Impact of fine- or large-needle aspiration on canine testes: clinical, in vivo ultrasonographic and seminological assessment

The safety and consequences of fine- (FNA) and large-needle aspiration (LNA) to the testicular parenchyma and its normal function have not been thoroughly established. This study was performed to accurately assess, by serial clinical, in vivo ultrasonographic and seminological examinations, the type and extent of the effect of FNA or LNA on canine testes. Eighteen sexually mature, 1-2 years old, healthy laboratory Beagles were used. One of their testes was aspirated using a 23-G butterfly needle (FN) and the other using a 19-G butterfly needle (LN). Two dogs at a time were orchiectomized 10, 60 min, 2, 14, 29, 63, 76, 90 or 180 days post-aspiration. Five and 2 days and 1 h before aspiration (in all dogs), immediately post-aspiration, and 1, 2, 4, 7, 9, 14, 19, 29, 35, 43, 49, 56, 63, 70, 76, 90, 111, 132 and 180 days post-aspiration (in the remaining intact dogs), evaluation of scrotal surface temperature over each testis, evaluation of scrotum-testis volume by electronic sliding callipers, ultrasonographic evaluation of testicular volume and texture and clinical and semen examination were performed. Following FNA and LNA, the clinical and ultrasonographic appearance of the testis were normal. Sperm production nearly always remained unchanged, with the exception of a slight decrease in spermatozoal motility 2-14 days post-aspiration. However, even then, with the exception of six samples, spermatozoal motility was above normal values. Within the parameters of this experiment, testicular FNA and LNA have no ill effect on sperm production or clinical and ultrasonographic appearance of the canine testis, and therefore, both FNA and LNA should be considered safe.