Combined intraoperative magnetic resonance imaging and navigated neuroendoscopy in children with multicompartmental hydrocephalus and complex cysts: a feasibility study

Low-Field Portable MR Imaging to Evaluate Ventricular Volumes: A Single-Center Retrospective Study

This study assesses the efficacy of low-field portable MR imaging in measuring ventricular volumes in the pediatric population in the hospital setting. We compared portable and standard of care MR images from the same patient. The estimated ventricular volumes had excellent agreement with a mean bias of 2.06% by Bland-Altman analysis and a correlation of 0.99. From this initial data set, our results suggest that low-field, portable MR imaging is a promising technique for imaging and quantifying ventricular volumes.

Tailored Concept for Accurate Neuroendoscopy: A Comparative Retrospective Single-Center Study on Image-Guided Neuroendoscopic Procedures

OBJECTIVE

Precise planning and execution is key for neuroendoscopic interventions, which can be based on different available aiding technologies. The aim of this retrospective study is to report a case-based use of guided neuroendoscopy and to develop a stratification algorithm for the available technologies.

METHODS

We reviewed consecutive neuroendoscopic cases performed at our center from 2016 to 2018. We distinguished between patients receiving a new burr hole (group A) and those with a preexisting burr hole (group B). Case-specific technical requirements for procedure planning and execution, complication rate, surgical outcome, and possible subsequent surgery were evaluated. From this experience, a stratification system was developed to tailor the available guiding technologies.

RESULTS

A total of 309 neuroendoscopic interventions in 243 patients were included in the present study. The cases included hydrocephalic (81.6%) and nonhydrocephalic (18.4%) conditions. The interventions were supported by coordinate-based (group A, n = 49; group B, n = 67), guide-based (group A, n = 42; group B, n = 0), ultrasound-guided (group A, n = 50; group B, n = 7), or navigated augmented reality-guided (group A, n = 85; group B, n = 9) techniques. The overall complication rate was 4.5%. Stratified by the surgical indication, fontanel status, entry point localization, presence of a preexisting burr hole, ventricular size, and number of targets, an approach toward image-guided neuroendoscopy is suggested.

CONCLUSIONS

Planning and technical guidance is essential in neuroendoscopic procedures. The stratified decision-making algorithm for different available technologies aims to achieve lower cost and time consumption, which was found to be safe and efficient. Further investigations are warranted to deliver solid data on procedure efficiency.

Role of Endoscopy in Treatment of Complex Hydrocephalus in Children

Complex hydrocephalus or loculated hydrocephalus is a challenging problem in the field of pediatric neurosurgery. Early diagnosis and treatment are paramount in order to ensure success of treatment. Therefore, alertness is required among pediatricians who are dealing with premature children and children having meningitis and/or intraventricular hemorrhage. Disproportionate hydrocephalic changes in CT scan of the brain are suspicious, whereas gadolinium-enhanced multiplanar MR imaging (axial, sagittal, and coronal) is the best diagnostic modality. The definitive treatment is surgical, yet the approach remains a matter of debate. Cyst fenestration, communicating the isolated compartments together and with the ventricular system, is the main strategy of treatment. Cyst fenestration can be performed through either microsurgery or endoscopy, in order to improve the hydrocephalus, decrease number of shunts, and reduce shunt revision rates. However, the endoscopic procedure has an advantage over microsurgery of being simple and minimally invasive. It is evident that uniloculated hydrocephalus carries better prognosis than multiloculated hydrocephalus; this can be attributed to the initial pathological disease contributing to the ventricular compartmentalization. Because of the bad prognosis in multiloculated hydrocephalus, and because there are few numbers of patients available in any given center, a multicentric prospective study with long-term follow-up evaluating the results of outcome and quality of life is warranted.

Surgical treatment of post-infectious hydrocephalus in infants

The management of post-infective hydrocephalus in infants remains a challenging task for the pediatric neurosurgeon. The decision-making curve is often complex in that appropriate temporizing measures need to be implemented to properly clear any infection within the CSF before any decision can be made regarding a permanent solution. The etiology differs at varying stages of neonatal development, and the weight of the child, skin fragility, and relevant surgical treatment options are often important limiting factors. Deciding on the optimal treatment option involves assessing the etiology, age, and clinical and radiological features of the individual case and selecting the most appropriate surgical option.

