Neuromate® robot-assisted ventricular catheter insertion

BACKGROUND AND IMPORTANCE

Insertion of ventricular catheters into small ventricles may require image guidance. Several options exist, including ultrasound guidance, frameless, and frame-based stereotactic approaches. There is no literature on management options when conventional image guidance fails to cannulate the ventricle. The accuracy of the robotic arm is well established in functional and epilepsy surgery. We report the first case using the Neuromate® robot for the placement of a shunt ventricular catheter into the lateral ventricle after a failed attempt with a more commonly used frameless electromagnetic navigation system.

CLINICAL PRESENTATION

A 30-year-old man had twice previously undergone foramen magnum decompression for a Chiari 1 malformation. He subsequently developed a significant cervical syrinx with clinical deterioration and a decision was made to place a ventriculoperitoneal shunt. As the ventricles were small, frameless electromagnetic navigation was used but the ventricle could not be cannulated. The Neuromate® robot was subsequently used to place the ventricular catheter successfully.

CONCLUSION

Neuromate® robot-assisted ventricular catheter placement may be considered when difficulty is experienced with more commonly used image guidance techniques.

Improved Accuracy and Lowered Learning Curve of Ventricular Targeting Using Augmented Reality-Phantom and Cadaveric Model Testing

BACKGROUND

Augmented reality (AR) has demonstrated significant potential in neurosurgical cranial, spine, and teaching applications. External ventricular drain (EVD) placement remains a common procedure, but with error rates in targeting between 10% and 40%.

OBJECTIVE

To evaluate Novarad VisAR guidance system for the placement of EVDs in phantom and cadaveric models.

METHODS

Two synthetic ventricular phantom models and a third cadaver model underwent computerized tomography imaging and registration with the VisAR system (Novarad). Root mean square (RMS), angular error (γ), and Euclidian distance were measured by multiple methods for various standard EVD placements.

RESULTS

Computerized tomography measurements on a phantom model (0.5-mm targets showed a mean Euclidean distance error of 1.20 ± 0.98 mm and γ of 1.25° ± 1.02°. Eight participants placed EVDs in lateral and occipital burr holes using VisAR in a second phantom anatomic ventricular model (mean RMS: 3.9 ± 1.8 mm, γ: 3.95° ± 1.78°). There were no statistically significant differences in accuracy for postgraduate year level, prior AR experience, prior EVD experience, or experience with video games ( P > .05). In comparing EVDs placed with anatomic landmarks vs VisAR navigation in a cadaver, VisAR demonstrated significantly better RMS and γ, 7.47 ± 0.94 mm and 7.12° ± 0.97°, respectively ( P ≤ .05).

CONCLUSION

The novel VisAR AR system resulted in accurate placement of EVDs with a rapid learning curve, which may improve clinical treatment and patient safety. Future applications of VisAR can be expanded to other cranial procedures.

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.

Anterior versus Posterior Ventricular Catheter Placement in Pediatric Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Ventriculoperitoneal shunt placement is the mainstay of treatment for hydrocephalus, but there are relatively high rates of malfunction. Shunt catheter entry can be performed anteriorly or posteriorly, with the body of evidence from randomized controlled trials and retrospective studies suggesting conflicting findings.

METHODS

A systematic review of PubMed, Medline, Scopus, and Web of Science was performed adherent to PRISMA guidelines, searching for clinical studies examining outcomes for anterior or frontal and posterior or occipital ventriculoperitoneal shunt placement. A random-effects model meta-analysis was performed on R.

RESULTS

Six studies (2 randomized controlled trials and 4 retrospective cohort studies) comprising 1808 patients were identified. There were no statistically significant differences between anterior and posterior ventriculoperitoneal shunt placement for the outcomes of poor catheter placement (odds ratio [OR], 0.74; P = 0.6) and shunt infections (OR, 1.01; P = 0.9). Posterior shunts trended toward greater number of shunt revisions (OR, 0.72; P = 0.06). Six and 12 months shunt survival was comparable between anterior and posterior approaches (P > 0.05). There were significant differences between long-term shunt survival (2 and 5 years shunt survival), favoring anterior shunt placement with greater odds of survival (OR, 1.91 and OR, 1.62, respectively; P < 0.05).

CONCLUSIONS

We show that although anteriorly and posteriorly placed shunts have mostly comparable outcomes, shunt survival at 2-year and 5-year intervals favors anteriorly placed shunts. Additional well-designed clinical trials are needed to validate the findings of greater late shunt failure in posteriorly placed shunts, with more time-dependent statistical measures.

Cerebrospinal Fluid Shunting for Idiopathic Intracranial Hypertension: A Systematic Review, Meta-Analysis, and Implications for a Modern Management Protocol

BACKGROUND

Cerebrospinal fluid (CSF) shunting is widely used in refractory idiopathic intracranial hypotension (IIH). Although multiple reviews have assessed its efficacy compared with other surgical treatments, there is no detailed analysis that evaluates the clinical outcomes after CSF shunting.

