Male infertility and intracytoplasmic sperm injection (ICSI)
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Male infertility and intracytoplasmic sperm
injection (ICSI)
Alastair J Campbell and D Stewart Irvine
MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, Edinburgh, UK
Micro-assisted fertilization in the form of intracytoplasmic sperm injection (ICSI)
has truly revolutionised the treatment options for couples with impaired semen
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
quality, and those with both obstructive and non-obstructive azoospermia. In
general, the major issues which relate to the success of ICSI are those related to
the success of conventional IVF, and the high multiple pregnancy rate remains a
major cause for concern. There is growing evidence that the short-term health
of ICSI offspring is relatively unremarkable, but our growing understanding of
the genetic basis of much of male subfertility and of the impaired genomic
integrity which characterises the oligozoospermic phenotype indicate a cautious
approach to the longer term health of ICSI offspring.
Infertility remains a common problem causing significant psychological
distress to those couples affected, who are increasingly seeking medical
advice. The substantial contribution of reproductive dysfunction in the
male partner to this infertility has been highlighted, and the development
of micro-assisted fertilization techniques, principally intracytoplasmic
sperm injection (ICSI), in the context of assisted conception has revol-
utionised the management of couples with so-called male factor infertility.
This article focuses on the diagnosis and causes of male infertility and the
development of ICSI to help such couples.
Infertility is commonly defined as the failure of conception after at least
12 months of unprotected intercourse1; however, accurate assessment of
the prevalence of infertility has always been difficult because of the
scarcity of large-scale population based studies2'3. Estimates suggest that
some 14-17% of couples may be affected at some time in their reprod-
uctive lives4"5, with recent European data suggesting that as many as one
in four couples may experience difficulties in conceiving6.
Correspondence to.
Dr D Stewart Irvine,
MRC Human Reproductive Contribution of the male partner to infertility
Sciences Unit Centre for
Reproductive Biology,
37 Chalmers St. The accurate diagnosis of male infertility is fraught with problems and,
Edinburgh EH3 9ET, UK therefore, establishing the extent of the male partner's contribution to
British Medical Bulletin 2000, 56 (No 3) 616-629 O The British Council 2000Male infertility and ICSI
infertility is difficult. The majority of studies of the epidemiology and
aetiology of male infertility have used the criteria of semen quality
devised by the World Health Organization 7 " 9 . However, a significant
proportion of men with a normal semen analysis according to these
criteria will be infertile because of defective sperm function10'11, whilst a
proportion of men with abnormal 'WHO' semen parameters will have
normal sperm function12-13. Hence, most studies use descriptive as
opposed to functional diagnostic criteria, and it is becoming clear from
recent studies on semen quality in relation to the achievement of
spontaneous pregnancy that these descriptive criteria may be in urgent
need of revision14. Despite these shortcomings, numerous workers have
concluded that the single most common factor contributing to infertility
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
is abnormal semen quality5'6'15"19.
Diagnosis and classification of 'male infertility'
From the above, it can be seen that a major obstacle to the understanding
and, therefore, treatment of male infertility is its accurate detection. It is
important to emphasise the value of a proper clinical history and
examination, as few positive diagnoses in clinical andrology can be made
on the examination of semen samples alone20. Whilst the WHO has
devised a diagnostic classification of male infertility to introduce
standardisation and facilitate multi-centre research, recent advances in
understanding the genetic causes of male infertility argue for a review of
the current classification21"25. Diagnosis is traditionally based on criteria of
semen quality promulgated by internationally recognised guidelines9-26,
which incorporate information on ejaculate volume, sperm concentration,
graded sperm motility and morphological appearance. This complex
assessment is subject to a range of shortcomings which might be expected
to limit its diagnostic value. Many attributes of semen quality examined
may be subjective in interpretation, although the recent introduction of
quality control into routine diagnostic laboratory andrology practice
should serve to limit inconsistencies in values between different
laboratories27"29. Additionally, marked interejaculate variation in semen
quality within one mdividual is well recognised, and requires the
assessment of multiple samples for diagnostic purposes8*30"31. Lastly, it has
become apparent that there is substantial geographical variation in human
semen quality32, so while the most recent WHO guidelines provide
reference ranges for 'normal' values, these are not well evidence-based and
highlight the importance of individual laboratories establishing normal
values for their own local populations.
Given the difficulties which beset the meaningful diagnosis of 'male
infertility' it is perhaps unsurprising that progress in understanding its
British Medical Bulletin 2000,56 (No 3) 617Human reproduction: pharmaceutical and technical advances
aetiology has been slow7 and that effective treatments are few33. The
clear exception to this is the application of techniques of micro-assisted
fertilization, principally intracytoplasmic sperm injection (ICSI), in the
context of assisted conception, which have revolutionised the
management of couples with male factor problems.
IVF and male infertility
Early developments in in vitro fertilization (IVF) focused on couples with
female factor infertility and particularly women suffering from bilateral
tubal occlusion34. Conventional IVF rapidly became established as an
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
effective treatment option for couples with tubal disease and with
unexplained infertility35; however, it soon became apparent that it yielded
generally poor pregnancy rates for couples with male factor infertility3*"38.
Tournaye et aP6, for example, compared in vitro fertilization and embryo
transfer (IVF-ET) in a group of couples with male infertility and a similar
group with tubal infertility. In cases of male infertility, more oocytes were
recovered but fewer oocytes were fertilized, fewer embryo transfers were
performed, the average number of embryos per transfer was lower and the
total pregnancy rate per cycle was also lower at 12.8% versus 22.9%.
