Azoospermia is the absence of sperm in the ejaculate, but it can have different causes. Depending on the reason for the azoospermia, the prognosis will be one or the other.
If it is due to a posttesticular factor (obstructive azoospermia), sperm production is not altered and sperm can be obtained directly from the testicle. However, if it is an alteration in sperm production (secretory azoospermia), it is very unlikely that sperm will be found in the testicle.
For more information on this male fertility problem, you can read the following article: Azoospermia