, embolization of the distal choroidal arteries may be considered as a potential adjuvant treatment in patients for whom conventional treatments have failed or are not feasible.

Ventriculostomy and endoscopic biopsy of pineal mass with hydrocephalus and unexpected definitive diagnosis

A 72-year-old female with no relevant medical history consulted in the emergency room for a two-week history of headache, vomiting and gait disturbance. Head CT scan revealed obstructive hydrocephalus secondary to a pineal mass with compression of the third ventricle. Magnetic Resonance showed another mass located in the right Lushcka foramen. Endoscopic third-ventriculostomy and biopsy of pineal mass were performed. Pathological analysis was consistent with metastasis of carcinoma. Full-body CT scan showed a lung mass related to primary carcinoma. The patient received systemic treatment for metastatic lung cancer. She died two months after diagnosis.

Quantitative Endoscopic Comparison of Contralateral Interhemispheric Transprecuneus and Supracerebellar Transtentorial Transcollateral Sulcus Approaches to the Atrium

OBJECTIVE

The contralateral interhemispheric transprecuneus approach (CITP) and the supracerebellar transtentorial transcollateral sulcus approach (STTC) are 2 novel approaches to access the atrium of the lateral ventricle. We quantitatively compared the 2 approaches.

METHODS

Both approaches were performed in 6 sides of fixed and color-injected cadaver heads. We predefined the 6 targets in the atrium for measurement and standardization of the approaches. Using a navigation system, we quantitatively measured the working distance, cortical transgression, angle of attack, area of exposure, and surgical freedom.

RESULTS

The distances from the craniotomy edge to the posterior pole of the choroid plexus of the CITP (mean ± standard deviation, 67 ± 5.3 mm) and STTC (mean, 57 ± 4.0 mm) differed significantly (P < 0.01). Cortical transgression with the CITP (mean, 27 ± 2.8 mm) was significantly greater than that with the STTC (mean, 21 ± 6.7 mm; P = 0.03). The CITP showed a significantly wider rostrocaudal angle of attack than that with the STTC (P = 0.01). The STTC showed a significantly wider mediolateral angle (P < 0.01). No significant difference was found for surgical freedom of any target except for point E, for which the CITP was larger. The exposure area did not differ significantly between the 2 approaches (P = 0.07).

CONCLUSIONS

Both approaches were feasible for accessing the atrium. The STTC provided a shorter working distance and wider mediolateral angle, CITP provided a wider rostrocaudal angle of attack and better exposure and maneuverability to the anterior and superior atrium. In contrast, the STTC was more favorable for the inferior and posterior regions.

Flexible Neuroendoscopic Diagnosis and Management of Ventricular Tumors: A Retrospective Cohort Study

BACKGROUND

Ventricular tumors (VTs) represent approximately 10% of intracranial lesions and are associated with hydrocephalus in 73.9%-100% of patients. We present our experience using flexible neuroendoscopy as a diagnostic and hydrocephalus-related treatment strategy for paraventricular and intraventricular tumors.

METHODS

This retrospective cohort included 27 pediatric and 21 adult patients with paraventricular or intraventricular tumors treated with flexible neuroendoscopy. Terminally ill patients and patients with incomplete data were excluded.

RESULTS

Male and female patients comprised 52% and 48% of the population, respectively. Mean patient age was 20.45 years (±18.65 SD). The most common tumor location was the thalamic and pineal region. Conclusive pathologic diagnosis was obtained in 40 patients (83.3%); the most common type of tumor was astrocytoma. Hydrocephalus was present in 38 (79.1%) patients, who were treated successfully with endoscopic procedures. There were no major complications.

CONCLUSIONS

Flexible neuroendoscopy is a strategic tool for diagnosis of VTs, especially in patients with associated hydrocephalus and VTs unreachable by other means. Flexible neuroendoscopy has a high rate of definitive diagnosis with low associated complications. More studies evaluating the long-term efficacy of flexible neuroendoscopy for hydrocephalus associated with VTs are needed.