They concluded that male infertility could be treated by IVF-ET, but that
the results were disappointing when compared to a control group with
normal spermatozoa. Although there was much discussion in the literature
on the fine-tuning of the IVF procedure for couples with problems in the
male partner39, management options for couples with poor semen quality
remained very limited until the breakthrough of effective micro-assisted
fertilization in 1992 40 .
Micro-manipulation techniques
Although the successful clinical application of techniques of micro-
assisted fertilization took place some 14 years after the first successful
human in vitro fertilization34, animal experimentation with micro-
assisted fertilization had in fact pre-dated human IVF41'42. In early
human studies, a range of approaches was initially explored.
Partial zona dissection
Partial zona dissection (PZD) was the first micromanipulation technique
studied in animal models with clinical intent43, and early reports in
human practice of clinical pregnancies were encouraging44-45, suggesting
618 British Medical Bulletin 2000;S6 (No 3)Male infertility and ICSI
that monospermic fertilization and cleavage rates could be doubled by
these approaches. However, concerns existed over the risk of poly-
spermy, along with doubts about appropriate case selection4*.
Sub zonal insemination
Sub zonal insemination (SUZI) involves the injection of spermatozoa into the
perivitelline space and, again, initial reports of its use were encouraging47'48,
although other groups found the technique to be less successful49'50.
Intracytoplasmic sperm injection
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
The developments in human micro-assisted fertilization culminated in
ICSI, with the first human pregnancies resulting from this technique being
described by the Brussels group in 199240. This approach involves
injection of a single spermatozoon directly into the cytoplasm of the
oocyte through the intact zona pellucida, and it very soon became
apparent that this technique produced superior results to PZD or SUZI,
with pregnancy rates of 22% per started cycle being reported51"52. Indeed,
such has been the success of ICSI that commentators have been moved to
suggest that it might be considered the treatment of choice for all cases
where in vitro conception is indicated53. Verheyen et alSA reported on a
controlled comparison of conventional IVF and ICSI in patients with
asthenozoospermia (which they defined asHuman reproduction: pharmaceutical and technical advances
before the technology was applied to the significant numbers of men who
present with no sperm in their ejaculates. Amongst men with obstructive
azoospermia, attention focused on spermatozoa derived from the
epididymis. The first pregnancies achieved with epididymal sperm were
described using conventional IVF57-58. However, fertilisation rates were
low, so whilst it was established that sperm from the epididymis had a
degree of functional competence, this was limited59-60, and animal experi-
mentation suggested that micro-assisted fertilization was likely to be
beneficial42-61. Initially, the use of SUZI was described62-63, but this was
rapidly replaced in clinical practice by ICSI64'65, which achieved very
satisfactory success rates.
As a consequence of the successful use of epididymal spermatozoa m
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
ICSI, techniques have been described to facilitate the surgical retrieval of
spermatozoa66'67. The major approaches include microsurgical epididymal
sperm aspiration (MESA), and percutaneous epididymal sperm aspiration
(PESA). MESA mvolves a formal scrotal exploration, is commonly
performed under general anaesthetic, and hence is a significant surgical
intervention68. A major advantage of this technique is that it permits full
scrotal examination and, therefore, has diagnostic power. The number of
spermatozoa retrieved is high, which facilitates cryopreservation69 and, if
indicated, it can be combined with definitive reconstructive surgery, such
as vaso-vasostomy or epididymo-vasostomy70. PESA is a widely used tech-
nique which is less invasive, can be performed under local anaesthesia71"73,
and can be performed repeatedly74. PESA provides less diagnostic
information, and the yield of spermatozoa may be lower, with one recent
review suggesting that at least 20% of attempts at PESA are unsuccessful
and require resort to MESA66. It has also been argued that, in patients
with presumed obstructive azoospermia, direct testicular fine needle
aspiration (TFNA) may be the procedure of choice67.
ICSI with testicular spermatozoa
In contrast to the position in men with obstructive azoospermia, amongst
men with non-obstructive azoospermia attention naturally focuses on the
testis as a site for sperm recovery. With the availability of ICSI, it has
become clear that non-obstructive azoospermia is a very heterogeneous
condition, and that testicular histology is similarly heterogeneous, with foci
of apparently normal spermatogenesis adjacent to seminiferous tubules
devoid of germ cells75. These observations led to attempts at the surgical
recovery of sperm from men with non-obstructive azoospermia, and the
successful achievement of pregnancies76. Since these exciting initial
observations, surgical sperm recovery from men with non-obstructive
azoospermia has become a routine part of clinical infertility practice77"81
620 British Medical Bulletin 2000,56 (No 3)Male infertility and ICSI
and, as with the epididymis, cryopreservation of testis derived spermatozoa
has also become routine82. A recent review concluded that surgical sperm
recovery would be successful in some 4 8 % of men with non-obstructive
azoospermia66.
Various approaches to the surgical recovery of sperm from the testis have
been described, both in the context of obstructive and non-obstructive
azoospermia. Testicular sperm aspiration (TESA) is a simple percutaneous
aspiration technique, performed under local anaesthetic, and which has a
high success rate of sperm retrieval in those men with normal
spermatogenesis. The advantages of TESA are its simplicity, quickness and
non-invasiveness. Testicular sperm extraction (TESE) on the other hand
mvolves an open excisional biopsy, equivalent to a diagnostic biopsy.
