External ventricular drain insertion accuracy: is there a need for change in practice?

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.

Ventriculoperitoneal shunt entry points in patients undergoing shunt placement: A single-center study

Background

The ventriculoperitoneal (VP) shunt redirects cerebrospinal fluid flow, with the selection of entry points crucial for optimal outcomes. Anatomical landmarks and specific entry points, such as Kocher's, Frazier's, Keen's, and Dandy's points, have been utilized for shunt catheter placement. This study investigates the impact of various entry points on outcomes, particularly the necessity for revision procedures, in patients undergoing VP shunt placement.

Methods

In this retrospective cohort study, we analyzed data from patients in our center's database, collected from October 2017 to October 2022. Participants were classified based on ventriculoperitoneal shunt entry points. The study followed STROBE guidelines. Continuous variables were presented as means with standard deviations (SD) and categorical variables as frequencies and percentages. Linear Model ANOVA and Pearson's Chi-squared tests were used for comparisons. Data analysis was conducted using Jamovi software.

Results

Our study included 94 patients who underwent shunt procedures. The patients were categorized into four treatment groups: Dandy point (10), Frazier point (21), Keen point (43), and Kocher point (20).

Conclusion

Our study found no significant differences in age, FOHR, and indication for shunt placement among catheter entry point subgroups. However, gender distribution, catheter length, and catheter tip location significantly varied. The proportion of patients requiring revision surgery varied among the groups, with the highest rate in the Dandy point group and the lowest in the Keen group; however, the difference among the entry groups was insignificant.

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.

Single institution series describing external ventricular drain (EVD) placement and short- and long-term complications related to placement accuracy

Background

The placement of an external ventricular drain (EVD) for the treatment of acute hydrocephalus is one of the most common life-saving procedures that neurosurgeons perform worldwide. There are many well-known complications associated with EVD placement, including tract hemorrhages, intra-parenchymal and subdural hemorrhages, infection, and catheter misplacement. Given the variety of complications associated with EVD placement and the inconsistent findings on the relationship of accuracy to complications, the present study reviewed short- and long-term complications related to EVD placement at our institution.

Methods

A retrospective review was conducted for all consecutive patients who underwent bedside EVD placement for any indication between December 2020 and December 2021. Collected variables included demographic information, etiology of disease state, pre-and post-operative head computed tomography measurements, and post-procedural metrics (immediate and delayed complications).

Results

A total of 124 patients qualified for inclusion in our study. EVDs that were non-functioning/exchanged were not significantly related to age, accuracy, ventriculomegaly, sex, disposition, laterality, type of EVD used, intraventricular hemorrhage (IVH), etiology, or Kakarla Grade (KG) (all P > 0.17). The need for a second EVD was similarly not related to age, accuracy, ventriculomegaly, sex, disposition, location, laterality, type of EVD used, IVH, etiology, or KG (all P > 0.130). Patients who died, however, were significantly more likely to have a second contralateral EVD placed (18.2% vs. 4.9% P = 0.029). We also found that left-sided EVDs were significantly more likely to fail within seven days of placement (29.4% vs 13.3%, P = 0.037; relative risk (RR) 1.93, 95% confidence interval: 1.09-3.43), unrelated to age, sex, etiology, type of EVD, IVH, location of the procedure, or accuracy (all P > 0.07). This remained significant when using a binary logistic regression to control for ventriculomegaly, accuracy, mortality, age, sex, and etiology (P = 0.021, B = 3.43).

Conclusion

In our cohort, although a clear relationship between inaccuracy and complication rates was not found, our data did demonstrate that left-sided EVDs were more likely to fail within the immediate postoperative time point, and patients who died were more likely to have a second, contralateral EVD placed.

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.

Neurosurgical simulation models developed in Latin America and the Caribbean: a scoping review

Simulation training is an educational tool that provides technical and cognitive proficiency in a risk-free environment. Several models have recently been presented in Latin America and the Caribbean (LAC). However, many of them were presented in non-indexed literature and not included in international reviews. This scoping review aims to describe the simulation models developed in LAC for neurosurgery training. Specifically, it focuses on assessing the models developed in LAC, the simulated neurosurgical procedures, the model's manufacturing costs, and the translational outcomes. Simulation models developed in LAC were considered, with no language or time restriction. Cadaveric, ex vivo, animal, synthetic, and virtual/augmented reality models were included for cranial and spinal procedures. We conducted a review according to the PRISMA-ScR, including international and regional reports from indexed and non-indexed literature. Two independent reviewers screened articles. Conflicts were resolved by a third reviewer using Covidence software. We collected data regarding the country of origin, recreated procedure, type of model, model validity, and manufacturing costs. Upon screening 917 studies, 69 models were developed in LAC. Most of them were developed in Brazil (49.28%). The most common procedures were related to general neurosurgery (20.29%), spine (17.39%), and ventricular neuroendoscopy and cerebrovascular (15.94% both). Synthetic models were the most frequent ones (38.98%). The manufacturing cost ranged from 4.00 to 2005.00 US Dollars. To our knowledge, this is the first scoping review about simulation models in LAC, setting the basis for future research studies. It depicts an increasing number of simulation models in the region, allowing a wide range of neurosurgical training in a resource-limited setting.

High-Accuracy Neuro-Navigation with Computer Vision for Frameless Registration and Real-Time Tracking

For the past three decades, neurosurgeons have utilized cranial neuro-navigation systems, bringing millimetric accuracy to operating rooms worldwide. These systems require an operating room team, anesthesia, and, most critically, cranial fixation. As a result, treatments for acute neurosurgical conditions, performed urgently in emergency rooms or intensive care units on awake and non-immobilized patients, have not benefited from traditional neuro-navigation. These emergent procedures are performed freehand, guided only by anatomical landmarks with no navigation, resulting in inaccurate catheter placement and neurological deficits. A rapidly deployable image-guidance technology that offers highly accurate, real-time registration and is capable of tracking awake, moving patients is needed to improve patient safety. The Zeta Cranial Navigation System is currently the only non-fiducial-based, FDA-approved neuro-navigation device that performs real-time registration and continuous patient tracking. To assess this system's performance, we performed registration and tracking of phantoms and human cadaver heads during controlled motions and various adverse surgical test conditions. As a result, we obtained millimetric or sub-millimetric target and surface registration accuracy. This rapid and accurate frameless neuro-navigation system for mobile subjects can enhance bedside procedure safety and expand the range of interventions performed with high levels of accuracy outside of an operating room.

Accuracy, Hemorrhagic Complications and CT Radiation Dose of Emergency External Ventricular Drain (EVD) Placement in Pediatric Patients: A 15-Year Retrospective Analysis

PURPOSE

To assess accuracy, the frequency of hemorrhagic complications and computed tomography (CT) radiation dose parameters in pediatric patients undergoing landmark-guided external ventricular drain (EVD) placement in an emergency setting.

METHODS

Retrospective analysis comprised 36 EVD placements with subsequent CT control scans in 29 patients (aged 0 to 17 years) in our university hospital from 2008 to 2022. The position of the EVD as well as the presence and extension of bleeding were classified according to previously established grading schemes. Dose length product (DLP), volume-weighted CT dose index (CTDIvol) and scan length were extracted from the radiation dose reports and compared to the diagnostic reference values (DRLs) issued by the German Federal Office for Radiation Protection.

RESULTS

After the initial EVD placement, optimal positioning of the catheter tip into the ipsilateral frontal horn or third ventricle (Grade I), or a functional positioning in the contralateral lateral ventricle or the non-eloquent cortex (Grade II), was achieved in 28 and 8 cases, respectively. In 32 of 36 procedures, no evidence of hemorrhage was present in the control CT scan. Grade 1 (<1 mL) and Grade 2 (≥1 to 15 mL) bleedings were detected after 3 and 1 placement(s), respectively. For control scans after EVD placements, CTDIvol (median [25%; 75% quartile]) was 39.92 [30.80; 45.55] mGy, DLP yielded 475.50 [375.00; 624.75] mGy*cm and the scan length result was 136 [120; 166] mm. Exceedances of the DRL values were observed in 14.5% for CTDIvol, 12.7% for DLP and 65.6% for the scan length. None of these values was in the range requiring a report to the national authorities.

