Cornell University

Cornell University
Weill Medical College

Cornell Institute for Reproductive Medicine

Center for Male Reproductive Medicine and Microsurgery

"State-of-the-Art Compassionate Care for the Infertile Couple"

Surgical Sperm Retrieval: Which Method to Use?

  1. Introduction
  2. Evaluation of azoospermic men
  3. Evaluation for non-obstructive azoospermia (testicular failure)
  4. Distinction between obstructive and non-obstructive azoospermia
  5. Sperm quality in obstructive and non-obstructive azoospermia
    1. Obstructive Azoospermia
    2. Non-obstructive Azoospermia
  6. Genetic Evaluation of Men with Azoospermia
  7. Sperm Retrieval Techniques
    1. Testicular Fine Needle Aspiration (TFNA)
    2. Percutaneous Epididymal Sperm Aspiration (PESA)
    3. Percutaneous Biopsy of the Testis (PercBiopsy)
    4. Microsurgical Epididymal Sperm Aspiration
  8. Surgical Sperm Retrieval for Non-obstructive Azoospermia (NOA)
    1. Multiple Standard/testicular Biopsy and Percutaneous Biopsy
    2. Microdissection Testicular Sperm Extraction (TESA)
    3. RealVideo Clips: Microdissection TESE: Sperm Retrieval in Non-Obstructive Azoospermia
        Part 1: Introduction
        Part 2: General Review TESE
        Part 3: Review Other Techniques for Sperm Retrieval
        Part 4: Surgical Technique: Microdissection TESE
        Part 5: Results and Discussion
  9. Cryopreservation of Epididymal and Testicular Sperm
  10. Conclusions
  11. Future Directions
  12. Reference and Suggested Reading


In the past five years, very few fields in modern medicine have changed as dramatically as reproductive medicine, especially for the new treatment of male infertility by use of (1) intracytoplasmic sperm injection (ICSI) techniques1 (Figure 1) and; (2) advanced surgical epididymal and testicular sperm retrieval techniques.2,3,4,5,6 Those two major technical advances have completely changed the treatment for previously untreatable testicular failure or unreconstructable obstructive azoospermia. ICSI is highly efficient at producing fertilization as long as the spermatozoa are conceivable and can be retrieved from male reproductive tract.

Evaluation of azoospermic men

Prior to sperm retrieval, initial evaluation of female partner should be carried out to confirm that she has adequate ovarian reserve to undergo assisted reproduction for IVF-ISCI procedure.

For men with low semen volume (< 1ml), a postejaculate urinalysis should be performed to rule out retrograde ejaculation. A complete history is needed to assess for risk factors that may have led to azoospermia, such as cryptorchidism bilateral inguinal hernia procedures, or family history of cystic fibrosis. A man with a history of cryptorchidism and testicular capacity of 8 ml most likely has non-obstructive azoospermia (NOA), whereas the patient with bilaterally absent vasa, testicular volume of 16 ml or greater, and an enlarged caput epididymis almost certainly has obstructive azoospermia. The physical examination should also be thorough, with special attention to the volume of the testes (normal finding is greater than 15 ml), presence of epididymal dilation of fullness that suggestive of obstruction, and the existence of the vasa deferens. The testis should be carefully examined for tumors, a not uncommon cause of azoospermia and the most common cancer in men 15-45 years old. Ancillary evaluation, such as transrectal ultrasound, may examination help to determine if ejaculatory duct obstruction is presented. Scrotal ultrasound can be helpful for men with scrotal masses or a history of cryptorchidism to detect small testis tumor. (Table 1)

Evaluation of Azoospermic Men
Serial semen analyses
    ( with centrifugation and pellet examination)
Complete history
Physical examination
Serum hormones
    Follicle-stimulating hormone (FSH)
    Testosterone( T)
Ancillary testing:
    Postejaculate urinalysis
    Transrectal ultrasound
    Scrotal ultrasound

Evaluation for non-obstructive azoospermia (testicular failure)

Non-obstructive azoospermia is a condition in which no sperm are present in the ejaculate because of severely abnormal sperm production. Most of these men have small-volume testes, elevated follicle-stimulating hormone, and empty epididymides. In this condition, a diagnostic therapeutic testis biopsy will reveal abnormal sperm production.

