A survey of ventriculostomy and intracranial pressure monitor placement practices

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.

Construction and validation of infection risk model for patients with external ventricular drainage: a multicenter retrospective study

PURPOSE

External ventricular drainage (EVD) is a life-saving neurosurgical procedure, of which the most concerning complication is EVD-related infection (ERI). We aimed to construct and validate an ERI risk model and establish a monographic chart.

METHODS

We retrospectively analyzed the adult EVD patients in four medical centers and split the data into a training and a validation set. We selected features via single-factor logistic regression and trained the ERI risk model using multi-factor logistic regression. We further evaluated the model discrimination, calibration, and clinical usefulness, with internal and external validation to assess the reproducibility and generalizability. We finally visualized the model as a nomogram and created an online calculator (dynamic nomogram).

RESULTS

Our research enrolled 439 EVD patients and found 75 cases (17.1%) had ERI. Diabetes, drainage duration, site leakage, and other infections were independent risk factors that we used to fit the ERI risk model. The area under the receiver operating characteristic curve (AUC) and the Brier score of the model were 0.758 and 0.118, and these indicators' values were similar when internally validated. In external validation, the model discrimination had a moderate decline, of which the AUC was 0.720. However, the Brier score was 0.114, suggesting no degradation in overall performance. Spiegelhalter's Z-test indicated that the model had adequate calibration when validated internally or externally (P = 0.464 vs. P = 0.612). The model was transformed into a nomogram with an online calculator built, which is available through the website: https://wang-cdutcm.shinyapps.io/DynNomapp/ .

CONCLUSIONS

The present study developed an infection risk model for EVD patients, which is freely accessible and may serve as a simple decision tool in the clinic.

Augmented Reality-Assisted versus Freehand Ventriculostomy in a Head Model

BACKGROUND

 Ventriculostomy (VST) is a frequent neurosurgical procedure. Freehand catheter placement represents the standard current practice. However, multiple attempts are often required. We present augmented reality (AR) headset guided VST with in-house developed head models. We conducted a proof of concept study in which we tested AR-guided as well as freehand VST. Repeated AR punctures were conducted to investigate if a learning curve can be derived.

METHODS

 Five custom-made 3D-printed head models, each holding an anatomically different ventricular system, were filled with agarose gel. Eleven surgeons placed two AR-guided as well as two freehand ventricular drains per head. A subgroup of four surgeons did a total of three series of AR-guided punctures each to test for a learning curve. A Microsoft HoloLens served as the hardware platform. The marker-based tracking did not require rigid head fixation. Catheter tip position was evaluated in computed tomography scans.

RESULTS

 Marker-tracking, image segmentation, and holographic display worked satisfactorily. In freehand VST, a success rate of 72.7% was achieved, which was higher than under AR guidance (68.2%, difference not statistically significant). Repeated AR-guided punctures increased the success rate from 65 to 95%. We assume a steep learning curve as repeated AR-guided punctures led to an increase in successful attempts. Overall user experience showed positive feedback.

CONCLUSIONS

 We achieved promising results that encourage the continued development and technical improvement. However, several more developmental steps have to be taken before an application in humans can be considered. In the future, AR headset-based holograms have the potential to serve as a compact navigational help inside and outside the operating room.

Risk Factors for External Ventricular Drainage-Related Infection: A Systematic Review and Meta-analysis

Background and Objectives

External ventricular drainage (EVD) is one of the most commonly performed neurosurgical procedures, but EVD-related infection constitutes a significant health concern. Yet, little consensus identifies the risk factors for the development of EVD-related infection. Therefore, we performed a meta-analysis to systematically summarize existing evidence on the incidence and risk factors for EVD-related infection.

Methods

PubMed, Embase, and the Cochrane Library databases from database inception to February 28, 2022, were searched for all studies investigating the incidence and risk factors for EVD-related infection. Data were assessed by R-4.2.0 software. The meta-analysis was used to calculate pooled odds ratios (OR) and 95% confidence intervals (CI).

