Micro-epididymal sperm aspiration (MESA) is an outpatient microsurgical procedure for collecting sperm in men who have an absence of sperm in their ejaculate, generally known as azoospermia. There may be several reasons for this, such as poor motility or blockage of the male reproductive duct. Azoospermia can be seen in men who have been diagnosed with absence of the vas deferens, which occurs in cystic fibrosis. However, cases where such a blockage occurs intentionally, such as a prior vasectomy, are far more common.
Similar to other assisted reproductive therapies, micro-epididymal sperm aspiration may be suitable for couples who have been unable to conceive despite having tried for at least a year, and have identified the cause as a male-related disorder. Additionally, semen and sperm morphology analyses may be done prior to MESA to determine whether it is appropriate. Generally, men whose sperm have been shown to have poor motility are also candidates for this procedure.
Micro-epididymal sperm aspiration is performed by a consultant urologist. The patient is placed under general anesthesia. Once he is sedated, the urologist makes a small incision in the scrotum to expose the epididymis, the duct that stores the sperm, located behind each testis.
As soon as the sperm are harvested, they are often prepared for intracytoplasmic semen injection to be performed on the female partner on the same day.
General and reproductive health of both the male and female partner contributes to the success of this procedure towards resulting in pregnancy. Since absence of the vas deferens can be a feature of cystic fibrosis, which in turn is due to a chromosomal abnormality, both partners should undergo genetic counseling to help them consider the best option for treating infertility.