KEY NOTES CHAPTER 6: LOWER LIMB - Pressure Ulcers.

Question 0

What is the epidemiology of pressure ulcers?

Answer 0

• Develop in 3-14% of hospitalised patients.
• Associated with fivefold increased mortality in the elderly.

• Tend to occur in:
∘ The old
∘ The hospitalised
∘ The young neurologically impaired.

Question 1

Define pressure ulcer.

Answer 1

Definition: a localised injury to the skin and/or underlying tissue, usually over a
bony prominence, as a result of pressure or pressure in combination with shear.

The microclimate (moisture and temperature) also contributes.

Question 2

Where can pressure ulcers occur?

Answer 2

∘ Sacrum
∘ Heel
∘ Ischium
∘ Elbow
∘ Malleolus
∘ Trochanter
∘ Knee
∘ Scapula
∘ Occiput.
∘ With medical devices, e.g. nasogastric tubes, CPAP.

Question 3

What is the pathogenesis?

Answer 3

• Pressure ulcers are initiated by extrinsic factors and propagated by intrinsic factors.

Extrinsic factors

• Pressure
• Shear
• Friction

Intrinsic factors

• General
• Local

Question 4

How does pressure cause pressure ulcers?

Answer 4

• Prolonged pressure -> tissue ischaemia -> necrosis and ulceration.
• Low pressure over long time = high pressure over a short period.
• Necrosis first occurs in tissues closest to the bone, usually muscle. Skin necrosis occurs late.
∘ Results in a characteristic cone-shaped wound - degree of skin loss is the tip of the iceberg.

Question 5

What is shear and friction?

Answer 5

Shear
• Mechanical stress applied parallel to the skin’s surface.
∘ Skin moves in the opposite direction to bone.
• Less pressure is required to occlude blood vessels.

Friction
• Opposes movement of one surface against another.
• When a patient is dragged across a surface, or ill-fitting shoes.
• Loss of epidermis may initiate or accelerate pressure ulceration.

Question 6

What intrinsic factors propagate the development of pressure ulcers?

Answer 6

General
• Old age
• Immobility
• Acute illness or terminal illness
• Impaired nutrition or hydration
∘ Low lean body mass
∘ Anaemia
• Impaired perfusion
∘ Diabetes
∘ Smoking
∘ Peripheral vascular disease
∘ Use of vasopressors.

Local
• Local ischaemia or fibrosis
• Decreased sensation
• Loss of autonomic control
• Skin moisture
∘ Excessively dry or moist skin both contribute to pressure ulceration
∘ Urinary and faecal incontinence
• Infection.

Question 7

How do the European Pressure Ulcer Advisory Panel (EPUAP) and American National Pressure Ulcer Advisory Panel (NPUAP) categorise pressure ulcers?

Answer 7

Category I: Non-blanchable erythema
• Intact skin with non-blanchable redness of a localised area, usually over a bony prominence.
• Discolouration, warmth or induration may be indicators in individuals with dark skin.

Category II: Partial thickness
• Partial thickness loss of dermis presenting as a shallow open ulcer with a red pink wound
bed, without slough.

Category III: Full thickness skin loss
• Subcutaneous fat may be visible but bone, tendon or muscle are not exposed.

Category/Stage IV: Full thickness tissue loss
• Exposed bone, tendon or muscle. Slough or eschar may be present.

Question 8

How are patients risk assessed for pressure ulcers?

Answer 8

∘ Norton score (1962)
∘ Waterlow score (1985)
∘ Braden score (1987)

Question 9

Describe the Waterlow scoring system

Answer 9

• Updated in 2005 based on new research.
• Most widely used risk assessment tool in UK.
• Patients are scored on these factors:

∘ BMI
∘ Skin type and risk areas
∘ Sex and age
∘ Appetite and weight loss
∘ Continence
∘ Mobility
∘ Special risks
- Tissue malnutrition, neurological deficit, major surgery or trauma, medications.

• Scores 10+ - at risk
• Scores 15+ - high risk
• Scores 20+ - very high risk

Question 10

How are pressure ulcers prevented?

Answer 10

• Skin care (emollients, barrier areas, clean and dry skin regularly, remove particulate matter from beneath patient)
• Urinary or faecal diversion
• Nutrition
• Positioning (avoid bony prominences, pillows)
• Repositioning (bed bound 2hrly, seated every 15-30mins.)
• Pressure dispersion (alternating-pressure mattresses)
• Pressure awareness (patient and carer education)

Question 11

What is the treatment for pressure ulcers?

