Severity Of Denervation Research Articles

Гистоморфометрическая оценка большеберцового нерва и мелких мышц стопы после внутреннего невролиза и аутогенной пластики большеберцовой порции седалищного нерва крыс

Introduction Transformations of the nerves and muscles of the distal extremities after nerve injuries at the level of the proximal segments are critical for the restoration of functions, but have not been sufficiently studied in experimental biological models. Purpose Histomorphometric evaluation of the tibial nerves and plantar interosseous muscles after internal neurolysis and autogenous plasty of the tibial portion of the sciatic nerve (SN) in rats. Materials and methods The study was performed on 21 male Wistar rats, aged 8-10 months. Series 1 (internal SN neurolysis) – n = 6. Series 2 (autogenous SN neuroplasty) – n = 8. Control – 7 intact rats. The rats were euthanized 6 months after the operation. Light microscopy and histomorphometry of transverse semithin sections of the tibial nerve at the level of the middle third of the lower leg and paraffin sections of the plantar interosseous muscles of the foot were performed. Results In series 1, endoneural vessels had increased diameters and wall thickness in the tibial nerve, but a smaller lumen compared to the norm; the dimensional characteristics of the myelinated fiber population were increased due to myelin decompactization and axonal edema; about 10 % of myelinated fibers were destructively changed. In series 2, the numerical density of the endoneural vessels of the tibial nerve was doubled in comparison with the intact one; the numerical and dimensional composition of the regenerated myelinated fibers indicated active but incomplete regeneration. The vascularization index of the plantar interosseous muscles in series 1 was close to normal, in series 2 it decreased twice, the median of muscle fiber diameters was reduced by 12.41 % (p = 0.000) and 20.96 % (p = 0.000), respectively. Muscle fibers with a diameter of more than 30 μm increased in series 2 compared to series 1. Conclusion Internal neurolysis and interfascicular autoplasty of the sciatic nerve cause multidirectional changes in the endoneural vessels of the tibial nerve, which predetermine the multidirectional nature and severity of denervation and reinnervation changes in the nerves of the lower leg and small muscles of the foot.

Clinical, electrophysiological, and imaging findings in childhood brachial plexus injury.

AimTo assess the prognostic capabilities of various diagnostic modalities for childhood brachial plexus injuries (BPIs) and brachial plexus birth injury (BPBI) and postneonatal BPI.MethodIn this single‐center retrospective cross‐sectional study, we examined children with BPIs diagnosed or confirmed by electrodiagnostic studies between 2013 and 2020, and compared the prognostic value of various components of the electrophysiologic findings, magnetic resonance imaging (MRI) data, and the Active Movement Scale (AMS). We developed scoring systems for electrodiagnostic studies and MRI findings, including various components of nerve conduction studies and electromyography (EMG) for electrodiagnostic studies.ResultsWe identified 21 children (10 females and 11 males) aged 8 days to 21 years (mean 8y 6.95mo) who had a total of 30 electrodiagnostic studies, 14 brachial plexus MRI studies, and 10 surgical procedures. Among the diagnostic modalities assessed, brachial plexus MRI scores, EMG denervation scores, and mean total EMG scores were the most valuable in predicting surgical versus non‐surgical outcomes. Correspondingly, a combined MRI/mean total EMG score provided prognostic value.InterpretationBrachial plexus MRI scores and specific electrodiagnostic scores provide the most accurate prognostic information for children with BPI. Our grading scales can assist a multidisciplinary team in quantifying results of these studies and determining prognosis in this setting.What this paper adds A new scoring system to quantify results of electrodiagnostic and magnetic resonance imaging (MRI) studies is presented.Severity of denervation has good prognostic value for childhood brachial plexus injuries (BPIs).Composite electromyography scores have good prognostic value for childhood BPIs.Brachial plexus MRI has good prognostic value for childhood BPIs.

Whole blood survival motor neuron protein levels correlate with severity of denervation in spinal muscular atrophy.

