Common surgical procedures Flashcards
Indication for vasectomy
Cattle: preparation of teaser animals for heat detection
Sheep: teasers to stimulate oestrus in ewes to advance and/or synchronise breeding
Restraint and anaesthesia needed for vasectomy
sedation, local anaesthesia and low spinal epidural
Cattle: may be done standing or in lateral recumbency
Sheep: Usually in dorsal recumbency
Surgical technique of vasectomy
clipping and scrubbing
3-8 cm incision made over the spermatic cord between the testicle and the inguinal ring
spermatic cord is isolated and exteriorised
1cm incision is made through the vaginal tunic
section of the vas deferens is isolated with haemostats. Two ligatures using fine absorbable suture is placed approximately 3cm apart on the exposed vas deferens
section of the vas deferens between the ligatures is removed
ends of the vas deferens can be folded over and sutured or can be cauterised
spermatic cord may be closed with one suture of absorbable material or may be replaced without suturing
skin incision is generally closed in two layers
Post operative care of vasectomy
Allow 6 weeks or six ejaculates to evacuate viable semen
Skin sutures are removed in 14 to 21 days
ensure that the portion of tissue removed is vas deferens
Indication of epididymectomy
Less commonly used method of preparing teaser animal and more likely to be performed in cattle
Restraint and anaesthesia for epididymectomy
standing or in lateral recumbency under sedation for cattle
dorsal recumbency for sheep
Local anaesthetic is infused in the scrotal skin directly over the epididymis
Surgical technique for epididymectomy
clipped and scrubbed
skin incision is made in the scrotum over the tail of the epididymis
tail of the epididymis is bluntly dissected from the testicle and ligated
tail of the epididymis is resected and removed
skin is sutured
Indication for tracheotomy
Treatment of conditions that result in temporary or permanent obstruction of the larynx or nasal passage
Restraint and anaesthesia for tracheotomy
Adult cattle: Standing restraint is recommended, with the head pulled up and extended dorsally using a halter and nose lead rope, using two halters and tying either side to straighten head.
Small ruminants and calves: animal in dorsal recumbency and restraining the head is appropriate.
Sedation and analgesia are useful but must be used with care due to respiratory stress in some cases. Local anaesthesia of site is used as cases are a poor risk for general anaesthesia.
Surgical technique for tracheotomy
ventral cervical region (cranial one-third of the neck) is clipped and surgically scrubbed
head is extended upwards
trachea is stabilised with fingers
skin is incised midline over the tracheal rings
annular ring between 2 tracheal rings is punctured using a scalpel
one or two rings are cut with scissors to remove a section from 2 adjacent tracheal rings
Insert and stabilise tube in trachea
tube is inserted several centimetres into the trachea and sutured to anchor the tube
Post operative care for tracheotomy
tube should be checked for patency and retained in place until the primary disease is alleviated
Antibiotics and NSAIDs
When the tube is removed the sutures are cut and the tube pulled out, any necrotic tissue of the incision edge is debrided
Tracheostomy
a permanent opening in the trachea. This is considered a salvage procedure to get a severely dyspnoeic animal to slaughter
Indication for tibial neurectomy
Treatment of spastic paresis in cattle
Anaesthesia and restraint for tibial neurectomy
performed in lateral recumbency under sedation and epidural anaesthesia, or general anaesthesia may be used
Surgical procedure of tibial neurectomy
surgical site is initially identified and marked- the groove between the two heads of the biceps femoris
the popliteal lymph node is a useful landmark adjacent to both tibial and peroneal nerves
wound retractor is useful to expose surgical site
About 2cm length of main truck of the tibial nerve is removed as precise identification of gastrocnemius branches is difficult or impossible
If the condition is bilateral there needs to be a gap of 8 weeks rest before correcting the condition in the other limb
Post operative care for tibial neurectomy
Encourage limited exercise for 2 weeks
Complications of tibial neurectomy
usually a good prognosis following neurectomy
Complications include continuing muscle atrophy, temporary or persistent peroneal paralysis, and wound breakdown
Gastrocnemius rupture may occur in heavy cattle 1-5 days after neurectomy
Indication for gastrocnemius tenectomy
Alternative method for treatment of spastic paresis. Only temporary successful in young calves under 9 months
Anaesthesia and restraint for gastrocnemius tenectomy
Performed on standing animal using local anaesthetic
Surgical procedure of gastrocnemius tenectomy
area over the calcanean tendon 10cm proximal to the point of the hock is clipped and scrubbed
skin incision is made 6cm long vertically over the caudal aspect of the tendon
gastrocnemius tendon is located and cut transversely or a 2cm portion is removed
The adjacent superficial digital flexor tendon is also cut through half of the transverse diameter. The skin is sutured.
