Quimionucleólise cervical associada à fenda ventral em cães: avaliação clínico-cirúrgica, radiográfica e histológica / [Chemonucleolysis of canine cervical intervertebral disks associated with ventral slots: Clinical-surgical, radiological and histological aspects]

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The present study has as objectives to evaluate the clinical-surgical, radiological and histological aspects of canine cervical intervertebral disks after chemonucleolysis with chymopapain associated to the ventral slot. For that, it was used 24 dogs randomly divided into six equal groups. The ventral slot was accomplished in the area of the intervertebral disk C2-C3 and chemonucleolysis in the other cervical disks. Each group of four animals was submitted to euthanasia with an anesthetic overdose 24 hours, eight, 30, 60, 90 and 120 days after the enzyme injection and sagittal sections of the treated disks, associated to adjacent cartilaginous endplates and bony structures were obtained for histological analysis. The dogs were also monitored clinically and radiographically for up to 120 days, according to the groups. In this study, all dogs tolerated the surgical procedure, without detectable postoperative pain, neurological deficit or alteration of the conscience state. In the radiographic evaluation, it was observed consistent disk space narrowing 24 hours after the procedure and total absence of space from the eighth to the 90th day after chemonucleolysis in the area of all treated disks. However, at 120 days of postoperative there was an increase in disk height, corresponding, on average, to 59.13% of the preinjection value. Also, on the 30th day of postoperative, it was noted absorption of the vertebral bodies adjacent to the treated disks that progressed to healing, with evidences of vertebral fusion 120 days after the treatment. In the histological evaluation, it was observed 24 hours after disk injection nuclear digestion, characterized by cavitations and decrease of safranin-O staining intensity, indicating loss of proteoglycans. At eight days, the nuclear content was still vacuolated but more fibrillar. At 30 days, it was noted lesions and hemorrhage in the cartilaginous endplates. An irregularly defined mass in the nuclear space was observed on days 60th and 90th, but it seemed fibrocartilaginous tissue on day 120th. It was also observed microfractures and bone necrosis on day 90th, which were healed by day 120th. Chemonucleolysis with chymopapain associated to the ventral slot in the cervical column of dogs determines lysis of intervertebral disks, cervical instability and lesions of cartilaginous and bone adjacent structures that tend to repair with fibrocartilaginous tissue along the time.

ASSUNTO(S)

quimionucleólise cervical intervertebral disks quimiopapaína diseases doenças fenda ventral cão treatment chymopapain ventral slot coluna cervical chemonucleolysis tecnica cirurgica animal tratamento dogs

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