Normal and cryptorchid castration

Surgical exploration of the horse that has presumably had a normal castration or a previously successful cryptorchid surgery remains a distinct challenge. No hard and fast rules dictate a proper course of action for each case. If a horse was anesthetized for routine castration, discovered to have only one scrotal testis, had a brief exploratory on the nondescended side and was recovered, trauma to the inguinal region would probably be sufficiently minimal that an inguinal approach could be used at subsequent exploratory surgery. If the inguinal canal was extensively manipulated and the tail of the epididymis was inadvertently removed, however, one of the alternate approaches would be advisable. Where previous history is unknown, external and rectal palpation, hormonal assays, and careful evaluation of the scrotal/inguinal scars under anesthesia are advisable prior to proceeding with a specific course of action. As previously cited, "one hopes for the best but prepares for the worst." Where inguinal canals are being explored in the supposedly previously castrated horse that still has aggressive male behavior, the surgeon is searching for vaginal process and contents or the stump of the spermatic cord. If the stump is identified to suggest complete previous castration, the stump should contain cremaster muscle, parietal vaginal tunic, testicular vessels, and ductus deferens. If a second nonvascular tubular structure is found but no testicular vessels are found, the tail of the epididymis was inadvertently removed and assumed to be hypoplastic testis. This determination can be difficult to make on gross observation of the stump. Again, a thorough case workup helps one plan in advance for what should be found at surgery.     

Laparoscopic Cryptorchid Castration in Standing Horses

Objective — This article describes a new technique for laparoscopic cryptorchid castration in standing horses. Study Design — Prospective study. Animals or Sample Population — Eight horses aged 11 months to 3 years and weighing between 300 and 643 kg. Methods — Food was withheld for 24 to 36 hours, and then horses were sedated with detomidine HC1 (0.02 to 0.03 mg/kg) and butorphanol tartrate (0.02 mg/kg). The paralumbar fossa region was desensitized with 2% mepivacaine in an inverted “L” pattern and caudal epidural anesthesia was administered with either xylazine (0.18 mg/kg diluted to 10 to 15 mL with 0.9% sodium chloride) or a combination of 2% mepivacaine and xylazine (0.18 mg/kg). Initial laparoscopic exploration was performed from the left flank; in three horses, right flank laparoscopy was needed to complete the procedure. The spermatic cord was ligated within the abdomen with one or two sutures of 0 polydioxanone suture, and the testis or testes removed through a flank incision. Results — In five horses with no palpably descended testes, standing laparoscopy was the only procedure performed, whereas in two horses, the abdominal testis was removed laparoscopically, and the descended testis was removed under short acting anesthesia. In one horse, with nonpalpable testes, it was determined by laparoscopic observation that the testes were in the inguinal canal, and castration was performed under general anesthesia. No surgical or postoperative complications were noted. The right side of the abdomen, and especially the right vaginal ring, could be easily observed from the left side by passing the laparoscope through a small perforation in the mesocolon of the descending colon or by elevating the descending colon with an instrument or by use of an arm in the rectum. Conclusions — The standing laparoscopic approach combined with or without short-acting anesthesia to remove the descended testis is easily performed. Clinical Relevance — This approach will provide surgeons with another option to castrate cryptorchid stallions.     

Cystic Rete Testis in a 3-Year-Old Gypsy Vanner Colt: A Case Report

A 3-year-old Gypsy Vanner colt was presented at the Auburn University College of Veterinary Medicine for castration. The left testicle of the horse was present within the scrotum, but neither the right testicle nor the epididymis was found during external palpation of the right inguinal ring. Removal of the retained testicle by a routine inguinal approach by traction on the gubernaculum and dilation of the internal inguinal ring was not possible. During a parainguinal approach to the abdomen, an enlarged cystic testicle was discovered. Histopathologic diagnosis was cystic rete testis. This case report stresses the importance of preoperative ultrasonographic assessment of cryptorchid testicles to decrease surgical time.     

