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1.
Neuron ; 108(1): 128-144.e9, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-32810432

RESUMO

Primary somatosensory neurons are specialized to transmit specific types of sensory information through differences in cell size, myelination, and the expression of distinct receptors and ion channels, which together define their transcriptional and functional identity. By profiling sensory ganglia at single-cell resolution, we find that all somatosensory neuronal subtypes undergo a similar transcriptional response to peripheral nerve injury that both promotes axonal regeneration and suppresses cell identity. This transcriptional reprogramming, which is not observed in non-neuronal cells, resolves over a similar time course as target reinnervation and is associated with the restoration of original cell identity. Injury-induced transcriptional reprogramming requires ATF3, a transcription factor that is induced rapidly after injury and necessary for axonal regeneration and functional recovery. Our findings suggest that transcription factors induced early after peripheral nerve injury confer the cellular plasticity required for sensory neurons to transform into a regenerative state.


Assuntos
Fator 3 Ativador da Transcrição/genética , Reprogramação Celular/genética , Gânglios Espinais/citologia , Regulação da Expressão Gênica/genética , Neuralgia/genética , Traumatismos dos Nervos Periféricos/genética , Células Receptoras Sensoriais/metabolismo , Animais , Axônios , Axotomia , Lesões por Esmagamento/genética , Lesões por Esmagamento/metabolismo , Vértebras Lombares , Mecanorreceptores/metabolismo , Camundongos , Regeneração Nervosa , Plasticidade Neuronal/genética , Nociceptores/metabolismo , RNA-Seq , Recuperação de Função Fisiológica , Nervo Isquiático/lesões , Nervo Isquiático/cirurgia , Análise de Célula Única , Nervos Espinhais/lesões , Nervos Espinhais/cirurgia , Transcriptoma
2.
Eur. j. anat ; 24(4): 281-284, jul. 2020. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-193961

RESUMO

Severe hamstring injuries warranting surgical repair are rare and mainly affect athletes, young and middle-aged people. A minority of these patients report postoperative complications of denervation. Symptoms of denervation range from muscle weakness to sciatic nerve palsy. Recent anatomical observations suggest that a recurrent motor nerve, which inserts into the proximal ham-strings, may be responsible for this denervation. The recurrent motor nerve was identified through cadaveric dissection and the site of nerve penetration into the muscle, measured 1.5 cm from the ischial tuberosity. This distance is significantly shorter than previous studies report. Awareness of this nerve branch is an important consideration in hamstring injury and repair. Due to its course, the recurrent motor nerve’s name is also a source of discussion


No disponible


Assuntos
Humanos , Nervo Isquiático/anatomia & histologia , Denervação/métodos , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/inervação , Cadáver , Nervo Isquiático/patologia , Nervo Isquiático/cirurgia , Nervos Periféricos/anatomia & histologia
3.
Acta Orthop Traumatol Turc ; 54(3): 330-336, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32544069

RESUMO

OBJECTIVE: The aim of this study was to compare the outcomes of primary nerve repair using either ethyl-cyanoacrylate or conventional microsuture technique in a rat peripheral nerve injury model. METHODS: In this study, a total of 30 Wistar Albino rats weighing between 220 and 275 g were used. The rats were randomly divided into three groups (10 in each), including one control (group 1) and two experimental groups (group 2, conventional microsuture repair; group 3, cyanoacrylate repair). In each group, the sciatic nerve was identified and transected. No further intervention was performed in group 1. The nerve was repaired using the epineural technique with a 10/0 atraumatic nylon in group 2 and synthetic cyanoacrylate adhesive in group 3. At the fifth postoperative week, needle electromyography (EMG) was performed to measure distal latency, combined muscle action potential (CMAP), and motor nerve conduction velocity (MNCV). Following the EMG recordings, animals were euthanized. Nerve samples were collected to evaluate vacuolar degeneration, fibrosis, and foreign body reaction histopathologically. RESULTS: In the EMG analysis, mean distal latency was significantly shorter in group 1 (0.85±0.09 ms) than in groups 2 (1.17±0.25 ms) (p=0.0052) and 3 (1.14±0.14 ms) (p=0.0026) while no significant differences existed between groups 2 and 3 (p>0.9999). The mean CMAP was greater in group 1 (10.5±0.35 mV) than in groups 2 (2.86±1.28 mV) (p=0.011) and 3 (2.16±1.34 mV) (p=0.0002), but there was no significant difference between groups 2 and 3 (p>0.9999). The mean MNCV was 53.5±5.95, 39.62±7.31, and 39.84±4.73 mm/sec in groups 1, 2, and 3, respectively. There was a significant difference between groups 1 and 2 (p=0.0052) and between 1 and 3 (p=0.0026), but not between 2 and 3 (p>0.9999). In the histopathological evaluation, the mean vacuolar degeneration score was 0, 2.12, and 1.88 in groups 1, 2, and 3, respectively. No obvious difference was observed between groups 2 and 3 (p=0.743). The mean fibrosis score was 0, 1.62, and 1.77 in groups 1, 2, and 3, respectively. There was no significant difference between groups 2 and 3 (p=0.888). The mean foreign body reaction score was 0, 2.5, and 2.44 in groups 1, 2, and 3, respectively. No difference was present between groups 2 and 3 (p=0.743). CONCLUSION: Primary nerve repair using the cyanoacrylate adhesive may provide similar electrophysiological and histopathological results as compared to the conventional microsuture repair.