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
Sperm are extracted using either mincing techniques or enzymatic digestion
to disrupt the tissue and allow seminiferous tubules to release
spermatozoa. TESE also allows cryopreservation of tissue. Girardi and
Schlegel66 and Tournaye67 in recent reviews of the subject have argued that
in men with non-obstructive azoospermia, surgical access to the testis is
required, since pockets of spermatogenesis are isolated, and larger or
multiple biopsies are more often needed. This view has been supported by
recent comparative studies in which TESE was required in almost 80% of
men with non-obstructive azoospermia83.
Undoubtedly, one of the major problems confronting the process of
surgical sperm recovery from men with non-obstructive azoospermia is the
fact that there are currently no good predictors of which patients will have
sperm recovered successfully, and which will not84. Against this back-
ground, a number of groups have argued that surgical recovery of sperm
from the testis coupled with cryopreservation should precede ovarian
stimulation in the female partner85'86.
For those men m whom mature spermatozoa cannot be recovered, there
is currently interest in the possibility of using less mature cells, commonly
elongating or round spermatids, to achieve fertilization87. Work in animal
models has suggested that this may be a viable approach88-89, and there are
a number of clinical case reports m the literature90-91. At the present time,
however, uncertainties over the safety92 and efficacy of this approach
should confine its use to properly designed clinical trials.
Success rates of ICSI
ICSI has become well established as an effective form of treatment for
couples with male factor infertility. In the last year for which data are
available (1997/98) the UK's Human Fertilization and Embryology
Authority reported 9295 cycles of ICSI, alongside 24,889 cycles of IVF
- in other words, some 27% of assisted conception treatment in the UK
British Medical Bulletin 2000,56 (No 3) 621Human reproduction: pharmaceutical and technical advances
is for severe male factor infertility. In the same year, the reported live
birth rate for ICSI was 20.7% per cycle compared to 14.9% for IVF. In
keeping with the major issues in assisted conception in general, the
multiple birth rate was high at over 2 5 % , and the age of the female
partner was a major determinant of success, with a woman in her early
thirties achieving a 20-25% per cycle success rate, dropping to 5% or
less for a woman over the age of 40 years93.
Tarlatzis recently reviewed the world-wide experience of ICSP4. He
noted that over the 3 year period (1993-1995), the number of centres
undertaking ICSI in Europe increased from 35 to 101, and the total
number of ICSI cycles per year rose from 3157 to 23,932. The incidence
of oocytes damaged by the procedure was low (< 10%), and the
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
fertilization rates obtained with ejaculated, epididymal, and testicular
spermatozoa for 1995 were 64%, 62%, and 52%, respectively. Ultimately,
between 86-90% of couples achieved embryo transfer, and the viable
pregnancy rate was 2 1 % for ejaculated, 22% for epididymal, and 19% for
testicular sperm, with an incidence of multiple gestations of 29%, 30%,
and 38%, respectively. It was noteworthy that no difference was found in
ICSI results concerning the aetiology of azoospermia; for example,
obstructive (congenital or acquired) or non-obstructive. The Brussels group
have recently reviewed their own data on ICSI outcomes95 in a group of
Belgian couples, aged less than 37 years, who had their first ICSI cycle
between 1992/93. The per cycle delivery rate was high at 3 1 % , but the real
cumulative pregnancy rate was 60% after 6 cycles of treatment. Again,
female age had a powerful effect on success rates.
Outcomes of ICSI
Given that ICSI is effective, is it also safe? The rapid development of micro-
assisted conception techniques and the wide-spread use of in ICSI in
alleviating male infertility have raised concerns about the health of the
offspring. ICSI, by directly injecting individual spermatozoa into a mature
oocyte bypasses the natural physiological processes of normal sperm
selection, raising concerns over the potential risk of congenital
malformations and genetic defects in children born after ICSI. It has also
stimulated debate regarding associations between obstetric and perinatal
outcome and type of conception. Recent work showing that poor quality
semen tends to contain gametes with compromised DNA integrity96, but
that this does not compromise its fertilizing ability at ICSP7 further
highlights the importance of interest in the area of ICSI outcome.
Without doubt, the most thorough and detailed follow-up studies of ICSI
offspring have been those orchestrated by the Brussels group98 who have
undertaken a prospective follow-up study of 1987 children born after ICSI,
622 British Medical Bulletin 20OO-.S6 {No 3)Male infertility and ICSI
aiming to compile data on karyotypes, congenital malformations, growth
parameters and developmental milestones. They were able to collect data
on 1699, 91 and 118 children born after ICSI with ejaculated, epididymal
and testicular spermatozoa, respectively, as well as on 79 children born
from cryopreserved ICSI embryos. Of 1082 karyotypes determined by
prenatal diagnosis, 1.66% (18) were abnormal de novo (nine each of
autosomal and sex chromosomal aberrations), and 0.92% (10) were
inherited structural aberrations. Of these, nine (eight balanced structural
aberrations and one unbalanced trisomy 21) were transmitted from the
father. Forty-six major malformations (2.3%) were observed at birth.
Seven malformations, observed by prenatal ultrasound, were terminated.
Twenty-one (1.1 %) stillbirths, including four with major malformations,
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
occurred later than 20 weeks of pregnancy.
