The Undescended Testis
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《美国医学杂志》
Sheffield Children's Hospital, Western Bank, Sheffield S10 2TH, UK, United Kingdom
Abstract
Abstract. Testicular development is determined by the influence of the SRY gene on the Y chromosome of the fetus. This influences the germ cells to produce testosterone and Mullerian inhibiting substance which control descent of the testis. Maldescent of the testis occurs in 0.8% of boys. Current best advice is to perform orchidopexy before the age of two years, therefore a programme for examination by skilled healthcare workers should be established in the first year of life. Indications for surgery include a possible beneficial effect on fertility, malignant potential particularly if intra-abdominal, torsion or trauma and social considerations. Hormonal treatment in the first three months of life is recommended by some. Laparoscopy is the optimum method for evaluating and managing the intra-abdominal testis. [Indian J Pediatr 2005; 72 (5) : -432]
Keywords: Undescended testis; Embryology; Management
Male gender is determined by the genotype 46 XY. The primitive germ cells migrate from the yolk sac to the developing embryo in the fifth week of development and differentiate into testicular elements under the influence of the SRY gene (testis determining gene factor) on the Y chromosome. [1,2] Medial to the primitive mesonephros mesodermal cells and overlying columnar epithelium condense to form the genital ridge with the epithelial cells which migrate into the mesenchyme to form sex cords. These develop into the seminiferous tubules, and Leydig cells develop from mesoderm and secrete testosterone by the ninth week of development. At the same time Müllerian inhibiting substance (MIS) is produced and this inhibits development of the internal female organs and initiates the descent of the testis as far as the inguinal region.[3] Testosterone is necessary for the positive step of the development of male external genital organs including the penis and scrotum and for conversion of the Wolffian duct into epididymis, vas and seminal vesicles. In addition by conversion into dihydro-testosterone it is the humoral factor driving the second part of testicular descent into the scrotum. This humoral function in turn is under the control of the central pituitary gonadotrophins, failure of which will lead to cryptorchidism as will deficiency of MIS, testosterone or 5a reductase, necessary for conversion of testosterone into the more active dihydro-testosterone.
The mode by which MIS and testosterone influence testicular descent is still unclear. However, there may also be mechanical factors involved. Arguments in support of this relate to the higher incidence of cryptorchidism in cases of congenital defects of the abdominal wall such as prune belly syndrome, gastroschisis and high lesions of spina bifida. The latter though may relate to studies indicating that testosterone may act indirectly via the spinal nucleus of the genito-femoral nerve.[4] Most authors believe that the gubernaculum is in some way related to this process in view of morphological changes during antenatal development, an hypothesis first proposed by William Hunter.[5]
Postnatal Testicular Development
0It is important to understand this aspect of cryptorchidism to make a rational decision regarding timing of examination of male infants. For many years it was regarded as essential to have the testes placed in the scrotum by the onset of puberty. Progressively, with little scientific evidence, the age recommended for surgery reduced to around 5 years of age. Even now there is no firm proof that early surgery has an improved outcome for testicular function so for inexperienced surgeons it could be argued that surgery should be delayed to 5 years for fear of damage to the delicate structures of the vas. However, is it ethical to allow an inexperienced surgeon to operate on children when outcome of surgery appears to be better in the younger child.[6]
In the UK at birth around 2.7% of term boys have an undescended testis, but the figure is 21% for those with birth weight less than 2500 gm. but by 1 year of age this figure has fallen to 0.8%.[7] This justifies a period of observation of a testis that is not within the scrotum at birth, particularly in pre-term infants in whom the natural descent in weeks 30-40 of gestational age may be observed after delivery. Postnatal descent may be due to a significant rise in serum testosterone that reduces by 3-4 months after birth. Rarely does a testis descend after 3 months of age but general advice is to wait until the first birthday. Recent evidence in western countries has indicated an increase in the incidence of cryptorchidism[8 ]although at present it is not clear if this is only a transient observation. It has been postulated that this increase may be related to environmental changes.[9] Whether any of these mechanisms have any relevance to the condition of late ascent of the testis is unknown. There is little doubt that such an event may happen,[10] though very careful observation is needed to distinguish this from a stubborn retractile testis and patient observation into puberty may avoid an operation.
