First Experience of Three Neurovascular Centers With the p64MW-HPC, a Low-Profile Flow Diverter Designed for Proximal Cerebral Vessels With Antithrombotic Coating.

Background: In the last decade, flow diversion (FD) has been established as hemodynamic treatment for cerebral aneurysms arising from proximal and distal cerebral arteries. However, two significant limitations remain-the need for 0.027" microcatheters required for delivery of most flow diverting stents (FDS), and long-term dual anti-platelet therapy (DAPT) in order to prevent FDS-associated thromboembolism, at the cost of increasing the risk for hemorrhage. This study reports the experience of three neurovascular centers with the p64MW-HPC, a FDS with anti-thrombotic coating that is implantable via a 0.021" microcatheter. Materials and methods: Three neurovascular centers contributed to this retrospective analysis of patients that had been treated with the p64MW-HPC between March 2020 and March 2021. Clinical data, aneurysm characteristics, and follow-up results, including procedural and post-procedural complications, were recorded. The hemodynamic effect was assessed using the O'Kelly-Marotta Scale (OKM). Results: Thirty-two patients (22 female, mean age 57.1 years) with 33 aneurysms (27 anterior circulation and six posterior circulation) were successfully treated with the p64MW-HPC. In 30/32 patients (93.75%), aneurysmal perfusion was significantly reduced immediately post implantation. Follow-up imaging was available for 23 aneurysms. Delayed aneurysm perfusion (OKM A3: 8.7%), reduction in aneurysm size (OKM B1-3: 26.1%), or sufficient separation from the parent vessel (OKM C1-3 and D1: 65.2%) was demonstrated at the last available follow-up after a mean of 5.9 months. In two cases, device thrombosis after early discontinuation of DAPT occurred. One delayed rupture caused a caroticocavernous fistula. The complications were treated sufficiently and all patients recovered without permanent significant morbidity. Conclusion: Treatment with the p64MW-HPC is safe and feasible and achieves good early aneurysm occlusion rates in the proximal intracranial circulation, which are comparable to those of well-established FDS. Sudden interruption of DAPT in the early post-interventional phase can cause in-stent thrombosis despite the HPC surface modification. Deliverability via the 0.021" microcatheter facilitates treatment in challenging vascular anatomies.

Flow Diversion for Reconstruction of Intradural Vertebral Artery Dissecting Aneurysms Causing Subarachnoid Hemorrhage-A Retrospective Study From Four Neurovascular Centers.

Objective: Dissecting aneurysms (DAs) of the vertebrobasilar territory manifesting with subarachnoid hemorrhage (SAH) are associated with significant morbi-mortality, especially in the case of re-hemorrhage. Sufficient reconstruction of the affected vessel is paramount, in particular, if a dominant vertebral artery (VA) is impacted. Reconstructive options include stent-assisted coiling and flow diversion (FD). The latter is technically less challenging and does not require catheterization of the fragile aneurysm. Our study aims to report a multicentric experience with FD for reconstruction of DA in acute SAH. Materials and Methods: This retrospective study investigated 31 patients (age: 30-78 years, mean 55.5 years) who had suffered from SAH due to a DA of the dominant VA. The patients were treated between 2010 and 2020 in one of the following German neurovascular centers: University Hospital Leipzig, Katharinenhospital Stuttgart, BG Hospital Bergmannstrost Halle/Saale, and Heinrich-Braun-Klinikum Zwickau. Clinical history, imaging, implanted devices, and outcomes were reviewed for the study. Results: Reconstruction with flow-diverting stents was performed in all cases. The p64 was implanted in 14 patients; one of them required an additional balloon-expandable stent to reconstruct severe stenosis in the target segment. One case demanded additional liquid embolization after procedural rupture, and in one case, p64 was combined with a PED. Further 13 patients were treated exclusively with the PED. The p48MW-HPC was used in two patients, one in combination with two additional Silk Vista Baby (SVB). Moreover, one patient was treated with a single SVB, one with a SILK+. Six patients died [Glasgow Outcome Scale (GOS) 1]. Causes of death were periprocedural re-hemorrhage, thrombotic occlusion of the main pulmonary artery, and delayed parenchymal hemorrhage. The remaining three patients died in the acute-subacute phase related to the severity of the initial hemorrhage and associated comorbidities. One patient became apallic (GOS 2), whereas two patients had severe disability (GOS 3) and four had moderate disability (GOS 4). Eighteen patients showed a complete recovery (GOS 5). Conclusion: Reconstruction of VA-DA in acute SAH with flow-diverting stents is a promising approach. However, the severity of the condition is reflected by high overall morbi-mortality, even despite technically successful endovascular treatment.