Navigated neuroendoscopy combined with intraoperative magnetic resonance cysternography for treatment of arachnoid cysts

Endoscopic cystocysternostomy or cystoventriculostomy is the treatment of choice in patients with symptomatic intracranial arachnoid cysts. There are no objective diagnostic tests for reliable intraoperative evaluation of the effectiveness of performed stomies. The aim of this prospective open-label study is to demonstrate for the first time the usefulness of intraoperative cysternography performed with the low-field 0.15-T magnetic resonance imager Polestar N20 during endoscopic cysternostomies. The study was performed in patients operated for middle fossa arachnoid cysts (n = 10), suprasellar cysts (n = 4), paraventricular or intraventricular cysts (n = 6), and a pineal cyst (n = 1). The operations were performed with use of a navigated neuroendoscope. Intraoperative magnetic resonance (iMR) cysternography was performed before and after the cystostomy. In each case, iMR cysternography was safe and could show clearly the cyst morphology and the effectiveness of performed endoscopic cystostomies. In six cases, iMR cysternography had a significant influence of the surgical decision (p = 0.027). The rate of inconsistency between the intraoperative observations and iMR imaging–based findings was 29%. A good contrast flow through the fenestrated cyst walls correlated with a good long-term clinical outcome (ρ = 0.54, p < 0.05) and good long-term radiological outcome (ρ = 0.72, p < 0.05). Intraoperative low-field MR cysternography is a safe and reliable method for assessment of the efficacy of performed endoscopic cystostomies and has significant influence on the surgical decision. It may be reliably used for prediction of the long-term clinical and radiological outcome.

Treatment of multi-loculated hydrocephalus using endoscopic cyst fenestration and endoscopic guided VP shunt insertion

OBJECTIVE

To evaluate the role of endoscopic cyst fenestration and endoscopic guided VP shunt insertion in multi-loculated hydrocephalus in children.

METHOD

A retrospective analysis was performed on 20 patients with multi-loculated hydrocephalus who underwent endoscopic cyst fenestration (ECF) alone or in combination with VP shunt revision or insertion between August 2014 and December 2016 with the extended follow-up period to December 2017.

RESULTS

Thirty-one ECFs were performed: ECF alone, 10 operations in 8 cases, and 21 ECFs with shunt insertion in 12 cases. Eighteen of 20 patients required a VP shunt, 7 cases required multiple shunts. All patients with a previous shunt remained shunt dependent; and 6 cases with no prior shunt underwent endoscopic guided ventricular catheter insertion after ECF; only 2 cases did not require a shunt after ECF. The rate of repeated ECFs was 0.25 operations/year and the shunt revision rate was 0.11 operations/year. VP shunt or cystoperitoneal shunt without repeat ECF was used in 7 cases (35%). Mean duration between operations was 71 days in repeated ECF and 16 days in added-on shunt. The most common cause of re-operations was new formation of intraventricular fibrosis or compartmentalization causing ventricular catheter blockage.

CONCLUSION

Endoscopic cyst fenestration and endoscopic assisted VP shunt insertion minimize shunt complications in multi-loculated hydrocephalus. Shunt independence is unusual.

Infected multilocular hydrocephalus treated by rigid and flexible endoscopes with electromagnetic-guided neuronavigation: a case report

BACKGROUND

Endoscopic surgery assisted by a navigation system has greatly aided treatment of infected multilocular hydrocephalus, especially in children.

CASE REPORT

We describe a 2-year-old boy with multilocular hydrocephalus caused by repeated shunt infection, presenting with fever and vomiting. Magnetic resonance images (MRI) showed extraventricular cysts and severe ventricular deformity. There were three ventriculoperitoneal shunts and one residual ventricular catheter. With a flexible endoscope, we fenestrated the wall of extraventricular cysts and removed the residual catheter. We then used a rigid endoscope to fenestrate ventricular components. Both procedures were guided by electromagnetic (EM) navigation, and hydrocephalus was controlled with one ventricular catheter.

CONCLUSION

We have successfully treated a case suffered from infected multilocular hydrocephalus in infants using rigid and flexible endoscopes combined with EM navigation.

