Smartphone-assisted guide for the placement of ventricular catheters

Image Quality and Related Outcomes of the ShuntScope-Guided Catheter Implantation in Adult Hydrocephalus: Experience of 63 Procedures

BACKGROUND

 Ventricular catheter (VC) placement in the selected subset of adult hydrocephalus can be highly challenging due to abnormal anatomical configuration or the need for trans-aqueductal stent placement. Transluminal endoscopy with the ShuntScope has been invented to increase the success rate of catheter placement. This study evaluates the image qualities of ShuntScope and related surgical outcomes in adults.

METHODS

 A retrospective analysis of all adult patients undergoing VC placement using the ShuntScope from November 2011 to July 2022 in the authors' department was performed. Demographic, clinical, and radiologic data were evaluated. The visualization quality of the intraoperative endoscopy was stratified into excellent, medium, and poor, and compared to the postoperative catheter tip placement. Follow-up evaluation included the surgical revision rate due to proximal catheter misplacement.

RESULTS

 A total of 63 ShuntScope-assisted surgeries have been performed on 60 adults. The mean age of the patients was 48.43 years. The most common underlying pathology was a tumor- or cyst-related cerebrospinal fluid (CSF) impairment in 38.33%, followed by a pseudotumor cerebri in 21.66%. The achieved image quality was excellent in 39.68%, medium in 47.62%, and poor in 12.7%. Ideal catheter placement was achieved in 79.37%. There were no intraoperative complications associated with the use of the ShuntScope. The revision rate due to suboptimal proximal VC placement was 4.76% during a mean follow-up period of 27.75 months. A statistical correlation between the image quality and accuracy of the catheter position was observed (p < 0.001).

CONCLUSION

 The ShuntScope can be considered an important addition to standard surgical tools in treating a selected subset of adult hydrocephalus. Direct visualization might even help achieve correct placement of the catheter in the cases with blurred vision and limited visual overview.

Ventricular Access Utilizing Cutaneous Reference Points: Statistical Analysis and Proposal of a New Ventricular Entry Point

OBJECTIVES

Perform radiologic measurements and analysis of normal brain computed tomography (CT) scans; delineate a new ventricular entry point from cutaneous landmarks, highlighting the potential surgical implications of these findings.

METHODS

Six radiologic distances (AR; BR; AL; BL, C, and D) were measured in normal brain CT scans using Horos software. Statistical analysis of the measurements was performed with minitab18 software based on age, sex, and side.

RESULTS

132 brain CT scans were analyzed, yielding the following mean results: AR distance: 2.1 cm; BR distance: 7 cm; AL distance: 2.1 cm; BL distance: 7.1 cm; C distance: 12.4 cm; D distance: 7 cm; new ventricular entry point: 12.4 cm posterior to the nasion, and 2.1 cm lateral to the midline.

CONCLUSIONS

The freehand technique for accessing the lateral ventricles is a common neurosurgical procedure but is often accompanied by complications. To address this, we suggest a novel entry point for ventricular access, determined by cutaneous reference points. This point is situated 12.4 cm posterior to the nasion along the midline and 2.1 cm lateral to the midline. Although our findings may play a role in presurgical planning for ventricular pathologies, future prospective studies are warranted.

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.

Navigated bedside implantation of external ventricular drains with mobile health guidance: technical note and case series

PURPOSE

External ventricular drain (EVD) implantation is one of the fundamental procedures of emergency neurosurgery usually performed freehand at bedside or in the operating room using anatomical landmarks. However, this technique is frequently associated with malpositioning leading to complications or dysfunction. Here, we describe a novel navigated bedside EVD insertion technique, which is evaluated in a clinical case series with the aim of safety, accuracy, and efficiency in neurosurgical emergency settings.

METHODS

From 2021 to 2022, a mobile health-assisted navigation instrument (Thomale Guide, Christoph Miethke, Potsdam, Germany) was used alongside a battery-powered single-use drill (Phasor Health, Houston, USA) for bedside EVD placement in representative neurosurgical pathologies in emergency situations requiring ventricular cerebrospinal fluid (CSF) relief and intracranial pressure (ICP) monitoring.

RESULTS

In all 12 patients (8 female and 4 male), navigated bedside EVDs were placed around the foramen of Monro at the first ventriculostomy attempt. The most frequent indication was aneurysmal subarachnoid hemorrhage. Mean operating time was 25.8 ± 15.0 min. None of the EVDs had to be revised due to malpositioning or dysfunction. Two EVDs were converted into a ventriculoperitoneal shunt. Drainage volume was 41.3 ± 37.1 ml per day in mean. Mean length of stay of an EVD was 6.25 ± 2.8 days. Complications included one postoperative subdural hematoma and cerebrospinal fluid infection, respectively.

CONCLUSION

Combining a mobile health-assisted navigation instrument with a battery-powered drill and an appropriate ventricular catheter may enable and enhance safety, accuracy, and efficiency in bedside EVD implantation in various pathologies of emergency neurosurgery without adding relevant efforts.

ShuntScope-Guided Versus Free-Hand Technique for Ventricular Catheter Placement: A Retrospective Comparative Study of Intraventricular Catheter Tip Position and Complication Rate

BACKGROUND

 The position of the ventricular catheter (VC) is essential for a proper function of cerebrospinal fluid diversion system. A ShuntScope-guided (SG) method might be helpful in reducing complications. The purpose of this study is to compare the accuracy of catheter placement and the complication and revision rates between SG and free-hand (FH) techniques.

METHODS

 This is a retrospective study based on a prospectively acquired database of patients who underwent VC placement between September 2018 and July 2021. Accuracy of catheter placement was graded on postoperative imaging using the 3-point Hayhurst grading system. Complication and revision rates were documented and compared between both groups with an average follow-up period of 20.84 months.

RESULTS

 Fifty-seven patients were included. The SG technique was used in 29 patients (mean age was 6.3 years, 1.4-27.7 years, 48.1% females), and the FH technique was used in 28 patients (mean age was 26.7 years, 0.83-79.5 years, 67.9% female). The success rate for the optimal placement of the VC with grade I on the Hayhurst scale was significantly higher in the SG group (93.1%) than in the FH group (60.7%), p = 0.012. The revision rate was higher in the FH group with 35.7% versus 20.7% in the SG group, p = 0.211.

CONCLUSION

 VC placement using the SG technique is a safe and effective procedure, which enabled a significantly higher success rate and lower revision and complication rate. Accordingly, we recommend using the SG technique especially in patients with difficult anatomy.

Image quality and related outcomes of the ShuntScope for catheter implantation in pediatric hydrocephalus-experience of 65 procedures

PURPOSE

Ventricular catheter implantation in pediatric hydrocephalus can become a highly challenging task due to abnormal anatomical configuration or the need for trans-aqueductal stent placement. Transluminal endoscopy with the ShuntScope has been invented to increase the rate of successful catheter placements. This study aims to evaluate ShuntScope's image qualities and related surgical outcomes in the pediatric population.

METHODS

A retrospective analysis of all pediatric patients undergoing ventricular catheter placement using the ShuntScope from 01/2012 to 01/2022 in the author's department was performed. Demographic, clinical, and radiological data were evaluated. The visualization quality of the intraoperative endoscopy was stratified into the categories of excellent, medium, and poor and compared to the postoperative catheter tip placement. Follow-up evaluation included the surgical revision rate due to proximal catheter occlusion.

RESULTS

A total of 65 ShuntScope-assisted surgeries have been performed on 51 children. The mean age was 5.1 years. The most common underlying pathology was a tumor- or cyst-related hydrocephalus in 51%. Achieved image quality was excellent in 41.5%, medium in 43%, and poor in 15.5%. Ideal catheter placement was achieved in 77%. There were no intraoperative complications and no technique-related morbidity associated with the ShuntScope. The revision rate due to proximal occlusion was 4.61% during a mean follow-up period of 39.7 years. No statistical correlation between image grade and accuracy of catheter position was observed (p-value was 0.290).

CONCLUSION

The ShuntScope can be considered a valuable addition to standard surgical tools in treating pediatric hydrocephalus. Even suboptimal visualization contributes to high rates of correct catheter placement and, thereby, to a favorable clinical outcome.

