Effects of hormonal treatment on the contralateral descended testis in unilateral cryptorchidism

Stereological study of testes following experimentally-induced unilateral cryptorchidism in rats

OBJECTIVE

Cryptorchidism is one of the main causes of infertility and can result in testicular cancer. This study aimed to present quantitative data on the damage caused by cryptorchidism using stereological analysis.

METHODS

Thirty newborn rats were randomly divided into control and experimental groups. The experimental group underwent surgery to induce unilateral cryptorchidism in the left testis, whereas the control group underwent a sham surgical procedure 18 days after birth. The testes were removed at designated time points (40, 63, and 90 days after birth) for stereological evaluation and sperm analysis. Total testicular volume, interstitial tissue volume, seminiferous tubule volume and length, and seminiferous epithelium volume and surface area were measured. Other parameters, such as sperm count, sperm morphology, and sperm tail length, were also examined.

RESULTS

Statistically significant differences (p<0.05) were observed between the experimental and the control groups at different ages regarding the volumes of various parameters, including the surface area of the germinal layer, the length of the seminiferous tubules, sperm count, and sperm morphology. However, no significant differences were observed in the epithelial volume and the sperm tail length of the groups.

CONCLUSION

Given the substantial effect of cryptorchidism on different testicular parameters, as well as the irreversible damage it causes in the testes, it is important to take this abnormality seriously to prevent these consequences.

Bibliometric analysis of scientific publications on cryptorchidism: Research hotspots and trends between 2000 and 2022

Background

Cryptorchidism is defined as failure of unilateral or bilateral testicular descent, which increases the risk of infertility and testicular carcinoma. Although there is much research on cryptorchidism, few studies have used the bibliometric analysis method. The purpose of this study was to conduct a comprehensive analysis of cryptorchidism from muti-dimensional perspectives to summarize the research hotspots and trends in cryptorchidism research.

Methods

Relevant studies on cryptorchidism were retrieved from the Web of Science Core Collection (WoSCC) database from 2000 to 2022. A comprehensive bibliometric analysis of cryptorchidism was performed by using the CiteSpace, Tableau Public, and VOSviewer software, including the annual distributions of publications, countries, authors, institutions, journals, references, and keywords.

Results

From January 1st, 2000 to May 17th, 2022, a total of 5023 papers concerning cryptorchidism were identified for analysis. The USA contributed the most publications (n = 1193) in this field, and the annual number of publications rose rapidly in China. The University of Melbourne published the largest number of papers (n = 131). "Hutson, John M." was the most core author ranked by publications (n = 51), and "Skakkebaek, Niels E." enjoyed the largest number of citations (4441). The JOURNAL OF UROLOGY published the largest number of papers (n = 225), while the average citations per publication of the 75 papers in HUMAN REPRODUCTION reached 62.38. Additionally, burstness analysis of references and keywords showed that cryptorchidism research was mainly focused on the exploration of the optimal mode of treatment for cryptorchidism, including hypogonadism such as Kallmann syndrome and Klinefelter syndrome.

Conclusion

Cryptorchidism has attracted continuous attention from the scientific community concerned. International collaboration in the field has witnessed significant growth in recent years and remains essential to further enhance collaborative efforts between scholars from different countries. In addition, the exploration of the optimal treatment modality for cryptorchidism, especially in the prevention of adult infertility, remains a major focus of future research. High-quality follow-up studies are also needed in the future. The pathogenesis (especially at the genetic level) and treatment of hypogonadism such as Kallmann syndrome and Klinefelter syndrome have attracted increasing attention recently, which may usher in some breakthroughs in coming years.

