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Objective: Despite advancement of thrombectomy technologies for large-vessel occlusion (LVO) stroke and increased user experience, complete recanalization rates linger around 50%, and one-third of patients who have undergone successful recanalization still experience poor neurological outcomes. To enhance the understanding of the biomechanics and failure modes, the authors conducted an experimental analysis of the interaction of emboli/artery/devices in the first human brain test platform for LVO stroke described to date., Methods: In 12 fresh human brains, 105 LVOs were recreated by embolizing engineered emboli analogs and recanalization was attempted using aspiration catheters and/or stent retrievers. The complex mechanical interaction between diverse emboli (elastic, stiff, and fragment prone), arteries (anterior and posterior circulation), and thrombectomy devices were observed, analyzed, and categorized. The authors systematically evaluated the recanalization process through failure modes and effects analysis, and they identified where and how thrombectomy devices fail and the impact of device failure., Results: The first-pass effect (34%), successful (71%), and complete (60%) recanalization rates in this model were consistent with those in the literature. Failure mode analysis of 184 passes with thrombectomy devices revealed the following. 1) Devices loaded the emboli with tensile forces leading to elongation and intravascular fragmentation. 2) In the presence of anterograde flow, small fragments embolize to the microcirculation and large fragments result in recurrent vessel occlusion. 3) Multiple passes are required due to recurrent (15%) and residual (73%) occlusions, or both (12%). 4) Residual emboli remained in small branching and perforating arteries in cases of alleged complete recanalization (28%). 5) Vacuum caused arterial collapse at physiological pressures (27%). 6) Device withdrawal caused arterial traction (41%), and severe traction provoked avulsion of perforating and small branching arteries., Conclusions: Biomechanically superior thrombectomy technologies should prevent unrestrained tensional load on emboli, minimize intraluminal embolus fragmentation and release, improve device/embolus integration, recanalize small branching and perforating arteries, prevent arterial collapse, and minimize traction.

Objective: The development of new endovascular technologies and techniques for mechanical thrombectomy in stroke has greatly relied on benchtop simulators. This paper presents an affordable, versatile, and realistic benchtop simulation model for stroke., Methods: A test bed for embolic occlusion of cerebrovascular arteries and mechanical thrombectomy was developed with 3D-printed and commercially available cerebrovascular phantoms, a customized hydraulic system to generate physiological flow rate and pressure, and 2 types of embolus analogs (elastic and fragment-prone) capable of causing embolic occlusions under physiological flow., Results: The test bed was highly versatile and allowed realistic, radiation-free mechanical thrombectomy for stroke due to large-vessel occlusion with rapid exchange of geometries and phantom types. Of the transparent cerebrovascular phantoms tested, the 3D-printed phantom was the easiest to manufacture, the glass model offered the best visibility of the interaction between embolus and thrombectomy device, and the flexible model most accurately mimicked the endovascular system during device navigation. None of the phantoms modeled branches smaller than 1 mm or perforating arteries, and none underwent realistic deformation or luminal collapse from device manipulation or vacuum. The hydraulic system created physiological flow rate and pressure leading to iatrogenic embolization during thrombectomy in all phantoms. Embolus analogs with known fabrication technique, structure, and tensile strength were introduced and consistently occluded the middle cerebral artery bifurcation under physiological flow, and their interaction with the device was accurately visualized., Conclusions: The test bed presented in this study is a low-cost, comprehensive, realistic, and versatile platform that enabled high-quality analysis of embolus-device interaction in multiple cerebrovascular phantoms and embolus analogs.

Objective: It is unknown what proportion of patients who undergo emergent neurosurgical procedures initiate comfort care (CC) measures shortly after the operation. The purpose of the present study was to analyze the proportion and predictive factors of patients who initiated CC measures within the same hospital admission after undergoing emergent neurosurgery., Methods: This retrospective cohort study included all adult patients who underwent emergent neurosurgical and endovascular procedures at a single center between 2009 and 2014. Primary and secondary outcomes were initiation of CC measures during the initial hospitalization and determination of predictive factors, respectively., Results: Of the 1295 operations, comfort care was initiated in 111 (8.6%) during the initial admission. On average, CC was initiated 9.3 ± 10.0 days postoperatively. One-third of the patients switched to CC within 3 days. In multivariate analysis, patients > 70 years of age were significantly more likely to undergo CC than those < 50 years (70-79 years, p = 0.004; > 80 years, p = 0.0001). Two-thirds of CC patients had been admitted with a cerebrovascular pathology (p < 0.001). Admission diagnosis of cerebrovascular pathology was a significant predictor of initiating CC (p < 0.0001). A high Hunt and Hess grade of IV or V in patients with subarachnoid hemorrhage was significantly associated with initiation of CC compared to a low grade (27.1% vs 2.9%, p < 0.001). Surgery starting between 15:01 and 06:59 hours had a 1.70 times greater odds of initiating CC compared to surgery between 07:00 and 15:00., Conclusions: Initiation of CC after emergent neurosurgical and endovascular procedures is relatively common, particularly when an elderly patient presents with a cerebrovascular pathology after typical operating hours.

