Molecular diagnosis of diffuse glioma using a chip-based digital PCR system to analyze IDH, TERT, and H3 mutations in the cerebrospinal fluid.

PURPOSE: Conventional genetic analyzers require surgically obtained tumor tissues to confirm the molecular diagnosis of diffuse glioma. Recent technical breakthroughs have enabled increased utilization of cell-free tumor DNA (ctDNA) in body fluids as a reliable resource for molecular diagnosis in various cancers. Here, we tested the application of a chip-based digital PCR system for the less invasive diagnosis (i.e., liquid biopsy) of diffuse glioma using the cerebrospinal fluid (CSF). METHODS: CSF samples from 34 patients with diffuse glioma were collected from the surgical field during craniotomy. Preoperative lumbar CSF collection was also performed in 11 patients. Extracted ctDNA was used to analyze diagnostic point mutations in IDH1 R132H, TERT promoter (C228T and C250T), and H3F3A (K27M) on the QuantStudio® 3D Digital PCR System. These results were compared with their corresponding tumor DNA samples. RESULTS: We detected either of the diagnostic mutations in tumor DNA samples from 28 of 34 patients. Among them, we achieved precise molecular diagnoses using intracranial CSF in 20 (71%). Univariate analyses revealed that the World Health Organization (WHO) grade (p = 0.0034), radiographic enhancement (p = 0.0006), and Mib1 index (p = 0.01) were significant predictors of precise CSF-based molecular diagnosis. We precisely diagnosed WHO grade III or IV diffuse gliomas using lumbar CSF obtained from 6 (87%) of 7 patients with tumors harboring any mutation. CONCLUSION: We established a novel, non-invasive molecular diagnostic method using a chip-based digital PCR system targeting ctDNA derived from CSF with high sensitivity and specificity, especially for high-grade gliomas.

Volumetric study reveals the relationship between outcome and early radiographic response during bevacizumab-containing chemoradiotherapy for unresectable glioblastoma.

PURPOSE: Although we have shown the clinical benefit of bevacizumab (BEV) in the treatment of unresectable newly diagnosed glioblastomas (nd-GBM), the relationship between early radiographic response and survival outcome remains unclear. We performed a volumetric study of early radiographic responses in nd-GBM treated with BEV. METHODS: Twenty-two patients with unresectable nd-GBM treated with BEV during concurrent temozolomide radiotherapy were analyzed. An experienced neuroradiologist interpreted early responses on fluid-attenuated inversion recovery (FLAIR) and gadolinium-enhanced T1-weighted images (GdT1WI). Volumetric changes were evaluated using diffusion-weighted imaging (DWI) and GdT1WI according to the Response Assessment in Neuro-Oncology (RANO) criteria. The results were categorized into improved (complete response [CR] or partial response [PR]) or non-improved (stable disease [SD] or progressive disease [PD]) groups; outcomes were compared using Kaplan-Meier analysis. RESULTS: The volumetric GdT1WI improvement was a significant predictive factor for overall survival (OS) prolongation (p = 0.0093, median OS: 24.7 vs. 13.6 months); however, FLAIR and DWI images were not predictive. The threshold for the neuroradiologist's interpretation of improvement in GdT1WI was nearly 20% of volume reduction, which was lesser than 50%, the definition of PR applied in the RANO criteria. However, even less stringent neuroradiologist interpretation could successfully predict OS prolongation (improved vs. non-improved: p = 0.0067, median OS: 17.6 vs. 8.3 months). Significant impact of OS on the early response in volumetric GdT1WI was observed within the cut-off range of 20-50% (20%, p = 0.0315; 30%, p = 0.087; 40%, p = 0.0456). CONCLUSIONS: Early response during BEV-containing chemoradiation can be a predictive indicator of patient outcome in unresectable nd-GBM.

First-line bevacizumab contributes to survival improvement in glioblastoma patients complementary to temozolomide.

