Negative Pressure Wound Therapy
In Clinical Practice
Robert J. Snyder, D.P.M., C.W.S., MSc ( c )
Medical Director, Wound Healing Center, University
Hospital
Professor ( Adjunct ) Temple University College of Podiatric
Medicine

Objectives
 Define Negative Pressure Wound Therapy
 Describe the science behind NPWT
 Learn contraindications directly associated
with NPWT
 Identify indications for use of NPWT
 Review case studies

Wound Care: Past and Present
 In the past, wound care fell into a trough at
the bottom of the medical mainstream.
 Wounds were foul smelling and infected
and few clinicians were interested in taking
care of them.
 There were no evidence based protocols,
treatment was anecdotal and often
ineffective

Wound Care in the 21st Century: A
Paradigm Shift
 Evidence based approach to wound management
 Understanding of macro and micro-environment
 Appreciation for multi- disciplinary approach to
wound care ( Diabetics, elderly, nursing home
patients, resistant organisms such as MRSA)
 Significant research and new therapies
 Renewed interest and appreciation by the medical
community for wound management
 The medical community has higher expectations
of wound care professionals

Core Healing
Principles
Patient factors
Physical aspects
MACROscopic
environment
MICROscopic
environment

Negative Pressure Wound Therapy:

NPWT Components
 Therapy Units
 Foam dressings
 Semi-Occlusive
Drape
 Canisters

Moist Wound Healing Has Been The
Standard For Wound Care Since The
Mid-1980’s
 Adhesive drape provides semi- occlusive
environment that supports moist wound healing
 Drape is vapor permeable to facilitate gas
exchange ( important when treating wounds with
anaerobic organisms that thrive on oxygen
depleted environment)
Rolstad B, Ovington L, Harris A. Acute and Chronic Wounds. 2000

Foam and Drape
Protectthe wound base from
environmental contaminants
Reduce the risk of friction or shear
Enhance the bodies ability to heal

Mechanisms of Action
 Even distribution of
negative pressure
resulting in a tissue
tension/stress effect
 Active removal of
extracellular debris

Additional Benefits
Decreases peri-wound edema
Increases profusion to the wound
Improves wound nutrition
Deforms cells thereby changing their
genetic signal
Creates active wound contraction

Further Benefits
 Decreases bacterial
colonization
 Increases the rate of
granulation tissue
formation and
epithelialization
 Mitosis is stimulated
and new vessels are
formed as the wound
is drawn closed

Infection Contributes to Various Complications
Including Amputation
Risk factors for
infection:
– Wounds that penetrate to
the bone
– Wounds with a duration
> 30 days
Infection plays a role in about 60% of the – Recurrent foot wounds
DFU cases that result in amputation
– Wounds with a traumatic
etiology
DFU = diabetic foot ulcer. – Peripheral vascular
Lipsky. Diabetes Metab Res Rev. 2004;24:S66.
Lavery, Armstrong, et al. Diabetes Care. 2006;29:1288.
disease

Bacterial burden or infection ?

Microorganisms Are Detrimental
To Wound Healing
 Consume nutrients and oxygen that would
otherwise be directed toward tissue repair
 Release enzymes that breakdown protein
 NPWT reduces bacterial bioburden by removing
stagnant infected wound fluid
 NPWT enhances periwound circulation and
oxygenation, thus improving resistance to
infection
Argenta L, Morykwas M. Ann Plast Surg 1997;38:563-77

NPWT Does Not Replace
Surgical Procedures Or Antibiotic
Therapy, However It May Allow
Wound Progression To Proceed
So That A Less Invasive
Procedure Is Possible

Mechanisms of Action: The
Clinical Picture

Contraindications
Devitalized /Necrotic Tissue
Fistulas
Organs and exposed blood vessels
Malignancy

