Reappraisal of Microsurgical Revascularization for Anterior Circulation Ischemia in Patients with Progressive Stroke

Differences between Acute Embolic and Atherosclerotic Middle Cerebral Artery Occlusion in Multiphase Arterial Spin-labeling Imaging

Arterial spin-labeling magnetic resonance imaging (ASL-MRI) is widely used for evaluating collateral development in patients with acute ischemic stroke (AIS). This study aimed to characterize the findings of multiphase ASL-MRI between embolic and atherosclerotic large vessel occlusion (LVO) to aid in the differential diagnosis. Among 982 patients with AIS, 44 who were diagnosed with acute, symptomatic, and unilateral occlusion of the horizontal segment of the middle cerebral artery (MCA) were selected and categorized into embolic stroke (ES) and atherosclerosis (AT) groups. Using ASL-MRI (postlabeling delay [PLD] of 1.5, 2.0, and 2.5 s) at admission, the ipsilateral to contralateral ratio (ICR) of the signal intensity and its time-course increasing rate (from PLD 1.5 to 2.0 and 2.5, ΔICR) were measured and compared between the two groups. The mean ICR was significantly higher in the AT group than in the ES group (AT vs. ES: 0.49 vs. 0.27 for ICR1.5, 0.73 vs. 0.32 for ICR2.0, and 0.92 vs. 0.37 for ICR2.5). The ΔICR of PLD 1.5-2.0 (ΔICR2.0) and 2.5 (ΔICR2.5) were also significantly higher in the AT group than in the ES group (AT vs. ES: 50.9% vs. 26.3% for ΔICR2.0, and 92.6% vs. 42.9% for ΔICR2.5). Receiver operating characteristic curves showed moderate-to-strong discriminative abilities of each ASL-MRI parameter in predicting MCA occlusion etiology. In conclusion, multiphase ASL-MRI parameters may aid in differentiating intracranial LVO etiology during the acute phase. Thus, it is applicable to AIS management.

Deep learning-based video-analysis of instrument motion in microvascular anastomosis training

PURPOSE

Attaining sufficient microsurgical skills is paramount for neurosurgical trainees. Kinematic analysis of surgical instruments using video offers the potential for an objective assessment of microsurgical proficiency, thereby enhancing surgical training and patient safety. The purposes of this study were to develop a deep-learning-based automated instrument tip-detection algorithm, and to validate its performance in microvascular anastomosis training.

METHODS

An automated instrument tip-tracking algorithm was developed and trained using YOLOv2, based on clinical microsurgical videos and microvascular anastomosis practice videos. With this model, we measured motion economy (procedural time and path distance) and motion smoothness (normalized jerk index) during the task of suturing artificial blood vessels for end-to-side anastomosis. These parameters were validated using traditional criteria-based rating scales and were compared across surgeons with varying microsurgical experience (novice, intermediate, and expert). The suturing task was deconstructed into four distinct phases, and parameters within each phase were compared between novice and expert surgeons.

RESULTS

The high accuracy of the developed model was indicated by a mean Dice similarity coefficient of 0.87. Deep learning-based parameters (procedural time, path distance, and normalized jerk index) exhibited correlations with traditional criteria-based rating scales and surgeons' years of experience. Experts completed the suturing task faster than novices. The total path distance for the right (dominant) side instrument movement was shorter for experts compared to novices. However, for the left (non-dominant) side, differences between the two groups were observed only in specific phases. The normalized jerk index for both the right and left sides was significantly lower in the expert than in the novice groups, and receiver operating characteristic analysis showed strong discriminative ability.

CONCLUSION

The deep learning-based kinematic analytic approach for surgical instruments proves beneficial in assessing performance in microvascular anastomosis. Moreover, this methodology can be adapted for use in clinical settings.

Rescue Extracranial-Intracranial Bypass for Ischemic Stroke Secondary to Progressive Human Immunodeficiency Virus-Associated Vasculopathy

BACKGROUND

 Human immunodeficiency virus (HIV) associated vasculopathy can cause ischemic cerebral stroke; however, there is limited evidence on optimal management. Herein, we report a case of acute ischemic stroke due to progressive internal carotid artery (ICA) stenosis in an HIV-positive patient. Superficial temporal artery to middle cerebral artery (STA-MCA) bypass, in addition to the best medical treatments, prevented stroke progression.