Maneuver protocol for outpatient telemetric intracranial pressure monitoring in hydrocephalus patients

INTRODUCTION

Telemetric intracranial pressure measurement (tICPM) offers new opportunities to acquire objective information in shunted and non-shunted patients. The sensor reservoir (SR) provides tICPM modality at a decent sampling rate as an integrated component of the CSF shunt system. The aim of this study is to perform tICPM during a defined protocol of maneuvers in an outpatient setting as feasibility study including either shunt-dependent patients or candidates for possible shunt therapy.

METHODS

A total of 17 patients received a SR and were investigated within a protocol of maneuver measurements involving different body postures (90°, 10°, 0°, and - 10°), breathing patterns (hypo- and hyperventilation), and mild venous congestion (Valsalva, Jugular vein compression), while the latter two were performed in lying postures (10° and 0°). The cohort included 11 shunted and 6 non-shunted (stand-alone-SR) patients. All measurements were evaluated using an ICP-analysis software (ICPicture, Miethke, Germany) looking at ICP changes and amplitude (AMP) characteristics.

RESULTS

The shunted patient group consisted of 11 patients (median age: 15.8 years; range: 4-35.2 years) with either a primary shunt (n=9) and 2 patients received a shunt after stand-alone-SR tICPM. Six patients were enrolled with a stand-alone SR (median age 11.9 years, range 3.6-17.7 years). In the stand-alone SR group, maneuver related ICP and AMP changes were more sensitive compared to shunted patients. Postural maneuvers caused significant ICP changes in all body positions in both groups. The highest ICP values were seen during Valsalva maneuver, provoked by the patients themselves. In the stand-alone group, significant higher ICP values during hyperventilation were observed compared to shunted individuals. In shunted patients, a significant correlation between ICP and AMP was observed only during hyperventilation maneuver, while this correlation was additionally seen in Valsalva and jugular vein compression in stand-alone patients.

CONCLUSION

SR-related tICPM is helpful to objectify diagnostic evaluation in patients with CSF dynamic disturbances. The defined protocol did result in a wide range of ICP changes with promising potential for effective outpatient tICPM investigation. Since the correlation of ICP and AMP was observed during mild venous congestion maneuvers it appears to be specifically helpful for the evaluation of intracranial compliance. Further investigations of maneuver-related tICPM in a larger population, including variable pathologies, are needed to further establish the protocol in the clinical practice.

Skin landmarks as ideal entry points for ventricular drainage, a radiological study

PURPOSE

Ventricular drainage remains a usual but challenging procedure for neurosurgical trainees. The objective of the study was to describe reliable skin landmarks for ideal entry points (IEPs) to catheterize brain ventricles via frontal and parieto-occipital approaches.

METHODS

We included 30 subjects who underwent brain MRI and simulated the ideal catheterization trajectories of lateral ventricles using anterior and posterior approaches and localized skin surface IEPs. The optimal frontal target was the interventricular foramen and that for the parieto-occipital approach was the atrium. We measured the distances between these IEPs and easily identifiable skin landmarks.

RESULTS

The frontal IEP was localized to 116.8 ± 9.3 mm behind the nasion on the sagittal plane and to 39.7 ± 4.9 mm lateral to the midline on the coronal plane. The ideal catheter length was estimated to be 68.4 ± 6.4 mm from the skin surface to the interventricular foramen. The parieto-occipital point was localized to 62.9 ± 7.4 mm above the ipsilateral tragus on the coronal plane and to 53.1 ± 9.1 mm behind the tragus on the axial plane. The ideal catheter length was estimated to be 48.3 ± 9.6 mm.

CONCLUSION

The IEP for the frontal approach was localized to 11 cm above the nasion and 4 cm lateral to the midline. The IEP for the parieto-occipital approach was 5.5 cm behind and 6 cm above the tragus. These measurements lightly differ from the classical descriptions of Kocher's point and Keen's point and seem relevant to neurosurgical practice while using an orthogonal insertion.

Bullseye EVD: preclinical evaluation of an intra-procedural system to confirm external ventricular drainage catheter positioning

PURPOSE

External ventricular drainage (EVD) is a life-saving procedure indicated for elevated intracranial pressure. A catheter is inserted into the ventricles to drain cerebrospinal fluid and release the pressure on the brain. However, the standard freehand EVD technique results in catheter malpositioning in up to 60.1% of procedures. This proof-of-concept study aimed to evaluate the registration accuracy of a novel image-based verification system "Bullseye EVD" in a preclinical cadaveric model of catheter placement.

METHODS

Experimentation was performed on both sides of 3 cadaveric heads (n = 6). After a pre-interventional CT scan, a guidewire simulating the EVD catheter was inserted as in a clinical EVD procedure. 3D structured light images (Einscan, Shining 3D, China) were acquired of an optical tracker placed over the guidewire on the surface of the scalp, along with three distinct cranial regions (scalp, face, and ear). A computer vision algorithm was employed to determine the guidewire position based on the pre-interventional CT scan and the intra-procedural optical imaging. A post-interventional CT scan was used to validate the performance of the Bullseye optical imaging system in terms of trajectory and offset errors.

RESULTS

Optical images which combined facial features and exposed scalp within the surgical field resulted in the lowest trajectory and offset errors of 1.28° ± 0.38° and 0.33 ± 0.19 mm, respectively. Mean duration of the optical imaging procedure was 128 ± 35 s.

CONCLUSIONS

The Bullseye EVD system presents an accurate patient-specific method to verify freehand EVD positioning. Use of facial features was critical to registration accuracy. Workflow automation and development of a user interface must be considered for future clinical evaluation.

The effect of image-guided ventricular catheter placement on shunt failure: a systematic review and meta-analysis

INTRODUCTION

Cerebrospinal fluid (CSF) diversion for the treatment of hydrocephalus is one of the most common neurosurgical procedures. Over the years, the development of the neuronavigation system has allowed the surgeon to be guided in real time during the procedures. Nevertheless, to date, the revision rate remains as high as 30-40%. The aim of this study was to investigate the role of intraoperative image guidance in the prevention of shunt failure. We herein report the first literature meta-analysis of image guidance and shunt revision rate in the pediatric population.

METHODS

Principal online databases were searched for English-language articles published between January, 1980, and December, 2021. Analysis was limited to articles that included patients younger than 18 years of age at the time of primary V-P shunt. Articles reporting combined results of free-hand and image-guided placement of ventricular catheter (VC) were included. The main outcome measure of the study was the revision rate in relation to the intraoperative tools. Secondary variables collected were the age of the patient and ventricle size. Statistical analyses and meta-analysis plots were done via R and RStudio. Heterogeneity was formally assessed using Q, I², and τ² statistics. To examine publication bias was performed a funnel plot analysis.

RESULT

A total of 9 studies involving 2017 pediatric patients were included in the meta-analysis. 55.9% of procedures were carried out with the aid of intraoperative tools, while 44.1% procedures were conducted free hand. The intraoperative tools used were ultrasound (9.1%), electromagnetic neuronavigation (21.07%), endoscope (67.32%), and combined images (2.4%).The image-guided placement of VC was not statistically associated with a lower revision rate. The pooled OR was 0.97 [CI 95% 0.88-1.07] with an I² statistics of 34%, t² of 0.018 and a p-value of 0.15 at heterogeneity analysis.

CONCLUSION

Our analysis suggest images guidance during VC shunt placement does not statistically affect shunt survival. Nevertheless, intraoperative tools can support the surgeon especially in patients with difficult anatomy, slit ventricles or complex loculated hydrocephalus.

Frameless neuronavigation with computer vision and real-time tracking for bedside external ventricular drain placement: a cadaveric study

OBJECTIVE

A major obstacle to improving bedside neurosurgical procedure safety and accuracy with image guidance technologies is the lack of a rapidly deployable, real-time registration and tracking system for a moving patient. This deficiency explains the persistence of freehand placement of external ventricular drains, which has an inherent risk of inaccurate positioning, multiple passes, tract hemorrhage, and injury to adjacent brain parenchyma. Here, the authors introduce and validate a novel image registration and real-time tracking system for frameless stereotactic neuronavigation and catheter placement in the nonimmobilized patient.

