Testicles

Introduction

Prepubertal castration of puppies and kittens (as early as six weeks of age) is slowly increasing in popularity in the United States, particularly in the shelter setting, as a result of mounting evidence of the safety of the procedure, on both a short and long-term basis. Puppies and kittens undergoing prepubertal castration have shorter recovery rates, lower morbidity, and similar mortality rates as compared to those neutered at a more traditional age (≥ six months of age). Although many safety concerns, including urethral obstruction in male cats, have been raised regarding early age castration, long-term outcome in cats and dogs undergoing early neutering is similar to those undergoing traditional age neutering. Early age castration in dogs and cats is a safe procedure when appropriate anesthetic and surgical principles and techniques are applied.

Surgical Procedures and Techniques

The surgical anatomy of the pediatric puppy or kitten reproductive tract is identical to that of the adult dog or cat; however, pediatric testes are extremely small, highly mobile, and the spermatic cords are susceptible to tearing if not handled gently.

Anesthetic and surgical considerations for the pediatric patient, differ somewhat from the adult patient, and include increased risk of hypoglycemia and hypothermia, a relatively small blood volume, and delicate tissues. Prolonged fasting may result in hypoglycemia because hepatic glycogen stores are minimal in neonates. Thus, food should be withheld no longer than 8 hours, with 3 to 4 hours recommended for the youngest patients (6 to 8 weeks).^1,2 Minimizing operative times and the use of warm water blankets can decrease hypothermia. The use of warmed scrub solution (chlorhexidine) and avoidance of alcohol or excessive wetting of the pediatric patient during the surgical site preparation will be beneficial in helping preserve body heat.^1,2 Because pediatric tissues are very friable, gentle tissue handling is mandatory. The relatively small blood volume of pediatric patients makes meticulous hemostasis very important. Fortunately, the small size of blood vessels in the spermatic cord makes precise and complete hemostasis easy to accomplish.

Pediatric castration is performed with modifications to the techniques used in adult dogs. Because puppy testes are mobile and can be difficult to identify, careful palpation is performed to determine whether both testicles have descended into the scrotal region before beginning surgery. If one or both testes have not descended, standard cryptorchidectomy techniques may be used for castration. The entire scrotal region is clipped and surgically prepared to permit the scrotum to be incorporated in the surgical sterile field. Because of the mobility and small size of the puppy testes, including the scrotum in the surgical field can facilitate locating and manipulating the testes during surgery. Clipping and surgical preparation of the scrotum does not result in scrotal irritation in puppies as it does in adult dogs because the scrotal sac of puppies is not well developed as compared to adult male dogs. Puppies are positioned on the surgery table in a similar fashion as adult males, however, it is often useful to very loosely secure the hind legs to the table so as to facilitate testis identification and palpation after draping. Puppies may be castrated through a single midline (preferred) prescrotal or scrotal incision, or through two scrotal incisions positioned similarly to a feline castration. When a midline incision is used, the testicles must be securely held underneath the incision site to prevent iatrogenic penile or urethral trauma. Following exposure of the testicle and spermatic cord in a closed fashion, (testes remain enclosed in the parietal vaginal tunic during castration), the spermatic cord is doubly ligated with 3-0 absorbable suture material or stainless steel hemostatic clips. If the parietal vaginal tunic is inadvertently penetrated and the testis extruded, an open castration technique may be performed using standard adult canine castration techniques. Adequate hemostasis should be verified prior to return of the vascular pedicle to the inguinal region. The skin incision is closed using one or two buried interrupted sutures of absorbable suture in the subcuticular layer, or the incisions may be left open to heal by second intention healing. Closure of the incision is preferred and prevents postoperative wound contamination with urine or feces, and extrusion of subcutaneous fat from the incision.