INTRODUCTION: First-line bevacizumab (BEV) is now available as a treatment option for glioblastoma patients with severe clinical conditions in Japan. However, the survival benefits remain controversial. To elucidate these potential survival benefits, we retrospectively analyzed survival in glioblastoma patients receiving BEV. METHODS: We analyzed survival in 120 patients with IDH-wild type glioblastoma treated from 2002 to 2018. Overall survival (OS) was assessed in three treatment era subgroups [pre-temozolomide (TMZ), TMZ, and TMZ-BEV], and the correlations of prognostic factors with survival were evaluated. RESULTS: An improvement in survival was observed after BEV approval (median OS in the pre-TMZ, TMZ, and TMZ-BEV eras: 14.6, 14.9, and 22.1 months, respectively). A Cox proportional hazards model identified extent of resection and MGMT methylation status as significant prognostic factors in the TMZ era; however, these factors were not significant in the TMZ-BEV era. In subgroup analyses, patients with MGMT methylation had improved OS after TMZ introduction (pre-TMZ vs. TMZ, 18.5 vs. 28.1 months; P = 0.13), and those without MGMT methylation had significantly increased OS after BEV approval (TMZ vs. TMZ-BEV, 12.2 vs. 16.7 months; P = 0.04). CONCLUSIONS: Our findings imply that optional first-line administration of BEV can overcome the impact of conventional risk factors and prolong survival complementary to TMZ. The patient subgroups benefitting from TMZ and BEV did not seem to overlap, and stratification based on risk factors, including MGMT methylation status, might be effective for selecting patients in whom BEV should be preferentially used as a first-line therapy.

Usefulness of non-slip element percutaneous transluminal angioplasty scoring balloons in treating severe calcified lesions of the carotid artery for carotid artery stenting: A case report.

Background: Treatment of calcified lesions with conventional angioplasty balloons can be difficult due to insufficient lumen expansion, high dissection rates, and repeated revascularization. We report a case in which a scoring balloon was used in lesions resistant to angioplasty with a semi-compliant balloon. Case Description: A 72-year-old man presented with severe stenosis and a highly calcified lesion in the right cervical internal carotid artery. Right carotid artery stenting (CAS) was planned to prevent future ischemic stroke events. Conventional semi-compliant balloon angioplasty was unsuccessful. Three inflations of a non-slip element (NSE) percutaneous transluminal angioplasty (PTA) scoring balloon (Nipro, Osaka, Japan) successfully achieved CAS without complications. Conclusion: This is the first report to describe the use of this scoring balloon in de novo carotid artery disease. NSE PTA scoring balloon catheters can be a useful option for refractory, highly calcified stenosis.

Spinal magnetic resonance imaging artifacts in lumboperitoneal shunt surgery using adjustable valve implantation on the paravertebral spinal muscles.

BACKGROUND: Adjustable shunt valves that have been developed for managing hydrocephalus rely on intrinsically magnetic components ; thus, artifacts with these valves on magnetic resonance imaging (MRI) are inevitable. No studies on valve-induced artifacts in lumboperitoneal shunt (LPS) surgery have been published. Therefore, this study aimed to evaluate valve-induced artifacts in LPS. METHODS: We retrospectively reviewed all MRIs obtained between January 2023 and June 2023 in patients with an implanted Codman CERTAS Plus adjustable shunt valve (Integra Life Sciences, Princeton, New Jersey, USA). The valve was placed <1 cm subcutaneously on the paravertebral spinal muscle of the back, with its long axis perpendicular to the body axis. The scans were performed using a Toshiba Medical Systems 1.5 Tesla scanner. The in-plane artifact sizes were assessed as the maximum distance of the artifact from the expected region of the back. RESULTS: All spinal structures or spinal cords can be recognized, even with valve-induced artifacts. The median maximum valve-induced artifact distance on T1-weighted axial imaging was 25.63 mm (mean, 25.98 mm ; range, 22.24-30.94 mm). The median maximum valve-induced artifact distance on T2-weighted axial imaging was 25.56 mm (mean, 26.27 mm ; range, 21.83-29.53 mm). CONCLUSION: LPS surgery with adjustable valve implantation on paravertebral muscles did not cause valve-induced artifacts in the spine and spinal cord. We considered that LPS could simplify the postoperative care of these patients. J. Med. Invest. 71 : 154-157, February, 2024.

Delayed Diagnosis of Spinal Dural Arteriovenous Fistula: A Case Report and Scoping Review.