CONCLUSION

Landmark-based emergency EVD placement in pediatric patients yielded an optimal position in most cases already after the initial insertion. Complications in terms of secondary hemorrhages are rare. CT dose levels associated with the intervention are below the reportable threshold of the national DRLs in Germany.

External ventricular drains and risk of freehand placement: A systematic review and meta-analysis

OBJECTIVE

External ventricular drains (EVDs) are used to monitor and treat elevated intracranial pressure. EVDs are often placed blindly without the use of imaging guidance, and successful placement with respect to pass attempts and final catheter location may suffer as a result of this freehand technique.

METHODS

A systematic literature search was conducted in PubMed, Embase, Web of Science, and Cochrane databases to identify studies pertaining to freehand EVD placement through March 30, 2022. Studies were included if they reported percentage of EVDs placed successfully on the first pass attempt, or final catheter location as defined by the Kakarla Grading System. Pooled weighted incidence estimates and 95% confidence intervals (95%CI) were calculated using a random effects model.

RESULTS

Of the 2964 results returned from the literature search, 39 studies were included in this meta-analysis. These studies reported on 6313 EVDs placed via freehand technique in 6070 patients with the following respective incidence: successful EVD placement on the first attempt (78%, 95%CI: 67-86%); placement with a Kakarla Grade of 1 (optimal location) (72%, 95%CI: 66-77%); hemorrhage (7%, 95%CI: 6-10%), and infection (5%, 95%CI: 3-8%).

CONCLUSIONS

Only 78% of EVDs in this meta-analysis were placed successfully on the first pass, and only 72% of final placements were deemed optimal. This represents a relatively high rate of suboptimal outcomes with respect to EVD placement, which could potentially be avoided with the use of navigation-assisted placement techniques.

Intraoperative ultrasound is valuable for detecting intracranial hematoma progression and decreasing mortality in traumatic brain injury

BACKGROUND

Our aim was to explore the clinical benefit of intraoperative ultrasound in decompressive craniectomy (DC) for traumatic brain injury (TBI).

METHODS

From January 1, 2018, through April 30, 2021, 54 patients who developed acute subdural hematoma (SDH) due to blunt injury and underwent DC with or without intraoperative ultrasound assistance were retrospectively included in our study. Logistic regression analyses were performed to compare the therapeutic efficacy in the two groups.

RESULTS

In the ultrasound group (14 patients, 25.93%), intraoperative ultrasound was used for assisting hematoma removal and/or ventriculostomy during DC. In the control group (40 patients, 74.07%), ultrasound was not used during the operation and ventriculostomy was not performed. No statistically significant differences in age, sex, initial Glasgow Coma Scale (GCS) score, blood loss, postoperative intracranial pressure (ICP), duration of hyperosmolar therapy, or Glasgow Outcome Scale Extended (GOS-E) score 6 months after injury were observed. No mortality was recorded in the ultrasound group. The mortality rate in the control group during hospitalization was 25% (p < 0.05).

CONCLUSIONS

Intraoperative ultrasound is helpful for intracranial hematoma removal and ventriculostomy with cerebrospinal fluid drainage and decreases mortality in experienced hands. The reason for higher mortality rate in the control group might result from poor hematoma clearance rate and poor postoperative intracranial pressure control. It is a useful tool for diagnosing and assisting with treatment in cases of TBI.

A Bibliometric Analysis of the Top 50 Most Influential Articles on External Ventricular Drains

OBJECTIVE

External ventricular drains (EVDs) are commonly used to remove cerebrospinal fluid and monitor intracranial pressure in patients with neurological dysfunction. Often the first invasive procedure learned in training, ventricular drain placement is the quintessential neurosurgical procedure. This bibliometric analysis highlights the top contributing EVD articles in current evidence-based practice.

METHODS

The Scopus database was used to perform a title-specific, keyword-based search for all publications until September 2022. The keywords "external ventricular drain" or "EVD" or "external ventriculostomy" were used. The 50 most cited articles were selected for analysis. Parameters included the following: title, citation count, citations per year, authors, specialty of first author, institution, country of origin, publishing journal, Source Normalized Impact per Paper, and Hirsch index.

RESULTS

The keyword-based search showed that 8464 articles on EVDs were published between 1991 and 2022. The top 50 articles were published between 1999 and 2019. The top 50 articles acquired a total of 3343 citations with an average of 66.86 citations per paper. The rate of self-citations accounted for an average of 5.16% of the total number of citations. A majority of the top 50 articles focused on EVD infection and placement accuracy. The first and second most cited papers were authored by Zabramski et al and Fried et al, respectively.

CONCLUSIONS

The bibliometric analysis provides a quantitative overview of how topics and interventions are analyzed in academic medicine. In the present study, we evaluated the global trends in EVDs by analyzing the top 50 most cited papers.

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.

Development of an ultrafast brain MR neuronavigation protocol for ventricular shunt placement

OBJECTIVE

Advancements in MRI technology have provided improved ways to acquire imaging data and to more seamlessly incorporate MRI into modern pediatric surgical practice. One such situation is image-guided navigation for pediatric neurosurgical procedures, including intracranial catheter placement. Image-guided surgery (IGS) requires acquisition of CT or MR images, but the former carries the risk of ionizing radiation and the latter is associated with long scan times and often requires pediatric patients to be sedated. The objective of this project was to circumvent the use of CT and standard-sequence MRI in ventricular neuronavigation by investigating the use of fast MR sequences on the basis of 3 criteria: scan duration comparable to that of CT acquisition, visualization of ventricular morphology, and image registration with surface renderings comparable to standard of care. The aim of this work was to report image development, implementation, and results of registration accuracy testing in healthy subjects.

METHODS

The authors formulated 11 candidate MR sequences on the basis of the standard IGS protocol, and various scan parameters were modified, such as k-space readout direction, partial k-space acquisition, sparse sampling of k-space (i.e., compressed sensing), in-plane spatial resolution, and slice thickness. To evaluate registration accuracy, the authors calculated target registration error (TRE). A candidate sequence was selected for further evaluation in 10 healthy subjects.

RESULTS

The authors identified a candidate imaging protocol, termed presurgical imaging with compressed sensing for time optimization (PICO). Acquisition of the PICO protocol takes 25 seconds. The authors demonstrated noninferior TRE for PICO (3.00 ± 0.19 mm) in comparison with the default MRI neuronavigation protocol (3.35 ± 0.20 mm, p = 0.20).

CONCLUSIONS

The developed and tested sequence of this work allowed accurate intraoperative image registration and provided sufficient parenchymal contrast for visualization of ventricular anatomy. Further investigations will evaluate use of the PICO protocol as a substitute for CT and conventional MRI protocols in ventricular neuronavigation.

A nationwide prospective multicenter study of external ventricular drainage: accuracy, safety, and related complications

OBJECTIVE

External ventricular drainage (EVD) catheters are associated with complications such as EVD catheter infection (ECI), intracranial hemorrhage (ICH), and suboptimal placement. The aim of this study was to investigate the rates of EVD catheter complications and their associated risk factor profiles in order to optimize the safety and accuracy of catheter insertion.

METHODS

A total of 348 patients with urgently placed EVD catheters were included as a part of a prospective multicenter observational cohort. Strict definitions were applied for each complication category.

RESULTS

The rates of misplacement, ECI/ventriculitis, and ICH were 38.6%, 12.2%, and 9.2%, respectively. Catheter misplacement was associated with midline shift (p = 0.002), operator experience (p = 0.031), and intracranial length (p < 0.001). Although mostly asymptomatic, ICH occurred more often in patients receiving prophylactic low-molecular-weight heparin (LMWH) (p = 0.002) and those who required catheter replacement (p = 0.026). Infectious complications (ECI/ventriculitis and suspected ECI) occurred more commonly in patients whose catheters were inserted at the bedside (p = 0.004) and those with smaller incisions (≤ 1 cm) (p < 0.001). ECI/ventriculitis was not associated with preinsertion antibiotic prophylaxis (p = 0.421), catheter replacement (p = 0.118), and catheter tunneling length (p = 0.782).