Results

A total of 48 studies were included. Among the 29 factors analyzed, statistically significant risk factors were subarachnoid hemorrhage(SAH)/intraventricular hemorrhage(IVH) (OR = 1.48, 95% CI = 1.20-1.82, p < 0.001), concomitant systemic infection (OR = 1.90, 95% CI = 1.34-2.70, p < 0.001), other neurosurgical procedures (OR = 1.76, 95% CI = 1.02-3.04, p = 0.041), change of catheter (OR = 5.05, 95% CI = 3.67-6.96, p < 0.001), bilateral EVDs (OR = 2.25, 95% CI = 1.03-4.89, p = 0.041), (cerebrospinal fluid) CSF leak (OR = 3.19, 95% CI = 2.12-4.81, p < 0.001) and duration of EVD >7 days (OR = 4.62, 95% CI = 2.26-9.43, p < 0.001). The use of silver-coated catheters (OR = 0.57, 95% CI = 0.38-0.87, p = 0.008) and antibiotic-impregnated catheters (OR = 0.60, 95% CI = 0.41-0.88, p = 0.009) might help reduce the risk of infection. No significant difference was indicated in studies evaluating factors like diabetes mellitus (OR = 1.25, 95% CI = 0.90-1.75, p = 0.178), steroids used (OR = 1.52, 95% CI = 0.96-2.4, p = 0.074), prophylactic antibiotics(OR = 0.87, 95% CI = 0.66-1.14, p = 0.308).

Discussion

The meta-analysis of various relevant factors in the onset of EVD-related infection in patients submitted to EVD enabled us to establish a more probable profile of the patients who are more likely to develop it during the treatment.

Multimodal Haptic Simulation for Ventriculostomy Training. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023;2023:1-4. [PMID: 38083370 DOI: 10.1109/embc40787.2023.10340701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Freehand ventriculostomy is a frequent surgical procedure and is among the first ones that junior neurosurgery residents learn. Although training simulators exist, none has been adopted in the clinical routine to train junior residents. This paper focuses on a novel multimodal haptic training simulator that will lift the limitations of current simulators. We thus propose an architecture that integrates (1) visual feedback through augmented MRIs, and (2) a physical mock-up of the patient's skull to (3) active haptic feedback.

The Use of Intraventricular Instillation of Vancomycin to Prevent External Ventricular Drainage Related Infection: A Clinical Prospective Study

BACKGROUND

External ventricular drainage (EVD)-related infection (ERI) represents an important condition with potential high morbidity with significant impact on patient outcomes. Prophylactic systemic antibiotics are routinely administered to patients with EVD, but they do not significantly lower the incidence of ERIs. Intraventricular treatment with vancomycin appeared to be safe and effective, but most reports are case-reports/-series and retrospective studies.

METHODS

A prospective non-randomized case-control study was conducted in a consecutive series of 116 patients treated with EVD insertion. The study includes the group of patients treated with intrathecal vancomycin (Group A, 62 patients) compared with the control group treated with daily intravenous cefazolin (Group B, 54 patients).

RESULTS

No statistically significant differences were found between the 2 groups with regard to the duration of catheterization and occurrence of ERI during hospitalization. EVD was replaced in 16 cases (25.8%) in group A and in 12 cases (22.2%) in the control group B (P 0.67). Three cases (4.8%) of ERI have been found in group A and 5 (9.3%) in the control group (P = 0.34). All reported cases of infection in group A were caused by gram-negative agents; on the opposite, cases of infections in the control group B were caused above all by gram-positive bacteria with a statistical difference (P = 0.03).

CONCLUSIONS

In this first prospective study on this topic, we found that intrathecal Vancomycin administration in EVDs does not reduce the occurrence of ERI compared with intravenous cefazolin prophylaxis, but induces selection of gram-negative bacteria.

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.

A Morphometric Analysis of Commonly Used Craniometric Approaches for Freehand Ventriculoperitoneal Shunting

BACKGROUND

Ventricular catheter tip position is a predictor for ventriculoperitoneal shunt survival. Cannulation is often performed freehand, but there is limited consensus on the best craniometric approach.

OBJECTIVE

To determine the accuracy of localizing craniometric entry sites and to identify which is associated with optimal catheter placement.

METHODS

This is a retrospective analysis of adult patients who underwent ventriculoperitoneal shunting. The approaches were categorized as Kocher's, Keen's, Frazier's and Dandy's points as well as the parieto-occipital point. An accurately sited burr hole was within 10 mm from standard descriptions. Optimal catheter tip position was defined as within the ipsilateral frontal horn.