Evaluation for Non-obstructive Azoospermia

1. History:
    Cryptorchidism; Chemotherapy; Genetic abnormalities
2. Physical Examination:
    Small, soft testes ( <15 ml); Empty or flat epididymis
3. Semen Analysis:
    Normal volume; Fructose present; No spermatozoa
4. Hormone Levels:
    Elevated levels of follicle-stimulating hormone
    Borderline to low testosterone
    Borderline to elevated estradiol

The general histologic patterns are found in men with non-obstructive azoospermia (NOA) are Sertoli cell-only, maturation arrest and hypospermatogenesis. 7,8

(1): Sertoli cell-only syndrome: In this condition, only the supporting cells (Sertoli cell) are present, with no germ cells in the seminiferous tubules.

(2). Maturation arrest. Maturation arrest is a condition in which Sertoli cells and immature germ cells are present in seminiferous tubules

(3). Hypospermatogenesis. hypospermatogenesis signifies a defect in sperm production in which decreased numbers of germ cells are present in seminiferous tubules but rare or no mature spermatids are present within the testis.

Distinction between obstructive and non-obstructive azoospermia

Prior to initiating treatment for a couple, in whom the man has azoospermia, it is important to distinguish whether the lack of sperm in the ejaculate is from an obstructive or non-obstructive process. In addition, careful evaluation of the post-ejaculate urinalysis is necessary to rule out retrograde ejaculation, common in diabetics. Men with retrograde ejaculation do not require invasive procedures for sperm retrieval; sperm may be isolated from urine or catheterized from the bladder and used for intrauterine insemination or IVF. Paraplegics may be treated with vibratory stimulation or electro-ejaculation and do not require surgical sperm retrieval. History and physical examination can suggest the cause of azoospermia for an experienced examiner. For example, the presence of normal volume testes with bilaterally indurated epididymides and/or absent vas deferens will point to an obstructive etiology for azoospermia. A history of cryptorchidism in the presence of small or soft testes suggests non-obstructive azoospermia (NOA), especially if associated with an elevated serum (FSH) level.

The distinction between obstructive and non-obstructive azoospermia is important. Men with obstructive azoospermia may have other cost-effective options for treatment, such as microsurgical reconstruction of the reproductive tract. Also, a real risk of failure to retrieve spermatozoa exists in men with non-obstructive azoospermia (NOA), and couples must be apprised of this risk before attempting assisted reproduction with sperm retrieval and ICSI. Men with NOA azoospermia often have a genetic abnormality that has caused the lack of sperm, whereas most men with congenital absence of the vas deferens have abnormalities of the cystic fibrosis (CFTR) gene.

Sperm quality in obstructive and non-obstructive azoospermia

In the normal male reproductive tract, sperm exiting the testis have minimal motility and limited egg fertilizing capacity. Sperm acquire the potential for improved motility and fertilizing ability during epididymal transit. So, in the unobstructed epididymis, sperm of optimal quality (as evaluated by percent motile cells) are found in the most distal epididymis.

1. Obstructive Azoospermia: The obstructed epididymis or congenital absence of the vas deferens shows the opposite pattern of sperm quality: optimal sperm quality in the proximal epididymis and very poor quality in the most distal segments. This finding of "inverted motility" is expected in the obstructed male reproductive tract since sperm production that continues in the testis and reabsorption of those sperm is an active process in the most distal regions of the system. The most distal obstructed epididymis tends to contain dilated yellow tubules that are packed with macrophages reabsorbing old, degenerated sperm.9 Therefore, sperm retrieval should be performed from the proximal obstructed epididymis and testis, and higher quantities of motile spermatozoa can be obtained. In fact, motile spermatozoa are found at concentrations up to 1 million sperm per microliter in the fluid of obstructed epididymis.