CLINICAL DESCRIPTION

 A 39-year-old man with HIV infection presented with a sudden onset of aphasia and right hemiparesis. Magnetic resonance imaging revealed an ischemic lesion in the left basal ganglia and concentric thickening of the vessel wall in the terminal portion of the bilateral ICAs. Despite maximal medical treatments for HIV-associated vasculopathy and possible opportunistic infections, bilateral ICA stenoses progressed, leading to a second hemodynamic stroke event. Because tissue plasminogen activator treatment failed, we performed STA-MCA bypass. A significant improvement in neurologic symptoms and cerebral blood flow was observed after surgery. No further stroke events occurred during the continuation of medical treatments.

CONCLUSION

 This is the first case of STA-MCA bypass performed in a patient with recurrent ischemic stroke caused by HIV-associated vasculopathy. Although further evidence is needed, such treatment options can shed new light on the management of progressive HIV-associated vasculopathy, which is refractory to maximal medical treatment.

2-1-2 Stroke microsurgical thrombectomy technique as a tertiary/salvage treatment option

BACKGROUND

Microsurgical thrombectomy (MST) has been used for many years in few stroke cases without any prospective randomized study, nor detailed systemized technique description. As many centers worldwide are recruited for stroke thrombectomy availability, MST might increase in the near future either as a tertiary or salvage treatment option. A straightforward surgical plan is mandatory empowering a safe, efficient, and rapid neurosurgical operation, so our aim is to describe the 2-1-2 microsurgical technique.

METHODS

Three patients presented at emergency department with large stroke not suitable to venous thrombolysis and/or mechanical thrombectomy due to late arrival time and endovascular suite technical problems. They were referred to 2-1-2 MST after imaging showed brain collaterals on head angio-CT scan and ASPECTS greater than 6 points. The procedure comprised 2 insulin needle punctures in the target artery, 1mm micro-scissor transverse arteriotomy, milk thrombus removal and 2 simple sutures micro stitches. Sixty days clinical follow-up and brain imaging control provided data results.

RESULTS

All patients treated with 2-1-2 MST technique had complete thrombus removal by precise surgical maneuvers avoiding surgeons unplanned and insecure movements to reduced operation time. Head angio-CT scan evidenced complete cerebrovascular circulation re-flow with clinical improvements in 60 days follow-up without complications or hospital readmissions.

CONCLUSIONS

2-1-2 MST technique can be rapidly and efficaciously performed in a systemized manner offering a tertiary or salvage technique for acute stroke treatment. Specific microsurgical training is mandatory to accomplish this treatment and larger studies are necessary to confirm our hypothesis.

Tissue Acceleration as a Novel Metric for Surgical Performance During Carotid Endarterectomy

BACKGROUND AND OBJECTIVES

Gentle tissue handling to avoid excessive motion of affected fragile vessels during surgical dissection is essential for both surgeon proficiency and patient safety during carotid endarterectomy (CEA). However, a void remains in the quantification of these aspects during surgery. The video-based measurement of tissue acceleration is presented as a novel metric for the objective assessment of surgical performance. This study aimed to evaluate whether such metrics correlate with both surgeons' skill proficiency and adverse events during CEA.

METHODS

In a retrospective study including 117 patients who underwent CEA, acceleration of the carotid artery was measured during exposure through a video-based analysis. Tissue acceleration values and threshold violation error frequencies were analyzed and compared among the surgeon groups with different surgical experience (3 groups: novice , intermediate , and expert ). Multiple patient-related variables, surgeon groups, and video-based surgical performance parameters were compared between the patients with and without adverse events during CEA.

RESULTS

Eleven patients (9.4%) experienced adverse events after CEA, and the rate of adverse events significantly correlated with the surgeon group. The mean maximum tissue acceleration and number of errors during surgical tasks significantly decreased from novice, to intermediate, to expert surgeons, and stepwise discriminant analysis showed that the combined use of surgical performance factors could accurately discriminate between surgeon groups. The multivariate logistic regression analysis revealed that the number of errors and vulnerable carotid plaques were associated with adverse events.