The positive predictive value of using fsh and Inhibin-B serum levels to diagnose gonadotropin insufficiency in bilateral cryptorchid boys is high

AIM OF STUDY

Despite early surgery, many boys with bilateral cryptorchidism at surgery have a reduced number of germ cells per tubular cross-section (G/T) in testicular biopsies and/or low inhibin-B with no elevated follicle-stimulating hormone (FSH) as expected based on a normal gonadotropin feed-back mechanism. Such boys have a high risk of later infertility because of insufficient gonadotropin stimulation and may benefit from adjuvant hormonal treatment. Testicular biopsies are not always wanted or accepted. The study aim was to investigate the value of a low inhibin-B and normal FSH to identify patients that might benefit from adjuvant hormonal treatment avoiding the need for testicular biopsy.

METHODS

A series of boys with cryptorchidism were evaluated with serum levels of inhibin-B and FSH in relation to G/T in testicular biopsies, which were compared to previously published age-matched normal control values.

RESULTS

A total of 365 boys who underwent bilateral orchidopexy between 0.4 and 7.8 (median: 2) years of age were included. Twenty-seven (7%) patients had increased FSH and low G/T, whereas 11 of these also had low inhibin-B indicating hypergonadotropic hypogonadism. Moreover, 85 (23%) patients between 0.75 and 7.5 (median: 2) years of age had both low G/T (median: 0.3) and low inhibin-B (median: 56 pg/ml) but normal FSH (median: 0.6 U/l) indicating a gonadotropin insufficiency. Three patients with normal FSH and low inhibin B had normal G/T.

DISCUSSION

Our study shows that if surgeons prefer to avoid testicular biopsies and only wish to rely on hormonal parameters (low inhibin-B and normal FSH) in order to diagnose a gonadotropin insufficiency as the cause of hypogonadism, they will identify only about 30% of such cases and overlook about 70% of patients sharing the same endocrinopathy. In addition, if surgeons treat patients for gonadotropin insufficiency only based on low inhibin-B and normal FSH they will solely treat patients with gonadotropin insufficiency and would not overtreat patients.

CONCLUSION

Adjuvant hormonal treatment was indicated by a gonadotropin insufficiency discerned in 23% of boys with bilateral cryptorchidism. Without histology, the clinicians are left with more difficult clinical judgments to identify patients for adjuvant hormonal treatment. The positive predictive value of low inhibin-B and normal FSH corroborated by low G/T was 0.97 (85/85 + 3), but the sensitivity was low (0.30).

Fertility of Cryptorchid Testis-An Unsolved Mistery

Cryptorchidism (undescended testis) is one of the most common diagnoses in the pediatric urologist office. Even in the modern era, there still are a lot of debates regarding the optimal time for surgery related to the expected results in relation with the testicular function, including fertility. The review below intends to clarify issues regarding the impact of cryptorchidism on testicular histology and function, semen analysis, the relation between hormonal and surgical treatment, future fertility, and paternity rate.

Bilateral versus unilateral cryptorchidism in nonobstructive azoospermia: Testicular sperm extraction outcomes

Cryptorchidism is one of the most frequent causes of nonobstructive azoospermia (NOA) in adulthood. Although it is well known that spermatogenesis is more impaired in bilateral than in unilateral cryptorchidism, previous studies have only described small cohorts or inhomogeneous population. Consequently, we analyzed a cohort of 225 men with only a history of cryptorchidism as sole etiopathogenetic factor for NOA, and compared testicular sperm extraction (TESE) outcomes between men with bilateral versus unilateral cryptorchidism. Our results show no difference in follicle-stimulating hormone (FSH) levels and testicular volumes between men with a history of bilateral cryptorchidism compared to unilateral cryptorchidism (median: 21.3 IU l⁻¹vs 19.3 IU l⁻¹, P = 0.306; and 7.2 ml vs 7.9 ml, P = 0.543, respectively). In addition, sperm retrieval rates were similar (66.2% vs 60.0%, P = 0.353). Using multivariate analysis, we have found that only a low inhibin B level (above the assay's detection limit) was positively associated with successful sperm retrieval (P < 0.05). Regarding intracytoplasmic sperm injection outcomes, we found that cumulative pregnancy rate and live birth rate per cycle were not statistically different between the two groups (17.4% vs 27.8%, P = 0.070; and 16.1% vs 26.4%, P = 0.067, respectively). Unexpectedly, there was no significant difference in hormonal profiles (FSH, luteinizing hormone [LH], testosterone, and inhibin B levels) and TESE outcomes between unilateral versus bilateral cryptorchidism. This suggests that a history of unilateral cryptorchidism could reflect a bilateral testicular impairment. Interestingly, inhibin B level might be a predictor of successful TESE.

