Version May 2024
INTRODUCTION — Necrotizing soft tissue infections (NSTIs) are the most severe among the spectrum of skin and soft tissue infections, including surgical site infections (table 1 and table 2) [1-3]. The presentation is variable with respect to the etiology, anatomic location, and extent of required initial and subsequent debridement, and the manner and complexity of reconstruction. NSTI may involve any or all layers of the skin and soft tissue, including dermis, subcutaneous fat, fascia, and muscle, as well as other structures.
NSTI is challenging to manage successfully because of the rapid onset and extent of the disease process, which is frequently underestimated at initial presentation. Prompt recognition and adequate initial surgical debridement, preferably at the institution to which the patient presented, reduces morbidity and improves survival [4,5]. Thereafter, an interhospital transfer may be required for optimal care, which often requires further aggressive debridement and supportive critical care, sometimes followed by a prolonged and complex process of reconstruction and rehabilitation to regain form and function. Patients with NSTI are best cared for at tertiary/quaternary care facilities that can provide a multidisciplinary team approach to managing their complex care [6-8]. Burn centers can offer such a multidisciplinary approach by having access to the operating room, isolation rooms and rigorous infection control practices, critical care, and wound care resources, in addition to a team of staff from a variety of backgrounds with the knowledge, skills, and interest to care for these patients.
The operative management and perioperative care of patients with NSTI are reviewed here. The risk factors, clinical features, microbiology, diagnosis, and antimicrobial treatment of NSTI are discussed separately. (See "Necrotizing soft tissue infections".)
SURGICAL EXPLORATION — Whenever a diagnosis of NSTI is suspected (sepsis, rapid deterioration in clinical condition, necrosis, bullae, or crepitus of the skin) [9], surgical exploration is indicated to perform debridement to the extent that is deemed necessary based upon the appearance of the tissues, or to confirm the diagnosis, if it remains in question (algorithm 1).
Surgery indicated for clinical suspicion — Although patients with NSTI may appear quite well during the early part of their clinical course, deterioration within hours of presentation frequently occurs, with the infection having the potential to cause extensive soft tissue necrosis (picture 1). As such, a suspicion of NSTI is all that is required to prompt surgical exploration, particularly in high-risk patients (eg, immunocompromised, diabetic, or postsurgical patients) [3,4,10,11]. Although such high-risk individuals comprise the majority, some of the most severe cases of NSTI have occurred in young patients with no obvious predisposing factors. Occasionally, a history of upper respiratory tract infection or minor skin infection prior to an inciting trauma may be elicited, but often no such history is forthcoming. (See "Necrotizing soft tissue infections", section on 'Risk factors'.)
Timing of initial debridement — Failure to recognize the severity of the disease delays the initial debridement, in turn delaying transfer for definitive care. Delays in surgical treatment correlate with worse outcomes and higher mortality rates. Thus, surgical source control should be achieved promptly [3,12-22]. In one review, the only variables that consistently correlated with higher mortality were age and debridement after 24 hours of admission [23]. In a study that used the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score to assist with the diagnosis of NSTI, a 24-hour delay in debridement resulted in a ninefold increase in mortality [24]. Although, a low LRINEC score is likely not sufficient to rule out a diagnosis of NSTI [25]. In a systematic review that included 2123 patients, the mortality rate was lower for those receiving surgery within six hours compared with later (19 versus 32 percent) after six hours of presentation. However, in the lower extremity, time-related presentation variables did not appear to influence amputation rates [22]. In another study, delays resulted in longer hospital stays [26].
It is important to keep in mind the variability that exists in what is meant in the literature by "early intervention." Some studies have used time of diagnosis, while others from the onset of symptoms, presentation, or hospital admission [15,16,24,27].
Optimal facility for initial debridement — Based upon observational data, we suggest that patients should undergo initial debridement at the facility to which they first presented and where the diagnosis is first suspected to more rapidly achieve infection source control, provided an appropriately experienced surgeon is immediately available to perform the procedure. Although the immediate transfer to a center accustomed to managing severe soft tissue infections or injuries may seem appropriate, in a large observational study of 9958 patients, those debrided initially at the hospital to which they presented had a significantly reduced incidence of death compared with those transferred without debridement (15.5 versus 8.7 percent) [28].
