Lead Migration in Neuromodulation Mollica, Semira; Awad, Mohammed; Teddy, Peter J.
Journal of clinical neuroscience,
August 2021, 2021-08-00, 20210801, Letnik:
90
Journal Article
Recenzirano
•Lead migration in neuromodulation is common complication.•A simple technique of securing leads.•Lead securing can significantly decrease the occurrence of lead migration.
We describe a simple ...technique of securing surgically implanted leads for spinal cord (SCS), dorsal root ganglion (DRG) and occipital nerve stimulation (ONS), for both primary surgical implantation and correcting lead migration. This technique could also be adapted for securing percutaneously implanted leads. Thirty-nine patients underwent neurosurgical implantation of SCS, DRG, and ONS devices utilizing titanium mini-plates to obtain secure anchorage of leads to adjacent laminae close to their exit point from the epidural space, thereby minimizing the risk of further lead migration or electrode displacement. There were no cases of primary or recurrent lead migration in any patient undergoing lead placement using mini-plate anchorage. The technique appears to offer a reliable means of preventing post-operative lead migration in a variety of spinal and extra-cranial neuromodulation implants.
Water exchange is increasingly recognized as an important biological process that can affect the study of biological tissue using diffusion MR. Methods to measure exchange, however, remain immature ...as opposed to those used to characterize restriction, with no consensus on the optimal pulse sequence (s) or signal model (s). In general, the trend has been towards data-intensive fitting of highly parameterized models. We take the opposite approach and show that a judicious sub-sample of diffusion exchange spectroscopy (DEXSY) data can be used to robustly quantify exchange, as well as restriction, in a data-efficient manner. This sampling produces a ratio of two points per mixing time: (i) one point with equal diffusion weighting in both encoding periods, which gives maximal exchange contrast, and (ii) one point with the same total diffusion weighting in just the first encoding period, for normalization. We call this quotient the Diffusion EXchange Ratio (DEXR). Furthermore, we show that it can be used to probe time-dependent diffusion by estimating the velocity autocorrelation function (VACF) over intermediate to long times (∼2−500ms). We provide a comprehensive theoretical framework for the design of DEXR experiments in the case of static or constant gradients. Data from Monte Carlo simulations and experiments acquired in fixed and viable ex vivo neonatal mouse spinal cord using a permanent magnet system are presented to test and validate this approach. In viable spinal cord, we report the following apparent parameters from just 6 data points: τk=17±4ms, fNG=0.72±0.01, Reff=1.05±0.01μm, and κeff=0.19±0.04μm/ms, which correspond to the exchange time, restricted or non-Gaussian signal fraction, an effective spherical radius, and permeability, respectively. For the VACF, we report a long-time, power-law scaling with ≈t−2.4, which is approximately consistent with disordered domains in 3-D. Overall, the DEXR method is shown to be highly efficient, capable of providing valuable quantitative diffusion metrics using minimal MR data.
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•A rapid measurement based on diffusion exchange spectroscopy is proposed.•Using just two points per mixing time, exchange can be isolated from restriction.•Both restriction and exchange parameters can be extracted from the same data.•Time-dependence can also be measured via the velocity autocorrelation function.•Data from Monte Carlo simulations and mouse spinal cord are presented.
Factors contributing to cerebral edema in the post-hyperacute period of ischemic stroke (first 24-72 hours) are poorly understood. Blood-brain barrier (BBB) disruption and postischemic hyperperfusion ...reflect microvascular dysfunction and are associated with hemorrhagic transformation. We investigated the relationships between BBB integrity, cerebral blood flow, and space-occupying cerebral edema in patients who received acute reperfusion therapy.
We performed a pooled analysis of patients treated for anterior circulation large vessel occlusion in the EXTEND-IA TNK and EXTEND-IA TNK part 2 trials who had MRI with dynamic susceptibility contrast-enhanced perfusion-weighted imaging 24 hours after treatment. We investigated the associations between BBB disruption and cerebral blood flow within the infarct with cerebral edema assessed using 2 metrics: first midline shift (MLS) trichotomized as an ordinal scale of negligible (<1 mm), mild (≥1 to <5 mm), or severe (≥5 mm), and second relative hemispheric volume (rHV), defined as the ratio of the 3-dimensional volume of the ischemic hemisphere relative to the contralateral hemisphere.
