The cost of wound debridement: a Canadian perspective

Abstract

Debridement is integral to wound bed preparation by removing devitalised tissue, foreign material, senescent cells, phenotypically abnormal/dysfunctional cells (cellular burden) and bacteria sequestrum (biofilm). While the body of evidence to substantiate the benefits of debridement is growing, little is known about the cost‐effectiveness of each debridement method. The purpose of this analysis was to compare cost‐effectiveness of various debridement methods and clinical outcomes to help inform clinicians and policy makers of the cost‐effectiveness associated with the various types of therapies and the impact they can have on the Canadian health care system. Results indicated that sharp debridement was the most cost‐effective followed by enzymatic debridement method.

Introduction

The healing of acute wounds follows a predictive sequence of overlapping phases including inflammatory, proliferative, reepithelialisation and remodelling stages 1. The complexity of healing depends on many intrinsic and extrinsic factors that regulate the complex biochemical and cellular events that culminate in closure of a wound with fibrotic scar tissue. Unlike acute wounds, chronic wounds such as pressure ulcers (PUs), venous leg ulcers (VLUs) and diabetic foot ulcers (DFUs) do not always follow predictable temporal overlapping phases of healing owing to disruption of one or more elements of the healing process. Treatment of chronic wounds requires a systematised approach under the tenets of ‘wound bed preparation’, which highlights the key individual components of wound care 2. Within this framework, it is important to treat the cause and address patient‐centred concerns prior to local wound care. Best practices to prepare the wound bed for healing include debriding of unhealthy and non‐viable tissue, controlling infection and bacterial bioburden, maintaining moisture balance and addressing the unhealthy wound edges.

Debridement is integral to wound bed preparation by removing devitalised tissue, foreign material, senescent cells, phenotypically abnormal/dysfunctional cells (cellular burden) and bacteria sequestrum (biofilm). Provided the wounds have the potential to progress towards healing, debridement has been demonstrated to accelerate healing 3. While the body of evidence to substantiate the benefits of debridement is growing, little is known about the cost‐effectiveness of each debridement method. The purpose of this analysis was to compare cost‐effectiveness of various debridement methods and clinical outcomes to help inform clinicians and policy makers of the cost‐effectiveness associated with the various types of therapies and the impact they can have on the Canadian health care system.

Background

Debridement of necrotic tissues in chronic wounds can be achieved by a number of methods described as surgical (conservative sharp and surgical sharp), autolytic, biological (involving maggots), mechanical and enzymatic (collagenase) 4. Methods of debridement may be deployed as a single therapeutic modality or may be serially combined to optimise the debridement process. Selecting the proper combination of debridement techniques requires evaluation of the patient's individual needs and the available resources to achieve optimal clinical outcomes.

Sharp debridement

Surgical sharp debridement usually involves sharp instruments such as scalpel, scissors or curette to remove tissue from the wound. Conservative sharp debridement may involve trimming of superficial non‐viable tissue without causing any bleeding as opposed to surgical sharp debridement that usually involves more extensive debridement to reach the vascular layer. Sharp debridement is preferred when there is a large amount of necrotic tissue and/or eschar (dried scab or slough) or if there is evidence of advancing tissue infection 5. In a retrospective study of data from two randomised controlled trials of 366 VLUs and 310 DFUs over 12 weeks, Cardinal et al. 6 reported a significant higher median wound surface mean reduction with sharp debridement compared with no debridement in patients with VLUs (34%, P = 0·019). Frequent surgical debridement was associated with wound closure in both ulcer types (P = 0·007 VLU and P = 0·015 DFU). Although non‐viable tissue can be promptly removed by sharp debridement, it is not always possible owing to pain, bleeding potential and lack of clinician expertise.

Autolytic debridement

Autolytic debridement involves the removal of non‐viable tissue by promoting the activities of phagocytic cells and endogenous enzymes (matrix metalloproteinases). Moist interactive dressings such as alginates, transparent films, hydrogels and hydrocolloids are used to create an environment that optimises the body's natural processes to dissolve necrotic tissue. According to a Cochrane review of debridement in DFUs, hydrogel was related to faster healing rate compared with gauze dressings [relative risk (RR) = 1·84; 95% confidence interval (CI): 1·3–2·61] 7. However, autolytic debridement takes the longest to work and relies on the patient's own cells and enzymes to remove necrotic tissue. It is now well known that for many patients, their underlying condition and comorbidities may prevent the migration and performance of cells that provide the enzymes to debride. Some of these conditions include diabetes, poor nutritional status, cancer, advanced age, corticosteroid use, vascular disease (poor circulation), immune deficiency, infection, smoking, cold, stress, increased adipose tissue and paralysis. It has been recommended that if tissue autolysis is not evident within 24–72 hours, an alternate form of debridement should be used 5.