RESULTS

A total of 110 patients were reviewed, and 58% (65/110) of burr holes were accurately sited. Keen's point was the most correctly identified (65%, 11/17), followed by Kocher's point (65%, 37/57) and Frazier's point (60%, 3/5). Predictors for accurate localization were Keen's point (odds ratio 0.3; 95% CI: 01-0.9) and right-sided access (odds ratio 0.4; 95% CI: 0.1-0.9). Sixty-three percent (69/110) of catheters were optimally placed with Keen's point (adjusted odds ratio 0.04; 95% CI: 0.01-0.67), being the only independent factor. Thirteen patients (12%) required shunt revision at a mean duration of 10 ± 25 mo. Suboptimal catheter tip position was the only independent determinant for revision (adjusted odds ratio 0.11; 95% CI: 0.01-0.98).

CONCLUSION

This is the first study to compare the accuracy of freehand ventricular cannulation of standard craniometric entry sites for adult patients. Keen's point was the most accurately sited and was a predictor for optimal catheter position. Catheter tip location, not the entry site, predicted shunt survival.

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.

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.

Development and validation of a rapidly deployable CT-guided stereotactic system for external ventricular drainage: preclinical study

External ventricular drainage (EVD) is an emergency neurosurgical procedure to decrease intracranial pressure through a catheter mediated drainage of cerebrospinal fluid. Most EVD catheters are placed using free hands without direct visualization of the target and catheter trajectory, leading to a high rate of complications- hemorrhage, brain injury and suboptimal catheter placement. Use of stereotactic systems can prevent these complications. However, they have found limited application for this procedure due to their long set-up time and expensive hardware. Therefore, we have developed and pre-clinically validated a novel 3D printed stereotactic system for rapid and accurate implantation of EVD catheters. Its mechanical and imaging accuracies were found to be at par with clinical stereotactic systems. Preclinical trial in human cadaver specimens revealed improved targeting accuracy achieved within an acceptable time frame compared to the free hand technique. CT angiography emulated using cadaver specimen with radio-opaque vascular contrast showed vessel free catheter trajectory. This could potentially translate to reduced hemorrhage rate. Thus, our 3D printed stereotactic system offers the potential to improve the accuracy and safety of EVD catheter placement for patients without significantly increasing the procedure time.

Role of Ultrasound in Neurocritical Care

Bedside point of care ultrasound has acquired an extremely significant role in diagnosis and management of neurocritical care, just as it has in other specialties. Easy availability and increasing expertise have allowed the intensivists to use it in a wide array of situations, such as confirming clinical findings as well as for interventional and prognostic purposes. At present, the clinical applications of ultrasonography (USG) in a neurosurgical patient include estimation of elevated intracranial pressure (ICP), assessment of cerebral blood flow (CBF) and velocities, diagnosis of intracranial mass lesion and midline shifts, and examination of pupils, apart from the systemic applications. Transcranial sonography has also found use in the diagnosis of the cerebral circulatory arrest. An increasing number of clinicians are now relying on the use of ultrasound in the neurointensive care unit for neurological as well as non-neurological indications. These uses include the diagnosis of shock, respiratory failure, deep vein thrombosis and performing bedside procedures.

Predictors of ventriculostomy infection in a large single-center cohort

OBJECTIVE

External ventricular drain (EVD) placement is a common neurosurgical procedure. While this procedure is simple and effective, infection is a major limiting factor. Factors predictive of infection reported in the literature are not conclusive. The aim of this retrospective, single-center large series was to assess the rate and independent predictors of ventriculostomy-associated infection (VAI).

METHODS

The authors performed a retrospective chart review of consecutive patients who underwent EVD placement between January 2012 and January 2018.