Spinal dural arteriovenous fistula (SDAVF) is among the most common arterial shunt diseases typically found in middle aged or older men. Herein, we aimed to clarify the reasons for misdiagnoses and delayed diagnoses of SDAVF, determine how these affect prognoses, and establish how they can be prevented. We conducted a PubMed/MEDLINE literature search using "spinal dural arteriovenous fistula", "delayed diagnosis", "late diagnosis", and "misdiagnosis" terms. We identified 18 articles, including 965 SDAVF cases. Patients were predominantly males (71.8-100.0%) (mean age: 53.5-71.0 years). Misdiagnoses rates varied (17.5-100.0%) and encompassed many conditions. The mean time between early manifestations and confirmed diagnosis was approximately 10-15 months and from the first radiologic image revealing dural arteriovenous fistula (DAVF) features to diagnosis was 9.2-20.7 months. Posttreatment outcomes showed a significant improvement in motor functions, gait, and micturition, particularly in patients exhibiting preoperative symptoms over a short period. SDAVF is frequently misdiagnosed or subject to delayed diagnosis, causing poor clinical outcomes. SDAVF symptoms including progressive lower-limb weakness, paresthesia, and vesicorectal dysfunction are indications for spinal magnetic resonance imaging with subsequent spinal angiography, wherein DAVF is evidenced by extensive T2 hyperintensity and flow-void abnormalities. We reported a representative case with delayed diagnosis.

Distinguishing Cerebral Infarction With Neck Pain and Hemiparesis From Cervical Spinal Epidural Hematoma Without MRI: A Case Report.

In patients presenting neck pain and hemiparesis, differentiation between cerebral infarction and cervical spinal epidural hematoma is vital yet challenging, particularly when magnetic resonance imaging (MRI) is not feasible. A 59-year-old woman presented with a sudden onset of left-sided hemiparesis and neck pain. MRI was contraindicated because the patient underwent embolization in childhood. Head computed tomography (CT) revealed no evidence of hemorrhage or early ischemic signs. Cervical CT revealed no evidence of hematoma within the spinal canal. Myelography and CT myelography revealed no significant cervical spine abnormalities. The diagnosis was cerebral infarction. Cervical spine MRI is the gold standard examination for diagnosing cervical spinal epidural hematoma, but cervical spine CT, myelography, and CT myelography may be useful when MRI is contraindicated.

Hands-on neuroendovascular practice for nonselective undergraduate medical students increases interest and aspirations in pursuing neurosurgery as a specialization.

Background: The number of medical students aspiring to become neurosurgeons has decreased worldwide, mainly due to poor work-life balance among neurosurgeons; therefore, recruiting students for neurosurgery is essential to ensure the availability and appropriate quality of neurosurgical treatment. This study aimed to evaluate the efficacy of hands-on neuroendovascular practice for nonselective undergraduate medical students to determine whether this increases their interest in neurosurgery and contributes to their aspirations of becoming neurosurgeons. Methods: Hands-on neuroendovascular practice for mechanical thrombectomy was performed by undergraduate 5th-year medical students during their 2-week clinical rotation in the Department of neurosurgery at our university hospital between April 2021 and March 2023. After the neurosurgery practice, a questionnaire about their understanding of neurosurgery and aspirations for this specialization before and after the practice was anonymously completed by all students. Results: Overall, 153 students completed the questionnaire. Of these, 140 (91.5 %) showed increased interest in neurosurgery after participating in the hands-on practice. Through this practice, the number of students who considered neurosurgery as their first choice or one of their specialty choices increased from 8 (5.2%) to 12 (7.8%) (P = 0.3534) and from 19 (12.4%) to 52 (34.0%) (P < 0.0001), respectively. Furthermore, the number of students with no aspiration to become neurosurgeons decreased from 95 (62.1%) to 43 (28.1%) (P < 0.0001). Conclusion: Hands-on neuroendovascular practice for nonselective undergraduate medical students effectively increased their interest in neurosurgery specialization and their desire to become neurosurgeons. Therefore, this practice can help recruit medical students for neurosurgery specialization.

Surgical Treatment of Vertebral Compression Fracture in a Patient with Idiopathic Normal Pressure Hydrocephalus.