2. Non-obstructive Azoospermia: A common observation for testicular sperm samples is that retrieved spermatozoa are immobile or have a sluggish twitching motion. In this situation, some sperm production is focally present within the testis, despite the fact that inadequate numbers of sperm are released from the testis to make it into the ejaculate. After several hours of incubation in vitro, testicular sperm typically show some motility. The lack of initial motility does not necessarily reflect a lack of viability for testicular sperm, since these sperm have never acquired motility. Non-motile ejaculated sperm have acquired and lost motility, as sperm viability is lost, rendering the sperm useless for ICSI.

Typical criteria for poor sperm production, including an elevated serum FSH level or decreased testicular volume, does not predict which patients have sperm found with testicular sperm extraction (TESE). Even the histologic patterns on diagnostic testicular biopsy (Sertoli cell-only, maturation arrest, hypospermatogenesis) cannot perfectly predict the chance of finding sperm with TESE. However, many centers require diagnostic biopsies prior to TESE procedures to rule out carcinoma-in-situ (intratubular germ cell neoplasia) that is present in up to 3% of men with NOA who are candidates for treatment with TESE-ICSI.8

Genetic Evaluation of Men with Azoospermia

The diagnosis of azoospermia is often associated with a genetic etiology. For men with congenital absence of the vas deferens, 60% will have a detectable cystic fibrosis gene mutation.10 The female partner should also be tested to see if she is a carrier. If both partners are carriers, the risk of having a child affected by crystic fibrosis is 50%. Up to 17% or more men with NOA will have detectable genetic abnormalities that will only become apparent with the rudimentary tests of Y-chromosome partial deletion analysis and karyotype testing.

Genetic Analysis of Men with Azoospermia

Obstructive Azoospermia
    Cystic fibrosis gene mutation analysis of wife
    Cystic fibrosis testing for husband
Non-obstructive Azoospermia
    Karyotype analysis
    Y-chromosome microdeletion analysis
    ?? Other gene deletion/mutations

Normal male chromosome analysis depicts 46 chromosome with an XY complement of sex chromosomes. Common abnormalities seen in men with NOA includes Klinefelter's syndrome (47, XXY), autosomal translocations, and other sex chromosome anomalies (46, XX).

Schematic depiction of the Y chromosome: From the above figure, the solid bars indicate the presence of genetic material, determined by polymerase chain reaction (PCR)-based analysis of Y-chromosome sequence-tagged sites. The dashed regions indicate areas where genetic material is missing in various men with non-obstructive azoospermia. The detection of Y-chromosome deletions involving the AZFb region (as in patients SMG32, SMG78, SMG 126), is of prognostic values, because it indicates a high risk of failure to find sperm during attempts at sperm retrieval.11

In addition, other chromosomal abnormalities, detectable on karyotype analysis are frequently found on evaluation of men with NOA, and may be transmitted to offspring by ICSI procedures. When genetic abnormalities are found, the couple should be referred for genetic counseling prior to attempts at assisted conception. Since some attempts at sperm retrieval are not successful for men with NOA, the potential for use of donor spermatozoa should be raised with the couple. In many cases, the couple is ambivalent regarding this option and psychological counseling may be helpful to review the implications for the couple of having a child who is not genetically related to the father.

Sperm Retrieval Techniques

Sperm retrieval is indicated in men at the time of difficult surgical reconstruction, as well as in individuals with unreconstructable reproductive tract obstruction, or for men with obstruction who refuse surgical reconstruction.

The goals of surgical sperm retrieval are: (1) to obtain the best quality sperm possible; (2) to retrieve an adequate number of sperm for both immediate use and for cryopreservation, and (3) to minimize damage to the reproductive tract so as not to jeopardize future attempts at sperm retrieval or surgical reconstruction.