Of 238 patients analyzed, 133 (55.9%) had negligible, 93 (39.1%) mild, and 12 (5.0%) severe MLS at 24 hours. The associated median rHV was 1.01 (IQR, 1.00-1.028), 1.03 (IQR, 1.01-1.077), and 1.15 (IQR, 1.08-1.22), respectively. MLS and rHV were associated with poor functional outcome at 90 days (
.002). Increased BBB permeability was independently associated with more edema after adjusting for age, occlusion location, reperfusion, parenchymal hematoma, and thrombolytic agent used (MLS cOR, 1.12 95% CI, 1.03-1.20,
=0.005; rHV β, 0.39 95% CI, 0.24-0.55,
<0.0001), as was reduced cerebral blood flow (MLS cOR, 0.25 95% CI, 0.10-0.58,
=0.001; rHV β, -2.95 95% CI, -4.61 to -11.29,
=0.0006). In subgroup analysis of patients with successful reperfusion (extended Treatment in Cerebral Ischemia 2b-3, n=200), reduced cerebral blood flow remained significantly associated with edema (MLS cOR, 0.37 95% CI, 0.14-0.98,
=0.045; rHV β, -2.59 95% CI, -4.32 to -0.86,
=0.004).
BBB disruption and persistent hypoperfusion in the infarct after reperfusion treatment is associated with space-occupying cerebral edema. Further studies evaluating microvascular dysfunction during the post-hyperacute period as biomarkers of poststroke edema and potential therapeutic targets are warranted.
Abstract
Objective
To conduct a comprehensive search for evidence with regard to whether central sensitization after an injury can act as a persistent autonomous pain generator after the inducing ...injury has healed.
Methods
We searched Medline on PubMed and the Cochrane Library, screening 3,572 abstracts, from which 937 full-text articles were obtained, with 186 of these discarded as irrelevant to the question being posed. The remaining 751 articles were studied for evidence.
Results
Fourteen publications were judged to provide weak evidence for the hypothesis of central sensitization as a persisting autonomous pain generator, but none addressed the question directly. No strong evidence for the affirmative answer was found. Sixty-one publications were judged to provide weak evidence for a negative answer, and ten were judged to provide strong evidence. Unexpectedly, serious weaknesses were discovered in the literature underpinning the validity of the clinical diagnosis of central sensitization in humans: 1) inappropriate extrapolation, in many publications, of laboratory animal data to humans; 2) failure to demonstrate the absence of peripheral pain generators that might be perpetuating central sensitization; and 3) many factors now shown to confound what is being measured by quantitative sensory testing, conditioned pain modulation, and the Central Sensitization Inventory.
Conclusions
We found no evidence proving that central sensitization can persist as an autonomous pain generator after the initiating injury has healed. Our review has also shown that the evidential basis for the diagnosis of central sensitization in individual patients is seriously in question.
We develop magnetic resonance (MR) methods for real-time measurement of tissue microstructure and membrane permeability of live and fixed excised neonatal mouse spinal cords. Diffusion and exchange ...MR measurements are performed using the strong static gradient produced by a single-sided permanent magnet. Using tissue delipidation methods, we show that water diffusion is restricted solely by lipid membranes. Most of the diffusion signal can be assigned to water in tissue which is far from membranes. The remaining 25% can be assigned to water restricted on length scales of roughly a micron or less, near or within membrane structures at the cellular, organelle, and vesicle levels. Diffusion exchange spectroscopy measures water exchanging between membrane structures and free environments at 100 s
.
Objective
The objective of this study was to evaluate functional and safety outcomes of endovascular thrombectomy (EVT) versus medical management (MM) in patients with M2 occlusion and examine their ...association with perfusion imaging mismatch and stroke severity.
Methods
In a pooled, patient‐level analysis of 3 randomized controlled trials (EXTEND‐IA, EXTEND‐and IA‐TNK parts 1 and 2) and 2 prospective nonrandomized studies (INSPIRE and SELECT), we evaluated EVT association with 90‐day functional independence (modified Rankin Scale mRS = 0–2) in isolated M2 occlusions as compared to medical management overall and in subgroups by mismatch profile status and stroke severity.
Results
We included 517 patients (EVT = 195 and MM = 322), baseline median (interquartile range IQR) National Institutes of Health Stroke Scale (NIHSS) was 13 (8–19) in EVT versus 10 (6–15) in MM, p < 0.001. Pretreatment ischemic core did not differ (EVT = 10 0–24 ml vs MM = 9 3–21 ml, p = 0.59). Compared to MM, EVT was more frequently associated with functional independence (68.3 vs 61.6%, adjusted odds ratio aOR = 2.42, 95% confidence interval CI = 1.25–4.67, p = 0.008, inverse probability of treatment weights IPTW‐OR = 1.75, 95% CI = 1.00–3.75, p = 0.05) with a shift toward better mRS outcomes (adjusted cOR = 2.02, 95% CI:1.23–3.29, p = 0.005), and lower mortality (5 vs 10%, aOR = 0.32, 95% CI = 0.12–0.87, p = 0.025). EVT was associated with higher functional independence in patients with a perfusion mismatch profile (EVT = 70.7% vs MM = 61.3%, aOR = 2.29, 95% CI = 1.09–4.79, p = 0.029, IPTW‐OR = 2.02, 1.08–3.78, p = 0.029), whereas no difference was found in those without mismatch (EVT = 43.8% vs MM = 62.7%, p = 0.17, IPTW‐OR: 0.71, 95% CI = 0.18–2.78, p = 0.62). Functional independence was more frequent with EVT in patients with moderate or severe strokes, as defined by baseline NIHSS above any thresholds from 6 to 10, whereas there was no difference between groups with milder strokes below these thresholds.