Idiopathic normal pressure hydrocephalus (iNPH) with gait disturbance can be effectively treated with a cerebrospinal fluid shunt. Furthermore, balloon kyphoplasty (BKP) is a successful minimally invasive treatment for osteoporotic vertebral compression fractures (VCFs). This case report presents the surgical management of an elderly patient with iNPH who presented after a VCF due to a fall. A 77-year-old woman who had been experiencing progressive gait disturbance for five years reported experiencing back pain one month after a fall. Imaging revealed a recent L1 VCF that did not compromise the spinal canal. Furthermore, the Mini-Mental State Examination results and the timed up-and-go test were 20 points and 17.96 seconds, respectively. Magnetic resonance imaging revealed ventriculomegaly with an Evans' index of 0.35. Her symptoms improved temporarily after a tap test, and she was diagnosed with probable iNPH. BKP was performed for VCFs, followed by the lumboperitoneal (LP) shunt placement for iNPH one month later. Following the operation, her symptoms improved without complications. After one month of performing BKP, an LP shunt would be placed to prevent shunt complications, such as infection and catheter-related neurological symptoms. Screening for iNPH in the elderly who present after VCFs due to a fall may identify iNPH patients who may benefit more from surgical treatments.

Fact-Finding Survey of Treatment of Traumatic Brain Injury in Japan: Standardization of Care and Collaboration Between Neurosurgery and Emergency Departments.

BACKGROUND: Standardization of seamless treatment from prehospital injury care to initial injury and specialized care through collaboration among departments have been promoted in Japan since 2000. This survey was conducted to examine the current status of the system for treatment of traumatic brain injury (TBI) in Japan. METHODS: In February 2022, questionnaires on the treatment system and TBI care were sent to 869 facilities that participated in a training program held by the Japan Neurosurgical Society. Responses were received from 480 facilities (55.2%). These responses were compared with those in a similar survey performed in 2008. RESULTS: Among the responding facilities, 39.4% had neurosurgeons in emergency departments. Initial care for TBI was the responsibility of the neurosurgery department in 42.3% of the facilities, the emergency department in 26.0%, and jointly between these departments in 29.6%; and neurocritical care was managed by the neurosurgery department in 81.9%, the emergency department in 5.2%, and jointly in 12.1%. For patients with acute-phase TBI, intracranial pressure monitoring was performed in 72.1%. Active normothermia was performed in 86.0%, and decompressive craniectomy in 99.4%, as required. There was compliance with guidelines for treatment and management of TBI in 93.3%. CONCLUSIONS: Comparison with the 2008 results suggested role-sharing between 2 departments in TBI treatment is increasing. TBI treatment compliance with the guidelines was high. In-hospital mortality of Japanese patients with TBI has decreased since 2000. This may be due to the progress with standardization of TBI treatment and collaboration among departments in compliance with guidelines.

Rare complication of lumboperitoneal shunt with distal catheter migration into the inguinal hernia sac in two adults: A case report.

Background: Despite the proven benefits of lumboperitoneal shunt (LPS) for idiopathic normal-pressure hydrocephalus, complications such as catheter migration remain a problem. Inguinal complications of the distal catheter are rare in adults, and their management is uncertain. Herein, we present two cases of distal catheter migration into the inguinal hernia sac after LPS in adults and recommend their management. Case Description: An 86-year-old man presented with inguinal swelling. In another 82-year-old man who did not show any improvement after LPS, shunt angiography revealed LPS dysfunction due to lumbar catheter occlusion and distal LPS catheter in the right inguinal hernia sac, and lumbar catheter reconstruction was performed. Both patients did not have any symptoms, except inguinal swelling, and were followed up. After 2 weeks and 4 days, the distal catheter moved into the peritoneal cavity. Conclusion: Inguinal complications due to the migration of the distal catheter into the inguinal hernia sac are rare in LPS because frequent movements of the distal catheter due to trunk rotation dislodge it from the inguinal hernia sac for a short period. Urgent surgery was not recommended because the catheter was moved in a short period and the patients did not wish to undergo hernia repair.

Intermediate nerve neuralgia developed during hemifacial spasm follow-up: illustrative case.

BACKGROUND: Intermediate nerve neuralgia (INN) is a rare condition believed to be caused by vascular compression, with external auditory canal pain as the chief symptom. The authors reported a rare case of a 78-year-old woman who developed INN during follow-up for hemifacial spasm (HFS). OBSERVATIONS: The patient had been receiving Botox treatment for right HFS for 20 years when she developed paroxysmal electric shock pain in the right external auditory canal and tinnitus induced by opening her mouth. A three-dimensional magnetic resonance fusion image showed the cisternal portion of the facial-vestibulocochlear nerve complex to be compressed by the meatal loop of the anterior inferior cerebellar artery (AICA), which was pressed against by the posterior inferior cerebellar artery. The authors diagnosed INN, and microvascular decompression (MVD) was performed. Surgical findings were consistent with preoperative neuroimaging. In addition, the proximal portion of the meatal loop of the AICA had passed between the facial and vestibulocochlear nerves, compressing both. The AICA was moved and the nerve completely decompressed. All symptoms improved immediately following surgery. LESSONS: When INN occurs during HFS follow-up, aggressive MVD should be considered based on detailed neuroimaging. This treatment is a very effective single-stage cure for INN, HFS, and vestibulocochlear symptoms.

