Risk of de novo aneurysm formation in patients previously diagnosed with a ruptured or unruptured aneurysm: 18-year follow-up.

BACKGROUND: Data on de novo aneurysm formation after treatment for intracranial aneurysms remains scarce. We studied the incidence of de novo aneurysm formation in patients who had undergone aneurysm treatment more than 18 years prior to follow-up. As it is a disease affecting a younger patient population more specific guidelines are needed when planning a follow-up regime. METHODS: The rate of de novo aneurysm formation was assessed with Magnetic Resonance Angiography (MRA) follow-up >18 years after endovascular or microsurgical treatment for an intracranial aneurysm. Variables associated with de novo aneurysm formation were studied using logistic regression. Missing data were imputed using chained random forests. A data-driven model for the prediction of de novo aneurysm was created to calculate the relative variable importance of ten clinical features. RESULTS: De novo aneurysms were identified in 11/81 (13.6 %) patients, of whom 1 was male, over a median follow-up of 20 years. Sex was the most important variable associated with de novo aneurysm formation. Regarding the development of de novo aneurysm, men displayed an odds ratio (OR) of 0.16 (0.01-0.97), compared with women. OR for mRS score 2 or more was 0.20 (95 % CI 0.01-1.34), and OR for smokers was 3.70 (0.54-31.18). Six out of 11 patients (54.5 %) needed treatment; 1 underwent endovascular treatment (EVT) and 5 underwent microsurgical treatment (MST). The overall annual de novo aneurysm formation rate was 0.92 %. CONCLUSIONS: This study highlights the need for a longer follow-up imaging monitoring of patients that have previously undergone treatment for an intracranial aneurysm. These data are useful to take into consideration when planning a follow-up strategy.

[Considerations when handling common acute intracranial vascular anomalies]. / Akuta vaskulära neurokirurgiska tillstånd kräver snabb hantering.

Conditions involving intracranial vascular anomalies are increasingly diagnosed, not least incidentally, with the increasing availability of neuroradiological investigations. Acute deterioration and development of symptoms due to a vascular condition could require neurosurgical intervention depending on the nature of the condition and status of the patient. On the other hand, asymptomatic patients with incidental findings require careful consideration and risk assessment when deciding on whether or not to treat the condition, and if so, how. In this review article we provide a summary of some of the most common neurosurgical vascular conditions and outline management considerations in both the acute and elective setting.

Intra-arterial nimodipine for severe cerebral vasospasm after aneurysmal subarachnoid haemorrhage - neurological and radiological outcome.

OBJECTIVES: Cerebral vasospasm is a known complication to aneurysmal subarachnoid haemorrhage, which can lead to severe morbidity. Intra-arterial vasodilation therapy is widely used as a last resort treatment in patients with symptomatic refractory cerebral vasospasm but there is limited data about the outcome. The purpose of this study is to evaluate the neurological and radiological outcome in patients treated with intra-arterial nimodipine in relation to cerebral infarction, procedure-related complications and clinical outcome. METHODS: Patients with refractory cerebral vasospasm treated with intra-arterial nimodipine during 2009-2020 at Sahlgrenska University Hospital were retrospectively reviewed. Neurological outcome (modified Rankin Scale) at 30 days and 6 months, development of cerebral infarction after intra-arterial nimodipine treatment and procedure-related complications were studied. RESULTS: Forty-eight patients were treated with intra-arterial nimodipine. A good outcome (modified Rankin Scale 0-2) was seen in 25% (n = 12) of the patients after 30 days and in 47% (n = 22) of the patients after six months. Infarction related to the vasospastic vessel after treatment with intra-arterial nimodipine was seen in 60% (n = 29) of the patients. A total of 124 procedures with intra-arterial nimodipine were performed where complications were seen in 10 (21%) patients in 10 (8%) procedures. Four (8%) patients died within 30 days. CONCLUSIONS: A majority of patients developed an ischaemic cerebral infarction in spite of intra-arterial nimodipine treatment. However, a good clinical recovery was seen in almost half of the patients after 6 months. Minor complications occurred in one out of five patients.

