New Advances In Predicting Wound Healing
With the preponderance of wounds and the cost of chronic wound healing continuing to soar, this author offers a provocative look at emerging innovations such as medical hyperspectral technology and real-time polymerase chain reaction that may reinvent the diagnostic workup of chronic wounds.
Chronic lower extremity skin ulcerations affect millions of people in the United States alone. These ulcerations are defined by the Wound Healing Society as wounds that have “failed to proceed through an orderly and timely process to produce anatomic and functional integrity, or proceeded through the repair process without establishing a sustained anatomic and functional result.”1 The relapsing course of wound healing poses a significant management challenge to healthcare professionals and imposes an astounding economic burden on healthcare.2
The total direct cost of chronic wounds in the U.S. — including wound diagnostic and surgical procedures, pharmaceuticals, wound closure devices and hospital and physician charges — amounts to an estimated $20 billion annually. Medicare expenditures for lower extremity ulcer patients are, on average, three times higher than those for Medicare patients in general.3-5 In addition to the tremendous medical and financial impact, this prolonged and often interrupted healing process also affects the patient’s quality of life and activities of daily living because of impaired mobility and substantial loss of productivity.2 Moreover, chronic ulcers are frequently associated with infections that may lead to some form of lower extremity amputation or induce life-threatening situations.6-7
Chronic ulcerations may be secondary to a plethora of etiologies including pressure, metabolic, trauma, venous, arterial, diabetes or a combination of the above.7 Treatment protocols for chronic ulcerations include adequate and appropriate debridement, nutrition, infection control, ensuring vascular adequacy and correction of the underlying etiology such as compression for venous insufficiency ulcers and mitigation of pressure for plantar and decubitus ulcers.8,9 Further, clinicians often incorporate the use of advanced wound healing modalities such as bioengineered skin equivalents, acellular matrix based materials, negative pressure wound therapy, hyperbaric oxygen therapy and topical growth factors to help accelerate the healing of chronic wounds.6,10-12 Although these efforts show some degree of success in the healing of both simple and complex chronic ulcerations, a good portion of these wounds remain unhealed.
These clinical observations are consistent with and supported by objective healing rates described in a myriad of published and unpublished industry-sponsored randomized trials.6,13,14 It then stands to reason that the chronic ulcerations that are more recalcitrant to treatment may have unresolved pathophysiologic and metabolic conditions that continue to alter and impair the highly integrated cellular and biochemical processes of healing.5
Accordingly, let us take a closer look at just a few of the latest advances in biomedical technology that may help predict ulcer healing and assist in the management of chronic ulcerations.
Medical Hyperspectral Technology: Can It Have An Impact In Vascular Assessment?
Peripheral arterial disease (PAD) is commonly associated with chronic ulcerations and non-invasive vascular tests are part of the routine workup in this patient population. These tests involve inspection of the limbs, palpation of pulses, ankle brachial pressure index, segmental pressures, pulse volume recordings, toe systolic pressures and toe brachial pressure indexes.15-18 Researchers have also advocated optical techniques such as photoplethysmography, which uses infrared light to assess blood flow to the digits and lower limbs, and transcutaneous oxygen tension measurements for the detection of peripheral arterial disease and prediction of wound healing.19-22