Endoscopic biopsy of intra- and paraventricular brain tumors

Introduction

Selection of the optimal treatment method of intra- and paraventricular tumors often requires histopathological verification that can be obtained by endoscopic biopsy.

Aim

To discuss the usefulness of the method in their own experience.

Material and methods

The results of 32 biopsies carried out during a 15-year period were reviewed retrospectively. All tumors were located supratentorially, 25 of them were intraventricular and 7 paraventricular. In 18 patients the tumor was accompanied by internal hydrocephalus. If the ventricular system was narrow, the biopsy was supported by a neuronavigation system. A rigid neuroendoscope was used. The obtained material was subjected to intraoperative and final histopathological examination.

Results

Viable diagnostic material was obtained from all patients. In 11 patients with tumor of the posterior portion of the third ventricle, cerebrospinal fluid was collected additionally for diagnostic tests. In 9 patients with obstructive hydrocephalus concomitant third ventriculostomy was performed. In 4 patients with tumor of the interventricular foramen, the tumor mass was reduced and in 2 cases septostomy was performed. In 3 (9.4%) cases the histopathological diagnosis was descriptive and did not explain the nature of the lesion. Four biopsies resulted in persistent bleeding, in 3 patients transient memory impairments were observed, and in 1 patient an epileptic seizure occurred. Five patients needed ventriculoperitoneal shunt placement.

Conclusions

Endoscopic biopsy is a safe method to verify the histopathological nature of intra- and paraventricular lesions. It enables sampling of cerebrospinal fluid, reduction of tumor size, and in cases of coexisting obstructive hydrocephalus also third ventriculostomy or septostomy.

Smartphone-assisted minimally invasive neurosurgery

OBJECTIVE

Advances in video and fiber optics since the 1990s have led to the development of several commercially available high-definition neuroendoscopes. This technological improvement, however, has been surpassed by the smartphone revolution. With the increasing integration of smartphone technology into medical care, the introduction of these high-quality computerized communication devices with built-in digital cameras offers new possibilities in neuroendoscopy. The aim of this study was to investigate the usefulness of smartphone-endoscope integration in performing different types of minimally invasive neurosurgery.

METHODS

The authors present a new surgical tool that integrates a smartphone with an endoscope by use of a specially designed adapter, thus eliminating the need for the video system customarily used for endoscopy. The authors used this novel combined system to perform minimally invasive surgery on patients with various neuropathological disorders, including cavernomas, cerebral aneurysms, hydrocephalus, subdural hematomas, contusional hematomas, and spontaneous intracerebral hematomas.

RESULTS

The new endoscopic system featuring smartphone-endoscope integration was used by the authors in the minimally invasive surgical treatment of 42 patients. All procedures were successfully performed, and no complications related to the use of the new method were observed. The quality of the images obtained with the smartphone was high enough to provide adequate information to the neurosurgeons, as smartphone cameras can record images in high definition or 4K resolution. Moreover, because the smartphone screen moves along with the endoscope, surgical mobility was enhanced with the use of this method, facilitating more intuitive use. In fact, this increased mobility was identified as the greatest benefit of the use of the smartphone-endoscope system compared with the use of the neuroendoscope with the standard video set.

CONCLUSIONS

Minimally invasive approaches are the new frontier in neurosurgery, and technological innovation and integration are crucial to ongoing progress in the application of these techniques. The use of smartphones with endoscopes is a safe and efficient new method of performing endoscope-assisted neurosurgery that may increase surgeon mobility and reduce equipment costs.

