59 - Lower Extremity Amputation

Question 1

Indications for lower extremity amputation

Answer 1

• Acute infection
• Chronic infection
• Ischemic limb
• Gangrene
• Charcot deformity
• Trauma
• Tumors
• Congenital Abnormalities

Question 2

Reasons for distal limb salvage

Answer 2

• Superior Function (transmet amputation is much more functional than BKA)
• Better Cosmesis
• Enhance Lifestyle
• Lower Energy Consumption
• Increased Sensory Input
• Better Weight-bearing Surface
• Less Distortion of Body Image

Question 3

Considerations for successful limb salvage

Answer 3

• 1 = Ensure good blood flow
• 2 = Control infection
• 3 = Aim for good biomechanical result
• 4 = Create a stable soft tissue envelope***
  o We typically use some of the plantar soft tissue structures – very protective
  o Not only so the patient can heal, but also so they can protect it

Question 4

Successful amputations

Answer 4

• “Remove all necrotic, painful, or infected tissue.”
• “Must be able to fit amputation stump with a functional and easily applied prosthesis.”
• “Blood supply at the level of the proposed amputation must be sufficient to allow primary skin healing.”

Question 5

Major factors to consider for amputation level - VASCULAR status

Answer 5

o Determining the level of adequate blood flow can help predict success of healing
o Not meeting criteria is not always considered a contraindication to performing amputation at a certain level

Question 6

Prediction of healing based on vascular status

Answer 6

• Still speculative and work continues (“I have cut many things that have bled poorly and healed well, and I have cut many thing that have bled well and healed poorly”)
• Doppler Ultrasound
• Segmental Blood Pressure
• Ankle Brachial Index
• Toe Blood Pressure
• Plethysmography
• Transcutaneous Oxygen Pressure
• Spy technology – intra operative evaluation with dye and imaging (Emerging technology)

Question 7

Timing of surgery after vascular intervention

Answer 7

STUDY – Attinger et al recommended that you do surgery…
o 4 to 10 days after a bypass vascular procedure
o 10 to 30 days after an angioplasty vascular rocedure

Personal experience
o My experience with local vascular surgeons and interventionalists
o Definitive procedure as quickly as possible
o Typically can keep patients vascular medications: Plavix, etc.
o If the patient has an INR of 3 or above, they are not a candidate for surgery due to too much bleeding, but if it is a minor procedure, you will likely be able to control the bleeding with an INR of 2 – It doesn’t always need to be under 1/5 in order to operate

Question 8

Angiosomes and healing potential

Answer 8

• Angiosomes: composite vascular territories providing
  blood supply to skin, nerves, muscle, tendon, and bone
• The angiosome concept was derived from plastic
  surgery to evaluate healing potential of flaps.
• Entire body is divided into 40 angiosomes.

Question 9

Angiosomes in the foot

Answer 9

The foot is divided into 6 angiosomes total
o The posterior tibial artery feeds 3 angiosomes
o The anterior tibial artery feeds 1 angiosome
o The peroneal artery feeds 2 angiosomes

Question 10

Posterior tibial artery

Answer 10

• The posterior tibial artery gives rise to a calcaneal branch, which supplies the medial ankle and lateral plantar heel, a medial branch that feeds the medial plantar instep, and a lateral branch that supplies the lateral forefoot, plantar midfoot, and entire plantar forefoot

Question 11

Anterior tibial artery

Answer 11

• The anterior tibial artery continues on to the dorsum of the foot, as the dorsalis pedis

Question 12

Peroneal artery

Answer 12

• The peroneal artery supplies the lateral ankle and plantar heel via the calcaneal branch and the anterior upper ankle via an anterior branch

Question 13

Major factors to consider for amputation level

Answer 13

• Rehabilitation Potential
• Ambulatory Status
• Medical considerations

Question 14

Rehabilitation Potential

Answer 14

o Ambulatory Status at time of presentation
o Motivation
o Family /Social Support
o Other comorbidities – cardiac, pulmonary, neurological, musculoskeletal