Several studies have been performed to evaluate the ultra-structure of the undescended testis after birth. From the age of 2 years, changes occur in the testis which can be found both on light microscopy and electron microscopy[11] with a qualitative difference in the changes the higher the testis lies. The influence of orchidopexy on these changes is difficult to assess. In the presence of a normal contra-lateral testis hormonal function and spermatogenesis in the individual will be normal. With the present knowledge of testicular changes associated with cryptorchidism it is unethical to undertake a controlled study of early versus late surgery for a group of children with a solitary but undescended testis. Where both testes are undescended, although an internal control would be present, it would also be unethical to operate early on one testis leaving the other to be operated upon at a later date.
Clinical examination
The structure of medical systems varies throughout the world. For a given medical system there must be guidelines for screening for undescended testes in view of the relatively high frequency. In view of the natural history of descent the ideal is to examine all boys at birth for testicular position. However, at times the scrotal contents, presumably the thick gubernaculum, can be difficult to distinguish from a testis. For this reason it is wise to repeat the examination at a routine baby check at 6 weeks of age. If a testis is found missing then the child should be seen at one year of age. This is an important examination so needs to be performed by a professional trained and experienced in such examination. Who this will be, depends on the structure of the medical services available and could be a specially trained nurse or a doctor. Either way the team needs to be led by a pediatric surgeon.
The boy must be comfortable, lying flat in a non-threatening environment. Each groin in turn is stroked with the flat of the index finger of the examiner from above the mid inguinal point towards the scrotum where the testis should be transferred to the fingers of the opposite hand. To be certain a testis is normally descended the organ must reach and stay at the lower pole of the scrotum. Evidence from the family or, if old enough, the patient is often illuminating if testicular descent has been noticed earlier on.
The major differential diagnosis is that of a retractile testis. In the first year of life the cremaster, derived from the internal oblique muscle, is not strong so in the hands of an experienced observer there should seldom be a difficulty in establishing the correct diagnosis. After two years of age it becomes progressively more difficult to be certain of the true status of the testis in some boys. The boy may be asked to squat or sit crossed legged on the couch and then the examiner leans gently over his shoulder. A retractile testis may be coaxed into the scrotum and reach the lower pole. If it does not then the child should be re-examined to confirm the findings if there is any doubt based on clinical history or examination. If there is a history that the testis was seen in the scrotum earlier in life then the differential diagnosis lies between a retractile and an ascended testis. Management of these children is difficult and may need to take into account the emotional pressures exerted upon or within the family. If a family accept a wait and see policy then the boy may be re-evaluated as he progresses through puberty as a retractile testis will descend as development progresses. Spontaneous descent if at all possible is far more advantageous than surgical intervention.
Indications for Intervention
0No matter where a testis lies after puberty, in response to HCG stimulation it will secrete testosterone. This in itself is advantageous in searching for evidence of testicular tissue in the absence of either testis being palpable. However, if there is one palpable testis then no information is gained about the presence of the opposite testis. Management plans for an undescended testis therefore depends on other factors.
