18 de jun de 2018

Sciatic Nerve Injection Palsy in a Dog: Electrodiagnostic Testing and Microsurgical Treatment

Acta Scientiae Veterinariae, 2018. 46(Suppl 1): 284.

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Ana Carolina Mortari , Juliany Gomes Quitzan , Claudia Valéria Seullner Brandão & Sheila Canevese Rahal

ABSTRACT 

Background: Iatrogenic damage to the ischiatic nerve is considered uncommon and may cause dysfunction with variable clinical signs dependent on type and severity of injury. Due to important role of this nerve in locomotion and weightbearing limb, a poor prognosis for recovery may be observed in many cases. Electromyography analysis may suggest the neuroanatomic localization, diagnosis information, and severity of lesion to determine better therapeutic intervention. Therefore, the aim of this report is to describe the possible cause, diagnosis and treatment of a postinjection ischiatic nerve injury in a dog with complete recovery. Case: A 3-year-old neutered male dachshund dog was referred to the Veterinary Hospital due to inability to weight support in the right hind limb after diminazene diaceturate intramuscular injection. The gait evaluation showed dropped-hock and knuckling into the digits of the right hind limb and neurologic examination revealed moderate muscle atrophy below to femorotibial joint of the right hind limb with sensory analgesia (superficial and deep) on the lateral, dorsal, and plantar surfaces, absent patellar reflex, and proprioceptive deficit. Electrophysiologic testing was done under general anesthesia in a 2-channel Nicolet Compass Meridian apparatus. Absence of compound muscle action potentials after right fibular and tibial nerve stimulations, and abnormal spontaneous activity in cranial tibial, gastrocnemius and deep digital extensor muscles were observed. A diagnosis of moderate/severe axonotmesis of sciatic nerve was achieved. Under microscope magnification, all adherent adjacent tissue and epineural sheat were removed. Due this, a small epineural window was created. On neurological examination performed 30 days after surgery, complete recovery of sensitivity of the right hind limb, and normal proprioception were observed. The muscle atrophy was also noted to have improved. Discussion: The ischiatic nerve mechanisms of injury include direct needle trauma, the drug or vehicle used for injection, or secondary constriction by scar, factors that may be associated to damage nerve observed in the present case. During a sciatic nerve injection, the combination of intrafascicular placement of a needle and high-pressure injection may cause severe fascicular damage and persistent neurologic deficits. In the present case, damage to the nerve probably was not caused by the injection needle, but due to injection agent. Chemical irritation or toxic reaction to the agent may cause different degrees of nerve injury. The electrophysiologic testing is an important tool for determining alteration of function and integrity of the axonal motor unit. In the present report, the electrophysiologic testing showed denervation potentials in the muscles innervated by the sciatic nerve (positive waves and fibrillation potentials), and the absence of compound muscle action potentials was indicative of severe axonal damage of the right ischiatic nerve. In human patients with postinjection ischiatic nerve injury, early surgical treatment with neurolysis or resection and anastomosis are the procedures recommended. In the present report, external neurolysis and epineural window were used showing excellent functional results. The epineural window was performed due to adherence of tissue and scar surrounding the nerve, permitting neural decompression.


14 de jun de 2018

Corpectomia lateral parcial para o tratamento de compressão ventral extradural crônica entre T9-T10 em um cão

Arq. Bras Med. Vet. Zootec., v.70, n.2, p.443-449, 2018

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P.V.T. Marinho , C.R.A. Ferrigno , T. Bregadioli , F. Paes2 , J.F. Santos , A.S. Macedo , Í.S. Dal-Bó, V.S. Galeazzi

 RESUMO Objetivou-se relatar um caso de protrusão do disco intervertebral com localização atípica e descrever a técnica cirúrgica de corpectomia lateral parcial no tratamento da afecção em um cão. Um cão de sete anos de idade, macho, raça Pug, foi atendido com ataxia proprioceptiva dos membros pélvicos havia três meses, associada à doença do disco intervertebral entre a nona e 10ª vértebras torácicas. Após um mês de tratamento conservativo sem melhora, o paciente foi encaminhado para o tratamento cirúrgico, quando foi realizada corpectomia lateral parcial esquerda para descompressão da medula espinhal. Após a cirurgia, o paciente apresentou melhora considerável do quadro, sendo a técnica eficaz na remoção da compressão extradural, sem manipulação da medula espinhal ou outras complicações.