METHODS

Computer vision technology was used to develop an algorithm that performed near-continuous, automatic, and marker-less image registration. The program fuses a subject's preprocedure CT scans to live 3D camera images (Snap-Surface), and patient movement is incorporated by artificial intelligence-driven recalibration (Real-Track). The surface registration error (SRE) and target registration error (TRE) were calculated for 5 cadaveric heads that underwent serial movements (fast and slow velocity roll, pitch, and yaw motions) and several test conditions, such as surgical draping with limited anatomical exposure and differential subject lighting. Six catheters were placed in each cadaveric head (30 total placements) with a simulated sterile technique. Postprocedure CT scans allowed comparison of planned and actual catheter positions for user error calculation.

RESULTS

Registration was successful for all 5 cadaveric specimens, with an overall mean (± standard deviation) SRE of 0.429 ± 0.108 mm for the catheter placements. Accuracy of TRE was maintained under 1.2 mm throughout specimen movements of low and high velocities of roll, pitch, and yaw, with the slowest recalibration time of 0.23 seconds. There were no statistically significant differences in SRE when the specimens were draped or fully undraped (p = 0.336). Performing registration in a bright versus a dimly lit environment had no statistically significant effect on SRE (p = 0.742 and 0.859, respectively). For the catheter placements, mean TRE was 0.862 ± 0.322 mm and mean user error (difference between target and actual catheter tip) was 1.674 ± 1.195 mm.

CONCLUSIONS

This computer vision-based registration system provided real-time tracking of cadaveric heads with a recalibration time of less than one-quarter of a second with submillimetric accuracy and enabled catheter placements with millimetric accuracy. Using this approach to guide bedside ventriculostomy could reduce complications, improve safety, and be extrapolated to other frameless stereotactic applications in awake, nonimmobilized patients.

Severe Traumatic Brain Injury in children-paradigm of decompressive craniectomy compared to a historic cohort

PURPOSE

Traumatic brain injury (TBI) is one of the leading causes of death and disability in children. Medical therapy remains limited, and decompressive craniectomy (DC) is an established rescue therapy in case of elevated intracranial pressure (ICP). Much discussion deals with clinical outcome after severe TBI treated with DC, while data on the pediatric population is rare. We report our experience of treating severe TBI in two different treatment setups at the same academic institution.

METHODS

Forty-eight patients (≤ 16 years) were hospitalized with severe TBI (GCS ≤ 8 points) between 2008 and 2018 in a pediatric intensive care unit (ICU) at a specialized tertiary pediatric care center. Data on treatment, clinical status, and outcome was retrospectively analyzed. Outcome data included Glasgow Outcome Scale (GOS) at 3-, 12-, and 36-month follow-up. Data was compared to a historic cohort with 53 pediatric severe TBI patients treated at the same institution in a neurointensive care unit between 1996 and 2007. Ethical approval was granted (EA2/076/21).

RESULTS

Between 2008 and 2018, 11 patients were treated with DC. Compared to the historic cohort, patients were younger and GCS was worse, while in-hospital mortality and clinical outcome remained similar. A trend towards more aggressive EVD placement and the internal paradigm change for treatment in a specialized pediatric ICU was observed.

CONCLUSIONS

In children with severe TBI treated over two decades, clinical outcome was comparable and mostly favorable in two different treatment setups. Consequent therapy is warranted to maintain the positive potential for favorable outcome in children with severe TBI.

Image-Guided versus Freehand Ventricular Drain Insertion: Systematic Review and Meta-analysis

BACKGROUND

Ventricular drain insertion is a common neurosurgical procedure, typically performed using freehand approach. Use of image-guidance during drain insertion could improve the accuracy and reduce the incidence of drain failure. This review aim to assess the impact of image-guidance on drain placement accuracy, failure rate, and number of ventricular cannulation attempts.

METHODS

MEDLINE, EMBASE and Cochrane Library databases were searched from inception to February 2021 for studies comparing image-guided versus freehand ventricular drain insertion. Two reviewers independently screened studies for eligibility, extracted data, and assessed risk of bias and quality of evidence. Pooled data were reported using random effects model. ROBINS-I tool was used to assess risk of bias and GRADE approach was used to assess quality of evidence.

RESULTS

Of 1102 studies retrieved, 17 were included with a total of 3404 patients. . All included studies were of non-randomized design. Pooled data on drain accuracy and drain failure rates showed favourable effect of image-guidance with risk ratio of 1.31 (95% CI of 1.13 - 1.51, low quality evidence) and 0.63 (95% CI 0.48 - 0.83, moderate quality evidence), respectively. Pooled data were equivocal for number of attempts with mean difference score of -0.11 times (95% CI -0.31 - 0.09, very low-quality evidence). Heterogeneity was substantial for drain accuracy and failure rate outcomes.

CONCLUSIONS

In patients undergoing ventricular drain insertion, the use of image-guidance may enhance drain accuracy and reduce drain failure rate. The use of image-guidance probably does not decrease number of drain insertion attempts.

Stereotactic Ventriculostomy Guide

Introduction

Based on the anatomy of the frontal horn, a stereotactic ventriculostomy guidance system that does not need an elaborate setup and is suitable for ventricles of all sizes was developed. The objective of this paper is to describe this system and present the results of a cadaveric study in which this system was used.

Method

The system has a midline-based plate that is contoured to snugly fit the top of the head. It has two probe holders, one on each side at pre-set angles in coronal and sagittal planes, which enables the probe holders to point at the foramen of Monro. A cadaver study was done on eight donors. First, using the guidance system a 1.4 mm endoscope was inserted into the right frontal horn through a twist drill hole. Next, the scope was inserted into the right frontal horn on the same donors using the freehand method.

Result

With the guide, all eight ventricles were entered into on the first trial, and the foramen of Monro was visible end-on. With freehand technique: six ventricles were entered on the first try; however, the foramen of Monro was visible end-on only in one. In the other two, two to three attempts were needed. The guide facilitated 100% visibility for the end-on visibility of the foramen of Monro upon insertion and the results were statistically significant with t=7, df=7, p-value=0.000106.

Conclusion

This is a simple system, which is easy to use. The cadaveric study showed a high degree of accuracy to access the ventricles. The data shows significant improvement compared to the freehand technique.

Angulation towards coronal convexity measure and catheter length indication improves the quality of ventricular catheter placement - a smartphone-assisted guidance technique

BACKGROUND

Accurate placement of a ventricular catheter is crucial to reduce the risk of shunt failure. In the randomized, prospective, multicenter GAVCA trial, which evaluated the quality of ventricular catheter placement, the subgroup of patients with detailed length marked ventricular catheters (dVC) reflected a difference in the primary endpoint of optimal VC placement in contrast to the subgroup of patients with simplified length marked ventricular catheters (sVC). Objective of this analysis is to compare the dVC-group with the sVC-group as well as the smartphone-assisted guidance technique (GA) with the standard freehand technique (F) for catheter placement.

METHODS

We performed a further analysis of the GAVCA trial in two steps: 1^st part) detailed length marked VCs (providing detailed distance from tip to base (3-13cm) in 0.5cm markings) compared to simplified length marked VCs with length indication at 5 cm and 10 cm from tip to base and 2^nd part) comparing the smartphone-assisted guidance technique vs. freehand technique in the dVC-group.

RESULTS

1^st part) Data of 137 patients (104 dVC patients vs. 33 sVC patients) was eligible for this analysis. Optimal VC placement was achieved in 72.1% of the dVC-group and 39.4% of the sVC-group (p=<0.001, odds ratio (OR) 3.9, 95% CI 1.7-9.3). 2^nd part) The 104 dVC patients underwent a subgroup analysis concerning the catheter placement using different techniques for catheter placement (54 guidance technique (GA) vs. 50 freehand technique (F). Optimal catheter placement was achieved in 81.5% of the GA group and 62.0% of the F group (p=0.03, odds ratio 2.7, 95% CI 1.1-6.8). All patients who underwent guidance technique ventricular catheter placement (GA) were successful on primary puncture while for 8.7% of patients in the freehand group (F), multiple attempts were necessary (p=0.03).

CONCLUSIONS

This analysis suggests the combination of a smartphone-assisted guidance technique (GA) and use of a detailed length marked ventricular catheter (dVC) to improve the rate of accurate ventricular catheter placement. Compared with freehand technique (F), patients' safety is increased by a reduction of unsuccessful ventricular catheter placement attempts.