Fertility
The correlation between fertility with unilateral cryptorchid subjects and normal individuals has been recognised for some time.[12] The same paper demonstrated the impaired fertility in males who had undergone bilateral surgery having only a 44% paternity rate. This paper related to surgery performed mostly in children over the age of 2 years and some 40 years ago or more but the results have been confirmed in recent studies.[13] Fertility has been directly related to the age at orchidopexy[14] with a rate of 87.5% claimed if surgery is performed before 2 years of age falling to 14% if operated at 13 years or more but such figures may be influenced by the distribution of unilateral and bilateral cases. Such infertility may relate to levels of follicle stimulating hormone[13] which correlates with the finding of failure of normal maturation of germ cells in cryptorchid testes.[15]
Malignant Potential
That there is an association between cryptorchidism and testicular malignancy is not in dispute, the risk being greater the higher the testis lies particularly when intra-abdominal. However, to quantify the risk is difficult with figures of a 10 to 30 fold increase over the incidence in normal individuals. It appears in some reports that the later surgery is undertaken the greater is the risk[16] though this is not confirmed by all authors and evidence suggests that testicular biopsy may lead to the later development of malignancy.[17] On the basis of detecting carcinoma in situ prepubertal biopsies are not predictive of later malignancy.[18]
Trauma
It is stated that a testis lying in front of the pubic bone is more at risk of trauma. This would seem eminently logical though very rare in current times when orchidopexy is routinely performed.
Torsion
There is an increased risk of testicular torsion when the testis is not normally placed in the scrotum. This probably relates to the abnormal anatomical development of the related structures leading to poor apposition of epididymis and testis similar to that found in torsion of a normally descended testis. However, it is more likely that any individual clinician will see torsion affecting a normally descended testis than an undescended testis. Torsion of an appendage of the testis may afflict either the undescended testis or the testis following orchidopexy unless care has been taken to excise such appendages at the initial operation.
Psycho-social issues
Emotional factors are unlikely to affect the prepubertal boy as many of their peers will have retractile testes. However, after that age anatomical deviation from the normal may lead to self-consciousness. Furthermore, it is not possible to enter military service with an undescended testis.
Treatment options
Hormone Therapy
Exogenous or endogenous gonadotrophins will cause a retractile testis to descend. This makes scientific evaluation of trials of hormone therapy for cryptorchidism difficult as there is no strictly objective test for retractile testes. Furthermore, most advocates of hormone therapy claim it to be most effective in the first three months of life, a time when there is maximal rise in testosterone levels in infants. Preliminary studies of stimulating gonadotrophin release in the first months of life of boys with cryptorchidism[15] indicate that in future years such therapy may prove to be beneficial. However, the fact that the greatest effect in terms of testicular maturation seems to be on the contra-lateral descended testis leads to some doubt that improved fertility will be achieved.
Surgery
The time-honoured management of the undescended testis is surgical mobilisation and placement into the scrotum (Fig 1). Consistently good results can be expected from careful mobilisation of the cord and testis with retention of the testis within a scrotal or sub-dartos pouch.[19] Postoperatively significant complications are uncommon. However, there is a small incidence of testicular atrophy, which is detectable at 6 months after the operation.[6] In a few instances, the testis may retract into the groin. In this case it is debatable as to whether early re-exploration is the best choice or waiting for pubertal changes as anecdotal experience indicates that late improvement of the position may occur and re-exploration certainly carries risk of damage to the cord structures.
Management of the Impalpable Testis
0When neither testis is palpable on clinical examination HCG stimulation test will determine whether there is any functioning testicular tissue. This is of no help where there is one palpable testis. The high risk of malignant change in an intra-abdominal testis makes thorough exploration mandatory. Imaging using MR or CT scanning or ultra-sound examination can lead to the identification of an intra-abdominal testis. However, non-visualisation does not exclude the possibility of an intra-abdominal testis. Laparoscopy has for some time been regarded as the definitive procedure.[20] For appropriate cases, laparoscopic orchidopexy can be performed.[21] If the testis is very high and there is a normally descended contra-lateral testis then orchidectomy is appropriate since function is of no concern but the malignant potential, in spite of orchidopexy, is unchanged. If the testis is relatively low and can be drawn to the opposite deep ring within the abdomen then laparoscopic orchidopexy is appropriate. When the testis is intermediate in position then a decision has to be made as to whether or not to perform a two stage Fowler Stevens procedure. This comprises division of the gonadal vessels distant from the testis and then 6 to 8 weeks later after establishment of collateral blood supply from the vas and gubernaculum the testis is mobilised and placed in the scrotum. Prior to such complex surgery parents of the child should be counselled both on basic principles and to avoid later litigation
References
1. Gubbay J, Collingon J, Koopman P et al. A gene mapping to the sex-chromosome region of the mouse Y chromosome is a member of a novel family of embryonically expressed genes. Nature 1990; 346: 245-250.