Question 15

Ambulatory Status

Answer 15

o If not ambulatory, BKA or AKA may be better level

o Even if patient is not ambulatory, maintaining limb can be advantageous for transfers

Question 16

Medical considerations

Answer 16

o NOTE: In planning appropriate consultation for perioperative medical care, the podiatric surgeon should be aware of the evaluation of physical status completed by the anesthesiologist before surgery – Consider ability to undergo ANESTHESIA***
o The surgeon should ensure that appropriate medical consultation, clearance, and follow-up have been obtained to provide for the perioperative medical care of a diabetic patient who will undergo surgery for an infected foot

Question 17

Anesthesia classes of patients

Answer 17

• Class 1
• Class 2
• Class 3
• Class 4
• Class 5

Question 18

Class 1 anesthesia patient

Answer 18

Class 1 patients have no medical problems, other than the pathologic condition associated with the surgery, no diabetic patient will fit this category

Question 19

Class 2 anesthesia patient

Answer 19

Class 2 patients have a stable, chronic medical problem that is well controlled such as stable diabetes

Question 20

Class 3 anesthesia patient

Answer 20

Class 3 patients are more seriously ill, with unstable medical problems, and are more likely to need intensive, or at least close, medical supervision in the perioperative period

Question 21

Class 4 anesthesia patient

Answer 21

Class 4 patients are very seriously ill, perhaps at risk for septic shock, or other major cardiovascular complications and definitely require intensive perioperative care

Question 22

Class 5 anesthesia patient

Answer 22

Class 5 patients are not expected to survive surgery or the perioperative period

Question 23

Rehabilitation team model for lower extremity amputation

Answer 23

• Surgeon
• PT/OT
• Family support, hospital nurses and paramedical personnel
• Referring physician, community resources, prosthetist
• Patient needs to do the things that they are responsible for – You can do as many consults as you want, but if the patient is not responsible, there will be issues

Question 24

Amputation levels

Answer 24

• Toes (partial, complete)
• Partial rays (1st ray, middle ray, 5th ray)
• Transmetatarsal
• Lisfranc’s (NOT preferred – do a transmetatarsal amputation instead)
• Hindfoot (Choparts, Boyds and Pirogoff, Symes)
• Calcanectomy
• Below knee (BKA)
• Above knee (AKA)

Question 25

Lisfranc’s amputation = BAD PROCEDURE

Answer 25

- Poor outcomes compared to a transmetatarsal amputation - This is because the tendon attachments for supination and pronation are all within the tarsal-metatarsal joints (1st and 5th metatarsal) - If you can do a transmetatarsal, definitely do that instead - If you can’t do a transmetatarsal procedure, go more proximal to a hindfoot procedure such as a Choparts amputation

Question 26

Toe amputation

Answer 26

- Toe amputation is frequently performed through the base of the proximal phalanx - This is left in place to maintain intrinsic muscle stability around the metatarsal phalangeal joint - Resection at the proximal metaphysis allows for closure over raw cancellous bone, which is an area that is better vascularized than the cartilage of the metatarsal head - Skin incisions are made with medial and lateral flaps fashioned around the base of the digit

Question 27

Ray resections

Answer 27

- Ray section is defined as amputation of a digit and most, or all, of its associated metatarsal - This is an excellent procedure for drainage of an acute infection - It is usually performed in the presence of either abscess or osteomyelitis of a toe and its MPJ - Extensive necrosis of skin, soft tissue, or bone in the involved digit may necessitate ray resection to obtain adequate viable skin for closure - If you probe the bone and it feels hard, that is a good level to amputate - If you probe the bone and it feels soft, you need to continue amputating more proximal

Question 28

CASE STUDY 1

Answer 28

- 63 year old male s/p partial ray resection of the left 2nd - S/P angiogram w/ stent - Recent hallux amputation with additional partial 3rd ray resection

Question 29

CASE STUDY 2

Answer 29

- 59 year old male with a history of psoriasis, and s/p kidney transplant - Developed a verruca of the 4th digit. The toe was amputated, but patient retained the verruca - 2 months s/p biopsy and surgical treatment

Question 30

Transmetatarsal amputation indications

Answer 30

o Gangrene of one or more toes, provided the gangrene has stabilized and does not involve the dorsal or plantar aspect of the foot o Stabilized infection or open wound of the distal portion of the foot o An open infected lesion in a neuropathic foot o Extension of an infectious process to the web space or plantar aspect of the foot is an indication for an open transmetatarsal amputation. (This may be closed at a later time or allowed to heal by second intention.)