NPWT Tissue/Eschar:
 All necrotic tissue must be removed prior to
NPWT
 Dead tissue is a portal for pathogen
 Hardened eschar/slough inhibits delivery of
NPWT to underlying tissues
 Hardened eschar/slough may put downward
mechanical pressure on underlying healthy tissues
 Caveat: NPWT may be used with soft slough that
cannot be debrided ( use higher pressures first few
days; may act as debriding agent)

Do Not Use NPWT in Untreated
Osteomyelitis
Underlying bone infection inhibits
healing
Possible progress will regress with
untreated osteomyelitis present
Goals for healing may not be met

Use of NPWT with Osteomyelitis
 Infection must be
treated with systemic
antibiotics
 A combination of
surgical and medical
interventions may be
appropriate prior to
institution of NPWT
 All loose bone
fragments must be
removed

NPWT is Contraindicated with
Malignancy
 Malignant tissue inhibits
any healing process
 Unlike healthy cells,
cancer cells are often not
anchored therefore do not
respond to mechanical
stretch.
 Goals of NPWT
unobtainable in the
presence of malignancy

Precautions
Active bleeding/difficult wound
hemostasis
Anticoagulants ( INR < 3.0 )
Close proximity to vessels/organs
Weakened, irradiated, sutured vessels
Bone fragments
Enteric Fistula

Clinical Indications
Chronic
Acute/Traumatic
Dehisced
Diabetic Ulcers
Pressure Ulcers
Flaps and Grafts
Partial Thickness Burns

Chronic Wound Pathologies
 Venous Stasis
Ulcers
 Pyoderma
Gangrenosum
 Stage III/IV
Pressure Ulcers
 Diabetic Ulcers
 Calciphylaxis

What killed Superman?
Christopher Reeves died on October 10, 2004
of sepsis from complications of a pressure ulcer

Chronic Pathology:
Goals for NPWT
Decompress interstitial spaces
Minimize infectious pathogen
Optimize moist healing environment
Increase perfusion
Initiate an active phase of healing

Atypical Venous Ulcer Confirmed
by Multiple Biopsies

Acute/Traumatic
 Laceration
 Degloving
 Fasciotomy
 Amputation
 Necrotizing
Fasciitis

Acute/Traumatic Pathology:
Goals for NPWT
Decompress third-spaced debris
Collect & quantify volume losses
Protection from accumulation of
infectious pathogen
Maintain perfusion
Enhance active healing

Dehisced Wounds
Sternal
Abdominal
Spinal
Extremity

Dehisced Pathology:
Goals for NPWT
 Stabilize the dehisced wound edges.
 Decompress interstitial edema.
 Assist in the removal of infectious
pathogen.
 Create a splinting effect for the underlying
structures.
 Promote granulation tissue in preparation
for delayed primary closure or healing by
secondary intention.

Dehisced Wound Treated with VAC

Grafts
 Split Thickness
Meshed Grafts
 Bio-engineered tissues
 Abdominal mesh
– Vicryl®
– Marlex®
– Gortex®
– Prolene®

Grafts: Goals of Therapy
Stabilize and bolster graft to recipient
bed
Active removal of interstitial fluid
through meshed regions
Protection from accumulation of
pathogen
Increase perfusion to the new graft

Flaps
Fresh
Compromised
Muscle
Myocutaneous
Musculocutaneous

Flaps: Goals of Therapy
Stabilize & bolster flap post placement
Active removal of interstitial fluid
through suture line
Protection from accumulation of
pathogen

Partial Thickness Burns
Superficial 2nd Degree burns
Deep 2nd Degree burns

Partial Thickness Burns: Goals
of Therapy
Minimize depth of injury in the Zone
of Stasis
Assist in recipient bed preparation
Post-graft placement
Protection from accumulation of
infectious pathogen

Cost Considerations
 NPWT may reduce expenses related to wound
care
 Decreased number of dressing changes
 Skilled nursing time is reduced
 Patients may be transferred more quickly to less
acute and less expensive care settings
 Healing rates are faster when compared with
saline soaked gauze
Weinberg Group, Inc. May 1999

Case Studies

54 year old diabetic male, s/p
incision and drainage of deep space
abscess

Wound appearance approximately 1
month after VAC Therapy instituted

Complete healing approximately 10
weeks after using VAC Therapy

78 y/o diabetic male with decubitus
heel ulcer

Patient had angioplasty, then underwent wound and
bone debridement. A cadaveric allograft was applied
and VAC therapy was instituted. Infection was
treated with antibiotics.