Kitten castration is performed using identical techniques as in the adult cat. Two separate scrotal incisions are used to approach the testes. When preparing the surgical site of a kitten castration, it is often easier to shave the scrotal region than to pluck the scrotal region. Positioning and draping of the kitten is identical to positioning of the adult male cat prior to castration. As with the pediatric puppy, the testes of the pediatric cat are extremely small, highly mobile, and occasionally difficult to stabilize in the scrotal region in preparation for incision. The testis should be securely stabilized in the scrotal region and the incision made directly over the testis at the ventral most aspect of the scrotal “sac”. After the incision, the testis is carefully exposed using gentle caudoventral traction. It is important to realize that the pediatric testis cannot be exteriorized to the same distance as in the adult cat without potential tearing of the spermatic cord. The closed castration technique is preferred, using a hemostat to place an overhand throw in the pedicle, or using suture or hemostatic clips for hemostasis. If the parietal vaginal tunic is inadvertently opened, an open technique using either a hemostat to place an overhand throw in the spermatic cord, or the use of spermatic cord tissues (vas deferens) for knot tying may be employed. Alternatively, sutures or hemostatic clips may be used to achieve hemostasis in an open castration. Care must be used when manipulating tissues to prevent rupture or tearing of the small and fragile spermatic cord. As with adult cat castrations, the scrotal skin incisions are left open to heal by second intention.

Postoperative Care

All animals undergoing early age castration should be tattooed to identify their neutered status so as to avoid unnecessary abdominal exploration in the future. The recommended tattoo site in males is the inguinal area. The male gender symbol along with an encircled “X” is used to denote the neutered status. Tattooing is best performed after the surgical site has been clipped but prior to the surgical prep of the area.

During recovery from anesthesia, pediatric patients should be monitored for hypoglycemia, hypothermia, pain, or dysphoria. Supplemental heat, glucose containing agents, or additional analgesics or sedatives may be used to ensure smooth recovery from anesthesia. These patients may be fed a small meal one to two hours after recovery since they tend to recover much more quickly from anesthesia and surgery.

Postoperative Complications

Veterinarians have long been concerned about the potential health risks of early age castration. These concerns have included increased risk of urethral obstruction in male cats, obesity, and abnormal long bone growth patterns in dogs and cats neutered at an early age. Concerns have also been expressed regarding the immune system of puppies and kittens and the effects of the stress of anesthesia and surgery at an early age. The development of neoplasia has also been a more recent concern. Recent studies have begun to clarify the long term health risks and benefits of early age castration as compared to traditional age castration.

Urethral, Penile, and Preputial Development in Male Cats

A major concern of veterinarians regarding performing early age neutering is that of feline lower urinary tract disease (FLUTD) and urethral obstruction in male cats. It was thought that early neutering of the male cat would result in a smaller diameter urethra thus predisposing the cat to urinary obstruction caused by FLUTD. Numerous experimental and clinical studies dating to the 1960’s have studied this concern. Recently, two experimental studies examining cats castrated at seven weeks and seven months of age as compared to sexually intact cats have studied this concern.^3,4 The first study examined urethral development when cats were one year of age, and found that urethral diameters as determined by contrast retrograde urethrography were similar among both groups of neutered cats as compared to intact cats.³ Additionally, no difference in urethral dynamic function as determined by urethral pressure profiles was seen among groups. In the second study, voiding cystograms were used to measure the diameter of the preprostatic and penile urethra when cats were 22 months of age.⁴ As in the previous study, no differences were seen in urethral diameter of male cats neutered at seven weeks or seven months of age as compared to intact cats.

In addition to experimental studies, two recent long-term clinical studies have examined the effect of early age castration on the incidence of urinary tract disease. The first long-term (37 month median follow-up) study examined 263 cats neutered at an early age (< 5.5 months) as compared to the traditional age ≥ 5.5 months.⁵ There were 108 male cats which were divided into two groups based on age at the time of castration: early age (median age at castration = nine weeks; n = 70) and traditional age (median age at castration = 51 weeks; n = 38). In that study, traditional age neutered cats had significantly more overall urinary tract problems (17%) as compared to early age neutered cats (3%). “Cystitis” was the most common problem seen, and the incidence was significantly greater in cats neutered at an older age. There was no significant difference in the rate of urethral obstruction between groups although 2/38 (5%) traditional age neutered cats suffered urinary obstruction, while 0/70 (0%) early age neutered cats became obstructed. A second recent study examined 1660 cats neutered at an early age (< 5.5 months of age) as compared to the traditional age (≥ 5.5 months of age).⁶ The median follow-up time for that study was 47 months, with follow-up available for as long as 11 years after surgery. That study found no association between the incidence of FLUTD or urethral obstruction and the age at gonadectomy.