Question 31

Details of transmetatarsal amputation

Answer 31

- This amputation maybe performed at any level of the metatarsals, provided the insertion of the tibialis anterior tendon is preserved - Preservation of the tendon cannot be overemphasized as loss of function will result in an equinus deformity - With a transmetatarsal amputation, you want to do a gastroc recession or tendo calcaneus lengthening, reducing the risk for callus at the stump site

Question 32

Hindfoot amputations

Answer 32

- Choparts = Disarticulation at Talonavicular and calcaneal cuboid joint - Boyd – tibial – calcaneal fusion or Modified Boyd’s – utilize talus as interposition bone graft if viable - Pirogoff – tibial – calcaneal fusion = Calcaneus is positioned vertical to help alleviate limb length discrepancy - Symes – Full ankle disarticulation = Significant limb length discrepancy will result

Question 33

Surgical considerations

Answer 33

- Check Hemaglobin and Hematocrit - Many patients have had a LE bypass or stent, so general consensus is not to utilize tourniquet - Expect blood loss, take your time but have at least 2 units of blood available at time of surgery

Question 34

Stabilization of hindfoot

Answer 34

- Need to stabilize hindfoot fusions in most cases for long term success - Steinman pin or K-wires - Screws, external fixation or IM Rod

Question 35

Choparts amputation

Answer 35

- Diabetes Mellitus, Peripheral Neuropathy, multiple amputations Left foot - Chronic ulcers, osteomyelitis - Does not result in a limb length disparity which is an advantage of this procedure

Question 36

STUDY – Boyd

Answer 36

- Boyd, H. R., Amputation of the Foot, with Calcaneotibial Arthrodesis - Developed the amputation for the patient who cannot afford an artificial leg, or for the laborer to give an excellent WB stump and relieve the patient of having to use an artificial limb Advantages o A natural, painless stump is provided o Operation is more advantageous from an anatomical and physiological standpoint over other amputations through the region of the ankle or tarsus o Recognized problems in other amputations

Question 37

Modified Boyd’s

Answer 37

- Kornah, 1996 | - Utilize talus as graft to help fill defect at fusion site

Question 38

CASE STUDY 3

Answer 38

- 55 year old diabetic male - ESRD – kidney transplant - PVD – Right LE bypass - Left below knee amputation - Retinopathy - Charcot arthropathy with 5th ray amputation - Neuropathic lateral ankle ulcer - Unstable, un-braceable ankle varus deformity

Question 39

Syme’s amputation

Answer 39

- Disarticulation at ankle – outside of scope of practice in most states - Advocated for alternative to BKA, but may be better off doing a BKA o Full length extremity that can be used in emergency ambulation o Boyd Amputation o Symes with tibialcalcaneal fusion o Allows for more length of limb - Single Stage procedure or double Stage procedure - When done, 2nd stage is to remove malleoli and to remodel stump for prosthesis - Controversy surrounds the stability of the amputation and difficulty related to prosthetic construction

Question 40

Calcanectomy

Answer 40

- Partial or complete removal of calcaneus - Advantageous for large heel ulcers with calcaneal osteomyelitis and a stable midfoot and forefoot - Patients are typically able to ambulate well with or without an assistive device (ankle foot orthosis –AFO) - Good alternative to BKA or AKA

Question 41

CASE STUDY 4 – Partial calcanectomy

Answer 41

- 65 year old female presents with a necrotic wound of the left heal. - Patient states of 2 ½ weeks duration. - PMH: IDDM, Venous stasis, lymph edema - 1 month s/p debridement of bone and soft tissue, with wound vac assisted closure - 4 month s/p procedure wound is healed. - Patient currently ambulates with an AFO and a walker