Following surgery there is a mark dropping of hock on weight bearing.
Complication of gastrocnemius tenectomy
Some calves may develop fibrous union of operated area, leading to recurrence 2-3 months later
Indication for teat surgery
Teat lacerations are an emergency and should be cleaned, sutured or bandaged as soon as possible (within 6 hours) to reduce contamination and inflammation.
Some obstructions will require immediate treatment, whilst others may be left and not corrected until the dry period
Restrain and anaesthesia for teat surgery
Usually standing sedation.
Roll-over crushes are useful.
For anaesthesia of the teat methods include local anaesthetic into teat canal and ring block at the base of teat.
Basal teat obstructions
Congenital in heifers or from adhesions due to chronic inflammation from infection in dry period.
Use Hudson’s teat probe and spiral to clear obstruction.
Mid teat obstructions
Chronic inflammation, milk calculi (teat peas), neoplasia (bovine papillomatosis).
Break into fragments and remove lesions via the streak canal using Barrett’s papillotome.
Larger lesions may require open surgery.
Apical teat obstructions
Fibrosis and stenosis of streak canal due to chronic inflammation that may be associated with subclinical mastitis.
Use McLean’s knife to open teat end using cruciate incisions. Risk of stenosis.
Teat lacerations
Initial assessment to determine whether there is involvement of the teat canal is vital.
Deep wounds into teat canal can result in sinus formation and their repair is essential.
Superficial lacerations and deeper lacerations not involving the teat canal should be cleaned, debrided and skin sutures placed where necessary using fine metric suture material in a vertical mattress pattern.
Between milkings, the lesions should be protected by a teat bandage.
Lacerations into the teat canal should be repaired in 3 layers:
- mucosal lining,
- submucosal layer
- skin,
using a round bodied needle and fine suture material in a simple interrupted or continuous pattern.
Teat fistula
These are usually congenital flaps or secondary to trauma.
Determine whether there is an effect on normal teat drainage and leave alone, or trim and suture as necessary during the dry period.
Teat amputation
Sometimes indicated in cases of severe trauma or gangrenous mastitis.
Ligate above teat with rubber tourniquet, trim out milk sinus with scissors, close with three suture layers (mucosa, muscle, skin) using simple interrupted pattern with fine suture material.
If damage is severe the devitalised tissue can just be trimmed or crushed with a Burdizzo and then removed with scissors.
In cases of mastitis, particularly summer mastitis, the teat cistern should be left open to allow drainage.
Post operative care of teat surgery
Intra-mammary antibiotics (milking cow), teat cannula to allow milk let-down (self-retaining) for about 1 week.
Suture removal if indicated.
Indications for supernumary teat removal
Supernumary teats can interfere with milking and are associated with mastitis
Ideally removed in first month of life
Restrain and anaesthesia for supernumery teat removal
Young animals in dorsal recumbency
Standing in older animals
Anaesthetic must be used in cattle over 3 months
Surgical technique for supernumery teat removal
Isolated teats removed with burdizzo and sharp scissors
Attached teats may share common teat cistern so will need to be sutured
Amputation of the udder or parts of the udder
Amputation is not recommended because of the tendency for marked haemorrhage,
shock, and death, especially in lactating animals.
Indications for tail amputation
Injury to the tail, usually traumatic in origin. More commonly occurs in cattle, due to widespread tail docking of sheep
Restraint and anaesthesia for tail amputation
Standing using caudal epidural.
Surgical technique of tail amputation
The site is clipped and scrubbed.
On the healthy skin margin, cranial to the injury a V-shape full thickness skin incision is made on dorsal and ventral aspect of tail with tip pointing caudally.
The skin and soft tissue is undermined down to bone, trying to preserve as much of the soft tissue as possible with the skin.
Continue this proximally to the top of the V in the skin.
Cut through the bone (using suitable instrument to prevent fragmentation) or disarticulate bones at the level of the top of the V (cranially).
Close the soft tissue over the exposed bone margin using absorbable suture material.
Close the skin symmetrically.
There is no need to apply any form of dressing over the site.
To prevent haemorrhage an assistant holding the tail should put pressure on the tail vein until the skin incision is closed. Alternatively, a tourniquet can be used until the procedure is completed.
Indication for amputation of urethral appendage
In small ruminants where urolithiasis is suspected or diagnosed, the urethral (vermiform) appendage should be surgical removed in all cases.
This is often the site of blockage in these species as it is a narrow part of the male urinary tubular system.
Surgical procedure of amputation of the urethral appendage
In entire male animals the penis can exteriorised, and the urethral appendage identified and incised at the tip of the penis at an angle to create the greatest possible opening.
