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Men with azoospermia can father a child through intra-cytoplasmic sperm injection if sperm can be retrieved from their epididymis or testis. Several percutaneous and open surgical procedures have been described to retrieve sperm. The various techniques and their merits are discussed in this review. In men with obstructive azoospermia, epididymal sperm can usually be retrieved by percutaneous epididymal sperm aspiration (PESA). If PESA fails then testicular sperm are obtained by needle aspiration biopsy (NAB). In men with non-obstructive azoospermia, there will be no sperm in the epididymis and testicular sperm retrieval is required. Percutaneous retrieval by NAB can be tried first. If that fails then testicular sperm extraction (TESE) from open microsurgical biopsies is performed using the single seminiferous tubule (SST) or the microdissection TESE techniques. The simplest, least invasive procedure should be tried first.

INTRODUCTION

In the past, the only options for treating azoospermia were reconstructive surgery (if there was obstruction) or donor insemination. Now, the advent of intra-cytoplasmic sperm injection (ICSI) has enabled many azoospermic men to become biological fathers using sperm obtained from their epididymis or testis. Pregnancy rates with ICSI are the same whether ejaculated, epididymal or testicular sperm are used.[1]

Epididymal sperm retrieval for in vitro fertilization (IVF) was first described for a case of secondary obstructive azoospermia.[2] The authors used a micro-pipette to puncture the exposed epididymal ductule and aspirate sperm. Subsequently, Silber popularized an open technique for men with vas aplasia, in which the epididymal ductule was dissected microsurgically, opened, aspirated, and then sutured close (MESA).[3] We modified this procedure by directly aspirating sperm from the exposed epididymis with a simple 26-G needle without any microsurgical dissection or suturing (OFNA).[4] Shrivastava et al., described an alternative, simpler procedure in which the aspiration was performed percutaneously (PESA).[5]

Testicular sperm were first used for IVF and ICSI for men with obstructive azoospermia.[6–8] Subsequently, Devroey et al,.[9] showed that even in men with testicular failure sperm could be retrieved from the testis in many cases and ICSI successfully performed. Accordingly, men with testicular failure were subjected to multiple open biopsies in an attempt to locate focal areas of spermatogenesis. However, several studies showed that multiple conventional biopsies damaged the testes.[10,11] Hence, instead, Schlegal and Li[12] proposed selective micro-biopsies, using magnification to identify favorable seminiferous tubules (microdissection-testicular sperm extraction (TESE)), as a technique for taking extensive biopsies while minimizing damage. Subsequently, we described an alternative method of acquiring multiple micro-biopsies, while causing less trauma, by taking single seminiferous tubule biopsies through puncture holes in the tunica (SST technique).[4] Recently, the use of ultrasound has been described both for avoiding blood vessels during percutaneous procedures and for indentifying areas of increased vascularity that may be more likely to harbor sperm.[13,14]

This review will describe and compare the various methods of epididymal and testicular sperm retrieval.