Combination therapy creates
significant clinical improvement

The patient continues to improve. Periwound
maceration was treated by protecting the tissue
with a hydrocolloid and increasing VAC
pressures from 125 to 150 for a short period of
time

 67 year old male with IDDM
 H/O blockage of posterior tibial opened
with angioplasty
 Burned his foot with a heating pad
 Severe neuropathy
 Presented to the office with an infection
requiring hospitalization

After VAC Therapy and Split-
Thickness Skin Grafts

 Extremely painful lower leg ulcer that
occurred after the patient bumped her leg on
a dishwasher door
 H/o diet controlled diabetes and
inflammatory bowel disease
 Vascular examination normal
 Orthopedic and neurological exams
unremarkable

Pyoderma Gangrenosum

Multidisciplinary treatment with intra-
lesional injections, Infliximab, and
NPWT/VAC®

Application of biologic skin
substitute plus continued use of
Infliximab and VAC®

PG After 12 Days of VAC Therapy
Along with Conventional Therapy

S/P Split-thickness Skin Graft

 Patent is a 66 year old white male
with IDDM, S/P recent distal bypass;
developed heel abscess which tracked
to bone.
 Patient underwent extensive wound
debridement on an emergent basis to
save his life and limb
 PMMA beads were utilized
 C&S revealed poly- microbial
organisms including MRSA
 Patient optimized from vascular
standpoint
 Semmes- Weinstein greater than 5.07
 H/O cardiac disease requiring beta-
blockers and renal insufficiency
 Patient was ambulatory prior to
surgery and does not have a
pacemaker

 Additional treatment consisted
of VAC therapy, two courses of
vancomycin, combination
therapy with multiple
antibiotics, several
debridements, and application
of skin substitute, followed by a
split- thickness skin graft
 Placement of split-thickness
split-
skin graft and drain to evacuate
small pocket of serous drainage
and manage dead space

Patient developed a wound dehiscence at the distal site and a tract at the
central portion of the wound. There was frank white-yellow purulence.
C& S revealed MRSA.

The patient was taken back to surgery and additional infected tissue was
removed. The 4th toe was filleted and the skin was used as a flap to close
the defect. The patient was placed on Linezolid 600 mg po q12h. VAC ®
was continued over the incision post operatively

All Surgical Sites Healed

Patient required emergency open amputation
below the knee for gas gangrene. Above knee
revision was contemplated

Wound after approximately two
months of VAC®

VAC® combined with biologic
skin substitute

 Stage IV Ulceration in
Diabetic Male with PVD
and Neuropathy
 H/O BKA contralateral
limb
 H/o remote MI, renal
insufficiency,
hypertension,
dyslipidemia
 Non-palpable pedal
pulses, foot cool, capillary
refill delayed
 Semmes-Weinstein greater
than 5.07

S/P angioplasty and extensive wound
debridement. IV antibiotics and
PMMA beads were used. VAC therapy
and HBO started

Several skin substitutes were utilized;
VAC therapy and HBO continued
through placement of split-thickness
skin graft

Summary
 NPWT represents an evidence based
modality that stimulates wound closure by
providing a moist healing environment,
reducing peri-wound edema, increasing
peri-wound circulation, decreasing bacterial
bioburden, and increasing granulation tissue
 NPWT is safe and cost effective when used
within appropriate guidelines and
indications