CONCLUSION

Tissue acceleration profiles can be a novel metric for the objective assessment of surgical performance and the prediction of adverse events during surgery. Thus, this concept can be introduced into futuristic computer-aided surgeries for both surgical education and patient safety.

Clinical Analysis of Microvascular Reconstruction Combined With Decompressive Craniectomy in Patients With Malignant Middle Cerebral Artery Infarctions

PURPOSE

This study aimed to evaluate the safety and efficacy of microvascular reconstruction combined with decompressive craniectomy (DHC) in patients with malignant middle cerebral artery infarctions (MMCA).

METHODS

We searched for patients with MMCA and aged＜60 years old, postoperative survival of more than 3 months, consistent with decompression of bone flap removal. Patients were divided into experimental group and control group according to whether they underwent emergency vascular revascularization within 5 days after onset of ischemic stroke.

RESULTS

A total of sixpatients were included in the treatment group and 12 patients in the control group. The National Institutes of Health Stroke Scale (NIHSS) score of the treatment group was lower than that of the control group seven days after operation, but the difference was not statistically significant; 3 months after surgery, modified ranking scale (mRs) score in the treatment group was lower than that in the control group, the difference was statistically significant (P = 0.002); mRs scores of the treatment group 3 months after surgery were significantly different from those before surgery (P < 0.05), but no such difference was found in the control group.

CONCLUSION

Compared with decompressive craniectomy, open surgical revascularization can improve early cerebral perfusion in MMCA patients, and neurological recovery is better at 3 months after operation. By ensuring that surgeons are properly trained and hospitals are equipped, open surgical revascularization can be a treatment option for patients with MMCA.

Long-term outcomes and quantitative radiologic analysis of extracranial-intracranial bypass for hemodynamically compromised chronic large artery occlusive disease

This study aimed to demonstrate the effectiveness of nonemergent extracranial-to-intracranial bypass (EIB) in symptomatic chronic large artery atherosclerotic stenosis or occlusive disease (LAA) through quantitative analysis of computed tomography perfusion (CTP) parameters using RAPID software. We retrospectively analyzed 86 patients who underwent nonemergent EIB due to symptomatic chronic LAA. CTP data obtained preoperatively, immediately postoperatively (PostOp0), and 6 months postoperatively (PostOp6M) after EIB were quantitatively analyzed through RAPID software, and their association with intraoperative bypass flow (BF) was assessed. The clinical outcomes, including neurologic state, incidence of recurrent infarction and complications, were also analyzed. The time-to-maximum (Tmax) > 8 s, > 6 s and > 4 s volumes decreased significantly at PostOp0 and up through PostOp6M (preoperative, 5, 51, and 223 ml (median), respectively; PostOp0, 0, 20.25, and 143 ml, respectively; PostOp6M, 0, 7.5, and 148.5 ml, respectively; p < 0.001, p < 0.001, and p < 0.001, respectively). The postoperative improvement in the Tmax > 6 s and > 4 s volumes was significantly correlated with the BF at PostOp0 and PostOp6M (PostOp0, r = 0.367 (p = 0.001) and r = 0.275 (p = 0.015), respectively; PostOp6M r = 0.511 (p < 0.001) and r = 0.391 (p = 0.001), respectively). The incidence of recurrent cerebral infarction was 4.7%, and there were no major complications that produced permanent neurological impairment. Nonemergent EIB under strict operation indications can be a feasible treatment for symptomatic, hemodynamically compromised LAA patients.

Quantitative radiological analysis and clinical outcomes of urgent EC-IC bypass for hemodynamic compromised patients with acute ischemic stroke

This study aimed to demonstrate the effectiveness of urgent extracranial-to-intracranial bypass (EIB) in acute ischemic stroke (AIS) through quantitative analysis of computed tomography perfusion (CTP) results using RAPID software. We retrospectively analyzed 41 patients who underwent urgent EIB for AIS under strict operation criteria. The quantitative data from CTP images were reconstructed to analyze changes in pre- and postoperative perfusion status in terms of objective numerical values using RAPID software. Short- and long-term clinical outcomes, including complications and neurological status, were also analyzed. Postoperatively, the volume of time-to-max (Tmax) > 6 s decreased significantly; it continued to improve significantly until 6 months postoperatively (preoperative, 78 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 7 ml; p = 0.000). Ischemic core-penumbra mismatch volumes were also significantly improved until 6 months postoperatively (preoperative, 72 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 5 ml; p = 0.000). In addition, the patients' neurological condition improved significantly (p < 0.001). Only one patient (2.3%) showed progression of infarction. Urgent EIB using strict indications can be a feasible treatment for IAT-ineligible patients with AIS due to large vessel occlusion or stenosis.