Assuntos
Cianoacrilatos/farmacologia , Procedimentos Neurocirúrgicos/métodos , Traumatismos dos Nervos Periféricos/cirurgia , Nervo Isquiático , Procedimentos Cirúrgicos sem Sutura/métodos , Animais , Eletromiografia/métodos , Masculino , Regeneração Nervosa , Traumatismos dos Nervos Periféricos/diagnóstico , Ratos , Ratos Wistar , Nervo Isquiático/lesões , Nervo Isquiático/cirurgia , Técnicas de Sutura , Adesivos Teciduais/farmacologia , Resultado do Tratamento
4.
Acta Cir Bras ; 35(4): e202000405, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555937

RESUMO

PURPOSE: To investigate the effects of Chemically Extracted Acellular Nerves (CEANs) when combined with Adipose-Derived mesenchymal Stem Cell (ADSC) transplantation on the repair of sciatic nerve defects in rabbits. METHODS: A total of 71 six-month-old Japanese rabbit were used in this study. Twenty rabbits served as sciatic nerve donors, while the other 51 rabbits were randomly divided into Autologous Nerve Transplantation Group (ANT, n=17), CEAN group (n=17) and CEAN-ADSCs group (n=17). In all these groups, the rabbit's left sciatic nerves were injured before the experiment, and the uninjured sciatic nerves on their right side were used as the control (CON). Electrophysiological tests were carried out and sciatic nerves were prepared for histomorphology and stretch testing at 24 weeks post-transplant. RESULTS: There were significant differences between ANT and Con groups in amplitude (AMP): P=0.031; motor nerve conduction velocity (MNCV): P=0.029; Maximum stress: P=0.029; and Maximum strain P=0.027. There were also differences between the CEAN and CEAN+ADSCs groups in AMP: P=0.026, MNCV: P=0.024; Maximum stress: P=0.025 and Maximum strain: P=0.030. No significant differences in these parameters were observed when comparing the ANT and CEAN+SACN groups (MNCV: P=0.071) or the CEAN and ANT groups (Maximum stress: P=0.069; Maximum strain P=0.077). CONCLUSION: Addition of ADSCs has a significant impact on the recovery of nerve function, morphology, and tensile mechanical properties following sciatic nerve injury.


Assuntos
Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais , Tecido Nervoso/transplante , Neuropatia Ciática/fisiopatologia , Neuropatia Ciática/cirurgia , Animais , Fenômenos Biomecânicos , Eletromiografia , Masculino , Regeneração Nervosa/fisiologia , Tecido Nervoso/citologia , Coelhos , Valores de Referência , Reprodutibilidade dos Testes , Nervo Isquiático/fisiopatologia , Nervo Isquiático/cirurgia , Resultado do Tratamento
6.
PLoS One ; 15(5): e0233531, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32453807

RESUMO

Several studies have investigated the use of invasive and non-invasive stimulation methods to enhance nerve regeneration, and varying degrees of effectiveness have been reported. However, due to the use of different parameters in these studies, a fair comparison between the effectiveness of invasive and non-invasive stimulation methods is not possible. The present study compared the effectiveness of invasive and non-invasive stimulation using similar parameters. Eighteen Sprague Dawley rats were classified into three groups: the iES group stimulated with fully implantable device, the tES group stimulated with transcutaneous electrical nerve stimulation (TENS), and the injury group (no stimulation). The iES and tES groups received stimulation for 6 weeks starting immediately after the injury. Motor function was evaluated using the sciatic functional index (SFI) every week. The SFI values increased over time in all groups; faster and superior functional recovery was observed in the iES group than in the tES group. Histological evaluation of the nerve sections and gastrocnemius muscle sections were performed every other week. The axon diameter and muscle fiber area in the iES group were larger, and the g-ratio in the iES group was closer to 0.6 than those in the tES group. To assess the cause of the difference in efficiency, a 3D rat anatomical model was used to simulate the induced electric fields in each group. A significantly higher concentration and intensity around the sciatic nerve was observed in the iES group than in the tES group. Vector field distribution showed that the field was orthogonal to the sciatic nerve spread in the tES group, whereas it was parallel in the iES group; this suggested that the tES group was less effective in nerve stimulation. The results indicated that even though rats in the TENS group showed better recovery than those in the injury group, it cannot replace direct stimulation yet because rats stimulated with the invasive method showed faster recovery and superior outcomes. This was likely attributable to the greater concentration and parallel distribution of electric field with respect to target nerve.