IntroductionWe sought to determine whether survival motor neuron (SMN) protein blood levels correlate with denervation and SMN2 copies in spinal muscular atrophy (SMA).MethodsUsing a mixed‐effect model, we tested associations between SMN levels, compound muscle action potential (CMAP), and SMN2 copies in a cohort of 74 patients with SMA. We analyzed a subset of 19 of these patients plus four additional patients who had been treated with received gene therapy to examine SMN trajectories early in life.ResultsPatients with SMA who had lower CMAP values had lower circulating SMN levels (P = .04). Survival motor neuron protein levels were different between patients with two and three SMN2 copies (P < .0001) and between symptomatic and presymptomatic patients (P < .0001), with the highest levels after birth and progressive decline over the first 3 years. Neither nusinersen nor gene therapy clearly altered SMN levels.DiscussionThese data provide evidence that whole blood SMN levels correlate with SMN2 copy number and severity of denervation.

What influences contracture formation in lower motor neuron disorders, severity of denervation or residual muscle function? An analysis of the elbow contracture in 100 children with unilateral Brachial Plexus Birth Injury.

:PurposeAs in other neuromuscular disorders, both denervation and muscle paresis/imbalance are implicated as aetiological factors for contractures in children with a Brachial Plexus Birth Injury (BPBI). Although both factors are related, it is unclear which factor is dominant. The aim of this study is to assess whether contracture formation in children is predominantly related to denervation or to residual muscle function/imbalance. This might be relevant for understanding contracture formation in other neuromuscular disorders.MethodsA total of 100 children (61 boys; mean age 10.4 years, 4 to 18) with unilateral BPBI were included in this cross-sectional study. Severity of the denervation was classified according to Narakas. Muscle function of flexors and extensors of both elbows was measured (in Newtons) using a hand-held dynamometer and flexion contractures were measured with a goniometer. The relation between denervation, muscle function/muscle balance and flexion contracture was assessed using univariate and multivariate analysis.ResultsOf the children, 57 were Narakas class I, 13 class II and 30 class III. Mean flexion contracture was 25° (90° to −5°). At the affected side the forearm flexion force was 47% and extension force was 67% of the force of the unaffected side. Contractures were more severe in children with higher Narakas classifications (p = 0.001), after neurosurgery (Mann-Whitney U test, p = 0.009) and were related to age (Spearman’s Rho = −0.3, p = 0.008) and to paresis of the extensors (Rho = 0.4, p = 0.000). Flexor paresis as a percentage of unaffected side (Rho = 0.06, p = 0.6) and muscle balance had no influence.ConclusionIn BPBI, elbow contractures are related to the severity of the neurological lesion, not to residual muscle function.Level of evidenceLevel II – prognostic study

Relationship among nigrostriatal denervation, parkinsonism, and dyskinesias in the MPTP primate model

Presynaptic denervation is likely to play an important role in the pathophysiology of dyskinesias that develop after levodopa administration to patients with Parkinson's disease. In this study, the thresholds of nigrostriatal damage necessary for the occurrence of parkinsonism and levodopa-induced involuntary movements were compared in squirrel monkeys lesioned with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Animals treated with a regimen of MPTP that caused parkinsonism displayed > or =95% striatal dopamine depletion, 90% reduction of striatal dopamine uptake sites, and 70% nigral neuronal loss. Levodopa administration ameliorated the parkinsonian signs of these monkeys but also induced dyskinesias. A separate group of animals was treated with a milder MPTP regimen that caused 60%-70% striatal dopamine depletion, a 50% decrease in dopamine transporter, and 40% loss of dopaminergic nigral neurons. While these monkeys displayed no behavioral signs of parkinsonism, they all became dyskinetic after levodopa administration. The priming effect of levodopa, that is, the recurrence of dyskinesias in animals previously exposed to the drug, was compared in severely versus mildly lesioned monkeys. When severely injured parkinsonian animals underwent a second cycle of levodopa treatment, they immediately and consistently developed involuntary movements. In contrast, the recurrence of dyskinesias in primed monkeys with a partial nigrostriatal lesion required several levodopa administrations and remained relatively sporadic. The data indicate that moderate nigrostriatal damage which does not induce clinical parkinsonism predisposes to levodopa-induced dyskinesias. Once dyskinesias have been induced, the severity of denervation may enhance the sensitivity to subsequent levodopa exposures.