1. Surgical Sperm Retrieval for Obstructive Azoospermia

(1) Testicular Fine Needle Aspiration (TFNA): The technique of testicular fine-needle aspiration (TFNA) of the testis was initially described as a diagnostic procedure in azoospermic men. Subsequently, testicular fine needle aspiration or biopsy for the recovery of spermatozoa has been described12, 14. Percutaneous puncture and aspiration of the testis can be performed using a 21-23-gauge needle connected to a 20cc syringe in a Menghini syringe holder. Percutaneous testicular needle biopsy can be performed with an automatic biopsy gun. The limited published experience to date with TFNA makes critical evaluation of this technique difficult, although it is evident from our experience that 1) sperm retrieval is routinely possible with TFNA for men with obstructive azoospermia, 2) occasional hematoceles and hematomas are possible with this technique. The advantages of percutaneous aspiration techniques are that they can be performed with local anesthesia, without open scrotal exploration and its attendant postoperative discomfort, and without microsurgical expertise.

(2) Percutaneous Epididymal Sperm Aspiration (PESA): PESA has been advocated because it can be performed without surgical scrotal exploration, it is repeated easily at low cost, and it does not require an operating microscope or expertise in microsurgery. The procedure can be performed under local or general anesthesia. The testis is stabilized and the epididymis is held between the surgeon's thumb and forefinger. A 21-gauge butterfly needle attached to a 20-ml syringe is inserted into the caput epididymis and withdrawn gently until fluid can be seen entering the butterfly needle tubing. The procedure is repeated until adequate numbers of sperm are retrieved. PESA yields very small amount of epididymal fluid and contamination with blood cells is frequent. For the 10-20% of attempts where sperm are not retrieved with PESA, open sperm retrieval or percutaneous testicular aspiration is possible.

(3) Percutaneous biopsy of the testis (PercBiopsy): Percutaneous biopsy retrieval is an effective technique that provides the higher yield of spermatozoa for sperm retrieval in obstructive azoospermia, in our experience at Cornell.12,14 A 14-gauge automatic biopsy gun with a 1-cm excursion is used (Microvasive ASAP Channel cut Biopsy system, catalog#1234, Boston, MA, USA) under local anesthesia to remove a small segment of testicular parenchyma.

(4) Microsurgical Epididymal Sperm Aspiration (MESA): Microsurgical epididymal sperm aspiration is performed as open operation under the operating microscope. Individual tubules of the epididymis are isolated and micropuncture aspiration is taken. This approach has the advantages of reliable retrieval of large numbers of epididymal spermatozoa that can be readily frozen and thawed for subsequent attempts at fertility. Since MESA involves direct retrieval of spermatozoa from epididymal tubule, it minimizes contamination of the epididymal fluid by blood cells, which may affect spermatozoa fertilizing capacity during the IVF.

MESA is performed with a micropuncture siliconized glass pipette connected to sterile medical grade silicone tubing that is attached to an aspiration device consisting of a 1-ml plastic tuberculin syringe and a 10-ml glass syringe. The tip size of micropuncture pipette is about 250 to 350 Ám sharpened on a fine grinding wheel to facilitate puncture of the epididymal tubule.9,12,14 A unique micropuncture pipet holding apparatus, MESA- Holder (Patent pending, Cornell Research Foundation, 1997) has been developed at Cornell. Its unique 180o angle adjustable pipet holding system simplifies the procedure of micropuncture epididymal sperm retrieval. With gentle aspiration, epididymal fluid passes into the micropipet, through the silicone tubing, and into a plastic syringe. Sequentially more proximal punctures are performed until optimal sperm quality has been obtained. Puncture sites are then closed with interrupted 9-0 Nylon suture, or cauterized and the epididymal tunic closed with 6-0 polypropylene suture.

Epididymal sperm can also be retrieved by an opening individual epididymal tubule with a micro-knife and collecting the sperm though a simple micropipette/capillary action technique during some epididymal reconstructive microsurgeries.4 It provides a direct visual confirmation and quantification of epididymal fluid recovery. It is a simple, inexpensive and safe sperm recovery technique for the microsurgery vasoepididymostomy. Its device is consisted of a 10-ml syringe connecting to a short segment of medical grade silicone tubing (4 to 6 cm long) and a blunt-tip micropippet.