Abnormal penile and preputial development in male cats castrated at an early age has also been a concern for many veterinarians. The balanopreputial fold is a fold of tissue (a continuous layer of epithelium) connecting the penis to the prepuce at birth. The balanopreputial fold separation process is androgen dependent and is complete at birth in some species, but not until after puberty in other species such as the cat. Concerns have been expressed that prepubertal castration in cats might delay or prevent dissolution of the membrane, and predispose to ascending urinary tract disease since these cats may not be able to fully extrude the penis for cleaning.⁷ Recent studies examining separation of the balanopreputial fold have reported conflicting results. In one study of cats castrated at seven weeks and seven months of age, it was reported that at one year of age, the penis could be fully extruded in all males.⁸ Penile spines were atrophied in those castrated at seven months, and were absent in those castrated at seven weeks of age. This is in contrast to another study reporting on penile extrusion in cats at 22 months of age.⁴ In cats neutered at seven weeks of age, the penis could not be fully extruded in any cat, while in intact cats, the penis could be fully extruded in all cats. Of the cats neutered at seven months of age, the penis could be fully extruded in 60%. In those males incapable of complete penile extrusion, only 1/3 to 2/3 of the length of the penis could be visualized. It would appear, however, based upon the long-term clinical studies of 263 and 1660 cats,^5,6 that failure of separation of the balanopreputial fold (when present) does not cause a clinical problem in cats neutered early and does not lead to an increase in the incidence of FLUTD or urinary obstruction. Should cats neutered at an early age become obstructed however, penile manipulations for catheterization may be more challenging because of smaller penile size and the inability to fully extrude the penis.

All studies reported to date indicate that urethral development and diameter in male cats is not an androgen dependent process, even though penile size and development is androgen dependent. Therefore, it would appear that concerns about FLUTD, urinary obstruction, or potential failure of separation of the balanopreputial fold are not objective reasons to delay castration in male cats.

Obesity

Obesity is influenced by a number of factors, including neuter status, and studies suggest that gonadectomized cats may gain significantly more weight than intact cats. The literature regarding whether dogs are more likely to become obese after castration is less clear.

When comparing neutered cats to sexually intact cats, intact cats were found to weigh less than cats neutered at seven months, but there was no difference between intact cats and those neutered at seven weeks.⁸ Another study^9,10 has assessed obesity by body mass index at 24 months of age in 34 cats. Body condition scores and body mass index values were higher in animals gonadectomized at seven weeks or seven months than in intact animals. This indicated that animals gonadectomized at either age were more likely to be obese than intact cats. Heat coefficient, a measure of resting metabolic rate, was higher in intact cats than in gonadectomized cats. Based on these data, the author suggested that neutered male cats require an intake of 28% fewer calories than intact males.¹⁰

In dogs, one study found no differences in food intake, weight gains, or back-fat depth among neutered (seven weeks or seven months) and intact animals during a 15-month prospective study.¹¹ A long-term study of 1842 dogs¹² actually found that the proportion of overweight dogs was lowest in the early age gonadectomized dogs, as compared to the traditional age neutered dogs.

Body and Long Bone Growth

Several research studies have refuted the concern that early neutering will “stunt” growth. In a 15-month study of 32 dogs, growth rates were unaffected by gonadectomy, but the growth period in final radial/ulnar length was extended in all neutered male dogs (neutered at seven weeks or seven months).¹¹ Thus, neutered animals were not stunted in growth but were actually slightly taller. In a similar study,⁸ 31 cats were neutered at seven weeks or seven months or left intact. Distal radial physeal closure was delayed by approximately eight weeks in neutered cats as compared to intact cats, and no differences were detected between the two groups of neutered cats, for mature radius length or time of distal radial physeal closure. A third study in cats showed that male cats neutered at seven weeks or seven months of age reached the growth plateau on average 35% later, and achieved radial length of 13% longer than intact males.¹³

The clinical significance of delayed closure of growth plates is not clear, but it does not appear to render the growth plates more susceptible to injury. In the long term studies of 263 cats,⁵ 269 dogs,¹⁴ 1660 cats,⁶ and 1842 dogs,¹² no differences in the incidence of musculoskeletal problems were seen between groups. Further, in the long term study of 1660 cats⁶ and 1842 dogs,¹² age at gonadectomy was not associated with the frequency of long bone fractures. Based on the low incidence of long bone fractures in this study, it would seem that physeal fractures are not a common problem in gonadectomized dogs and cats in general.