Inguinal percutaneous ultrasound to locate cryptorchid testes

Standing laparoscopic removal of abdominally retained cryptorchid testes may reduce patient morbidity and speed recovery compared with traditional laparotomy because anaesthesia is avoided and skin incisions are smaller. Reliably locating the testis preoperatively is therefore optimal to avoid unnecessary surgical morbidity and expense. We describe and review the results of a simple method of location using ultrasound scanning of the inguinal region, with a negative result indicating abdominal retention. One hundred and twenty‐seven horses with 141 cryptorchid testes were identified. Eighty‐five testes were identified inguinally: 56 abdominal. Two inguinally retained testes were not observed on ultrasound (false negatives) and 2 testes were considered inguinal but subsequently had to be removed from the abdomen (false positives). Sensitivity of inguinal ultrasound to predict the location of cryptorchid testes was therefore 98% and specificity 97%. The technique described herein proved a reliable technique to locate cryptorchid testes prior to surgery, minimising morbidity and cost. Suspect cryptorchids with no external evidence of testes should undergo a screening blood test prior to this ultrasound method of diagnosis.     

Use of an inguinal approach adapted from equine surgery for cryptorchidectomy in dogs and cats: 26 cases (1999-2010)

OBJECTIVE-To determine whether a surgical technique used in cryptorchid horses can be used successfully to remove testicles retained in the inguinal region or abdominal cavity in dogs and cats. DESIGN-Retrospective case series. ANIMALS-22 dogs and 4 cats with cryptorchidism. PROCEDURES-In 1999 through 2010, 26 cryptorchid patients underwent surgery during which an incision was made over the inguinal ring and the undescended testicle was located for removal via identification of the vaginal process and the embryonic gubernaculum. Castration was performed once a testicle was located in the inguinal region or via removal of an intra-abdominally located testicle through the inguinal canal. RESULTS-4 dogs and 1 cat were bilaterally cryptorchid. Testicles were retained in the abdominal cavity in 18 dogs and in the inguinal region in 4 dogs; in all 4 cats, undescended testicles were located in the inguinal region. Twenty-one dogs and 4 cats were castrated without breaching the abdominal cavity; in one of those dogs, the inguinal ring was enlarged to permit extraction of a tumorous testicle. In 1 dog, the inguinal ring was enlarged into a paramedian laparotomy and viscera were manipulated to exteriorize an intra-abdominally located testicle because the gubernaculum had ruptured. Major intraoperative or long-term complications did not occur. CONCLUSIONS AND CLINICAL RELEVANCE-Results suggested that as in horses, the surgical approach over the inguinal ring, wherein the vaginal process and the remnant of the gubernaculum are identified and used to locate an undescended testicle for removal, can be used successfully in dogs and cats.     

Cryptorchidism and monorchism in cats: 25 cases (1980-1989).

Of 1,345 cats admitted for orchiectomy during a 10-year period, 23 (1.7%) were cryptorchid and 2 (0.1%) were monorchid. Persian cats were over-represented in the cryptorchid population (P = 0.01). Cats were more likely to be unilaterally than bilaterally cryptorchid (P = 0.01). A predisposition for location of undescended testes (abdominal vs inguinal or right vs left side) was not identified in unilateral cryptorchids. All bilateral cryptorchids had abdominally located testes. The most common surgical approaches used for orchiectomy of cryptorchid cats were a caudal ventral midline incision for inguinal testes and a caudal ventral midline celiotomy for abdominal testes.     

Comparison of the diagnosis and management of unilaterally castrated and cryptorchid horses at a referral hospital: 60 cases (2002-2006)

OBJECTIVE: To determine the incidence of unilaterally castrated horses among horses admitted to the hospital for castration and to compare horses that underwent previous unilateral castration with horses that had cryptorchism. DESIGN: Retrospective case series. ANIMALS: 16 unilaterally castrated horses and 44 cryptorchid horses. PROCEDURES: Medical records of horses that were admitted to the veterinary medical teaching hospital for castration, including cryptorchid and unilaterally castrated horses, between January 2002 and December 2006 were reviewed. Medical records of unilaterally castrated horses and cryptorchid horses were examined for age, breed, history, diagnostic procedures, surgical technique of cryptorchidectomy, location of the retained testicle, and cost of surgery. RESULTS: Of 160 horses admitted for castration, 16 (10%) had undergone previous unilateral castration and 44 (27.5%) had cryptorchidism. Unilaterally castrated horses were significantly older than cryptorchid horses. No significant difference was found in left versus right distribution of testicles. No significant difference was found in abdominal versus inguinal distribution of left-sided testicles. Unilaterally castrated horses had a significantly lower proportion of right inguinal testicles, compared with cryptorchid horses. The cost of diagnosis and management of unilaterally castrated horses was significantly greater than in cryptorchid horses. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the distribution of retained testicles is significantly different in unilaterally castrated horses, compared with cryptorchid horses, which may affect the selection of diagnostic and surgical approaches to unilaterally castrated horses.     