CONCLUSIONS

EVD-associated complications are common. These results suggest that the operating room setting can help reduce the risk of infection, but not the use of preoperative antibiotic prophylaxis. Although EVD-related ICH was associated with LMWH prophylaxis for deep vein thrombosis, there were no significant clinical manifestations in the majority of patients. Catheter misplacement was associated with operator level of training and midline shift. Information from this multicenter prospective cohort can be utilized to increase the safety profile of this common neurosurgical procedure.

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.

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.

Analysis of a Novel Entry Point for Freehand Ventriculostomy Using Computerized Tomography Scans

Background

External ventricular drain (EVD) placement is one of the most common procedures in neurosurgery. Neurosurgeons generally prefer to access the ventricles via Kocher’s point since it is the most common point of entry to this area; however, this point is used to describe different anatomic landmarks and is not well-defined.

Objective

The present study aims to describe and provide an anatomical assessment of a novel ventriculostomy access point developed by the authors using computerized tomography (CT) scans performed on 100 patients.

Materials and methods

Data were collected from 100 randomly selected patients with normal ventricular anatomy found on their 1.0 mm-slice CT scans performed at the Burdenko Neurosurgical Center from March 2019 to June 2021. The CT inclusion criteria were: CT slices < or = to 1 mm and absence of brain herniation. Patients with brain mass lesions, severe brain edema, and pneumocephalus were excluded. Age, gender, and ventricular size were not exclusion criteria.

Results

The mean patient age was 43.58 years (range 4-73), with 50 men and 50 women. The mean Evan’s index was 25.7 % (SD=4.38 %, range 10.2-41.0 %). No differences were found between the angles of EVD placement on either side (89.50±1.22 degrees on the right and 89.60±1.14 degrees on the left). Hence, nearly all EVD cases had been placed perpendicularly to the skull surface at a pinpoint location.

Conclusion

The proposed point of successful ventriculostomy placement in this study was 3 cm from the bregma along the coronal suture. The angle of EVD placement was approximately 90 degrees in almost all patients and was independent of the patient’s age and the side of the head that was entered. Little correlation was found between the value of the entry angle and Evan’s index. The point is simply identifiable, and its entry is easily accessible in practice.

Freehand frontal external ventricular drain (EVD) placement: Accuracy and complications

Ventriculostomy placement is a life-saving procedure. Our aim was to determine the predictors of inaccurate placement, our infection and hemorrhage rate. This was a retrospective study of EVD placements between January - November 2019. Data related to hemorrhage, infection and catheter misplacement were collected. Univariate and multivariate analyses of predictors of suboptimal catheter placement were performed. 131 consecutive patients underwent freehand EVD placement. The indications were subarachnoid hemorrhage in 36 (27.5%) patients, hemorrhagic stroke in 36 (27.5%), and trauma in 32 (24.4%) patients. Nine patients (6.8%) had culture-proven CSF bacterial infection. Sixteen (12.2%) patients developed small tract hemorrhage, while 8 (6.1%) patients developed large intraparenchymal hemorrhage. There was no correlation between tract hemorrhage or large hemorrhage with the use of antiplatelet or anticoagulation medicines on presentation, diagnosis or Kakarla grade. Trauma diagnosis (odds ratio 2.59, p-value 0.05), left side of EVD placement (odds ratio 2.84, p-value 0.03), increasing midline shift (odds ratio 1.09, p-value 0.03), and lower bicaudate index (odds ratio 0.56, p-value 0.02) were all predictors of Kakarla grade 3 suboptimal placement. When Kakarla grade 2 and 3 were combined, similar results were obtained except that midline shift was no longer statistically significant. The multivariable regression model predicting Kakarla 3 suboptimal placement revealed that low bicaudate index and left sided EVD were predictors of misplaced EVD.

Systematic review and meta-analysis of external ventricular drain placement accuracy and narrative review of guidance devices

BACKGROUND

Insertion of external ventricular drain (EVD) is one of the most common neurosurgical procedures performed worldwide. This is generally performed freehand, on the basis of anatomical landmarks. There is significant variability in the reported accuracy of freehand placement, lacking Level I evidence. We present the first meta-analysis of freehand EVD placement accuracy and technologies or techniques to enhance accuracy.

METHODS

We report a systematic review of the Pubmed, Embase, and Cochrane Central databases according to MOOSE (Meta-analysis Of Observational Studies) guidelines. 37 studies were included for qualitative analysis and 19 studies (2983 cases) for quantitative analysis.

RESULTS

There is substantial heterogeneity in the outcome measures used to report EVD placement accuracy. Of those nineteen studies reporting accuracy using the Kakarla grading system the mean rate of ideal ipsilateral frontal horn placement was 73% (standard deviation ±7%). The use of formal stereotaxic guidance is consistently reported to improve accuracy to >90%, although with variable outcome measures. However, the reported efficacy of other guidance devices or techniques is highly variable. The quality of studies directly comparing all existing non-stereotaxic devices with freehand EVD placement is poor and precludes any assertion of superiority to freehand insertion.

CONCLUSIONS

We provide the first meta analysis of freehand placement accuracy. There is insufficient data to perform a meta-analysis of the relative efficacy of interventions to improve accuracy. Qualitative synthesis of reports of stereotaxic guidance is suggestive of higher accuracy than freehand placement.

Orthogonal external ventricular drain (EVD) trajectory from burr holes sited by junior neurosurgical staff is superior to freehand placement: An in-silico model

External ventricular drain (EVD) or ventriculostomy placement is one of the most common neurosurgical procedures performed worldwide and is associated with complications including haemorrhage, malposition and infection. Several authors have attempted to define an ideal trajectory for placement, and scalp-mounted guidance devices have been devised to exploit the theoretical ideal orthogonal trajectory from the scalp to the lateral ventricles. However, uptake has been limited due to lack of demonstrated superiority to freehand placement. Previous modelling studies have failed to include a true-to-life sample of patients undergoing EVD insertion and excluded cases with midline shift or non-hydrocephalus indications. Further, none have attempted to model the orthogonal insertion of EVD via actual burr holes placed by junior neurosurgical staff. In our report of 58 cases of frontal EVD insertion in a low-volume Australian neurosurgical unit freehand EVD insertion resulted in acceptable placement in the ipsilateral frontal horn in 62% of cases, any ventricle in 22%, and in eloquent or non-eloquent brain in 16% of cases. The modelled orthogonal trajectory from the same burr holes, using post-procedural computed tomography scans and the S8 Stealth Station (Medtronic), resulted in superior placement; 80% in the ipsilateral frontal horn and 20% contralateral (p = 0.007). There were no significant malpositions associated with the modelled trajectories. In our series, 18% of freehand catheters required multiple placement attempts. In conclusion, our data suggests that an orthogonal trajectory may result in improved EVD positioning compared to freehand placement.

Utility of image-guided external ventriculostomy: analysis of contemporary practice in the United Kingdom and Ireland

OBJECTIVE

Freehand external ventricular drain (EVD) insertion is associated with a high rate of catheter misplacement. Image-guided EVD placement with neuronavigation or ultrasound has been proposed as a safer, more accurate alternative with potential to facilitate proper placement and reduce catheter malfunction risk. This study aimed to determine the impact of image-guided EVD placement on catheter tip position and drain functionality.

METHODS

This study is a secondary analysis of a data set from a prospective, multicenter study. Data were collated for EVD placements undertaken in the United Kingdom and Ireland from November 2014 to April 2015. In total, 21 large tertiary care academic medical centers were included.

RESULTS

Over the study period, 632 EVDs were inserted and 65.9% had tips lying free-floating in the CSF. Only 19.6% of insertions took place under image guidance. The use of image guidance did not significantly improve the position of the catheter tip on postoperative imaging, even when stratified by ventricular size. There was also no association between navigation use and drain blockage.

CONCLUSIONS

Image-guided EVD placement was not associated with an increased likelihood of achieving optimal catheter position or with a lower rate of catheter blockage. Educational efforts should aim to enhance surgeons' ability to apply the technique correctly in cases of disturbed cerebral anatomy or small ventricles to reduce procedural risks and facilitate effective catheter positioning.