Assuntos
Lesões por Esmagamento/terapia , Regeneração Nervosa/fisiologia , Neuropatia Ciática/terapia , Estimulação Elétrica Nervosa Transcutânea , Animais , Axônios/efeitos da radiação , Lesões por Esmagamento/fisiopatologia , Lesões por Esmagamento/cirurgia , Modelos Animais de Doenças , Humanos , Fibras Musculares Esqueléticas/fisiologia , Fibras Musculares Esqueléticas/efeitos da radiação , Músculo Esquelético/fisiopatologia , Músculo Esquelético/efeitos da radiação , Compressão Nervosa/métodos , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica/fisiologia , Nervo Isquiático/crescimento & desenvolvimento , Nervo Isquiático/fisiopatologia , Nervo Isquiático/cirurgia , Neuropatia Ciática/fisiopatologia , Neuropatia Ciática/cirurgia
7.
Ulus Travma Acil Cerrahi Derg ; 26(3): 361-365, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32436974

RESUMO

BACKGROUND: The debate continues concerning surgical timing in a peripheral nerve injury. This study aims to evaluate the result of immediate versus delayed primary (after seven days) repair of peripheral nerve injury. METHODS: In this study, Wistar rats were divided into four groups as follows: The nerve was sharply transected in Group 1, 2 and 4. It was immediately sutured in Group 1 and sutured seven days later in Group 2, and it was not sutured in Group 4. In Group 3, the left sciatic nerve was only explored. Eight weeks later, tissue samples were extracted from the injured nerve area. Both gastrocnemius muscles were weighed. The nerve samples were examined for axon degeneration. Myelin vacuolization, axon irregularity, and edema/inflammation parameters were evaluated. RESULTS: There were not any significant differences in the score of axon degeneration and the weight of the gastrocnemius muscle between the immediate and delayed primary repair groups. However, these parameters were significantly better in both repair groups than to be in the control group and significantly worse than to be in the sham-operated group. CONCLUSION: To delay the repair about one week did not affect the histological results and weight of the muscle that was innervated by the sectioned nerve comparing to be in the immediate repair in a sciatic nerve transaction model in rats.


Assuntos
Procedimentos Neurocirúrgicos , Traumatismos dos Nervos Periféricos/cirurgia , Nervo Isquiático , Animais , Modelos Animais de Doenças , Ratos , Ratos Wistar , Nervo Isquiático/lesões , Nervo Isquiático/cirurgia , Tempo para o Tratamento
8.
World Neurosurg ; 140: 4-9, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32407922

RESUMO

BACKGROUND: Adipose lesions of nerve are generally distinguished as either extraneural or intraneural lipomas or, alternatively, lipomatosis of nerve. We present a patient with an unusual circumferential lipoma that completely encircles the right sciatic nerve and discuss a possible pathogenesis. CASE DESCRIPTION: A 44-year-old woman presented with progressive symptoms and signs of sciatic neuropathy for 1 year. Magnetic resonance imaging revealed a large lipomatous mass extending from the level of the lesser trochanter to the distal third of the femur. The sciatic nerve was completely enveloped by the lipoma in the proximal segment, partially enveloped in the mid-segment and was separate from the nerve in the distal segment. The lipoma was not covered by the epineurium. The tumor was completely resected and the patient's neurologic symptoms improved. CONCLUSIONS: The pathogenetic mechanism of the reported circumferential lipoma of the sciatic nerve is not known. Two possible mechanisms considered included 1) envelopment by an extraneural lipoma over time and 2) occurrence of a lipoma in the paraneurial compartment (and in this case, extension into an extraneural one). Based on the available literature, lipomas that circumferentially envelop the entire nerve seem to be underrecognized and poorly understood. Analogous cases of lipomas enveloping nerves or other structures than nerves have been reported in the literature. Our reported case highlights the complexity of adipose lesions affecting nerves.


