Ch 111 Testes, scrotum Flashcards
anatomy
- epididymis connects the testicle to the vas deferens
- epididymal tail is attached to the testis by the proper ligament of the testis
- The spermatic cord: ductus deferens + artery and vein, testicular artery, pampiniform plexus, lymphatic vessels, nerves, and cremaster muscle
- The right testicular vein drains into the caudal vena cava, and the left testicular vein drains into the left renal vein.
- Testicular and epididymal lymphatics drain into the lumbar lymph nodes
- Within each scrotal sac is an evaginated pouch of peritoneum = vaginal process (covered by the external and internal spermatic fascia).
- Deep to the spermatic fascia are the outer parietal, and inner visceral tunics.
- Between these tunics is a cavity that is continuous with the peritoneal cavity at the external inguinal ring.
- Deep to the visceral vaginal tunic is the dense shiny white capsule of the testis called the tunica albuginea
What are the three layers of the scrotum?
Skin
Tunica dartos
Scrotal fascia
What are the three different cell types which make up the seminiferous tubules within the testes?
Spermatogenic cells
Sertoli (sustentacular) cells
- Support development and maturation of spermatozoa
- Controls release of spermatazoa into tubules
- Form the blood-testis barrier
- Stimulated by FSH, negative feedback via inhibin
Leydig cells
- Lie within spaces between seminiferous tubules
- Produce testosterone
- Negative feedback with LH
What is the function of the epididymis?
Stores spermatazoa until they are released with ejaculation
What are the secondary sex glands of the dog and cat?
Dog: prostate
Cat: prostate and bulbourethral glands
Produce seminal fluid
What structure is responsible for the migration of the testis into the scrotum?
The gubernaculum
What tests can help to differentiate anorchism from bilat cryptorchidism?
- After administration of hCG, testesterone should rapidly rise if a testicle is present
- Cats have testerone-dependant penile spines which should dissappear within 6wk of castration
What cause cryptorchidism?
How old should animals be before a final diagnosis is made?
What breeds are overrepresented?
- Abnormalities of the gubernaculum
- 6 months old
- Chihuahua, Min Schnauzer, Pom, Poodles, Shelties, Huskies, Yorkies and Persian cats
What secondary complications are seen with cryptorchidism?
Dogs:
- Neoplastic transformation 9.2-13.6%
- Hip dysplasia
- Patellar luxation
- Defects of penis and prepuce
- umbilical hernia
Cats:
- Patellar luxation
- Shortened or kinked tail
- Tetralogy of Fallot
- Tarsal deformities
- Microphthalmia
- Upper eyelid agenesis
List the most common forms of testicular neoplasia
Interstitial (Leydig) tumour
Sertoli tumour
Seminomas
What syndrome is commonly seen with Sertoli cell tumours?
- Feminisation syndrome in 9.2-13.6% (significant increase in oestradiol/testosterone ratio)
- Myelotoxicosis can be irreversible and fatal
ddx
- scrotal hernia,
- orchitis,
- epididymitis,
- testicular torsion,
- spermatocele, varicocele, hydrocele,
- hematoma,
- abscess,
- sperm granuloma
- scrotal mass (MCT, melanoma, hamartoma, HSA etc)
Both testicles must be carefully palpated because the incidence of bilateral involvement
What concurrent abnormalities can be seen with Leydig tumours?
Assoc with increase testosterone production
- Perineal hernias - 15%
- Perianal adenomas - 37.3%
- Perianal gland adenocarcinoma - 9%
What is the metastatic rate of each testicular tumour?
- Sertoli 6.38-11%
- Leydig - very rare
- Seminoma - ?
Prognosis excellent with bilateral orchiectomy if no mets and no myelosuppression
List causes of epididymal occlusion
List causes of epididymal occlusion
- Aplasia (developmental failure fo the mesonephric (Wolffian) duct)
- Acquired duct occlusion
- Abnormal position of the epididymis in relation to the testis
Bileratel orchiectomy!
scrotal neoplasia
MCT - Staffys, Boxers, Beagles, Boston Terriers, viszlas
Melanomas - Schnauzers, Golder Ret
Histiocytoma - Beagle, Boxer
HSA - Goldern Ret, Boxer
How long does it take for plasma testosterone to decrease after bilateral orchiectomy?