Comparison of a bolt-connected external ventricular drain with a tunneled external ventricular drain - a narrative review and meta-analysis

External ventricular drain (EVD) is one of the most commonly performed neurosurgical procedures. EVD can be associated with high rates of complications like misplacement, iatrogenic hemorrhage, and CSF infection. Several modifications have been proposed in the EVD insertion techniques to decrease the risk of these complications. Bolt-connected EVD, one of these modifications which involves insertion of a bolt in the burr hole, has been proposed to have better chances of optimal placement of EVD tip, lesser risk of CSF infection, and accidental pullout. A comprehensive search of different databases was performed to retrieve studies comparing the bolt-connected EVD with tunneled EVD and meta-analysis was done. Seven studies met inclusion criteria and were included in the meta-analysis. Our analysis revealed that bolt-connected EVD is associated with significantly better chances of optimal placement than traditional tunneled EVD (MH OR-1.65, 95% CI 1.14 to 2.40, p = 0.008). We also observed that bolt-connected EVD is associated with significantly decreased risk of CSF infection (MH OR-0.60, 95% CI 0.39 to 0.94, p = 0.026), EVD malfunction (MH OR-0.31, 95% CI 0.16 to 0.58, p = 0.0003), and accidental disconnection (MH OR-0.09, 95% CI 0.03 to 0.26, p < 0.0001) as compared to traditional tunneled EVD. The difference between the two techniques was not statistically significant for complications, multiple punctures done for insertion of EVD, iatrogenic intracranial, and need of reoperation. Bolt-connected external ventricular drain is associated with significantly more chances of optimal placement and lesser chances of accidental discontinuation and CSF infection than tunneled EVD. There was no statistically significant difference noted between the two techniques for multiple punctures done for insertion of EVD, iatrogenic intracranial hemorrhage and need of reoperation. However, most of the included studies were retrospective. Thus, the results from the meta-analysis should be interpreted with caution as further prospective high-quality studies are needed.

The Clinical Application of Robot-Assisted Ventriculoperitoneal Shunting in the Treatment of Hydrocephalus

Background

This work aims to assess the effectiveness and safety of robotic assistance in ventriculoperitoneal shunting and to compare the results with data from traditional surgery.

Methods

We retrospectively analyzed 60 patients who had undergone ventriculoperitoneal shunting, of which shunts were implanted using a robot in 20 patients and using traditional surgical methods in the other 40 patients. Data related to surgery were compared between the two groups, and the accuracy of the drainage tube in the robot-assisted group was assessed.

Results

In the robot-assisted surgery group, the operation duration was 29.75 ± 6.38 min, intraoperative blood loss was 10.0 ± 3.98 ml, the success rate of a single puncture was 100%, and the bone hole diameter was 4.0 ± 0.3 mm. On the other hand, the operation duration was 48.63 ± 6.60 min, intraoperative blood loss was 22.25 ± 4.52 ml, the success rate of a single puncture was 77.5%, and the bone hole diameter was 11.0 ± 0.2 mm in the traditional surgery group. The above are statistically different between the two groups (P < 0.05). Only one case of surgery-related complications occurred in the robot-assisted group, while 13 cases occurred in the traditional surgery group. There was no significant difference in the hospitalization time. In the robot-assisted surgery group, the average radial error was 2.4 ± 1.5 mm and the average axial error was 1.9 ± 2.1 mm.

Conclusion

In summary, robot-assisted implantation is accurate, simple to operate, and practical; the duration of surgery is short; trauma to the patient is reduced; and fewer postoperative complications related to surgery are reported.

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.

Multimodal Simulation of a Novel Device for a Safe and Effective External Ventricular Drain Placement

Background

External ventricular drain (EVD) placement is mandatory for several pathologies. The misplacement rate of the EVD varies widely in literature, ranging from 12.3 to 60%. The purpose of this simulation study is to provide preliminary data about the possibility of increasing the safety of one of the most common life-saving procedures in neurosurgery by testing a new device for EVD placement.

Methods

We used a novel guide for positioning the ventricular catheter (patent RM2014A000376). The trajectory was assessed using 25 anonymized head CT scans. The data sets were used to conduct three-dimensional computer-based and combined navigation and augmented reality-based simulations using plaster models. The data set inclusion criteria were volumetric head CT scan, without midline shift, of patients older than 18. Evans' index was used to quantify the ventricle's size. We excluded patients with slit ventricles, midline shift, skull fractures, or complex skull malformations. The proximal end of the device was tested on the cadaver.

Results

The cadaveric tests proved that a surgeon could use the device without any external help. The multimodal simulation showed Kakarla grade 1 in all cases but one (grade 2) on both sides, after right and left EVD placement. The mean Evans' index was 0.28. The geometric principles that explain the device's efficacy can be summarized by studying the properties of circumference and chord. The contact occurs, for each section considered, at the extreme points of the chord. Its axis, perpendicular to the plane tangent to the spherical surface at the entry point, corresponds to the direction of entry of the catheter guided by the instrument.

Conclusion

According to our multimodal simulation on cadavers, 3D computer-based simulation, 3D plaster modeling, 3D neuronavigation, and augmented reality, the device promises to offer safer and effective EVD placement. Further validation in future clinical studies is recommended.

Freehand external ventricular drain insertion - is there a learning curve?

Background:

Accuracy of freehand insertion of external ventricular drains (EVDs) is influenced by many factors including etiology and presence of midline shift. We sought to assess if junior neurosurgical trainees’ performance in accurately inserting EVDs improves with experience, using a radiological grading system.

Methods:

EVD insertion procedures from the first 3 years of training were identified from the operative logbooks of three trainees. Postoperative CT head scans were graded for accuracy of placement and intraventricular catheter length.

Results:

40 frontal EVDs performed primarily by the trainees were identified, after 34 assists, revision surgeries, parietal, or occipital insertions were excluded from the study. The mean number (±1 SD) of procedures was 7.7 ± 4.5 at ST3, 4.7 ± 2.5 at ST2, and 1 ± 1 at ST1. About 80% of EVDs were optimally inserted. There was no statistically significant difference in placement accuracy between the three training grades (P = 0.669), nor any difference in intraventricular catheter length (P = 0.697). There were no statistically significant differences between surgeons’ accuracy at each grade.

Conclusion:

We report good accuracy of EVDs tip position inserted by junior neurosurgery trainees. Trainees perform more procedures independently as they progress in their career. Further studies including senior years of training performance, other procedure factors and outcome should be considered.

Accuracy of bolt external ventricular drain insertion by neurosurgeons of different experience

OBJECTIVE

The accuracy of tunneled external ventricular drain (EVD) placement has been shown to be similar among practitioners of varying experience, but this has not yet been investigated for bolt EVDs. Tunneled and bolt EVDs are distinct techniques, and it is unclear if conclusions regarding accuracy can be inferred from one method to the other. The goal of this study was to determine whether neurosurgical experience influences the accuracy of bolt EVD placement.

METHODS

We performed a single-center retrospective analysis of accuracy of bolt EVD placement between 1st December 2018 and 31st May 2020, comparing the accuracy outcomes between three levels of training (junior trainees (JT); mid-grade trainees (MT); senior trainees/fellows (ST)). Accuracy was determined radiologically by two methods: Kakarla grade and by measuring the distance of the catheter tip to its optimal position (DTOP) at the foramen of Monro.

RESULTS

Eighty-seven patients underwent insertion of bolt EVDs, of which n = 19 by JT, n = 40 by MT and n = 28 by ST, with a significant difference found between training grades in the median Kakarla grade (p = 0.0055) and in the accuracy of placement as per DTOP (p = 0.0168).

CONCLUSIONS

In contrast to previous published results on tunneled EVDs, we demonstrate that the accuracy of bolt EVD placement is dependent on neurosurgical experience. Our results draw awareness to the fact that the bolt EVD technique can represent a challenge for less experienced practitioners and underline the importance of dedicated training to support the safe insertion of bolt ventricular catheters.

Determinants of accuracy of freehand external ventricular drain placement by neurosurgical trainees

BACKGROUND

The external ventricular drain (EVD) placement is one of the most common neurosurgical procedures. This operation is performed by freehand technique in the majority of cases; therefore, the operator's experience plays an important role in success and possible morbidity of this procedure.