Assuntos
Lipoma/patologia , Nervo Isquiático/patologia , Adulto , Feminino , Humanos , Lipoma/cirurgia , Nervo Isquiático/cirurgia
9.
Am J Physiol Cell Physiol ; 318(6): C1154-C1165, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32233950

RESUMO

Homeobox A9 (HOXA9), the expression of which is promoted by mixed lineage leukemia 1 (MLL1) and WD-40 repeat protein 5 (WDR5), is a homeodomain-containing transcription factor that plays an essential role in regulating stem cell activity. HOXA9 has been found to inhibit skeletal muscle regeneration and delay recovery after muscle wounding in aged mice, but little is known about its role in denervated/reinnervated muscles. We performed detailed time-dependent expression analyses of HOXA9 and its promoters, MLL1 and WDR5, in rat gastrocnemius muscles after the following three types of sciatic nerve surgeries: nerve transection (denervation), end-to-end repair (repair), and sham operation (sham). Then, the specific mechanisms of HOXA9 were detected in vitro by transfecting primary satellite cells with empty pIRES2-DsRed2, pIRES2-DsRed2-HOXA9, empty pPLK/GFP-Puro, and pPLK/GFP-Puro-HOXA9 small hairpin RNA (shRNA) plasmids. We found, for the first time, that HOXA9 protein expression simultaneously increased with increasing denervated muscle atrophy severity and that upregulated MLL1 and WDR5 expression was partly associated with denervation. Indeed, in vitro experiments revealed that HOXA9 inhibited myogenic differentiation, affected the best known atrophic signaling pathways, and promoted apoptosis but did not eliminate the differentiation potential of primary satellite cells. HOXA9 may promote denervated muscle atrophy by regulating the activity of satellite cells.


Assuntos
Proteínas de Homeodomínio/metabolismo , Desenvolvimento Muscular , Músculo Esquelético/inervação , Atrofia Muscular/metabolismo , Regeneração Nervosa , Células Satélites de Músculo Esquelético/metabolismo , Nervo Isquiático/cirurgia , Animais , Animais Recém-Nascidos , Apoptose , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Regulação da Expressão Gênica , Membro Posterior , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Proteínas de Homeodomínio/genética , Masculino , Denervação Muscular , Atrofia Muscular/genética , Atrofia Muscular/patologia , Atrofia Muscular/fisiopatologia , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Ratos Sprague-Dawley , Células Satélites de Músculo Esquelético/patologia , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia , Transdução de Sinais , Fatores de Tempo
10.
Plast Reconstr Surg ; 145(4): 949-956, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32221212

RESUMO

BACKGROUND: Nerve regeneration after an injury should occur in a timely fashion for function to be restored. Current methods cannot monitor regeneration prior to muscle reinnervation. Diffusion tensor imaging has been previously shown to provide quantitative indices after nerve recovery. The goal of this study was to validate the use of this technology following nerve injury via a series of rat sciatic nerve injury/repair studies. METHODS: Sprague-Dawley rats were prospectively divided by procedure (sham, crush, or cut/repair) and time points (1, 2, 4, and 12 weeks after surgery). At the appropriate time point, each animal was euthanized and the sciatic nerve was harvested and fixed. Data were obtained using a 7-Tesla magnetic resonance imaging system. For validation, findings were compared to behavioral testing (foot fault asymmetry and sciatic function index) and cross-sectional axonal counting of toluidine blue-stained sections examined under light microscopy. RESULTS: Sixty-three rats were divided into three treatment groups (sham, n = 21; crush, n = 23; and cut/repair, n = 19). Fractional anisotropy was able to differentiate between recovery following sham, crush, and cut/repair injuries as early as 2 weeks (p < 0.05), with more accurate differentiation thereafter. More importantly, the difference in anisotropy between distal and proximal regions recognized animals with successful and failed recoveries according to behavioral analysis, especially at 12 weeks. In addition, diffusion tension imaging-based tractography provided a visual representation of nerve continuity in all treatment groups. CONCLUSIONS: Diffuse tensor imaging is an objective and noninvasive tool for monitoring nerve regeneration. Its use could facilitate earlier detection of failed repairs to potentially help improve outcomes.


Assuntos
Imagem de Tensor de Difusão/métodos , Nervo Isquiático/lesões , Animais , Lesões por Esmagamento/fisiopatologia , Lesões por Esmagamento/cirurgia , Modelos Animais de Doenças , Masculino , Regeneração Nervosa/fisiologia , Ratos Sprague-Dawley , Recuperação de Função Fisiológica/fisiologia , Nervo Isquiático/fisiologia , Nervo Isquiático/cirurgia
11.
Biomater Sci ; 8(3): 798-811, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31904045