Is Hormonal Treatment of Congenital Undescended Testes Justified? A Debate

Abnormal germ cell development in cryptorchidism is not a result of a congenital dysgenesis but is preceded by a hormone imbalance and perturbation in germ cell-specific gene expression during abrogated mini-puberty. Adequate treatment with low doses of GnRHa enables 86% of men to achieve a normal sperm count and, most importantly, prevent development of azoospermia. GnRHa treatment induces a significant transcriptional response, including protein coding genes involved in pituitary development, the hypothalamic-pituitary-gonadal axis, and testosterone synthesis. Furthermore, hormonal treatment to achieve epididymo-testicular descent as a first choice of treatment of cryptorchidism has a long tradition in Europe. It eliminates the necessity of subsequent surgery. Moreover, in the cases of non-responders it facilitates orchidopexy and contributes considerably to a reduced incidence of unilateral and the more serious bilateral complete post-surgical testicular atrophy.

Role of Ozone Therapy in Preventing Testicular Damage in an Experimental Cryptorchid Rat Model

Background

Cryptorchidism is the most common developmental abnormality of the male reproductive system. If left untreated, it results with infertility and testicular cancer. According to current evidence, surgery is the mainstay of treatment, and hormonal therapy approaches are still under investigation. For the protection of testicular functions, antioxidants have emerged as novel options. This study aimed to evaluate the protective properties of ozone, a strong antioxidant, on testicular tissue.

Material/Methods

Thirty-five male Wistar-albino rats, 1-month-old, were used for the study. Groups were formed as follows: 1) control, 2) sham surgery (cryptorchidism), 3) cryptorchidism plus ozone, 4) cryptorchidism plus human chorionic gonadotropin (hCG), and 5) ozone plus hCG. Surgical procedures were performed on all rats except the control group. All rats except the control group were used to create an experimental cryptorchidism model, and left testes of animals were surgically placed into the abdomen. After 1 month of surgery, groups 3, 4, and 5 were given corresponding treatments intraperitoneally for 4 weeks. At the end of the study period, testicular atrophy index (TAI) and testicular sperm motility (TSM) were assessed and biochemical, histopathological, and immunohistochemical tests were performed.

Results

TAI and TSM were higher in the ozone, hCG, and ozone plus hCG groups than in the sham surgery group (p=0.001). TSM in the ozone group was significantly higher than in the hCG and ozone plus hCG groups. In biochemical analyses, the parameters of oxidative stress (GPx1, MDA, CAT, GSH, SOD) indicated increased oxidative activity in cryptorchidism, which was resolved by applying ozone and hCG (p=0.001). In addition, apoptotic markers, Caspase 3 and bcl-2 were significantly decreased by applying ozone and hCG (p=0.001).

Conclusions

Results of this study suggest that ozone therapy, either as a single agent or in combination with hCG, is a promising approach for protection of testicular functions.

PRDM Histone Methyltransferase mRNA Levels Increase in Response to Curative Hormone Treatment for Cryptorchidism-Dependent Male Infertility

