Amputations Flashcards
what are the 2 MAJOR general indications for amputation?
- pain relief
- avoid self-trauma
what are more specific indications for amputation?
- neoplasia (osteosarc, chrondrosarc, soft tissue sarc, etc.)
- severe trauma
- peripheral nerve problems leading to non-functional limb
- compromised vascular supply
- intractable infection
- severe disability
What is involved in the “pre-operative” evaluation prior to an amputation?
- is an amputation appropriate (communicate with o the reason for amputating, prognosis, etc.)
- is the animal a suitable candidate (pre-op CBC/Chem/UA/Blood Type; xrays of the lesion; diagnosis of the lesion; stage if neoplasia; and work-up any comorbidities)
What are radiographic signs of an aggressive bony lesions?
- osteolysis (cortical, trabecular)
- periosteal reaction (long transition zone)
- soft tissue swelling (ext. of osteogenesis into soft tissue = OSA)
- pathological fractures
how much cortical bone loss needs to be present to see lysis on a radiograph?
40%
what is the best way to get a definitive diagnosis of a bony lesion?
bone biopsy
you can try FNA + cytology first, but biopsy is 80-90% accurate.
Where should you take a bone biopsy from in regard to the bony lesion?
MIDDLE of the lesion!!!!
what is the MOST common primary bone tumor in dogs?
osteosarcoma
esp in older, large/giant breeds
its rare in cats, but is still the most common primary brain tumor for them.
T/F: osteosarcomas are highly malignant in dogs and can be located at any bone site
true!
distal radius and proximal humerus are most common.
what is the most common age for osteosarcoma to appear in dogs?
8-9 years old.
what is MST for osteosarcoma in DOGS with amputation alone versus with amputation + chemo?
amp alone = 3-5 months
amp + chemo = 8-14 months
what is MST for osteosarcoma in CATS with amputation alone versus with amputation + chemo?
amp alone = 1.5-5 yr
chemo is up for debate.
what are the 5 general principles of amputation?
- remove the entire limb (Excess bone length creates extra weight and can cause pressure sores)
- gentle tissue handling
- adequate hemostasis
- analgesia
- thorough wound closure (tension free and eliminated dead space)
T/F: you should only transect the intrinsic muscles during an amputation
false – only extrinsic
if you transect the intrinsic muscles, it prolongs surgery time and increases morbidity.
what is the origin and insertion of the triceps?
origin: caudodistal scapula and medial/lat/caud proximal humerus
insertion: olecranon
Which of the following statements is FALSE about intraoperative technique for an amputation?
A. ligate the artery and the vein separately.
B. double ligate the major vessels
C. always ligate artery first
D. ligate with silk or long lasting absorbable (PDS, Maxon)
C. always ligate artery first
doesnt matter if you ligate artery or vein first.
artery 1st –> prevents loss/pooling of blood in limb
vein 1st –> limit metastatic spread
the femoral artery is the main supply to the hindlimb, what is the femoral artery a continuation of?
external iliac artery
The axillary artery is the main supply of the forelimb, what is the axillary artery a continuation of?
the subclavian artery which is a huge branch directly off of the aorta
what is the difference between electrosurgery and electrocautery?
electrosurgery is an electric current from an instrument moving through tissues. this causes heat, protein denaturation, and tissue dehydration
(good hemostasis, quicker, and decreased pain; buuut increases inflammation and decreases wound healing)
electrocautery does NOT pass a current through the tissues; it transfers energy in the form of heat.
T/F: you do not need a grounding plate when using a monopolar electrosurgery unit
false – plates are required for this type.
it is the bipolar type that does not require plates.
what is different about the Ligasure from monopolar devices?
Ligasure is a bipolar vessel sealing device that can ligate vessels up to 7 mm, whereas monopolar can only ligate up to 2 mm.
When is the appropriate time to provide local analgesia to amputation patients during surgery?
inject the nerves with bupivacaine PRIOR to cutting them
(remember to aspirate first)
what is the onset and duration of bupivacaine?
onset = 5 min
duration = 4-6 hrs
what are the 2 techniques for amputating the thoracic limb?
bonus: which is better?
- removal of the scapula
- disarticulation of the shoulder joint
better one: remove the scapula
disarticulation leaves too much bone behind, muscle atrophy and pressure sores.
what are the 8 extrinsic muscles of the thoracic limb?
- trapezius (cervical and thoracic parts)
- omotransversarius
- cleidobrachialis
- superficial pectoral
- deep pectoral
- rhomboideus
- serratus ventralis
- latissimus dorsi
what are 7 nerves of the brachial plexus that need to be transected in a thoracic limb amputation?