In Denmark, a national cohort study of 730 infants born after ICSP9
included all clinical pregnancies obtained after ICSI registered in Denmark
between January 1994 and July 1997 at five public and eight private
fertility clinics. Only 183 women (28.5%) underwent prenatal diagnosis,
resulting in 209 karyotypes with seven (3.3%) chromosome aberrations.
Six major chromosomal abnormalities (2.9%) and one inherited structural
chromosome aberration (0.5%) were found, but no sex chromosome
aberrations. The frequency of multiple birth, Caesarean section rate,
gestational age, preterm birth, and birth weight were comparable with
previous studies. The perinatal mortality rate was 13.7 per 1000 children
born with a gestational age of 24 weeks or more. In 2.2% of the live-born
infants, and in 2.7% of all infants, the parents reported major birth defects.
Minor birth defects were found in nine live-born infants (1.2%).
Most recently, Wennerholm et alm studied the incidence of congenital
malformations in a complete cohort of 1139 infants, 736 singletons, 200
sets of twins and one set of triplets born after ICSI. The number of infants
with an identified anomaly was 87 (7.6%), 40 of which were minor. The
incidence of malformations in children born after ICSI was compared with
all births in Sweden using data from the Swedish Medical Birth Registry
and the Registry of Congenital Malformations. For ICSI children, the odds
ratio (OR) for having any major or minor malformation was 1.75 (95%
confidence interval (CI) 1.19-2.58) after stratification for delivery hospital,
year of birth and maternal age. If stratification for singletons/twins was
also done, the OR was reduced to 1.19 (95% CI, 0.79-1.81). The
increased rate of congenital malformations is thus mainly a result of a high
rate of multiple births. Of interest, the only specific malformation which
was found to occur in excess in children born after ICSI was hypospadias
(relative risk 3.0, exact 95% CI, 1.09-6.50). The same group examined the
obstetric outcome of pregnancies after ICSI101. Deliveries occurred in
75.9% and early spontaneous abortion, late spontaneous abortion and
ectopic pregnancy in 21.4%, 1.0% and 1.2% of pregnancies, respectively.
British Medical Bulletin 2000,56 (No 3) 623Human reproduction: pharmaceutical and technical advances
Multiple birth occurred in 21.3% (almost all twins) of deliveries, and
preterm birth occurred in 15.7% of all deliveries. Preterm birth was not
related to sperm origin or quality but was related to multiple birth. The
prematurity rate was 8.4%, 42.3% and 100% for singletons, twins and
triplets, respectively. The perinatal mortality rate was 11.7 per 1000 born
infants; 7.3% of infants had a malformation, 40 of which were minor.
They concluded that the obstetric outcome of ICSI pregnancies was similar
to that of conventional IVF and was not influenced by sperm origin or
quality. The high incidence of multiple births remains the major concern.
Other groups have reached similar conclusions102.
In other words, as the database of ICSI offspring grows larger, the
available evidence on the short-term health of these offspring is generally
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
reassuring. It is important, however, to appreciate the important role that
a genetic aetiology plays in the origins of much male subfertility, and the
ability of ICSI to promote the transgenerational transmission of genetic
defects causing gametogenic failure. It seems clear that male, but not
female, fertility problems show a distinct pattern of familial aggregation,
and that couples with male infertility have fewer siblings than fertile
controls103. The significantly increased risk of chromosomal abnormalities
in men with impaired semen quality21 is easily managed by the appropriate
investigation and counselling which are required prior to treatment104.
Some groups have even advocated chromosomal studies on both
partners105. It is less easy to be certain how to respond to the available
evidence on microdeletions of the Y chromosome in men with severely
impaired semen quality22'24'25'106. The strength of the association between Y
chromosome deletions and severely impaired semen quality is impressive,
and it is increasingly suggested that these lesions may result in progression
from oligozoospermia to azoospermia over time107. In a recent study, Pryor
et a/106 found deletions in 7% of infertile men, and in only 2 % of normal
men, but observed no clear relationships between the size and location of
the deletions and the severity of the spermatogenic failure. Moreover, it is
clear that these genetic deletions, if present, can be transmitted to offspring
via ICSI107'108. On the basis of this evidence, some authorities now advocate
screening of men for Y chromosome microdeletions prior to ICSI, and
advocate testing of offspring and reproductive monitoring for those found
to have inherited deletions.
References
1 Rowe PJ, Comhaire FH, Hargreave TB, Mellows HJ WHO Manual for the Standardized
Investigation and Diagnosis of the Infertile Couple. Cambridge: Cambridge University Press,