Neurological Outcome, Mental Fatigue, and Occurrence of Aneurysms >15 Years After Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: Long-term data on neurological and radiological outcome after aneurysmal subarachnoid hemorrhage (aSAH) are scarce. The aim of this study was to report neurological and radiological outcome >15 years after aSAH. METHODS: Patients with aSAH who were randomly assigned to endovascular treatment (EVT) or microsurgical treatment (MST) during 1997-2001 were included. Main end points were neurological outcome assessed by modified Rankin Scale, fatigue assessed by mental fatigue scale, and radiological outcome assessed by magnetic resonance angiography. Results for mental fatigue scale were compared with a control group. RESULTS: After 15-21 years, 46 (62.2%) of the 74 survivors replied to a questionnaire. Of these patients, 18 received MST, and 28 received EVT. Modified Rankin Scale score of 0-2 was found in 100% of patients in the EVT group and 88.8% of patients in the MST group. Moderate or severe mental fatigue was found in 7/28 patients (25%) in the EVT group and 7/18 patients (38.8%) in the MST group (P < 0.05), whereas moderate or severe mental fatigue was observed in 3/34 patients (8.9%) in the control group. Magnetic resonance angiography was performed in 29 patients. In the EVT group, new neck remnants were found in 2/16 patients (12.5%), and de novo aneurysm was found in 2/16 patients (12.5%). In the MST group, de novo aneurysm was found in 1/13 patients (7.7%). CONCLUSIONS: Neurological outcome at long-term follow-up after aSAH was good; however, mental fatigue was overrepresented in patients compared with healthy control subjects regardless of treatment modality. Residual or de novo aneurysm was found in 17% of patients warranting radiological long-term follow-up.

Repetitive transcranial magnetic stimulation of the primary motor cortex in management of chronic neuropathic pain: a systematic review.

OBJECTIVES: Repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex (M1) with frequencies 5-20 Hz is an expanding non-invasive treatment for chronic neuropathic pain (NP). Outcome data, however, show considerable inhomogeneity with concern to the levels of effect due to the great diversity of treated conditions. The aim of this review was to survey the literature regarding the efficacy and safety of M1 rTMS, and the accuracy to predict a positive response to epidural motor cortex stimulation (MCS) which is supposed to give a more longstanding pain relief. METHODS: A systematic literature search was conducted up to June 2019 in accordance with the PRISMA guidelines. We used the PICO Model to define two specific clinical questions: (1) Does rTMS of M1 relieve NP better than sham treatment? (2) Can the response to rTMS be used to predict the effect of epidural MCS? After article selection, data extraction, and study quality assessment, the certainty of evidence of treatment effect was defined using the GRADE system. RESULTS: Data on 5-20 Hz (high-frequency) rTMS vs. sham was extracted from 24 blinded randomised controlled trials which were of varying quality, investigated highly heterogeneous pain conditions, and used excessively variable stimulation parameters. The difference in pain relief between active and sham stimulation was statistically significant in 9 of 11 studies using single-session rTMS, and in 9 of 13 studies using multiple sessions. Baseline data could be extracted from 6 single and 12 multiple session trials with a weighted mean pain reduction induced by active rTMS, compared to baseline, of -19% for single sessions, -32% for multiple sessions with follow-up <30 days, and -24% for multiple sessions with follow-up ≥30 days after the last stimulation session. For single sessions the weighted mean difference in pain reduction between active rTMS and sham was 15 percentage points, for multiple sessions the difference was 22 percentage points for follow-ups <30 days, and 15 percentage points for follow-ups ≥30 days. Four studies reported data that could be used to evaluate the accuracy of rTMS to predict response to MCS, showing a specificity of 60-100%, and a positive predictive value of 75-100%. No serious adverse events were reported. CONCLUSIONS: rTMS targeting M1 can result in significant reduction of chronic NP which, however, is transient and shows a great heterogeneity between studies; very low certainty of evidence for single sessions and low for multiple sessions. Multiple sessions of rTMS can maintain a more longstanding effect. rTMS seems to be a fairly good predictor of a positive response to epidural MCS and may be used to select patients for implantation of permanent epidural electrodes. More studies are needed to manifest the use of rTMS for this purpose. Pain relief outcomes in a longer perspective, and outcome variables other than pain reduction need to be addressed more consistently in future studies to consolidate the applicability of rTMS in routine clinical practice.

