Most Promising Approaches to Improve Brain AVM Management: ARISE I Consensus Recommendations

Brain arteriovenous malformations (bAVMs) are complex, and rare arteriovenous shunts that present with a wide range of signs and symptoms, with intracerebral hemorrhage being the most severe. Despite prior societal position statements, there is no consensus on the management of these lesions. ARISE (Aneurysm/bAVM/cSDH Roundtable Discussion With Industry and Stroke Experts) was convened to discuss evidence-based approaches and enhance our understanding of these complex lesions. ARISE identified the need to develop scales to predict the risk of rupture of bAVMs, and the use of common data elements to perform prospective registries and clinical studies. Additionally, the group underscored the need for comprehensive patient management with specialized centers with expertise in cranial and spinal microsurgery, neurological endovascular surgery, and stereotactic radiosurgery. The collection of prospective multicenter data and gross specimens was deemed essential for improving bAVM characterization, genetic evaluation, and phenotyping. Finally, bAVMs should be managed within a multidisciplinary framework, with clinical studies and research conducted collaboratively across multiple centers, harnessing the collective expertise and centralization of resources.

Reducing frame rate and pulse rate for routine diagnostic cerebral angiography: ALARA principles in practice

OBJECTIVE

Diagnostic cerebral angiograms (DCAs) are widely used in neurosurgery due to their high sensitivity and specificity to diagnose and characterize pathology using ionizing radiation. Eliminating unnecessary radiation is critical to reduce risk to patients, providers, and health care staff. We investigated if reducing pulse and frame rates during routine DCAs would decrease radiation burden without compromising image quality.

METHODS

We performed a retrospective review of prospectively acquired data after implementing a quality improvement protocol in which pulse rate and frame rate were reduced from 15 p/s to 7.5 p/s and 7.5 f/s to 4.0 f/s respectively. Radiation doses and exposures were calculated. Two endovascular neurosurgeons reviewed randomly selected angiograms of both doses and blindly assessed their quality.

RESULTS

A total of 40 consecutive angiograms were retrospectively analyzed, 20 prior to the protocol change and 20 after. After the intervention, radiation dose, radiation per run, total exposure, and exposure per run were all significantly decreased even after adjustment for BMI (all p<0.05). On multivariable analysis, we identified a 46% decrease in total radiation dose and 39% decrease in exposure without compromising image quality or procedure time.

CONCLUSIONS

We demonstrated that for routine DCAs, pulse rate of 7.5 with a frame rate of 4.0 is sufficient to obtain diagnostic information without compromising image quality or elongating procedure time. In the interest of patient, provider, and health care staff safety, we strongly encourage all interventionalists to be cognizant of radiation usage to avoid unnecessary radiation exposure and consequential health risks.

Standalone middle meningeal artery embolization versus middle meningeal artery embolization with concurrent surgical evacuation for chronic subdural hematomas: a multicenter propensity score matched analysis of clinical and radiographic outcomes

BACKGROUND

Middle meningeal artery embolization (MMAE) has emerged as a promising therapy for chronic subdural hematomas (cSDHs). The efficacy of standalone MMAE compared with MMAE with concurrent surgery is largely unknown.

METHODS

cSDH patients who underwent successful MMAE from 14 high volume centers with at least 30 days of follow-up were included. Clinical and radiographic variables were recorded and used to perform propensity score matching (PSM) of patients treated with standalone MMAE or MMAE with concurrent surgery. Multivariable logistic regression models were used for additional covariate adjustments. The primary outcome was recurrence requiring surgical rescue, and the secondary outcome was radiographic failure defined as <50% reduction of cSDH thickness.

RESULTS

722 MMAE procedures in 588 cSDH patients were identified. After PSM, 230 MMAE procedures remained (115 in each group). Median age was 73 years, 22.6% of patients were receiving anticoagulation medication, and 47.9% had no preoperative functional disability. Median midline shift was 4 mm and cSDH thickness was 16 mm, representing modestly sized cSDHs. Standalone MMAE and MMAE with surgery resulted in similar rates of surgical rescue (7.8% vs 13.0%, respectively, P=0.28; adjusted OR (aOR 0.73 (95% CI 0.20 to 2.40), P=0.60) and radiographic failure (15.5% vs 13.7%, respectively, P=0.84; aOR 1.08 (95% CI 0.37 to 2.19), P=0.88) with a median follow-up duration of 105 days. These results were similar across subgroup analyses and follow-up durations.

CONCLUSIONS

Standalone MMAE led to similar and durable clinical and radiographic outcomes as MMAE combined with surgery in select patients with moderately sized cSDHs and mild clinical disease.