- suprascapular
- subscapular
- musculocutaneous
- axillary
- radial
- median
- ulnar
what are the 3 major vessels of the thoracic limb that need to be ligated during amputation?
- axillary artery and vein
- lateral thoracic artery, vein, nerve
- thoracodorsal artery, vein, nerve
What are the 3 goals of closure in an amputation?
- appose the muscle bellies to provide protection for vascular pedicle and transected nerve endings
- eliminate dead space
- tension free skin apposition
where will you find the axillary artery and vein in relation to the scapula?
ventromedial
what are the 2 amputation techniques for the pelvic limb?
bonus: which is the preferred technique
- disarticulation of the coxofemoral joint
- mid-femoral osteotomy
preffered: disarticulation (no extra weight of stump, no pressure sores, no muscle atrophy, but does require more time and more dissection)
Describe the skin incision for the disarticulation technique for pelvic limb amputation
from flank to ischiatic tuberosity
on lateral side – semicircular at the level of the mid-femur;
on medial side – more inguinal
what are the 3 major vessels of the pelvic limb to ligate prior to amputation?
- femoral artery and vein (in femoral triangle; ligate it proximal to the superficial circumflex iliac and lateral circumflex femoral branches)
- medial circumflex femoral artery and vein (in femoral triangle)
- caudal gluteal artery and vein (deep to gluteal muscles)
what 3 muscles make up the femoral triangle?
- sartorius (caudal belly)
- pectineus
- vastus medialis
what are the 17 extrinsic muscles that need to be transected in the pelvic limb amputation?
- sartorius (cr and cau bellies)
- gracilis
- adductor (magnus and brevis)
- pectineus
- rectus femoris
- tensor fascia lata
- biceps femoris
- superficial gluteal
- middle gluteal
- deep gluteal
- abductor cruris caudalis
- semitendinosus
- semimembranosus
- gemellis
- internal obturator
- external obturator
- iliopsoas
what are the 3 nerves that need to be injected with bupivacaine and transected in the pelvic limb?
- sciatic (deep to biceps femoris)
- femoral (cranial)
- saphenous (lat or cra to femoral artery in femoral triangle)
T/F: you have to incise the joint capsule of the pelvic limb for amputation
true the articularis coxae
you may need to also transect the ligament of the head of the femur
what are the 3 tools you can use to perform the mid-femoral osteotomy?
- oscillating saw
- gigli wire
- osteotome
what 2 things do you need to do prior to every closure of a limb amputation?
- lavage and inspect the wound bed for adeq hemostasis
- oncologic – check lymph nodes or collect (some may come with the limb); and change gloves and instruments!!!
T/F: the incision line for a mid-femoral osteotomy needs to be medial to the stump
true to avoid pressure and for cosmetic purposes.
which lymph node is removed with pelvic limb amputation?
popliteal
what would you recommend for post-op management of a patient who just had a limb amputation?
- bandage/stockinette
- leash walk ONLY (2 weeks)
- ucath/bladder expression if patient cannot ambulate
- cold compress 24-72 hr (vasoconstriction, dec nerve conduction, and dec muscle spasms)
- warm compress >72 hr (vasodilation)
- analgesia (injectable NSAID, gabapentin when awake, other opioids – pure mu agonists, ketamine, lidocaine)
what are the 9 complications of a limb amputation?
- hemorrhage/hematoma
- seroma
- dehiscence
- infection
- recurrence of neoplasia
- neuroma
- cervical disc herniation
- phantom pain
- increased risk of injury/dz to other limb
what is generally the outcome/prognosis of a limb amputation?
good to excellent function
high owner satisfaction
can lead to obesity, gait changes, adaptation and balance challenges, behavior changes, and degenerative joint disease in other limb
T/F: the risk of developing degenerative joint disease in the contralateral limb after amputation is a contraindication for the procedure
false – its a risk, but it is not a contraindication
what are 5 alternatives to amputation?
- pain meds (limited efficacy)
- radiation therapy
- partial amputation
- limb spare
- cementoplasty
what are indications for digit amputation?
- neoplasia
- chronic infection
- osteomyelitis
- severe trauma
T/F: the outcome of digit amputation is good to excellent function even if you remove digits 3 and 4 (weight bearing)
true
what are the indications for tail amputation?
- trauma
- paralysis
- neoplasia
- tail fold pyoderma
- perianal fistulas
- lateral caudal skin flap
where do you make your incision for a tail amputation in reference to the site of disarticulation?
make a circumferential incision DISTAL to the site of disarticulation