Modification of the BioMedicus centrifugal pump to provide continuous irrigation for neuroendoscopy: technical note

Continuous irrigation is an important adjunct for successful intraventricular endoscopy, particularly for complex cases. It allows better visualization by washing out blood and debris, improves navigation by expanding the ventricles, and assists with tissue dissection. A method of irrigation delivery using a centrifugal pump designed originally for cardiac surgery is presented. The BioMedicus centrifugal pump has the desirable ability to deliver a continuous laminar flow of fluid that excludes air from the system. A series of modifications to the pump tubing was performed to adapt it to neuroendoscopy. Equipment testing determined flow and pressure responses at various settings and simulated clinical conditions. The pump was then studied clinically in 11 endoscopy cases and eventually used in 310 surgical cases. Modifications of the pump tubing allowed for integration with different endoscopy systems. Constant flow rates were achieved with and without surgical instruments through the working ports. Optimal flow rates ranged between 30 and 100 ml/min depending on endoscope size. Intraoperative use was well tolerated with no permanent morbidity and showed consistent flow rates, minimal air accumulation, and seamless irrigation bag replacement during prolonged surgery. Although the pump is equipped with an internal safety mechanism to protect against pressure buildup when outflow obstructions occur, equipment testing revealed that flow cessation is not instantaneous enough to protect against sudden intracranial pressure elevation. A commonly available cardiac pump system was modified to provide continuous irrigation for intraventricular endoscopy. The system alleviates the problems of inconsistent flow rates, air in the irrigation lines, and delays in changing irrigation bags, thereby optimizing patient safety and surgical efficiency. Safe use of the pump requires good ventricular outflow and, clearly, sound surgical judgment.

Endoscope Holders in Cranial Neurosurgery: Part 2-An International Survey

BACKGROUND

Following a previous systematic review of currently available endoscope holders (EHs), we aspired to detect trends, task-specific preferences, and pitfalls of EH in various cranial neuroendoscopic procedures.

METHODS

A questionnaire was disseminated to members of the International Federation of Neuroendoscopy. The questionnaire evaluated indications and pitfalls of EH in different applications, in particular, differentiating between intraventricular and skull base endoscopy, as well as subcategories of these 2 main fields. Furthermore, interest or involvement in research projects on EH was investigated.

RESULTS

Fifty-two surgeons responded, with a broad geographic distribution represented. Most (54%) do not routinely use EH. Others use holders mainly for intraventricular rather than skull base procedures. Most surgeons (96%) regularly work with a co-surgeon. Reported weaknesses of EH included crude movements, downward drift, loss of depth perception, lack of flexibility, iatrogenic injury, cost, and bulky construct. There is still a lack of consensus on surgical indications. Tumor resections in intraventricular and skull base regions (not small sellar tumors) seem to stand out as good, widely accepted indications.

CONCLUSIONS

Although EH have a role in cranial neuroendoscopy, their use seems limited and their technical features are regarded as suboptimal by most neuroendoscopists. Weaknesses and implications were detected in all application categories (skull base and intraventricular) but may vary slightly. Potentially, separate systems with distinct features may be required for skull base versus intraventricular surgery. There is a need for further evolution of EH, which could lead to a future paradigm shift in their use.

Endoscopic Supracerebellar Transtentorial Approach to Atrium of Lateral Ventricle: Preliminary Surgical and Optical Considerations

OBJECTIVE

We sought to report the operative techniques of the endoscopic supracerebellar transtentorial approach (ESTA) to the atrium of the lateral ventricle, especially focusing on the role of the endoscope and analyzing optically related issues.

METHODS

A retrospective data review was performed on 5 patients with lesions in the atrium of the lateral ventricle undergoing the ESTA. The patients were positioned in the three quarters prone position, and a paramidline linear incision was used. After performing a suboccipital craniotomy extending immediately above the transverse sinus and tentorium incision with precisely neuronavigation, corticotomy in the posterior mediobasal temporal region created a corridor to the tumor. All of the procedures were performed with an endoscope in a pneumatic arm holder. The preoperative and postoperative perimetry test and diffusion tensor imaging fiber tracking of the optic radiations were compared and analyzed.

RESULTS

Three patients had meningiomas, and 2 patients had high-grade gliomas in the atrium. The meningiomas were totally removed, and the gliomas were subtotally resected. One patient with glioblastoma died 2 months later after surgery because of the tumor progression; the remaining 4 patients had a visual field deficit without any other neurologic complications. The endoscope improved the surgical viewing angle, which was restricted by the microscope and slope of the tentorium.