There is a correlation between cryptorchidism and an increased risk of testicular cancer and infertility. During orchidopexy, testicular biopsies are performed to confirm the presence of type A dark (Ad) spermatogonia, which are a marker for low infertility risk (LIR). The Ad spermatogonia are absent in high infertility risk (HIR) patients, who are treated with a gonadotropin-releasing hormone agonist (GnRHa) to significantly lower the risk of infertility. Despite its prevalence, little is known about the molecular events involved in cryptorchidism. Previously, we compared the transcriptomes of LIR versus HIR patients treated with and without hormones. Here, we interpreted data regarding members of the positive regulatory domain-containing (PRDM) family; some of which encoded histone methyltransferases that are important for reproduction. We found there were lower levels of PRDM1, PRDM6, PRDM9, PRDM13, and PRDM14 mRNA in the testes of HIR patients compared with LIR patients, and that PRDM7, PRDM9, PRDM12, and PRDM16 were significantly induced after GnRHa treatment. Furthermore, we observed PRDM9 protein staining in the cytoplasm of germ cells in the testes from LIR and HIR patients, indicating that the mRNA and protein levels corresponded. This result indicated that the curative hormonal therapy for cryptorchidism involved conserved chromatin modification enzymes.

Selecting Infants With Cryptorchidism and High Risk of Infertility for Optional Adjuvant Hormonal Therapy and Cryopreservation of Germ Cells: Experience From a Pilot Study

INTRODUCTION

Orchiopexy for congenital cryptorchid testes is recommended between ½ and 1 year of age to preserve testicular germ cell maturation. Early operation is not enough to preserve fertility in 22 and 36% of cases. Aim of this study was to set up a protocol for optional adjuvant hormonal therapy after orchiopexy and thereafter cryopreservation of testicular biopsies from infants with bilateral cryptorchidism and high infertility risk.

MATERIALS AND METHODS

We included 17 boys with bilateral cryptorchidism, normal FSH, and impaired germ cell number per tubular transverse section (G/T) in testicular biopsies at orchiopexy, 7 months to 3½ years old. Postoperatively, optional adjuvant LHRH (kryptocur^®) 0.2 mg/0.1 mL 2× every second day in 16 weeks were offered. Ten boys were applicable for age matching according to parent's choice of treatment regime and G/T. Five of them had kryptocur^®, and five were controls. Repeat bilateral testicular biopsy evaluation and cryopreservation were offered to all boys 12 months after primary orchiopexy. For cryopreservation, tissue pieces were incubated with a cryoprotectant with a slow program freezing.

RESULTS

Two out of five kryptorcur^®-treated boys normalized both the average G/T and the number of adult dark spermatogonia (Ad-S). Another kryptocur^®-treated boy with initial low G/T and no Ad-S increased the G/T and achieved normal number of Ad-S at time of cryopreservation. In the control group, two patients reached only normal lower range regarding the G/T and the number of Ad-S. None of boys with less than average 0.2 G/T improved significantly, whether they were kryptocur^®-treated or not.

CONCLUSION

Based on literature and the present results, we recommend adjuvant LHRH treatment to boys with cryptorchidism and insufficient genuine gonadotropin stimulation at time of surgery, as these patients have high infertility risk. Cryopreservation should be an option in case of treatment failure of adjuvant LHRH. However, to avoid repeat surgery with biopsy, some parents may choose biopsy for cryopreservation at time of the initial bilateral orchiopexy, well informed that the procedure may only be truly indicated in 22 and 36% of the cases.

On the descent of the epididymo-testicular unit, cryptorchidism, and prevention of infertility

This comprehensive review provides in-depth coverage of progress made in understanding the molecular mechanisms underlying cryptorchidism, a frequent pathology first described in about 1786 by John Hunter. The first part focuses on the physiology, embryology, and histology of epididymo-testicular descent. In the last 20 years epididymo-testicular descent has become the victim of schematic drawings with an unjustified rejection of valid histological data. This part also includes discussion on the roles of gonadotropin-releasing hormone, fibroblast growth factors, Müllerian inhibiting substance, androgens, inhibin B, and insulin-like 3 in epididymo-testicular descent. The second part addresses the etiology and histology of cryptorchidism as well as the importance of mini-puberty for normal fertility development. A critical view is presented on current clinical guidelines that recommend early orchidopexy alone as the best possible treatment. Finally, by combining classical physiological information and the output of cutting-edge genomics data into a complete picture the importance of hormonal treatment in preventing cryptorchidism-induced infertility is underscored.