How do children fare compared with adults? Comparing relative outcomes after thrombectomy for acute ischemic stroke due to large-vessel occlusion

OBJECTIVE

Safety and efficacy data for endovascular thrombectomy for acute ischemic stroke secondary to large-vessel occlusion in children are lacking compared with those for adults. We undertook an updated systematic review and meta-analysis of endovascular thrombectomy in children and compared their outcomes with adult data.

METHODS

We searched PubMed, Medline, and EMBASE databases to identify prospective and retrospective studies describing patients <18 years treated with endovascular thrombectomy for acute ischemic stroke due to large-vessel occlusion.

RESULTS

Eight pediatric studies were included (n = 192). Most patients were male (53.1 %), experienced anterior circulation large-vessel occlusion (81.8 %), and underwent endovascular thrombectomy by stent retreiver (70.7 %). The primary outcome was change in National Institutes of Health Stroke Scale score from presentation to 24 h after thrombectomy. Secondary outcomes included modified Rankin scale score improvement and 90-day score, recanalization rates, procedural complications, and mortality rates. After treatment, 88.5% of children had successful recanalization; the mean National Institutes of Health Stroke Scale score reduction was 7.37 (95 % CI 5.11-9.63, p < 0.01). The mean reduction of 6.87 (95 %CI 5.00-8.73, p < 0.01) for adults in 5 clinical trials (n = 634) was similar (Qb = 0.11; p = 0.74). Children experienced higher rates of good neurological outcome (76.1 % vs. 46.0 %, p < 0.01) and revascularization (88.5 % vs. 72.3 %, p < 0.01), fewer major periprocedural complications (3.6 % vs. 30.4 %, p < 0.01), and lower mortality (1.0 % vs. 12.9 %, p < 0.01).

CONCLUSIONS

Endovascular thrombectomy may be safe and effective treatment for acute ischemic stroke due to large-vessel occlusion in children. The aggregated data demonstrated high rates of revascularization, favorable long-term neurological outcomes, and low complication rates.

Soft robotic steerable microcatheter for the endovascular treatment of cerebral disorders

Catheters used for endovascular navigation in interventional procedures lack dexterity at the distal tip. Neurointerventionists, in particular, encounter challenges in up to 25% of aneurysm cases largely due to the inability to steer and navigate the tip of the microcatheters through tortuous vasculature to access aneurysms. We overcome this problem with submillimeter diameter, hydraulically actuated hyperelastic polymer devices at the distal tip of microcatheters to enable active steerability. Controlled by hand, the devices offer complete 3D orientation of the tip. Using saline as a working fluid, we demonstrate guidewire-free navigation, access, and coil deployment in vivo, offering safety, ease of use, and design flexibility absent in other approaches to endovascular intervention. We demonstrate the ability of our device to navigate through vessels and to deliver embolization coils to the cerebral vessels in a live porcine model. This indicates the potential for microhydraulic soft robotics to solve difficult access and treatment problems in endovascular intervention.

Tentorial sling for microvascular decompression in patients with trigeminal neuralgia: a description of operative technique and clinical outcomes

OBJECTIVE

Trigeminal neuralgia is a debilitating pain disorder most often caused by arterial compression of the trigeminal nerve, although there are other etiologies. Microvascular decompression (MVD) remains the most definitive treatment for this disorder, with cure rates reported between 60% and 80%. Traditional MVD techniques involve a retrosigmoid craniotomy with placement of an inert foreign material, such as Teflon, between the nerve and compressive vessel. Recurrence of trigeminal neuralgia after MVD has been associated with vessel migration, adhesion formation, and arterial pulsation against the Teflon abutting the nerve. Additionally, foreign materials such as Teflon have been reported to trigger inflammatory responses, resulting in recurrence of trigeminal pain. An alternative method for decompression involves the use of a sling to transpose the compressive vessel away from the nerve. Results of various sling techniques as a decompressive strategy are limited to small series and case reports. In this study, the authors present their experience utilizing a tentorial sling for MVD in patients with trigeminal neuralgia.

METHODS

Institutional review board approval was obtained in order to contact patients who underwent MVD for trigeminal neuralgia via the tentorial sling technique. Clinical outcomes were assessed utilizing the Barrow Neurological Institute (BNI) pain intensity score immediately after surgery and at the time of the study.

RESULTS

The tentorial sling technique was performed in 45 patients undergoing MVD for trigeminal neuralgia. In 41 of these patients, this procedure was their first decompressive surgery. Immediate postoperative relief of pain (BNI score I) was achieved in 80% of patients undergoing their first decompressive procedure. At last follow-up, 73% of these patients remained pain free. Three patients experienced recurrent trigeminal pain, with surgical exploration demonstrating an intact tentorial sling. The complication rate was 6.6%.