CONCLUSIONS

ESTA is an alternative route to the atrium of the lateral ventricle. However, the collateral sulcus, which is highly relied on in neuronavigation, is illegible in the limited area. And the visual field deficit remains the primary challenge with this approach.

Keyhole approach in the neuroendoscopic treatment for hydrocephalus

The aim of the study was to explore keyhole approach and dura suture in the neuroendoscopic treatment for hydrocephalus.Twelve cases of hydrocephalus patients who were treated with neuroendoscope by this approach were analyzed retrospectively from April 2015 to April 2016 in our department. The basic steps of this procedure was using drill and milling cutter to form a small bone flap instead of burr hole, and then making a cruciate incision on the dura. After endoscopic third ventriculostomy or endoscopic third ventriculostomy + ventriculocystostomy finished, dura was sutured and the bone flap was reset.All 12 patients could suture dura effectively, and no cerebrospinal fluid leak and subcutaneous cerebrospinal fluid collection happened; symptoms of hydrocephalus were also improved. Moreover, during the operation, we found this approach could suspend dura, and avoid the cerebral sulcus and cortical coarse vein effectively, which could reduce the risk of intracranial hemorrhage. In addition, we found this approach could increase the reachable range of the neuroendoscope significantly.Keyhole approach can suture dura and avoid the cerebral sulcus and cortical coarse vein effectively, increase the indications, and reduce complications of neuroendoscope. So, this approach has clinical values and can be used in hydrocephalus.

Endoscopic Reconstruction of CSF Pathways in Ventricular Tumors

Neuroendoscopy is now considered to be a minimally invasive surgical approach for expanding lesions bulging into the ventricle, and it is also considered to be a relevant tool for performing biopsy procedures, fenestration of cystic walls, or for performing tumor removal in selected cases. Furthermore, the use of neuroimaging and the accurate follow-up of brain tumor patients have allowed the documentation of tumoral and pseudotumoral cystic areas that cause the obstruction of cerebrospinal fluid (CSF) pathways. Neuroendoscopic procedures enable the fenestration of cystic lesions, in addition to enabling third ventriculostomy or septostomy to restore CSF pathways. We analyze our experience regarding 77 patients affected by brain tumors arising from the wall of the third or lateral ventricle. In all cases hydrocephalus or obstruction of CSF flow was present. With an endoscopic technique, septostomy, cystostomy, endoscopic third ventriculostomy (ETV), and tumor resection were performed to control intracranial hypertension.ETV was performed in 53 patients with noncommunicating hydrocephalus. In 4 patients with low-grade astrocytoma ETV was definitely the only surgical treatment. In 12 cystic tumors, cystostomy and marsupialization into the ventricle solved a relevant mass effect with clinical intracranial hypertension syndrome. In 10 patients, neuroendoscopic relief of CSF pathways was possible by performing septostomy with the implantation of an Ommaya reservoir or one-catheter shunt. In 5 colloid cysts and 2 cystic craniopharyngiomas, removal was possible by restoring CSF flow without other procedures. After intracranial hypertension control, in 13 malignant gliomas and 5 leptomeningeal metastases, the patients' quality of life improved sufficiently to provide for tumor adjuvant therapy.In this series, endoscopy, due to its minimally invasive characteristics and reduced complications, was found to be safe and effective, without any relevant postoperative morbidity, gained by avoiding major surgical approaches.Based on these results and on the increasing number of series described in the literature, we believe that endoscopic techniques should be considered a selected approach for treating CSF obstructions caused by para-intraventricular tumors. The result of using neuroendoscopy is the reconstruction of CSF pathways that bypass the tumor occlusion. This surgical procedure is not only limited to the relief of noncommunicating hydrocephalus, but it is also useful for tumor removal or biopsies and the evacuation of cystic lesions. In patients affected by malignant tumors, neuroendoscopy can be performed to control intracranial hypertension before the patients start adjuvant chemotherapy or radiotherapy.

