Step by Step: Vasectomy

Article provided by Vetlexicon Canis.

Contributors Agata Witkowska and Autumn P Davidson

Images Robert J. McCarthy

Rationale for technique

To remove and/or occlude a portion of the ductus deferens to prevent spermatozoa from being ejaculated during copulation and thus render the male infertile.
For the purpose of this article only open surgical vasectomy technique is described.

Uses

Gonad-sparing neutering technique.

Advantages

Preservation of sexual drive and behaviors which may be desirable in some cases, eg police dog.
Alternative to gonadectomy Castration permitting maintenance of gonadal endocrinologic function.
Preservation of physical appearance.

Disadvantages

Sexual drive and behaviors are retained leading to undesirable habits such as territorial marking, mounting and aggression.
Long-term studies evaluating benefits of gonadectomy versus vasectomy are ongoing.
Requires some basic to moderate surgical experience to ensure sufficient spermatic duct is removed or occluded to guarantee sterility.
Vasectomy is often a lengthier procedure than traditional gonadectomy and carries a higher risk of failure and complications. Vasectomy is not generally reversible. Both should be discussed with the owner in the pre-surgical assessment.

Technical problems

Initially vasectomy may take longer for the beginner/inexperienced surgeon prolonging anesthetic time.
Requires good anatomical knowledge.
Overweight and obese animals are likely to have more inguinal fat hindering easy localization of the spermatic cord. This can be overcome by manipulation of the testicle in a cranial and caudal direction to tense the cord which may ease visualization during subcutaneous dissection.

Alternative techniques

Leaving the animal intact.
Surgical gonadectomy Castration.
Medical castration – eg GnRH agonist implants (Supralorin) Deslorelin.
Chemical vasectomy.

Time required

Preparation

Standard surgical scrub and sterile technique is required Surgical asepsis and scrubbing.

Procedure

10-20 min for an experienced soft tissue surgeon.

Decision taking

Criteria for choosing procedure

Where alteration of physical appearance is not desirable.
Where retention of sexual drive is desirable.
Where decreased risk of pregnancy is important in multi-dog households, but early castration is not desirable, eg young giant breeds of dogs.
Before vasectomy is performed it is important to perform a full clinical exam and consider testicular ultrasonography Ultrasonography: testes to ensure no pre-existing reproductive pathology is present. The testes, epididymi and prostate should be palpated and possibly evaluated ultrasonographically Ultrasonography: prostate.

Risk assessment

Desirability of retaining sexual behavior and the ethics of this should be considered. Clients should be warned of this and gonadectomy discussed as an alternative.
Risk of anesthesia, hemorrhage, infection and wound breakdown.
Risk of procedure failing and accidental pregnancies if the male is in contact with intact bitches.
Risk of scrotal and testicular discomfort secondary to epididymal fluid extravasation and/or formation of a sperm granuloma. Subsequent scrotal dermatitis can occur.
Semen peritonitis has been reported.

Requirements

Personnel

Veterinarian expertise

Basic surgical expertise.
Understanding of the anatomy.

Other involvement

Owners are required to monitor patients for post-operative wound interference, swelling, breakdown and infection. A period of post-operative confinement/rest is advised.

Materials required

Minimum equipment

Standard soft tissue dissection/basic surgery kit is sufficient.

Ideal equipment

Magnification loupes for smaller individuals, eg miniature dog breeds.
Ophthalmologic surgical pack with fine instruments.

Minimum consumables

Monofilament, absorbable suture such as polydioxanone in sizes 4-0 to 0 for giant breeds is the author’s choice.

Preparation

Pre-medication

Depending on pre-anesthetic ASA grade, standard pre-medication combination may be used as in case of surgical neutering. Because both sedation and analgesia should be provided, general anesthesia is advised General anesthesia: overview.

Dietary preparation

The decision on how long an animal should be nil-by-mouth prior to surgery rests with the veterinary surgeon and is decided on a case-by-case basis based on factors such as age, size, health, etc.

Site preparation

Clip the prescrotal and cranial scrotal area carefully as per routine pre-scrotal castration.
Routine skin preoperative preparation Surgical asepsis and scrubbing.

Other preparation

Once the animal has been anesthetized and blood pressure measurements performed Arterial blood pressure: oscillometric and found satisfactory, administer additional analgesia in the form of non-steroidal anti-inflammatory drugs intra or post operatively such as Meloxicam Meloxicam at 0.2 mg/kg loading dose subcutaneously.
Consider a multimodal analgesia approach incorporating the use of subcutaneous local anesthetics such as lidocaine Lidocaine and bupivacaine Bupivacaine at incision sites.
Although vasectomy carries a lower risk than castration, consider pre-anesthetic lungworm/heartworm testing Angiostrongylus if in an endemic area.
Gently manually empty the bladder.

Restraint

Restrain for intravenous catheter placement or intramuscular pre-medication/anesthesia administration as standard.
The dog or cat is placed in dorsal recumbency for the procedure.

The patient is clipped, scrubbed and draped as shown.