Enzymatic debridement

Exogenous enzymes such as collagenase can be used to accelerate the debridement process. Collagenase is a water‐soluble proteinase that selectively breaks down denatured collagen 8, especially those that anchor necrotic tissue 7. Normal collagen is surrounded and protected by mucopolysaccharide sheaths from the activity of collagenase. In a randomised, controlled trial comparing collagenase to autolysis in a population of long‐term care facility patients, it was demonstrated that at 42 days of therapy 85% of the collagenase patients had achieved a clean wound bed when compared with 29% in the autolysis arm 9. It has also been suggested that collagenase may have other effects on wound healing such as angiogenesis, enhancement of keratinocyte cell proliferation and migration and inhibition of the production of inflammatory cytokines and metalloproteinases 10, 11. Currently, in Canada and the USA, Santyl^® ointment (collagenase; Santyl, Healthpoint Biotherapeutics, Fort Worth, TX) is the only enzymatic debriding agent commercially available. Systematic review of the existing literature by Ramundo and Gray 12 has confirmed that collagenase is safe and effective.

Biological debridement

Biological debridement involves the use of maggots to remove non‐viable tissue. Sterile larvae of the blowfly (Phaenicia sericata or Lucilia sericata) are able to digest soft necrotic tissue, cellular debris, serous drainage and pathogenic bacteria. Proteinases secreted by the larvae selectively digest non‐viable tissue 13. Although this has been shown to have clinical applications in the debridement of some wounds, the stigma of using maggots needs to be overcome by both health care professionals and patients 14. In addition, increased level of pain with maggot therapy warrants attention prior to initiation of the therapy.

Mechanical debridement

Mechanical debridement is achieved by using physical forces to remove wound debris. Wet‐to‐dry dressing technique is one of the most popular forms of mechanical debridement. As the wet dressing dries, necrotic materials adhere to the dressing fabric and are pulled away when the dressing is removed with force. This process is very non‐selective, can remove viable as well as necrotic tissue, is very painful for the patient and can cause further trauma to the wound. Hydrotherapies such as whirlpool, pulsatile lavage and irrigation systems are available, but warrant extra precautions to limit cross‐contamination and aerosolising bacteria droplets.

Methods

The purpose of this study was to determine the costs associated with the various debridement methods available to achieve a clean wound base for healing, in Canada. The analysis was based on expert opinions on a hypothetical patient with a chronic wound that required debridement. The size of the wound was assumed to suit a 10 × 10 cm dressing and the time of therapy was defined as time to achieve a clean wound bed. Assuming that patients will receive best practices based on the aetiologies of the wound types (e.g. compression for VLUs and off‐loading for DFUs), only direct and indirect costs associated with wound debridement including health care personnel (e.g. physicians, nurses and support workers), supplies (e.g. dressing, equipment, medical grade maggots and collagenase), complications associated with the treatment (e.g. pain, infection and management of complications), operating room, transportation (e.g. transfers for care) and out‐of‐pocket expenses (e.g. parking) were estimated. These resources were estimated based on existing data from federal, provincial and regional sources. Average time to achieve clean wound bed was determined by the experiences of various wound care clinics and published literature. Assumptions and estimations based on clinical experiences and literature review for the analysis are represented in Table 1. A number of sources were used to determine the unit costs (Table 2). For this analysis, resources for each wound care management option were multiplied by costs using the following formula:

$${\mathrm{Overall}\mathrm{Cost}}_{\mathrm{WT}}=R_{\mathrm{WR}}{}^{*}{C}_{\mathrm{R}}$$

where Cost_WT is the cost of wound treatment, R _WR is the rate of wound resource and C _R is the cost of resource.

Table 1.

