Arteriovenous malformations of the filum terminale: clinical characteristics, angioarchitecture, and management of a rare spinal vascular pathology.

OBJECTIVE: The goal of this study was to describe clinical and neuroradiological features of arteriovenous malformations of the filum terminale (FT AVMs) and to present the authors' diagnostic and therapeutic management in this rare disease. METHODS: The presented cases were retrieved from a retrospectively collected database of all spinal vascular malformations treated between June 1992 and December 2021 at the Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital Aachen. Pretreatment and follow-up clinical and neuroradiological data were analyzed for this study. RESULTS: Data in 15 patients with FT AVM with a mean age of 60 years were included, with an overall incidence of FT AVM of 19% among all spinal AVMs in our cohort. Twelve of 15 (80%) patients were men. Nonspecific but typical clinical and MR findings of thoracolumbar congestive myelopathy were found in all patients. Spinal MR angiography, performed in 10 patients, identified in all cases the arterialized FT vein as well as a lumbar/lumbosacral location of an AV shunt. Digital subtraction angiography (DSA) showed an arterial supply solely via the FT artery in 12/15 (80%) patients and via an additional feeder from the lumbosacral region in the other 3/15 (20%) patients. All patients were treated surgically. During 1-year follow-up, 2 patients presented with recurrent FT AVM due to further arterial supply from the lumbosacral region, and were treated surgically. Neurological status was improved in all patients within the 1-year follow-up, with marginal further changes during long-term follow-up. CONCLUSIONS: Congestive myelopathy is the major pathological mechanism of symptoms in these patients, with no evidence for intradural bleeding. Missing the presence of possible multiple arterial supply of FT AVM during DSA may result in misdiagnosis and/or insufficient treatment. Due to the frequently prolonged course of FT artery, resection of the FT AVM may be a favorable treatment modality in comparison with endovascular treatment. Follow-up examinations are obligatory within the first 3 years after treatment, and further MR angiography and DSA examinations are indicated if congestive myelopathy persists.

Brain invasion in meningiomas: does surgical sampling impact specimen characteristics and histology?

Brain invasion (BI) is a new criterion for atypia in meningiomas and therefore potentially impacts adjuvant treatment. However, it remains unclear whether surgical practice and specimen characteristics influence histopathological analyses and the accuracy of detecting BI. Tumor location, specimen characteristics, and rates of BI were compared in meningioma samples obtained from 2938 surgeries in different neurosurgical departments but diagnosed in a single neuropathological institute. Non-skull base tumor location was associated with CNS tissue on the microscopic slides (OR 1.45; p < .001), increasing specimen weight (OR 1.01; p < .001), and remaining tissue not subjected to neuropathological analyses (OR 2.18; p < .001) but not with BI (OR 1.29; p = .199). Specimen weight, rates of residual tissue not subjected to histopathological analyses, of BI and of brain tissue, on the microscopic slides differed among the neurosurgical centers (p < .001, each). Frequency of BI was increased in one department (OR 2.07; p = .002) and tended to be lower in another (OR .61; p = .088). The same centers displayed the highest and lowest rates of brain tissue in the specimen, respectively (p < .001). Moreover, the correlation of BI with the neurosurgical center was not confirmed when only analyzing specimen with evidence of brain tissue in microscopic analyses (p = .223). Detection of BI was not correlated with the intraoperative use of CUSA in subgroup analyses. Rates of brain invasion in neuropathological analyses are not associated with tumor location but differ among some neurosurgical centers. Evidence raises that surgical nuances impact specimen characteristics and therefore the accuracy of the detection of BI.

Long-term Outcome and Adverse Events of Intrathecal Opioid Therapy for Nonmalignant Pain Syndrome.