For each sperm retrieval, epididymal fluid was immediately examined under a phase contract microscope at 200 x power by an embryologist to evaluate the concentration and motility of the spermatozoa as well as the degree of blood cells contamination. Typically only few microliters of epididymal fluid need to be retrieved, because sperm in the epididymal fluid is highly concentrated (roughly 1 x 106 sperm/Ál, so that each MESA approach should provide for more than adequate numbers of sperm for immediate use, as well as for cryopreservation. Retrieval sperm from epididymis of men with obstructive azoospermia is possible in over 99% of patients by experienced microsurgeons, even if multiple prior procedures have been performed and extensive scaring is presented in the scrotum in our experience at Cornell. Initially, sperm retrieval was performed in conjunction with IVF of limited forms of micromanipulation, such as partial zona dissection. With the introduction of ICSI, this form of manipulation has replaced all other types of assisted reproduction.

MESA-ICSI: Cornell Experience (1998)
Fertilization rate/oocyte
Clinical pregnancy
80% (665/833)
75% (57/76)
64% (49/76)

In the most recent 76 attempts at sperm retrieval using MESA and ICSI for men with obstructive azoospermia, clinical pregnancies were detected by a fetal heartbeat in 75% (57/76) of attempts, with ongoing pregnancy or deliveries for 64% (49/76) of attempts. Optimal fertilization and pregnancy rates are obtained with a technique of aggressive immobilization of spermatozoa prior to ICSI. Aggressive immobilization may act by enhancing sperm membrane permeability to improve the ability of immature spermatozoa to fertilize oocytes.13, 14

Schlegel and colleagues compared the efficacy and reliability of sperm retrieval by testicular fine needle aspiration (TFNA), percutaneous testicular needle biopsy (PercBiosy) for patients with obstructive azoospermia at Cornell. Results indicated that MESA was the optimal choice to retrieval the greatest number of spermatozoa (MESA with 15 x106 sperm/per microliter, vs. TFNA with 0.014 x106; PercBiopsy with 0.116 x106 ) and highest motility ( MESA-15%; PercBiopsy-2% and TFNA with 0%) for assisted reproductive and subsequent cryopreservation.12

2. Surgical Sperm Retrieval for Non-obstructive Azoospermia

Testicular sperm may be found within testicular tissue of many men with non-obstructive azoospermia. The optimal technique of sperm extraction would be minimally invasive and avoid destruction of testicular function without compromising the chance of retrieval adequate numbers of spermatozoa to perform ISCI.

(1): Multiple Standard/ Testicular Biopsy and Percutaneous Biopsy: Under either a local or general anesthesia, an open window through a scrotal incision of testis biopsy is used. The tunica albuginea is opened for obtaining a large volumes or multiple samples of testicular tissue. This technique may create a potential devascularization problems, because the limited blood supply of testicle course underneath the tunica albuginea of the testis before it penetrates into the testicular parenchyma. Multiple incisional biopsies or percutaneous biopsy should be avoided or cautiously performed, because these interventions could involve injury to enough of testicular blood supply to risk testicular devascularization.15 ( Above figure was from Dr. JP. Jarow, with permission)

In general, percutaneous approaches have yielded much lower rates of sperm retrieval in non-obstructive azoospermia than that achieved by more invasive techniques.16 The multiple biopsy technique initially described by Devroey et al. provides good retrieval rates despite the need for multiple incisions in the tunica albuginea.17 We reported that the retrieval of spermatozoa using removal of large volumes of testicular tissue through a single incision resulted in a similar retrieval with less risk to the testicular blood supply but might loss of a greater volumes of testicular tissue.5 We have combined these two techniques with the assistance of an operating microscope and have successfully developed a technique as Microdissection of testicular sperm extraction (TESE).