Recanalization for straight sinus thrombosis through combined mechanical thrombectomy: A case report.

Background: Systemic anticoagulation has been the standard treatment for cerebral venous sinus thrombosis (CVT). Although endovascular treatments, including mechanical thrombectomy (MT), have been reported to be effective for CVT, no clear evidence has been established. Case Description: A 51-year-old woman who had been administered oral contraceptive pills was transferred to our hospital with altered consciousness and disorientation. Computed tomography (CT) revealed a hyperdense signal in the straight sinus (StS), and CT angiography revealed a defect in the basal vein and StS, leading to a diagnosis of StS thrombosis. Although systemic anticoagulation through unfractionated heparin was performed, her neurological condition deteriorated, and venous ischemia was observed on CT the next day. She then underwent MT. Partial recanalization was achieved with an aspiration catheter and a stent retriever. Her neurological condition improved tremendously, and venous ischemia was reversed following MT. She was discharged 3 weeks later without neurological deficits with oral anticoagulant. Conclusion: This was a relatively rare case with CVT confined to StS. Immediate combined MT for StS thrombosis can improve venous circulation, make the venous ischemia reversible, and improve patient outcomes, even if it results in partial recanalization.

Trigeminal neuropathy after tozinameran vaccination against COVID-19 in postmicrovascular decompression for trigeminal neuralgia: illustrative case.

BACKGROUND: Vaccines against coronavirus disease 2019 have a high level of efficacy and safety across all populations. However, numerous case series have been published on neurological disorders, including Bell's palsy, Guillain-Barre syndrome, transverse myelitis, and multiple sclerosis. The authors presented a case of trigeminal neuropathy after coronavirus vaccination in a patient who had undergone microvascular decompression (MVD) for trigeminal neuralgia (TN). OBSERVATIONS: A 77-year-old woman presented with acute trigeminal neuropathy after receiving a Pfizer-BioNtech vaccination (tozinameran) against severe acute respiratory syndrome coronavirus 2. The patient had undergone MVD for TN and the facial pain completely disappeared. One month later, she received the first injection of the tozinameran vaccine. Twelve hours after vaccination, she presented with numbness and pain induced by touching any place on the entire right face. No eruption was observed on her face. The serum herpes zoster virus antibodies were confirmed within the normal range. Magnetic resonance imaging revealed no abnormalities. The authors suspected a right trigeminal neuropathy after vaccination. Administration of carbamazepine and pregabalin improved TN but facial numbness persisted, especially in the mandibular division. LESSONS: The coronavirus is a possible etiology of secondary trigeminal neuropathy in the case of MVD for TN.

Unruptured aneurysm at bifurcation of super short middle cerebral artery mimicking duplicated middle cerebral artery aneurysm.

Background: Duplicated middle cerebral artery (DMCA) is a normal variation of the middle cerebral artery (MCA), and distinguishing DMCA from other arteries based only on the angiographical findings is sometimes difficult. Case Description: Preoperative angiography of a 60-year-old woman revealed two MCAs originating near the top of the right internal carotid artery and a 6-mm-sized aneurysm located between these two MCAs. The ipsilateral A1 segment of the anterior cerebral artery was not visualized due to hypoplasia. The patient was diagnosed with an unruptured aneurysm at the bifurcation between MCA and DMCA, preoperatively. However, during clipping surgery, the hypoplastic A1 segment was observed at approximately 2 mm proximal to the bifurcation of the MCA, indicating that these two MCAs were not "true" MCA and DMCA, but rather two normal MCA trunks bifurcated from the very short prebifurcation segment of M1. This difference in interpretation was due to the fact that the hypoplastic A1 was not visualized on preoperative examinations. The patient was discharged following the surgery without any neurological deficits. Conclusion: The distinction between DMCA and MCA trunks from the very short prebifurcation segment of MCA might be difficult, especially when the ipsilateral A1 segment is hypoplastic. Such an M1 with a length of 2-3 mm might be named super short M1. Thus, it is necessary to confirm the anatomy during aneurysm surgery.

