Foot reconstruction, including ulcers

Question 1

what is the ABI?

Answer 1

• o ABI = comparison of systolic occlusion pressure of the brachial artery to the a) dorsalis pedis and b) posterior tibial occlusion pressure

o ≥ 1.0 = normal

o ≥ 0.7-1 = mild, RF mod, ± antiplatelet agent

o 0.5-0.7 = mod, as above + ref to vasc sx, ± imaging

o ≤0.50 = severe; as above + urgent ref to vasc sx

o ≤ 0.3 or ankle sBP <50mmHg = critical ischemia, urgent ref to vascular on-call

o extensive atherosclerosis leads to medial calcification and falsely elevated ABIs

Question 2

compare arterial, venous and diabetic ulcers

Answer 2

Arterial

Venous

Diabetic

Pathophysiology

Progressive atheroschlerosis

Valvular incompetence

Previous DVT / post-thrombotic syndrome

Neuropathy & autonomic dysfunction & micro/macrovascular

Risk factors

Age, DM, smoking

Obesity, VTE, varicosities

Occult trauma

Poorly fitting / inadequate foot-wear

Charcot changes

History - symptoms

Painful, pain w elevation

Claudication

Less painful, discomfort w/ dependence, as day progresses

Polyneuropathy

Location

Foot / shoe / lat malleolus

“Gaitor” esp med malleolus

Pressure areas

Appearance

Punched out, defined margins

Pale, dry

Shallow, irregular margins

Ruddy/fibrin/granulation, wet

Callous over undermined wound +/- penetration to bone

Charcot changes

Associated findings

Thin, cool, hairless

Diminished/absent pulses

Inverted champagne

Hemosiderin deposition

Signs of infection (cellulitis, purulence, wet/dry gangrene)

+/- vascular insufficiency

ABI, other Ix

Bedside Doppler

ABI +/- toe digital pressure

à ABI < 0.7 abn; < 0.5 ischemia; < 0.3 = critical

TcO2

Duplex Doppler best test

Usually normal

HbA1c

Still Doppler/vascular studies

Treatment Principles

Medical: Pentoxifylline, ASA

Vasc Sx assess if ABI < 0.7

Debridement unlikely to be of benefit if ABI < 0.7

Consider HBO consult

Leg elevation

Activity

Compression stockings (ABI > 0.8 for high graduated comp’n)

Sx tx of superficial veins

Glucose control

Podiatry: shoes, foot care, avoidance of trauma & pressure

Aggressive tx of infection (oral / IV abx) and surgical debridement if req’d

Question 3

what is phlegmasia cerulea dolens?

Answer 3

• Acute fulminating form of DVT commonly w/ trauma/cancer
• Massive increase in pressure in hours with massive edema (6-10L) –> art insuff –> agonizing pain
• Investigations – rule out compartment syndrome
• Treatment – elevation, heme/vasc consult urgently

Question 4

describe the pathophysiologic mechanisms of wounds/ulcers in DM

Answer 4

• Vascular:
• Occlusive macroangiopathy – usually tibial/peroneal
• Nonocclussive microangiopathy – changes in bld visc (HbA1c + RBC); thickened BM –> ↓WBC migration; ↓ cap vasodilation
• Polyneuropathy and microtrauma (primary mechanism)
• 2ary to elevated intraneural concentration of sorbital
• nerve swelling and compression
• decreased repair/regeneration of nerves
• altered vasoactive substances (NO)
• oxidative stress
• AGE - advanced glycosylated end-products - causes microvascular insult to nerves
• Hyperglycemia and decreased ability to fight infection / increased susceptibility to infection
• Decreased stem cells and stem cell pluripotency diminishes wound healing capability

Question 5

list options available to reconstruction of foot wounds

Answer 5

• secondary intention +/- w/ adjuncts like VAC, HBO
• STSG/FTSG with healthy wound bed, no tendon w/o paratenon, non-weight bearing
• local random flaps (V-Y, filet)
• pedicle regional flaps
• propellor flaps
• free flaps
• combination

Question 6

Options for achilles tendon, ankle, foot dorsum

Answer 6

• extensor digitorum brevis muscle flap
• lateral supramalleolar flap
• reverse sural artery fasciocutaneous flap (for ankle & achilles)
• propellor

Question 7

Options for plantar forefoot

Answer 7

• Neurovascular island flap from fibular side of great toe
• Toe fillet flap s/p ray amputation
• V-Y flap, opposing V-Y advancement flaps
• Utilizing viable plantar +/- dorsal +/- toe fillet flaps for transmetatarsal forefoot amputation

Question 8

Options for plantar mid-foot

Answer 8

o Local flaps: V-Y,ying-yang, O to T

o STSG to arch; thick STSG or FTSG of glaborous skin from arch to weight bearing surface and STSG to resurface arch

o Neurovascular island flaps with more proximal dissection of neurovascular bundle

• Midfoot amputation

Question 9

Options for plantar hindfoot

Answer 9

• abductor hallucus muscle flap (medial plantar artery)
• Reverse sural artery fasciocutaenous flap
• Medial plantar artery neurotized fasciocutaneous flap (from post-tib)
• Lateral calcaneal artery (terminal branch of peroneal a)
• Propellor
• Free flap

Question 10

when would you consider free flap for FOOT reconstruction?

Answer 10

• Large hindfoot wounds (>6 cm)
• defects in patients devoid of the posterior tibial vessels (from either trauma or disease)
• patients who have been revascularized to the distal anterior tibial/dorsalis pedis artery via bypass grafts
• consider thin/thick; functioning muscle