The influence of hormonal treatment with beta-human chorionic gonadotropin for cryptorchidism on future fertility in rats

INTRODUCTION

There have been two treatment modalities for cryptorchidism such that surgical and hormonal; the latter being highly controversial. While some authors suggest that hormonal treatment increases the number and maturation of germ cells in cryptorchid testes, others believe just the opposite.

OBJECTIVE

We aimed to find out the sperm counts and testicular index; briefly fertility potential of the normally descended contralateral testes in adulthood period in rats treated with Beta-HCG in early period of their lives.

MATERIALS AND METHODS

Three groups, each including 10 rats aged 22 days old, in which delactation and normal feeding can be started, were formed to be Group 1: Sham operated, Group 2: Experimental cryptorchidism (EC) and Group 3: Hormone-treated after experimental cryptorchidism was performed (HT-EC). Left testis was placed in the abdomen in group 2 and 3. In group 1, a sham operation was performed. The rats in EC-HT group received subcutaneous injections of 50 IU/kg Beta-HCG daily for 7 days. Right orchidectomy was performed when they reached reproductive period to evaluate fertility potential with sperm counts and testicular index. Testicular index was calculated according to the formula "testicular length × width/weight of rat". Epididymal sperm count was made with hemocytometer.

DISCUSSION

We evaluated the physical characteristics and fertility potential (sperm counts) of contralateral normal testes during adulthood in rats that underwent experimental unilateral cryptorchidism during infancy. A relationship between testis weight and sperm counts were also investigated. We could not find any direct correlation of sperm count with either testicular weight or testicular index in our study. Although the rats had normal testes at birth, we found decreased sperm counts in contralateral normal testes in EC group. This suggests that unilateral cryptorchidism may cause some systemic effects that reach the other testis. Hormone treatment was not beneficial. This is comparable to Nambirajan et al. who reported histological changes and decreased spermatogenic cell count in contralateral scrotal testes in experimentally induced unilateral cryptorchidism in early period of life in rats. Heiskanen et al. reported that treatment with Beta-HCG leads to decreased total sperm counts in the future due to increased germ cell apoptosis caused by hormonal withdrawal after treatment. Cortes et al. also reported decreased number of germ cells in 1-3 year-old boys who underwent surgery after unsuccessful Beta-HCG treatment. The reasons could be delayed testicular descent or adverse effect of hormone treatment though. Our results concurred with them. Apparently, our model has failed to mimic the pathophysiologic mechanisms of congenital cryptorchidism in humans. Furthermore, we applied hormone treatment in normal rats with normally descended testes. Therefore, the "by-product" information of our study is that, unnecessary use of Beta-HCG during infancy may impair future fertility.

CONCLUSION

Our study suggests that Beta-HCG treatment may decrease sperm counts and decrease the future fertility potential. We could not find any direct correlation of sperm count with either testicular weight or testicular index.

Expression of β-nerve growth factor and homeobox A10 in experimental cryptorchidism treated with exogenous nerve growth factor

With the exception of standard inguinal orchidopexy, treatment of cryptorchidism with human chorionic gonadotropin has been performed for several years; however, its side effects have limited its application. The β‑nerve growth factor (NGF) and homeobox A10 (HoxA10) genes are closely associated with the development of the testes. To the best of our knowledge, whether exogenous NGF alters the endogenous levels of NGF and HoxA10 in cryptorchidism in rats remains to be elucidated. The aim of the present study was to evaluate the gene and protein expression of NGF and HoxA10 in experimental cryptorchidism following treatment with exogenous NGF. A unilateral mechanical cryptorchidism model in Sprague-Dawley rats was established and different concentrations of exogenous NGF were administered to observe the effects of NGF on cryptorchidism. Changes in the gene and protein expression levels of NGF and HoxA10 in the cryptorchid tissues of each group were identified using one step reverse transcription-quantitative polymerase chain reaction, in situ hybridization with digoxigenin‑labeled‑β‑NGF RNA probes, immunofluorescence and immunohistochemistry, respectively. The expression levels of NGF and HoxA10 were markedly higher in the group treated with a high dose of exogenous NGF compared with the group treated with a low dose of exogenous NGF and the group treated with human chorionic gonadotropin. These results confirmed the potential therapeutic effect of exogenous NGF in human cryptorchidism.