1993
2 Greenhall E, Vessey M The prevalence of subfertility: a review of the current confusion and a
report of two new studies. Fertd Steril 1990; 54: 978-83
3 Thonneau P, Spira A. Prevalence of infertility: International data and problems of measurement.
EurJ Obstet Gynecol Reprod Btol 1990; 38: 43-52
624 British Medical Bulletin 2000,56 (No 3)Male infertility and ICSI
4 Templeton A, Fraser C, Thompson B. The epidemiology of infertility in Aberdeen. BMJ 1990;
301: 148-52
5 Hull MGR, Glazener CMA, Kelly NJ et al. Population study of causes, treatment and outcome
of infertility. BMJ 1985; 291: 1693-7
6 Schmidt L, Munster K, Helm P Infertility and the seeking of infertility treatment m a
representative population. Br J Obstet Gynaecol 1995; 102: 978-84
7 Irvine DS. Epidemiology and aetiology of male infertility. Hum Reprod 1998, 13 (Suppl 1):
33-44
8 World Health Organization Laboratory Manual for the Examination of Human Semen and
Semen-Cervical Mucus Interaction. Singapore: Press Concern, 1980
9 World Health Organization. WHO Laboratory Manual for the Examination of Human Semen
and Sperm-Cervical Mucus Interaction. Cambridge: Cambridge University Press, 1999
lOAitken RJ, Best FS, Richardson DW et al. An analysis of sperm function in cases of unexplained
infertility: conventional criteria, movement characteristics, and fertilizing capacity. Fertil Stertl
1982, 38- 212-21
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
11 Aitken RJ, Irvine DS, Wu FC. Prospective analysis of sperm-oocyte fusion and reactive oxygen
species generation as criteria for the diagnosis of infertility. Am J Obstet Gynecol 1991; 164:
542-51
12Aitken RJ Diagnostic value of the zona-free hamster oocyte penetration test and sperm
movement characteristics in oligozoosperrma. Int J Androl 1985; 8: 348-56
13Aitken RJ, Best FSM, Richardson DW, Djahanbakhch O, Templeton A, Lees MM. An analysis
of semen quality and sperm function in cases of oligozoosperrma Fertil Steril 1982; 38: 705-11
14Bonde JP, Ernst E, Jensen TK et al. Relation between semen quality and fertility: a population-
based study of 430 first-pregnancy planners [see comments]. Lancet 1998; 352: 1172-7
15Cates W, Farley TMM, Rowe PJ Worldwide patterns of lnfertihty: is Africa different? Lancet
1985, ii 596-8
16 Collins JA, Wnxon W, Janes LB, Wilson EH. Treatment-independent pregnancy among infertile
couples. N EnglJ Med 1983; 309: 1201-6
17Haxton MJ, Black WP The aetiology of infertility in 1162 investigated couples. Cltn Exp Obstet
Gynecol 1987; XTV: 75-9
18 Randall JM, Templeton AA. Infertility the experience of a tertiary referral centre. Health Bull
1991; 49: 48-53
19Thonneau P, Marchand S, Tallec A et al. Incidence and main causes of infertility in a resident
population (1 850 000) of three French regions (1988-1989). Hum Reprod 1991; 6: 811-6
20 Cummins JM, Jequier AM. Treating male infertility needs more clinical andrology, not less. Hum
Reprod 1994; 9: 1214-9
21Hargreave TB. Genetics and male infertility. Curr Opm Obstet Gynecol 2000; 12: 207-19
22Qureshi SJ, Ross AR, Ma K et al. Polymerase chain reaction screening for Y chromosome
microdeletions: a first step towards the diagnosis of genetically-determined spermatogenic
failure in men. Mol Hum Reprod 1996; 2: 775-9
23Vogt PH, Edelmann A, Kirsch S et al Human Y chromosome azoospermia factors (AZF)
mapped to different subregions in Yqll. Hum Mol Genet 1996; 5. 933-43
24Ma K, Sharkey A, Kirsch S et al Towards the molecular localisation of the AZF locus: mapping
of microdeletions m azoospermic men within 14 subintervals of interval 6 of the human Y
chromosome. Hum Mol Genet 1992; 1- 29-33
25Vogt P, Chandley AC, Hargreave TB, Keil R, Ma K, Sharkey A. Microdeleaons in interval 6 of
the Y chromosome of males with ldiopathic sterility point to disruption of AZF, a human
spermatogenesis gene. Hum Genet 1992; 89: 491—6
26World Health Organization. WHO Laboratory Manual for the Examination of Human Semen
and Semen-Cervical Mucus Interaction. Cambridge: Cambridge University Press, 1992
27 Cooper TG, Neuwinger J, Bahrs S, Neischlag E Internal quality control of semen analysis. Fertil
Steril 1992; 58: 172-8
28Matson PL. External quality assessment for semen analysis and sperm antibody detection: results
of a pilot scheme. Hum Reprod 1995; 10: 620-5
29Neuwinger J, Nieschlag E. External quality control in the andrology laboratory: an experimental
mulncenter trial. Fertil Steril 1990; 54: 308-14
British Medical Bulletin 2000;56 (No 3) 625Human reproduction: pharmaceutical and technical advances
30Schwartz D, Laplanche A, Jouannet P, David G. Within-subject variability of human semen in
regard to sperm count, volume, total number of spermatozoa and length of abstinence. /
Reprod Fertil 1979; 57: 391-5
31Mallidis C, Howard EJ, Baker HW. Variation of semen quality in normal men. Int J Androl
1991; 14:99-107