Long-term studies have examined the incidence of hip dysplasia and the association with age at gonadectomy. One study of 269 dogs¹⁴ found no association between age at gonadectomy and hip dysplasia, however another study of 1842 dogs¹² found that early age gonadectomy was associated with a significant increased incidence of hip dysplasia. Puppies that underwent gonadectomy before 5.5 months of age had a 6.7% incidence of hip dysplasia, while those that underwent gonadectomy at, or after, 5.5 months of age had an incidence of 4.7%. However, those that were gonadectomized at the traditional age were three times more likely to be euthanized for the condition as compared to the early age group, suggesting that early age gonadectomy may be associated with a less severe form of hip dysplasia.

In the Golden Retriever breed, one study found that when dogs were neutered before 1 year of age (early neutered) the incidence of cranial cruciate ligament rupture was greater than in those neutered after 1 year of age or remaining intact.¹⁶ When compared to intact dogs, the incidence of hip dysplasia was also increased in the male dogs of the early neutered group.

Infectious Diseases and Long-Term Immune Suppression

In the shelter environment, puppies and kittens neutered at early ages had no higher risk of infectious diseases than older animals according to one short-term (seven day) study. This study involved shelter source dogs and cats undergoing gonadectomy in association with the fourth-year student surgical teaching program at a university teaching hospital.¹⁵ Twelve of 1988 (0.6%) animals died or were euthanized because of parvovirus infection or as a result of severe infections of the respiratory tract during the seven day postoperative period, and the deaths (or euthanasias) included similar numbers of animals from all age groups.

In long term studies of 263 cats⁵ and 269 dogs,¹⁴ prepubertal gonadectomy did not result in an increased incidence of infectious disease after adoption in cats, compared with traditional age gonadectomy. In dogs, however, gonadectomy before 5.5 months of age was associated with an increased incidence of parvoviral enteritis. In more recent studies of 1660 cats⁶ and 1842 dogs,¹² those gonadectomized before 5.5 months of age were not significantly more likely than those gonadectomized after 5.5 months of age to have any conditions that might be presumably associated with long-term immune suppression. On a short-term basis, however, dogs from the study that were gonadectomized before 5.5 months had an increased incidence of parvoviral enteritis that often occurred soon after adoption. In both of the long-term dog studies^14,12 (269 dogs and 1842 dogs), the increased incidence of parvoviral enteritis on a short-term basis probably represented an increased susceptibility of the younger puppies during the periadoption period, rather than long-term immune suppression.

References

1. Faggella AM, Aronsohn MG: Evaluation of anesthetic protocols for neutering 6- to 14-week-old pups. J Am Vet Med Assoc 205:308, 1994.
2. Faggella AM, Aronsohn MG: Anesthetic techniques for neutering 6- to 14-week-old kittens. J Am Vet Med Assoc 202:56, 1993.
3. Stubbs WP, Bloomberg MS, Scruggs LS, et al.: Prepubertal gonadectomy in the domestic feline: effects on skeletal, physical, and behavioral development. Vet Surg 22:401, 1993.
4. Root MV, Johnston SD, Johnston GR, et al.: The effects of prepubertal and postpubertal gonadectomy on penile extension and urethral diameter in the domestic cat. Vet Radiol & Ultrasound 37:363, 1996.
5. Howe LM, Slater MR, Boothe HW, et al.: Long-term outcome of gonadectomy performed at an early age or traditional age in cats. J Am Vet Med Assoc 217:1661, 2000.
6. Spain CV, Scarlett JM, Houpt KA: Long-term risks and benefits of early-age gonadectomy in cats. J Am Vet Med Assoc 224:372, 2004.
7. Herron MA: A potential consequence of prepubertal feline castration. Feline Pract 1:17, 1971.
8. Stubbs WP, Bloomberg MS, Scruggs SL, et al.: Effects of prepubertal gonadectomy on physical and behavioral development in cats. J Am Vet Med Assoc 209: 1864, 1996.
9. Root MV: The effect of prepubertal and postpuberal gonadectomy on the general health and development of obesity in the male and female domestic cat. PhD Thesis, University of Minnesota, Saint Paul, MN, 1995.
10. Root MV: Early spay-neuter in the cat: effect on development of obesity and metabolic rate, Veterinary Clinical Nutrition 2:132, 1995.
11. Salmeri KR, Bloomberg MS, Scruggs SL, et al.: Gonadectomy in immature dogs: Effects on skeletal, physical, and behavioral development. J Am Vet Med Assoc 198:1193, 1991.
12. Spain, CV, Scarlett JM, Houpt KA: Long-term risks and benefits of early-age gonadectomy in dogs. J Am Vet Med Assoc 224:380, 2004.
13. Root MV, Johnston SD, Olson PN: The effect of prepubertal and postpubertal gonadectomy on radial physeal closure in male and female domestic cats. Vet Radiol & Ultrasound 38:42, 1997.
14. Howe LM, Slater MR, Boothe HW, et al.: Long-term outcome of gonadectomy performed at an early age or traditional age in dogs. J Am Vet Med Assoc 218:217, 2001.
15. Howe LM: Short-term results and complications of perpubertal gonadectomy in cats and dogs. J Am Vet Med Assoc 211(1):57, 1997.
16. De la Riva GT, Hart BL, Farver TB, et al.: Neutering dogs: effects on joint disorders and cancers in Golden Retrievers. PLOS One 8(2):e55937, 2013.
17. Cooley DM, Beranek BC, Schlittler DL, et al.: Endogenous gonadal hormone exposure and bone sarcoma risk. Cancer Epidemiol Biomarkers Prev 11(11):1434-1440, 2002.
18. Ru G, Terracini B, Glickman LT: Host related risk factors for canine osteosarcoma. Vet J 156(1):31-39, 1998.
19. Bryan JN, Keeler MR, Henry CJ, et al.: A population study of neutering status as a risk factor for canine prostate cancer. Prostate 67(11):1174-1181, 2007.
20. Sorenmo KU, Goldschmidt M, Shofer F, et al.: Immunohistochemical characterization of canine prostatic carcinoma and correlation with castration status and castration time. Vet Comp Oncol 1(1):48-56, 2003.
     