Hydrocephalus in Low and Middle-Income Countries - Progress and Challenges

Hydrocephalus remains one of the most commonly treated neurosurgical conditions worldwide. Caring for patients with hydrocephalus requires infrastructure and political support and initiative; these are often difficult to obtain in low- and middle-income countries (LMICs). Some innovations that have arisen in LMICs have traveled up the financial gradient to high-income countries, such as the combination of endoscopic third ventriculostomy with choroid plexus coagulation to manage hydrocephalus. The development of neuro-endoscopy has played a major role in managing hydrocephalus worldwide; however, LMICs still face specific challenges, such as limited access to shunt hardware, a disproportionately high incidence of post-infectious hydrocephalus, unique microbiological spectra, and often poor access to follow-up care and neuroimaging. This has received increased attention since the Lancet Commission on Global Surgery. The goal of improving access to quality neurosurgical care through various initiatives in LMICs will be discussed in this manuscript. The need for neurosurgeons continues to grow in LMICs, where better access to neurosurgical care, adequate neurosurgical training and political support, and patient education are needed to improve the quality of life for patients with common neurosurgical conditions. Despite these challenges, treating hydrocephalus remains a worthwhile endeavor for many patients.

Advances in CSF shunt devices and their assessment for the treatment of hydrocephalus

INTRODUCTION

Hydrocephalus is a neurological disorder caused by excessive accumulation of the cerebrospinal fluid (CSF) in the ventricles of the brain. It can be treated by diverting the extra fluid to different parts of the body using a device called a shunt. This paper reviews different shunt devices that are used for this purpose.

AREAS COVERED

Shunts have high failure rates either due to infection or mechanical failure, therefore there is still ongoing work to address these two main handicaps. They require additional devices for performance assessment. Here, the paper also reviews different approaches for assessing shunt limitations. Moreover, future prospects are also discussed.

EXPERT OPINION

This study shows that shunt devices still remain an important treatment option for hydrocephalus. However, further efforts are required to design more advanced shunts, to eliminate high failure rates in clinical use. Sophisticated sensor systems that can accurately detect and regulate changes in CSF drainage to optimize drainage for individual needs. Moreover, shunt infection problem is still present despite recent improvements such as antibiotic impregnated catheters.

White Matter Governed Superior Frontal Sulcus Surgical Paradigm: A Radioanatomic Microsurgical Study-Part II

BACKGROUND

Kocher's point (KP) and its variations have provided standard access to the frontal horn (FH) for over a century. Anatomic understanding of white matter tracts (WMTs) has evolved, now positioning us to better inform the optimal FH trajectory.

OBJECTIVE

To (1) undertake a literature review analyzing entry points (EPs) to the FH; (2) introduce a purpose-built WMT-founded superior frontal sulcus parafascicular (SFSP)-EP also referred to as the Kassam-Monroy entry point (KM-EP); and (3) compare KM-EP with KP and variants with respect to WMTs.

METHODS

(1) Literature review (PubMed database, 1892-2018): (a) stratification based on the corridor: i. ventricular catheter; ii. through-channel endoscopic; or iii. portal; (b) substratification based on intent: i. preoperatively planned or ii. intraoperative (postdural opening) for urgent ventricular drainage. (2) Anatomic comparisons of KM-EP, KP, and variants via (a) cadaveric dissections and (b) magnetic resonance-diffusion tensor imaging computational 3D modeling.

RESULTS

A total of 31 studies met inclusion criteria: (a) 9 utilized KP coordinate (1 cm anterior to the coronal suture (y-axis) and 3 cm lateral of the midline (x-axis) approximated by the midpupillary line) and 22 EPs represented variations. All 31 traversed critical subcortical WMTs, specifically the frontal aslant tract, superior longitudinal fasciculus II, and inferior fronto-occipital fasciculus, whereas KM-EP (x = 2.3, y = 3.5) spares these WMTs.

CONCLUSION

KP (x = 3, y = 1) conceived over a century ago, prior to awareness of WMTs, as well as its variants, anatomically place critical WMTs at risk. The KM-EP (x = 2.3, y = 3.5) is purpose built and founded on WMTs, representing anatomically safe access to the FH. Correlative clinical safety, which will be directly proportional to the size of the corridor, is yet to be established in prospective studies.

Stereotactic guide for posterior approach to lateral ventricle

Background

Free-hand tapping of the lateral ventricle through the posterior approach is a standard procedure. There are occasions, however, when more than one pass is needed. One way to make it easy and safe is to use a neuro-navigation approach. This requires extra setup. Therefore, the authors in this paper describe the use of a simple device to accurately place the catheter tip in the frontal horn.

Main body

The device is rectangular with two open arms with co-linear free ends. Based on axial CT or MR images, a trajectory that travels within the ventricle from the posterior to the anterior horn is chosen. The anterior and posterior points of the trajectory are marked on the scalp. A burr hole is placed at the posterior point. The anterior free end is then attached to the anterior trajectory point on the scalp using an EKG pad and to the posterior to a plug placed in the burr hole. The ventricle is tapped through a central hole in the burr hole plug. All 12 patients had accurate catheter placement at the first attempt using this system.

Short conclusion

This is a simple device that used CT or MR images and surface markings to accurately tap the ventricle.

Skin landmarks to main cerebral structures: how to identify the main cerebral sulci? An anatomical study

PURPOSE

Neuronavigation is used in neurosurgical practice to locate the cortical structures. If this tool is unavailable, basic anatomical knowledge should be used. Craniometry has been rarely detailed in recent literature, systematically using bony landmarks. The aim of this study is to describe skin landmarks for neurosurgical practice.

METHODS

Dissection of 10 hemispheres with insertion of radio-opaque markers within the limits of lateral sulcus, central and pre-central sulci, and preoccipital notch. Computed tomography was performed in all cases and multiplanar reconstructions were performed. Maximal intensity projection (MIP) fusion images were used for measurements between known skin landmarks and sulci of interests.

RESULTS

The Anterior Sylvian Point is measured 31.8 ± 2.8 mm behind the orbital wall, 36.9 ± 3 mm above the zygomatic arch. The horizontal part of the lateral sulcus is measured 59 ± 6 mm above the tragus. The Superior Rolandic Point is measured 190.7 ± 4.5 mm behind the nasion. The Pre-occipital Notch is measured 37.0 ± 6.9 mm above the tragus and 67.1 ± 6.4 mm behind. The Ideal Entry Points (IEP) for ventricular punctures are measured 120.2 ± 7 mm behind the nasion and 33.8 ± 3 mm laterally for the frontal IEP, and 61.3 mm ± 2.5 mm above and 64.7 ± 6.8 mm behind the tragus for the parieto-occipital IEP.

CONCLUSION

In this study, we described simple skin landmarks for lateral sulcus, central sulcus, preoccipital notch, and an IEP for ventricular drainage. Precise knowledge of brain sulcal anatomy will guide patient's positioning, skin incision, and craniotomies; and permits checking of imaging data provided by neuronavigation systems.

Freehand stereotactic ventricular catheter insertion for ventriculoperitoneal shunts based on individualized radio-anatomical landmarks

INTRODUCTION

The accurate placement of the ventricular catheter (VC) is critical in reducing the incidence of proximal failure of ventriculoperitoneal shunts (VPSs). The standard freehand technique is based on validated external anatomical landmarks but remains associated with a relatively high rate of VC malposition. Already proposed alternative methods have all their specific limitations. Herein, we evaluate the accuracy of our adapted freehand technique based on an individualized radio-anatomical approach. Reproducing the preoperative imaging on the patient's head using common anatomical landmarks allows to define stereotactic VC coordinates to be followed at surgery.

MATERIAL AND METHODS

Fifty-five consecutive patients treated with 56 VPS between 11/2005 and 02/2020 fulfilled the inclusion criteria of this retrospective study. Burr hole coordinates, VC trajectory, and length were determined in all cases on preoperative computed tomography (CT) scan and were accurately reported on patients' head. The primary endpoint was to evaluate VC placement accuracy. The secondary endpoint was to evaluate the rate and nature of postoperative VC-related complications.