Recent technological advances in pediatric brain tumor surgery

X-rays and ventriculograms were the first imaging modalities used to localize intracranial lesions including brain tumors as far back as the 1880s. Subsequent advances in preoperative radiological localization included computed tomography (CT; 1971) and MRI (1977). Since then, other imaging modalities have been developed for clinical application although none as pivotal as CT and MRI. Intraoperative technological advances include the microscope, which has allowed precise surgery under magnification and improved lighting, and the endoscope, which has improved the treatment of hydrocephalus and allowed biopsy and complete resection of intraventricular, pituitary and pineal region tumors through a minimally invasive approach. Neuronavigation, intraoperative MRI, CT and ultrasound have increased the ability of the neurosurgeon to perform safe and maximal tumor resection. This may be facilitated by the use of fluorescing agents, which help define the tumor margin, and intraoperative neurophysiological monitoring, which helps identify and protect eloquent brain.

Conversion technique from neuroendoscopy to microsurgery in ventricular tumors: Technical note

BACKGROUND

Ventricular tumors represent a major neurosurgical challenge, making endoscopic approach an invaluable tool as it gained importance due to technological advances. Nevertheless, the method is not exempt of risk and limitations, sometimes requiring an open surgery. Thus, initial measurements must be adopted in order to simplify an eventual need for conversion to open craniotomy.

METHODS

Here, we describe a series of 6 patients with ventricular tumors approached by neuroendoscopy where the conversion to microsurgery turned out to be necessary. Patients' average age was 59.5 years (39-75 years). Average tumoral size was 17.8 mm (15-21 mm). There were 2 cases of lateral ventricle subependymoma and 4 cases of third ventricle colloid cysts. A standard surgical incision was performed in the coronal direction, allowing lateral expansion to 10 cm. Moreover, the endoscopic burr hole was enlarged to a 5 cm craniotomy. A small enlargement of the endoscopic cortical access was performed to gain a transcortical microsurgical corridor to the ventricular cavity. The need for conversion arose due to high consistency of the tumor (3 cases), technical problems (2 cases), and cortical collapse (1 case).

RESULTS

There was one case of cerebrospinal fluid fistula and infection and one case of transitory memory disturbance. In both the cases, we obtained a complete functional recovery. Clinical and radiological follow-up showed total tumor removal with no recurrences.

CONCLUSIONS

The technique herein described was easy to perform, promptly bypassed the endoscopic limitations, and gathered excellent surgical results. The possibility of adapting the method to other tumor locations may be considered.

Neuroendoscopy via an Extremely Narrow Foramen of Monro: A Case Report

Herein, safe and reliable neuroendoscopic biopsy via an extremely narrow foramen of Monro (ENFM) for a non-hydrocephalic patient with hypothalamic and pineal region tumors was successfully applied. A 17-year-old boy presented with hypothalamic manifestations attributed to hypothalamic and pineal region tumors. Small ventricles were seen. Intraoperatively, to advance different diameter steerable fiberscopes via ENFM, the third ventricle was flushed to induce a moment increase in the intraventricular pressure with subsequent dilatation of FM. Postoperative course was uneventful. Histopathological studies revealed a yolk sac tumor. Adjuvant therapy was applied. Follow-up neuroimaging disclosed marvellous improvement of the condition. His symptoms gradually improved.

Pediatric intraventricular arachnoid cysts in the body of lateral ventricle: surgical outcome and its embryologic background

PURPOSE

The aim of this study is for the surgical treatment and outcome of the endoscopic fenestration of the arachnoid cyst located in the ventricular body to trigone in the pediatric population. Special concern was paid for the developmental origin of the intraventricular cysts estimated from the postoperative follow-up neuroimagings.

PATIENTS AND METHODS

Between July 2002 and June 2015, we performed endoscopic and partly CT/MRI navigated fenestrations of intraventricular arachnoid cysts located at the body to trigone of the lateral ventricle in ten pediatric patients aged 2 months to 5 years. Based on the long axis of the cyst, we have opted for two surgical approaches: anterior approach via burr hole at Kocher's point and posterior approach via burr hole at the posterior occipital region. Fenestration was performed based on the intraoperative findings, either ventriculocystostomy, ventriculocystoventriculostomy, or ventriculocystocisternostomy.