RESUMO

In this work, dextran-based nerve tube-guides were prepared, characterized and used in a standardized animal model of neurotmesis injury. Non-porous and porous transparent tube-guides were obtained by photocrosslinking of two co-macromonomers based on dextran and poly(ε-caprolactone) (PCL). Swelling capacity of the tube-guides ranged from 40-60% with no visible constriction of their inner diameter. In vitro hydrolytic degradation tests showed that the tube-guides maintained their structural integrity up to 6 months. The in vivo performance of the tube-guides was evaluated by entubulation of the rat sciatic nerve after a neurotmesis injury, with a 10 mm-gap between the nerve stumps. The results showed that the tube-guides were able to promote the regeneration of the nerve in a similar manner to what was observed with conventional techniques (nerve graft and end-to-end suture). Stereological analysis proved that nerve regeneration occurred, and both tube-guides presented fibre diameter and g-ratio closer to healthy sciatic nerves. The histomorphometric analysis of Tibialis anterior (TA) skeletal muscle showed decreased neurogenic atrophy in the porous tube-guides treated group, presenting measurements that are similar to the uninjured control.


Assuntos
Dextranos/química , Regeneração Tecidual Guiada/métodos , Nervo Isquiático/lesões , Nervo Isquiático/fisiopatologia , Traumatismos do Sistema Nervoso/fisiopatologia , Animais , Materiais Biocompatíveis/química , Caproatos , Regeneração Tecidual Guiada/instrumentação , Lactonas , Masculino , Regeneração Nervosa , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/cirurgia , Traumatismos do Sistema Nervoso/cirurgia
12.
Anesthesiology ; 132(4): 854-866, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31996555

RESUMO

BACKGROUND: The basic perineural catheter design has changed minimally since inception, with the catheter introduced through or over a straight needle. The U.S. Food and Drug Administration recently cleared a novel perineural catheter design comprising a catheter attached to the back of a suture-shaped needle that is inserted, advanced along the arc of its curvature pulling the catheter past the target nerve, and then exited through the skin in a second location. The authors hypothesized that analgesia would be noninferior using the new versus traditional catheter design in the first two days after painful foot/ankle surgery with a primary outcome of average pain measured with the Numeric Rating Scale. METHODS: Subjects undergoing painful foot or ankle surgery with a continuous supraparaneural popliteal-sciatic nerve block 5 cm proximal to the bifurcation were randomized to either a suture-type or through-the-needle catheter and subsequent 3-day 0.2% ropivacaine infusion (basal 6 ml/h, bolus 4 ml, lockout 30 min). Subjects received daily follow-up for the first four days after surgery, including assessment for evidence of malfunction or dislodgement of the catheters. RESULTS: During the first two postoperative days the mean ± SD average pain scores were lower in subjects with the suture-catheter (n = 35) compared with the through-the-needle (n = 35) group (2.7 ± 2.4 vs. 3.4 ± 2.4) and found to be statistically noninferior (95% CI, -1.9 to 0.6; P < 0.001). No suture-style catheter was completely dislodged (0%), whereas the tips of three (9%) traditional catheters were found outside of the skin before purposeful removal on postoperative day 3 (P = 0.239). CONCLUSIONS: Suture-type perineural catheters provided noninferior analgesia compared with traditional catheters for continuous popliteal-sciatic blocks after painful foot and ankle surgery. The new catheter design appears to be a viable alternative to traditional designs used for the past seven decades.


Assuntos
Anestesia por Condução/métodos , Bloqueio Nervoso Autônomo/métodos , Cateteres de Demora , Dor Pós-Operatória/prevenção & controle , Nervo Isquiático/diagnóstico por imagem , Técnicas de Sutura , Adulto , Idoso , Anestésicos Locais/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor/efeitos dos fármacos , Medição da Dor/métodos , Dor Pós-Operatória/diagnóstico por imagem , Nervo Isquiático/cirurgia , Ultrassonografia de Intervenção/métodos
13.
World Neurosurg ; 133: e288-e292, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31518736

RESUMO

OBJECTIVE: We sought to elucidate the conditions of direct suturing of sciatic nerve defects in high-degree knee flexion. We aimed to establish a correlation among the defect length, defect location, degree of knee flexion, and eventual need for hip immobilization in extension. METHODS: We performed an experimental study by completing bilateral dissection of the sciatic nerve in 6 cadavers. Three groups of lesions were identified: at the buttock (BG), in the thigh (TG), and in the popliteal fossa (PG). For each defect, a direct, tensionless suture was performed with minimal knee flexion. Next, the hip was progressively flexed until rupture. The nerve defect length correlated with the degree of knee flexion and hip extension required to perform and protect the installed sutures. RESULTS: A 30° knee flexion allowed for direct suturing of defects >2 cm in the 3 groups. The largest suturable nerve defects measured 7 cm in the TG and PG and 6 cm in the BG. When considering the same-size defects, the required knee flexion tended to be significantly greater in the BG. A bowstringing effect was noted at the buttock and popliteal levels. Hip flexion placed tension on the nerve suture at all locations. CONCLUSIONS: The middle third of the thigh was the most compliant level, because the largest defects will be suturable without a visible bowstringing effect. Hip immobilization should be considered as soon as the defect has exceeded 2 cm, regardless of the location.