CONCLUSIONS

Transposition techniques for MVD have been described previously in small series and case reports. This study represents the largest experience in which the utilization of a tentorial sling for MVD in patients with trigeminal neuralgia is described. The technique represents a novel method for decompression of the trigeminal nerve by transposition of the offending vessel without the use of foreign material. Although the authors’ preliminary results parallel the historical cure rate, further outcome data are required to assess long-term durability of this method.

Abstract TP286: Efficacy of Quality Improvement Protocols Across Diverse Modes of Arrival for Thrombectomy Patients With Ischemic Stroke

Background: Quality improvement protocols (QI) aim to reduce in-hospital delays that result in prolonged door-to-groin-puncture time (DGPT) for the endovascular treatment of ischemic stroke. At our institution, we implemented a comprehensive QI protocol to reduce DGPT from June 2015 to December 2016. Here we discuss the QI protocol on DGPT across diverse modes of arrival to our interventional suite.

Methods: 61 patients underwent mechanical thrombectomy for ischemic stroke during our QI period. Independent samples t-tests were used to investigate differences in DGPT early in the QI protocol (July 2015 to February 2016, n=30) versus late in the QI protocol (March 2016 to December 2016, n=31) for patients that presented via emergency medical services (EMS), inpatient, and hospital transfers.

Results: Each mode of arrival demonstrated reductions in DGPT (Figure 1). The greatest reduction in DGPT was for the 23 patients within the emergency medical services (EMS) group with a mean reduction of 39 minutes which approached, but didn’t achieve, statistical significance (138 vs. 99; p=0.06).

Discussion: QI interventions impact DGPT across different patient arrival methods. QI protocols accounting for patient presentation allow tailored approaches to institutional measures to reduce DGPT.

Abstract 050: Improvements in Door to Groin Puncture Time for Surgical Stroke After Quality Protocol Interventions at the University of California, San Diego

Introduction: Delays in door to groin puncture time (DGPT) for patients with ischemic stroke caused by acute large vessel occlusion (LVO) correlate with worse clinical outcomes. Stroke centers aim to minimize DGPT to facilitate prompt intervention and limit ischemic brain injury. In this study, we present the results of a comprehensive quality assessment at the University of California, San Diego (UCSD). From 2015 to 2016, institutional implementation of a quality improvement protocol significantly reduced DGPT.

Materials and Methods: Beginning July 2015, the UCSD interdisciplinary stroke team implemented a series of quality improvement measures to decrease DGPT, with a target of 90 minutes or less. After each case, areas of inefficiency were identified and changes were implemented based on direct feedback from neurointerventional physicians and ancillary staff. Changes included: 1) creation of a pager group notification system to activate the entire neurointerventional team simultaneously, 2) consistently involving anesthesia with each neurointervention, 3) streamlining communication between the vascular neurology and neurointervention teams, and 4) structuring parallel workflows to enhance mobilization speed. R statistical software was utilized to compare DGPT before and after implementation of these process improvements. Patients were divided into three groups based on the date of their intervention as follows: 23 patients treated from July-December 2015, 24 patients treated from January-July 2016, and 14 patients treated from July 2016-December 2016. A multivariable univariate binary logistic regression model was constructed to capture predictors of compliance with our target DGPT (<90 min). Variables analyzed included: date of intervention, mode of patient admission (i.e. transfer, direct admit from ED, inpatient), hospital location, age, and gender.

Results: 61 patients underwent mechanical thrombectomy for treatment of acute LVO from July 2015 to December 2016. In our analysis, date of intervention—as a proxy for implementation of process improvement protocols—and mode of admission were predictive of compliance with target DGPT. Patients who were treated from July 2016 to December 2016—after full implementation of process improvements— were 9.5 times more likely to meet or exceed the target DGPT compared to patients treated July 2015 to December 2015 (p=0.01). Additionally, arrival via transfer from an outside hospital was determined to be an independent predictor of meeting DGPT goals. (p=0.02).

Conclusion: UCSD’s quality improvement process effected dramatic, statistically significant improvement in DGPT. This analysis demonstrates the utility of a formal quality improvement system at a large, academic comprehensive stroke center.