OBJECTIVE

To evaluate the accuracy and safety of EVD placement by junior neurosurgery residents and factors predicting accuracy of EVD placement.

METHODS

This is a prospective cohort study conducted at our academic medical center, between September 2017 and August 2018. All patients 18 years or older who required EVD placement were included. The accuracy and complications of EVD placement were assessed in the first and second year resident cohorts as well as by their level of experience, using descriptive statistics. Univariate and multivariate models were used to assess predictive factors for optimal EVD.

RESULTS

A total of 100 EVDs were placed in 100 patients during the study period. According to Kakarla classification, the catheter was optimally placed in 80% of cases. The first year residents had a significantly higher rate of suboptimal burr hole placement compared to the second year residents (66.7% versus 27.1%, p = 0.004). The trainees with less than 10 EVD placement experience also had a significantly higher rate of suboptimal burr hole placement (55.2% vs. 23.9%, p = 0.003), significantly longer duration of operation (43.1 min ± 14.9SD vs 34.2 min ± 9.6 p = 0.005), and significantly lower rate of optimal EVD location (85.9% versus 65.5%, p = 0.023). Optimal location of the burr hole was the only significant predictor of optimal EVD placement in multivariate analysis (OR 11.9, 95% CI 3.2-44.6, p < 0.001).

CONCLUSIONS

Neurosurgery residents experience and optimal burr hole placement are the main predicators of accurate EVD placement.

Complications of external cerebrospinal fluid drainage in aneurysmal subarachnoid haemorrhage

Background

The need for external cerebrospinal fluid (CSF) drains in aneurysmal subarachnoid haemorrhage (aSAH) patients is common and might lead to additional complications.

Objective

A relation between the presence of an external CSF drain and complication risk is investigated.

Methods

A prospective complication registry was analysed retrospectively. We included all adult aSAH patients admitted to our academic hospital between January 2016 and January 2018, treated with an external CSF drain. Demographic data, type of external drain used, the severity of the aSAH and complications, up to 30 days after drain placement, were registered. Complications were divided into (1) complications with a direct relation to the external CSF drain and (2) complications that could not be directly related to the use of an external CSF drain referred to as medical complications

Results

One hundred and forty drains were implanted in 100 aSAH patients. In total, 112 complications occurred in 59 patients. Thirty-six complications were drain related and 76 were medical complications. The most common complication was infection (n = 34). Drain dislodgement occurred 16 times, followed by meningitis (n = 11) and occlusion (n = 9). A Poisson model showed that the mean number of complications raised by 2.9% for each additional day of drainage (95% CI: 0.6–5.3% p = 0.01).

Conclusion

Complications are common in patients with aneurysmal subarachnoid haemorrhage of which 32% are drain-related. A correlation is present between drainage period and the number of complications. Therefore, reducing drainage period could be a target for further improvement of care.

Common Trajectories for Freehand Frontal Ventriculostomy: A Systematic Review

BACKGROUND

Freehand ventriculostomy is one of the most commonly performed neurosurgical procedures. While a variety of approaches have been described, frontal via Kocher's point is the most common. Multiple trajectories have been described, but no consensus exists as to the most efficacious. Our objective was to assess the literature regarding trajectories for frontal ventriculostomy and their associated success rates and complications.

METHODS

We performed a systematic review of the literature, querying the PubMed/MEDLINE database with the search term "(EVD OR extra-ventricular drain OR ventriculostomy OR external ventricular drain) AND (hand OR freehand OR bedside)" and reported the characteristics and findings of both simulation and clinical studies according to trajectory and catheter position. Final catheter tip position was graded on the Kakarla scale.

RESULTS

A total of 198 abstracts were screened; 40 full papers were assessed. Sixteen were included, 11 of which were clinical studies and 5 of which were simulation studies. Six studies coronally targeted the ipsilateral medial epicanthus (IMC), 4 utilized an orthogonal trajectory (P), and 1 targeted the naison (N). Ideal placement (Kakarla grade 1) was achieved in 954 of 1391 (68.58%) procedures when the IMC was targeted versus 243 of 354 (70.43%) when P was targeted. Potentially harmful (Kakarla grade 3) placement was observed in 142 of 1391 (10.21%) procedures when the IMC was targeted and 20 of 345 (5.80%) when P was targeted. All 5 simulation studies found the IMC target to be inferior.

CONCLUSIONS

The IMC is the most prevalent trajectory for frontal ventriculostomy but no target is demonstrably superior. More robust clinical research is required to determine the optimal trajectory.

Optimizing accuracy of freehand cannulation of the ipsilateral ventricle for intracranial pressure monitoring in patients with brain trauma

Background

Intracranial pressure (ICP) monitoring in traumatic brain injury (TBI) usually requires the placement of a catheter into the ipsilateral ventricle. This surgical procedure is commonly performed via a freehand method using surface anatomical landmarks as guides. The current accuracy of the catheter placement remains relatively low and even lower among TBI patients. This study was undertaken to optimize the freehand ventricular cannulation to increase the accuracy for TBI. The authors hypothesized that an optimal surgical plan of cannulation should give an operator the greatest degrees of freedom, which could be measured as the range of operation angle, range of catheter placement depth, and size of the target area.

Methods

An imaging simulation was first performed using the computed tomography (CT) images of 47 adult patients with normal brain anatomy. On the reconstructed 3D head model, four different coronal planes of ventricular cannulation were identified: a 4-cm anterior, a 2-cm anterior, a standard (central), and a 2-cm posterior plane. The degrees of freedom during the cannulation procedure were determined, including the relevant angles, lengths of cannulation, cross-sectional area, and bounding rectangle of the lateral ventricle. Next, a retrospective assessment was performed on the CT scans of another 111 patients with TBI who underwent freehand ventricular cannulation for ICP monitoring. Postoperative measurements were also performed based on CT images to calculate the accuracy and safety of catheter placement between coronal planes in practice.

Results

Our simulation results showed that the 2-cm anterior plane had more extensive degrees of freedom for ventricular cannulation, in terms of length of catheter trajectory (7% longer, P<0.001), cross-sectional area of the lateral ventricle (14% larger, P=0.046), and length of the lateral ventricle (17% wider, P<0.001) than that of the standard plane, while both the 4-cm anterior and 2-cm posterior planes did not offer advantages over the standard plane in these ways. The mean length range of catheter trajectory in the 2-cm anterior plane was 41 to 58 mm. Retrospective assessment of TBI patients with ICP monitor placement also confirmed our simulation data. It showed that the accuracy of ipsilateral ventricle cannulation in the 2-cm anterior plane was 70.6%, which was a significant increase from 42.9% in the standard plane (P=0.007).

Conclusions

Our imaging simulation and retrospective study demonstrate that different coronal planes could provide different degrees of freedom for cannulation, the 2-cm anterior plane has the greatest degrees of freedom in terms of larger target area and greater length range of the trajectory. The optimized surgical plan in this manner could improve cannulation accuracy and benefit a significant number of TBI patients.

High accuracy of external ventricular drainage placement using anatomical landmarks

BACKGROUND

The conventional approach for external ventricular drainage (EVD) application is the freehand method. Technical devices can improve the accuracy of placement, but they have not yet replaced anatomical landmarks owing to the cost and effort that they entail. There is disagreement as to whether freehand EVD application is safe enough to be accepted as a standard technique. Many authors have investigated the final catheter position in retrospect. They describe variable rates of malpositioning. However, few studies have assessed in how far cranial surface anatomy has really been respected during burr-hole drilling and catheter insertion. The aim of this study was to investigate parameters that might play a part in determining the final intracranial catheter position.

METHODS

In all, 100 pre- and postprocedural thin-layer computed-tomography (CT) scans of EVD patients were analysed with the help of JiveX® and OsiriX Lite® software. A series of anatomical and catheter-related parameters, including inter alia intraventricular blood, midline shift, burr-hole location and catheter entrance angle, were correlated with the final catheter position.

RESULTS

A majority of EVDs show an optimal or nearly optimal position. Only the deviation of catheter entrance angle has a significant influence on catheter malpositioning. The burr-hole location can vary within an area of several centimetres around the coronary suture.