OBJECTIVE: Intrathecal (IT) opioid pumps are one therapeutic cornerstone of refractory nonmalignant pain syndromes. The aim of this study was to evaluate the efficacy of and surgical and pharmacological complications of IT pumps beyond a time span of 10 years. METHODS: In this retrospective single-center cohort study, 27 patients (14 female, 13 male, age 64.0 ± 8.9 [median, 1 SD] years) were identified. Pain intensity using the numeric rating scale (NRS), pain and IT pump characteristics, and complications were analyzed. The German Pain Questionnaire was used to investigate the physical and mental health status. RESULTS: Overall time of IT therapy from first implantation to last follow-up was 20.4 ± 6.0 years. Time to implantation of the second pump (n = 18) was 10.0 ± 5.3 years, and between the second and third pump (n = 6) 6.5 ± 2.7 years; 2 patients received their fourth pump 6 years later. The NRS score was 9.0 ± 0.9 before implantation, 7.0 ± 1.8 1 year after implantation, and 4.0 ± 2.3 at the last follow-up. IT drug dose remained stable after 3 years. Opioid intoxications occurred in 3 patients (10%). One patient (3%) underwent revision surgery due to a catheter infection. Drug side effects occurred in 4 patients (14%). Our patient group had pain-related restrictions in physical activities with menial impact regarding mental and emotional stress. CONCLUSION: Even after a time span of over 15 years and several exchanges of pump systems, pain intensity was still reduced. After 3 years, IT drug dose remained unchanged with low side-effect and complication rates.

Delayed Leukoencephalopathy and Foreign Body Reaction After Endovascular Treatment in Patients With Intracranial Aneurysms and Aneurysmal Subarachnoid Hemorrhage-A Systematic Review of the Literature.

Background: Delayed leukoencephalopathy and foreign body reaction are rare complications after endovascular treatment of intracranial aneurysms. However, cases are increasingly being described, given the rising case numbers and complexity. Methods: Clinical presentation, differentials, diagnostics, treatment, and formerly published data were reviewed in light of available cases. A systematic search of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Results: This article provides an extensive literature review of previously described cases, and discusses the causes and management of this rare and delayed complication by referring to 17 articles on this topic, with a total of 50 cases with sufficient data in the literature. Furthermore, we present the case of a 53-year-old female patient with subarachnoid hemorrhage from a large anterior communicating artery aneurysm with tortuous cervical vessels who was treated with endovascular coiling and has suffered delayed leukoencephalopathy 6 weeks after discharge. Diagnostics, treatment, and clinical course of this rare complication are presented on this case and based on formerly published literature. The patient timely recovered under high dose corticosteroid treatment and follow up MRI showed almost complete remission of the described lesions within 10 days in accordance with previously published data. Conclusion: Foreign body reaction might result in delayed leukoencephalopathy, especially following complex endovascular aneurysm treatment. Early high dose followed by low dose ongoing corticosteroid treatment might result in timely remission.

Partial "targeted" embolisation of brain arteriovenous malformations.

The treatment of pial arteriovenous brain malformations is controversial. Little is yet known about their natural history, their pathomechanisms and the efficacy and risks of respective proposed treatments. It is known that only complete occlusion of the AVM can exclude future risk of haemorrhage and that the rates of curative embolisation of AVMs with an acceptable periprocedural risk are around 20 to 50%. As outlined in the present article, however, partial, targeted embolisation also plays a role. In acutely ruptured AVMs where the source of bleeding can be identified, targeted embolisation of this compartment may be able to secure the AVM prior to definitive treatment. In unruptured symptomatic AVMs targeted treatment may be employed if a defined pathomechanism can be identified that is related to the clinical symptoms and that can be cured with an acceptable risk via an endovascular approach depending on the individual AVM angioarchitecture. This review article gives examples of pathomechanisms and angioarchitectures that are amenable to this kind of treatment strategy.

First Report of Extraspinal Lead Migration Along a Thoracic Spinal Nerve After Spinal Cord Stimulation.