Vessel-preserving stent-assisted coil embolization of an extracranial internal carotid artery pseudoaneurysm that developed after tonsillectomy in a pediatric patient: initial case report

Although there have been reports of carotid artery pseudoaneurysm formation after adenoidectomy and/or tonsillectomy secondary to iatrogenic injury, there are no case reports of successful endovascular reconstruction of the injured artery in the pediatric population. In most pediatric cases, the internal carotid artery (ICA) is sacrificed. The authors report on a 6-year-old girl who presented with odynophagia, left-sided Horner's syndrome, hematemesis, and severe anemia 6 months after a tonsillectomy. On examination she was found to have a pulsatile mass along the left posterior lateral oropharynx, and imaging demonstrated a dissection of the extracranial left ICA and an associated pseudoaneurysm. The lesion was managed endovascularly with stent-assisted coil embolization and ICA reconstruction. The child had a somewhat complicated postoperative course, requiring additional coil embolization for treatment of a minor recurrence of the pseudoaneurysm at 5 months after the initial treatment and then presenting with extrusion of a portion of the coil mass into the oropharyngeal cavity a year later. She underwent surgical removal of the extruded coils and repair of the defect and has since been free of symptoms or signs of recurrence. The authors conclude that this strategy definitively protected the patient against an oral exsanguination or aspiration event secondary to aneurysm rupture and reduced her risk of stroke by preserving vessel patency and caliber. Moreover, they note that covered stent reconstruction surrenders endovascular access and cannot immediately provide these benefits.

Initial multicenter technical experience with the Apollo device for minimally invasive intracerebral hematoma evacuation

BACKGROUND

No conventional surgical intervention has been shown to improve outcomes for patients with spontaneous intracerebral hemorrhage (ICH) compared with medical management.

OBJECTIVE

We report the initial multicenter experience with a novel technique for the minimally invasive evacuation of ICH using the Penumbra Apollo system (Penumbra Inc, Alameda, California).

METHODS

Institutional databases were queried to perform a retrospective analysis of all patients who underwent ICH evacuation with the Apollo system from May 2014 to September 2014 at 4 centers (Medical University of South Carolina, Stony Brook University, University of California at San Diego, and Semmes-Murphy Clinic). Cases were performed either in the neurointerventional suite, operating room, or in a hybrid operating room/angiography suite.

RESULTS

Twenty-nine patients (15 female; mean age, 62 ± 12.6 years) underwent the minimally invasive evacuation of ICH. Six of these parenchymal hemorrhages had an additional intraventricular hemorrhage component. The mean volume of ICH was 45.4 ± 30.8 mL, which decreased to 21.8 ± 23.6 mL after evacuation (mean, 54.1 ± 39.1% reduction; P < .001). Two complications directly attributed to the evacuation attempt were encountered (6.9%). The mortality rate was 13.8% (n = 4).

CONCLUSION

Minimally invasive evacuation of ICH and intraventricular hemorrhage can be achieved with the Apollo system. Future work will be required to determine which subset of patients are most likely to benefit from this promising technology.

A proposed grading system for standardizing tumor consistency of intracranial meningiomas

Object

Tumor consistency plays an important and underrecognized role in the surgeon's ability to resect meningiomas, especially with evolving trends toward minimally invasive and keyhole surgical approaches. Aside from descriptors such as “hard” or “soft,” no objective criteria exist for grading, studying, and conveying the consistency of meningiomas.

Methods

The authors designed a practical 5-point scale for intraoperative grading of meningiomas based on the surgeon's ability to internally debulk the tumor and on the subsequent resistance to folding of the tumor capsule. Tumor consistency grades and features are as follows: 1) extremely soft tumor, internal debulking with suction only; 2) soft tumor, internal debulking mostly with suction, and remaining fibrous strands resected with easily folded capsule; 3) average consistency, tumor cannot be freely suctioned and requires mechanical debulking, and the capsule then folds with relative ease; 4) firm tumor, high degree of mechanical debulking required, and capsule remains difficult to fold; and 5) extremely firm, calcified tumor, approaches density of bone, and capsule does not fold. Additional grading categories included tumor heterogeneity (with minimum and maximum consistency scores) and a 3-point vascularity score. This grading system was prospectively assessed in 50 consecutive patients undergoing craniotomy for meningioma resection by 2 surgeons in an independent fashion. Grading scores were subjected to a linear weighted kappa analysis for interuser reliability.