The view through the ventricle catheter - The new ShuntScope for the therapy of pediatric hydrocephalus

PURPOSE

Correct placement of the ventricle catheter directly influences the function of cerebral shunt systems. The incidence of proximal catheter misplacement reaches up to 45%. To avoid misplacements and revisions a new intra-catheter endoscope for precise ventricle catheter placement in children was evaluated.

METHODS

The semi-rigid ShuntScope (Karl Storz GmbH & Co.KG, Tuttlingen, Germany) with an outer diameter of 1.0 mm and an image resolution of 10,000 pixels was used in a series of 27 children and adolescents (18 males, 9 females, age range 2 months-18 years). Indications included catheter placement in aqueductal stenting (n = 4), first time shunt placement (n = 5), burr hole reservoir insertion (n = 4), catheter placement after endoscopic procedures (n = 7) and revision surgery of the ventricle catheter (n = 7).

RESULTS

ShuntScope guided precise catheter placement was achieved in 26 of 27 patients. In one case of aqueductal stenting, the procedure had to be abandoned. One single wound healing problem was noted as a complications. Intraventricular image quality was always sufficient to recognize the anatomical structures. In case of catheter removal, it was helpful to identify adherent vessels or membranes. Penetration of small adhesions or thin membranes was feasible. Postoperative imaging studies demonstrated catheter tip placements analogous to the intraoperative findings.

CONCLUSIONS

Misplacements of shunt catheters are completely avoidable with the presented intra-catheter technique including slit ventricles or even aqueductal stenting. Potential complications can be avoided during revision surgery. The implementation of the ShuntScope is recommended in pediatric neurosurgery.

Intra-catheter endoscopy for various shunting procedures-a retrospective analysis on surgical practicability, catheter placement, and failure rates

BACKGROUND

The long-term function of a cerebral shunt is directly influenced by the placement of the ventricle catheter. In this work, an intra-luminal endoscope for best possible catheter positioning was used. Practicability, postoperative imaging, and shunt failure rates were retrospectively evaluated.

METHODS

Between January 2012 and June 2016, an intra-catheter endoscope was applied in 71 procedures. Endoscopic technique was used for catheter placement in first-time shunting or cerebrospinal fluid reservoir insertion (n = 38), revision surgery in proximal shunt failure (n = 13), and various intraventricular stenting procedures (n = 20). Catheter positioning was graded on postoperative imaging using a four-point scale. All patients were regularly followed up (mean, 31.6 months) to recognize shunt failures.

RESULTS

Endoscopic application could be completed as intended in 68 of 71 procedures. Postoperative imaging could exclude complete misplacement of all catheters, but optimal positioning was only achieved in 64.7% (44/68 cases). Four catheters had to be revised due to malfunction (failure rate, 5.8%). Another five catheters had to be removed due to infectious complications or wound-healing disorders. Direct correlations between catheter complications and suboptimal catheter positioning were not seen. Slit or distorted ventricles also did not prove to be a risk factor for the observed complications.

CONCLUSIONS

Versatile application possibilities of the intra-catheter endoscope reflect the advantages of the technique. Independent of the performed procedure, unintended positionings or even complete catheter misplacements could be avoided. However, in more than one-third of all cases, suboptimal catheter placements became obvious. Interestingly, negative influences on later shunt failures were not seen.

Augmented reality in intraventricular neuroendoscopy

BACKGROUND

Individual planning of the entry point and the use of navigation has become more relevant in intraventricular neuroendoscopy. Navigated neuroendoscopic solutions are continuously improving.

OBJECTIVE

We describe experimentally measured accuracy and our first experience with augmented reality-enhanced navigated neuroendoscopy for intraventricular pathologies.

PATIENTS AND METHODS

Augmented reality-enhanced navigated endoscopy was tested for accuracy in an experimental setting. Therefore, a 3D-printed head model with a right parietal lesion was scanned with a thin-sliced computer tomography. Segmentation of the tumor lesion was performed using Scopis NovaPlan navigation software. An optical reference matrix is used to register the neuroendoscope's geometry and its field of view. The pre-planned ROI and trajectory are superimposed in the endoscopic image. The accuracy of the superimposed contour fitting on endoscopically visualized lesion was acquired by measuring the deviation of both midpoints to one another. The technique was subsequently used in 29 cases with CSF circulation pathologies. Navigation planning included defining the entry points, regions of interests and trajectories, superimposed as augmented reality on the endoscopic video screen during intervention. Patients were evaluated for postoperative imaging, reoperations, and possible complications.