BACKGROUND: Spinal cord stimulation for failed back surgery syndrome and chronic pain is a well-established treatment regimen today. Lead migration is the most common complication; mainly epidural caudal more than cranial electrode migration from the primary position is described repeatedly throughout the literature. CASE DESCRIPTION: A 60-year-old male patient with failed back surgery syndrome was eligible for spinal cord stimulation. Surgery had been performed 4 weeks before readmission with proper lead positioning of both electrodes in the midline of the epidural space. The electrode fixation mechanism at L2/3 had to be revised and was replaced with multiple ligature fixations due to the patient's slim build. He presented to our outpatient clinic with thoracic right-sided pain matching T5 with signs of overstimulation of the paravertebral muscles. X-ray imaging revealed cranial migration of 1 lead to T4 and a right-sided extraspinal migration of the other lead along a spinal nerve in T5 exiting the neuroforamen and following beneath the corresponding rib dorsally. Revision surgery was performed using a thoracic paddle electrode. CONCLUSIONS: Lead migration remains a challenge in spinal cord stimulation regardless of the fixation method. Rare unusual migration patterns in addition to simple caudal or cranial migration might pose a challenge for revision surgery and thus might reduce overall treatment efficacy.

Anticoagulation Therapy After Surgical Treatment of Spinal Dural Arteriovenous Fistula. Effectiveness and Long-Term Outcome Analysis.

OBJECTIVE: Effectiveness and safety of anticoagulation therapy (AC) after treatment of spinal dural arteriovenous fistula (sdAVF) are still inadequately discussed in the literature and are addressed in this study. METHODS: We retrospectively analyzed our medical database for patients with sdAVF treated in our institution between 2006 and 2016. Neurologic status at time of admission, discharge, and last follow-up was assessed via Aminoff-Logue disability score. Patient cohorts were dichotomized as group A (postoperative therapeutic heparinization) and group B (routine thromboembolic prophylaxis with low-dose heparin). RESULTS: Fifty-three patients were included in this analysis. In group A (n = 11), no acute deterioration was reported. In group B (n = 42), 4 patients developed acute postoperative deterioration; therapeutic AC was initiated in all 4 patients resulting in complete neurologic recovery within the inpatient stay. However, the incidence of postoperative deterioration did not reach statistical significance between treatment groups (P = 0.57). Data of 40 patients were available for long-term analysis (mean, 53.4 ± 36 months). Neurologic status did not differ significantly between both groups at time of admission (P = 0.093), discharge (P = 0.723), and last follow-up (P = 0.222). CONCLUSIONS: Acute postoperative deterioration in patients with sdAVF is a clinically relevant complication and was present in 7.5% of patients in our series. Although routine therapeutic AC did not decrease the rate of acute deterioration significantly, our findings imply that therapeutic AC in cases of acute postoperative deterioration might be a safe and efficient treatment option.

Time-of-flight-, phase contrast and contrast enhanced magnetic resonance angiography for pre-interventional determination of aneurysm size, configuration, and neck morphology in an aneurysm model in rabbits.

We describe three different magnetic resonance (MR)-angiography techniques to evaluate aneurysm size, configuration, and neck morphology of experimentally created aneurysms in a rabbit model. In five New Zealand White rabbits an aneurysm was created by endovascular occlusion of the right common carotid artery (CCA) using a pliable balloon and subsequent endoluminal incubation of elastase within the proximal CCA above the balloon and distal ligation of the vessel. In all animals, time-of-flight (TOF), phase contrast and contrast enhanced (CE) MR angiographies (MRA) were performed and compared to conventional digital subtraction angiography results. We found, that aneurysms are best visualized employing CE MRA, however, neck morphology was also found to demonstrate interpretable results when evaluating the axial source data of the TOF MRA. The animal model we used can be employed for testing endovascular devices such as new coil material, or covered stents. The described MRA techniques might then be helpful for pre-interventional planning and maybe even for the follow-up of the thus treated aneurysms.

Intraoperative three-dimensional visualization of the pyramidal tract in a neuronavigation system (PTV) reliably predicts true position of principal motor pathways.