Prediction of Electrode Contacts for Clinically Effective Deep Brain Stimulation in Essential Tremor.

BACKGROUND/AIM: Deep brain stimulation (DBS) is an established neurosurgical treatment that can be used to alleviate symptoms in essential tremor (ET) and other movement disorders. The aim was to develop a method and software tool for the prediction of effective DBS electrode contacts based on probabilistic stimulation maps (PSMs) in patients with ET treated with caudal zona incerta (cZi) DBS. METHODS: A total of 33 patients (37 leads) treated with DBS were evaluated with the Essential Tremor Rating Scale (ETRS) 12 months after surgery. In addition, hand tremor and hand function (ETRS items 5/6 and 11-14) were evaluated for every contact during stimulation with best possible outcome without inducing side effects. Prediction of effective DBS electrode contacts was carried out in a retrospective leave-one-out manner based on PSMs, simulated stimulation fields, and a scoring function. Electrode contacts were ranked according to their likelihood of being included in the clinical setting. Ranked electrode contacts were compared to actual clinical settings. RESULTS: Predictions made by the software tool showed that electrode contacts with rank 1 matched the clinically used contacts in 60% of the cases. Contacts with a rank of 1-2 and 1-3 matched the clinical contacts in 83 and 94% of the cases, respectively. Mean improvement of hand tremor and hand function was 79 ± 21% and 77 ± 22% for the clinically used and the predicted electrode contacts, respectively. CONCLUSIONS: Effective electrode contacts can be predicted based on PSMs in patients treated with cZi DBS for ET. Predictions may in the future be used to reduce the number of clinical assessments that are carried out before a satisfying stimulation setting is defined.

Deep Brain Stimulation of the Caudal Zona Incerta: Tremor Control in Relation to the Location of Stimulation Fields.

BACKGROUND: The caudal zona incerta (cZi) and posterior subthalamic area (PSA) are an emerging deep brain stimulation (DBS) target for essential tremor (ET). OBJECTIVES: To evaluate the efficacy of tremor control in relation to the anatomical locations of stimulation fields in 50 patients with ET and DBS of the cZi. METHODS: A total of 240 contacts were evaluated separately with monopolar stimulation, and amplitudes were optimized for improvement of tremor and hand function. Stimulation fields, i.e., volumes of neural activation, were simulated for each optimized setting and assembled into probabilistic stimulation maps (PSMs). RESULTS: There were differences in the anatomical distribution of PSMs associated with good versus poor tremor control. The location of PSMs which achieved good and excellent tremor control corresponded well with the PSM for the clinically used settings, and they were located within the superior part of the PSA. CONCLUSIONS: PSMs may serve as a useful tool for defining the most efficacious anatomical location of stimulation. The best tremor control in this series of cZi DBS was achieved with stimulation of the superior part of the PSA, which corresponds to the final part of the cerebellothalamic projections before they reach the ventral lateral thalamus.

Surgical Replacement of Implantable Pulse Generators in Deep Brain Stimulation: Adverse Events and Risk Factors in a Multicenter Cohort.

BACKGROUND: Deep brain stimulation (DBS) is a growing treatment modality, and most DBS systems require replacement of the implantable pulse generator (IPG) every few years. The literature regarding the potential impact of adverse events of IPG replacement on the longevity of DBS treatments is rather scarce. OBJECTIVE: To investigate the incidence of adverse events, including postoperative infections, associated with IPG replacements in a multicenter cohort. METHODS: The medical records of 808 patients from one Australian and five Swedish DBS centers with a total of 1,293 IPG replacements were audited. A logistic regression model was used to ascertain the influence of possible predictors on the incidence of adverse events. RESULTS: The overall incidence of major infections was 2.3% per procedure, 3.7% per patient and 1.7% per replaced IPG. For 28 of 30 patients this resulted in partial or complete DBS system removal. There was an increased risk of infection for males (OR 3.6, p = 0.026), and the risk of infection increased with the number of prior IPG replacements (OR 1.6, p < 0.005). CONCLUSIONS: The risk of postoperative infection with DBS IPG replacement increases with the number of previous procedures. There is a need to reduce the frequency of IPG replacements.