RESULTS

A total of 389 patients were included in the study. The infection rate was 3.1% (n = 12). Variables that were significantly associated with VAI were EVD replacement (OR 10, p = 0.001), bilateral EVDs (OR 9.2, p = 0.009), duration of EVD placement (OR 1.1, p = 0.011), increased CSF output/day (OR 1.0, p = 0.001), CSF leak (OR 12.9, p = 0.001), and increased length of hospital stay (OR 1.1, p = 0.002). Using multivariate logistic regression, independent predictors of VAI were female sex (OR 7.1, 95% CI 1.1–47.4; p = 0.043), EVD replacement (OR 8.5, 95% CI 1.44–50.72; p = 0.027), increased CSF output/day (OR 1.01, 95% CI 1.0–1.02; p = 0.023), and CSF leak (OR 15.1, 95% CI 2.6–87.1; p = 0.003).

CONCLUSIONS

The rate of VAI was 3.1%. Routine CSF collection (every other day or every 3 days) and CSF collection when needed were not associated with VAI. The authors recommend CSF collection when clinically needed rather than routinely.

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.

Beyond guidelines: analysis of current practice patterns of AANS/CNS tumor neurosurgeons

INTRODUCTION

Evidence-based medicine guidelines are increasingly published and sanctioned by organized neurosurgery. However, implementation, interpretation, and use of clinical guidelines may vary substantially on a regional, national and international basis. Survey research can help bridge the gap by providing a snapshot of neurosurgeon attitudes, knowledge, and practices. The American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS) Section on Tumors formed a Survey Committee to formalize the process by which surveys are submitted and reviewed before distribution to our membership. The goal of this committee is to provide peer-review so that collected information will be scientifically robust and useful to the neurosurgical community.

METHODS

Surveys submitted to the AANS/CNS tumor section between 2015 and 2019 were reviewed and metrics such as response rate and publication status assessed.

RESULTS

Six surveys were submitted to the Survey Committee of the AANS/CNS section on tumors between 2015 and 2019. Four have been circulated to section members, of which three have been published. Response rate has averaged 19% (range 16-23%), a majority of respondents (mean 70%) practice in academic settings.

CONCLUSIONS

The AANS/CNS Section on Tumors Survey Committee has and continues to help promote and improve the practice of surveying our community to answer important questions that can advance future training, research, and practice. There remains significant room for improvement in response rates, but ongoing tumor section efforts to increase member engagement will likely improve these numbers.

Augmented reality-assisted ventriculostomy

OBJECTIVE

Placement of a ventricular drain is one of the most common neurosurgical procedures. However, a higher rate of successful placements with this freehand procedure is desirable. The authors' objective was to develop a compact navigational augmented reality (AR)-based tool that does not require rigid patient head fixation, to support the surgeon during the operation.

METHODS

Segmentation and tracking algorithms were developed. A commercially available Microsoft HoloLens AR headset in conjunction with Vuforia marker-based tracking was used to provide guidance for ventriculostomy in a custom-made 3D-printed head model. Eleven surgeons conducted a series of tests to place a total of 110 external ventricular drains under holographic guidance. The HoloLens was the sole active component; no rigid head fixation was necessary. CT was used to obtain puncture results and quantify success rates as well as precision of the suggested setup.

RESULTS

In the proposed setup, the system worked reliably and performed well. The reported application showed an overall ventriculostomy success rate of 68.2%. The offset from the reference trajectory as displayed in the hologram was 5.2 ± 2.6 mm (mean ± standard deviation). A subgroup conducted a second series of punctures in which results and precision improved significantly. For most participants it was their first encounter with AR headset technology and the overall feedback was positive.

CONCLUSIONS

To the authors' knowledge, this is the first report on marker-based, AR-guided ventriculostomy. The results from this first application are encouraging. The authors would expect good acceptance of this compact navigation device in a supposed clinical implementation and assume a steep learning curve in the application of this technique. To achieve this translation, further development of the marker system and implementation of the new hardware generation are planned. Further testing to address visuospatial issues is needed prior to application in humans.

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.

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.

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.

