Choosing the Best Debridement Modality to 'Battle' Necrotic Tissue: Pros & Cons

As clinicians wage “war” against chronic wounds, choosing the proper debridement “weapon” with which to do battle can be challenging and fraught with risks. This article discusses wound debridement approaches, as well as the pros and cons of each.

The term “debridement” has several different pronunciations, the most common being duh-breed-mint. Clinicians in the northeast will often call the process of removing necrotic tissue from the wound bed dee-bride-munt. A third iteration involves the French custom of making the “t” silent at the end, culminating in the fanciest pronunciation of all: doo-bride-maw. While there is significant disagreement on the correct elocution of the word, the literature is clear that proper debridement is critical to propel wounds toward healing. Necrotic tissue, if left unchecked in a wound bed, prolongs the inflammatory phase of wound healing and can lead to wound infection.^1,2 A common theme whispered among wound industry professionals is that physicians and providers are often hesitant to debride too aggressively for fear of bleeding complications, making the wound larger, or they are reluctant to do any procedure that would cause their patients inordinate pain. Additionally, wound specialists often aren’t sure how deeply to debride, when to stop debriding, or whether the tissue left in the wound bed is healthy or nonviable. This leads to “staged” procedures that can take weeks or months to remove nonviable tissue, as opposed to removing all necrotic tissue during the initial debridement (which would be ideal in a perfect world). Further complicating the issue is recent literature suggesting that most wounds that appear to be “clean” actually contain invisible biofilm that delays wound healing, and that debridement of clean wounds can help remove the biofilm.³ Yet, even with debridement, biofilm has been shown to recur and fully mature within 2-3 days post-debridement. Does this mean patients with “clean” wounds should be brought back to the clinic twice per week for debridement to eliminate biofilm and prevent it from recurring? Insurance companies and patients would likely balk at the idea, but it does raise these legitimate questions: When should a wound be debrided? How often? How aggressively?

As clinicians wage “war” against chronic wounds, choosing the proper debridement “weapon” with which to do battle can be challenging and fraught with risks. The following is a summary of wound debridement modalities in the modern clinician’s arsenal, including a discussion on the pros and cons of each choice. The associated wound images are meant to serve as an example of wounds that have been definitively cleaned using each modality. (See Figure 1) 

Surgical Selective Debridement at the Bedside

Surgical selective debridement is the removal of nonviable surface tissue only with a curette or scalpel, with no removal of healthy tissue occurring (hence the term “selective”⁴). There is usually very minor bleeding and pain involved with selective debridement. Wound anesthesia can usually be achieved with topical 2% lidocaine gel (or may not be required at all). Since all chronic wounds are contaminated with surface bacteria and are not sterile by definition, there is no need to bring patients to a sterile operating room (OR) just for a routine bedside selective debridement. Hence, sterile gloves are not required, although a clean technique is advised. With recent literature suggesting that invisible biofilms start to recur 24 hours after a debridement and can become fully mature within three days,³ it is reasonable to use a selective debridement to clean wounds that don’t exhibit obvious slough or nonviable tissue. Removal of biofilm can prevent wound infection and lead to faster healing.³ PROS: Rapid. Can be performed by physicians, mid-level providers, physical therapists, and registered nurses who have been trained and certified in wound debridement. For mostly clean wounds with biofilm or surface slough only. Can be repeated weekly. Topical anesthesia sufficient. No general anesthesia required. Cost-effective. CONS: Does not remove significant amount of necrotic tissue in wounds with heavy bioburden or infected tissue.  (See Figure 2) 