CONCLUSIONS

The freehand application of EVD is safe as long as the intracranial anatomy is not disfigured to a large extent, the surface measurements are carried out precisely and the puncturing is done perpendicularly to the skull.

External Ventricular Drain Migration Causing Parinaud's Syndrome: A Case Report

Background: External ventricular drains (EVD) are used for emergent management of acute hydrocephalus and for monitoring of intracranial pressure. Common complications of EVDs include malposition, infection, and hemorrhage. Here, the authors present a novel case of EVD migration causing Parinaud’s syndrome.

Case description: A thirty-three-year-old female presented with witnessed seizure secondary to a left supraclinoid internal carotid artery aneurysm and trace subarachnoid hemorrhage. Two days after radiographic confirmation of an accurately placed EVD, she was found to have vertical gaze palsy (Parinaud’s syndrome). Repeat CT head demonstrated inward migration of the EVD with left midbrain compression. After readjustment of the EVD, her Parinaud’s syndrome improved each day until discharge home.

Conclusions: This is a novel clinical presentation of an EVD causing Parinaud’s syndrome. There is only one other case report in the literature of this phenomenon. Although a practical solution to prevent this incident from occurring is unclear, vigilance for changes in neurological exam allowed for quick assessment and revision of the EVD and subsequent recovery in this patient.

Development and Implementation of an Inexpensive, Easily Producible, Time Efficient External Ventricular Drain Simulator Using 3-Dimensional Printing and Image Registration

BACKGROUND

External ventricular drain (EVD) placement is one of the most commonly performed procedures in neurosurgery, frequently by the junior neurosurgery resident. Simulators for EVD placement are often costly, time-intensive to create, and complicated to set up.

OBJECTIVE

To describe creation of a simulator that is inexpensive, time-efficient, and simple to set up.

METHODS

This simulator involves printing a hollow head using a desktop 3-dimensional (3D) printer. This head is registered to a commercially available image-guidance system. A total of 11 participants volunteered for this simulation module. EVD placement was assessed at baseline, after verbal teaching, and after live 3D view instruction.

RESULTS

Accurate placement of an EVD on the right side at the foramen of Monro or the frontal horn of the lateral ventricle increased from 44% to 98% with training. Similarly, accurate placement on the left increased from 42% to 85% with training.

CONCLUSION

During participation in the simulation, accurate placement of EVDs increased significantly. All participants believed that they had a better understanding of ventricular anatomy and that this module would be useful as a teaching tool for neurosurgery interns.

Prefronto-thalamic tract injury and cognitive outcome according to external ventricular drainage location in stroke patients

OBJECTIVES

We investigated the characteristics of prefronto-thalamic tract (PF-TT) injuries in stroke patients using diffusion tensor tractography (DTT) and assessing cognitive outcome according to location of the external ventricular drainage (EVD).

METHODS

Forty-five consecutive stroke patients who underwent EVD and 24 control subjects were recruited. The patients were classified into three groups: group A (EVD on the lesion or one side, 17 patients), group B (EVD on the hemisphere opposite to the lesion, 12 patients), and group C (EVD on both sides, 16 patients). Mini-Mental State Examination (MMSE) results were performed at the beginning (average 2.27 months from onset) and end (average 4.19 months from onset) of rehabilitation. Three parts of the PF-TT (dorsolateral PF-TT[DLPF-TT], ventrolateral PF-TT[VLPF-TT], orbitofronto-thalamic tract[OF-TT]) were reconstructed and the fractional anisotropy (FA) and tract volume (TV) measurements were obtained.

RESULTS

With the EVD on the stroke-affected side, the values of FA and TV of all three parts of the PF-TTs in three patient groups were lower than those of the control group (p < 0.05). With the EVD on the unaffected side, the FA values of the DLPF-TT in groups B and C and the OF-TT in group C were lower than those of the control group (p < 0.05). There was no difference in initial MMSE score among three patient groups; however, group A had a higher mean follow-up MMSE score than that of groups B and C (p < 0.05).

CONCLUSIONS

Patients who underwent EVD of the affected hemisphere showed better results in terms of the PF-TT injury and cognitive outcome than patients who underwent EVD through the unaffected hemisphere or through both hemispheres.

The July Effect and its Impact on External Ventricular Drain Placement by Neurosurgical Trainees-Analysis of the National Inpatient Sample

OBJECTIVE

External ventricular drain (EVD) placement is a life-saving procedure performed frequently by neurosurgical residents. The July effect is a theoretic decline in quality of health care sometimes perceived in teaching hospitals at the start of an academic year. We sought to quantify the learning curve of ventriculostomy drain placement in teaching hospitals and determine its impact on patient outcomes, health care utilization, and cost.

METHODS

The National Inpatient Sample was queried for patients admitted nonelectively between 2012 and 2015 requiring EVD placement at a teaching hospital determined by using International Classification of Diseases, Ninth Revision codes. Rates of multiple EVD placements per admission, infection and hemorrhage, mortality, length and cost of hospital stay, and discharge disposition were compared between admissions in the first quarter (Q1) of an academic year (July-September) versus those in Q4 (April-June).

RESULTS

A total of 7783 admissions met inclusion criteria (3901 in Q1 and 3882 in Q4). The odds ratios (OR) for all combined complications, mortality, and long-term care disposition were similar between Q1 and Q4 groups. There was a significant reduction in the OR of wound and infectious complications in Q1 versus Q4 (1.60% vs. 2.31%; OR, 0.66; P = 0.01). The impact of Q1 EVD placement on total hospital charge and number of EVD codes was not statistically significant. However, there was a statistically significant reduction in length of stay in Q1 compared with Q4 (β = -0.04 days; P < 0.0001).

CONCLUSIONS

There was no evidence of a July effect on EVD complication rates in outcomes for patients admitted in the beginning of an academic year versus the end.

The Assessment of Geometric Reliability of Conventional Trajectory of Ventriculostomy in a Three Dimensional Virtual Model and Proposal of a New Trajectory

Ventriculostomy is a common neurosurgery procedure performed for many purposes. Kocher's point is most often used as the ventriculostomy entry point. But the accuracy of a cannula's trajectory into the ventricles from entry at Kocher's point is controversial. In this paper we attempt to evaluate the accuracy of the conventional sagittal trajectory, which uses Kocher's point, and evaluate a new trajectory by creating virtual ventriculostomy simulations from computed tomography images of the brain. About 66 patients without brain and skull pathology in radiography were included. Three dimensional images were constructed using thin sliced brain computed tomography images, and a virtual ventriculostomy was performed toward the previous used surface landmark. And the path of ideal ventricular catheter was simulated. The anterior surface landmarks included the ipsilateral medial canthus, the contralateral medial canthus, and the midpoint between bilateral medial canthi. The lateral surface landmark was the external auditory canal. The sagittal trajectory of the three surface landmarks located in the frontal horn of ipsilateral ventricle was 0% for the ipsilateral medial canthus, 87.88% for the midpoint between bilateral medial canthi and 26.52% for the contralateral medial canthus. The anterior surface target of ideal sagittal trajectory, which connects the Kocher's point with the central axis of ipsilateral ventricle, is contralaterally 6.7 mm away from midline. It was found that the conventional sagittal trajectory is inaccurate. The anterior target of surface landmark for the ideal sagittal trajectory is medial one third of the distance between the midline and the contralateral medial canthus.

Freehand Insertion of External Ventricular Drainage Catheter: Evaluation of Accuracy in a Single Center

Introduction

External ventricular drain (EVD) placement is the gold standard for managing acute hydrocephalus. Freehand EVD, using surface anatomical landmarks, is performed for ventricular cannulation due to its simplicity and efficiency. This study evaluates accuracy and reason(s) for misplacements as few studies have analyzed the accuracy of freehand EVD insertion.

Patients and Methods

Preoperative and postoperative computed tomography scans of patients who underwent EVD insertion in 2014 were retrospectively reviewed. Diagnosis, Evans ratio, midline shift, position of burr hole, length of the catheter, and procedural complications were tabulated. The procedures were classified as satisfactory (catheter tip in the frontal horn ipsilateral lateral ventricle) and unsatisfactory. Unsatisfactory cases were further analyzed in relation to position of burr hole from midline and length of the catheter.