Introduction

Castration (orchiectomy) is performed frequently for reproductive neutering and for reducing or eliminating the behavior patterns characteristic of intact males. The procedure continues to be the first line of defense against the plague of animal overpopulation. Testicular neoplasia, severe traumatic injury, refractory orchitis, and epididymitis are primary medical indications for unilateral or bilateral orchiectomy. Removal of the primary endocrine sources of androgenic hormones are secondary reasons for castration in that androgens may be complicating mediators in benign prostatic hypertrophy, prostatitis, perianal adenoma, and perineal hernia. In addition, castration, coupled with scrotal ablation, is the initial surgical step in creating the perineal urethrostomy of the cat...a salvage procedure for a scar damaged urethra. Castration and scrotal ablation are the first steps in creating a permanent scrotal urethrostomy in dogs...a procedure to allow urolithic debris in urine to be discharged prior to the narrowing of the urethra within the os penis.

Surgical Anatomy

The spermatic cord must be exposed, exteriorized and transected in any castration. The cord originates at the vaginal ring as its individual components exit the abdominal cavity. In the center of the spermatic cord are the mesorchium, the testicular artery, the testicular vein and the associated pampiniform plexus. The lymphatic vessels, deferent duct and the testicular plexus of autonomic nerves complete the structure. Externally, the cord is wrapped in a double tunicae of the vaginal process which is covered by the spermatic fascia, an extension of the fascia of the abdominal wall. Between the visceral and parietal layers of the vaginal process the cavity is continuous with the peritoneal cavity. Two thin layers of spermatic muscle overlay the tunicae as flat extensions of the internal abdominal oblique muscle. The muscle runs along the external surface of the parietal tunica of the vaginal process to insert on the spermatic fascia and parietal vaginal tunic. Surgically, the cremaster is considered and handled as though it were part of the spermatic cord. Between the subcutaneous inguinal ring and the scrotum, the spermatic cords pass ventral and medial to the thigh adductor muscles in a subcutaneous position. When the spermatic cords are delivered into a surgical incision they are often covered with a thin layer of fat.

Surgical Preparation for Castration of the Dog

Canine orchiectomy is performed under general anesthesia with the dog positioned in dorsal recumbency and with tethering restraint of the pelvic limbs in a caudal direction. The hair of the prescrotal and medial thigh areas is clipped and these areas and the scrotum are washed with water and mild soap. The prescrotal area of the prepuce, but not the scrotum itself, is then further prepared for aseptic surgery with skin preparation soap and solution. (Should the scrotum be prepared with antiseptics there is a high incidence of contact dermatitis). Because the scrotum has not received aseptic preparation the fully prepared prescrotal operative field is quadrant toweled to cover the scrotum. A fenestrated drape is positioned over the prescrotal area and the remainder of the patient. All further manipulations of the testes and scrotum are performed through the sterile fabric layers of the towel and drape.