Approaches to Testicular Sperm Retrieval for Non-obstructive Azoospermia ( NOA)
  • Multiple standard ( large) Biopsy
  • Percutaneous aspiration/Biopsy
  • Microdissection of Testis Tubules

(2). Microdissection Testicular Sperm Extraction (TESA):18, 19 Testicular sperm extraction (TESE) is an effective method for sperm retrieval from men with non-obstructive azoospermia for ICSI. However, the conventional TESE technique requires multiple blind testis biopsies, with excision of large volumes (>700 mg) of testicular tissue and risks permanent damage to the testis. Using optical magnification, a relatively avascular region of the testis is located for an incision.

After the testicular capsule has been opened, individual tubules are examined under approximately 20 to 25x magnification. The testicular blood supply is easily identifiable. The testicle has also been inspected for the presence of a spermatogenically active region of normal seminiferous tubules, which containing many developing germ cells. Those tubules are usually larger and more opaque than tubules without sperm production( indicated in the figure on the right side by the tip of the micro-scissors), and therefore easily distinguishable from Sertoli cell-only, or sclerotic tubules that are much smaller in diameter.

The efficacy of sperm retrieval, by sequential excision of microdissected testicular tubules (<10mg or 2mm in length of seminiferous tubule), was shown by comparing results achieved using conventional techniques of TESE, or biopsies from adjacent areas of testicular tissue. Schlegel has shown that microdissection improved sperm retrieval rates from 45% (10/22) to 63% (17/27) in a sequential series of TESE attempts. Microdissected samples yielded an average of 160,000 spermatozoa per sample in only 9.4 mg. of tissue, whereas only 64,000 spermatozoa were found in conventional biopsy samples that averaged 720 mg. in volume (P<0.05 for all comparisons.).

Using a microdissection TESE technique for men with non-obstructive azoospermia, a minimum amount of testicular tissue is excised and a sufficient number of spermatozoa can still be retrieved. Optical magnification allows for the identification of avascular regions of the testis to minimize risks of testicular injury. Microdissection is a safer and more efficient technique for sperm extraction in men with non-obstructive azoospermia. For men with at least one area of hypospermatogenesis, 81% of men had sperm retrieval, whereas when men the most advanced spermatogenesis form was maturation arrest, 42% of men has sperm retrieved. When most advanced spermtogenic pattern was that Sertoli Cell-only, only 24% of men have sperm retrieved.
It should also be noted that the histologic evaluation differs from the standard approach of describing the predominant histologic pattern, since sperm retrieval is dependent on the most advanced patter, not the predominant pattern within the testis.18

Biopsy PatternSperm Retrieved
Sertoli Cell-only
Marturation Arrest
24% (5/21)
42% (8/19)
81% (31/39)

*NYPH-WMCU, 1998

Our overall results at Cornell in 81 attempts sperm retrieval cycles with testicular sperm extraction for men with non-obstructive azoospermia is shown in the following table. Sperm were found for 58% ( 47/81) of the men. The fertilization rate was 60% per injected oocyte and clinical pregnancy was achieved in 55% of the cycles in which sperm were retrieved. Ongoing pregnancies or deliveries have occurred for 40% of cycles with sperm. Overall, for all couples attempting sperm retrieval including cases whereas no sperm were available for injection, the overall ongoing delivered rate was 23%.

NOA: Results of 81 Attempted Sperm Retrieval Cycles with TESE
Retrieval Attempts ( 81)

Sperm retrieved
Fertilization rate/oocyte
Clinical pregnancy
Overall ongoing/delivered

58% (47/81)
60% (231/386)
55% ( 26/47)
40% (19/47)
23% (19/81)


Video Clips: Microdissection TESE: Sperm Retrieval in Non-Obstructive Azoospermia