RESULTS

Our new technique was applicable in all patients and no VC-related complications were observed. Postoperative imaging showed VC optimally placed in 85.7% and sub-optimally placed in 14.3% of cases. In all procedures, all the holes on the VC tip were found in the ventricular system.

CONCLUSIONS

This simple individualized technique improves the freehand VC placement in VPS surgery, making its accuracy comparable to that of more sophisticated and expensive techniques. Further randomized controlled studies are required to compare our results with those of the other available techniques.

A virtual reality-based data analysis for optimizing freehand external ventricular drain insertion

PURPOSE

This work exploits virtual reality technique to analyse and optimize the preoperative planning of freehand external ventricular drain (EVD) insertion. Based on the three-dimensional (3D) virtual brain models, neurosurgeons can directly observe the anatomical landmarks and complete the simulated EVD insertion. Simulation data is used to optimize preoperative planning parameters to ensure the surgical performance.

METHODS

We used the computed tomography (CT) scans to construct the 3D virtual brain models. A group of EVD insertions were simulated by inserting virtual catheters at different entry points. The key parameters including the location of entry point, the catheter orientation, the catheter tip position on lateral ventricles, and the insertion depth were recorded. A data analysis method was then applied to optimize these parameters, resulting in the optimal parameters for the EVD insertion.

RESULTS

When the lateral distance of entry point ranged from 2.5 to 3 cm, the success rate of 204 cases was 97.79%, which was higher than that of the classic method (59.52%). The optimal insertion angle towards the sagittal plane ranged from 10.46° to 12.73°. To prevent penetrating the lateral ventricles, the insertion depth was optimized to be 3.28 to 4.58 cm.

CONCLUSIONS

The proposed data analysis method is helpful to optimize the key parameters of the preoperative planning, and provides useful references for neurosurgeons to perform the freehand EVD insertion. The EVD insertion experiments on 3D printing model had a success rate of 93.75%, which verified the effectiveness of the data analysis.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Treatment of Pediatric Hydrocephalus: Update of the 2014 Guidelines

BACKGROUND

The Congress of Neurological Surgeons reviews its guidelines according to the Institute of Medicine's recommended best practice of reviewing guidelines every 5 yrs. The authors performed a planned 5-yr review of the medical literature used to develop the “Pediatric hydrocephalus: systematic literature review and evidence-based guidelines” and determined the need for an update to the original guideline based on new available evidence.

OBJECTIVE

To perform an update to include the current medical literature for the “Pediatric hydrocephalus: systematic literature review and evidence-based guidelines”, originally published in 2014.

METHODS

The Guidelines Task Force used the search terms and strategies consistent with the original guidelines to search PubMed and Cochrane Central for relevant literature published between March 2012 and November 2019. The same inclusion/exclusion criteria were also used to screen abstracts and to perform the full-text review. Full text articles were then reviewed and when appropriate, included as evidence and recommendations were added or changed accordingly.

RESULTS

A total of 41 studies yielded by the updated search met inclusion criteria and were included in this update.

CONCLUSION

New literature resulting from the update yielded a new recommendation in Part 2, which states that neuro-endoscopic lavage is a feasible and safe option for the removal of intraventricular clots and may lower the rate of shunt placement (Level III). Additionally a recommendation in part 7 of the guideline now states that antibiotic-impregnated shunt tubing reduces the risk of shunt infection compared with conventional silicone hardware and should be used for children who require placement of a shunt (Level I). &lt;https://www.cns.org/guidelines/browse-guidelines-detail/pediatric-hydrocephalus-guideline&gt;

Ultrasound-Guided Insertion of the Ventricular Catheter in Ventriculoperitoneal Shunt Surgery: Evaluation of Accuracy and Feasibility in a Prospective Cohort

OBJECTIVE

 Ventriculoperitoneal shunt (VPS) placement is one of the most frequent neurosurgical procedures. The position of the proximal catheter is important for shunt survival. Shunt placement is done either without image guidance ("freehand") according to anatomical landmarks or by use of various image-guided techniques. Studies evaluating ultrasound-guided (US-G) VPS placement are sparse. We evaluate the accuracy and feasibility of US-G VPS placement, and compare it to freehand VPS placement.

METHODS

 We prospectively collected data of consecutive patients undergoing US-G VPS placement. Thereafter, the US cohort was compared with a cohort of patients in whom VPS was inserted using the freehand technique (freehand cohort). Primary outcome was accuracy of catheter positioning, and secondary outcomes were postoperative improvement in Evans' index (EI), rates of shunt dysfunction and revision surgery, perioperative complications, as well as operation, and anesthesia times.

RESULTS

 We included 15 patients undergoing US-G VPS insertion. Rates of optimally placed shunts were higher in the US cohort (67 vs. 49%, p = 0.28), whereas there were no malpositioned VPS (0%) in the US cohort, compared with 10 (5.8%) in the freehand cohort (p = 0.422). None of the factors in the univariate analysis showed significant association with nonoptimal (NOC) VPS placement in the US cohort. The mean EI improvement was significantly better in the US cohort than in the freehand cohort (0.043 vs. 0.014, p = 0.035).

CONCLUSION

 Based on our preliminary results, US-G VPS placement seems to be feasible, safe, and increases the rate of optimally placed catheters.

Surgical Performance Determines Functional Outcome Benefit in the Minimally Invasive Surgery Plus Recombinant Tissue Plasminogen Activator for Intracerebral Hemorrhage Evacuation (MISTIE) Procedure

BACKGROUND

Minimally invasive surgery procedures, including stereotactic catheter aspiration and clearance of intracerebral hemorrhage (ICH) with recombinant tissue plasminogen activator hold a promise to improve outcome of supratentorial brain hemorrhage, a morbid and disabling type of stroke. A recently completed Phase III randomized trial showed improved mortality but was neutral on the primary outcome (modified Rankin scale score 0 to 3 at 1 yr).

OBJECTIVE

To assess surgical performance and its impact on the extent of ICH evacuation and functional outcomes.

METHODS

Univariate and multivariate models were used to assess the extent of hematoma evacuation efficacy in relation to mRS 0 to 3 outcome and postulated factors related to patient, disease, and protocol adherence in the surgical arm (n = 242) of the MISTIE trial.

RESULTS

Greater ICH reduction has a higher likelihood of achieving mRS of 0 to 3 with a minimum evacuation threshold of ≤15 mL end of treatment ICH volume or ≥70% volume reduction when controlling for disease severity factors. Mortality benefit was achieved at ≤30 mL end of treatment ICH volume, or >53% volume reduction. Initial hematoma volume, history of hypertension, irregular-shaped hematoma, number of alteplase doses given, surgical protocol deviations, and catheter manipulation problems were significant factors in failing to achieve ≤15 mL goal evacuation. Greater surgeon/site experiences were associated with avoiding poor hematoma evacuation.

CONCLUSION

This is the first surgical trial reporting thresholds for reduction of ICH volume correlating with improved mortality and functional outcomes. To realize the benefit of surgery, protocol objectives, surgeon education, technical enhancements, and case selection should be focused on this goal.

sEVD-smartphone-navigated placement of external ventricular drains

BACKGROUND

Currently, the trajectory for insertion of an external ventricular drain (EVD) is mainly determined using anatomical landmarks. However, non-assisted implantations frequently require multiple attempts and are associated with EVD malpositioning and complications. The authors evaluated the feasibility and accuracy of a novel smartphone-guided, angle-adjusted technique for assisted implantations of an EVD (sEVD) in both a human artificial head model and a cadaveric head.

METHODS

After computed tomography (CT), optimal insertion angles and lengths of intracranial trajectories of the EVDs were determined. A smartphone was calibrated to the mid-cranial sagittal line. Twenty EVDs were placed using both the premeasured data and smartphone-adjusted insertion angles, targeting the center of the ipsilateral ventricular frontal horn. The EVD positions were verified with post-interventional CT.

RESULTS

All 20 sEVDs (head model, 8/20; cadaveric head, 12/20) showed accurate placement in the ipsilateral ventricle. The sEVD tip locations showed a mean target deviation of 1.73° corresponding to 12 mm in the plastic head model, and 3.45° corresponding to 33 mm in the cadaveric head. The mean duration of preoperative measurements on CT data was 3 min, whereas sterile packing, smartphone calibration, drilling, and implantation required 9 min on average.

