Ascending coccygeal venography in evaluation of paraplega in dogs

Abstract

The study was undertaken with an objective of evaluating the comparative efficacy of ascending coccygeal venography and epidurography in locating the site and type oflesion in dogs suffering from paraplegia. The study was conducted in 12 clinical cases presented at the Surgery unit of Veterinary College Hospital, Mannuthy and were designated into two groups (Group A and B) of 6 animals each. Survey radiographs were taken in all the animals prior to the contrast radiographic procedures. Iohexol (300 mgIfrnl) was used as the contrast medium at a dose rate of 80 mgIlkg body weight for epidurography and 100 mgIlkg body weight for ascending coccygeal venography. In Group A, epidurography was conducted by introducing the contrast medium through the lumbosacral junction into the epidural space. The contrast medium was given as slow infusion and the zero minute radiograph was taken, as the last milliliter of the contrast medium remained to be injected. Subsequent radiographs were taken at the 3rd and the 5th minute. In Group B, ascending coccygeal venography was conducted by introducing the contrast medium intravenously as slow infusion into the superficial lateral coccygeal vein of anyone side near the base of the tail, after sufficient abdominal compression. Lateral/ventrodorsal radiographs were taken, as the last milliliter of the contrast remained to be injected. Subsequent radiographs were taken at the 3rd and the Sth minute. All the animals were subjected to a thorough clinical and neurological examination prior to radiography. Physiological and haematological parameters were evaluatedjust before and 24 hours after radiography. All the animals were observed for one week for the presence of any side effects/complications. The physiological and haematological parameters were within the normal range in all the animals both before and 24 hours after radiography. Iohexol was found safe for neuroradiological studies as none of the animals exhibited any side effects/complications during the period of observation for one week. In Group A, epidurography produced good quality radiographs and was consistent in all the six cases. Abnormalities/lesions could be located in four cases. The remaining two cases showed normal epidurographic pattern and could not be correlated with the neurological examination. In Group B, successful venograms were obtained in three cases in which lesions were located and correlated with the neurological examination. In the remaining three cases, the venous sinuses could not be opacified and hence failed in identification oflesion. The changes identifiable as lesions in Group A were attenuation of the contrast col W11l1 , considerable narrowing and elevation of the column, and failure of the opacification ofa specific region of the column. The changes identifiable with a lesion in venography were abrupt attenuation of the venous sinuses, considerable elevation of the venous sinuses and progressive thinning and attenuation of the veins. Thus epidurography showed consistency III all the SIX cases and diagnosis could be made in four out of six cases whereas diagnostic venograms were obtained only in three out of six cases. Thus ascending coccygeal venography was found inconsistent and required further studies before recommending this as a routine practice. Though epidurography possessed a distinct advan tage over ascending coccygeal venography in consistency and technical and diagnostic feasibility, epidurography couldnot be advocated as a sole diagnostic procedure and should be used as an adjunct with other .diagnostic aids after proper clinical and neurological examination.