Assumptions used to determine resources

Debridement method, time to a clean wound bed	Procedures/materials	Potential complications/other expenses	Assumptions
Surgical sharp, 3 weeks 15	· Surgical debridement once a week for 3 weeks · Dressing changes every 3–4 days · 1–2% of patients will go to the OR · 50% of the time a hydrogel dressing used, 50% use of hydrocolloid dressing · 20% transferred from a long‐term care facility to a wound clinic three times	· 5% of patients will have a bleed requiring suture · 50% of patients will have a minor bleed · 50–60% of patients will have infection requiring medication · 20% will experience pain requiring medication · Patients will incur out‐of‐pocket expenses (parking) for three visits to the hospital/wound clinic	· Performed by a nurse specialist 30% of the time and by a physician 70% of the time
Conservative sharp, 6 weeks	· Dressing changes will occur every 3–4 days · 50% of the time a hydrogel dressing will be used and 50% of the time a hydrocolloid dressing · 5% of the patients will be transferred from a long‐term care facility to a wound clinic for two debridements	· 50–60% of patients will experience infection and will receive medication · 50% of patients will have pain and will receive medication	· Would occur at home by a homecare nurse 60% of the time and in an institution by a nurse 40% of the time · Patients seen initially by a nurse specialist 70% of the time, by physician 30% of the time for assessment and then for one follow‐up visit
Autolytic, 10 weeks 9	· Dressing changes occur every 3–4 days at home by a homecare nurse 60% of the time and 40% in an institution by a nurse · 50% use of hydrogel dressing and 50% of the time hydrocolloid dressing used	· 10% of patients will experience an infection and will require medication	· Assessed by a nurse once every 2 weeks (five times) and twice by a physician (one initial assessment and one follow‐up visit
Enzymatic, 4 weeks 9	· 35% of the patients will be in institution, collagenase applied daily by nurse · 65% of patients treated at home—homecare nurse three times a week, family caregiver for remainder of days · 15% of patients will receive Hydrofera Blue prophylaxis for infection	· 10% of patients will experience infection requiring medication	· Would be seen by a nurse specialist once every 2 weeks (two times) and twice by a physician (once at initial assessment and once at follow‐up)
Biological, 3 weeks 16	· Patients will receive application of maggots three times per week by a nurse	· 30% experience pain requiring one physician visit and medication · Patient parking for each trip to the hospital	· Be assessed by a physician initially and once for follow‐up
Mechanical, 6 weeks	· 60% of patients will be in an institution where nurses will perform mechanical debridement daily	· 70% of patients will experience an infection requiring medication · 20% of patients will experience pain requiring medication	· Seen by a specialist nurse once every 2 weeks (three times) and once by a physician for an initial assessment and once for follow‐up

Table 2.