Results

Fifty patients (100 scores) were included in the analysis. The mean maximal tumor diameter was 4.3 cm. The distribution of overall tumor consistency scores was as follows: Grade 1, 4%; Grade 2, 9%; Grade 3, 43%; Grade 4, 44%; and Grade 5, 0%. Regions of Grade 5 consistency were reported only focally in 14% of heterogeneous tumors. Tumors were designated as homogeneous in 68% and heterogeneous in 32% of grades. The kappa analysis score for overall tumor consistency grade was 0.87 (SE 0.06, 95% CI 0.76–0.99), with 90% user agreement. Kappa analysis scores for minimum and maximum grades of tumor regions were 0.69 (agreement 72%) and 0.75 (agreement 78%), respectively. The kappa analysis score for tumor vascularity grading was 0.56 (agreement 76%). Overall consistency did not correlate with patient age, tumor location, or tumor size. A higher tumor vascularity grade was associated with a larger tumor diameter (p = 0.045) and with skull base location (p = 0.02).

Conclusions

The proposed grading system provides a reliable, practical, and objective assessment of meningioma consistency and facilitates communication among providers. This system also accounts for heterogeneity in tumor consistency. With the proposed scale, meningioma consistency can be standardized as groundwork for future studies relating to surgical outcomes, predictability of consistency and vascularity using neuroimaging techniques, and effectiveness of various surgical instruments.

Spinal cord stimulator adjustment to maximize implanted battery longevity: a randomized, controlled trial using a computerized, patient-interactive programmer

Internally powered, implanted pulse generators (IPGs) have been an important advance in spinal cord stimulation for the management of pain, but they require surgical replacement, with attendant cost and risk, when the implanted battery is depleted. Battery life is determined by the programmed settings of the implant, but until now the technical means to optimize settings for maximal battery life, delaying surgical replacement as long as possible, Materials and Methods.  We have developed a patient-interactive, computerized programmer for use with IPGs. It has been designed for easy operation and comprehensive data management, which have not been features of the standard programmers available until now. It automatically and rapidly presents to the patient a sequence of settings (contact combinations and pulse parameters) specified by the practitioner. Test results are analyzed and sorted to determine the optimal settings by multiple criteria, including battery life. In the present study we used new, improved algorithms to estimate battery life.  We have compared the computerized, patient-interactive system with standard practitioner-operated, manual programming methods in a randomized, controlled trial in 44 patients at two study centers.  In 95% of patients (41/43), the computerized, patient-interactive system identified new settings with improved estimated battery life (and corresponding anticipated cost savings) which had not been recognized as such using manual methods. The estimated battery life for the setting chosen by each patient using manual methods averaged 25.4 ± 49.5 (mean ± standard deviation) months; the longest battery life identified by computerized methods averaged 55.0 ± 71.7, a 2.2-fold or 29.6 month improvement. Seventy-two percent of patients (31/43) achieved better battery life at settings with technical results (visual analog scale rating of overlap or coverage of pain by stimulation paresthesias) equal or superior to those achieved by manual methods. The overall improvement over the setting chosen by manual methods was 1.41-fold or 10.5 months; averaged by patient, the improvement was 1.63-fold. Estimated cost savings averaged just over one-third. As reported previously, the new system also yields significantly (p < 0.0001) better technical results than traditional, manual methods in achieving coverage of pain by stimulation paresthesias; the very best technical results were achieved at some expense in estimated battery life (assuming the same frequency of use). We conclude that significant potential savings in longevity of the implanted battery are possible in the majority of patients with implanted spinal cord stimulators, but have not been realized until now for lack of appropriate methods. Computerized, patient-interactive programming addresses this problem and allows optimization of estimated battery life along with other treatment goals. Long-term clinical followup will be required to establish the full magnitude of the resulting savings.

Intraventricular ganglioglioma: a short illustrated review

The following review of the literature describes the ganglioglioma, an uncommon mixed glioneuronal neoplasm, most often of low-grade histology, with a small, albeit well-documented, malignant potential. These tumors exhibit a strong epileptogenic propensity and most often present as new onset seizures or are discovered after a long history of refractory epilepsy. Despite their indolent course, the importance of gross total resection is well recognized to prevent anaplastic and malignant degeneration. Morphologically, the neoplasm is often cystic with an enhancing mural nodule, but can also be entirely solid. They are most often found in the temporal lobe but have been found throughout the neuraxis. An exceedingly rare location of the ganglioglioma is within the lateral ventricle. A systematic literature search revealed only eight reports documenting the occurrence of a ganglioglioma within the lateral ventricle. We describe an illustrative case of an intraventricular ganglioglioma with a prominent cystic component and enhancing mural nodule, which represents the classic radiographic appearance of gangliogliomas described in other locations. A superior parietal lobule approach offered excellent surgical access for tumor removal and the patient has remained free of neurological deficits following surgery. Regardless of location within the central nervous system, ganglioglioma should be on the differential diagnosis for any cystic mass with a mural nodule, particularly in the setting of epilepsy.