Bedside Surgical Debridement

Bedside surgical debridement has been considered the “gold standard” of necrotic wound treatments for decades. Like selective debridement, this is a non-sterile debridement requiring only a clean technique. The instruments of choice are usually a curette, a scalpel, scissors, or a rongeur. Recent literature suggests that wounds that are surgically debrided more often exhibit a higher healing rate.^5-7 Surgical debridement of necrotic tissue should get down to the level of healthy bleeding tissue. Hemostasis is a legitimate concern, however. Silver nitrate sticks, topical adrenaline, and topical hemostatic dressings are often not adequate to stop bleeding after aggressive debridement. Obtaining and utilizing a surgical-grade electrocautery device for bedside debridement is critical to allowing providers to remove the maximum amount of necrotic tissue without fear of bleeding complications that result in patients visiting the emergency department (ED), or worse. Wound anesthesia can usually be achieved with topical 2% lidocaine gel or injectable 1% lidocaine. Buffering injectable 1% lidocaine with 8.4% sodium bicarbonate in a 9:1 ratio has been shown to decrease the burning pain of the injection. The 1% lidocaine with epinephrine can be injected to yield a combination of anesthesia and hemostasis.^8,9 Prior to any skin graft or skin substitute, it is important that a thorough debridement be performed in order to prepare the wound bed to best receive the graft. When a skin graft or skin substitute fails to improve the wound, the first question should be: Was the wound bed adequately debrided of all nonviable tissue beforehand? Overly aggressive debridement that involves excessively wide excisions or removing perfectly healthy neoepithelium and dermis are not desirable and should be avoided. PROS: Excellent for basic wounds. Can be rapid and be repeated weekly. No general anesthesia required. Topical anesthesia is often sufficient. Cost-effective. Note that surgical debridement can only be reported weekly if you are removing subcutaneous tissue, muscle, or bone. Otherwise, you are selectively debriding. In addition, many payers have limits on the number of debridements that can be performed on a wound. CONS: Often painful. Difficult to anesthetize. Hemostasis often difficult to achieve without surgical electrocautery device. Poor lighting. Difficult to position patient properly. Complex cases can be overly time-consuming due to limited resources at bedside. Must be a physician or an advanced-level provider to perform. (See Figures 3-8) 

Surgical Debridement In The Operating Room

Some wounds are too large and complex to debride at the bedside. Due to the amount of tissue needed to be excised, the risk of bleeding increases significantly. Also, the amount of pain involved often cannot be treated with topical or injectable analgesics. Pain and bleeding risk are the two main factors that require patients to be debrided in the OR. With an anesthesiologist or certified registered nurse anesthetist handling the patient’s pain, the surgeon is free to focus on the wound debridement with a relaxed, immobile patient. Higher-powered electrocautery devices used in the OR can be used to achieve hemostasis that would be more difficult in the clinic or bedside setting while using an inadequate cautery pen or silver nitrate stick. PROS: For large, complex, or excruciating wounds, general anesthesia or nerve block is the only option to aggressively remove necrotic tissue. Wounds can be serially debrided in the OR, prepped for skin graft or flap, and closed. CONS: Hard to repeat weekly for a prolonged period of time. Postoperative pain is often still an issue. More expensive than bedside procedures. Elderly patients are often not candidates to undergo general anesthesia. Must have OR privileges or be able to find a surgeon willing to do wound debridements. (See Figures 9 and 10) 

Low-Frequency Ultrasonic Debridement

Not to be confused with high-frequency ultrasonic “misting” devices that do not debride, low-frequency ultrasonic debridement devices are a highly sophisticated approach to necrotic tissue and biofilm removal. Low-frequency ultrasonic energy (20-40 kHz) is so powerful that it is used by neurosurgeons to cut spinal bone. In the wound center, necrotic and osteomyelitic bone can be debrided ultrasonically as well. Wound applications utilize specialized probes to debride necrotic eschar, fibrin, and slough. Ultrasonic debridement removes only nonviable tissue and does not harm healthy tissue. This is especially helpful when the wound specialist is unsure of how deeply to debride in order to get to healthy tissue.^11,12 PROS: For wounds with chronic bioburden, provides excellent debridement on a microscopic level. Ultrasonic energy can penetrate beneath the surface of wounds, rupturing bacterial cell walls. Causes minimal capillary bleeding that is usually much easier to control than surgical debridement. Excellent choice to clean wounds prior to skin grafts or skin substitutes. Best when used in conjunction with surgical debridement. CONS: Can actually be more painful than surgical debridement due to abrasive vibration of probe tip. Often associated with fluid spray that is hard to control at bedside without wall suction. Expensive device, with expensive disposables. Usually does not increase reimbursement for hospital or providers beyond selective debridement code. (See Figures 11-14) 