Assuntos
Joelho/fisiologia , Nervo Isquiático/cirurgia , Técnicas de Sutura , Antropometria , Cadáver , Feminino , Humanos , Imobilização , Masculino , Movimento (Física)
14.
J Bone Joint Surg Am ; 102(3): 245-253, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31609892

RESUMO

BACKGROUND: For peripheral nerve defects, autografting is considered the therapeutic gold-standard treatment. However, this procedure leads to donor-site morbidity. While various artificial conduits have been recently developed, treatment outcome has been demonstrated to be poorer than that with autograft. In our previous study using a rat sciatic nerve crush injury model, we demonstrated that the delivery of electrospun nanofiber sheets incorporating methylcobalamin (MeCbl sheet) to the local site of a peripheral nerve injury promoted peripheral nerve regeneration. In this study, we examined the effects of combination therapy using an MeCbl sheet and a polyglycolic acid tube filled with collagen sponge (PGA-c) in a rat model of a 10-mm sciatic nerve defect. METHODS: The rats were divided into 4 groups: (1) sham group (n = 10); (2) PGA-c group (n = 9), in which the gap was bridged using a PGA-c; (3) PGA-c/Sheet group (n = 8), in which the gap was bridged using a PGA-c wrapped in an MeCbl sheet; and (4) autograft group (n = 10), in which the gap was bridged using a reversed autograft. Motor and sensory function were evaluated, electrophysiological analysis was performed, and histomorphological findings were analyzed at 12 weeks postoperatively. RESULTS: Compared with the PGA-c group, the PGA-c/Sheet group demonstrated significant improvements in the paw-withdrawal threshold expressed as a ratio relative to the contralateral side (mean difference [MD], -1.51; 95% confidence interval [CI], -2.64 to -0.38), terminal latency (MD, -0.86 ms; 95% CI, -1.56 to -0.16 ms), myelinated axon area (MD, 4.97%; 95% CI, 0.14% to 9.80%), proportion of myelinated axons (MD, 8.453%; 95% CI, 0.001% to 16.905%), and g-ratio (MD, -0.018; 95% CI, -0.035 to -0.001). No significant improvements were observed regarding motor function, electrophysiological findings with the exception of terminal latency, and axon numbers. CONCLUSIONS: An MeCbl sheet in combination with a PGA-c significantly accelerated recovery with respect to sensory function, electrophysiology, and histomorphometry. CLINICAL RELEVANCE: An MeCbl sheet may represent an effective therapeutic strategy for promoting regeneration across a nerve gap bridged with an artificial conduit.


Assuntos
Colágeno/uso terapêutico , Regeneração Tecidual Guiada/métodos , Nanofibras/uso terapêutico , Regeneração Nervosa/fisiologia , Traumatismos dos Nervos Periféricos/cirurgia , Ácido Poliglicólico/uso terapêutico , Nervo Isquiático , Vitamina B 12/análogos & derivados , Implantes Absorvíveis , Animais , Axônios/fisiologia , Modelos Animais de Doenças , Masculino , Atividade Motora/fisiologia , Traumatismos dos Nervos Periféricos/fisiopatologia , Ratos , Nervo Isquiático/lesões , Nervo Isquiático/cirurgia , Vitamina B 12/uso terapêutico
15.
J Cardiovasc Surg (Torino) ; 61(4): 467-470, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30917649

RESUMO

BACKGROUND: Neuropathic pain often occurs after leg amputation. It is unclear why some patients suffer from pain and others do not. Intraoperative nerve handling might correlate with these pain syndromes. It is unknown which nerve handling techniques are currently used among surgeons and whether a specific technique is related to eliciting these pain syndromes. The aim of this study was to investigate the current surgical sciatic nerve management used among surgeons in the Netherlands. METHODS: A survey was carried out among Dutch surgeons. Additionally, surgical sciatic nerve management data were obtained from the surgical reports of transfemoral amputations that were performed in our hospital. RESULTS: Seventy-eight of the 102 online surveys were returned. Sharp transection without ligation was used most often (41.0%), followed by sharp transection after ligation (30.8%). There were 38 transfemoral amputations performed in our hospital. Sharp transection after ligation was most often used (55.3%), followed by transection with electrocautery (13.2%). CONCLUSIONS: All techniques of transecting the sciatic nerve are currently performed by Dutch surgeons. These results provide a solid basis to perform future studies to investigate whether a specific surgical technique is related to postamputation pain syndromes.