CONCLUSIONS

By implementation of an innovative navigation technique, a conventional smartphone was used as a protractor for the insertion of EVDs. Our ex vivo data suggest that smartphone-guided EVD placement offers a precise, rapidly applicable, and patient-individualized freehand technique based on a standard procedure with a simple, cheap, and widely available multifunctional device.

Medical photography with a mobile phone: useful techniques, and what neurosurgeons need to know about HIPAA compliance

Medical photographs are commonly employed to enhance education, research, and patient care throughout the neurosurgical discipline. Current mobile phone camera technology enables surgeons to quickly capture, document, and share a patient scenario with colleagues. Research demonstrates that patients generally view clinical photography favorably, and the practice has become an integral part of healthcare. Neurosurgeons in satellite locations often rely on residents to send photographs of diagnostic imaging studies, neurological examination findings, and postoperative wounds. Images are also frequently obtained for research purposes, teaching and learning operative techniques, lectures and presentations, comparing preoperative and postoperative outcomes, and patient education. However, image quality and technique are highly variable. Capturing and sharing photographs must be accompanied by an awareness of the legal ramifications of the Health Insurance Portability and Accountability Act (HIPAA). HIPAA compliance is straightforward when one is empowered with the knowledge of what constitutes a patient identifier in a photograph. Little has been published to describe means of improving the accuracy and educational value of medical photographs in neurosurgery. Therefore, in this paper, the authors present a brief discussion regarding four easily implemented photography skills every surgeon who uses his or her mobile phone for patient care should know: 1) provide context, 2) use appropriate lighting, 3) use appropriate dimensionality, and 4) manage distracting elements. Details of the HIPAA-related components of mobile phone photographs and patient-protected health information are also included.

GAVCA Study: Randomized, Multicenter Trial to Evaluate the Quality of Ventricular Catheter Placement with a Mobile Health Assisted Guidance Technique

BACKGROUND

Freehand ventricular catheter placement may represent limited accuracy for the surgeon's intent to achieve primary optimal catheter position.

OBJECTIVE

To investigate the accuracy of a ventricular catheter guide assisted by a simple mobile health application (mhealth app) in a multicenter, randomized, controlled, simple blinded study (GAVCA study).

METHODS

In total, 139 eligible patients were enrolled in 9 centers. Catheter placement was evaluated by 3 different components: number of ventricular cannulation attempts, a grading scale, and the anatomical position of the catheter tip. The primary endpoint was the rate of primary cannulation of grade I catheter position in the ipsilateral ventricle. The secondary endpoints were rate of intraventricular position of the catheter's perforations, early ventricular catheter failure, and complications.

RESULTS

The primary endpoint was reached in 70% of the guided group vs 56.5% (freehand group; odds ratio 1.79, 95% confidence interval 0.89-3.61). The primary successful puncture rate was 100% vs 91.3% (P = .012). Catheter perforations were located completely inside the ventricle in 81.4% (guided group) and 65.2% (freehand group; odds ratio 2.34, 95% confidence interval 1.07-5.1). No differences occurred in early ventricular catheter failure, complication rate, duration of surgery, or hospital stay.

CONCLUSION

The guided ventricular catheter application proved to be a safe and simple method. The primary endpoint revealed a nonsignificant improvement of optimal catheter placement among the groups. Long-term follow-up is necessary in order to evaluate differences in catheter survival among shunted patients.

Development of a brain simulator for intracranial targeting: Technical note

Learning and enhancing of manual skills in the field of neurosurgery requires an intensive training which can be maintained by using virtual reality (VR)-based or physical model (PM)-based simulators. However, both simulator types are limited to one specific intracranial procedure, e.g. the application of an external ventricular drainage (EVD), and they do not provide any accuracy verification. We present a brain simulator which consists of a 3D human skull model having five electroconductive balls in its interior. The installed balls represent intracranial target points providing various accuracy problems in neuronavigation. They are electrically contacted to lamps getting an optical signal by touching them with a current-carrying target tool. The simulator fulfills two requirements: First, it can prove the accuracy of navigation systems and algorithms. Second, it allows becoming familiar with a navigation system's application in an ex vivo setting. It could be a helpful device in neurosurgical skills labs.

Surgical Performance in Minimally Invasive Surgery Plus Recombinant Tissue Plasminogen Activator for Intracerebral Hemorrhage Evacuation Phase III Clinical Trial

BACKGROUND

Minimally invasive thrombolytic evacuation of intracerebral hematoma is being investigated in the ongoing phase III clinical trial of Minimally Invasive Surgery plus recombinant Tissue plasminogen activator for Intracerebral hemorrhage Evacuation (MISTIE III).

OBJECTIVE

To assess the accuracy of catheter placement and efficacy of hematoma evacuation in relation to surgical approach and surgeon experience.

METHODS

We performed a trial midpoint interim assessment of 123 cases that underwent the surgical procedure. Accuracy of catheter placement was prospectively assessed by the trial Surgical Center based on prearticulated criteria. Hematoma evacuation efficacy was evaluated based on absolute volume reduction, percentage hematoma evacuation, and reaching the target end-of-treatment volume of <15 mL. One of 3 surgical trajectories was used: anterior (A), posterior (B), and lobar (C). Surgeons were classified based on experience with the MISTIE procedure as prequalified, qualified with probation, and fully qualified.

RESULTS

The average hematoma volume was 49.7 mL (range 20.0-124), and the mean evacuation rate was 71% (range 18.4%-99.8%). First placed catheters were 58% in good position, 28% suboptimal (but suitable to dose), and 14% poor (requiring repositioning). Posterior trajectory (B) was associated with significantly higher rates of poor placement (35%, P = .01). There was no significant difference in catheter placement accuracy among surgeons of varying experience. Hematoma evacuation efficacy was not significantly different among the 3 surgical approaches or different surgeons' experience.

CONCLUSION

Ongoing surgical education and quality monitoring in MISTIE III have resulted in consistent rates of hematoma evacuation despite technical challenges with the surgical approaches and among surgeons of varying experience.

The use of a smartphone-assisted ventricle catheter guide for Ommaya reservoir placement-experience of a retrospective bi-center study

BACKGROUND

For intraventricular chemotherapy (IVC) as part of many oncological treatment protocols, Ommaya reservoir is enabling repeated access to the cerebro-spinal fluid (CSF). The correct placement of the catheter in the ventricle is essential for correct application of drugs, which is enabled by sophisticated techniques such as neuronavigation.

OBJECTIVE

In a bi-center retrospective study, we reviewed our experience using a smartphone-assisted ventricle catheter guide as simple solution for correct Ommaya reservoir placement.

METHODS

Sixty Ommaya reservoirs have been placed in 60 patients between 2011 and 2017 with the smartphone-assisted ventricular catheter guidance technique. Patient characteristics, preoperative frontal and occipital horn ratio (FOHR), postoperative catheter position, and complications were assessed.

RESULTS

The majority of our patients (71.6%) have got narrow or slit-like ventricles (FOHR ≤ 0.4). All Ommaya reservoirs were placed successfully. Fifty-eight ventricular catheters (97%) were inserted at the first and 2 (3%) at the second attempt using the same technique. No immediate perioperative complications were observed. All catheters (100%) could be used for IVC. Postoperative imaging was available in 52 patients. Thirty-two (61.5%) of ventricular catheters were rated as grade I, 20 (38.5%) as grade II, and none (0%) as grade III. Four patients (6.7%) showed postoperative complications during a median follow-up of 8.5 months (hydrocephalus, n = 1; infection, n = 1; parenchymal cyst around catheter, n = 1; shunt revision, n = 1).

CONCLUSIONS

The smartphone-assisted guide offers decent accuracy of ventricle catheter placement with ease and simplicity for a small surgical intervention. We propose this technique as routine tool for Ommaya reservoir placement independent of lateral ventricular size to decrease the rate of ventricle catheter malposition as reasonable alternative to a neuronavigation system.