Mechanical Debridement

This type of debridement removes unhealthy tissue by way of abrasive force. Examples include gauze, soft fiber, wet-to-dry, and pulse lavage. Nurses cleaning wounds with non-sterile gauze during dressing changes is the most common form of mechanical debridement across the spectrum of facilities. Recently, soft-fiber has been used to scrub wounds and remove loosely adherent, nonviable tissue with less pain.^13,14 The most notorious mechanical debridement method is wet-to-dry wound dressings, and it is unfortunately still being taught in residency programs across the country.  Wet or moistened gauze is applied to the wound bed and then allowed to dry out while it adheres to nonviable tissue. The dry gauze is then removed by peeling off the dressing, thereby removing the nonviable tissue (and often viable tissue as well). This method is nonselective and often very painful. Also, dressing fibers can be left behind in the wound bed, eliciting a foreign body response and increased risk of infection.^13-15 Pulse lavage is commonly utilized in the OR or ED for wounds that contain heavy contamination, such as trauma wounds and necrotizing infections. Not commonly used in wound centers, hydrotherapy (whirlpool) has largely fallen out of favor due to increased risk of infection as well as nonselective damage and maceration of healthy tissue. PROS: Can be performed by nurses in any facility on any size wound that has nonviable tissue. Supplies are often readily available. Mechanical scrubbing of wounds is very inexpensive. CONS: Very slow process. Often painful, especially with wet-to-dry dressings. Wet-to-dry is a daily dressing change, labor intensive, and therefore very expensive. Mechanical debridement is usually superficial only and does not remove dead tissue down to bleeding healthy tissue. (See Figure 15) 

Autolytic Debridement

Autolytic debridement is the use of a person’s own body fluids that contain endogenous enzymes to interact with the wound dressing to soften and remove nonviable tissue. Examples include hypertonic saline, Manuka honey (Leptospermum scoparium), hydrogel, hydrocolloids, and transparent film. The goal is to maintain a moist wound environment. Generally, this is a simple and safe dressing selection that is not a preferred method of debridement for those patients who require a faster debridement or have an active infection in the wound, unless it’s done in conjunction with surgical debridement.¹⁵ PROS: Safe and easy to use for those needing minor debridement. Less pain involved. Can be utilized in any type of setting. Topical applications are usually less expensive than other dressing selections. CONS: Risk of periwound maceration. Slow method of removing nonviable tissue. Odor typically present and can increase risk of infection. (See Figures 16-18) 

Biosurgical Debridement (bottle fly larvae)

Biosurgical debridement, also known as sterile medical maggot therapy, involves placing live, sterile bottle fly larvae (Lucilia sericata) into chronic, necrotic wounds of the extremities. Maggots eat only necrotic tissue and will not harm healthy tissue. The question that is often asked is — How are the larvae sterilized? For clarification, they do not undergo miniature hysterectomies and vasectomies, but, rather, they are born (hatched) into a sterile environment before being placed into a wound. The maggots serve three basic functions: 1) debridement, 2) disinfection of the wound with biofilm inhibition, and 3) stimulation of wound improvement. Typically, there is no need to count the number of larvae that go into the wound bed or count the number that come out, although the recommendation is to apply 5-8 larvae per cm² of wound. Generally, they are left in place for 72 hours before removal and then discarded in a standard biohazard bag.^16,17 PROS: Cost-effective method of debridement that is very thorough and typically involves no pain. Does not remove viable tissue. Best performed in the inpatient setting to maintain control of maggots. CONS: Should only be used on extremities. Contraindicated in or near body cavities such as the abdomen and thorax or around necrotic blood vessels.¹⁶ Patients can have a negative psychological reaction due to the morbid nature of maggots eating their flesh. Larvae can escape the cage dressing and squirm into a patient’s bed or room. It takes two weeks for a maggot to transform into a fly under ideal circumstances, which should never happen in a controlled hospital setting. (See Figures 19-21) 

Enzymatic Debridement

Enzymatic debridement utilizes enzymes to degrade and remove necrotic tissue. These enzymes digest and dissolve necrotic tissue in the wound bed by breaking down collagen, elastin, and other parts of the devitalized wound matrix found within the wound bed. Most of these enzyme types have been removed from the commercial market, with the exception of those that target nonviable collagen known as collagenases. This enzymatic debridement selection, while targeting the nonviable collagen tissue, spares viable tissue, making it beneficial in necrotic wounds with slough in the base of the wound. Collagenase is derived from Clostridium histolyticum and is a prescription medicine. It is believed to upregulate the migration of keratinocytes over the wound bed and stimulate granulation development while it degrades nonviable tissue.^18,19 PROS: Safe and easy to use. Reduces scarring. Can be used in conjunction with routine surgical debridement. Pharmacy item that’s not considered durable medical equipment. Works faster than most autolytic options. Best when used in conjunction with weekly selective debridements. CONS: Very slow action. Cannot eliminate large amounts of necrotic tissue. Expensive when compared to autolytic debridement items. Not as effective as surgical debridement alone. Can be cost-prohibitive, depending on patient’s insurance. Clinicians sometimes rely solely on enzymatic debridement instead of aggressively excising necrotic tissue early in treatment course. Antimicrobial agents, such as silver and iodine, when used in conjunction with collagenase can decrease enzymatic debridement effectiveness. (See Figures 22-24) 