Partial lateral corpectomy for treatment of chronic ventral extradural compression between T9-T10 in a dog

ABSTRACT The aim of this study is to report a case of intervertebral disc protrusion with atypical location and describe the surgical technique of partial lateral corpectomy in the treatment of this disease in a dog. A dog, seven -years-old, male, Pug breed was attended with proprioceptive ataxia of the hind limbs for three months correlated with intervertebral disc disease between the 9th and 10th thoracic vertebrae. After a month of conservative treatment without improvements, the patient was referred for surgical treatment, which was performed as a partial left lateral corpectomy for decompression of the spinal cord. After surgery, the patient showed considerable improvement, this technique being shown to be effective in the removal of extradural compression, without manipulation of the spinal cord or other complications. 

11 de jun de 2018

Índice de normalidade da distância atlantoaxial dorsal em cães

Arq. Bras. Med. Vet. Zootec., v.70, n.2, p.429-436, 2018

E.A. Tudury, A.C. Silva, M.A.S. Lacerda, B.M. Araújo, M.M.A. Amorim, J.E.B. Leite
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RESUMO Foram utilizados 30 cães neurologicamente saudáveis e realizadas radiografias da coluna cervical, sendo mensurada a menor distância atlantoaxial dorsal e outros parâmetros anatômicos vertebrais. Esses dados foram avaliados por meio do coeficiente de correlação de Pearson. Após detecção do melhor parâmetro de correlação, utilizou-se a fórmula de coeficiente de correlação dimensional (CCD). Na segunda etapa desta pesquisa, foram utilizadas imagens radiográficas de 33 cães com subluxação atlantoaxial (SAA) e aplicou-se a fórmula CCD. Todas as imagens atlantoaxiais normais e subluxadas foram distribuídas aleatoriamente e submetidas à análise subjetiva. Observou-se que o parâmetro anatômico de maior correlação foi o comprimento do processo espinhoso do áxis, obtendo-se valor de índice médio de 0,056 e desvio-padrão de 0,019. O valor de índice médio obtido em cães com SAA foi de 0,287, e o desviopadrão de 0,123. A análise subjetiva revelou acerto de 88,89% a 95,24%, enquanto a avaliação por meio da fórmula CCD demonstrou ser 100% eficiente no diagnóstico da SAA. Sugeriu-se a utilização da fórmula CCD para obtenção do índice de normalidade da distância atlantoaxial com valor de normalidade médio de 0,056 e limite máximo de 0,098, sendo esse índice eficaz no diagnóstico da subluxação entre o atlas e o áxis.

Normal index of dorsal atlantoaxial distance in dogs

ABSTRACT Thirty healthy dogs had their cervical spines radiographed, and the dorsal atlantoaxial distance and others vertebral anatomical parameters were measured. These data were assessed using the Pearson correlation coefficient. After detection of the best correlation parameter, we used the dimensional correlation coefficient of formula (CCD). In the second stage of the study, radiographs of the 33 dogs with atlantoaxial subluxation (SAA) were used. In each radiographic image, the CCD formula was applied. All normal and subluxation radiographic images were randomized, and submitted to subjective analysis. It was observed that the anatomical parameter with the highest correlation is the length of the spinous process of the axis, obtaining a mean value of 0.056 index and 0.019 standard deviation. Index mean value obtained in dogs with the disease of 0.287 and standard deviation of 0.123. The subjective analysis revealed 88.89% to 95.24% agreement, while the result obtained by the CCD formula was shown to be 100% effective in the diagnosis of SAA. We suggest the use of the CCD formula to obtain the index of normality of the atlantoaxial distance with a mean value of 0.056 and maximum of 0.098, and it is concluded that the index is highly effective in the diagnosis of subluxation between the atlas and the axis.