Interpretation
In patients with M2 occlusion, EVT was associated with improved clinical outcomes when compared to MM. This association was primarily observed in patients with a mismatch profile and those with higher stroke severity. ANN NEUROL 2022;91:629–639
To investigate the efficacy of tenecteplase (TNK), a genetically modified variant of alteplase with greater fibrin specificity and longer half-life than alteplase, prior to endovascular thrombectomy ...(EVT) in patients with basilar artery occlusion (BAO).
To determine whether TNK is associated with better reperfusion rates than alteplase prior to EVT in BAO, clinical and procedural data of consecutive patients with BAO from the Basilar Artery Treatment and Management (BATMAN) registry and the Tenecteplase vs Alteplase before Endovascular Therapy for Ischemic Stroke (EXTEND-IA TNK) trial were retrospectively analyzed. Reperfusion >50% or absence of retrievable thrombus at the time of the initial angiogram was evaluated.
We included 110 patients with BAO treated with IV thrombolysis prior to EVT (mean age 69 SD 14 years; median NIH Stroke Scale score 16 interquartile range (IQR) 7-32). Nineteen patients were thrombolysed with TNK (0.25 mg/kg or 0.40 mg/kg) and 91 with alteplase (0.9 mg/kg). Reperfusion >50% occurred in 26% (n = 5/19) of patients thrombolysed with TNK vs 7% (n = 6/91) thrombolysed with alteplase (risk ratio 4.0, 95% confidence interval 1.3-12;
= 0.02), despite shorter thrombolysis to arterial puncture time in the TNK-treated patients (48 IQR 40-71 minutes) vs alteplase-treated patients (110 IQR 51-185 minutes;
= 0.004). No difference in symptomatic intracranial hemorrhage was observed (0/19 0% TNK, 1/91 1% alteplase;
= 0.9).
TNK may be associated with an increased rate of reperfusion in comparison with alteplase before EVT in BAO. Randomized controlled trials to compare TNK with alteplase in patients with BAO are warranted.
NCT02388061 and NCT03340493.
This study provides Class III evidence that TNK leads to higher reperfusion rates in comparison with alteplase prior to EVT in patients with BAO.
Objective
Tenecteplase improves reperfusion compared to alteplase in patients with large vessel occlusions. To determine whether this improvement varies across the spectrum of thrombolytic agent to ...reperfusion assessment times, we performed a comparative analysis of tenecteplase and alteplase reperfusion rates.
Methods
Patients with large vessel occlusion and treatment with thrombolysis were pooled from the Melbourne Stroke Registry, and the EXTEND‐IA and EXTEND‐IA TNK trials. The primary outcome, thrombolytic‐induced reperfusion, was defined as the absence of retrievable thrombus or >50% reperfusion at imaging reassessment. We compared the treatment effect of tenecteplase and alteplase, accounting for thrombolytic to assessment exposure times, via Poisson modeling. We compared 90‐day outcomes of patients who achieved reperfusion with a thrombolytic to patients who achieved reperfusion via endovascular therapy using ordinal logistic regression.
Results
Among 893 patients included in the primary analysis, thrombolytic‐induced reperfusion was observed in 184 (21%) patients. Tenecteplase was associated with higher rates of reperfusion (adjusted incidence rate ratio aIRR = 1.50, 95% confidence interval CI = 1.09–2.07, p = 0.01). Findings were consistent in patient subgroups with first segment (aIRR = 1.41, 95% CI = 0.93–2.14) and second segment (aIRR = 2.07, 95% CI = 0.98–4.37) middle cerebral artery occlusions. Increased thrombolytic to reperfusion assessment times were associated with reperfusion (tenecteplase: adjusted risk ratio aRR = 1.08 per 15 minutes, 95% CI = 1.04–1.13 vs alteplase: aRR = 1.06 per 15 minutes, 95% CI = 1.00–1.13). No significant treatment‐by‐time interaction was observed (p = 0.87). Reperfusion via thrombolysis was associated with improved 90‐day modified Rankin Scale scores (adjusted common odds ratio = 2.15, 95% CI = 1.54–3.01) compared to patients who achieved reperfusion following endovascular therapy.
Interpretation
Tenecteplase, compared to alteplase, increases prethrombectomy reperfusion, regardless of the time from administration to reperfusion assessment. Prethrombectomy reperfusion is associated with better clinical outcomes. ANN NEUROL 2023;93:489–499
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