Cryopreservation of Epididymal and Testicular Sperm

Successful sperm cryopreservation allows the opportunity for multiple ICSI cycles without the need for additional sperm retrieval procedures. Since ICSI enables even severely impaired sperm to effect oocyte fertilization, as long as sperm are viable, cryopreserved sperm can achieve rates of fertilization and pregnancy similar to fresh sperm. Cryopreservation also allows the potential for temporal separation of sperm retrieval procedures from assisted reproductive techniques. For obstructive azoospermia pregnancy rates for frozen and fresh epididymal sperm are virtually identical for NOA, fresh sperm is preferable. Freezing of isolated spermatozoa from testicular tissue is difficult because of the low number of spermatozoa present in testicular tissue and the limited sperm motility of testicular sperm, which makes documentation of sperm viability difficult. Nevertheless, anecdotal reports have indicated that it is possible to cryopreserve testicular biopsy tissue samples and subsequently extract spermatozoa after thawing with at least isolated pregnancies achieved.


Sperm retrieval from men with non-obstructive and obstructive azoospermia is now possible with excellent pregnancy rates for obstructive azoospermia and acceptable pregnancy rates for NOA when ICSI is applied. The ability to use cryopreserved epididymal and often testicular spermatozoa will continue to limit the number of sperm retrieval procedures necessary to achieve fertility for a couple. These advancements, both in sperm retrieval and assisted reproduction, provide the potential of fertility treatment where the only management options were donor insemination or adoption only several years ago. Specific genetic abnormalities are associated with azoospermia in men and careful evaluation of the cause of azoospermia is indicated for all men. Multiple TESE procedures may cause both transient and occasional permanent alterations in testicular function including testicular atrophy and decrease testosterone levels. Therefore, sperm retrieval should preferably be performed by physicians experienced in testicular anatomy and physiology and using an operating microscope.

The location of optimal sperm quality in obstructed is in the proximal portions of the epididymis, vas efferentia, and rete testis, whereas the distal obstructed reproductive tract is the site of sperm degeneration. Spermatozoa retrieved from the testis have been successful in achieving fertilizations and pregnancies for couples in whom epididymal aspiration failed, however reported fertilization and pregnancy rates have been lower than those achieved with epididymal spermatozoa. Of the sperm retrieval and assisted reproductive techniques, the most successful combination reported to date is microsurgical epididymal aspiration with intracytoplasmic sperm injection with fertilization rates and pregnancy rates as high as 45 and 52 percent, respectively.

The greatest published experience to-date with retrieved spermatozoa and ICSI involves patients who had sperm retrieved by MESA. The concentration and motility of epididymal sperm retrieved by MESA is reliably better than that retrieved from the same patients with TFNA or percutaneous testicular biopsy. In our experience with over 150 MESA procedures at Cornell, sperm retrieval from the epididymis with MESA is possible in over 99% of cases. In conclusion, MESA is the optimal choice for retrieval of sperm and subsequent cryopreservation for men with obstructive azoospermia. However, percutaneous testicular retrieval does not require microsurgical expertise and is less invasive.

Future Directions

Further data will allow definition of how to more effectively extract sperm from men with non-obstructive azoospermia, and in vitro manipulation of retrieved sperm from men with obstructed systems may allow optimized results. The role of incompletely developed spermatozoa (i.e., spermatids) for treatment of men with NOA will also be clarified over time. Anecdotal pregnancies and deliveries for men with NOA have been reported using spermatids injected into the female partner's oocytes after extraction of those spermatids from the ejaculate or testis. However, spermatids usually cannot be extracted from the testis if TESE does not yield fully developed spermatozoa. However, these areas of treatment are new, and spermatogonial transplants as well as the use of spermatids for fertilization have been reported in animal models. Since many men with NOA may have significant genetic abnormalities, caution must be exercised before widespread application of these fertility treatments can be accepted as standard therapy.

Whether percutaneous and open sperm retrieval will have equal pregnancy results has yet to be determined. MESA procedures have a more reliable record of sperm retrieval and acquisition of sperm for cryopreservation. Slightly lower, but adequate sperm retrieval and good pregnancy results are achieved with percutaneous techniques with less morbidity. Most importantly, centers should not limit couples' options for treatment based on their own technical limitations, but always provide the option of ICSI with sperm retrieval and the opportunity for microsurgical retrieval to limit the number of sperm retrieval procedures a man must endure.

