Ch 65 Amputations

Question 1

Indications to perform an amputation include

contraindications (2)

Answer 1

(1) soft tissue or bone neoplasia
(2) severe trauma to the bones, joints, or soft tissues of a limb
(3) peripheral nerve problems (e.g., neoplasia or trauma leading to avulsion)
(4) ischemic necrosis
(5) intractable orthopedic or soft tissue infection
(6) severe disability (osteoarthritis or congenital deformity)

Contraindications:
- severe orthopedic or neurologic disease affecting the other limbs
- extreme obesity

Question 2

pre-op consdierations:

Answer 2

• The other limbs are assessed orthopedically and neurologically.
• trial temporary sling
• omplete blood count (CBC), chemistry panel, and urinalysis
• Educating owners before the surgery

Question 3

What local anaesthetics can be used for blocking nerves during amputation?
What is the maximum dose?

Answer 3

0.5% bupivicaine or 0.5% ropivicaine
Maximum 2mg/kg

Question 4

General Principles and Considerations

Answer 4

• Leaving excessive length to the limb without use of a prosthesis can lead to pressure sores and results in an unnecessary mass
• only extrinsic muscles of the limb need to be transected
• Paralysis helps minimize muscle fasciculation during transection
• Major arteries and veins are divided and ligated individually to prevent the formation of arteriovenous fistula
• arteries are double ligated. When vessels are large, the second ligature can be a transfixation ligature for added security
• been suggested to ligate the vein first in order to limit the possibility of metastasis during surgical manipulation (contraversial)
• Electrosurgery is also helpful in performing midbelly myotomies
• wound soaker catheters can be placed

Question 5

What are the options for thoracic limb amputation?

Answer 5

1. Removal of the scapula
2. Disarticulation (cons: bony prominences of the scapula, particularly the acromion, to create pressure sores)

Question 6

What vessels and nerves are encountered during amputation by removal of the scapula?

Answer 6

• Omobrachial and cephalic vein
• Branches of superficial cervical artery inclusing suprascapular artery
• Lateral thoracic artery, vein and nerve
• Thoracodorsal artery, vein and nerve
• Brachial plexus
• Axillary artery and vein
• External thoracic artery

Question 7

Where can the superficial cervical and axillary LNs be located during forelimb amuptation?

Answer 7

• Superficial cervical LN: Located along prescapular branch of superficial cervical artery at its cranial aspect, deep to brachiocephalicus muscle
• Axillary LN: Located along lateral thoracic artery, caudal to axillary vein, medial to latissimus dorsi and deep pectoral muscles

Question 8

Answer 8

• axillary artery and vein lie ventromedial to the caudal portion of the brachial plexus
• closre: trapezius, the omotransversarius, and brachiocephalicus muscles are sutured to the latissimus dorsi muscle. The pectoral muscles
• drain usually not required

Question 9

List the options for pelvic limb amputation (4)

Answer 9

Disarticulation
Osteotomy of the femur (mid-femoral)
En bloc with acetabulectomy
Em bloch with hemipelvectomy

Question 10

Why does osteosarcoma more commonly cross the hip joint?

Answer 10

Ligament of the head of the femur is though to act as a bridge

Question 11

What blood vessels and nerves are encountered during a pelvic limb amputation via disarticulation?

Answer 11

Femoral artery and vein
Saphenous nerve (cranial/lateral to femoral artery)
Medial circumflex femoral artery (caudally in femoral triangle)
Superficial circumflex iliac artery and lateral circumflex femoral artery and vein may need to be ligated if femoral artery and vein are ligated distal to these branches
Caudal gluteal artery and vein
Sciatic nerve
Femoral nerve

Question 12

mid-femur

Answer 12

Question 13

disarticulation

Answer 13

• medial aspect to expose the femoral triangle
• caudal edge of the sartorius muscle and cranial to the pectineus muscle. The saphenous nerve is found
• sartorius, cranial and caudal parts, gracilis, and, at a deeper level, adductor magnus et brevis
• Moving cranially, the rectus femoris muscle can be transected midbelly
• laterally:tensor fasciae latae muscle, cranially, and biceps femoris muscle
• superficial, middle, and deep gluteal muscles
• caudal gluteal artery and vein and also the sciatic nerve
• internal obturator, gemelli muscles, the external obturator muscle
• branch of the lateral circumflex femoral artery
• caudal aspect of the limb, the abductor cruris caudalis, semitendinosus, and semimembranosus muscles
• cranial: liopsoas muscle is identified and the femoral nerve

Question 14

What osteotomies are required for an acetabulectomy?

Answer 14

Ilial body, ischium and pubis

Question 15

outcome

Answer 15

• Studies have reported that virtually all owners are very satisfied with the function of their pet after amputation
• Obesity appears to have a negative impact on mobility and stamina of the canine amputee
• he vertebral column, carpus, and ipsilateral hip and stifle joints had significant biomechanical changes after amputation of a thoracic limb.
• Behavioral changes are uncommon after an amputation, but such changes have been reported in 9% to 32% of canine amputees.
• mild and even moderate degree of degenerative joint disease in the remaining limbs is not a contraindication to amputation.
• Double amputation (one thoracic limb and one pelvic limb) is possible in dogs

Question 16

complications (7)

Answer 16

• hemorrhage,
• seroma
• dehiscence,
• infection (13% of dogs and 3.6% of cats)

pain post amputation:
- neuroma formation,
- cervical disc herniation
- phantom pain

Question 17

What alteration is recommended if performing a THR in a dog with a contralateral pelvic limb amputation?

