Testicular sperm extraction (TESE) is a surgical procedure in which a small portion of tissue is removed from the

testicle A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is Homology (biology), homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of Androgen, androgens, p ...

and any viable sperm cells from that tissue are extracted for use in further procedures, most commonly

intracytoplasmic sperm injection Intracytoplasmic sperm injection (ICSI ) is an in vitro fertilization (IVF) procedure in which a single sperm cell is injected directly into the cytoplasm of an egg. This technique is used in order to prepare the gametes for the obtention of embr ...

(ICSI) as part of

in vitro fertilisation In vitro fertilisation (IVF) is a process of fertilisation in which an ovum, egg is combined with spermatozoon, sperm in vitro ("in glass"). The process involves monitoring and stimulating the Ovulation cycle, ovulatory process, then removing ...

(IVF). TESE is often recommended to patients who cannot produce sperm by

ejaculation Ejaculation is the discharge of semen (the ''ejaculate''; normally containing sperm) from the penis through the urethra. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. ...

due to azoospermia.''''

Medical uses

TESE is recommended to patients who do not have sperm present in their ejaculate, azoospermia, or who cannot ejaculate at all. In general, azoospermia can be divided into obstructive and non-obstructive subcategories. TESE is primarily used for non-obstructive azoospermia, where patients do not have sperm present in the ejaculate but who may produce sperm in the testis. Azoospermia in these patients could be a result of Y chromosome microdeletions, cancer of the testicles or damage to the

pituitary gland The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans, the pituitary gland is located at the base of the human brain, brain, protruding off the bottom of the hypothalamus. The pituitary gland and the hypothalamus contr ...

hypothalamus The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...

, which regulate sperm production. Often in these cases, TESE is used as a second option, after prior efforts to treat the azoospermia through

hormone therapy Hormone therapy or hormonal therapy is the use of hormones in medical treatment. Treatment with hormone antagonists may also be referred to as hormonal therapy or antihormone therapy. The most general classes of hormone therapy are hormonal therap ...

have failed. However, if azoospermia is related to a disorder of sexual development, such as

Klinefelter syndrome Klinefelter syndrome (KS), also known as 47,XXY, is a chromosome anomaly where a male has an extra X chromosome. These complications commonly include infertility and small, poorly functioning testicles (if present). These symptoms are often n ...

, TESE is not used clinically; as of 2016, this was in the research phase. More rarely, TESE is used to extract sperm in cases of obstructive azoospermia. Obstructive azoospermia can be caused in a variety of ways: *

vasectomy Vasectomy is an elective surgical procedure that results in male sterilization, often as a means of permanent contraception. During the procedure, the male vasa deferentia are cut and tied or sealed so as to prevent sperm from entering into ...

* trauma * congenital absence of the

vas deferens The vas deferens (: vasa deferentia), ductus deferens (: ductūs deferentes), or sperm duct is part of the male reproductive system of many vertebrates. In mammals, spermatozoa are produced in the seminiferous tubules and flow into the epididyma ...

(CAVD) *

cystic fibrosis Cystic fibrosis (CF) is a genetic disorder inherited in an autosomal recessive manner that impairs the normal clearance of Sputum, mucus from the lungs, which facilitates the colonization and infection of the lungs by bacteria, notably ''Staphy ...

.'''' TESE can also be used as a fertility preservation option for patients undergoing gender reassignment surgery and who cannot ejaculate sperm.

Technique

Conventional TESE is usually performed under local, or sometimes spinal or general,

anaesthesia Anesthesia (American English) or anaesthesia (British English) is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prev ...

. An incision in the median raphe of the

scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...

is made and continued through the dartos fibres and the tunica vaginalis. The testicle and epidydymis are then visible. Incisions are then made through the outer covering of the testis to retrieve biopsies of seminiferous tubules, which are the structures that contain sperm. The incision is closed with sutures and each sample is assessed under a microscope to confirm the presence of sperm. Following extraction, sperm is often cryogenically preserved for future use, but can also be used fresh.

Micro-TESE

Micro-TESE, or microdissection testicular sperm extraction, includes the use of an operating microscope. This allows the surgeon to observe regions of seminiferous tubules of the testes that have more chance of containing spermatozoa. The procedure is more invasive than conventional TESE, requiring general anaesthetic, and usually used only in patients with non-obstructive azoospermia. Similarly to TESE, an incision is made in the scrotum and surface of the testicle to expose seminiferous tubules. However, this exposure is much more wide in micro-TESE. This allows exploration of the incision under the microscope to identify areas of tubules more likely to contain more sperm. If none can be identified, biopsies are instead taken at random from a wide range of locations. The incision is closed with sutures. Samples are re-examined post-surgery to locate and then purify sperm. When compared with FNA of the testis, conventional TESE is 2-fold more effective at identifying sperm in men with non-obstructive azoospermia. Compared with conventional TESE, micro-TESE has about 1.5-fold higher success in extracting sperm; as such, micro-TESE is preferable in cases of non-obstructive azoospermia< , where infertility is caused by a lack of sperm production rather than a blockage. In these cases, micro-TESE is more likely to yield sufficient sperm for use in ICSI.

TESE vs TESA

TESE is different to testicular sperm aspiration (TESA). TESA is done under local anaesthesia, does not involve an open biopsy and is suitable for patients with obstructive azoospermia.

Complications

Micro-TESE and TESE have risks of postoperative infection, bleeding and pain. TESE can result in testicular abnormalities and scarring of the tissue. The procedure can cause testicular fibrosis and inflammation, which can reduce testicular function and cause testicular atrophy. Both procedures can alter the steroid function of the testes causing a decline in serum testosterone levels, which can result in testosterone deficiency. This can cause side-effects including muscle weakness, decreased sexual function, anxiety, leading to sleep deficiency. The blood supply to the testis can also be altered during this procedure, potentially reducing supply. Long-term follow-ups are often recommended to prevent these complications. Micro-TESE has limited postoperative complications compared with TESE. The use of the surgical microscope allows for small specific incisions to retrieve seminiferous tubules and evade damaging blood vessels by avoiding regions with no vasculature. If TESE needs to be repeated due to insufficient sperm recovery, patients are usually advised to wait 6–12 months in order to allow adequate healing of the testis before further surgery.

References