Assuntos
Amputação , Perna (Membro)/cirurgia , Neuralgia/etiologia , Neuralgia/prevenção & controle , Padrões de Prática Médica/estatística & dados numéricos , Nervo Isquiático/cirurgia , Adulto , Idoso , Eletrocoagulação , Feminino , Humanos , Ligadura , Masculino , Pessoa de Meia-Idade , Países Baixos , Inquéritos e Questionários
16.
J Plast Reconstr Aesthet Surg ; 73(2): 214-221, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31690543

RESUMO

The authors hypothesize that a fascicular turnover flap will achieve better nerve regeneration in nerve gap repair than a conventional nerve graft in a rat sciatic nerve defect model. Seven-millimeter-long sciatic nerve defects were repaired with an autologous nerve graft, a proximal fascicular turnover flap, or a distal fascicular turnover flap. Following walking footprint analysis 8 weeks after the surgery, the gastrocnemius-soleus muscles of the hind limbs, nerve graft, and flaps were harvested for wet muscle weight assessment, immunohistochemistry, and transmission electron microscopy. The distal fascicular turnover flap exhibited improvement in the sciatic function index similar as that observed for the autologous nerve graft. Histologically, cross sections showed a higher staining intensity for S-100 in the distal fascicular turnover flap group than for S-100 in the nerve graft group (p = 0.01). In the longitudinal sections, the staining intensity for NF-200 was higher in the distal fascicular turnover flap group than in the nerve graft (p = 0.009) and proximal fascicular turnover flap (p = 0.004) groups. More mature capillaries were observed in the proximal (p < 0.001) and distal (p = 0.029) fascicular turnover flap groups than in the nerve graft group. Transmission electron microscopy results showed a compact, regular myelin sheath around the myelinated nerve fibers in the distal fascicular turnover flap group, unlike observations in the nerve graft and proximal fascicular turnover flap groups. This study demonstrates better nerve regeneration in nerve gap repair with the distal fascicular turnover flap than with the conventional nerve graft.


Assuntos
Regeneração Nervosa , Nervo Isquiático/fisiologia , Nervo Isquiático/cirurgia , Retalhos Cirúrgicos , Animais , Autoenxertos , Masculino , Modelos Animais , Procedimentos Neurocirúrgicos/métodos , Ratos , Ratos Sprague-Dawley
17.
Pain Pract ; 20(1): 75-87, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31424152

RESUMO

BACKGROUND: Experimental and clinical studies have shown that tonic spinal cord stimulation (SCS) releases gamma-aminobutyric acid (GABA) in the spinal dorsal horn. Recently, it was suggested that burst SCS does not act via spinal GABAergic mechanisms. Therefore, we studied spinal GABA release during burst and tonic SCS, both anatomically and pharmacologically, in a well-established chronic neuropathic pain model. METHODS: Animals underwent partial sciatic nerve ligation (PSNL). Quantitative immunohistochemical (IHC) analysis of intracellular GABA levels in the lumbar L4 to L6 dorsal spinal cord was performed after 60 minutes of burst, tonic, or sham SCS in rats that had undergone PSNL (n = 16). In a second pharmacological experiment, the effects of intrathecal administration of the GABAA antagonist bicuculline (5 µg) and the GABAB antagonist phaclofen (5 µg) were assessed. Paw withdrawal thresholds to von Frey filaments of rats that had undergone PSNL (n = 20) were tested during 60 minutes of burst and tonic SCS 30 minutes after intrathecal administration of the drugs. RESULTS: Quantitative IHC analysis of GABA immunoreactivity in spinal dorsal horn sections of animals that had received burst SCS (n = 5) showed significantly lower intracellular GABA levels when compared to sham SCS sections (n = 4; P = 0.0201) and tonic SCS sections (n = 7; P = 0.0077). Intrathecal application of the GABAA antagonist bicuculline (5 µg; n = 10) or the GABAB antagonist phaclofen (5 µg; n = 10) resulted in ablation of the analgesic effect for both burst SCS and tonic SCS. CONCLUSIONS: In conclusion, our anatomical and pharmacological data demonstrate that, in this well-established chronic neuropathic animal model, the analgesic effects of both burst SCS and tonic SCS are mediated via spinal GABAergic mechanisms.