2. Sinclair AH, Berta P, Palmer M et al. A gene from the human sex-determining region encodes a protein with homology to a conserved DNA-binding motif. Nature 1990; 46 : 240-244.
3. Hutson JM, Donahoe PK. The hormonal control of testicular descent. Endocr Rev 1986; 7 : 270-283.
4. Larkin SL, Hutson SM, Williams PMI. Localisation of the CGRP immunoreactivity in the nucleus of the genitofemoral nerve. Paediatr Surg Int 1991; 6 : 176-179.
5. Hunter W. Observations on the State of the Testis in the Foetus and on the Hernia Congenita: Medical Commentaries. London: A. Hamilton.
6. Wilson-Storey D, McGenity K, Dickson JA. Orchidopexy: the younger the better J R Coll Surg Ed 1990; 35 : 362-364.
7. Scorer CG. The descent of the testis. Arch Dis Child 1964; 39 : 605-609.
8. John Radcliffe Hospital Cryptorchidism Study Group. Cryptorchidism: an apparent substantial increase since 1960. Brit Med J 1986; 293 : 1400-1405.
9. Skakkebaek NE, Rajpert De MeytsE, Main KM. Testicular dysgenesis syndrome: An increasingly common developmental disorder with environmental aspects. Hum-Reprod 2001; 6 : 972-978.
10. Atwell J. Ascent of the testis: Fact or fiction Br J Urol 1985;57 : 474-477.
11. Mengel W, Heinz HA, Sippe WG, Heckel WC. Studies on cryptorchidism: A comparison of histological findings in the germinative epithelium before and after the 2nd year of life. J Pediatr Surg 1974; 9 : 224-450.
12. Atkinson PM. A follow-up study of surgically treated cryptorchid patients. J Pediatr Surg 1975; 10 : 115-119.
13. Cortes D, Thorup J, Lindenberg S, Visfeldt J. Infertility despite surgery for cryptorchidism in childhood can be classified by patients with normal or elevated follicle-stimulating hormone and identified at orchidopexy. Br J Urol Int 2003; 91 : 670-674.
14. Ludwig G, Potempa H. Der Optimale Zeitpunkt der Behandlung des Kriptorchidismus. Dtsch Med Wochenschr 1995; 100 : 680.
15. Huff DS, Fenig DM, Canning DA, Carr MG, Zderic SA, Snyder HM 3rd. Abnormal germ cell development in cryptorchidism. Horm-Res 2001; 55 : 11-17.
16. Martin DC. Germinal cell tumours of the testis after orchidopexy. J Urol 1997; 121 : 433-435.
17. Swerdlow AJ, Higgins CD, Pike MC. Risk of testicular cancer in cohort of boys with cryptorchidism. Br Med J 1997; 314 : 1507-1511.
18. Parkinson MC, Swerdlow AJ, Pike MC. Carcinoma in situ in boys with cryptorchidism: when can it be detected Br J Urol 1994; 73 : 431-435.