Unit cost list for wound care

Variable	Unit cost	Source
Personnel
Nurse: outpatient/homecare	$40·00/hour	Canadian Federation of Nurses Unions: Ontario Nurse's Association 17
Wound care specialist nurse	$45·00/hour	Canadian Federation of Nurses Unions: Ontario Nurse's Association
Physician: outpatient visit	$32·35	Ontario Schedule of Benefits 18
Physician: surgical consultation	$118·50	Ontario Schedule of Benefits
Personal support worker	$20·00	Canadian Federation of Nurses Unions: Ontario Nurse's Association
Equipment/supplies
Dressings: alginate for suture	$2·60	Clinical Expert Opinion
Disposable sterile dressing tray	$3·51	Medline Wound Care Tray: ProMedical Supplies
Gloves	$0·64	Wetmore, 2002 19
Moist gauze	$0·49	Price Catalogue: Approvisionnements Montreal: 2009–2010 20
Semi‐permeable dressing	$2·60	Wetmore, 2002
Allevyn	$3·98	Price Catalogue: Approvisionnements Montreal: 2009–2010
Dressings: hydrogel	$2·62	Price Catalogue: Approvisionnements Montreal: 2009–2010
Dressings: barrier wipe	$1·50	Price Catalogue: Approvisionnements Montreal: 2009–2010
Dressings: hydrocolloid	$2·50	Price Catalogue: Approvisionnements Montreal: 2009–2010
Forceps	$11·69	Wetmore, 2002
Scissors	$11·69	Wetmore, 2002
Scalpel: one per procedure (disposable versus reusable)	$1·17	Wetmore, 2002
Bleeding: requiring suture	$146·30	Extra supplies for suture (wholesale) + doctor visit
Bleeding: not requiring suture	$0·00	No extra cost
Curette: one per procedure	$23·38	Wetmore, 2002
Enzymatic debriding agent	$87·50	Canadian Healthpoint price list 21
Hydrofera Blue	$8·80	Price Catalogue: Approvisionnements Montreal: 2009–2010
Medical‐grade maggots	$68·75	Clinical Expert Opinion
Dacron mesh leave maggots on for 48 hours with dressing‐take maggots out and replace	$3·00	Price Catalogue: Approvisionnements Montreal: 2009–2010
Permeable gauze + tape	$2·60	Wetmore, 2002
Complications
Infection: Dr visits X2	$68·75	Ontario Schedule of Benefits
Pain: Dr visits X1	$41·20	Ontario Schedule of Benefits
OR for surgery	$4604·00	OCCI‐$4485 2008 + inflation 22
Out‐of‐pocket expenses
Patient out‐of‐pocket expenses (family gas parking)	$20·00	Split—community/academic parking
Medications
Antibiotic for infection	$0·24	http://www.canadadrugs.com—1 cap wholesale US $
Analgesic NSAID for pain	$2·00	http://www.canadadrugs.com—1 cap wholesale US $
Anaesthetic for procedure	$7·31	http://www.canadadrugs.com—1 cap wholesale US $
Local anaesthetic	$40·75	http://www.canadadrugs.com—1 cap wholesale US $
Transportation
Transfer from long‐term care (to and from)	$300	Ontario Schedule of Benefits

Sensitivity analyses were conducted. Because of the nature of the variables involved, a probabilistic analysis (e.g. a Monte Carlo analysis) did not appear to be an appropriate choice. Instead, two variables were systematically altered using a factorial approach. The two main cost drivers, that is, number of weeks for the wound to heal and the number of visits per week were systematically altered and the values used were 25% above and 25% below the base case values that were provided by the experts.

Results

Based on the resources used and the assumptions made, the results show that extensive surgical sharp therapy to remove all unwanted tissue ($1039) is the least expensive debridement method followed by conservative sharp treatment ($1120), enzymatic ($1265), autolytic debridement ($1504·73), mechanical debridement ($1840·74) and biological treatment with the highest overall cost ($2151) (Figure 1). Sensitivity analyses were conducted by estimating the cost associated with 25% above and 25% below the projected values for the number of weeks for the wound to heal and the number of visits per week required to achieve clean wound bed.

Figure 1.

Cost of chronic wound debridement (base case).

In the base case analysis, ranking of debridement methods from lowest to highest cost was surgical sharp, conservative sharp, enzymatic, autolytic, mechanical and biological. In the sensitivity analysis, the lowest resource scenario (75% of the number of visits and 75% of the number of weeks to a clean wound bed), the ranking of overall cost, from lowest to highest, was conservative sharp, surgical sharp, autolytic, enzymatic, mechanical and biological. In the scenario of the greatest use of resources (125% of base case number of visits and 125% increase in time to a clean wound bed), the ranking from lowest to highest cost was surgical sharp, enzymatic, conservative sharp, autolysis, mechanical and biological. Therefore, it appears that speeding up the debridement process and using fewer resources has the potential to reduce costs. Similarly, an increase in these parameters increases the cost. In assessing the cost for the base case enzymatic scenario ($1264·69) versus autolytic, autolytic was shown to cost less in three instances: (i) when the time to a clean wound bed was reduced by 2·5 weeks (down to 7·5 weeks from 10) and nursing visits were reduced from 3·5 to 2·6/week ($1037·98); (ii) when nursing visits were reduced to 2·6/week ($1233·71) and (iii) when the time to a clean wound bed was reduced to 7·5 weeks ($1241·24). Each of these scenarios still resulted in more nursing visits and a longer time to a clean wound bed for the autolytic method than for the enzymatic treatment.