[Placement of a ventricular catheter into narrow lateral ventricles. Popular navigation]

Placement of a ventricular catheter is the most common and easiest procedure in neurosurgery. Usually, the procedure is performed using anatomical landmarks. However, despite the apparent ease of this manipulation, its results are not always satisfactory. According to the literature data, the rate of improperly placed ventricular catheters amounts to 10-40%, which is directly correlated with the risk of shunt dysfunction. The use of special equipment, such as ultrasound scanners, endoscopes, stereotactic devices, and neuronavigation systems, significantly increases success of surgery. However, the high cost and complexity of equipment confine its use at neurosurgical centers, and increased surgery time limits routine use of the equipment. A Thomale guide provides the accuracy comparable to that of modern navigation systems and, at the same time, is a cheap and easy-to-use device.

AIM

To determine capabilities and master a technique of using the Thomale guide during placement of ventricular catheters.

MATERIAL AND METHODS

Twenty seven surgeries wich Thomale guide were performed at the Rogachev Federal Research Center of Pediatric Hematology, Oncology, and Immunology in the period from April 2015 to November 2016. The Ommaya reservoir was placed in 23 cases; there were 2 ventriculoperitoneal shunting procedures; external ventricular drainage was placed in 2 cases. In 19 cases, the catheter was placed into narrow lateral ventricles.

RESULTS

In all 27 cases, the ventricular catheter was successfully placed, at the first attempt, into the anterior horn of the lateral ventricle.

CONCLUSION

The Thomale guide is a simple but reliable device for accurate and quick placement of a ventricular catheter into the lateral ventricles, regardless of their size.

A non-hydrocephalic goat experimental model to evaluate a ventriculosinus shunt

The ventriculosinus shunt is a promising treatment for hydrocephalus. Currently, different shunt techniques exist, and it is not clear whether one is preferable. This pilot study reports on a non-hydrocephalic goat model (Saanen breed) that provides opportunities to evaluate and optimize several aspects of the ventriculosinus shunt technique. Analysis of the coagulation properties of 14 goats by a viscoelastic coagulation monitor showed that goats have a hypercoagulable state compared to humans. This property can be partially counteracted by antiplatelet drugs. During implantation of a ventriculosinus shunt, a pulsatile reflux of blood was observed. After implantation, the animals recovered to their preoperative state, and none of them developed a superior sagittal sinus thrombosis. Evaluation of the shunts after 16 days showed an obstructing luminal clot. Several model-related factors may have promoted this obstruction: the absence of hydrocephalus, the hypercoagulability of caprine blood and the smaller dimensions of the caprine superior sagittal sinus. However, the pulsatile reflux of blood, which is caused by the compliance of the shunt system distal to the valve, may have been an important factor as well. In conclusion, the non-hydrocephalic goat model limits animal suffering and simplifies the study protocol. This model allows researchers to evaluate their implantation technique and shunt hardware but not the efficacy of the treatment or shunt survival.

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.

Ventriculostomy-associated hemorrhage: a risk assessment by radiographic simulation

OBJECTIVE

Ventriculostomy entry sites are commonly selected by freehand estimation of Kocher's point or approximations from skull landmarks and a trajectory toward the ipsilateral frontal horn of the lateral ventricles. A recognized ventriculostomy complication is intracranial hemorrhage from cortical vessel damage; reported rates range from 1% to 41%. In this report, the authors assess hemorrhagic risk by simulating traditional ventriculostomy trajectories and using CT angiography (CTA) with venography (CTV) data to identify potential complications, specifically from cortical draining veins.

METHODS

Radiographic analysis was completed on 50 consecutive dynamic CTA/CTV studies obtained at a tertiary-care academic neurosurgery department. Image sections were 0.5 mm thick, and analysis was performed on a venous phase that demonstrated high-quality opacification of the cortical veins and sagittal sinus. Virtual ventriculostomy trajectories were determined for right and left sides using medical diagnostic imaging software. Entry points were measured along the skull surface, 10 cm posteriorly from the nasion, and 3 cm laterally for both left and right sides. Cannulation was simulated perpendicular to the skull surface. Distances between the software-traced cortical vessels and the virtual catheter were measured. To approximate vessel injury by twist drill and ventricular catheter placement, veins within a 3-mm radius were considered a hemorrhage risk.

RESULTS

In 100 virtual lines through Kocher's point toward the ipsilateral ventricle, 19% were predicted to cause cortical vein injury and suspected hemorrhage (radius ≤ 3 mm). Little difference existed between cerebral hemispheres (right 18%, left 20%). The average (± SD) distance from the trajectory line and a cortical vein was 7.23 ± 4.52 mm. In all 19 images that predicted vessel injury, a site of entry for an avascular zone near Kocher's point could be achieved by moving the trajectory less than 1.0 cm laterally and less than 1.0 cm along the anterior/posterior axis, suggesting that empirical measures are suboptimal, and that patient-specific coordinates based on preprocedural CTA/CVA imaging may optimize ventriculostomy in the future.

CONCLUSIONS

In this institutional radiographic imaging analysis, traditional methods of ventriculostomy site selection predicted significant rates of cortical vein injury, matching described rates in the literature. CTA/CTV imaging potentiates identification of patient-specific cannulation sites and custom trajectories that avoid cortical vessels, which may lessen the risk of intracranial hemorrhage during ventriculostomy placement. Further development of this software is underway to facilitate stereotactic ventriculostomy and improve outcomes.

Adjustable Ghajar Guide Technique for Accurate Placement of Ventricular Catheters: A Pilot Study

Objective

An adjustable Ghajar guide is presented to improve the accuracy of the original Ghajar guide technique. The accuracy of the adjustable Ghajar guide technique is also investigated.

Methods

The coronal adjustment angle from the orthogonal catheter trajectory at Kocher’s point is determined based on coronal head images using an electronic picture archiving and communication system. For the adjustable Ghajar guide, a protractor is mounted on a C-shaped basal plate that is placed in contact with the margin of a burrhole, keeping the central 0° line of the protractor orthogonal to the calvarial surface. A catheter guide, which is moved along the protractor and fixed at the pre-determined adjustment angle, is then used to guide the ventricular catheter into the frontal horn adjacent to the foramen of Monro. The adjustable Ghajar guide technique was applied to 20 patients, while a freehand technique based on the surface anatomy of the head was applied to another 47 patients. The accuracy of the ventricular catheter placement was then evaluated using postoperative computed tomography scans.

Results

For the adjustable Ghajar guide technique (AGT) patients, the bicaudate index ranged from 0.23 to 0.33 (mean±standard deviation [SD]: 0.27±0.03) and the adjustment angle ranged from 0° to 10° (mean±SD: 5.2°±3.2°). All the AGT patients experienced successful cerebrospinal fluid diversion with only one pass of the catheter. Optimal placement of the ventricular catheter in the ipsilateral frontal horn approximating the foramen of Monro (grade 1) was achieved in 19 patients (95.0%), while a suboptimal trajectory into a lateral corner of the frontal horn passing along a lateral wall of the frontal horn (grade 3) occurred in 1 patient (5.0%). Thus, the AGT patients experienced a significantly higher incidence of optimal catheter placement than the freehand catheterized patients (95.0% vs. 68.3%, p=0.024). Moreover, none of the AGT patients experienced any tract hemorrhages along the catheter or procedure-related complications.

Conclusion

The proposed adjustable Ghajar guide technique, using angular adjustment in the coronal plane from the orthogonal trajectory at Kocher’s point, facilitates accurate freehand placement of a ventricular catheter for hydrocephalic patients.

Placement accuracy of external ventricular drain when comparing freehand insertion to neuronavigation guidance in severe traumatic brain injury

BACKGROUND

External ventricular drain (EVD) placement is a frequently performed neurosurgical procedure. Inaccuracies in drain positioning and the need for multiple passes using the classic freehand insertion technique is well reported in the literature, especially in the traumatic brain injury (TBI) population. The purpose of this study was to evaluate if electromagnetic neuronavigation guidance for EVD insertion improves placement accuracy and minimizes the number of passes in severe TBI patients.

METHODS

Navigation was applied prospectively for all new severe TBI patients who required ventricular catheter placement over a period of 1 year, and compared with a retrospective cohort of severe TBI patients who had EVD inserted freehand in the preceding year. The placement accuracy was evaluated using the Kakarla grading system; the number of passes was also compared.