Objective: Gastrostomy tube placement can temporarily seed the peritoneal cavity with bacteria and thus theoretically increases the risk of shunt infection when the two procedures are performed contemporaneously. The authors hypothesized that gastrostomy tube placement would not increase the risk of ventriculoperitoneal shunt infection. The object of this study was to test this hypothesis by utilizing a large patient cohort combined from multiple institutions., Methods: A retrospective study of all adult patients admitted to five institutions with a diagnosis of aneurysmal subarachnoid hemorrhage between January 2005 and January 2015 was performed. The primary outcome of interest was ventriculoperitoneal shunt infection. Variables, including gastrostomy tube placement, were tested for their association with this outcome. Standard statistical methods were utilized., Results: The overall cohort consisted of 432 patients, 47% of whom had undergone placement of a gastrostomy tube. The overall shunt infection rate was 9%. The only variable that predicted shunt infection was gastrostomy tube placement (p = 0.03, OR 2.09, 95% CI 1.07-4.08), which remained significant in the multivariate analysis (p = 0.04, OR 2.03, 95% CI 1.04-3.97). The greatest proportion of shunts that became infected had been placed more than 2 weeks (25%) and 1-2 weeks (18%) prior to gastrostomy tube placement, but the temporal relationship between shunt and gastrostomy was not a significant predictor of shunt infection., Conclusions: Gastrostomy tube placement significantly increases the risk of ventriculoperitoneal shunt infection.

Objective: Histotripsy is an ultrasound-based treatment modality relying on the generation of targeted cavitation bubble clouds, which mechanically fractionate tissue. The purpose of the current study was to investigate the in vivo feasibility, including dosage requirements and safety, of generating well-confined destructive lesions within the porcine brain utilizing histotripsy technology., Methods: Following a craniectomy to open an acoustic window to the brain, histotripsy pulses were delivered to generate lesions in the porcine cortex. Large lesions with a major dimension of up to 1 cm were generated to demonstrate the efficacy of histotripsy lesioning in the brain. Gyrus-confined lesions were generated at different applied dosages and under ultrasound imaging guidance to ensure that they were accurately targeted and contained within individual gyri. Clinical evaluation as well as MRI and histological outcomes were assessed in the acute (≤ 6 hours) and subacute (≤ 72 hours) phases of recovery., Results: Histotripsy was able to generate lesions with a major dimension of up to 1 cm in the cortex. Histotripsy lesions were seen to be well demarcated with sharp boundaries between treated and untreated tissues, with histological evidence of injuries extending ≤ 200 µm from their boundaries in all cases. In animals with lesions confined to the gyrus, no major hemorrhage or other complications resulting from treatment were observed. At 72 hours, MRI revealed minimal to no edema and no radiographic evidence of inflammatory changes in the perilesional area. Histological evaluation revealed the histotripsy lesions to be similar to subacute infarcts., Conclusions: Histotripsy can be used to generate sharply defined lesions of arbitrary shapes and sizes in the swine cortex. Lesions confined to within the gyri did not lead to significant hemorrhage or edema responses at the treatment site in the acute or subacute time intervals.

Objective: Data on long-term functional recovery (LFR) following severe brain injury are essential for counseling of surrogates and for appropriate timing of outcome assessment in clinical trials. Delayed functional recovery (DFR) beyond 3-6 months is well documented following severe traumatic brain injury (sTBI), but there are limited data on DFR following severe cerebrovascular brain injury. The objective of this study was to assess LFR and DFR in patients with sTBI and severe stroke dependent on tracheostomy and tube feeding at the time of discharge from the intensive care unit (ICU)., Methods: The authors identified patients entered into their tracheostomy database 2008-2013 with sTBI and severe stroke, encompassing SAH, intracerebral hemorrhage (ICH), and acute ischemic stroke (AIS). Eligibility criteria included disease-specific indicators of severity, Glasgow Coma Scale score < 9 at time of tracheostomy, and need for tracheostomy and tube feeding at ICU discharge. Assessment was at 1-3 months, 6-12 months, 12-24 months, and 24-36 months after initial injury for presence of tracheostomy, ability to walk, and ability to perform basic activities of daily living (B-ADLs). Long-term functional recovery (LFR) was defined as recovery of the ability to walk or perform B-ADLs by the 24- to 36-month follow-up. Delayed functional recovery (DFR) was defined as progression in functional milestones between any 2 time points beyond the 1- to 3-month follow-up., Results: A total of 129 patients met the eligibility criteria. Functional outcomes were available for 129 (100%), 97 (75%), 83 (64%), and 80 (62%) patients, respectively, from assessments at 1-3, 6-12, 12-24 and 24-36 months; 33 (26%) died by 24-36 months. Fifty-nine (46%) regained the ability to walk and 48 (37%) performed B-ADLs at some point during their recovery. Among survivors who had not achieved the respective milestone at 1-3 months, 29/58 (50%) were able to walk and 28/74 (38%) performed B-ADLs at 6-12 months. Among survivors who had not achieved the respective milestone at 6-12 months, 5/16 (31%) were able to walk and 13/30 (43%) performed B-ADLs at 12-24 months. There was no significant difference in rates of LFR or DFR between patients with sTBI and those with severe stroke., Conclusions: Among patients with severe brain injury requiring tracheostomy and tube feeding at ICU discharge, 46% regained the ability to walk and 37% performed B-ADLs 2-3 years after injury. DFR beyond 1-3 and 6-12 months was seen in over 30% of survivors, with no significant difference between sTBI and severe stroke.