Once the initial debridement has been performed, referral should ideally be initiated to a tertiary/quaternary care institution with a multidisciplinary environment accustomed to managing complex wounds of this nature and extent for further debridement, subsequent soft tissue reconstruction, and rehabilitation. Burn centers can be considered an optimal location for the provision of such care, as they are accustomed to managing patients with extensive soft tissue wounds [6-8,18,29,30]. Despite some studies demonstrating longer hospital lengths of stay and higher costs at burn centers, it is important to note that patients who are transferred are fundamentally different from those who are not transferred (more severe infection, uninsured) and that more than one-half of patients with NSTI managed in a burn center have been transferred from other hospitals [7].
Surgical specialty consultation — Because NSTI may involve any anatomic region, a referral protocol should be established so that the most appropriate surgeon available performs the initial debridement [30]. That being said, despite the trend toward surgical subspecialization, soft tissue debridement remains a fundamental surgical skill, and given the need for prompt surgical debridement, general surgeons are frequently called upon to undertake the initial debridement of NSTI [31].
The extremities are the most frequently involved site of infection (58 percent), followed by the trunk (26 percent) and perineum (40 percent; incorporating the subgroup of Fournier gangrene) [29,32], but the head and neck, the periorbital region [33], and the hands can also be involved. Surgeons who are well acquainted with the anatomy of these individual regions should ideally perform these initial and subsequent debridements.
GENERAL PREPARATION
Patient optimization — The patient's physiological condition should be optimized prior to surgery, without causing a delay in the timing of the initial debridement. This generally occurs in an intensive care unit setting, where aggressive fluid resuscitation and inotropic/vasoactive support might be required for patients with sepsis. Infection with group A Streptococcus infection is more often associated with septic shock requiring treatment with inotropes/vasopressors. Critical to successful outcomes is an unambiguous and seamless line of communication between the surgeon and the intensivist, particularly with respect to the timing of surgical interventions, and consistent and effective discussions with family or other caregivers.
For critically ill patients, central venous access and an arterial line should be obtained, and a Foley catheter and an enteral feeding tube should be inserted. Endotracheal intubation and mechanical ventilation are often necessary.
An anesthetist should be consulted to assess the patient and prepare for anesthesia. Occasionally, regional anesthesia is an option; however, general anesthesia is preferred given the presence of infection, and the often underestimated extent of disease. Blood for type and crossmatch should be obtained and blood products should be available. The anesthetist will also have determined to which of the six physical status categories of the American Society of Anesthesiologists (ASA) the patient belongs (table 3); NSTI usually falls into at least a "3E" category (severe systemic disease) but is often a "5E" (a moribund person who is not expected to survive without surgery) [34]. "E" denotes that the surgical intervention is an emergency.
Antibiotics — Empiric antimicrobial therapy should be initiated, if not already started, re-dosed intraoperatively, as determined by the length of the procedure, and continued postoperatively until the responsible organism(s) are determined from debridement specimens (algorithm 1). Ongoing empiric therapy should cover both gram-negative and gram-positive organisms, including methicillin-resistant Staphylococcus aureus (table 4), combined with an anti-ribosomal agent (eg, clindamycin) to cover gram-positive organisms potentiating rapidly progressive NSTI via exotoxin production. Definitive treatment should be tailored to Gram stain, culture, and sensitivity results, when they become available. In addition, information from a study that has demonstrated geographic regionality to the causative organisms of NSTI may help with the initiation of empiric antimicrobial therapy [35]. Specific empiric antimicrobial regimens and potential pathogens are reviewed separately. (See "Necrotizing soft tissue infections", section on 'Antibiotic therapy' and "Necrotizing soft tissue infections", section on 'Conditions, microbiology, and epidemiology'.)
Informed consent — Informed consent should be obtained from the patient, if possible, and a focused discussion that may include family or other caregivers should review the urgency and purpose of the initial extensive surgical debridement as well as the possibility for adjunctive procedures. If not already done, a proxy should be established since the patient may not be in a position to make decisions regarding ongoing care [36,37]. Discussions regarding advanced care directives may also need to be initiated at this stage, given the significant morbidity and mortality associated with this condition. (See "Informed procedural consent".)
The intraoperative assessment is often more severe than the preoperative one, and so the possibility that additional procedures will be needed should be discussed. A realistic impression of the patient's prognosis should be conveyed to the patient and their family or other caregivers. Although major amputation for extremity NSTI is seldom indicated in the primary operation, should this be deemed necessary, either during the initial assessment or during surgery, this should be discussed during the consent process. Extensive abdominal NSTI may also warrant the creation of a stoma or an "open abdomen" at the conclusion of surgery, and these possibilities should also be discussed in advance. If a particular course of treatment was not able to be conveyed preoperatively, sometimes it might be possible for one of the surgeons to exit the operating room to discuss a change in operative plan with the proxy decision maker should these become necessary, provided that this delay would not compromise the prompt execution of life-saving surgery.