OBJECTIVE

To conduct a meta-analysis of the clinical impact of CSF shunting for refractory IIH and use this in conjunction with existing information on other treatment modalities to develop a modern management protocol.

METHODS

PubMed and Embase were systematically searched for studies describing CSF shunting for medically refractory IIH. Relevant information including study characteristics, patient demographics, clinical outcomes, periprocedural complications, and long-term outcomes were subjected to meta-analysis.

RESULTS

Fifteen studies published between 1988 and 2019 met our inclusion and exclusion criteria, providing 372 patients for analysis. The mean age was 31.2 years (range 0.5-71) with 83.6% being female. The average follow-up was 33.9 months (range 0-278 months). The overall rate of improvement in headache, papilledema, and visual impairment was 91% (95% CI 84%-97%), 96% (95% CI 85%-100%), and 85% (95% CI 72%-95%), respectively. Of 372 patients, 155 had 436 revisions; the overall revision rate was 42% (95% CI 26%-59%). There was no significant correlation between average follow-up duration and revision rates in studies ( P = .627). Periprocedural low-pressure headaches were noted in 74 patients (20%; 95% CI 11%-32%).

CONCLUSION

CSF shunting for IIH is associated with significant improvement in clinical symptoms. Shunting rarely causes periprocedural complications except overdrainage-related low-pressure headache. However, CSF shunting has a relatively high revision rate.

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

INTRODUCTION

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

METHODS

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

RESULT

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

CONCLUSION

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

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Neurosurgical CSF Diversion in Idiopathic Intracranial Hypertension: A Narrative Review

The prevalence of idiopathic intracranial hypertension (IIH), a complex disorder, is increasing globally in association with obesity. The IIH syndrome occurs as the result of elevated intracranial pressure, which can cause permanent visual impairment and loss if not adequately managed. CSF diversion via ventriculoperitoneal and lumboperitoneal shunts is a well-established strategy to protect vision in medically refractory cases. Success of CSF diversion is compromised by high rates of complication; including over-drainage, obstruction, and infection. This review outlines currently used techniques and technologies in the management of IIH. Neurosurgical CSF diversion is a vital component of the multidisciplinary management of IIH.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Emergency department observation of mild traumatic brain injury with minor radiographic findings: shorter stays, less expensive, and no increased risk compared to hospital admission

OBJECTIVE

The management of mild traumatic brain injury (mTBI) with minor radiographic findings traditionally involves hospital admission for monitoring, although this practice is expensive with unclear benefit. We implemented a protocol to manage these patients in our emergency department observation unit (EDOU), hypothesizing that this pathway was cost effective and not associated with any difference in clinical outcome.

METHODS

mTBI patients with minor radiographic findings were managed under the EDOU protocol over a 3-year period from May 1, 2015 to April 30, 2018 (inclusions: ≥19 years old, isolated acute head trauma, normal neurological exam [except transient alteration in consciousness], and a computed tomography [CT] scan of the head with at least 1 of the following: cerebral contusions <1 cm in maximum extent, convexity subarachnoid hemorrhage, or closed, non-displaced skull fractures). These patients were retrospectively analyzed; clinical outcomes and charges were compared to a control cohort of matched mTBI hospital admissions over the preceding 3 years.

RESULTS

Sixty patients were observed in the EDOU over the 3-year period, and 85 patients were identified for the control cohort. There were no differences in rate of radiographic progression, neurological exam change, or surgical intervention, and the overall incidence of hemorrhagic expansion was low in both groups. The EDOU group had a significantly faster time to interval CT scan (Mean Difference (MD) 3.92 hours, [95%CI 1.65, 6.19]), P = 0.001), shorter length of stay (MD 0.59 days [95% CI 0.29, 0.89], P = 0.001), and lower encounter charges (MD $3428.51 [95%CI 925.60, 5931.42], P = 0.008). There were no differences in 30-day re-admission, 30-day mortality, or delayed chronic subdural formation, although there was a high rate of loss to follow-up in both groups.

CONCLUSIONS

Compared to hospital admission, observing mTBI patients with minor radiographic findings in the EDOU was associated with significantly shorter time to interval scanning, shorter length of stay, and lower encounter charges, but no difference in observed clinical outcome. The overall risk of hemorrhagic progression in this subset of mTBI was very low. Using this approach can reduce unnecessary admissions while potentially yielding patient care and economic benefits. When designing a protocol, close attention should be given to clear inclusion criteria and a formal mechanism for patient follow-up.

Shunt Failure-The First 30 Days

BACKGROUND

Incontrovertible predictors of shunt malfunction remain elusive.