19. Brown S, MacKinnon AE. The scrotal pouch operation for undescended testis. Ann R Coll Surg Engl 1979; 61 : 377-380.
20. Godbole PP, Morecroft JA, MacKinnon AE. Laparoscopy for the impalpable testis. Br J Surg 1997; 84 : 1430-1432.
21. Topuzlu Tekant G, Emir H, Eroglu E, Akman M, Büyükünal C, Danismend N et al. Experience with laparoscopy in nonpalpable testis. Eur J Pediatr Surg 2001; 11 : 177-181(MacKinnon AE)
Abstract
Abstract. Testicular development is determined by the influence of the SRY gene on the Y chromosome of the fetus. This influences the germ cells to produce testosterone and Mullerian inhibiting substance which control descent of the testis. Maldescent of the testis occurs in 0.8% of boys. Current best advice is to perform orchidopexy before the age of two years, therefore a programme for examination by skilled healthcare workers should be established in the first year of life. Indications for surgery include a possible beneficial effect on fertility, malignant potential particularly if intra-abdominal, torsion or trauma and social considerations. Hormonal treatment in the first three months of life is recommended by some. Laparoscopy is the optimum method for evaluating and managing the intra-abdominal testis. [Indian J Pediatr 2005; 72 (5) : -432]
Keywords: Undescended testis; Embryology; Management
Male gender is determined by the genotype 46 XY. The primitive germ cells migrate from the yolk sac to the developing embryo in the fifth week of development and differentiate into testicular elements under the influence of the SRY gene (testis determining gene factor) on the Y chromosome. [1,2] Medial to the primitive mesonephros mesodermal cells and overlying columnar epithelium condense to form the genital ridge with the epithelial cells which migrate into the mesenchyme to form sex cords. These develop into the seminiferous tubules, and Leydig cells develop from mesoderm and secrete testosterone by the ninth week of development. At the same time Müllerian inhibiting substance (MIS) is produced and this inhibits development of the internal female organs and initiates the descent of the testis as far as the inguinal region.[3] Testosterone is necessary for the positive step of the development of male external genital organs including the penis and scrotum and for conversion of the Wolffian duct into epididymis, vas and seminal vesicles. In addition by conversion into dihydro-testosterone it is the humoral factor driving the second part of testicular descent into the scrotum. This humoral function in turn is under the control of the central pituitary gonadotrophins, failure of which will lead to cryptorchidism as will deficiency of MIS, testosterone or 5a reductase, necessary for conversion of testosterone into the more active dihydro-testosterone.
The mode by which MIS and testosterone influence testicular descent is still unclear. However, there may also be mechanical factors involved. Arguments in support of this relate to the higher incidence of cryptorchidism in cases of congenital defects of the abdominal wall such as prune belly syndrome, gastroschisis and high lesions of spina bifida. The latter though may relate to studies indicating that testosterone may act indirectly via the spinal nucleus of the genito-femoral nerve.[4] Most authors believe that the gubernaculum is in some way related to this process in view of morphological changes during antenatal development, an hypothesis first proposed by William Hunter.[5]
Postnatal Testicular Development
0It is important to understand this aspect of cryptorchidism to make a rational decision regarding timing of examination of male infants. For many years it was regarded as essential to have the testes placed in the scrotum by the onset of puberty. Progressively, with little scientific evidence, the age recommended for surgery reduced to around 5 years of age. Even now there is no firm proof that early surgery has an improved outcome for testicular function so for inexperienced surgeons it could be argued that surgery should be delayed to 5 years for fear of damage to the delicate structures of the vas. However, is it ethical to allow an inexperienced surgeon to operate on children when outcome of surgery appears to be better in the younger child.[6]
In the UK at birth around 2.7% of term boys have an undescended testis, but the figure is 21% for those with birth weight less than 2500 gm. but by 1 year of age this figure has fallen to 0.8%.[7] This justifies a period of observation of a testis that is not within the scrotum at birth, particularly in pre-term infants in whom the natural descent in weeks 30-40 of gestational age may be observed after delivery. Postnatal descent may be due to a significant rise in serum testosterone that reduces by 3-4 months after birth. Rarely does a testis descend after 3 months of age but general advice is to wait until the first birthday. Recent evidence in western countries has indicated an increase in the incidence of cryptorchidism[8 ]although at present it is not clear if this is only a transient observation. It has been postulated that this increase may be related to environmental changes.[9] Whether any of these mechanisms have any relevance to the condition of late ascent of the testis is unknown. There is little doubt that such an event may happen,[10] though very careful observation is needed to distinguish this from a stubborn retractile testis and patient observation into puberty may avoid an operation.