Suggested Reading

1. Palermo G, Joris H, Devroey P, et al.: Pregnancies after intracytoplasmic injection of single spermatozoon into an oocyte. Lancet 340:17, 1992.

2. Girardi SK, Schlegel PN. Microsurgical epididymal sperm aspiration: Review of techniques, preoperative considerations, and results. J Androl 1996;1:5-9.

3. Sheynkin YR, Schlegel PN. Sperm retrieval for assisted reproductive technologies. Contemporary OB/GYN 1997;15: 113-129

4. Matthews GJ, Goldstein M. A simplified method of epididymal sperm aspiration. Urology 1996; 47:123-125

5. Schlegel PN, Palermo GD, Goldstein M, et al. Testicular sperm extraction with ICSI for non-obstructive azoospermia. Urology, 1997; 49:435-440

6. Silber SJ, Nagy ZP, Liu J, et al: Conventional in-vitro fertilization versus intracytoplamic sperm injection for patients requiring microsurgical sperm aspiration. Hum Reprod 1994,9:1705-1709

7. Jow WW, Steckel J, Schlegel PN, Magid MS, Goldstein M. Motile sperm in human testis biopsy specimens. J Androl 1993; 14:194-198.

8. Ostad M, Liotta D, Ye Z, et al: Testicular sperm extraction with optimized tissue dispersion. Urology 52:692-697, 1998

9. Schlegel PN, Berkeley AS, Goldstein M, et al .: Epididymal micropuncture with in vitro fertilization and oocyte micromanipulation for the treatment of unreconstructable obstructive azoospermia. Fertil Steril 1994, 61:895-901

10. Mak Z, Jarvi K.: Genetics of male infertility. J. Urol 1996, 156:1245-1257

11. Girardi SK, Mielnik, Schlegel PN: Submicroscopic deletions of the Y chromosome in infertility men. Hum Reprod 1997, 12:1635-1641

12. Sheynkin YR, Ye Z, Menendez S, Liotta D, Veeck LL and Schlegel PN: Controlled comparison of percutaneous and microsurgical sperm retrieval in men with obstructive azoospermia Hum Reprod 1998, 13 (11):3086-3089

13. Palermo GD, Schlegel PN, Colombero LT et al.:Aggressive sperm immobilization prior to intracytoplasmic sperm injection with immature spermatozoa improves fertilization and pregnancy rates. Hum Reprod 1996;11: 1023-1029

14. Schlegel PN: Microsurgical techniques of epididymall and testicular sperm retrieval. In Marc Goldstein (Ed.): Surgery for Male Infertility -Atlas of the Urologic Clinic of North America. pp. 109- 129, 1999 W.B. Saunders Company, Philadelphia

15. Schlegel PN and Su LM.: Physiology consequences of testicular sperm extraction. Hum Reprod 1997, 12:1688-1692

16. Fiedler S, Raziel A, Strassburger D. et al.: Testicular sperm extraction by percutaenous fine needle sperm aspiration compared with testicular sperm extraction by open biopsy in men ith non-obstructive azoopsermia. Hum Reprod 1997, 12:1488-1493

17. Devroey P, Liu J, Nagy Z, Goossens A et al.: Pregnancies after testicular sperm extraction and intracytoplasmic sperm injection (ICSI) in non-obstructive azoospermia. Hum Reprod 1995;10:1457-1460.

18. Schlegel PN: Testicular sperm extraction: microdissection improves sperm yield with minimal tissue excision. Hum Reprod 1999, 14:131-135

19. Schlegel PN and Li, PS: Microdissection TESE: Testicular sperm retrieval in non-obstructive azoospermia. Video and abstract ( V-16) presented at the 94th annual meeting of American Urologic Association, May 1-6, 1999, Dallas, TX

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