32Irvine DS. Changes in human male reproductive health. In: Glover TD, Barratt CLR. (Eds) Male
Fertility and Infertility. Cambridge: Cambridge University Press, 1999; 128-46
33O'Donovan PA, Vandekerckhove P, Lilford RJ, Hughes E. Treatment of male infertility- is it
effective? Review and meta analyses of published randomised controlled trials Hum Reprod
1993; 8. 1209-22
34Steptoe PC, Edwards RG. Birth after the reimplantation of a human embryo. Lancet 1978; u:
366
35 Hull MG, Joyce DN, McLeod FN, Ray BD, McDermott A. Human in vitro fertilisation, in vivo
sperm penetration of cervical mucus, and unexplained infertility. Lancet 1984, ii. 245-6
36Tournaye H, Devroey P, Camus M et al. Comparison of in vitro fertilization in male and tubal
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
infertility: a 3 year survey. Hum Reprod 1992; 7: 218-22
37Cohen J, Edwards R, Fehilly C et al. In vitro fertilization: a treatment for male infertility. Fertil
Steril 1985; 43 422-32
38Mahadevan MM, Trounson AO, Leeton JF. The relationship of tubal blockage, infertility of
unknown cause, suspected male infertility, and endometriosis to success of m vitro fertilization
and embryo transfer. Fertil Steril 1983; 40: 755-62
39Ord T, Patrizio P, Balmaceda JP, Asch RH Can severe male factor infertility be treated without
micromanipulation? Fertil Steril 1993; 60: 110-5
40Palermo G, Jons H, Devroey P, Van Steirteghem AC. Pregnancies after lnrracytoplasmic injection
of single spermatozoon into an oocyte. Lancet 1992; 340: 17-8
41Uehara T, Yanagimachi R Microsurgical injection of spermatozoa into hamster eggs with
subsequent transformation of sperm nuclei into male pronuclei. Biol Reprod 1976; 15: 467-70
42Uehara T, Yanagimachi R. Behaviour of nuclei of testicular, caput and cauda epididymal
spermatozoa injected into hamster eggs Btol Reprod 1977; 16: 315-21
43 Gordon JW, Talansky BE. Assisted fertilization by zona drilling: a mouse model for the
correction of oligozoospermia / Exp Zool 1986; 239: 347—54
44 Cohen J, Maker H, Wright G, Kort H, Massey J, Mitchell D. Partial zona dissection of human
oocytes when failure of zona pelluada penetration is anticipated. Hum Reprod 1989, 4: 435-42
45Malter HE, Cohen J. Partial zona dissection of the human oocyte: a nontraumaac method using
micromanipulation to assist zona pellucida penetration. Fertil Steril 1989, 51: 139-48
46 Tucker MJ, Bishop FM, Cohen J, Wiker SR, Wright G. Routine application of partial zona
dissection for male factor infertility. Hum Reprod 1991; 6- 676-81
47Fishel S, Antinon S, Jackson P, Johnson J, Rinaldi L. Presentation of six pregnancies established
by sub-zonal insemination (SUZI). Hum Reprod 1991, 6 124-30
48Fishel S, Jackson P, Antinon S, Johnson J, Grossi S, Versaci C. Subzonal insemination for the
alleviation of infertility. Fertil Steril 1990; 54: 828-35
49 Wolf JP, Ducot B, Kunstmann JM, Frydman R, Jouannet P. Influence of sperm parameters on outcome
of subzonal insemination in the case of previous rVF failure. Hum Reprod 1992, 7 1407-13
50Gordts S, Garcia G, Vercruyssen M, Roziers P, Campo R, Swinnen K. Subzonal insemination: a
prospective randomized study in patients with abnormal sperm morphology Fertil Steril 1993;
60: 307-13
51 Van Steirteghem AC, Liu J, Jons H et al. Higher success rate by intracytoplasmic sperm injection
than by subzonal insemination. Report of a second senes of 300 consecutive treatment cycles.
Hum Reprod 1993; 8: 1055-60
52Abdalla H, Leonard T, Pryor J, Everest D. Comparison of SUZI and ICSI for severe male factor.
Hum Reprod 1995; 10: 2941-4
53Fishel S, Aslam I, Lisi F et al. Should ICSI be the treatment of choice for all cases of in vitro
conception? Hum Reprod 2000,15: 1278-83
54Verheyen G, Tournaye H, Staessen C, De Vos A, Vandervorst M, Van Steirteghem A. Controlled
comparison of conventional in vitro fertilization and lntracytoplasmic sperm injection in
panents with asthenozoospernua Hum Reprod 1999; 14: 2313-9
626 British Medical Bulletin 2000;56 (No 3)Male infertility and ICSI
55Staessen C, Camus M, Clasen K, De Vos A, Van Steirteghem A Conventional in vitro
fertilization versus lntracytoplasmic sperm injection in sibling oocytes from couples with tubal
infertility and normozoospermic semen. Hum Reprod 1999; 14: 2474-9
56 van Rumste MM, Evers JL, Farquhar CM, Blake DA. Intra-cytoplasmic sperm injection versus
partial zona dissection, subzonal insemination and conventional techniques for oocyte
insemination during in vitro fertilisation. Cochrane Database of Systematic Reviews 2000;
CD001301
57Silber SJ, Balmaceda J, Borrero C, Ord T, Asch R. Pregnancy with sperm aspiration from the
proximal head of the epididymis a new treatment for congenital absence of the vas deferens. Fertil
Stertl 1988, 50: 525-8
58 Temple-Smith PD, Southwick GJ, Yates CA, Trounson AO, de Kretser DM. Human pregnancy