Several studies have been performed to evaluate the ultra-structure of the undescended testis after birth. From the age of 2 years, changes occur in the testis which can be found both on light microscopy and electron microscopy[11] with a qualitative difference in the changes the higher the testis lies. The influence of orchidopexy on these changes is difficult to assess. In the presence of a normal contra-lateral testis hormonal function and spermatogenesis in the individual will be normal. With the present knowledge of testicular changes associated with cryptorchidism it is unethical to undertake a controlled study of early versus late surgery for a group of children with a solitary but undescended testis. Where both testes are undescended, although an internal control would be present, it would also be unethical to operate early on one testis leaving the other to be operated upon at a later date.
Clinical examination
The structure of medical systems varies throughout the world. For a given medical system there must be guidelines for screening for undescended testes in view of the relatively high frequency. In view of the natural history of descent the ideal is to examine all boys at birth for testicular position. However, at times the scrotal contents, presumably the thick gubernaculum, can be difficult to distinguish from a testis. For this reason it is wise to repeat the examination at a routine baby check at 6 weeks of age. If a testis is found missing then the child should be seen at one year of age. This is an important examination so needs to be performed by a professional trained and experienced in such examination. Who this will be, depends on the structure of the medical services available and could be a specially trained nurse or a doctor. Either way the team needs to be led by a pediatric surgeon.
The boy must be comfortable, lying flat in a non-threatening environment. Each groin in turn is stroked with the flat of the index finger of the examiner from above the mid inguinal point towards the scrotum where the testis should be transferred to the fingers of the opposite hand. To be certain a testis is normally descended the organ must reach and stay at the lower pole of the scrotum. Evidence from the family or, if old enough, the patient is often illuminating if testicular descent has been noticed earlier on.
The major differential diagnosis is that of a retractile testis. In the first year of life the cremaster, derived from the internal oblique muscle, is not strong so in the hands of an experienced observer there should seldom be a difficulty in establishing the correct diagnosis. After two years of age it becomes progressively more difficult to be certain of the true status of the testis in some boys. The boy may be asked to squat or sit crossed legged on the couch and then the examiner leans gently over his shoulder. A retractile testis may be coaxed into the scrotum and reach the lower pole. If it does not then the child should be re-examined to confirm the findings if there is any doubt based on clinical history or examination. If there is a history that the testis was seen in the scrotum earlier in life then the differential diagnosis lies between a retractile and an ascended testis. Management of these children is difficult and may need to take into account the emotional pressures exerted upon or within the family. If a family accept a wait and see policy then the boy may be re-evaluated as he progresses through puberty as a retractile testis will descend as development progresses. Spontaneous descent if at all possible is far more advantageous than surgical intervention.
Indications for Intervention
0No matter where a testis lies after puberty, in response to HCG stimulation it will secrete testosterone. This in itself is advantageous in searching for evidence of testicular tissue in the absence of either testis being palpable. However, if there is one palpable testis then no information is gained about the presence of the opposite testis. Management plans for an undescended testis therefore depends on other factors.