Wounds not to Debride

Ischemic wounds of the extremities prior to revascularization

It is common knowledge that ischemic wounds of the extremities with critically compromised blood flow should not be debrided until adequate revascularization has been achieved. However, what should be done with a foot wound that has been “maximally revascularized,” but still appears somewhat dry and it is unclear if there is still compromise? Post-revascularization microangiographic diagnostic studies are sometimes inconclusive, with transcutaneous oximetry readings or skin perfusion pressure values yielding borderline results. Many wound specialists would err on the side of caution and withhold debridement of necrotic extremity ulcers. However, if the wound fails to improve after several weeks, the authors would suggest another option: a “diagnostic debridement,” a term coined by the authors to describe a single debridement with the purpose of determining if a wound will respond positively or negatively to the procedure. The diagnostic aspect of this type of approach allows the wound specialist to determine if there is enough blood flow to heal the skin in that specific angiosome based on clinical observation post-debridement. If after one week post-debridement the wound appears to be improving, keep debriding. If the wound maintains a dry, nonviable status, paint daily with an antimicrobial solution (eg, povidine) and manage conservatively or refer for amputation, if appropriate.

“Dry, stable eschars of the heel without signs of edema, fluctuance, or drainage”

This old rule has become controversial, as a patient with adequate blood flow to the foot and heel can be carefully debrided with excellent results, especially if care is taken not to expose healthy calcaneal bone. Diagnostic debridement can be beneficial with this type of patient. After initial debridement of the eschar edges, if the wound worsens, discontinue further procedures. If the wound edges fill in with each debridement, continue weekly procedures until closure. (See Figures 25-27) 

Calciphylaxis

Debridement is contraindicated when there is expanding tissue necrosis with violaceous border. Once the patient has been successfully treated with sodium thiosulfate therapy and the necrosis expansion and violaceous border has subsided, the wound may be surgically debrided. The diagnostic debridement approach can be used with repeat procedures being performed only if the wound responds positively to the initial debridement.²⁰ (See Figures 28 and 29) 

Pyoderma gangrenosum

Debridement is contraindicated when there is a raised, active border. Once the patient has been successfully treated with immunosuppressive therapy and the raised, erythematous border has subsided, the wound may be surgically debrided.²¹ A diagnostic debridement can be used with repeat procedures being performed only if the wound responds positively to initial debridement. (See Figure 30) 

A Note on Inappropriate Sutures

Debriding and then suturing a chronic wound closed should never be done. This should not be confused with the delayed primary closure technique that surgeons use to close acute wounds, which has been proven to work quite well. Nonhealing, chronic wounds are stalled in the inflammatory phase of wound healing. Thus, suturing a chronically inflamed wound traps drainage and eventually leads to dehiscence, usually with infection.²² Debriding and suturing chronic wounds closed without wide excision to get to fresh viable tissue rarely works, if ever. (See Figures 31-33) 

Conclusion

Definitively knowing which debridement modality to use and how often to debride when it comes to certain types of wounds is critical for any wound care clinician and will always be a challenge because each clinician has a different comfort level regarding aggressive debridement. With all the questions surrounding debridement, however, one thing is clear: inadequate debridement delays wound healing and patients become less forgiving the more time it takes to heal. Luckily, today’s wound care specialists have more “weapons” to choose from than ever before. Maximizing each modality, whether alone or in combination, is the key to winning each fight in the battle against the 6 million chronic wounds affecting patients in this country.²³ 

Shaun Carpenter is chief executive officer and co-founder of MedCentris,^TM a multi-specialty practice group based in Hammond, LA, that focuses on wound healing and limb salvage. He is also the inventor of the Carpenter Curette,^TM a surgical instrument used to debride necrotic wounds. Todd Shaffett is president and co-founder of MedCentris and co-founder of Healtec,^TM an advanced medical device company.

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