一例比格犬先天性隐睾的组织病理学观察

通过研究隐睾症比格(Beagle)犬睾丸、附睾的组织病理学改变,建立适用于GLP的实验动物背景性资料。采用常规组织学方法,对比格犬隐睾及正常侧睾丸、附睾进行光学显微镜观察,确定组织病理学变化特点。与正常组织相比,隐睾胶原纤维组织增生,睾丸曲细精管内仅见少量精原细胞及支持细胞。附睾间质增宽,间质内填充增生的胶原纤维,附睾管内精子缺如。需加强比格犬自发病变的病理监测,为药物安全性评价提供实验动物的背景资料。     

Concentrations of oestradiol and testosterone in peripheral and spermatic venous blood of dogs with unilateral cryptorchidism

Plasma testosterone and oestradiol concentrations were measured in peripheral and spermatic venous blood of 13 dogs with unilateral inguinal cryptorchidism, 9 dogs with unilateral abdominal cryptorchidism, and in a control group of 36 mature normal dogs. The hormone concentrations were similar in the three groups, both in the peripheral and in the spermatic venous blood. The weight of the testes in the control group was correlated with the body weight and there was no significant difference between the weight of the right and the left testes. The weight of the abdominal testes was lower than that of the inguinal testes, and there was no compensatory enlargement of the contralateral scrotal testis. The cryptorchid testes showed little or no histological evidence of spermatogenesis, and spermatogenesis was usually normal in the scrotal testes.     

Testicular Descent in the Dog

The mechanism underlying the process of normal testicular descent in the dog has been examined by a morphological, histological and histochemical analysis of testis and gubernaculum during the period from the 53rd day post coitum (p. c.) until the 40th day post partum (p. p.). Within this period, the testis passes the inguinal canal on the third or fourth day p. p. and reaches its scrotal location on the 35th day p. p. During the entire period the histological composition of the testis (volume percentage of seminiferous tubules, volume percentage of Leydig cells, diameter of seminiferous tubules, number of germ cells) is fairly constant. The △⁵-3β-hydroxysteroid dehydrogenase activity in the Leydig cells before birth suggests a steroid synthesis. Outgrowth and swelling of the gubernaculum occurs until the fifth day p. p. but morphological, histological and histochemical data indicate an onset of gubernacular regression during the last phase of the outgrowth reaction. The migration of the testis from the caudal end of the kidney towards the inguinal canal is associated with the outgrowth of the gubernaculum; during the phase of gubernacular regression, the testis moves from the inguinal canal towards its ultimate location in the scrotal pouch.     

Testicular ischaemic necrosis as a cause of equine cryptorchidism

Cryptorchidism is a fairly common pathology presented to equine surgical facilities with the cryptorchid testicle most commonly located in the abdomen or ipsilateral inguinal canal. The causes of cryptorchidism are not known, but testicular abnormalities have been suggested. Monorchidism as a cause of maldescent of one or both testicles is rare and is hypothesised to be the result of a vascular insult, similar to testicular regression in man. This case report details laparoscopic abdominal exploration of a cryptorchid horse and identification of an abnormal testicular remnant affected by ischaemic necrosis.     

Teratoma in a feline unilateral cryptorchid testis.

A 14- x 12- x 6-cm (approximately 600 g) cryptorchid testis was surgically removed with the omentum from the posterior portion of the abdominal cavity of a 2-year-old male American Shorthair cat. At the time of a previous orchiectomy, a unilateral testis had been discovered in the scrotum. The cut surface of the cryptorchid testis consisted of solid areas with many cysts containing fluid and spongy soft areas. Histologically, the cryptorchid testis was composed of neuroectodermal components and diffuse immature glial tissues, cystic, tubular, and papillary epithelial tissues, and immature cartilaginous tissues. A metastatic mass in the omentum had histologic structures similar to those of the cryptorchid testis. The present case was diagnosed as teratoma in a feline unilateral cryptorchid testis.     