Fertility
The correlation between fertility with unilateral cryptorchid subjects and normal individuals has been recognised for some time.[12] The same paper demonstrated the impaired fertility in males who had undergone bilateral surgery having only a 44% paternity rate. This paper related to surgery performed mostly in children over the age of 2 years and some 40 years ago or more but the results have been confirmed in recent studies.[13] Fertility has been directly related to the age at orchidopexy[14] with a rate of 87.5% claimed if surgery is performed before 2 years of age falling to 14% if operated at 13 years or more but such figures may be influenced by the distribution of unilateral and bilateral cases. Such infertility may relate to levels of follicle stimulating hormone[13] which correlates with the finding of failure of normal maturation of germ cells in cryptorchid testes.[15]
Malignant Potential
That there is an association between cryptorchidism and testicular malignancy is not in dispute, the risk being greater the higher the testis lies particularly when intra-abdominal. However, to quantify the risk is difficult with figures of a 10 to 30 fold increase over the incidence in normal individuals. It appears in some reports that the later surgery is undertaken the greater is the risk[16] though this is not confirmed by all authors and evidence suggests that testicular biopsy may lead to the later development of malignancy.[17] On the basis of detecting carcinoma in situ prepubertal biopsies are not predictive of later malignancy.[18]
Trauma
It is stated that a testis lying in front of the pubic bone is more at risk of trauma. This would seem eminently logical though very rare in current times when orchidopexy is routinely performed.
Torsion
There is an increased risk of testicular torsion when the testis is not normally placed in the scrotum. This probably relates to the abnormal anatomical development of the related structures leading to poor apposition of epididymis and testis similar to that found in torsion of a normally descended testis. However, it is more likely that any individual clinician will see torsion affecting a normally descended testis than an undescended testis. Torsion of an appendage of the testis may afflict either the undescended testis or the testis following orchidopexy unless care has been taken to excise such appendages at the initial operation.
Psycho-social issues
Emotional factors are unlikely to affect the prepubertal boy as many of their peers will have retractile testes. However, after that age anatomical deviation from the normal may lead to self-consciousness. Furthermore, it is not possible to enter military service with an undescended testis.
Treatment options
Hormone Therapy
Exogenous or endogenous gonadotrophins will cause a retractile testis to descend. This makes scientific evaluation of trials of hormone therapy for cryptorchidism difficult as there is no strictly objective test for retractile testes. Furthermore, most advocates of hormone therapy claim it to be most effective in the first three months of life, a time when there is maximal rise in testosterone levels in infants. Preliminary studies of stimulating gonadotrophin release in the first months of life of boys with cryptorchidism[15] indicate that in future years such therapy may prove to be beneficial. However, the fact that the greatest effect in terms of testicular maturation seems to be on the contra-lateral descended testis leads to some doubt that improved fertility will be achieved.
Surgery
The time-honoured management of the undescended testis is surgical mobilisation and placement into the scrotum (Fig 1). Consistently good results can be expected from careful mobilisation of the cord and testis with retention of the testis within a scrotal or sub-dartos pouch.[19] Postoperatively significant complications are uncommon. However, there is a small incidence of testicular atrophy, which is detectable at 6 months after the operation.[6] In a few instances, the testis may retract into the groin. In this case it is debatable as to whether early re-exploration is the best choice or waiting for pubertal changes as anecdotal experience indicates that late improvement of the position may occur and re-exploration certainly carries risk of damage to the cord structures.
Management of the Impalpable Testis
0When neither testis is palpable on clinical examination HCG stimulation test will determine whether there is any functioning testicular tissue. This is of no help where there is one palpable testis. The high risk of malignant change in an intra-abdominal testis makes thorough exploration mandatory. Imaging using MR or CT scanning or ultra-sound examination can lead to the identification of an intra-abdominal testis. However, non-visualisation does not exclude the possibility of an intra-abdominal testis. Laparoscopy has for some time been regarded as the definitive procedure.[20] For appropriate cases, laparoscopic orchidopexy can be performed.[21] If the testis is very high and there is a normally descended contra-lateral testis then orchidectomy is appropriate since function is of no concern but the malignant potential, in spite of orchidopexy, is unchanged. If the testis is relatively low and can be drawn to the opposite deep ring within the abdomen then laparoscopic orchidopexy is appropriate. When the testis is intermediate in position then a decision has to be made as to whether or not to perform a two stage Fowler Stevens procedure. This comprises division of the gonadal vessels distant from the testis and then 6 to 8 weeks later after establishment of collateral blood supply from the vas and gubernaculum the testis is mobilised and placed in the scrotum. Prior to such complex surgery parents of the child should be counselled both on basic principles and to avoid later litigation
References
1. Gubbay J, Collingon J, Koopman P et al. A gene mapping to the sex-chromosome region of the mouse Y chromosome is a member of a novel family of embryonically expressed genes. Nature 1990; 346: 245-250.
