Non-assisted versus neuro-navigated and XperCT-guided external ventricular catheter placement: a comparative cadaver study

Background and purpose: Accurate placement of an external ventricular drain (EVD) for the treatment of hydrocephalus is of paramount importance for its functionality and in order to minimize morbidity and complications. The aim of this study was to compare two different drain insertion assistance tools with the traditional free-hand anatomical landmark method, and to measure efficacy, safety and precision. Methods: Ten cadaver heads were prepared by opening large bone windows centered on Kocher's points on both sides. Nineteen physicians, divided in two groups (trainees and board certified neurosurgeons) performed EVD insertions. The target for the ventricular drain tip was the ipsilateral foramen of Monro. Each participant inserted the external ventricular catheter in three different ways: 1) free-hand by anatomical landmarks, 2) neuronavigation-assisted (NN), and 3) XperCT-guided (XCT). The number of ventricular hits and dangerous trajectories; time to proceed; radiation exposure of patients and physicians; distance of the catheter tip to target and size of deviations projected in the orthogonal plans were measured and compared. Results: Insertion using XCT increased the probability of ventricular puncture from 69.2 to 90.2% (p = 0.02). Non-assisted placements were significantly less precise (catheter tip to target distance 14.3 ± 7.4mm versus 9.6 ± 7.2mm, p = 0.0003). The insertion time to proceed increased from 3.04 ± 2.06min. to 7.3 ± 3.6min. (p < 0.001). The X-ray exposure for XCT was 32.23mSv, but could be reduced to 13.9mSv if patients were initially imaged in the hybrid-operating suite. No supplementary radiation exposure is needed for NN if patients are imaged according to a navigation protocol initially. Conclusion: This ex vivo study demonstrates a significantly improved accuracy and safety using either NN or XCT-assisted methods. Therefore, efforts should be undertaken to implement these new technologies into daily clinical practice. However, the accuracy versus urgency of an EVD placement has to be balanced, as the image-guided insertion technique will implicate a longer preparation time due to a specific image acquisition and trajectory planning

Evaluation of external ventricular drain complications and the use of a procedure-targeted image-guidance system

Thesis (S.M.)--Harvard-MIT Division of Health Sciences and Technology, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 55-59).Access to the cerebral ventricle (e.g. ventriculostomy) is required to manage multiple life-threatening ailments. It can be done either in the operating room or at the bedside to relieve increased intracranial pressure or deliver medication. At the bedside, the procedure is normally performed freehand, with the occasional use of a Ghajar guide for guidance support. In the operating room, ventriculostomy may be performed with an image-guidance system, whether optical or electromagnetic. The most common complications of ventriculostomy are hemorrhage and infection. It is unclear whether catheter placement accuracy and the number of passes of the catheter for each placement are correlated with ventriculostomy complications. Our goals are 1) to evaluate the current state of practice, including complications of ventriculostomy, and 2) to evaluate a targeted image guidance system for use with ventriculostomy - the Smart Stylet. To address these goals, an Institutional Review Board-approved retrospective cross-sectional study was conducted at the Brigham and Women's Hospital (BWH) to characterize the practice of external ventricular drain placements using data from the patient electronic medical record. Post-procedure catheter location was measured on post-procedure CT and MRI imaging studies. Most cases were performed in the operating room and the operative reports provided all procedure-related information. Microbiology reports were collected within a four-week interval following catheter placements to evaluate presence of invading pathogens. All imaging studies, microbiology reports, and operative reports were reviewed manually. The rest of the medical records were not reviewed and, therefore, cerebrospinal fluid leak and shunt malfunction were not evaluated. Catheter placement accuracy and the numbers of passes for each placement were assessed. We evaluated whether these metrics were associated with the occurrence of procedure complications. A procedure-targeted image guidance system in development stage, the Smart Stylet, was implemented for use on a ventricular phantom model with a right-sided midline shift. Smart Stylet consists of an electromagnetic tracking system and ventriculostomy catheter connected to a PC and display. The operator of the Smart Stylet can interface with the system via a custom designed module in BWH's 3DSlicer software system. The system was tested for accuracy by calculating targeting error and reporting the precision of catheter placement. Precision was measured using pair-wise distances among experimental groups. The system was reviewed and commented on by three novices and two neurosurgical residents from the Massachusetts General Hospital by using the NASA-TLX grading scale questionnaire and a targeted survey. The phantom model was designed to gauge whether further tests in animals and cadavers are warranted using Smart Stylet. Patients with trauma were more likely to have catheters misplaced (OR = 9.13±2.31; p<0.05). It seems there is an opportunity to improve patient care if catheter placement is made more accurate and reliable. Use of the Smart Stylet system in a phantom study provided improvements in mean pair-wise distance and accuracy for catheter placement at the sub-centimeter level. A blinded operator achieved statistically significant improvement in targeting error using the right frontal approach (p<0.0 5). The operator also significantly improved mean pairwise distances using left and right frontal approaches (p<0.05). Novice operators and neurosurgical residents both showed improvements in targeting accuracy for catheter placement when using the system for the first time. However, the improvements were not statistically significant. Novices' pair-wise distances were significantly better with Smart Stylet guidance using the left frontal approach (p<0.05). Improved guidance techniques, such as the Smart Stylet approach, can potentially decrease ventriculostomy complications if they can be easily integrated into clinical use at low cost.by Vaibhav Devidas Patil.S.M