A Method for Monitoring the Working States of Drainage Tubes Based on the Principle of Capacitance Sensing

The real-time monitoring of the working status of drainage tubes is crucial for successful surgical drainage and for informing clinicians of the drainage conditions of patients at different stages, to enable objective diagnosis and treatment. In this study, a method for monitoring the drainage condition of drainage tubes was proposed. The method was based on the principle of capacitance and was developed by analyzing the major states of drainage tubes in the process of drainage. Meanwhile, the principle of interdigital capacitance monitoring drainage was analyzed, and an interdigital capacitance device for the real-time monitoring of the working status of drainage tubes was designed. Ultimately, an experimental system for drainage simulation was established on the basis of the interdigital capacitance device and method for drainage monitoring. Results showed that the interdigital capacitance device for drainage monitoring can identify unobstructed or blocked drainage tubes effectively in real time. The device has a hydrophobic surface, so its electrodes do not undergo electrolysis and pollution due to adhesion. Hence the proposed capacitance-based method for monitoring the working states of drainage tubes has good application prospects in the postoperative drainage of abdominal and thoracic cavities.

External Ventricular Drain Placement Accuracy and Safety When Done by Midlevel Practitioners

BACKGROUND

External ventricular drains (EVDs) measure intracranial pressure, divert cerebrospinal fluid, and allow for orthotropic administration of pharmacologic agents. Currently, neurosurgeons and neurosurgery residents are the primary practitioners placing EVDs. Due to the urgency of neurosurgical pathologies and the lack of qualified residents at most hospitals, midlevel practitioner (MLP) placement of EVDs would be advantageous.

OBJECTIVE

To assess the accuracy and complication rates of MLP and neurosurgeon EVD placement.

METHODS

This was a retrospective cohort of all patients with an EVD placed between January 2012 and September 2016 at a level 1 trauma center. We compared safety and accuracy of EVD placement between neurosurgeons and MLPs.

RESULTS

MLP first attempted EVD placement in 238 patients and senior neurosurgeon first attempted EVD placement in 70 subjects. There was no significant difference between accuracy of placement within the ventricle (87.4% vs 90.0%, P = .5557), hemorrhage rate (5.9% vs 4.3%, P = .77), or infection rate (0.8% vs 1.4%, P = .5399) for placement attempted by an MLP compared with a neurosurgeon, respectively.

CONCLUSION

MLPs perform EVD placement safely with no significant difference in accuracy of placement or complication rates compared with placement by senior neurosurgeons. This may allow for earlier management of elevated intracranial pressure and access to care where previously unavailable; leading to improved patient outcomes.

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.

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.

The Aalborg Bolt-Connected Drain (ABCD) study: a prospective comparison of tunnelled and bolt-connected external ventricular drains

BACKGROUND

Acutely increased intracranial pressure (ICP) is frequently managed by external ventricular drainage (EVD). This procedure is life-saving but marred by a high incidence of complications. It has recently been indicated that bolt-connected external ventricular drainage (BC-EVD) compared to the standard technique of tunnelled EVD (T-EVD) may result in less complications.

AIM

To prospectively sample and compare two cohorts by consecutive allocation to either BC-EVD or T-EVD from the introduction of the BC-EVD technique in our department and 12 months onward.

METHODS

Patients undergoing ventriculostomy between the 1st of March 2017 and the 28th of February 2018 were considered for inclusion. The neurosurgeon on-call sovereignly set the indication and decided on EVD type (BC-EVD or T-EVD), consequently resulting in two cohorts as 3/7 senior neurosurgeons on call were open to the use of BC-EVD, while 4/7 were reluctant to use this technique. Data was continuously collected using patient records, including results of cerebrospinal fluid (CSF) culturing and available CT/MRI-scans. Recorded complications included CSF leakage, accidental discontinuation, placement-related intracranial haemorrhage, malfunction, migration, infection and revision.

RESULTS

Forty-nine EVDs (32 T-EVDs/17 BC-EVDs) were included; 19/32 (59.4%) T-EVDs and 3/17 (17.6%) BC-EVDs were found to have complications (p = 0.007). The relative risk of complications when using T-EVD was 3.4 times that of BC-EVD.

CONCLUSION

Ventriculostomy by BC-EVD compared to T-EVD reduces incidence and risk of complications and should be the first choice in EVD placement. That said, T-EVD has a role in paediatric patients and for intraoperatively and occipitally placed EVDs.

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.