RESULTS

The experimental setup revealed a deviation of the ROI's midpoint from the real target by 1.2 ± 0.4 mm. The clinical study included 18 cyst fenestrations, ten biopsies, seven endoscopic third ventriculostomies, six stent placements, and two shunt implantations, being eventually combined in some patients. In cases of cyst fenestrations postoperatively, the cyst volume was significantly reduced in all patients by mean of 47%. In biopsies, the diagnostic yield was 100%. Reoperations during a follow-up period of 11.4 ± 10.2 months were necessary in two cases. Complications included one postoperative hygroma and one insufficient fenestration.

CONCLUSIONS

Augmented reality-navigated neuroendoscopy is accurate and feasible to use in clinical application. By integrating relevant planning information directly into the endoscope's field of view, safety and efficacy for intraventricular neuroendoscopic surgery may be improved.

A multiport MR-compatible neuroendoscope: spanning the gap between rigid and flexible scopes

OBJECTIVE Rigid endoscopes enable minimally invasive access to the ventricular system; however, the operative field is limited to the instrument tip, necessitating rotation of the entire instrument and causing consequent tissue compression while reaching around corners. Although flexible endoscopes offer tip steerability to address this limitation, they are more difficult to control and provide fewer and smaller working channels. A middle ground between these instruments-a rigid endoscope that possesses multiple instrument ports (for example, one at the tip and one on the side)-is proposed in this article, and a prototype device is evaluated in the context of a third ventricular colloid cyst resection combined with septostomy. METHODS A prototype neuroendoscope was designed and fabricated to include 2 optical ports, one located at the instrument tip and one located laterally. Each optical port includes its own complementary metal-oxide semiconductor (CMOS) chip camera, light-emitting diode (LED) illumination, and working channels. The tip port incorporates a clear silicone optical window that provides 2 additional features. First, for enhanced safety during tool insertion, instruments can be initially seen inside the window before they extend from the scope tip. Second, the compliant tip can be pressed against tissue to enable visualization even in a blood-filled field. These capabilities were tested in fresh porcine brains. The image quality of the multiport endoscope was evaluated using test targets positioned at clinically relevant distances from each imaging port, comparing it with those of clinical rigid and flexible neuroendoscopes. Human cadaver testing was used to demonstrate third ventricular colloid cyst phantom resection through the tip port and a septostomy performed through the lateral port. To extend its utility in the treatment of periventricular tumors using MR-guided laser therapy, the device was designed to be MR compatible. Its functionality and compatibility inside a 3-T clinical scanner were also tested in a brain from a freshly euthanized female pig. RESULTS Testing in porcine brains confirmed the multiport endoscope's ability to visualize tissue in a blood-filled field and to operate inside a 3-T MRI scanner. Cadaver testing confirmed the device's utility in operating through both of its ports and performing combined third ventricular colloid cyst resection and septostomy with an endoscope rotation of less than 5°. CONCLUSIONS The proposed design provides freedom in selecting both the number and orientation of imaging and instrument ports, which can be customized for each ventricular pathological entity. The lightweight, easily manipulated device can provide added steerability while reducing the potential for the serious brain distortion that happens with rigid endoscope navigation. This capability would be particularly valuable in treating hydrocephalus, both primary and secondary (due to tumors, cysts, and so forth). Magnetic resonance compatibility can aid in endoscope-assisted ventricular aqueductal plasty and stenting, the management of multiloculated complex hydrocephalus, and postinflammatory hydrocephalus in which scarring obscures the ventricular anatomy.

The benefits of navigated neuroendoscopy in children with multiloculated hydrocephalus

Context:

Multiloculated hydrocephalus remains one of the most challenging neurosurgical problems. In this study, we use frameless navigation during endoscopic interventions to improve the efficiency of operations.