Assuntos
Neuralgia/metabolismo , Estimulação da Medula Espinal/métodos , Ácido gama-Aminobutírico/metabolismo , Animais , Modelos Animais de Doenças , Ligadura , Masculino , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/lesões , Nervo Isquiático/cirurgia
18.
Georgian Med News ; (309): 124-131, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33526741

RESUMO

Mechanical damage to the peripheral nerve is a fairly common type of injury, which is characterized by a complex of long-term neurological disorders and require significant financial costs. The aim of this work is to evaluate the efficiency of sciatic nerve (SN) regeneration after neuroraphy using epineural suture (ES), polyethylene glycol hydrogel (PEG), and fibrin glue (FG). The studies were carried out on 30 white outbred male rats, which were divided into six experimental groups: Group №1: intact rats; Group №2: Sham operated; Group №3: complete transection of the SN; Group №4: nerve repair with ES; Group №5: nerve repair with PEG; Group №6: nerve repair with FG. Functional recovery was assessed at 1, 2, 3, 4 postoperative weeks using a walking-track analysis with subsequent determination of the sciatic nerve functional index (SFI). At 4 weeks, electroneuromyography, histological and morphometric analyzes were performed. The combined analysis indicated that PEG significantly improved functional recovery, both in the SFI index and in the skeletal muscle M-response. Compared to ES and PEG, the use of FG was reflected in a lower significance of the indicators compared to PEG. Statistical analysis indicates a positive effect of PEG and FG on nerve regeneration, although significantly greater remyelination (analysis based on fiber diameter) was confirmed only in the PEG group, which explains the faster functional recovery of the limb. PEG in the form of a hydrogel is a more promising agent in microsurgical restoration of damaged nerves as an adhesive, it promotes rapid nerve regeneration, denervated muscle re-innervation and functional limb recovery.


Assuntos
Adesivo Tecidual de Fibrina , Nervo Isquiático , Hidrogéis , Masculino , Polietilenoglicóis , Nervo Isquiático/cirurgia , Suturas
19.
J Comput Assist Tomogr ; 43(6): 976-980, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31688247

RESUMO

Endometriosis (EN) is a common gynecological condition characterized by the presence of functional endometrium located outside the uterine cavity. Sciatic nerve (SN) is rarely affected by EN. Magnetic resonance imaging allows a direct visualization of the spinal and SN, and it is the modality of choice for the study of SN involvement in extrapelvic EN. We report a case of an endometrioma located in the right SN with a systematic review of the literature.


Assuntos
Endometriose/diagnóstico por imagem , Nervo Isquiático/patologia , Ciática/diagnóstico por imagem , Adulto , Endometriose/complicações , Endometriose/cirurgia , Feminino , Humanos , Laparoscopia , Imagem por Ressonância Magnética/métodos , Nervo Isquiático/diagnóstico por imagem , Nervo Isquiático/cirurgia , Ciática/etiologia , Ciática/cirurgia , Resultado do Tratamento
20.
Neuroscience ; 422: 134-145, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31682951

RESUMO

Schwann cells (SCs) combined with acellular nerve allografts (ANAs) effectively promote the regeneration and repair of peripheral nerves, but the exact mechanism has not been fully elucidated. However, the disadvantages of SCs include their limited source and slow rate of expansion in vitro. Previous studies have found that adipose-derived stem cells have the ability to differentiate into Schwann-like cells. Therefore, we speculated that Schwann-like cells combined with ANAs could profoundly facilitate nerve regeneration and repair. The aim of the present study was to investigate the cellular and molecular mechanisms of regeneration and repair. In this study, tissue-engineered nerves were first constructed by adipose-derived Schwann-like cells and ANAs to bridge missing sciatic nerves. Then, the rats were randomly divided into five groups (n = 12 per group): a Control group; a Model group; an ADSC group; an SC-L group; and a DMEM group. Twelve weeks postsurgery, behavioral function tests and molecular biological techniques were used to evaluate the function of regenerated nerves and the relevant molecular mechanisms after sciatic nerve injury (SNI). The results showed that adipose-derived Schwann-like cells combined with ANAs markedly promoted sciatic nerve regeneration and repair. These findings also demonstrated that the expression of neurotrophic factors (NFs) was increased, and the expression of Janus activated kinase2 (JAK2)/P-JAK2, signal transducer and activator of transcription-3 (STAT3)/P-STAT3 was decreased in the spinal cord after SNI. Therefore, these results suggested that highly expressed NFs in the spinal cord could promote nerve regeneration and repair by inhibiting activation of the JAK2/STAT3 signaling pathway.


Assuntos
Aloenxertos/transplante , Janus Quinase 2/fisiologia , Regeneração Nervosa/fisiologia , Fator de Transcrição STAT3/fisiologia , Nervo Isquiático/fisiopatologia , Animais , Fator Neurotrófico Derivado do Encéfalo/biossíntese , Fator Neurotrófico Ciliar/biossíntese , Masculino , Transplante de Células-Tronco Mesenquimais/métodos , Fator de Crescimento Neural/biossíntese , Neurônios/transplante , Ratos , Recuperação de Função Fisiológica/fisiologia , Nervo Isquiático/lesões , Nervo Isquiático/cirurgia , Transdução de Sinais/fisiologia , Medula Espinal/metabolismo
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