Management of External Ventricular Drains After Subarachnoid Hemorrhage: A Multi-Institutional Survey

BACKGROUND

Patients with aneurysmal subarachnoid hemorrhage (SAH) often develop hydrocephalus requiring an external ventricular drain (EVD). The best available evidence suggests that a rapid EVD wean and intermittent CSF drainage is safe, reduces complications, and shortens ICU and hospital length of stay as compared to a gradual wean and continuous drainage. However, optimal EVD management remains controversial and the baseline practice among neurological ICUs is unclear. Therefore, we sought to determine current institutional practices of EVD management for patients with aneurysmal SAH.

METHODS

An e-mail survey was sent to attending intensivists and neurosurgeons from 72 neurocritical care units that are registered with the Neurocritical Care Research Network or have been previously associated with the existing literature on the management of EVDs in critically ill patients. Only one response was counted per institution.

RESULTS

There were 45 out of 72 institutional responses (63%). The majority of responding institutions (80%) had a single predominant EVD management approach. Of these, 78% favored a gradual EVD weaning strategy. For unsecured aneurysms, 81% kept the EVD continuously open and 19% used intermittent drainage. For secured aneurysms, 94% kept the EVD continuously open and 6% used intermittent drainage. Among continuously drained patients, the EVD was leveled at 18 (unsecured) and 11 cm H₂O (secured) (p < 0.0001). When accounting for whether the EVD strategy was to enhance or minimize CSF drainage, there was a significant difference in the management of unsecured versus secured aneurysms with 42% using an enhance drainage approach in unsecured patients and 92% using an enhance drainage approach in secured patients (p < 0.0001).

CONCLUSION

Most institutions utilize a single predominant EVD management approach, with a consensus toward a continuously open EVD to enhance CSF drainage in secured aneurysm patients coupled with a gradual weaning strategy. This finding is surprising given that the best available evidence suggests that the opposite approach is safe and can reduce ICU and hospital length of stay. We recommend a critical reassessment of the approach to the management of EVDs. Given the potential impact on patient outcomes and length of stay, more research needs to be done to reach a threshold for practice change, ideally via multicenter and randomized trials.

An Evaluation of Commonly Used External Ventricular Drain Securement Methods in a Porcine Model: Recommendations to Improve Practice

BACKGROUND

External ventricular drain (EVD) dislodgement is common and leads to significant morbidity and mortality. Many securement techniques to prevent this are described. There are, however, no objective studies comparing them. This study aimed to determine the most secure method of securing an EVD.

METHODS

A survey was distributed through the British Neurosurgical Trainee Research Collaborative to determine common EVD securement methods and select techniques for testing. Securement methods were tested in a pig cadaver model. Peak pull force before EVD failure was measured. Failure was defined as catheter displacement 1 cm from the insertion site, catheter fracture, or suture fracture.

RESULTS

Twenty-three neurosurgical units responded. Five basic EVD securement methods were in common use. These were tested in isolation and in combination so that in total 15 common methods were tested. The most secure method was a triple construct, consisting of an anchoring suture, sutures around a coil of the catheter, and either a soft plastic flange (25.85 N, 95% confidence interval 24.95 N-26.75 N) or a hard plastic flange (29.05 N, 95% confidence interval 25.69 N-32.41 N). Of the individual methods, single anchoring sutures, soft flanges, VentriFix, and staples were found to be the least secure, whereas multiple sutures and hard flanges were the most secure.

CONCLUSIONS

An anchoring suture followed by a coil of the catheter and finally a flange is the most secure method for securing EVDs. This simple technique can withstand up to 8.2 times the force of a single anchoring suture, is easily used, and decreases the likelihood of EVD dislodgement and associated complications.

Cost Effectiveness of Intracranial Pressure Monitoring in Pediatric Patients with Severe Traumatic Brain Injury: A Simulation Modeling Approach

OBJECTIVES

To conduct an economic evaluation of intracranial pressure (ICP) monitoring on the basis of current evidence from pediatric patients with severe traumatic brain injury, through a statistical model.

METHODS

The statistical model is a decision tree, whose branches take into account the severity of the lesion, the hospitalization costs, and the quality-adjusted life-year for the first 6 months post-trauma. The inputs consist of probability distributions calculated from a sample of 33 surviving children with severe traumatic brain injury, divided into two groups: with ICP monitoring (monitoring group) and without ICP monitoring (control group). The uncertainty of the parameters from the sample was quantified through a probabilistic sensitivity analysis using the Monte-Carlo simulation method. The model overcomes the drawbacks of small sample sizes, unequal groups, and the ethical difficulty in randomly assigning patients to a control group (without monitoring).