by in vitro fertilization (FVF) using sperm aspirated from the epididymis. / In Vitro Fertil
Embryo Trans 1985; 2: 119-22
59 Rojas FJ, La AT, Ord T et al Penetration of zona-free hamster oocytes using human sperm
aspirated from the epididymis of men with congemtal absence of the vas deferens: comparison
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
with human m vitro fertilization. Fertil Stenl 1992; 58 1000-5
60 Davis RO, Overstreet JW, Asch RH, Ord T, Silber SJ. Movement characteristics of human
epididymal sperm used for fertilization of human oocytes in vitro. Fertil Stenl 1991; 56:
1128-35
61Wazzan WC, Gwatkin RB, Thomas Jr AJ. Zona drilling enhances fertilization by mouse caput
epididymal sperm. Mol Reprod Dev 1990; 27: 332-6
62Soong YK, Lai YM, Chang SY, Wang ML, Chang MY, Lee CL. A successful pregnancy after
subzonal insertion with epididymal sperm and coculture on Vero cell monolayer. Fertil Sterd
1993, 59: 1308-10
63Jansen RP, Golovsky D, Lippi J, Mortimer D. Pregnancy from subzonally micrornjected
epididymal spermatozoa. Med] Aust 1993; 158: 646-7
64 Silber SJ, Nagy ZP, Liu J, Godoy H, Devroey P, Van Steirteghem AC. Conventional in vitro
fertilization versus lntracytoplasmic sperm injection for patients requiring microsurgical sperm
aspiration. Hum Reprod 1994, 9: 1705-9
65 Liu J, Lissens W, Silber SJ, Devroey P, Liebaers I, Van Steirteghem A. Birth after preimplantation
diagnosis of the cystic fibrosis delta F508 mutation by polymerase chain reaction in human
embryos resulting from lntracytoplasmic sperm injection with epididymal sperm. JAMA 1994;
272: 1858-60
66 Girardi SK, Schlegel PN. Techniques for sperm recovery in assisted reproduction Reprod Med
Rev 1999, 7. 131-9
67Tournaye H Surgical sperm recovery for lntracytoplasmic sperm injection: which method is to
be preferred?. Hum Reprod \999; 14 (Suppl 1): 71-81
68 Collins GN, Cntchlow JD, Lau MW, Payne SR. Open versus closed epididymal sperm retrieval in
men with secondarily obstructed vasal systems - a preliminary report [see comments]. Br J Urol
1996; 78: 437-9
69Tournaye H, Merdad T, Silber S et al. No differences in outcome after rntracytoplasmic sperm
injection with fresh or with frozen-thawed epididymal spermatozoa. Hum Reprod 1999; 14: 90-5
70Heidenreich A, Altmann P, Engelmann UH. Microsurgical vasovasostomy versus microsurgical
epididymal sperm aspiration/testicular extraction of sperm combined with lntracytoplasmic
sperm injection. A cost-benefit analysis. Eur Urol 2000; 37: 609-14
71Tsingons M, Pelekanos M, Beski S, Gregorakis S, Foster C, Craft IL. Cumulative experience of
percutaneous epididymal sperm aspiration (PESA) with lntracytoplasmic sperm injection. /
Assist Reprod Genet 1996; 13: 315-9
72Tsingotis M, Pelekanos M, Yazdani N, Boulos A, Foster C, Craft EL. Simplified sperm retrieval
and lntracytoplasrruc sperm injection in patients with azoosj>ermia. Br J Urol 1995; 76: 765-8
73Gorgy A, Memru GI, Naumann N, Beski S, Bates S, Craft IL. The efficacy of local anaesthesia
for percutaneous epididymal sperm aspiration and testicular sperm aspiration. Hum Reprod
1998, 13: 646-50
74Rosenlund B, Westlander G, Wood M, Lundin K, Reismer E, Hillens|o T Sperm retrieval and
fertilization in repeated percutaneous epididymal sperm aspiration. Hum Reprod 1998; 13:
2805-7
British Medical Bulletin 2000,56 (No 3) 627Human reproduction: pharmaceutical and technical advances
75 Tournaye H, Staessen C, Lacbaers I et al. Testicular sperm recovery in rune 47,XXY Klinefelter
patients. Hum Reprod 1996; 11: 1644-9
76Silber SJ, Van Steirteghem AC, Liu J, Nagy Z, Tournaye H, Devroey P. High fertilization and
pregnancy rate after mtracytoplasmic sperm injection with spermatozoa obtained from testicle
biopsy. Hum Reprod 1995; 10: 148-52
77Mansour RT, Aboulghar MA, Serour GI, Fahmi I, Ramzy AM, Amin Y Intracytoplasmic sperm
injection using rrucrosurgically retrieved epididymal and testicular sperm Ferttl Stertl 1996; 65:
566-72
78 Tournaye H, Liu J, Nagy Z, Verheyen G, Van Steirteghem A, Devroey P. The use of testicular
sperm for intracytoplasmic sperm injection m patients with necrozoosperrrua. Fertil Steril 1996,
66: 331-4
79Silber SJ, Van Steirteghem A, Nagy Z, Liu J, Tournaye H, Devroey P. Normal pregnancies
resulting from testicular sperm extraction and intracytoplasmic sperm injection for
azoospermia due to maturation arrest. Ferttl Steril 1996; 66 110-7
80Kahraman S, Ozgur S, Alatas C et al Fertility with testicular sperm extraction and
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
intracytoplasmic sperm injection in non-obstructive azoospcrmic men. Hum Reprod 1996; 11:
756-60
81Schlegel PN, Palermo GD, Goldstein M et al. Testicular sperm extraction with intracytoplasmic
sperm injection for nonobstrucnve azoospermia. Urology 1997; 49: 435-40
82Oates RD, Mulhall J, Burgess C, Cunningham D, Carson R. Fertilization and pregnancy using