Surgical Procedure for Castration of the Dog

To begin the orchiectomy a skin and subcutaneous incision is made on the ventral midline of the prepuce at the cranial base of the scrotum (Figure 35-1). The length of the incision must allow for the outward expression of each testis (Figure 35-2A). Next, one testis is manipulated forward and into the incision by pressure on the scrotum through the drape and towel. The tissue that limits the outward extrusion of the testis at this point is the spermatic fascia which must be incised down to the parietal layer of the vaginal tunica. The latter structure is a white, dense glistening layer of fascia that closely surrounds the testis. Once the spermatic fascia has been divided, the tunica covered testis can be delivered (“popped”) forward, outward and into the skin incision (Figure 35-2B). Shortly after the testis appears, however, its outward progress is again resisted this time by the additional attachment of the spermatic fascia which connects the tail of the epididymis to the scrotal wall. This ligament may be broken by traction but often requires isolation by blunt dissection and, then, sharp transection. Using a hemostatic forceps across the ligament to crush small vessels is good practice in younger dogs and is often sufficient for hemostasis. However, in the case of mature adults, testicular neoplasia or orchitis, the ligament should be ligated to preclude the potential complication of postoperative scrotal hematoma. After clamping or ligation of the ligament of the tail of the epididymis, the structure is divided to release the invagination of the scrotal skin and to allow further exteriorization of the testis (Figure 35-3). Steady caudal and outward traction is next applied to the testis to break down connective tissue attachments between the spermatic cord and the spermatic fascia. As the cord emerges into the operative field, any fat around the cord is removed by a proximal wiping and stripping action with a moist sponge. At this stage, the testis and a considerable portion of the spermatic cord have been exteriorized and the cremaster muscle is dearly seen on the external surface of the vaginal tunicae. The technique for cord transection depends on the patient’s size.
 

Closed Castration

In patients under 20 kg, a “closed” castration technique is used. “Closed” means that the contents of the spermatic cord are triple clamped, ligated, and divided with the tunicae of the vaginal process intact around the cord (Figure 35-4). Additionally, the vaginal process is transfixed to the cremaster muscle to provide extra security in ligation. After triple hemostatic forceps are applied to the proximal portion of the exposed cord, the most proximal clamp is removed, and a slowly absorbable suture material, swaged to a taper needle, is passed through the cremaster and tunica (Figure 35-5A). In placing this transfixation ligature, the surgeon must take care to miss the vascular structures of the spermatic cord. The ligature is tied over the cremaster and the ends of the suture are passed in opposite directions back around the spermatic cord to encircle it before forming a final knot (Figure 35-5B and Figure 35-6). The transfixation method of securing the hemostatic ligature prevents loosening or shifting of the ligature if the cremaster should contract. Ligature loosening could cause a retraction of the testicular artery away from ligature control. The middle clamp is removed and a second, non-transfixing ligature is placed in the clamp’s crush mark. The spermatic cord is severed along the proximal edge of the distal clamp to prevent backfiow hemorrhage from the testis into the operative field (See Figure 35-6).
 

Open Castration

The “open” castration method is used for dogs over 30 kg. After each testis is exteriorized as described previously, the vaginal process is incised and opened longitudinally with scissors to expose the internal structures of the spermatic cord (Figure 35-7).

Proximally, most of the vaginal process and cremaster muscle are amputated; they are ligated only if large blood vessels are present. In returning to the spermatic cord itself, the testicular artery and vein and the deferent duct are ligated according to triple-damp technique with slowly absorbable suture material and are divided (Figure 35-8 and Figure 35-9). The advantages of the open method are that the vascular ligations are direct and, thus, more secure. The disadvantage is opening of an extension of the peritoneal cavity and a longer operative time.

After the spermatic cord is divided in either the open or closed castration technique, the remaining portion of the cord is released proximally into the subcutaneous tissue under direct control of thumb forceps (Figure 35-10). Control during the release of the cord is important because the vessels shorten and dilate as tension on them is released. Any ligature slippage and hemorrhage will probably occur at this time. If bleeding occurs, the vessels or cord can be immediately retrieved for further attention if held by thumb forceps.
 