RESULTS

The incremental cost in the monitoring group was Mex$3,934 (Mexican pesos), with an increase in quality-adjusted life-year of 0.05. The incremental cost-effectiveness ratio was Mex$81,062. The cost-effectiveness acceptability curve had a maximum at 54% of the cost effective iterations. The incremental net health benefit for a willingness to pay equal to 1 time the per capita gross domestic product for Mexico was 0.03, and the incremental net monetary benefit was Mex$5,358.

CONCLUSIONS

The results of the model suggest that ICP monitoring is cost effective because there was a monetary gain in terms of the incremental net monetary benefit.

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.

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.

An analysis of neurosurgical practice patterns and outcomes for serious to critical traumatic brain injuries in a mature trauma state

BACKGROUND

We sought to characterize trends in neurosurgical practice patterns and outcomes for serious to critical traumatic brain injuries from 2003 to 2013 in the mature trauma state of Pennsylvania.

METHODS

All 2003 to 2013 admissions to Pennsylvania's 30 accredited Level I to II trauma centers with serious to critical traumatic brain injuries (head Abbreviated Injury Scale [AIS] score ≥ 3, Glasgow Coma Scale [GCS] score < 13) were extracted from the state registry. Adjusted temporal trend tests controlling for demographic and injury severity covariates assessed the impact of admission year on intervention rates (craniotomy, craniectomy, and intracranial pressure monitor/ventriculostomy [ICP]) and outcome measures for the total population as well as serious (head AIS score ≥ 3; GCS score, 9-12) and critical (head AIS score ≥ 3, GCS score ≤ 8) subgroups.

RESULTS

A total of 22,229 patients met inclusion criteria. Admission year was significantly associated with an adjusted increase in craniectomy (adjusted odds ratio [AOR], 1.12 [1.09-1.14]; p < 0.001) and ICP rates (AOR, 1.03 [1.02-1.04]; p < 0.001) and a decrease in craniotomy rate (AOR, 0.96 [0.95-0.97]; p < 0.001). No significant trends in adjusted mortality were found for the total study population (AOR, 1.01 [1.00-1.02]; p = 0.150); however, a significant reduction was found for the serious subgroup (AOR, 0.95 [0.92-0.98]; p = 0.002), and a significant increase was found for the critical subgroup (AOR, 1.02 [1.01-1.03]; p = 0.004).

CONCLUSION

Total study population trends showed a reduction in rates of craniotomy and increase in craniectomy and ICP rates without any change in outcome. Despite significant adaptations in neurosurgical practice patterns from 2003 to 2013, only patients with serious head injuries are experiencing improved survival.

LEVEL OF EVIDENCE

Prognostic and epidemiologic study, level III; therapeutic study, level IV.

Device for Catheter Placement of External Ventricular Drain

To introduce a new device for catheter placement of an external ventricular drain (EVD) of cerebrospinal fluid (CSF). This device was composed of three portions, T-shaped main body, rectangular pillar having a central hole to insert a catheter and an arm pointing the tragus. The main body has a role to direct a ventricular catheter toward the right or left inner canthus and has a shallow longitudinal opening to connect the rectangular pillar. The arm pointing the tragus is controlled by back and forth movement and turn of the pillar attached to the main body. Between April 2012 and December 2014, 57 emergency EVDs were performed in 52 patients using this device in the operating room. Catheter tip located in the frontal horn in 52 (91.2%), 3rd ventricle in 2 (3.5%) and in the wall of the frontal horn of the lateral ventricle in 3 EVDs (5.2%). Small hemorrhage along to catheter tract occurred in 1 EVD. CSF was well drained through the all EVD catheters. The accuracy of the catheter position and direction using this device were 91% and 100%, respectively. This device for EVD guides to provide an accurate position of catheter tip safely and easily.