BACKGROUND: This prospective study employs anisotropic diffusion-weighted (ADW) magnetic resonance imaging for the integration of individual spatial information concerning the principal motor pathways into the operating room during microneurosurgery in the central region. We hypothesize that the three-dimensional (3-D) visualization of the pyramidal tract position (PTV) in a neuronavigation system based on ADW provides valid information concerning the position and extension of the principal motor pathways. METHODS: A total of 13 consecutive patients with lesions adjacent to the pyramidal tracts and the central region underwent microneurosurgery with the help of pyramidal tract visualization (PTV). An ADW sequence obtained preoperatively was fused to an anatomic navigation sequence. The 3-D reconstructions of the precentral gyrus (PG), the pyramidal tract, and the tumor were available in a customized neuronavigation system during surgery. Intraoperatively the PG was identified on the basis of the aforementioned data. Electric motorcortex stimulation (CS) was used to directly verify the PG location and indirectly the fiber tract position. RESULTS: In 11 cases (92%) the prediction of the principal motor pathways' position was correct. In one case of a meningioma, according to PTV, the tumor was falsely localized postcentrally. In the case of a precentral cavernoma, no motor response could be elicited by cortical stimulation. CONCLUSION: Intraoperative PTV on the basis of ADW provides the neurosurgeon with reliable information concerning the position of the principal motor pathways during intracranial procedures as proved with intraoperative electrophysiological testing. The technique has the potential to reduce operative morbidity. PTV is straightforward and can be adapted to other customized neuronavigation devices.

Solitary plasmacytoma presenting as an intramedullary mass of the cervical cord.

Extramedullary plasmacytomas originating in the spinal cord are extremely rare lesions. We report a 52-year-old man presenting with progressive tetraparesis. Spinal magnetic resonance imaging (MRI) showed an ill-defined contrast-enhancing intramedullary mass at the C5-6 level. After a biopsy was taken, pathology including immunohistochemistry revealed plasmacytoma. Complete workup for multiple myeloma was negative. The patient was treated with intravenous chemotherapy followed by radiotherapy and corticosteroids without any improvement of the clinical symptoms or decreased tumor size on the follow-up MRIs. The most common spinal manifestation of plasmocytoma is involvement of the vertebral bodies leading to extradural compression of the cord. Only rarely plasmocytoma manifests itself as a primarily dural lesion leading to an intradural cord compression. This report describes the extremely rare manifestation of plasmocytoma of the spinal cord itself that therefore should be considered in the differential diagnosis of spinal cord mass lesions.

Experience with a gravitational valve in the management of symptomatic overdrainage in children with shunts.

OBJECT: Symptomatic overdrainage in children with shunt-treated hydrocephalus represents one of the more difficult shunt-related diseases and may require repeated surgery. Gravity-assisted valve design has become a standard device to avoid overdrainage in many European pediatric hydrocephalus centers. However, the use of a gravitational valve for relieving symptoms associated with overdrainage has not yet been addressed. The goal of this study was to evaluate the effectiveness of a gravitational valve in the treatment of symptomatic overdrainage in children with shunts. METHODS: Seventeen children with an adjustable shunt system and symptomatic overdrainage were treated by insertion of a gravitational valve. Clinical and radiological outcome were monitored for a minimum of 12 months after surgery. RESULTS: Implantation of a gravitational valve resulted in either resolution (n = 12) or improvement (n = 5) of the symptoms. In 1 patient, symptoms remained almost unchanged and the gravitational valve had to be upgraded, resulting in resolution of the symptoms. During follow-up, the pressure setting of the adjustable differential pressure valve had to be changed in 7 patients. CONCLUSIONS: The gravitational valve was effective in improving symptomatic overdrainage in the majority of patients in the present study. Because the ideal pressure setting for a given patient is hard to determine a priori, adjustable valve systems appear to be beneficial.

Intracranial aneurysms: from vessel wall pathology to therapeutic approach.