Answer 17

Recommended to place the acetabular cup in a more closed position to decreases the risk of luxation (4/9 amputees had post-THR luxation in one study)

Question 18

List the options for prostheses after a partial limb amputation (2)

Answer 18

• Intraosseous (intraosseous transcutaneous amputation prosthesis ITAP)
• Socket prosthesis (slipped on and off the limb and fits over the stump)

Question 19

How much of the limb must be remaining for a socket prosthesis?

Answer 19

At least 30% of the radius/ulna or tib/fib

Question 20

Reported complications of intraosseous transcutaneous amputation prostheses are

Answer 20

aseptic loosening
fracture of the prosthesis

Question 21

What is a partial foot amputation?

Answer 21

Amputation of two adjacent digits en bloc, with or without the corresponding MC/MT bones

• Function following partial foot amputation is good to excellent, even if 3 and 4

Question 22

How does the vasculature of the tail differ in the cranial tail compared to the tip of the tail?

Answer 22

• Cranial 1/3: typically 7 longitudinal arterial trunks
• Only the 2 lateral caudal arteries and the median caudal artery reach the tip

Question 23

high tail amputation

Answer 23

• at the level of the second or third caudal vertebra,
• tail fold pyoderma, paralysis
• The coccygeal and levator ani muscles are severed at their attachments to the caudal vertebrae.
• Blunt dissection break down the fascial attachment between the ventral tail and the rectum.
• Care is taken to ensure protection of the rectum,
• cut surface of the bone can be controlled with sterile bone wax

Question 24

Comparison of bupivacaine liposome injectable solution
and fentanyl for postoperative analgesia in dogs undergoing
limb amputation
Paul 2024

Answer 24

Randomized, double-blind, prospective, controlled, intent-totreat,
clinical noninferiority trial.
Animals: Forty client-owned dogs.

BLIS provides equivalent analgesia, this may allow for decreased reliance on opioids in the immediate postoperative period.

Question 25

Incidence of and risk factors for surgical site infection
following canine limb amputation
Billas 2022

Answer 25

Retrospective, multicenter study.
Animals: Dogs (n = 248).
The incidence of SSI was 12.5% for all procedures and 10.9% for clean
procedures.

Use of bipolar vessel sealing devices for muscle transection
increased the odds of developing an SSI whereas use of electrosurgery
and/or sharp transection did not. Dogs with surgical sites that were other than
clean, or with bacterial infection and/or traumatic injury were also at
increased odds of SSI.

Question 26

Subcutaneous vascular access ports (SVAPs) are surgically
implanted devices connected to a catheter within a
central vein, allowing long-term access to the vascular
system. In veterinary medicine, they are used to administer
chemotherapy and anesthetic agents

Answer 26

The axillary or femoral/external iliac veins offer
alternative sites for placement of SVAP in dogs undergoing limb amputation.

Question 27

Modified hemipelvectomy techniques in dogs and cats appear well tolerated with good functional outcomes
Griffin 2023

Answer 27

23 client-owned animals (20 dogs and 3 cats
performed with partial sacrectomy and/or vertebrectomy in 11 dogs, excision crossing pelvic midline with concurrent limb amputation in 5 dogs and 2 cats, and closure without use of native muscle or mesh in 4 dogs and 1 cat.

partial sacrectomy/vertebrectomy (4/11) experienced postoperative mobility concerns. Major intra- or post-operative complications (grades 3 and 4) occurred in 2 dogs that underwent partial sacrectomy/vertebrectomy, and 1 of these animals experienced a complication that resulted in death.

The outcomes of these dogs and cats challenge several widely held notions, including tolerable proportion of sacrum that can be excised, potential for functional compromise with disruption of the contralateral pelvic structures when concurrent limb amputation is performed, and the requirement for reconstruction of the resulting hemipelvectomy abdominal defect with local muscular tissues or mesh.

Question 28

hemipelvilectomy
bray 2014

Answer 28

The modified technique
reported here allows muscles and related soft tissues of the
pelvis to be transected at their sites of origin or insertion, or to
be removed in toto without disruption. T

After wound lavage, the sartorius muscle ( ) can be
unwrapped from its moist swab and draped across the defect. It is
then sutured to the abdominal muscle

, but tumor‐free margins were
achieved in all animals that had the anatomic dissection
described in this report compared to rates of 25–50% recorded
with approaches made by others

incomplete resection margins
were reported after hemipelvectomy in almost a third of cases
(29 dogs, 4 cats) and local tumor recurrence developed in 13/83
(16%) dogs and 2/16 (12.5%) cats. The high rates of
incomplete resection for many tumors in our report

metastatic disease common cause of death after hemipelvectomy, occurring in
39/83 (47%) dogs and 2/16 (12.5%) cats.8
- Taken overall, only about 50% of dogs with malignant mesenchymal tumors (i.e.
hemangiosarcoma, osteosarcoma, chondrosarcoma, soft tissue
sarcoma) remained alive 1 year after surgery