Design Optimization of a Magnetic Field-Based Localization Device for Enhanced Ventriculostomy

The accuracy of many freehand medical procedures can be improved with assistance from real-time localization. Magnetic localization systems based on harnessing passive permanent magnets (PMs) are of great interest to track objects inside the body because they do not require a powered source and provide noncontact sensing without the need for line-of-sight. While the effect of the number of sensors on the localization accuracy in such systems has been reported, the spatial design of the sensing assembly is an open problem. This paper presents a systematic approach to determine an optimal spatial sensor configuration for localizing a PM during a medical procedure. Two alternative approaches were explored and compared through numerical simulations and experimental investigation: one based on traditional grid configuration and the other derived using genetic algorithms (GAs). Our results strongly suggest that optimizing the spatial arrangement has a larger influence on localization performance than increasing the number of sensors in the assembly. We found that among all the optimization schemes, the approach utilizing GA produced sensor designs with the smallest localization errors.

Intracranial Pressure Monitoring as a Part of Multimodal Monitoring Management of Patients with Critical Polytrauma: Correlation between Optimised Intensive Therapy According to Intracranial Pressure Parameters and Clinical Picture

OBJECTIVE

Trauma patient requires a complex therapeutic management because of multiple severe injuries or secondary complications. The most significant injury found in patients with trauma is head injury, which has the greatest impact on mortality. Intracranial pressure (ICP) monitoring is required in severe traumatic head injury because it optimises treatment based on ICP values and cerebral perfusion pressure (CPP).

METHODS

From a total of 64 patients admitted in the intensive care unit (ICU) 'Casa Austria', from the Polytraumatology Clinic of the Emergency County Hospital "Pius Brinzeu" Timisoara, Romania, between January 2014 and December 2014; only patients who underwent ICP monitoring (n=10) were analysed. The study population was divided into several categories depending on the time passed since trauma to the time of installation of ICP monitoring (<18 h, 19-24 h and >24 h). Comparisons were made in terms of the number of days admitted in the ICU and mortality between patients with head injury who benefited and those who did not benefit from ICP monitoring.

RESULTS

The results show the positive influence of ICP monitoring on the number of admission days in ICU because of the possibility that the number of admission days to augment therapeutic effects in patients who benefited from ICP monitoring reduces by 1.93 days compared with those who did not undergo ICP monitoring.

CONCLUSION

ICP monitoring and optimizing therapy according to the ICP and CPP has significant influence on the rate of survival. ICP monitoring is necessary in all patients with head trauma injury according to recent guidelines. The main therapeutic goal in the management of the trauma patient with head injury is to minimize the destructive effects of the associated side effects.

Ultrasound stylet for non-image-guided ventricular catheterization

OBJECT Urgent ventriculostomy placement can be a lifesaving procedure in the setting of hydrocephalus or elevated intracranial pressure. While external ventricular drain (EVD) insertion is common, there remains a high rate of suboptimal drain placement. Here, the authors seek to demonstrate the feasibility of an ultrasound-based guidance system that can be inserted into an existing EVD catheter to provide a linear ultrasound trace that guides the user toward the ventricle. METHODS The ultrasound stylet was constructed as a thin metal tube, with dimensions equivalent to standard catheter stylets, bearing a single-element, ceramic ultrasound transducer at the tip. Ultrasound backscatter signals from the porcine ventricle were processed by custom electronics to offer real-time information about ventricular location relative to the catheter. Data collected from the prototype device were compared with reference measurements obtained using standard clinical ultrasound imaging. RESULTS A study of porcine ventricular catheterization using the experimental device yielded a high rate of successful catheter placement after a single pass (10 of 12 trials), despite the small size of pig ventricles and the lack of prior instruction on porcine ventricular architecture. A characteristic double-peak signal was identified, which originated from ultrasound reflections off of the near and far ventricular walls. Ventricular dimensions, as obtained from the width between peaks, were in agreement with standard ultrasound reference measurements (p < 0.05). Furthermore, linear ultrasound backscatter data permitted in situ measurement of the stylet distance to the ventricular wall (p < 0.05), which assisted in catheter guidance. CONCLUSIONS The authors have demonstrated the ability of the prototype ultrasound stylet to guide ventricular access in the porcine brain. The alternative design of the device makes it potentially easy to integrate into the standard workflow for bedside EVD placement. The availability of a fast, easy-to-use, inexpensive guidance system can play a role in reducing the complication rate for EVD placement.