An aneurysm is a focal dilatation of an arterial blood vessel. Luminal forces, such as high blood flow, shear stress and turbulence, are implicated in the pathogenesis of intracranial aneurysms, and luminal characteristics, such as sac size and morphology, are usually essential to the clinical decision-making process. Despite frequent clinical emphasis on the vessel lumen, however, the pathology underlying the formation, growth and rupture of an aneurysm mainly resides in the vessel wall. Research on the morphology and histopathology of the vessel wall reveals that intracranial aneurysms do not constitute a single disease, but are a shared manifestation of a wide range of diseases, each of which has a unique natural history and optimum therapy. This Review classifies intracranial aneurysms by vessel wall pathology, and demonstrates that understanding the morphology and pathology of this structure is important in determining the therapeutic approach. The article concludes that aneurysms represent a symptom of an underlying vascular disease rather than constituting a disease on their own.

Cortisol dynamics in the acute phase of aneurysmal subarachnoid hemorrhage: associations with disease severity and outcome.

The purpose of this study was to assess cortisol dynamics in the acute phase after aneurysmal subarachnoid hemorrhage (SAH) and to set the parameters of cortisol release in relation to the severity of illness and outcome. In 22 consecutive patients with aneurysmal SAH, cortisol, corticosteroid binding globulin, interleukin-6, and adrenocorticotrophic hormone were measured immediately after hospital admission (t(0)), 7 days (t(1)) later, and at least 14 days later (t(2)). Additionally, diurnal profiles of cortisol secretion were assessed at t(1) and t(2), and area under the curve (AUC) was computed for calculated free serum cortisol (CFSC). In this study, normal diurnal CFSC profiles were associated with a significantly shorter ICU-stay, less complications, and a more favorable outcome than abnormal diurnal profiles. AUC and 8 a.m. cortisol were not related to clinical course or outcome. It is concluded that cortisol secretion patterns are associated with the severity and outcome of SAH. For an appraisal of the hypothalamo-pituitary-adrenal axis in SAH patients, single cortisol measurements are insufficient.

How useful is the 3-dimensional, surgeon's perspective-adjusted visualisation of the vessel anatomy during aneurysm surgery? A prospective clinical trial.

We hypothesized that neuronavigational 3-dimensional display of vessel and aneurysm anatomy, which is adjusted to the actual surgeon's view, could be helpful during the critical steps of aneurysm treatment. A total number of 32 patients with 42 aneurysms entered this prospective clinical trial. With a neuronavigational system, a 3-dimensional image of the arterial vascular anatomy was generated by autosegmentation of a computerized tomography (CT) angiographic data set. The 3-dimensional image was then adjusted to the surgeon's perspective by rotation. The neurosurgeon linked the 3-dimensional image information with the vascular structures in his surgical field by a neuronavigational pointer. He had the opportunity to further rotate the image with the displayed pointer for visualization of hidden structures. After operation, the neurosurgeon had to define with which expectations neuronavigation was applied and to evaluate if these expectations were fulfilled. The expectations with which the neurosurgeon used neuronavigation were to localize the aneurysm (n = 24), to understand the branching anatomy (n = 18), to visualize hidden structures (n = 8), to evaluate the projection of the aneurysm dome (n = 5) and to tailor the approach (n = 2). In 5 of the 42 aneurysms that were either very small or located in close vicinity to the skull base, the neurosurgeon's expectations were not fulfilled. A favorable outcome was achieved in 29 of the 32 patients (91%). Neuronavigational 3-dimensional display of the vessel anatomy was considered useful by the vascular neurosurgeon. Possibly, this technique has the potential to improve operative results by reduction of the surgical trauma and avoidance of intraoperative complications.

Sequential visualization of brain and fiber tract deformation during intracranial surgery with three-dimensional ultrasound: an approach to evaluate the effect of brain shift.