Emergent microsurgical intervention for acute stroke after mechanical thrombectomy failure: a prospective study

Background

Despite all the gains that have been achieved with endovascular mechanical thrombectomy revascularization and intravenous thrombolysis logistics since 2015, there is still a subgroup of patients with salvageable brain tissue for whom persistent emergent large vessel occlusion portends a catastrophic outcome.

Objective

To test the safety and efficacy of emergent microsurgical intervention in patients with acute ischemic stroke and symptomatic middle cerebral artery occlusion after failure of mechanical thrombectomy.

Methods

A prospective two-center cohort study was conducted. Patients with acute ischemic stroke and middle cerebral artery occlusion for whom recanalization failed at center 1 were randomly allocated to the microsurgical intervention group (MSIG) or control group 1 (CG1). All similar patients at center 2 were included in the control group 2 (CG2) with no surgical intervention. Microsurgical embolectomy and/or extracranial–intracranial bypass was performed in all MSIG patients at center 1.

Results

A total of 47 patients were enrolled in the study: 22 at center 1 (12 allocated to the MSIG and 10 to the CG1) and 25 patients at center 2 (CG2). MSIG group patients showed a better clinical outcome on day 90 after the stroke, where a modified Rankin Scale score of 0–2 was reached in 7 (58.3%) of 12 patients compared with 1/10 (10.0%) patients in the CG1 and 3/12 (12.0%) in the CG2.

Conclusions

This study demonstrated the potential for existing microsurgical techniques to provide good outcomes in 58% of microsurgically treated patients as a third-tier option.

Microsurgical Embolectomy in the Current Era of Pharmacological and Mechanical (Endovascular) Thrombolysis-A Reappraisal

Introduction

Microsurgical embolectomy though is the oldest known recanalization technique is being dismissed in favor of the latest mechanical endovascular techniques for the management of acute large vessel occlusion.

Aim and Objective

We aim to highlight the role of microsurgical embolectomy in the current era of pharmacological and mechanical (endovascular) thrombolysis.

Methods

An outline of the microsurgical embolectomy technique is described along with its current indications, advantages, and disadvantages.

Results

It carries higher complete (TICI 3) revascularization rates with lower risk of distal embolic events especially in cases with high clot burdens; but is more labor-intensive and has longer reperfusion time in comparison to endovascular methods along with the requirement of highly skilled neurovascular surgeons to perform it quickly.

Conclusion

Microsurgical embolectomy is an important indispensable recanalization technique in the armamentarium of vascular neurosurgeons.

Efficacy and Safety of Timely Urgent Superficial Temporal Artery-to-Middle Cerebral Artery Bypass Surgery in Patients with Acute Ischemic Stroke: A Single-Institutional Prospective Study and a Pooled Analysis

BACKGROUND

Clinical outcome in patients with acute ischemic stroke (AIS) caused by large vessel occlusion (LVO) is not satisfactory if reperfusion treatment fails or is not tried.

AIMS

We aimed to assess the efficacy and safety of urgent superficial temporal-to-middle cerebral artery (STA-MCA) bypass surgery in selected patients.

METHODS

Patients who were diagnosed with LVO-induced AIS in the anterior circulation but had a failed intra-arterial thrombectomy (IAT) or were not tried due to IAT contraindications were prospectively enrolled. Timely urgent STA-MCA bypass surgery was performed if they showed perfusion-diffusion mismatch or symptom-diffusion mismatch in the acute phase of disease. Clinical and radiological data of these patients were assessed to demonstrate the safety and efficacy of urgent bypass procedures. A pooled analysis of published data on urgent bypass surgery in acute stroke patients was conducted and analyzed.