Equine castration: review of anatomy, approaches, techniques and complications in normal, cryptorchid and monorchid horses

Complications associated with equine castration are the most common cause of malpractice claims against equine practitioners in North America. An understanding of the embryological development and surgical anatomy is essential to differentiate abnormal from normal structures and to minimise complications. Castration of the normal horse can be performed using sedation and regional anaesthesia while the horse is standing, or under general anaesthesia when it is recumbent. Castration of cryptorchid horses is best performed under general anaesthesia at a surgical facility. Techniques for castration include open, closed and half-closed techniques. Failure of left and right testicles to descend occurs with nearly equal frequency, however, the left testicle is found in the abdomen in 75% of cryptorchid horses compared to 42% of right testicles. Bilateral cryptorchid and monorchid horses are uncommon. Surgical approaches described for the castration of cryptorchid horses include an inguinal approach with or without retrieval of the scrotal ligament, a parainguinal approach, or less commonly a suprapubic paramedian or flank approach. Laparoscopic castration of cryptorchid horses has recently been described but the technique has limited application in practice at this time. A definitive diagnosis of monorchidism can only be made after surgical exploration of the abdomen, removal of the normal testis and hormonal testing. Hormonal assays reported to be useful include analysis of basal plasma or serum testosterone or oestrone sulphate concentrations, testosterone concentrations following hCG stimulation, and faecal oestrone sulphate concentrations. Reported complications of castration include postoperative swelling, excessive haemorrhage, eventration, funiculitis, peritonitis, hydrocele, penile damage and continued stallion-like behaviour.     

Ultrasonographic detection of chronic epididymitis in a stallion

Clinical signs of chronic epididymitis in a stallion included recurrent signs of inguinal pain--retraction of the right testis into the inguinal area, resentment of palpation of the right testis, and right-sided scrotal swelling. The tail of the right epididymis was firm and seemed to be adhered to the testis. The tail of the left epididymis felt firmer than normal. Ultrasonographically, the diameter of the head of the epididymis was considered larger than normal, was hyperechoic in relation to the right testis, and had an irregular border. Several bright 1- to 5-mm-diameter echogenic areas that alternated with less echogenic areas were seen in the head of the right epididymis. Ultrasonographic findings were interpreted as fibrosis attributable to chronic inflammation. Unilateral castration (right-sided) was performed, but the prognosis was guarded because of presumed involvement of the left epididymis.     

Uncommon castration complication: Penile amputation and sheath ablation following an iatrogenic phallectomy

This report describes the repair of an iatrogenic phallectomy that occurred during an attempted castration of a horse that was discovered to be a unilateral cryptorchid (inguinal testis). Use of a modification of a described phallectomy and sheath ablation technique allowed penile retroversion to be avoided, decreasing excessive dissection and post‐operative morbidity, despite the urethral orifice being positioned more caudally than previously reported.     

Diagnostic ultrasonography for evaluation of cryptorchidism in horses

The location and size of 11 retained testes were accurately determined ultrasonographically. There was 100% correlation between the location of the testis determined by ultrasound vs that determined by surgery. Testicular size determined presurgically in all cases closely approximated the actual size obtained by gross measurement of the excised testis. The cryptorchid testicular echotexture was less dense than that of the normal descended testicles, but was easily identified. Ultrasonographic evaluations were completed by use of an ultrasound base unit with attached 5-MHz transrectal transducer. Rectal scans were started at the pelvic brim and continued in a to-and-fro pattern between the midline and the lateral abdominal wall. When the testis was located, the image was froze to allow measurement. All testicular locations were ascertained ultrasonographically either by rectal or external inguinal scans.     