OBJECTIVE: We present a technique that allows intraoperative display of brain shift and its effects on fiber tracts. METHODS: Three patients had intracranial lesions (one malignant glioma, one metastasis, and one cavernoma) in contact with either the corticospinal or the geniculostriate tract that were removed microneurosurgically. Preoperatively, magnetic resonance diffusion-weighted imaging (DWI) was performed to visualize the fiber tract at risk. DWI data were fused with those obtained from anatomic T1-weighted magnetic resonance imaging. A single-rack three-dimensional ultrasound neuronavigation system, which simultaneously displays the MRI scan and the corresponding ultrasound image, was used intraoperatively for 1) navigation; 2) definition of fixed and potentially shifting ultrasound landmarks near the fiber tract; and 3) sequential image updating at different steps of resection. The result was time-dependent brain deformation data. With a standard personal computer equipped with standard image software, the brain shift-associated fiber tract deformation was assessed by use of sequential landmark registration. After surgery, DWI was performed to confirm the predicted fiber tract deformation. RESULTS: The lesions were removed without morbidity. Comparison of three-dimensional ultrasound with DWI and T1-weighted magnetic resonance imaging data allowed us to define fixed and potentially shifting landmarks close to the respective fiber tract. Postoperative DWI confirmed that the actual fiber tract position at the conclusion of surgery corresponded to the sonographically predicted fiber tract position. CONCLUSION: By definition and sequential intraoperative registration of ultrasound landmarks near the fiber tract, brain shift-associated deformation of a tract that is not visible sonographically can be assessed correctly. This approach seems to help identify and avoid eloquent brain areas during intracranial surgery.

Prospective demonstration of short-term motor plasticity following acquired central pareses.

The effect of newly acquired central pareses on functional MRI (fMRI) signal pattern is not known, since up to now all investigated patients were examined while they already experienced the motor weakness. We describe the first prospective and controlled study demonstrating the impact of new, acquired central pareses on fMRI motor activation pattern. Six patients suffering from a new central paresis after resection of a brain tumor infiltrating the central region were prospectively compared with a control group of five patients without postoperative paresis and a group of six healthy, age-matched controls who were investigated at two time points. fMRI signal was postoperatively analyzed during the performance of hand motor tasks and compared to the preoperative fMRI results. The relative signal change between rest and activation was evaluated for five cortical regions: the primary motor cortex (M1) and the ipsilateral primary motor cortex (M1i), the supplementary motor area (SMA), the premotor area (PMA), and the superior parietal lobule (SPL). In the patients with new postoperative central pareses, significant (P = 0.0313) decreases in fMRI activation were found in M1, whereas significant (P = 0.0313) increases were found in SMA and PMA. For M1i and SPL, there was a signal increase on average as well, but it failed to reach significance (P = 0.1250). In both control groups, no significant changes between both examinations were seen. Even though the number of investigated patients is too small to draw definite conclusions, our results support the concept of short-term motor plasticity being mediated by redundant systems that may take over function after damage of the primary motor cortex. The findings potentially also reflect increased functional demands imposed upon the motor network subsequent to a loss of dexterity.

A refined method for creating saccular aneurysms in the rabbit.

We describe a refined animal model of human intracerebral aneurysms for testing endovascular devices for interventional neuroradiological procedures. Saccular aneurysms resulting from a stump of the right common carotid artery (CCA) were created in 15 New Zealand White rabbits by intraluminal incubation of elastase that was applied to the CCA after distal ligation of the CCA and proximal occlusion of the vessel using a pliable balloon. Subsequently a microcatheter was advanced to a position cranial to the balloon and the elastase was infused under fluoroscopic guidance to avoid retrograde flow to the trachea via aberrant vessels. Contrast-enhanced (CE) MRA at 1.5 T and conventional digital subtraction angiography was performed to test for aneurysm size, morphology and neck anatomy. In all 15 animals aneurysms resulted from the stump of the right CCA, ranging in size from 2.0 to 9.9 mm (mean 6.3 mm) in craniocaudal direction, 1.0 to 5.5 mm (mean 3.8 mm) in mediolateral direction and 1.0 to 3.8 mm (mean 2.4 mm) in neck diameter. Aneurysm morphology could be adequately demonstrated using CE MRA. On histological evaluation a loss of the internal elastic lamina was noted. The described method represents an easy, reliable, and reproducible method of aneurysm creation in the rabbit in an area of high shear stress. These aneurysms can be used for testing new endovascular devices for embolization of intracranial aneurysms.