The remaining testis is produced by incising the contralateral spermatic fascia and the second gonad is removed in the same manner to complete the castration. At no time is invasion of the scrotal wall or scrotal septum necessary and any incision into the scrotum or the septum invites the complication of scrotal hematoma. After inspection for the complete arrest of bleeding, the deep and superficial subcutaneous layers and the subdermal skin are closed in one layer with an absorbable suture material. A simple interrupted or continuous pattern can be used but several of the suture bites should be placed laterally and deeply enough to “pick up” the connective tissue surrounding the retractor penis muscle to ablate potential dead space. Finally, the skin edges are gently and loosely apposed with a fine, nonabsorbable suture material in a simple interrupted pattern (Figure 35-11). Skin sutures that are placed too tightly often attract postoperative licking or self mutilation. In this case sutures will need to be removed if they are “cutting through” and can be replaced. New, looser skin sutures may also be complemented by the use of restraint devices such as a head collar or side bars, tranquilization, or topical preparations that are bitter to the taste. Skin edges can also be opposed with fine staples or surgical adhesive.

Editor’s Note: Intradermal closure of the skin is practiced by many surgeons instead of skin closure as it is believed that self-trauma of the incision by licking is less of a postoperative problem when skin sutures are omitted.
 

Ancillary Techniques to Orchiectomy

Scrotal Ablation

Veterinarians and clients may prefer scrotal ablation in the opinion that it cosmetically complements the orchiectomy. This is especially true in larger breed dogs with short hair coats. Preperation for surgery includes full antiseptic scrubbing of the scrotum and the inner thigh and perineal areas. Scrotal ablation is initiated by a circumfrential incision around the scrotum with the incision made slightly toward the scrotal side of the junction between the skin. Such an incision placement reduces skin tension and utilizes incision-induced spasms of the tunica dartos layer of the scrotum to help reduce intra-operative hemorrhage. The incision is extended through the entire subcutaneous tissue by sharp dissection where pinpoint electrocautery may be useful. After removal of the scrotum and following orchiectomy, attention to dead space ablation during the subcutaneous layer closure is important.

Implantation of Testicular Prostheses

Alternatively to scrotal ablation, veterinarians and clients may prefer preserving the appearance of a natural scrotal and testicular anatomy. In this case prosthetic testicular implants are available in various sizes, firmnesses and degrees of anatomic correctness. The implantation technique is a patented procedure and is described in literature supplied by the manufacturer of the implants. As with any implanted bioprosthesis strict adherence to aseptic technique is a critical facet of the procedure.

Orchiectomy Through a Caudal Approach

A caudal approach is a choice for canine orchiectomy when the patient is already positioned in sternal recumbency on a “head-down” elevated platform for perineal surgery (see pages 581-582). Before the other perineal procedure is performed a transverse incision is made dorsal to the scrotum at its junction with the perineal skin. After the spermatic fascia is incised, the testes are delivered dorsocaudally into the operative field by upward pressure on the toweled scrotum. With outward traction applied the ligament of the tail of the epididymis is identified, isolated, clamped, and divided. The spermatic cord and testis are then delivered into the incision and the remainder of the operation is performed as previously described for a closed or open technique.

Castration of the Cat

Male cats are usually neutered at or before sexual maturity. The intact male cat is usually not well tolerated as an indoor companion animal because of marking and spraying with an odoriferous urine. Nocturnal fighting and roaming are other behavior patterns of male cats that are often successfully controlled by orchiectomy.

The only instruments needed for cat castration are two mosquito forceps, a pair of smaller, sharp sharp scissors, a No. 10 scalpel blade, absorbable ligature material, and a nonfenestrated paper drape. The cat is placed under ultrashort acting general anesthesia and positioned in dorsal, ventral, or lateral recumbency. While in dorsal recumbancy the cat’s perineal area is conveniently exposed by bringing the hindquarters to the edge of a table and allowing the tail to fall toward the floor. The patient’s pelvic limbs are secured in a laterally abducted position, and the hair covering the scrotum is either plucked with the fingers or clipped with a No. 40 clipper blade. The scrotal area is prepared with scrub soap and skin antiseptics. A drape is easily and economically made from paper drape material that is sterilized with the other instruments and a fenestration about the size of a dime is cut in the center of the drape. The prepared scrotum is expressed through the hole to create an acceptably draped surgical area without any exposure of hair.