RESULTS

Intraventricular arachnoid cysts located in the body-trigone region showed a favorable outcome after endoscopic fenestration. All of the cysts shrank postoperatively. Follow-up neuroimagings taken between 6 and 126 months after surgery strongly suggested its relationship with the midline cisterns. Of our ten cases, eight were suggestive for originating from the velum interpositum cistern while two seemed to root from the quadrigeminal cistern.

CONCLUSION

In the present study, we found that endoscopic fenestration of intraventricular arachnoid cysts in the body to trigone is a safe procedure with a satisfactory outcome. In our limited experience, there are two anatomic backgrounds; velum interpositum cistern and quadrigeminal cistern. Differentiation can be possible by neuroimagings, especially those obtained after surgery.

Endoscope-assisted resection of cavernous angioma at the foramen of Monro: a case report

INTRODUCTION

Intraventricular cavernous angiomas are rare pathological entities, and those located at the foramen of Monro are even rarer. We herein present a case of cavernous angioma at the foramen of Monro that was successfully treated by neuroendoscope-assisted surgical removal, and review the relevant literature.

CASE PRESENTATION

A 65-year-old woman had experienced headache and vomiting for 10 days before admission to another hospital. Magnetic resonance imaging (MRI) showed a mass at the foramen of Monro, and obstructive hydrocephalus of both lateral ventricles. The patient was then referred to our hospital. Neurological examination on admission to our hospital showed memory disturbance (Mini-Mental State Examination 20/30) and wide-based gait. A cavernous angioma at the foramen of Monro was diagnosed based on the typical popcorn-like appearance of the lesion on MRI. The lesion was completely removed by neuroendoscope-assisted transcortical surgery with the Viewsite Brain Access System (Vycor Medical Inc., Boca Raton, FL), leading to a reduction in the size of the ventricles. The resected mass was histologically confirmed to be cavernous angioma. The patient's symptoms resolved immediately and there were no postoperative complications.

CONCLUSION

Minimally invasive neuroendoscope-assisted surgery was used to successfully treat a cavernous angioma at the foramen of Monro.

Endoscopic fenestration of intraventricular cerebrospinal fluid cysts: the contralateral approach

OBJECT

The endoscopic fenestration of intraventricular CSF cysts has evolved into a well-accepted treatment modality. However, definition of the optimal trajectory for endoscopic fenestration may be difficult. Distorted ventricular anatomy and poor visibility within the cyst due to its contents can make endoscopic fenestration challenging if approached from the ipsilateral side. In addition, transcortical approaches can theoretically cause injury to eloquent cortex, particularly in patients with dominant-sided lesions. The aim of this study was to examine the value of the contralateral transcortical transventricular approach in patients with dominant-sided ventricular cysts.

METHODS

During a 5-year period between 2007 and 2011, 31 patients with intraventricular CSF cysts underwent surgery by the senior author (R.R.). Fourteen of these patients had cysts located on the dominant side. An image-guided endoscopic cyst fenestration via the contralateral transcortical transventricular approach was performed in 11 patients. A retrospective chart review was performed in all these patients to extract data on clinical presentation, operative technique, and surgical outcome.

RESULTS

The most common presenting symptom was headache, followed by memory deficits and cognitive deterioration. In all cases CSF cysts were space occupying, with associated obstructive hydrocephalus in 8 patients. Image-guided endoscopic fenestration was successfully performed in all cases, with septum pellucidotomy necessary in 6 cases, and endoscopic third ventriculostomy in 1 case for additional aqueductal occlusion. Postoperative clinical outcome was excellent, with no associated permanent neurological or neuropsychological morbidity. No recurrent cysts were observed over a mean follow-up period of 2 years and 3 months.

CONCLUSIONS

The contralateral approach to ventricular cysts can achieve excellent surgical outcomes while minimizing approach-related trauma to the dominant hemisphere. Careful case selection is essential to ensure that the contralateral endoscopic trajectory is the best possible exposure for sufficient cyst fenestration and restoration of CSF circulation.