RESULTS

In 18 patients who underwent timely bypass, the National Institutes of Health Stroke Scale (NIHSS) score improved from 12.11 ± 4.84 to 9.89 ± 6.52, 1 week after surgery. Three-month and long-term (9.72 ± 5.00 months) favorable outcomes (modified Rankin Scale [mRS] scores 0-2) were achieved in 50 and 75% of the patients, respectively. The pooled analysis (117 patients from 10 articles, including ours) identified favorable mRS scores in 71.79% patients at 3 months. A significant NIHSS score improvement from 11.51 ± 4.89 to 7.59 ± 5.50 was observed after surgery with significance. Major complications occurred in 3 patients (2.6%, 3/117) without mortality.

CONCLUSIONS

Urgent STA-MCA bypass surgery can be regarded as a safe optional treatment to prevent cerebral infarct expansion and to improve clinical and radiological outcomes in highly selected patients.

Flow-augmentation bypass in the treatment of acute ischemic stroke

INTRODUCTION

Results of two randomized trials did not show benefit of revascularization with extracranial-intracranial (EC-IC) flow augmentation bypass in patients with symptomatic occlusion of internal carotid artery (ICA). However, patients with acute stroke were not included in these studies. Herein, we systematically analyze and discuss the literature about flow augmentation bypass for treatment of acute ischemic stroke.

EVIDENCE ACQUISITION

This systematic review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. MEDLINE, Web of Science and EMBASE were independently searched by two reviewers for published series to identify literature relating to EC-IC bypass in the surgical management of acute ischemic stroke up to June 2020. Studies were categorized according to their level of evidence.

EVIDENCE SYNTHESIS

Nineteen studies met the inclusion criteria for the systematic literature review, including 16 level IV studies (ten case series and six6 case reports) and three level III studies (retrospective cohort case-control studies). Occurrence of fatal or non-fatal ischemic or hemorrhagic postoperative stroke, as well as clinical functional outcome at follow-up were considered as primary and secondary endpoints, respectively.

CONCLUSIONS

The literature about flow augmentation bypass for treatment of acute ischemic stroke is scarce and heterogenous, with only 19 studies. The results of the present systematic review encourage further study to explore and validate the use of EC-IC bypass in the treatment of anterior circulation acute ischemic stroke in highly selected patients (symptomatic and with persistent penumbra despite best medical/endovascular treatment).

Microsurgical Findings of Pial Arterial Feeders in Intracranial Dural Arteriovenous Fistulae: A Case Series

BACKGROUND

Pial arterial feeders in an intracranial dural arteriovenous fistula (dAVF) are risk factors for both ischemic and hemorrhagic complications during endovascular embolization. Microsurgery in dAVF with pial arterial feeders has rarely been reported.

OBJECTIVE

To assess our original experience with microsurgery for dAVF with pial arterial feeders by investigating surgical findings and outcomes.

METHODS

In 40 patients with intracranial dAVF who underwent microsurgery, we found 8 patients who had pial arterial feeders. A retrospective review was conducted.

RESULTS

The locations of the dAVFs were as follows: tentorium, 2 patients; Galenic system, 1; straight sinus, 1; torcula, 1; transverse sinus, 1; ethmoid, 1; and convexity, 1. Preoperative angiography revealed that the pial arterial feeders originated from the middle cerebral artery in 2 patients, the anterior cerebral artery in 1, the posterior cerebral artery in 2, and the posterior medial choroidal artery in 1. Of note, in 2 patients (6.7%), feeders from the superior cerebellar artery were determined to be angiographically occult during preoperative examination and were detected through careful intraoperative observation and arachnoid dissection. In 5 cases, the additional obliteration of the pial arterial feeders and/or more distal cortical venous drainers after the simple disconnection of proximal cortical drainers was necessary to cure the dAVF. Finally, all shunts were cured with only 1 minor complication.

CONCLUSION

Although microsurgical results were acceptable, the surgeon should be aware of the presence of pial arterial feeders even after the simple disconnection of cortical venous drainage. Angiographically occult feeders may also exist.