In castrated males, especially those castrated before puberty the penis can be difficult to exteriorise due to preputial adhesions, so it may be necessary to make an incision into the prepuce to get access to the penis to remove the urethral appendage as described earlier.
The skin is then sutured following this.
Indication for urethrostomy
Salvage procedure for the treatment of urolithiasis in fattening cattle and sheep.
Unsuitable procedure for retaining function in breeding animals.
Restrain and anaesthesia for urethrostomy
Sedation and caudal epidural in the standing animal is recommended.
High perineal urethrostomy technique
An incision is made high on the perineal midline.
The ventral commissure of this incision will be at the level of the sigmoid flexure.
An advantage of a high incision is that it allows the penis to be directed so that urine is expelled caudally and away from the inner aspects of the legs, which prevents urine scald of the rear limbs.
The subcutaneous tissue on the midline is bluntly dissected until the penis is identified.
The penis is isolated from the surrounding tissue, and a loop of the penis at the level of or just below the ischium is exposed.
The urethra starts to get wider at this point and is less likely to obstruct.
The loop of penis is anchored with heavy non-absorbable suture material, avoiding obstructing the urethra.
An incision is made into the urethra. A urethral catheter makes the urethra easier to identify. The incision should be at least two times the final opening as it is common to get 50% reduction in the size of the opening over time.
The mucosa of the urethra is sutured to the skin with absorbable suture material.
Haemorrhage from the corpus cavernosum is common and must be controlled.
Technique for low perineal urethrostomy
An incision is made low in the perineal midline just ventral to the sigmoid flexure and caudal and dorsal to the base of the scrotum.
The advantage of the low incision is greater accessibility to the penis and urethra.
The subcutaneous tissue on the midline is bluntly dissected until the penis is identified, differentiating between the penis and the paired retractor penis muscles.
The penis is isolated from the surrounding tissue.
Traction is applied caudally to straighten the flexure and expose a loop of the penis through the skin incision.
After the loop of the penis is exposed there are three options.
- Transection of the exposed penile loop, creating a 2-3cm stump with the proximal end of the penis. The dorsal artery and vein of the penis are ligated. The stump the penis is attached to the skin with 1-2 cm of penis exposed depending on size and species of animal. The urethra of the exposed penile stump may be split and its edges sutured in a flared position to enhance urine flow and to reduce the potential for urethral stricture.
- Traction on the ventral (distal) part of the exposed penis until the preputial attachment is ruptured and the entire distal penis can be extended backward through the perineal skin incision. The exposed penis is incised to create a 2-3 cm stump with the proximal end. The penile stump is then handled as described above.
- Urethostomy without penile transection as described in the high perineal urethostomy
Post operative care of urethrostomy
Systemic antibiotics if necessary
Observe the patient for passage of urine.
Send the animal for slaughter at the earliest opportunity.
Urolithiasis sequelae such as chronic cystitis is common.
Indication for tube cystostomy
A temporary procedure to establish urine flow while allowing a urethral obstruction and bladder rupture to be repaired and resolved.
The method allow urine to escape whilst uroliths can be passed or dissolved using dietary manipulation.
It is often used to maintain function of breeding animals and for companion farm animals, i.e., pet sheep and goats.
Likely to need hospital facilities due to the aftercare necessary after this procedure.
Restraint and anaesthesia for tube cystostomy
Dorsal recumbency with hind quarters elevated slightly to force the intestines cranially and away from the urinary bladder.
General anaesthesia is preferred.
Sedation followed by local anaesthesia infiltration of surgical site is also acceptable.
Surgical technique of tube cystostomy
The hair on the ventral abdominal wall from the pubis to the umbilicus is clipped.
The paramedian site is prepared for sterile surgery.
An 8-10cm paramedian incision is made on either the right or the left side.
The abdominal wall is incised, and the peritoneal cavity is opened carefully.
The urinary bladder is grasped and exposed through the abdominal incision and examined for tears and necrosis.
A stab incision is made into the ventrocranial urinary bladder.
A foley catheter is placed through the incision into the urinary bladder and the balloon is inflated.
If this does not feel secure, then a purse-string suture may be placed around the catheter and then anchored to the bladder.
The distal end of the catheter is passed through the abdominal wall lateral to the laparotomy incision.
Separate incisions are recommended so that the catheter will not delay healing of the laparotomy incision.
An adequate length of the catheter is left in the abdominal cavity to allow for dilatation, movement, and any other tension placed on the catheter and urinary bladder.
The catheter is anchored to the abdominal wall (at the point of exposure) with a simple suture of synthetic non-absorbable material.
The laparotomy wound is closed.