Results

Seventy-seven EVD placements in seventy patients were evaluated. The mean age of the patients was 57.5 years. About 83.1% were satisfactory placements and 11.7% were unsatisfactory in the contralateral ventricle, corpus callosum, and interhemispheric fissure. Nearly 5.2% were in extraventricular locations. Almost 2.6% EVD placements were complicated by hemorrhage and 1 catheter was reinserted. Suboptimal placements were significantly associated with longer intracranial catheter length. The mean length was 66.54 ± 10.1 mm in unsatisfactory placements compared to 58.32 ± 4.85 mm in satisfactory placements. Between the two groups, no significant difference was observed in Evans ratio, midline shift, surgeon's experience, distance of burr hole from midline, and coronal suture.

Conclusion

Freehand EVD insertion is safe and accurate. In small number of cases, unsatisfactory placement is related to longer catheter length.

A wearable mixed-reality holographic computer for guiding external ventricular drain insertion at the bedside

OBJECTIVE

The goal of this study was to explore the feasibility and accuracy of using a wearable mixed-reality holographic computer to guide external ventricular drain (EVD) insertion and thus improve on the accuracy of the classic freehand insertion method for EVD insertion. The authors also sought to provide a clinically applicable workflow demonstration.

METHODS

Pre- and postoperative CT scanning were performed routinely by the authors for every patient who needed EVD insertion. Hologram-guided EVD placement was prospectively applied in 15 patients between August and November 2017. During surgical planning, model reconstruction and trajectory calculation for each patient were completed using preoperative CT. By wearing a Microsoft HoloLens, the neurosurgeon was able to visualize the preoperative CT-generated holograms of the surgical plan and perform EVD placement by keeping the catheter aligned with the holographic trajectory. Fifteen patients who had undergone classic freehand EVD insertion were retrospectively included as controls. The feasibility and accuracy of the hologram-guided technique were evaluated by comparing the time required, number of passes, and target deviation for hologram-guided EVD placement with those for classic freehand EVD insertion.

RESULTS

Surgical planning and hologram visualization were performed in all 15 cases in which EVD insertion involved holographic guidance. No adverse events related to the hologram-guided procedures were observed. The mean ± SD additional time before the surgical part of the procedure began was 40.20 ± 10.74 minutes. The average number of passes was 1.07 ± 0.258 in the holographic guidance group, compared with 2.33 ± 0.98 in the control group (p < 0.01). The mean target deviation was 4.34 ± 1.63 mm in the holographic guidance group and 11.26 ± 4.83 mm in the control group (p < 0.01).

CONCLUSIONS

This study demonstrates the use of a head-mounted mixed-reality holographic computer to successfully perform hologram-assisted bedside EVD insertion. A full set of clinically applicable workflow images is presented to show how medical imaging data can be used by the neurosurgeon to visualize patient-specific holograms that can intuitively guide hands-on operation. The authors also provide preliminary confirmation of the feasibility and accuracy of this hologram-guided EVD insertion technique.

The Evolution of the Role of External Ventricular Drainage in Traumatic Brain Injury

External ventricular drains (EVDs) are commonly used in neurosurgery in different conditions but frequently in the management of traumatic brain injury (TBI) to monitor and/or control intracranial pressure (ICP) by diverting cerebrospinal fluid (CSF). Their clinical effectiveness, when used as a therapeutic ICP-lowering procedure in contemporary practice, remains unclear. No consensus has been reached regarding the drainage strategy and optimal timing of insertion. We review the literature on EVDs in the setting of TBI, discussing its clinical indications, surgical technique, complications, clinical outcomes, and economic considerations.

Craniometrics and Ventricular Access: A Review of Kocher's, Kaufman's, Paine's, Menovksy's, Tubbs’, Keen's, Frazier's, Dandy's, and Sanchez's Points

Intraventricular access is frequently required during neurosurgery, and when neuronavigation is unavailable, the neurosurgeon must rely upon craniometrics to achieve successful ventricular cannulation. In this historical review, we summarize the most well-described ventricular access points: Kocher's, Kaufman's, Paine's, Menovksy's, Tubbs’, Keen's, Frazier's, Dandy's, and Sanchez's. Additionally, we provide multiview, 3-dimensional illustrations that provide the reader with a novel understanding of the craniometrics associated with each point.

The importance of aspirin, catheterization accuracy, and catheter design in external ventricular drainage-related hemorrhage: a multicenter study of 1002 procedures

BACKGROUND

External ventricular drainage (EVD) is the commonest neurosurgical procedure performed in daily neurosurgical practice, but relatively few studies have investigated the incidence and risk factors of its related hemorrhagic complications.

METHODS

This was a multicenter retrospective review of consecutive EVD procedures. Patients 18 years or older who underwent EVD and had a routine postoperative computed tomography (CT) scan performed within 24 hours were included. EVD-related hemorrhage was defined as new intracranial hemorrhage immediately adjacent or within the ventricular catheter trajectory. The volume of hemorrhage and the position of the catheter tip were assessed. A review of patient-, disease-, and surgery-related factors including the ventricular catheter design utilized was conducted. The Bonferroni correction was applied to the alpha level of significance (0.05) for multivariable analysis.

RESULTS

Nine hundred sixty-two patients underwent 1002 EVD performed by neurosurgeons in the operating theater. Sixteen percent (154) of patients were on aspirin before the procedure. Thirty-four percent (333) of patients had intracerebral hemorrhage, 25% (251) had aneurysmal subarachnoid hemorrhage and 16% (158) had traumatic brain injury. The mean duration from EVD to the first postoperative CT scan was 20 ± 4 h. EVD-related hematomas were detected after 81 procedures with a per-catheter risk of 8.1%. Mean hematoma volume was 1.2 ± 3.3 ml. Most were less than 1 ml (grade I, 79%, 64), 1 to 15 ml (grade II) in 20% (16) and a single clot larger than 15 ml (grade III, 1%) were detected. Clinically significant hemorrhage that resulted in catheter occlusion occurred in 1.7% (17) of procedures. Most catheters (62%, 625) were optimally placed, i.e., its tip being within the ipsilateral frontal horn or third ventricle. Three non-antibiotic-impregnated ventricular catheter designs were used with 55% (550) being the 2.2-mm Integra™ catheter, 14% (137) being the 2.8-mm Medtronic™ catheter, and 31% (315) being the 3.1-mm Codman™ catheter. Independent significant predictors for EVD-related hemorrhage were the preoperative prescription of aspirin (adjusted OR 1.94; 95% CI 1.10-3.44), catheter malposition (aOR 1.99; 95% CI 1.22-3.23), and use of the 2.8-mm Medtronic™ catheter (aOR 4.22; 95% CI 2.39-7.41).

CONCLUSIONS

The per-catheter risk of hemorrhage was 8.1%, but the incidence of symptomatic hemorrhage was low. The only patient risk factor was aspirin intake. This is the first study to evaluate and establish an association between catheter malposition and catheter design with EVD-related hemorrhage.

Utilizing preprocedural CT scans to identify patients at risk for suboptimal external ventricular drain placement with the freehand insertion technique

OBJECTIVE

Freehand insertion of external ventricular drains (EVDs) using anatomical landmarks is considered the primary method for placement, although alternative techniques have shown improved accuracy in positioning. The purpose of this study was to retrospectively evaluate which features of the baseline clinical history and preprocedural CT scan predict EVD positioning into suboptimal and unsatisfactory locations when using the freehand insertion technique.

METHODS

A retrospective chart review was performed evaluating 189 consecutive adult patients who received an EVD via freehand technique through an anterior burr hole between January 1, 2014, and December 31, 2015, at a Level 1 trauma facility in Edmonton, Alberta, Canada. The primary outcome measures included features associated with suboptimal positioning (Kakarla grade 1 vs Kakarla grades 2 and 3). The secondary outcome measures were features associated with unsatisfactory positioning (Kakarla grades 1 and 2 vs Kakarla grade 3).