Hormonal therapy using gonadotropin releasing hormone for improvement of fertility index among children with cryptorchidism: a meta-analysis and systematic review

BACKGROUND/PURPOSE

Gonadotropin releasing hormone(GnRH) as an adjunct to orchidopexy for the treatment of cryptorchidism is still controversial. Present evidences were studied through a meta-analysis of comparative clinical trials.

METHOD

Systematic literature search was done up to September 30, 2013. Studies were independently appraised by two reviewers. Continuous data of fertility indices were extracted as weighted mean difference (WMD) and standard deviation (SD); while nominal data of fertility indices were extracted as relative risk (RR). Random effects model was used to analyze the pooled effect estimates. Inter-study heterogeneity and publication bias were assessed. PROSPERO Protocol registration (CRD42013004922).

RESULTS

Ten eligible studies were included. The pooled effect estimates showed that cryptorchid children treated with GnRH when compared with controls, have significantly increased germ cell per tubule (WMD: 0.35; 95% CI 0.07-0.62, P=0.01) and increased RR to have normal value of germ cell per tubule (RR: 2.86; 95% CI 1.73-4.71, P<0.0001). Inter-study heterogeneity was noted, source identified with subgroup analysis. Publication bias was not evident. No GnRH related adverse events were reported in all studies.

CONCLUSION

Evidence suggests that a subset of boys with cryptorchidism may benefit from GnRH as adjunctive to orchidopexy in improving the fertility index. However, future studies are recommended to specifically identify subgroup characteristics of cryptorchidism that will clearly benefit from the treatment.

Effects on normalized testicular atrophy index (TAIn) in cryptorchid infants treated with GnRHa pre and post-operative vs surgery alone: a prospective randomized trial and long-term follow-up on 62 cases

PURPOSE

The aim of this study was to investigate the effects of gonadotropin releasing hormone analog (GnRHa) therapy on normalized testicular atrophy index (TAIn) using gonadorelin before and after orchiopexy.

METHODS

62 infants with 87 undescended testes (UDT) were prospectively assigned to two homogeneous groups according to age, position of UDT and TAIn. The patients were randomized to receive either orchiopexy alone or orchiopexy combined with GnRHa as nasal spray at 1.2 mg daily for 4 weeks before surgery and 4 weeks after surgery. Surgical approaches were relative to the position of the UDT: Shoemakers technique in proximal-UDT and Bianchi technique in distal-UDT. All the patients were evaluated clinically and sonographically 1 month before surgery, at the time of surgery, 1 month, 6 months and 5 years after surgery.

RESULTS

Ultrasound data in our study have shown a statistically significant decrease of TAIn in children given additional HT only after 5 years of follow-up, in unilateral cases and in the entirety of treated patients; in bilateral cases this difference was not statistically significant.

CONCLUSION

Patients with a TAIn >20% treated with preoperative and post-operative GnRHa therapy have a significant increase in testicular volume after 5 years of follow-up, as shown by the relative reduction of TAIn values.

