A testicular biopsy (Testicular Sperm Extraction or TESE) allows for sperm to be directly collected from the testicle, where sperm production takes place. However, after such a long period of time with a voluntary obstruction, it is likely that the organism has decreased the number of sperm it produces. The good news is that, since ICSI technique could work with just a single sperm, a woman could get pregnant with only few sperm retrieved after TESE.
In any case, one should bear in mind that it is possible that zero sperm are found in the sample after a testicular biopsy.