OBJECTIVE

To determine predictors of shunt failure within 30 d of index surgery.

METHODS

This was a single-center retrospective cohort study from January 2010 through November 2016. Using a ventricular shunt surgery research database, clinical and procedural variables were procured. An "index surgery" was defined as implantation of a new shunt or revision or augmentation of an existing shunt system. The primary outcome was shunt failure of any kind within the first 30 days of index surgery. Bivariate models were created, followed by a final multivariable logistic regression model using a backward-forward selection procedure.

RESULTS

Our dataset contained 655 unique patients with a total of 1206 operations. The median age for the cohort at the time of first shunt surgery was 4.6 yr (range, 0-28; first and third quartile, .37 and 11.8, respectively). The 30-day failure rates were 12.4% when analyzing the first-index operation only (81/655), and 15.7% when analyzing all-index operations (189/1206). Small or slit ventricles at the time of index surgery and prior ventricular shunt operations were found to be significant covariates in both the "first-index" (P < .01 and P = .05, respectively) and "all-index" (P = .02 and P < .01, respectively) multivariable models. Intraventricular hemorrhage at the time of index surgery was an additional predictor in the all-index model (P = .01).

CONCLUSION

This study demonstrates that only 3 variables are predictive of 30-day shunt failure when following established variable selection procedures, 2 of which are potentially under direct control of the surgeon.

Evaluating Shunt Survival Following Ventriculoperitoneal Shunting with and without Stereotactic Navigation in Previously Shunt-Naïve Patients

BACKGROUND

Ventriculoperitoneal shunts are used to alleviate elevated intracranial pressure due to either hydrocephalus or idiopathic intracranial hypertension; however, shunt failure is a significant neurosurgical problem. Despite increases in intraoperative stereotactic navigation usage over the past decade, its effect on shunt survival remains unclear.

METHODS

Shunt-naïve pediatric and adult patients receiving ventriculoperitoneal shunting between 2007 and 2015 were identified in a national administrative database. Multivariable logistic and Cox regressions were used to evaluate factors affecting stereotaxy usage and shunt survival. Matched cohorts were generated by propensity score balancing.

RESULTS

Of 9677 patients identified, 932 received image-guided shunt placement. Total shunt failure rate was not associated with stereotaxy use (20.3% with stereotaxy vs. 19.4% without, P = 0.4602). In the matched setting, shunt survival was not extended by use of image guidance during placement (hazard ratio = 1.134, 95% confidence interval 0.923-1.393). Late shunt failures (defined as failures occurring at least 30 days after shunt placement) caused by infection occurred more frequently in the stereotaxy cohort (hazard ratio = 2.207, 95% confidence interval 1.115-4.366), whereas late shunt failures attributable to mechanical shunt failure were more common in the nonstereotaxy cohort (hazard ratio = 1.406, 95% confidence interval 1.002-1.973).

CONCLUSIONS

Our findings suggest stereotaxy use during ventriculoperitoneal shunt placement does not affect shunt survival. Late shunt failures caused by infection occurred more frequently in the stereotaxy cohort, whereas late failures caused by mechanical shunt malfunction were more commonly encountered in the nonstereotaxy cohort.

Image Guidance for Ventricular Shunt Surgery: An Analysis of Hospital Charges

BACKGROUND

Image guidance for shunt surgery results in more accurate proximal catheter placement. However, reduction in shunt failure remains unclear in the literature. There have been no prior studies evaluating the cost effectiveness of neuronavigation for shunt surgery.

OBJECTIVE

To perform a cost analysis using available hospital charges of hypothetical shunt surgery performed with/without electromagnetic neuronavigation (EMN).

METHODS

Hospital charges were collected for physician fees, radiology, operating room (OR) time and supplies, postanesthesia care unit, hospitalization days, laboratory, and medications. Index shunt surgery charges (de novo or revision) were totaled and the difference calculated. This difference was compared with hospital charges for shunt revision surgery performed under 2 clinical scenarios: (1) same hospital stay as the index surgery; and (2) readmission through the emergency department.

RESULTS

Costs for freehand de novo and revision shunt surgery were $23 946.22 and $23 359.22, respectively. For stealth-guided de novo and revision surgery, the costs were $33 646.94 and $33 059.94, a difference of $9700.72. The largest charge increase was due to additional OR time (34 min; $4794), followed by disposable EMN equipment ($2672). Total effective charges to revise the shunt for scenarios 1 and 2 were $34 622.94 and $35 934.94, respectively. The cost ratios between the total revision charges for both scenarios and the difference in freehand vs EMN-assisted shunt surgery ($9700.72) were 3.57 and 3.70, respectively.

CONCLUSION

From an economic standpoint and within the limitations of our models, the number needed to prevent must be 4 or less for the use of neuronavigation to be considered cost effective.