2. Sinclair AH, Berta P, Palmer M et al. A gene from the human sex-determining region encodes a protein with homology to a conserved DNA-binding motif. Nature 1990; 46 : 240-244.
3. Hutson JM, Donahoe PK. The hormonal control of testicular descent. Endocr Rev 1986; 7 : 270-283.
4. Larkin SL, Hutson SM, Williams PMI. Localisation of the CGRP immunoreactivity in the nucleus of the genitofemoral nerve. Paediatr Surg Int 1991; 6 : 176-179.
5. Hunter W. Observations on the State of the Testis in the Foetus and on the Hernia Congenita: Medical Commentaries. London: A. Hamilton.
6. Wilson-Storey D, McGenity K, Dickson JA. Orchidopexy: the younger the better J R Coll Surg Ed 1990; 35 : 362-364.
7. Scorer CG. The descent of the testis. Arch Dis Child 1964; 39 : 605-609.
8. John Radcliffe Hospital Cryptorchidism Study Group. Cryptorchidism: an apparent substantial increase since 1960. Brit Med J 1986; 293 : 1400-1405.
9. Skakkebaek NE, Rajpert De MeytsE, Main KM. Testicular dysgenesis syndrome: An increasingly common developmental disorder with environmental aspects. Hum-Reprod 2001; 6 : 972-978.
10. Atwell J. Ascent of the testis: Fact or fiction Br J Urol 1985;57 : 474-477.
11. Mengel W, Heinz HA, Sippe WG, Heckel WC. Studies on cryptorchidism: A comparison of histological findings in the germinative epithelium before and after the 2nd year of life. J Pediatr Surg 1974; 9 : 224-450.
12. Atkinson PM. A follow-up study of surgically treated cryptorchid patients. J Pediatr Surg 1975; 10 : 115-119.
13. Cortes D, Thorup J, Lindenberg S, Visfeldt J. Infertility despite surgery for cryptorchidism in childhood can be classified by patients with normal or elevated follicle-stimulating hormone and identified at orchidopexy. Br J Urol Int 2003; 91 : 670-674.
14. Ludwig G, Potempa H. Der Optimale Zeitpunkt der Behandlung des Kriptorchidismus. Dtsch Med Wochenschr 1995; 100 : 680.
15. Huff DS, Fenig DM, Canning DA, Carr MG, Zderic SA, Snyder HM 3rd. Abnormal germ cell development in cryptorchidism. Horm-Res 2001; 55 : 11-17.
16. Martin DC. Germinal cell tumours of the testis after orchidopexy. J Urol 1997; 121 : 433-435.
17. Swerdlow AJ, Higgins CD, Pike MC. Risk of testicular cancer in cohort of boys with cryptorchidism. Br Med J 1997; 314 : 1507-1511.
18. Parkinson MC, Swerdlow AJ, Pike MC. Carcinoma in situ in boys with cryptorchidism: when can it be detected Br J Urol 1994; 73 : 431-435.
19. Brown S, MacKinnon AE. The scrotal pouch operation for undescended testis. Ann R Coll Surg Engl 1979; 61 : 377-380.
20. Godbole PP, Morecroft JA, MacKinnon AE. Laparoscopy for the impalpable testis. Br J Surg 1997; 84 : 1430-1432.
21. Topuzlu Tekant G, Emir H, Eroglu E, Akman M, Büyükünal C, Danismend N et al. Experience with laparoscopy in nonpalpable testis. Eur J Pediatr Surg 2001; 11 : 177-181(MacKinnon AE)