Discussion

Debridement is integral to wound management. While there are different methods to remove necrotic tissue in order to promote healing, little is known about the associated cost. Lewis et al. 23 reviewed the literature to determine the cost‐effectiveness analysis of various autolytic debridement methods. There was some evidence to suggest that the use of modern dressings to promote autolytic debridement required lower costs than the gauze dressings to achieve the same clinical outcome. According to the current analysis and estimation, surgical sharp debridement and conservative sharp debridement are the most efficient ways to achieve a clean wound bed and therefore the least costly of all of the debridement methods. Enzymatic method was ranked the third least costly. Biological and mechanical debridement methods were the most expensive. The cost differential was attributed to the length of time and frequency of treatment resources to complete wound debridement. Therefore, it appears that speeding up the debridement process has the potential to reduce costs. According to the analysis, autolytic debridement often requires a longer duration and more frequent nursing visits, rendering a higher cost to prepare a clean wound bed than other methods.

Consistent with the finding of this analysis, Soares et al. 14 documented that biological debridement using larval therapy incurred a higher cost ($140·57 more per participant per year; 95% CI: £491·9–£685·8) than treatment with hydrogel. In a similar analysis using data from published literature and decision analysis methodology (modified Delphi process), Mosher et al. 24 concluded that enzymatic debridement was more cost‐effective than mechanical debridement. Using a hypothetical elderly female patient in a long‐term care facility with a new full‐thickness PU, they assessed therapy for 1 month with four different debridement methods: autolysis, wet‐to‐dry dressings, collagenase (Santyl) or fibrinolysin. The clinical endpoints evaluated were time to a clean wound bed and risk of infection. The cost‐effectiveness of each method was also calculated. Overall, the patient was most likely to have a clean wound bed after 2 and 4 weeks of treatment with collagenase. The total cost for 1 month of treatment (in 1995 US dollars) was $610·96 for collagenase, $920·73 for autolysis, $986·38 for fibrinolysin and $1008·72 for wet‐to‐dry dressings. It was also found that the risk of infection was less likely for enzymatic treatment than for patients treated with autolysis and wet‐to‐dry dressings.

Muller et al. 25 conducted a prospective randomised trial in 24 female patients (ages ranging from 65 to 79) with grade IV pressure sores on the heel following orthopaedic surgery. They compared a collagenase‐containing ointment and a hydrocolloid dressing. They also conducted an economic assessment of the two treatments (costs in 1998 Dutch guilders). The primary outcome parameter for efficacy and the subsequent economic analysis was complete wound healing (total epithelialisation). The results showed that with respect to success of treatment and time until wound closure, 91·7% of the collagenase patients were treated successfully compared with 63·6% of the patients in the hydrocolloid group (P < 0·005). It was demonstrated that the more rapid healing observed following the use of collagenase reduced the materials and the hospital personnel costs, showing this treatment to be more cost‐effective.

Not all patients are suitable for surgical debridement methods owing to patient status and access to medical personnel able to perform the procedures. In Canada, biological therapy is not commonly used because of limited access to medical‐grade maggots and the stigma attached to the procedure. The use of mechanical therapy is declining because wet‐to‐dry is the least specific method in that it often removes a large amount of viable tissue along with necrotic tissue, is associated with increased infection rates and is often very painful for patients. Furthermore, devices used for mechanical debridement are not readily available to all clinicians. Therefore, patients not suitable for these above mentioned therapies will receive autolytic or enzymatic treatment for debridement of a chronic wound. From this analysis, using the assumption that enzymatic therapy achieves a clean wound bed faster than autolytic therapy, enzymatic treatment is less costly than autolysis in the Canadian health care system. It uses fewer health personnel resources as family members are often trained to apply ointment daily and change dressings. Enzymatic therapy also allows patients to undergo treatment at home and achieving results faster than autolytic therapy may reduce infection rates and increase healing times. The sensitivity analysis demonstrated that the time to a clean wound bed is the key factor driving the cost of wound debridement.

This analysis demonstrates that for a specific hypothetical patient, when debridement methods are compared, surgical debridement is the fastest and least expensive modality, followed by enzymatic, autolytic, mechanical and biological therapies. Indeed, the medical condition of the patient and the nature of each wound are unique and this will require individualisation of debridement therapy. Careful consideration of a variety of factors such as the patient's condition, the goals of care, ulcer/periulcer status, type of wound, quantity and location of necrotic tissue, presence of infection, the care setting and professional accessibility/capability is needed when choosing a debridement method or a combination of treatment modalities.