Fertility potential in men with a history of congenital undescended testes: a long-term follow-up study

Men with a history of congenital undescended testes (UDT) have an increased risk of fertility problems. Despite no definitive proof, current guidelines recommend early surgical intervention because this may have a positive effect on future fertility potential by preventing degenerative changes of the testes in early life. Also surgical intervention facilitates observability of the testes in view of possible malignancy. We evaluated testicular function in adult men with previous UDT treated at different ages before puberty. A long-term follow-up study of men with previous UDT was performed. Andrological evaluation included medical history taking, physical examination, scrotal ultrasound, determination of reproductive hormones, and semen analysis. Findings were compared with those of a control group of men with normal testicular descent. The influence of age at orchiopexy on future fertility parameters was evaluated in a multivariate regression analysis. 62 men were included of whom seven had had bilateral UDT. Twenty-four patients had had their orchiopexy before the age of 24 months of whom eight men had it before 12 months of age. Forty-eight men had had unsuccessful luteinizing-hormone-releasing-hormone (LHRH) nasal spray treatment during childhood, whereas 14 of 24 men operated before 24 months of age had not received LHRH treatment before orchiopexy. Fertility potential in men with a history of UDT is compromised in comparison with controls. We could not detect any influence of age at orchiopexy on fertility parameters. However, the number of patients operated before the age of 12 months is limited. This study does not support the assumption that early orchiopexy results in better fertility potential.

[Cryptorchidism: from physiopathology to infertility]

Cryptorchidism is a defect of testicular descent. Hormonal, genetic and environmental factors might also contribute to the aetiology of cryptorchidism and its increased incidence in recent years in industrialised countries. Cryptorchidism itself might be considered a complex disease. This testicular pathology represents the best-characterized risk factor for reduced fertility and testicular cancer. The purpose of this review is to better understand physiopathology and mechanisms of infertility in men with history of cryptorchidism.

Cryptorchidism

Cryptorchidism is a very common anomaly of the male genitalia, affecting 2%-4% of male infants and is more common in premature infants. There are two separate stages of testicular descent. The first stage occurs at 8-15 weeks' gestation in the human fetus and is characterized by enlargement of the genito-inguinal ligament, or gubernaculum, and regression of the cranial suspensory ligament. The testis remains close to the future inguinal region as the fetal abdomen grows. Leydig cells in the testis produce insulin-like hormone 3, which stimulates the caudal gubernaculum to grow and become thicker. Mullerian inhibiting substance may have a role in the first phase of descent by stimulating the swelling reaction in the gubernaculum. The second phase of testicular descent requires migration of the gubernaculum and testis from the inguinal region to the scrotum, between 25 and 35 weeks' gestation. The genitofemoral nerve releases calcitonin gene-related peptide, a neurotransmitter that provides a chemotactic gradient to guide migration. The exact cause of cyrptorchidism remains elusive. Information is mainly derived from animal studies (especially in rodents), which may not extrapolate to the human setting. These findings, however, do have some similarities among mammalian species. The current recommended timing for orchidopexy is between 6 and 12 months of life in an effort to preserve the spermatogonia--the stem cells for subsequent spermatogenesis. Despite surgical treatment by orchidopexy, the long-term outcome still remains problematic and controversial. Impaired fertility (33% in unilateral cases and 66% in bilateral undescended testes) and a cancer risk 5-10 times greater than normal is observed over time. Further research into the cause and management of undescended testes is necessary.

Surgical options in disorders of sex development (dsd) with ambiguous genitalia

Disorders of sexual development (DSD) include three main groups of patients: (1) The virilised 46,XX DSD essentially represented by congenital adrenal hyperplasia (CAH) ; (2) The undervirilised 46,XY DSD essentially represented by hypospadias; and (3) the chromosomic jigsaws essentially represented by mixed gonadal dysgenesis. It is in this last group that gender assignment remains a difficult decision involving various indicators, which can be split into four categories: (1) the inside sex (i.e., genes, hormones and target tissues); (2) the outside sex (i.e., anatomy of genitalia including size of the genital tubercle, mullerian cavity and potential adult height of the patient); (3) the functional sex (i.e., potential sexuality and fertility); and (4) and the social sex (i.e., the cultural medium in which the child is brought up). The challenge is to outline the future individual identity of the child in the postnatal period using these indicators. Current evolutions of surgical techniques of 'feminisation' and 'masculinisation' are described as well as their outcomes.