RESULTS

Fifty-four cases were recruited: 35 (64.8%) had their EVD placed using the freehand technique and 19 (35.2%) using navigation guidance. In the navigation group, the placement accuracy was: 94.7% (18/19) grade 1, 5.3% (1/19) grade 2, and none at grade 3. In comparison, freehand placement was associated with misplacement (grades 2 and 3) in 42.9% of the cases (p value = 0.009). The number of passes was significantly lower in the navigation group (mean of 1.16 ± 0.38), compared with the freehand group (mean of 1.63 ± 0.88) (p value = 0.018).

CONCLUSIONS

Using the navigation to guide EVD placement was associated with a significantly better accuracy and a lower number of passes in severe TBI patients.

Revisiting the rules for freehand ventriculostomy: a virtual reality analysis

OBJECTIVE Frontal ventriculostomy is one of the most frequent and standardized procedures in neurosurgery. However, many first and subsequent punctures miss the target, and suboptimal placement or misplacement of the catheter is common. The authors therefore reexamined the landmarks and rules to determine the entry point and trajectory with the best hit rate (HtR). METHODS The authors randomly selected CT scans from their institution's DICOM pool that had been obtained in 50 patients with normal ventricular and skull anatomy and without ventricular puncture. Using a 5 × 5-cm frontal grid with 25 entry points referenced to the bregma, the authors examined trajectories 1) perpendicular to the skull, 2) toward classic facial landmarks in the coronal and sagittal planes, and 3) toward an idealized target in the middle of the ipsilateral anterior horn (ILAH). Three-dimensional virtual reality ventriculostomies were simulated for these entry points; trajectories and the HtRs were recorded, resulting in an investigation of 8000 different virtual procedures. RESULTS The best HtR for the ILAH was 86% for an ideal trajectory, 84% for a landmark trajectory, and 83% for a 90° trajectory, but only at specific entry points. The highest HtRs were found for entry points 3 or 4 cm lateral to the midline, but only in combination with a trajectory toward the contralateral canthus; and 1 or 2 cm lateral to the midline, but only paired with a trajectory toward the nasion. The same "pairing" exists for entry points and trajectories in the sagittal plane. For perpendicular (90°) trajectories, the best entry points were at 3-5 cm lateral to the midline and 3 cm anterior to the bregma, or 4 cm lateral to the midline and 2 cm anterior to the bregma. CONCLUSIONS Only a few entry points offer a chance of a greater than 80% rate of hitting the ILAH, and then only in combination with a specific trajectory. This "pairing" between entry point and trajectory was found both for landmark targeting and for perpendicular trajectories, with very limited variability. Surprisingly, the ipsilateral medial canthus, a commonly reported landmark, had low HtRs, and should not be recommended as a trajectory target.

Valve exchange towards an adjustable differential pressure valve with gravitational unit, clinical outcome of a single-center study

OBJECTIVE

Overdrainage in children is a long-term problem for shunted patients which might lead to chronic anatomical changes. In order to prevent these problems, valve exchange is performed on a regular basis in patients without hydrostatic units towards a valve with both an adjustable and a gravitational unit. The clinical outcome of these patients is reported in a retrospective study.

METHODS

Between 2009 and 2014, the in-house database was analyzed for patients who received a valve exchange towards an adjustable differential pressure valve with gravitational unit. The study protocol included the patients shunt history, image analysis for ventricular width, and necessity of revision surgery after valve exchange. A questionnaire was sent to the patients in order to ask for their subjective experience for symptom changes and treatment experience.

RESULTS

Forty-six patients were identified (26 girls, mean age 11.8 ± 6.1 years) with a mean follow-up of 36.3 ± 15 months. The ventricular width did increase after valve exchange as measured in frontal and occipital horn ratio (0.364 ± 0.032 vs. 0.402 ± 0.09, p = 0.0017). Of the patients suffering from acute symptoms, 89% improved after treatment. The shunt and valve survival rates were 88 and 95%, respectively, after 12 months. Comparing the total amount of revisions before and after valve exchange, a significant reduction was seen in total but a no significant difference was analyzed in amount of revisions to time ratio.

CONCLUSION

Valve exchange might be cautiously decided if patients seem to perform clinically well. In our study, we were able to show that the strategy of valve exchange to prevent chronic overdrainage is well tolerated and seem to improve patient's clinical outcome in terms of ventricular width, symptom relieve, and revision rate.

Optical Neuronavigation without Rigid Head Fixation During Awake Surgery

OBJECTIVE

Optical neuronavigation without rigid pin fixation of the head may lead to inaccurate results because of the patient's movements during awake surgery. In this study, we report our results using a skull-mounted reference array for optical tracking in patients undergoing awake craniotomy for eloquent gliomas.

METHODS

Between March 2013 and December 2014, 18 consecutive patients (10 men, 8 women) with frontotemporal (n = 16) or frontoparietal (perirolandic; n = 2) lesions underwent awake craniotomy without rigid pin fixation. All patients had a skull-mounted reference array for optical tracking placed on the forehead. Accuracy of navigation was determined with pointer tip deviation measurements on superficial and bony anatomic structures. Good accuracy was defined as a tip deviation <2 mm.

RESULTS

Gross total resection (>98%) was achieved in 7 patients (38%); >90% of tumor was resected in 8 patients (44%). In 3 patients, only subtotal resection or biopsy was performed secondary to stimulation results. In all patients, good accuracy of the optical neuronavigation system could be demonstrated without intraoperative peculiarities or complications. The reference array had to be repositioned because of loosening in 1 patient. Neuronavigation could be reliably applied to support stimulation-based resection.

CONCLUSIONS

A skull-mounted reference array is a simple and safe method for optical neuronavigation tracking without rigid pin fixation of the patient's head.

Ventricular catheter development: past, present, and future

Cerebrospinal fluid diversion via ventricular shunting is the prevailing contemporary treatment for hydrocephalus. The CSF shunt appeared in its current form in the 1950s, and modern CSF shunts are the result of 6 decades of significant progress in neurosurgery and biomedical engineering. However, despite revolutionary advances in material science, computational design optimization, manufacturing, and sensors, the ventricular catheter (VC) component of CSF shunts today remains largely unchanged in its functionality and capabilities from its original design, even though VC obstruction remains a primary cause of shunt failure. The objective of this paper is to investigate the history of VCs, including successful and failed alterations in mechanical design and material composition, to better understand the challenges that hinder development of a more effective design.

Calvarial slope affecting accuracy of Ghajar Guide technique for ventricular catheter placement

OBJECT The Ghajar Guide technique is used to direct a ventricular catheter at a 90° angle to the skull surface at Kocher's point. However, the human calvaria is not completely spherical. Lateral to the sagittal midline, the calvaria slopes downward with individual variation and thereby affects the accuracy of ventricular catheter placement. Accordingly, the authors investigated the accuracy of the orthogonal catheter trajectory using radiographic simulation and examined the effect of the calvarial slope on this accuracy. METHODS A catheter trajectory orthogonal to the skull surface at Kocher's point and the ideal catheter trajectory to the foramen of Monro were drawn bilaterally on coronal head images of 52 patients with hydrocephalus. The correction angle, the difference between the 2 catheter trajectories, was then measured. Meanwhile, the calvarial slope was measured around Kocher's point by using a coronal head image. The correlation between the correction angle and factors such as the calvarial slope and bicaudate index was then assessed using a Pearson correlation analysis. RESULTS The ventricular catheter trajectory orthogonal to the skull at Kocher's point in the patients with hydrocephalus led to a catheter trajectory into the ipsilateral (70.2%) or contralateral (29.8%) lateral ventricles. The correction angles ranged from -3.3° to 16.4° (mean ± SD 5.7° ± 3.7°). In 87 (83.7%) head sides, lateral deviation from the orthogonal trajectory was required to approximate the ideal trajectory, and the correction angle ranged from 2.0° to 16.4° (mean 6.7° ± 2.9°). The calvarial slope in the 104 head sides ranged from 15.6° to 32.5° (mean 24.2° ± 3.1°). Pearson correlation analysis revealed a strong positive correlation (r = 0.733) between the calvarial slope and the correction angle. CONCLUSIONS The accuracy of ventricular catheter placement using the Ghajar Guide technique is affected primarily by the calvarial slope around Kocher's point. A radiographic analysis of a preoperative coronal head image can be used to estimate the accuracy of ventricular catheter placement and enable adjustment to approximate the ideal catheter trajectory.