intentionally cryopreserved testicular tissue as the sperm source for intracytoplasmic sperm
injection in 10 men with non-obstructive azoospermia. Hum Reprod 1997; 12: 734—9
83 Mercan R, Urman B, Alatas Cetal. Outcome of tesncular sperm retrieval procedures in non-obstructive
azoospermia : percutaneous aspiranon versus open biopsy Hum Reprod 2000, 15: 1548—51
84Tournaye H, Verheyen G, Nagy P et al. Are there any predictive factors for successful testicular
sperm recovery in azoospermic patients' Hum Reprod 1997; 12: 80-6
85Ben-Yosef D, Yogev L, Hauser R et al. Testicular sperm retrieval and cryopreservation prior to
initiating ovarian stimulation as the first line approach in patients with non-obstructive
azoospermia. Hum Reprod 1999; 14: 1794-801
86Gianaroli L, Magh MC, Selman HA et al Diagnostic testicular biopsy and cryopreservaoon of
testicular tissue as an alternative to repeated surgical openings in the treatment of azoospermic
men. Hum Reprod 1999; 14: 1034-8
87Aitken RJ, Irvine DS. Fertilization without sperm. Nature 1996; 379: 493-5
88Ogura A, Matsuda J, Yanagimachi R Birth of normal young after electrofusion of mouse
oocytes with round spermands. Proc Natl Acad Set USA 1994; 91- 7460-2
89Kimura Y, Yanagimachi R. Mouse oocytes injected with testicular spermatozoa or round
spermatids can develop into normal offspring. Development 1995; 121: 2397-405
90Gianaroh L, Selman HA, Magli MC, Colpi G, Fornni D, Ferraretti AP. Birth of a healthy infant
after conception with round spermatids isolated from cryopreserved testicular tissue. Ferttl
Steril 1999; 72: 539-41
91A1-Hasani S, Ludwig M, Palermo I et al. Intracytoplasmic injection of round and elongated
spermatids from azoospermic panents: results and review Hum Reprod 1999; 14 (Suppl 1):
97-107
92Zech H, Vanderzwalmen P, Prapas Y, Lejeune B, Duba E, Schoysman R. Congenital
malformations after intracytoplasmic injection of spermatids. Hum Reprod 2000; 15: 969-71
93 Human Fertilization and Embryology Authority HFEA Annual Report 1999. London: HFEA,
1999
94Tarlatzis BC, Bill H. Intracytoplasmic sperm injection. Survey of world results. Ann N Y Acad
Sa 2000; 900: 336-44
95Osmanagaoglu K, Tournaye H, Camus M, Vandervorst M, Van Steirteghem A, Devroey P
Cumulative delivery rates after intracytoplasmic sperm injection: 5 year follow-up of 498
patients. Hum Reprod 1999; 14. 2651-5
96Imne DS, Twigg JP, Gordon EL, Fulton N, Milne PA, Aitken RJ. DNA integrity in human
spermatozoa: relationships with semen quality. / Androl 2000; 21: 33—44
97Twigg J, Irvine D, Aitken R. Oxidative damage to DNA in human spermatozoa does not
preclude pronucleus formation at ICSI Hum Reprod 1998; 13: 1864-71
628 British Medical Bulletin 2000,56 (No 3)Male infertility and ICSI
98Bonduelle M, Camus M, De Vos A et al. Seven years of intracytoplasmic sperm injection and
follow-up of 1987 subsequent children. Hum Reprod 1999; 14 (Suppl 1): 243-64
99 Loft A, Petersen K, Erb K et al. A Danish national cohort of 730 infants born after
intracytoplasmic sperm injection (ICSI) 1994-1997 Hum Reprod 1999; 14: 2143-8
100 Wennerholm UB, Bergh C, Hamberger L et al. Incidence of congenital malformations in
children born after ICSI Hum Reprod 2000, 15 944-8
101 Wennerholm UB, Bergh C, Hamberger L, Westlander G, Wikland M, Wood M. Obstetric
outcome of pregnancies following ICSI, classified according to sperm origin and quality Hum
Reprod 2000; 15: 1189-94
102 Govaerts I, Devreker F, Koenig I, Place I, Van den Bergh M, Englert Y. Comparison of
pregnancy outcome after intracytoplasmic sperm injection and in vitro fertilization. Hum
Reprod 1998; 13 1514-8
103 Meschede D, Lemcke B, Behre HM, De Geyter C, Nieschlag E, Horst J Clustering of male
infertility in the families of couples treated with intracytoplasmic sperm in)ecnon Hum Reprod
2000, 15- 1604-8
Downloaded from http://bmb.oxfordjournals.org/ by guest on September 23, 2015
104 Royal College of Obstetricians and Gynaecologists. The Management of Infertility in Tertiary
Care. London: RCOG, 1999
105 Peschka B, Leygraaf J, Van der Ven K et al Type and frequency of chromosome aberrations in
781 couples undergoing intracytoplasmic sperm injection Hum Reprod 1999; 14: 2257—63
106 Pryor JL, Kent-First M, Muallem A et al. Microdeletions in the Y chromosome of infertile men.
N EnglJ Med 1997; 336: 534-9.
107 Kamischke A, Gromoll J, Simoni M, Behre HM, NieschJag E Transmission of a Y
chromosomal deletion involving the deleted in azoospermia (DAZ) and chromodomain
(CDY1) genes from father to son through intracytoplasmic sperm injection: case report. Hum
Reprod 1999; 14. 2320-2
108 Page DC, Silber S, Brown LG. Men with infertility caused by AZFc deletion can produce sons
by intracytoplasmic sperm injection, but are likely to transmit the deletion and infertility. Hum
Reprod 1999; 14. 1722-6
British Medical Bulletin 2000,56 (No 3) 629You can also read