The skin, tunica dartos and spermatic fascia over each testis are vertically incised with a No. 10 scalpel blade. The incision should extend amply from the dorsal to the ventral aspect of the scrotal compartments. With a pinching maneuver the testis, still enclosed in the vaginal process, is “popped” out of the incision. The testis is pulled caudoventrally until considerable exposure of the spermatic cord is obtained and resistance to further traction is met. Any fat investing the spermatic cord is stripped from the cord and, in a proximal position, two Halstead mosquito forceps are placed across the spermatic cord. As the proximal forceps is removed a ligature of absorbable suture material is tied tightly in the crush mark. The spermatic cord is then transected and released up into the scrotum under direct control of the remaining mosquito forceps. As an alternative to ligature placement, kittens and juveniles, but not adults, can have their spermatic cord looped with an overhand knot and cinched tight (Figure 35-12). After the testes are removed, both scrotal incisions are dilated by spreading the tips of mosquito forceps between the wound edges to preclude an early fibrin seal across the incision. The application of topical ointments or systemic antibiotics are unnecessary.
 

Cryptorchidism

Unilateral or bilateral cryptorchidism is encountered frequently in dogs and is transmitted as a hereditary disorder in a simple, autosomal recessive manner. The condition occurs most frequently in small purebred dogs, with a right to left ratio of 2.3:1. Unilaterally cryptorchid males are typically fertile and possess normal libido so the trait is widely disseminated.

Testicular descent should be complete shortly after birth and testes not located within the scrotum by 2 months of age should be considered permanently retained. Veterinarians should strongly recommend the castration of cryptorchid animals because testes retained in an inguinal or abdominal position are predisposed to the malignant changes of seminoma and Sertoli cell tumor. Orchiopexy or prosthetic testicular implantation is illegal and unethical for show purposes and can contribute to the perpetuation of cryptorchidism.

The palpable absence of one or both testes during several examinations confirms the diagnosis of cryptorchidism. Once a diagnosis of cryptorchidism has been established, the surgeon must determine at what point along the normal path of testicular descent migration became arrested. This point can be anywhere from just cranial to the scrotum in the subcutaneous tissue of the groin all the way up to the position of embryonic organogenesis just caudal to the kidney. Careful palpation usually enables the examiner to detect most gonads if they are distal to the superficial inguiinal ring in the subcutaneous tissue of the groin.

Many retained canine testes are located within the abdominal cavity and exploratory celiotomy or laparoscopy is required for their removal. With the patient under general anesthesia and the ventral abdominal wall prepared for aseptic surgery, a midline celiotomy is performed through the linea alba from the umbilicus to the prepuce. Frequently, the testis is located in the mid abdominal region as a highly movable organ smaller than the descended gonad. Arterial supply from the testicular artery, a direct branch of the aorta, and a small artery in the gubernacular remnant or the deferential fold of the peritoneum are typically visualized. Also, the ductus deferens courses toward the caudal aspect of the abdomen and can be a reliable primary landmark for tracing to the retained testis.

If the testis cannot be located initially in the mid abdominal area, the area of the inguinal ring is next examined. When testicular descent is arrested at this location, the testis can usually be palpated by moving a finger along the abdominal wall toward the ring. After the cryptorchid testis is located, the testicular vessels and ductus are isolated, triple clamped, and doubly ligated either collectively or individually with a slowly absorbable ligature material. After division of vascular structures, the abdominal cavity is checked carefully for bleeding, and the celiotomy is closed. True agenesis of the testis and vas deferens is reported, but it is rare. If the testis has descended through the inguinal canal and is located in the subcutaneous tissue of the groin, removal is by a standard prescrotal incision with manipulation of the testis into the incision by digital pressure.

Selected Readings

Baumans V. Dijkstra G, Hensing CJG. Testicular descent in the dog. Zentralbi Veterinaermed [A] 1981;1O:97.

Evans HE. Miller’s anatomy of the dog. 3rd ed. Philadelphia: WB Saunders, 2005.

Hates HM, Wilson GP, Pendergrass TW, et al. Canine cryptorchidism and subsequent testicular neoplasia: case control study with epidemiologic update. Teratology 1-85;32:51.

Hudson LC, Hamilton WP. Atlas of feline anatomy for veterinarians. Philadelphia, WB Saunders, 1993.

Knecht CD. An alternative approach for castration of the dog. Vet Med Small Arnm Clin 1976;71:469.

Reif JS, Moquire TG, Kenney RS. A cohort study of canine testicular neoplasia. J Am Vet Med Assoc 1979;175:719.