Dogs: 2-12hr
Cats: 24-96hr
List some potential detrimental effects of castration
- Higher risk for bladder and prostate cancer
- Higher risk of OSA in Rottweilers castrated before 1yo
- Increased risk of LSA and joint dz in Golden Ret castrated before 1yo
- Castration under 6m doubled the incidence of joint disease in Golden Ret
Caution should be used when critically evaluating such studies because the cases in some studies9,12 were drawn from secondary and tertiary veterinary referral centers, which may not represent the canine population at large
neutering
- There is little scientific evidence to support that 6 to 9 months is the optimal age for neutering
- Based on short- and long-term studies of dogs and cats, gonadectomy at early ages (<24 weeks) does not increase morbidity, mortality, musculoskeletal disorders, genitourinary disorders, gastrointestinal disorders, obesity, or physical/behavioral problems compared with animals gonadectomized at later ages
castration serves as a treatment, preventative, or adjunct treatment for:
- perianal adenomas,
- prostatic abscesses,
- prostatitis,
- benign prostatic hyperplasia (BPH),
- prostatic cysts
- sex hormone–associated alopecia
List options of non-surgical sterilisation
- Zinc gluconate most common (used in puppies 3-10mo with testes 10-27mm wide)
- Testosterone agonist
- LH- releasing hormone agonist
- Glycerol
List options for castration in cats
- Overhand haemostat technique
- Figure-of-8 haemostat technique
- Suture or haemoclip attenuation
- Square knot open technique
What approaches can be used for a vasectomy?
Inguinal
Caudal midline abdominal
Abdominal laparoscopic-assisted
Prescrotal
Scrotal
What 2 structures can be used to locate an intrabadominal cryptorchid testical?
- Vas deferens from the prostate
- Testicular artery and vein from level of kidneys
Spay hooks NOT recommended - documented prostatectomy and partial prostate, urethral and ureteral avulsions
What vessel needs to be ligated when making a parapreputial approach to the abdomen?
Preputial braches of the external pudendal vessels
How many ports for a laparoscopic cryptorchid castration?
2-3 post technique
SILS
Surgical Complications
- infection,
- scrotal bruising,
- incisional hemorrhage,
- scrotal or incisional swelling,
- scrotal hematoma
- Intraabdominal hemorrhage can be a life-threatening
Delayed postoperative bleeding, 36 to 48 hours after surgery, has been reported in 26% of racing Greyhounds (Bleeding tendencies can be predicted by thromboelastography)
Single-port laparoscopic-assisted abdominal
cryptorchidectomy in 14 dogs
David 2023
Prospective case series.
10-mm single-port endoscope placed in the midline
immediately cranial to the prepuce, the spermatic cord was ligated extracorporeally
Median surgical time for unilateral abdominal
cryptorchidectomy was 17 min (range, 14–21 min) and for bilateral abdominal
cryptorchidectomy 27 min
One major intraoperative
complication (testicular artery hemorrhage) 7% occurred that required emergency
conversion and two minor entry-related complications were observed.
Neutering is not associated with
early-onset urethral obstruction in cats
Sampaio 2022
Of 84 cats with signs of UO included in this study, 28.6% were classified as intact, 28.6% as prepubertal neutered and 42.8% as post-pubertal neutered
It appears that intact cats had an earlier onset of UO than neutered cats, regardless
of age at neutering.
Pediatric neutering represents a useful tool in the control of abandoned and stray animals and the consequent dissemination of zoonoses, thus having a positive impact on public health
Evaluation of sutureless scrotal castration
for pediatric and juvenile dogs
Kirk P. Miller 2018
400 shelter-owned dogs
hemostat was twisted to form a simple overhand
knot in the spermatic cord
Results suggested that SLSC as evaluated was safe and significantly faster
than TPSC when performed in healthy 2- to 5-month-old dogs
No hemorrhage-related complications