Management and prognosis of acute extracranial internal carotid artery occlusion

Acute occlusion of the internal carotid artery is the underlying etiology in 4 to 15% of all ischemic strokes. The clinical presentation varies considerably ranging from asymptomatic occlusion to severe ischemic strokes. Substantial differences in the acute management of acute symptomatic internal carotid artery occlusions (ICAO) exists between centers. Thusly, we comprised a narrative review of the natural course of acute ICAO and of available treatment options [i.v. thrombolysis, endovascular thrombectomy and stenting, bypass between the superficial temporal and the middle cerebral arteries (MCA) and carotid endarterectomy (CEA)]. We found that very few randomized treatment trials have been performed in patients acute symptomatic ICAO. Most evidence stems from case series and observational studies. Especially in older studies the intracranial vessel status has rarely been considered. After revision of these studies we concluded that the mainstay of the acute management of acute symptomatic ICAO is i.v. thrombolysis when applied within the label and in combination with mechanical thrombectomy in case of intracranial large vessel occlusion. In cases without intracranial large vessel occlusion mechanical thrombectomy of acute ICAO is associated with a risk of distal embolization. More research on prognostic parameters is needed to better characterize the risk of decompensation of collateral flow and to better define the time-window of intervention. When mechanical thrombectomy fails or is not available, surgical approaches are an alternative in selected patients.

Open Microvascular Thrombectomy for Acute Intracranial Large Vessel Occlusion: Microsurgery in the Endovascular Thrombectomy Era

BACKGROUND

Open microsurgical thrombectomy for acute intracranial large vessel occlusion (LVO) has been the subject of dozens of case reports and series. However, no clear indications exist to define its role in the management of acute ischemic stroke. Our aim was to review all the available data on open microsurgical thrombectomy, for both spontaneous as well as iatrogenic intracranial vessel occlusion, in terms of indication and results.

METHODS

Of the 390 articles screened, 33 were included after full text screening.

RESULTS

A total of 232 patients were reported, of whom 208 received microsurgical thrombectomy and 24 received bypass for large vessel occlusion. Patients were divided into a historic cohort (before 2002) and a recent cohort (articles published after 2002). Patients from the historic cohort were younger: median age, 55 years (interquartile range, 34-57 years) versus 69 years (interquartile range, 63-75 years) in the recent cohort (P < 0.01). The procedure was successful more often in the recent cohort (65% of patients in the historic cohort vs. 98% of patients in the recent cohort) and more patients experienced neurologic improvement (56% of patients in the historic cohort vs. 69% in the recent cohort).

CONCLUSIONS

In the era of endovascular thrombectomy, open microsurgical techniques might still play a role in highly selected patients. The reported patients show that microsurgical thrombectomy seems efficient and effective in improving patient outcome. Ideally, a multidisciplinary approach with vascular neurosurgeons trained and skilled in microvascular techniques is recommended.

Effect of Adventitial Dissection of Superficial Temporal Artery on the Outcome of Superficial Temporal Artery-Middle Cerebral Artery Bypass in Moyamoya Disease

Superficial temporal artery-middle cerebral artery (STA-MCA) has been used for the treatment of occlusive cerebrovascular disease including moyamoya disease. The effect of STA-MCA bypass depends not only on the patency of anastomosis, but also on integrity and functional capacity of the donor artery. In the present prospective study, we investigated the effect of extensive stripping STA adventitia and fasciae on hemodynamic function in STA-MCA bypass of moyamoya disease patients. Twenty patients (n=8 in control group, n=12 in stripping group) of moyamoya disease were subjected to STA-MCA end-to-side direct anastomosis. Perfusion unit (PU) values of the cortex were measured and recorded using a Laser Doppler flowmetry (LDF) for 5 days. Computed tomography perfusion was performed to determine blood flow before and after bypass. No patient experienced significant neurologic deficits associated with neurosurgical complications. LDF demonstrated that adventitial stripping group had higher cerebral blood flow increase than control group. The adventitia stripping group tends to have higher rate of increased cerebral perfusion after bypass than non-stripping group. Furthermore, the ultrasound examination at 3 days after bypass demonstrated that the adventitial stripping group has a tendency of bigger STA and higher peak systolic velocity than control group. Our result suggests that stripping adventitia of STA improves hemodynamics of STA-MCA bypass in moyamoya disease.