Indirect Flow Diversion for Off-Centered Bifurcation Aneurysms and Distant Small-Vessel Aneurysms, a Retrospective Proof of Concept Study From Five Neurovascular Centers.

Background: Treatment of cerebral aneurysms using hemodynamic implants such as endosaccular flow disruptors and endoluminal flow diverters has gained significant momentum during recent years. The intended target zone of those devices is the immediate interface between aneurysm and parent vessel. The therapeutic success is based on the reduction of aneurysmal perfusion and the subsequent formation of a neointima along the surface of the implant. However, a subset of aneurysms-off-centered bifurcation aneurysms involving the origin of efferent branches and aneurysms arising from peripheral segments of small cerebral vessels-oftentimes cannot be treated via coiling or implanting a hemodynamic implant at the neck level for technical reasons. In those cases, indirect flow diversion-a flow diverter deployed in the main artery proximal to the parent vessel of the aneurysm-can be a viable treatment strategy, but clinical evidence is lacking in this regard. Materials and Methods: Five neurovascular centers contributed to this retrospective analysis of patients who were treated with indirect flow diversion. Clinical data, aneurysm characteristics, anti-platelet medication, and follow-up results, including procedural and post-procedural complications, were recorded. Results: Seventeen patients (mean age: 60.5 years, range: 35-77 years) with 17 target aneurysms (vertebrobasilar: n = 9) were treated with indirect flow diversion. The average distance between the flow-diverting stent and the aneurysm was 1.65 mm (range: 0.4-2.4 mm). In 15/17 patients (88.2%), perfusion of the aneurysm was reduced immediately after implantation. Follow-ups were available for 12 cases. Delayed opacification (OKM A3: 11.8%), reduction in size (OKM B1-3: 29.4%) and occlusion (D1: 47.1%) were observable at the latest investigation. Clinically relevant procedural complications and adverse events in the early phase and in the late subacute phase were not observed in any case. Conclusion: Our preliminary data suggest that indirect flow diversion is a safe, feasible, and effective approach to off-centered bifurcation aneurysms and distant small-vessel aneurysms. However, validation with larger studies, including long-term outcomes and optimized imaging, is warranted.

Automatic Registration for Navigation at the Anterior and Lateral Skull Base.

OBJECTIVE: Navigation systems create a connection between imaging data and intraoperative situs, allowing the surgeon to consistently determine the location of instruments and patient anatomy during the surgical procedure. The best results regarding the target registration error (measurement uncertainty) are normally demonstrated using fiducials. This study aimed at investigating a new registration strategy for an electromagnetic navigation device. METHODS: For evaluation of an electromagnetic navigation system and comparison of registration with screw markers and automatic registration, we are calculating the target registration error in the region of the paranasal sinuses/anterior and lateral skull base with the use of an electromagnetic navigation system and intraoperative digital volume tomography (cone-beam computed tomography). We carried out 10 registrations on a head model (total n = 150 measurements) and 10 registrations on 4 temporal bone specimens (total n = 160 measurements). RESULTS: All in all, the automatic registration was easy to perform. For the models that were used, a significant difference between an automatic registration and the registration on fiducials was evident for just a limited number of screws. Furthermore, the observed differences varied in terms of the preferential registration procedure. CONCLUSION: The automatic registration strategy seems to be an alternative to the established methods in artificial and cadaver models of intraoperative scenarios. Using intraoperative imaging, there is an option to resort to this kind of registration as needed.

Complication rates using balloon-expandable and self-expanding stents for the treatment of intracranial atherosclerotic stenoses : analysis of the INTRASTENT multicentric registry.

INTRODUCTION: Using balloon-expandable stents (BES) for treatment of intracranial stenoses, high inflation pressures and rigidity of the device are regarded as major drawbacks limiting feasibility and safety of the procedure. Self-expanding stents (SES) were developed to facilitate lesion access and to allow for less aggressive dilatation. We analyzed data of the INTRASTENT multicentric registry to assess whether self-expanding stents significantly reduced peri-interventional complication rates. METHODS: Records of intracranial stent procedures were entered consecutively into the registry. Datasets were divided into two groups according to the type of stent used. For outcome measurement, we chose three categories: TIA/minor stroke [modified Rankin score (mRS) <2], disabling stroke, and patient death. Clinical outcome was compared between BES and SES. We analyzed types of adverse events occurring in each group in addition. RESULTS: Of 409 atherosclerotic lesions, 254 were treated with BES and 155 with SES. Technical success rates were 97.6% and 98.7%, respectively. Adverse event rates were 4.9%, 3.7%, and 0.8% for TIA/nondisabling stroke, disabling stroke, and death in the BES group compared with 5.3%, 6.0%, and 4.0% in the SES group. The differences were not statistically significant. We observed more perforator strokes after use of BES, but thromboembolic events occurred more often in the SES treatment group. CONCLUSION: Data of the INTRASTENT registry do not support the hypothesis that introduction of SES lowered the overall complication rate of intracranial stent procedures. There might be an advantage using self-expanding stents in vessel segments with important perforating arteries.