Step 1 – Make a pre-scrotal incision

The spermatic cords can be palpated either side of the usual pre-scrotal midline incision (as performed during routine castration). These can be felt subcutaneously and if hard to find (overweight animals) the testicles can be manipulated cranially and caudally within the scrotum in a cranial and caudal direction to better visualize them. This technique can also be used once the incision is made if localization is difficult.
Make a 1-3 cm midline pre-scrotal incision cranial to the scrotum.
Alternatively, two incisions over each vas can be made. Image © Robert J. Mc

Step 2 – Dissect off the midline incision

Make a lateral dissection either side of the mid-line incision to identify the spermatic cord.
If abundant subcutaneous fat is present retractors may be useful.

Step 3 – Identify the spermatic cord

The spermatic cord is made up of the ductus deferens (vas deferens) and the associated artery as well as the testicular artery.
The cord is covered in the tunica vaginalis.
Image © Robert J. Mc

Once identified, the cord is undermined with a pair of hemostats for gentle dissection. Image © Robert J. Mc

Step 4 – Incise the tunic vaginalis

Taking care not to damage the pampiniform plexus, make an incision into the tunic at proposed vasectomy site.
Blunt dissection can be used for this.

Step 5 – Excise a portion of the ductus deferens

The ductus deferens (sperm duct) appears as a white tubular structure and is easy to differentiate from surrounding vasculature.
Place two encircling ligatures 1-2 cm apart using fine absorbable suture(or coated multifilament sutures like polyglactin 910 (Vicryl, Ethicon) or polydioxanone (PDS, Ethicon)) in sizes 4/0-2/0 depending on the size of the patient.
Following this, excise the proposed portion of the duct

Section excised. The use of hemoclips is just for visualization. Suture ligation is generally used. Image © Robert J. Mc

Recanalization has been reported if a duct is simply severed.

Step 6 – Close the incision and repeat the procedure on the contralateral side

Using the same steps repeat the procedure on the contralateral side.
The parietal vaginal tunic is closed also with fine absorbable sutureand the skin is closed with an absorbable suture in a subcuticular pattern. The procedure is then repeated on the opposite side if two incisions were elected.
Incision in the tunic does not need to be closed. As the testicle has not been excised, there is no risk of organ prolapse via the inguinal canal.
Inspect for bleeding and if none present, close the subcutaneous space with a simple interrupted or continuous pattern using the same suture materials as proposed above.
Close the skin with an intradermal suture pattern. The author advises poliglecaprone 25 in size 4/0-3/0 depending on the size of the patient ensuring all sutures are buried. This reduces the risk of post-operative interference.

Retain the excised tissue

To ensure the spermatic cord has been resected the tissue can be preserved on a microscopic slide, sent for histopathology and in house cytology of contained material performed in house to visualize sperm.

Aftercare

Immediate aftercare

Monitoring

Recovery is routine, as for patients who have undergone neutering.
Ensure a medical pet t-shirt, buster collar, Elizabethan collar or comfy collar has been applied to reduce the risk of post-operative wound interference by the patient.
Ensure the patient is monitored and TPR performed every 15 minutes for the first hour of anesthetic recovery.

Analgesia

Analgesia in the form of non-steroidal anti-inflammatory drugs, when appropriate, or gabapentin Gabapentin may continue for 3-5 days post-operatively.

Antimicrobial therapy

None required for routine surgery.

Potential complications

Wound breakdown and infection.

Azospermia in the dog can take a period of 5 days to 4 weeks, the owner should be made aware of this.

Outcomes

Complications

Wound breakdown and infection.
Complications associated with poorly monitored anesthetic recovery such as hypothermia Hypothermia.
Sperm granulomas have been reported in dogs where inappropriate ligation of epididymal tail rather than vas deferens has occurred. This may result in testicular dilation and necrosis requiring surgical castration.
Chronic scrotal dermatitis has also been reported following vasectomy in dogs.

Prognosis

Good to excellent.

Reasons for treatment failure

Poor surgical technique and rough tissue handling resulting in granuloma formation and wound breakdown.
Amputation of incorrect structures.
Infection and wound breakdown associated with lack of operative sterility and post-operative interference.

Rationale for technique

Uses

Advantages

Disadvantages

Technical problems

Alternative techniques

Time required

Preparation

Procedure

Decision taking

Criteria for choosing procedure

Risk assessment

Requirements

Personnel

Veterinarian expertise

Other involvement

Materials required

Minimum equipment

Ideal equipment

Minimum consumables

Preparation

Pre-medication

Dietary preparation

Site preparation

Other preparation

Restraint

Step 1 – Make a pre-scrotal incision

Step 2 – Dissect off the midline incision

Step 3 – Identify the spermatic cord

Step 4 – Incise the tunic vaginalis

Step 5 – Excise a portion of the ductus deferens

Step 6 – Close the incision and repeat the procedure on the contralateral side

Retain the excised tissue

Aftercare

Immediate aftercare

Monitoring

Analgesia

Antimicrobial therapy

Potential complications

Outcomes

Complications

Prognosis

Reasons for treatment failure

Further Reading

Publications

Refereed papers

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