A complete thrombotic large aneurysm at the nonbranching segment of the distal anterior cerebral artery mimicking a cavernous malformation: illustrative case.

BACKGROUND: Thrombotic aneurysms at the nonbranching segment of the distal anterior cerebral artery (ACA) are extremely rare and difficult to differentiate from cavernous malformations by radiographic features alone. OBSERVATIONS: Computed tomography and magnetic resonance imaging of a 30-year-old female patient with a chronic headache complaint revealed a 22-mm frontal lobe mass. The mass showed heterogeneous mixed intensity and hemosiderin deposits on magnetic resonance images. It was not visualized by conventional angiography, indicating that the mass and ACA/other vessels were not connected. The patient was preoperatively diagnosed with a cavernous malformation. However, during resection, the mass surface was white and smooth, different from a cavernous malformation. Although the mass was adherent to the pericallosal artery branch, no luminal continuity was observed. After detachment, the mass was completely resected. Pathological and immunohistochemical findings indicated a vessel wall and interior thrombus. The patient was rediagnosed with a thrombotic aneurysm at the distal ACA nonbranching segment and discharged 10 days postsurgery without neurological deficits. LESSONS: Because radiographic findings of thrombotic aneurysm and cavernous malformation are similar, mass lesions in contact with major arteries should be differentiated as thrombotic aneurysms, even when the artery lumen appears disconnected from the mass.

The development of a new, ultra-fine, and flexible neuroendoscope for intracranial observation.

Background: A neuroendoscope is a technical advance that allows surgeons to visualize certain regions of the brain that was previously inaccessible through the use of a surgical microscope. Several neuroendoscope designs have been implemented by other neurosurgeons over the past 5 years. The advantage of a neuroendoscope is the addition of a flexible and narrow tip that allows for safe entry into intracranial structures for clinical observation. However, there are some limitations to this approach. Here, we report the use of a modified angioscope as a newly developed neuroendoscope to be employed in observing intracranial structures. Methods: We report the use of an angioscope that is 1.8 mm in diameter and has both a thin and flexible tip. In this study, the angioscope was inserted into the lumen of an aspirator tube, and the tip of the device was placed at the intracranial area of intended observation area. Image findings were evaluated using an established in vivo goat brain model. Results: The angioscope was light in weight and maneuverable and could be reached and observed in the blind spot using a surgical microscope. From the cerebellopontine angle, the lower cranial nerves and trigeminal nerve could be observed, and from the cisterna magna, the floor of the fourth ventricle and the aqueduct could be seen. Conclusion: The angioscope is a useful instrument to observe intracranial locations safely and effectively even within a limited surgical field. Further modifications will be required to use the angioscope in various craniotomy procedures.

Stent retriever angioplasty for acute atherosclerotic occlusion of internal carotid artery: A case report.

Background: Despite the proven benefit of stent retriever thrombectomy for acute ischemic stroke caused by large-vessel embolic occlusion, acute revascularization in the setting of underlying intracranial, atherosclerosis-related, and emergent large-vessel occlusion remains to be a challenge. In this case report, we present a novel revascularization technique that can be used to treat acute ischemic stroke caused by suspected intracranial, atherosclerosis-related, and emergent large-vessel occlusion of the internal carotid artery (ICA). Case Description: This case report presents two patients with intracranial, atherosclerosis-related, and emergent large-vessel occlusion of the ICA: a 73-year-old man with a right-sided hemiparesis and aphasia and a 60-year-old man with altered level of consciousness. These patients were treated using the prolonged deployment and partial resheath method with a stent retriever, using the following devices: Solitaire Platinum, Trevo Trak 21, and AXS catalyst 6 for suction. On prolonged deployment of the Solitaire Platinum device, underlying focal atherosclerotic disease was noted. The device remained in place for more than 10 min, until the blood vessel was occluded. Next, the device was partially resheathed into the Trevo Trak 21 to reduce the radial force and minimize vessel injury during the pull. The partially constrained device was then retrieved under continuous aspiration at the lesion site and blood flow was successfully restored. Both patients recovered without any new deficits. Conclusion: The prolonged deployment and partial resheath method using a stent retriever may be safe and effective in the treatment of intracranial, atherosclerosis-related, and emergent large-vessel occlusion of the ICA.