In-hospital complication rates after stent treatment of 388 symptomatic intracranial stenoses: results from the INTRASTENT multicentric registry.

BACKGROUND AND PURPOSE: Stenting is increasingly used as an adjunct to medical therapy in symptomatic intracranial stenoses. High periprocedural adverse event rates are one of the limitations of endovascular treatment. Data from the INTRASTENT multicentric registry should demonstrate in-hospital complications at the current stage of clinical development of the stent procedure. METHODS: Participating centers entered the records of all their consecutive intracranial stent procedures into the database. To determine the clinical outcome in the acute phase, we distinguished transient ischemic attack/nondisabling stroke (modified Rankin Scale <2), disabling stroke, death, and intracranial hemorrhage as clinical complications and analyzed whether they were associated with patient- or stenosis-related risk factors. RESULTS: Data from 372 patients with 388 stenoses proved 4.8% disabling strokes and 2.2% deaths. Transient or minor events were detected in 5.4% of the cases. Hemorrhagic events (3.5%) occurred more frequently after treatment of middle cerebral artery stenoses (P=0.004) and were associated with significantly higher morbidity and mortality rates. Ischemic strokes by compromise of perforating branches were detected mainly in the posterior circulation. However, the overall rate of severe adverse events was not dependent from location, degree, and morphology of the stenosis or from patient's age, gender, vascular risk factors, or type of qualifying event. CONCLUSIONS: The complication rates within the registry are within the limits of previously published data. Severe adverse events were equally distributed between potential risk groups with similar rates but different types of main complications in the anterior and posterior circulation.

Brachial plexus compression caused by recurrent clavicular nonunion and space-occupying pseudoarthrosis: definitive reconstruction using free vascularized bone flap-a series of eight cases.

OBJECTIVE: In rare cases, space-occupying pseudoarthrotic clavicular nonunion causes symptomatic brachial plexus compression. The surgical treatment of clavicular pseudoarthrosis has been extensively reported in the literature. This article reports our experience of a definitive treatment strategy using free vascularized fibula flaps in cases of persistent compression of the brachial plexus by relapsing bony nonunion mass lesions. METHODS: Six men (age range, 46-59 yr) and two women (ages 48 and 52 yr) with nonunions of clavicular midshaft fractures were referred between August 2001 and March 2005 because of progressive compression of the subclavicular neurovascular bundle. All of them had displaced traumatic clavicle fractures that had been treated previously at other institutions. At least two surgical reconstructive procedures had been performed beforehand. Four patients had motor deficits owing to compressive brachial plexus lesions; all showed symptoms of combined thoracic outlet syndrome. Our surgery consisted of resection of the space-occupying clavicular pseudoarthrosis (all eight patients), external neurolysis of the brachial plexus (four patients) and reconstruction of the resulting bone defect with free vascularized fibula flap secured with plates (all eight patients). Vascularity of the bone flap was studied using three-phase bone scintigraphy. RESULTS: All patients became free of pain symptoms after surgery. Muscle strength in two of the four patients with preoperative motor deficits improved to normal within 3 months; the other two patients required 6 and 8 months, respectively. Three-phase bone scintigraphy showed adequate perfusion of the bone flaps in all patients. Postoperative bleeding at the recipient site occurred in three patients; these required revision. One patient showed an osseosubcutaneous fistula 6 months after surgery, which was treated conservatively. There was no recurrence of pseudoarthrosis or neurovascular compression at a mean follow-up period of 38.5 months. CONCLUSION: Recurrent space-occupying pseudoarthrosis of the clavicle complicated with neurovascular compression might warrant definitive reconstruction using a free vascularized bone flap.

Computed tomographically-controlled injection of botulinum toxin into the longus colli muscle in severe anterocollis.

We report on a 44-year-old man who suffered from severe anterocollis. Repeated computed tomographically controlled injections of botulinum toxin into the right longus colli muscle allowed a precise location of the needle and injection of the toxin, leading to clear improvement of symptoms.