Answer 11

Non-operative
1 Optimise the patient
• Nutrition
• Comorbidities, e.g. diabetes or anaemia
• Smoking cessation
• Medication review
• Exclude malignancy
• Patient education.

2 Treat the wound pathology
• Improve blood flow, e.g. angioplasty
• Provide compression therapy for venous insufficiency
• Minimise friction, shear and pressure on the wound.

3 Optimise the local healing environment
• Bedside debridement of eschar
• Treatment of infection
∘ Cellulitis: simple antibiotics
∘ OM: extensive orthopaedic surgery
• Maintain adequate wound hydration
• Consider negative pressure wound therapy.

Question 12

What are the indications for reconstructive surgery?

Answer 12

Indications for reconstructive surgery
• Patients should be fully investigated:
∘ Imaging may reveal a dislocated hip or OM.
• Predisposing factors should be corrected if possible.
• Preventative measures in place pre-operatively to prevent recurrence postoperatively.
• Deteriorating conditions are not candidates for reconstruction.
• Patients expected to increase their mobility are treated conservatively (ulcers will improve)

• Surgery is best suited to:
∘ Well-motivated, young patients
∘ Clinically stable conditions
∘ Compliant

Question 13

What are the principles of surgery?

Answer 13

1. Adequate wound excision, including:
   ∘ Surrounding scar
   ∘ Underlying bursa - delineate with methylene blue staining
   ∘ Bone and soft tissue calcifications.
2. Obliteration of dead space.
3. Reconstruction with durable skin.
4. Flaps should not be wasted:
   readvancable flaps should be used. Territories of future potential flaps should not be violated.
5. Flaps are designed as large as possible.
6. Suture lines should lie away from pressure areas.
7. Large drains are empirically left in place for at least 2 weeks post-operatively.

Question 14

How are sacral pressure sores reconstructed?

Answer 14

• Occur in supine patients.
• Can be reconstructed with the gluteus maximus musculocutaneous flap.
∘ Quoted recurrence rate: 16%.
• Can be designed as a rotation or V-to-Y advancement flap.
• The muscle’s greater trochanter insertion can be divided in non-ambulatory patients.
∘ This increases flap mobility.
• Lumbosacral flaps, based on regional perforating vessels, can also be used.
• Use of the superior gluteal artery perforator flap is also described.

Question 15

How are ischial pressure sores reconstructed?

Answer 15

Arise in seated patients.
• Excision of the ischium should be conservative if possible.
∘ Complete removal transfers pressure onto the contralateral ischium.
∘ Excision of both ischial processes can result in perineal ulceration and urethral fistula.

• Can be reconstructed with:
∘ Inferior gluteal artery myocutaneous flap, or the equivalent perforator flap.
∘ V-to-Y advancement based on hamstring muscles.
- Advantage: potential readvancement in case of recurrence.
- Disadvantages: scar tends to lie on the point of maximal pressure; hip flexion places
tension on the closure.
- Cannot be used in ambulatory patients due to the functional donor deficit.
∘ In ambulatory patients, a posterior (gluteal) thigh fasciocutaneous flap can be used.

Question 16

How are trochanteric pressure sores reconstructed?

Answer 16

• Arise in patients that lie on their side, often due to hip flexion contractures.
• Classically reconstructed with the tensor fasciae latae (TFL) flap.
• Overlying skin can be designed as V-to-Y advancement, transposition or hatchet.
• A pedicled ALT flap can also be used, with vastus lateralis included if additional
bulk is required.

Question 17

How are hip joint infections and destruction managed?

Answer 17

• Trochanteric and ischial ulcers can lead to hip joint exposure and destruction.
• Managed by the Girdlestone procedure and wide debridement.
• Defect typically closed with a large muscle flap, e.g. vastus lateralis.
• Rectus femoris can be used for small defects, preserving vastus lateralis for future use.

Question 18

What is the last option in patients with multiple ulcers?

Answer 18

Fillet of thigh
• In the context of multiple ulcers where no other options are available, amputation of a
leg provides tissue as a fillet of thigh flap.
• This is a major undertaking with considerable risks due to long surgery and blood loss.