3D Ultrasound in the Management of Post Hemorrhagic Ventricle Dilatation

Enlargement of the cerebral ventricles is relatively common among extremely preterm neonates born before 28 weeks gestational age. One common cause of ventricle dilatation is post hemorrhagic ventricle dilatation following a bleed in the cerebral ventricles. While many neonates with PHVD will have spontaneous resolution of the condition, severe, persistent PHVD is associated with a greater risk of brain injury and morbidity later in life and left untreated can cause death. The current clinical management strategy consists of daily measurements of head circumference and qualitative interpretation of two-dimensional US images to detect ventricular enlargement and monitoring vital signs for indications increased intracranial pressure (i.e. apnea, bradycardia). Despite the widespread clinical use of these indicators, they do not have the specificity to reliably indicate when an intervention to remove some CSF is required to prevent brain damage. Early recognition of interventional necessity using quantitative measurements could help with the management of the disease, and could lead to better care in the future. Our objective was to develop and validate a three-dimensional ultrasound system for use within an incubator of neonates with PHVD in order to accurately measure the cerebral ventricle volume. This system was validated against known geometric phantoms as well as a custom ventricle-like phantom. Once validated, the system was used in a clinical study of 70 neonates with PHVD to measure the ventricle size. In addition to three-dimensional ultrasound, clinical ultrasound images, and MRIs were attained. Clinical measurements of the ventricles and three-dimensional ultrasound ventricle volumes were used to determine thresholds between neonates with PHVD who did and did not receive interventions based on current clinical management. We determined image based thresholds for intervention for both neonates who will receive an initial intervention, as well as those who will receive multiple interventions. Three-dimensional ultrasound based ventricle volume measurements had high sensitivity and specificity as patients with persistent PHVD have ventricles that increase in size faster than those who undergo resolution. This allowed for delineation between interventional and non-interventional patients within the first week of life. While this is still a small sample size study, these results can give rise to larger studies that would be able to determine if earlier intervention can result in better neurodevelopmental outcomes later in life

Proof of Concept: Wearable Augmented Reality Video See-Through Display for Neuro-Endoscopy

In mini-invasive surgery and in endoscopic procedures, the surgeon operates without a direct visualization of the patient’s anatomy. In image-guided surgery, solutions based on wearable augmented reality (AR) represent the most promising ones. The authors describe the characteristics that an ideal Head Mounted Display (HMD) must have to guarantee safety and accuracy in AR-guided neurosurgical interventions and design the ideal virtual content for guiding crucial task in neuro endoscopic surgery. The selected sequence of AR content to obtain an effective guidance during surgery is tested in a Microsoft Hololens based app

Atrial Septal Defect

Atrial Septal Defects (ASDs) are relatively common both in children and adults. Recent reports of increase in the prevalence of ASD may be related use of color Doppler echocardiography. The etiology of the ASD is largely unknown. While the majority of the book addresses closure of ASDs, one chapter in particular focuses on creating atrial defects in the fetus with hypoplastic left heart syndrome. This book, I hope, will give the needed knowledge to the physician caring for infants, children, adults and elderly with ASD which may help them provide best possible care for their patients

Transcatheter Structural Heart Disease Interventions

This reprint focuses on the transcatheter treatment of the main structural heart diseases covering the latest innovations and hot topics on this subject. All the technological developments witnessed in recent decades have made structural heart disease interventions a growing field and have contributed to offering patients less invasive, more effective, and safe alternative approaches

Design and Development of a Lorentz Force-Based MRI-Driven Neuroendoscope

The introduction of neuroendoscopy, microneurosurgery, neuronavigation, and intraoperative imaging for surgical operations has made significant improvements over other traditionally invasive surgical techniques. The integration of magnetic resonance imaging (MRI)-driven surgical devices with intraoperative imaging and endoscopy can enable further advancements in surgical treatments and outcomes. This work proposes the design and development of an MRI-driven endoscope leveraging the high (3-7 T), external magnetic field of an MR scanner for heat-mitigated steering within the ventricular system of the brain. It also demonstrates the effectiveness of a Lorentz force-based grasper for diseased tissue manipulation and ablation. Feasibility studies show the neuroendoscope can be steered precisely within the lateral ventricle to locate a tumor using both MRI and endoscopic guidance. Results also indicate grasping forces as high as 31 mN are possible and power inputs as low as 0.69 mW can cause cancerous tissue ablation. These findings enable further developments of steerable devices using MR imaging integrated with endoscopic guidance for improved outcomes

Right ventricular performance in the cardiac surgical patient

In recent years there has been growing acknowledgement that the performance of the right ventricle (RV), which is an essential part of the cardiovascular system, plays a role in clinically relevant endpoints. In this thesis we aimed to improve the understanding of RV performance in the cardiosurgical patient. We demonstrated that postoperative right ventricular ejection fraction (RVEF), as assessed by contemporary pulmonary artery catheter, was a strong independent risk factor for long-term mortality. Impaired RVEF was not only associated with mortality directly after the surgical procedure, but its association continued to increase in the two years following the intervention. RVEF was additionally associated with markers of morbidity, such as length of stay in the intensive care unit (ICU), duration of mechanical ventilation, and increased use of inotropic drugs. The observed association between RVEF and outcome does not allow for conclusions on cause-effect relationship. We combined both invasive haemodynamic pulmonary artery catheter-monitoring with transoesophageal echocardiography. We observed that a significant reduction regional (longitudinal) echocardiographic parameters was not accompanied by a reduction in global measures of RV function. These data highlight that regional RV measurements in the postoperative cardiac surgical setting do not reflect global RV function, and should therefore be interpreted with caution. Managing patients with an impaired RV function is challenging. Although thought to be one of the cornerstones in the treatment of postoperative RV dysfunction, the increase in systemic blood pressure in patients with a moderate or poor RVEF and hypotension was shown to be ineffective in the clinical postoperative setting