Subjects and Methods:

Nine navigated endoscopic procedures were performed in 8 children with various forms of multiloculated hydrocephalus from March 2013 to June 2014. Preoperatively, the optimal entry point for fenestration of several cysts was determined on the basis of magnetic resonance data. During surgery, rigid endoscope was registered in neuronavigation system for making the connection between separated ventricles and cysts. The final stage of the operation was to conduct a stent through the working channel of the endoscope for implantation of a shunt.

Results:

Number of compartments interconnected by an operation ranged from 3 to 5. Seven interventions were performed simultaneously with the shunt implantation. The follow-up period ranged from 9 to 15 months. The clinical improvement as a result of the operation was achieved in all children. The follow-up included clinical examination and evaluation of magnetic resonance imaging. Additional surgery was necessary in two patients: The first 5 months later, the second 1-year after endoscopic intervention.

Conclusion:

Application of frameless navigated neuroendoscopy makes this kind of operations the most efficient and safe for the patient.

Neurosurgical tools to extend tumor resection in pediatric hemispheric low-grade gliomas: iMRI

INTRODUCTION

The treatment of low-grade gliomas (LGGs) in pediatric age is still controversial. However, most authors report longer life expectancy in case of completely removed cerebral gliomas. Intraoperative magnetic resonance imaging (iMRI) is increasingly utilized in the surgical management of intra-axial tumor in adults following the demonstration of its effectiveness. In this article, we analyze the management of LGG using iMRI focusing on its impact on resection rate and its limits in the pediatric population.

METHODS

We performed review of the literature regarding the treatment of LGG using iMRI focusing on its impact on resection rate and its limits in the pediatric population. Some exemplary cases are also described.

RESULTS

Intraoperative MRI allowed extension of tumor resection after the depiction of residual tumor at the intraoperative imaging control from 21 to 52 % of the cases in the published series. Moreover, the early reoperation rate was significantly lower when compared with the population treated without this tool (0 % vs 7-14 %). Some technical difficulties have been described in literature regarding the use of iMRI in the pediatric population especially for positioning due to the structure of the headrest coil designed for adult patients.

CONCLUSION

The analysis of the literature and our own experience with iMRI in children indicates significant advantages in the resection of LGG offered by the technique. All these advantages are obtained without elongation of the surgical times or increased risk for complications, namely infection. The main limit for a wider diffusion of iMRI for the pediatric neurosurgical center is the cost required, for acquisition of the system, especially for high-field magnet, and the environmental and organizational changes necessary for its use.

[The use of frameless navigation during endoscopic interventions in children with multilocular hydrocephalus]

INTRODUCTION

The use of the endoscopic technique largely improves treatment outcomes in patients with multilocular hydrocephalus. However, impaired anatomy and the lack of usual landmarks often cause problems in planning and intraoperative identification of changed structures. The use of frameless navigation during endoscopic interventions can significantly facilitate surgeon tasks and increases the efficacy of surgery. During surgery, the neuronavigation system visualizes a rigid endoscope that interconnects separated ventricles and cysts. Surgery can be completed with guiding a stent through an operating channel of the endoscope and implanting a shunt system.

MATERIAL AND METHODS

Ten children underwent 11 endoscopic interventions using frameless intraoperative navigation at our clinic in 2013-2014. The number of surgically interconnected compartments ranged from 3 to 5. Simultaneous placement of a shunt system was performed in 8 of 11 interventions.

RESULTS

Clinical improvement as a result of the operation was achieved in all children. 2 patients underwent re-operations 5 months and 1 year after endoscopic intervention.

CONCLUSION

Thus, the use of frameless navigation during endoscopic interventions makes their implementation most efficient and safe for the patient.

Neuroendoscopy Followed by Radiotherapy in Cystic Craniopharyngiomas--a Long-Term Follow-Up

BACKGROUND

Treatment of cystic craniopharyngiomas is often complicated because of adherence of craniopharyngiomas to adjacent brain structures. A strategy involving neuroendoscopic procedures followed by stereotactic radiotherapy is less invasive, avoiding brain damage. However, long-term follow-up of this strategy has not been investigated in depth.

METHODS

Cystic craniopharyngiomas in 9 patients were treated with neuroendoscopic cyst aspiration and fenestration, followed by fractionated stereotactic radiotherapy (FSRT). The neuroendoscopic procedure focused on widening of cyst fenestration and extensive irrigation of the cyst contents. FSRT was performed using 6 fixed beams, an 8-mm margin to cover the gross tumor volume with a 95% isodose line, and a target delivered dose of 50.4 Gy in 28 fractions.