RESULTS

Fifty-one EVDs (27%) were suboptimally positioned. Fifteen (8%) EVDs were placed into eloquent cortex or nontarget CSF spaces. Admitting diagnosis, head height-to-width ratio in axial plane, and side of predominant pathology were found to be significantly associated with suboptimal placement (p = 0.02, 0.012, and 0.02, respectively). A decreased height-to-width ratio was also associated with placement into only eloquent cortex and/or nontarget CSF spaces (p = 0.003).

CONCLUSIONS

Freehand insertion of an EVD is associated with significant suboptimal positioning into parenchyma and nontarget CSF spaces. The likelihood of inaccurate EVD placement can be predicted with baseline clinical and radiographic features. The patient's height-to-width ratio represents a novel potential radiographic predictor for malpositioning.

Image guidance and improved accuracy of external ventricular drain tip position particularly in patients with small ventricles

OBJECTIVE

External ventricular drain (EVD) insertion is one of the most common emergency neurosurgical procedures. EVDs are traditionally inserted freehand (FH) in an emergency setting, but often result in suboptimal positioning. Image-guided surgery (IGS) is selectively used to assist placement. However, the accuracy and practicality of IGS use is yet to be reported. In this study, the authors set out to assess if IGS is practical and improves the accuracy of EVD placement.

METHODS

Case notes and images obtained in patients who underwent frontal EVD placement were retrospectively reviewed. Ventriculomegaly was determined by the measurement of the Evans index. EVD location was classified as optimal (ipsilateral frontal horn) or suboptimal (any other location). Propensity score matching of the two groups (IGS vs FH) for the Evans index was performed. Data were analyzed for patient age, diagnosis, number of EVDs, and complications. Those without postoperative CT scans were excluded.

RESULTS

A total of 607 patients with 760 EVDs placed were identified; 331 met inclusion criteria. Of these, 287 were inserted FH, and 44 were placed with IGS; 60.6% of all unmatched FH EVDs were optimal compared with 75% of the IGS group (p = 0.067). The IGS group had a significantly smaller Evans index (p < 0.0001). Propensity score matching demonstrated improved optimal position in the IGS group when compared with the matched FH group (75% vs 43.2%, OR 4.6 [1.5-14.6]; p = 0.002). Patients with an Evans index of ≥ 0.36 derived less benefit (75% in IGS vs 66% in FH, p = 0.5), and those with an Evans index < 0.36 derived more benefit (75% in IGS vs 53% in FH, p = 0.024). The overall EVD complication rate was 36% in the FH group versus 18% in the IGS group (p = 0.056). Revision rates were higher in the FH group (p = 0.035), and the operative times were similar (p = 0.69). Long intracranial EVD catheters were associated with tip malposition irrespective of the group.

CONCLUSIONS

Image guidance is practical and improves the accuracy of EVD placement in patients with small ventricles; thus, it should be considered for these patients.

Safety, Accuracy, and Cost Effectiveness of Bedside Bolt External Ventricular Drains (EVDs) in Comparison with Tunneled EVDs Inserted in Theaters

OBJECTIVES

External ventricular drain (EVD) placement is required frequently in neurosurgical patients to divert cerebrospinal fluid and monitor intracranial pressure. The usual practice is the tunneled EVD technique performed in operating theaters. EVD insertion through a bolt in intensive care also is described. We employ both practices in our institute. Herein, we compare the indications, accuracy, safety, and costs of the 2 techniques.

METHODS

This was a retrospective cohort study of a prospectively maintained EVD database of all patients undergoing first frontal EVD placement between January 2010 and December 2015. Those patients with preceding cerebrospinal fluid infection were excluded. We compared bolt EVD with tunneled EVD techniques in terms of accuracy of EVD tip location by analyzing computed tomography scans to grade catheter tip location as optimal (ipsilateral frontal horn) or otherwise suboptimal, and complications that include infection and revision rates.

RESULTS

In total, 579 eligible patients aged 3 months to 84 years were identified; 430 had tunneled EVDs and 149 bolt EVDs. The most frequent diagnosis was intracranial hemorrhage (73% bolt vs. 50.4% tunneled group; P < 0.001). Other diagnoses included tumor (4.7% bolt vs. 19.1% tunneled; P < 0.001) and traumatic brain injury (17.5% bolt vs. 17.4% tunneled). In the bolt EVD group 66.4% of EVD tips were optimal, compared with 61.0% in the tunneled group (P = 0.33). Infection was confirmed in 15 (10.0%) bolt EVDs compared with 61 (14.2%) tunneled EVDs (P = 0.2). Each bolt EVD kit costs £260, whereas placing a tunneled one in the theater costs £1316.

CONCLUSIONS

Bedside bolt EVD placement is safe, accurate, and cost effective in selective patients with hemorrhage-related hydrocephalus.

Intraoperative Computed Tomography Versus Fluoroscopy for Ventriculoperitoneal Shunt Placement

OBJECTIVE

Catheter malposition represents one of the major causes of ventriculoperitoneal (VP) shunt dysfunction. The usefulness of intraoperative fluoroscopy using skull landmarks has already been proved to decrease catheter malposition and surgical revision rates. After introducing intraoperative computed tomography (iCT) in our department, our objective was to evaluate the accuracy of this imaging modality to decrease cranial catheter misplacement compared with intraoperative fluoroscopy.

METHODS

In our retrospective analysis of 152 patients, catheter placement was evaluated by iCT (n = 48) and biplane fluoroscopy (n = 57). A control group (n = 47) had no intraoperative imaging. Outcome measures included accuracy of ventricular catheter position, revision surgeries, and clinical outcomes.

RESULTS

Ventricular catheter placement was accurate in 24/48 patients with iCT and 45/57 patients with fluoroscopy (P = 0.002) versus 23/47 patients in the control group. Sensitivity and positive predictive value for estimating optimal catheter position with iCT were 100% and 54%. The specificity and negative predictive value were 50% and 100%. After intraoperative revision, 4 catheters remained malpositioned in the iCT group, whereas the fluoroscopy group had none (P = 0.03); 2 of these 4 catheters were revised postoperatively.

CONCLUSIONS

Fluoroscopy may be the method of choice to intraoperatively assess ventricular catheter positioning. In our experience, iCT shows a tendency to be more time consuming and, in the beginning, was not associated with a steeper learning curve. Another consideration was the significant higher radiation exposure per patient. iCT did not improve the accuracy of catheter placement and did not decrease early revisions for VP placement patients.

Factors Predicting Ventriculostomy Revision at a Large Academic Medical Center

BACKGROUND

Freehand bedside ventriculostomy placement can result in catheter malfunction requiring a revision procedure and cause significant patient morbidity. We performed a single-center retrospective review to assess factors related to this complication.

METHODS

Using an administrative database and chart review, we identified 101 first-time external ventricular drain placements performed at the bedside. We collected data regarding demographics, medical comorbidities, complications, and catheter tip location. We performed univariate and multivariate statistical analyses using MATLAB. We corrected for multiple comparisons using the false discovery rate (FDR) procedure.

RESULTS

Multivariate regression analyses revealed that revision procedures were more likely to occur after drain blockage (odds ratio [OR] 17.9) and hemorrhage (OR 10.3, FDR-corrected P values < 0.01, 0.05, respectively). Drain blockage was less frequent after placement in an "optimal location" (ipsilateral ventricle or near foramen of Monroe; OR 0.09, P = 0.009, FDR-corrected P < 0.03) but was more likely to occur after placement in third ventricle (post-hoc P values < 0.015). Primary diagnoses included subarachnoid hemorrhage (n = 30, 29.7%), intraparenchymal hemorrhage with intraventricular extravasation (n = 24, 23.7%), tumor (n = 20, 19.8%), and trauma (n = 17, 16.8%). Most common complications included drain blockage (n = 12, 11.8%) and hemorrhage (n = 8, 7.9%). In total, 16 patients underwent at least 1 revision procedure (15.8%).

CONCLUSIONS

Bedside external ventricular drain placement is associated with a 15% rate of revision, that typically occurred after drain blockage and postprocedure hemorrhage. Optimal placement within the ipsilateral frontal horn or foramen of Monroe was associated with a reduced rate of drain blockage.

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.