Function of contralateral testis after artificial unilateral cryptorchidism in dogs

The effects of a cryptorchid testis on the contralateral testis were investigated after artificially producing unilateral cryptorchidism in 8 beagle dogs. Bilateral testicular biopsy and collection of spermatic vein blood and peripheral vein blood were performed at the time of the operation to produce the cryptorchidism and 52 weeks later. The testicular tissue was used for histological examination by light microscopy and measurement of the testicular transferrin (Tf) concentration by enzyme immunoassay. Plasma testosterone (T), estradiol-17 beta (E2), and luteinizing hormone (LH) levels were measured by radioimmunoassay. Semen was collected weekly and its quality was examined. No spermatogenesis was observed in the cryptorchid testes at 52 weeks after the operation, and the number of germ cells in the contralateral testes had decreased but the number of Sertoli cells did not change. The Tf concentration in both testes had also decreased. The mean total number of sperm between 48 and 52 weeks after the operation (194 x 10(6)) was less than half the number before the operation (510 x 10(6)). Mean spermatic vein plasma T levels (51 ng/ml) in the cryptorchid testes 52 weeks after the cryptorchid operation were significantly lower than before the operation (91 ng/ml; P < 0.05). By contrast, spermatic vein plasma E2 levels (80 pg/ml) were significantly higher than the values before the operation (51 pg/ml P < 0.05). The peripheral plasma LH levels decreased. These findings indicate that a large quantity of E2 secreted by the cryptorchid testis inhibits the endocrine and spermatogenic functions of the contralateral testis in the dog. In particular, it is assumed that dysfunction of the contralateral testis is associated with Sertoli cell dysfunction suggested by the low Tf concentration.     

Position and histological structure of the testes in the brown hare (Lepus europaeus) during seasonal regression and recrudescence

The position and histological structure of the testes of 33 brown hares (Lepus europaeus) were studied from July to December. From July to September, the testes were located in the scrotum; in October and November, in some animals, the testes were positioned more or less in the inguinal canal towards the abdominal cavity, and in December none of the investigated animals had testes located in the scrotum. Testes were weighed and a quantitative analysis of tissue components was performed: the diameter of the seminiferous tubules, the depth of the seminiferous epithelium, the thickness of the tunica albuginea, the thickness of the peritubular tissue and the relative proportion of seminiferous tubules were determined. The tunica albuginea and peritubular tissue were thickest in September, October and at the beginning of November. In the same months the testis weight was low, and the diameter of the seminiferous tubules, the depth of the seminiferous epithelium and the relative proportion of seminiferous tubules in the testis tissue were significantly lower than in other months. We did not find any correlation between testicular regression or testis weight reduction and the change in the position of the testes. During recrudescence of spermatogenesis in November and December the testes were located in the inguinal canal.     

Noninvasive Inguinal Approach for Cryptorchidectomy in Thirty-eight Stallions

We describe the results of the noninvasive inguinal approach in 38 cases of cryptorchidism. Whether the retained testis was intra-abdominal or in the inguinal canal, this technique was found to be an easy, reliable method of locating abdominal and inguinal testes through a normal body opening. No postoperative complications were recorded in this series of cases and the postoperative rest period was minimal.     

Testicular superoxide dismutase activity, heat shock protein 70 concentration and blood plasma inhibin-alpha concentration of dogs with a Sertoli cell tumor in a unilateral cryptorchid testis

The proportions of Sertoli cell tumor (SCT), seminoma and Leydig cell tumor in 50 dogs with unilateral testicular tumors were 52%, 36% and 12%, respectively. The rate of occurrence of SCT in the cryptorchid testis was very high (71%). The testicular superoxide dismutase (SOD) activity, testicular heat shock protein (HSP) 70 concentration and peripheral blood plasma inhibin (INH)-alpha concentration of 10 dogs with a unilateral cryptorchid testis and no testicular tumors, 10 dogs with SCT in a unilateral cryptorchid testis and 10 normal dogs, all aged 5-15 years, were measured in order to identify high risk factors for the occurrence of SCT in the canine cryptorchid testis. The mean SOD activity in cryptorchid testes and SCTs was significantly lower and higher, respectively, than in normal testes (both P<0.01). The mean HSP 70 concentration in both cryptorchid testes and SCTs was significantly higher than in normal testes (both P<0.01). The mean plasma INH-alpha concentration of the cryptorchid and SCT dogs was significantly lower and higher, respectively, than in normal dogs (P<0.05 and 0.01, respectively). The low SOD activity in the cryptorchid testis, low blood plasma INH-alpha concentration of the cryptorchid dogs and high HSP 70 concentration in the SCTs may be related to the occurrence of SCT and tumor cell proliferation in canine cryptorchid testes.