RESULTS

The median follow-up period was 72.9 months. Tumor control was achieved in 8 of 9 patients (88.9%). Marked tumor volume reduction was obtained with the neuroendoscopic procedure alone (26.1%) at 6 months (20.4%), 1 year (11.0%), and 2 years (3.1%). One recurrent case showed multilobulated cysts, and a second surgery was required 1 year after the treatment. Clinical symptoms such as headache and visual disruption were rapidly alleviated after the neuroendoscopic procedure. No new visual disturbances, endocrinopathy, or hypothalamic dysfunction was observed during follow up.

CONCLUSIONS

Neuroendoscopic cyst aspiration and fenestration followed by FSRT is a less invasive, powerful strategy for treating adult cystic craniopharyngiomas.

Intraoperative MRI in pediatric neurosurgery-an update

Since the advent of intraoperative magnetic resonance imaging (ioMRI) at the Brigham and Women's Hospital in 1994, ioMRI has spread widely and in many different forms. This article traces the developmental history of ioMRI and reviews the relevant literature regarding it's effectiveness in pediatric neurosurgery. While of considerable expense, current trends in healthcare essentially mandate the use of ioMRI in a growing number of cases.

[First intraoperative magnetic resonance imaging in a Spanish hospital of the public healthcare system: initial experience, feasibility and difficulties in our environment]

OBJECTIVE

Intraoperative MRI is considered the gold standard among all intraoperative imaging technologies currently available. Its main indication is in the intraoperative detection of residual disease during tumour resections. We present our initial experience with the first intraoperative low-field MRI in a Spanish hospital of the public healthcare system. We evaluate its usefulness and accuracy to detect residual tumours and compare its intraoperative results with images obtained postoperatively using conventional high-field devices.

MATERIAL AND METHODS

We retrospectively reviewed the first 21 patients operated on the aid of this technology. Maximal safe resection was the surgical goal in all cases. Surgeries were performed using conventional instrumentation and the required assistance in each case.

RESULTS

The mean number of intraoperative studies was 2.3 per procedure (range: 2 to 4). Intraoperative studies proved that the surgical goal had been achieved in 15 patients (71.4%), and detected residual tumour in 6 cases (28.5%). After comparing the last intraoperative image and the postoperative study, 2 cases (9.5%) were considered as "false negatives".

CONCLUSIONS

Intraoperative MRI is a safe, reliable and useful tool for guided resection of brain tumours. Low-field devices provide images of sufficient quality at a lower cost; therefore their universalisation seems feasible.

Selective use of intra-catheter endoscopic-assisted ventricular catheter placement: indications and outcome

PURPOSE

In a previous well-controlled study, routine endoscopic-guided placement of ventricular catheters did not seem to decrease the rate of shunt failure or proximal shunt malfunction. Since this study was published, this technique does not seem to gain much acceptance. However, in selected cases, it may assist in accuracy and safety. We therefore have analyzed our experience with selective intra-catheter endoscopic use for ventricular hardware placement.

METHODS

We retrospectively collected clinical and radiological data on all children undergoing intra-catheter endoscopic-assisted ventricular catheter placement.

RESULTS

During 25 months, 16 children (ages 3 months-18 years) underwent 18 procedures using the above technique. Indications for surgery were: proximal shunt malfunction with relatively small ventricles (ten children), proximal shunt malfunction with intraventricular membranes (one child), proximal shunt malfunction with distorted ventricles (one child), new shunt with small to medium sized ventricles (two children), or large ventricles and a loculated fourth ventricle secondary to an aqueductal web (two children). Fourteen procedures were technically successful. The catheter was properly located on postoperative imaging in 13 procedures. Frameless navigation was used in three cases.

CONCLUSIONS

Selective use of intra-catheter endoscopic-assisted proximal shunt placement is useful and may be indicated in small or distorted ventricles and in cases when fenestration of an intraventricular membrane or aqueductal web is indicated. The main value of such a technique is the ability to accurately place the catheter tip within distorted or small ventricles. Larger series are needed to refine these indications.