Regular detailed explanations will also be required before and after subsequent operations.
SURGERY — Anticipated requirements for patient positioning (eg, lithotomy, supine, prone, lateral decubitus), which depend upon the anatomic location of NSTI, should be discussed with the operating room staff and appropriate preparations made. The operating room should be warmed to 30°C prior to the patient entering the room, particularly if large surface areas will need to be exposed, or if the patient is physiologically unstable. Hypothermia will exacerbate coagulopathy and blood loss and compromise intraoperative and postoperative care, regardless of the benefit obtained from a thorough debridement. We suggest routine use of preoperative warming blankets using forced air, which ameliorates the inevitable drop in temperature during induction of anaesthesia and during preparation and draping [38].
Once in the operating room, all members of the team, including nursing staff, anesthetists, and surgeons, should participate in a World Health Organization "surgical safety checklist," which is an obligatory pause in proceedings that allows the entire team to discuss the extent and details of the patient's condition, allergies, antibiotic requirements, specimens to be sent for microbiological or histologic examination, surgical equipment, and dressings [39]. Communication of this nature will prevent unnecessary delays in the execution of the surgery, which could compromise patient care.
Surgical preparation and draping should be performed in a similar manner as with any elective clean surgery. We use 4% chlorhexidine soap followed by 7.5% povidone iodine soap and 10% povidone iodine solution. (See "Overview of control measures for prevention of surgical site infection in adults", section on 'Skin antisepsis'.)
Limited exploration for equivocal cases — For patients in whom the clinical diagnosis of NSTI is less convincing, a small skin incision can be made and carried down to the fascia (algorithm 1). With established "necrotizing fasciitis," the involved fascia is often not adherent to the overlying adjoining layers (picture 2), allowing the surgeon to easily dissect with his or her finger along the fascial plane. Local exploration also allows examination of underlying fat and muscle [3,18]. However, while loss of tissue adherence is a sensitive sign for the entity necrotizing fasciitis, it may not be present early on and does not apply to all entities within the classification of necrotizing soft tissue infections. In addition, despite the findings of a negative exploration, surgeons need to be vigilant until signs of improvement, as some of those patients with initial negative findings on exploration will progress to NSTI [40].
Debridement procedure — The initial skin incision is usually made to include all overtly necrotic skin. If there is no necrotic skin, then the incision is made over the area deemed to be the center of the disease process, similar to the drainage of an abscess. Obviously, the etiology of the NSTI may dictate the specific approach, as might be relevant in a case of incisional NSTI or specific anatomical location. In general, a circular pattern of debridement is advocated, starting at the most severely involved region and progressively outwards until healthy soft tissue is encountered [18]. No consideration for the subsequent reconstruction should be given, as doing so might compromise a thorough surgical debridement. The incidence of septic shock and renal failure and the likelihood of death all increase with incomplete initial debridement.
In contemporary studies, there have been advocates for a more conservative approach, with greater emphasis on preserving all skin unless obviously involved. If successful, this strategy may reduce the need for skin grafting and more sophisticated skin coverage techniques [41] but may also necessitate more frequent visits to the operating room and more vigilant observation. Our practice has generally been more aggressive during the early stages, based on the belief that the NSTI often extends well beyond what is initially observed externally (picture 2) and that delays may compromise patient survival.
Initial debridement of necrotic tissue is undertaken most rapidly and effectively using a #10 scalpel blade and large curved Mayo scissors for large areas, or a #15 blade and Metzenbaum scissors for more specialized areas such as the face and hands. Thrombosis of the underlying dermal capillary network precedes overt skin necrosis, and during debridement, incision through the involved areas will not bleed normally. The debridement should extend beyond this into healthy tissue until normal bleeding is seen. The margin and depth of the wound should be thoroughly explored to ensure that there are no areas of extension of the infection. In certain cases, exploring deep to the fascia between muscle planes may be needed to achieve source control. Exposing muscle need not complicate reconstruction.
During the course of debridement, multiple tissue biopsies and cultures should be obtained from several sites, labeled, and sent for microbiological and histologic evaluation to confirm the responsible organism(s) involved and guide antibiotic coverage and antimicrobial dressings. Characteristic histologic findings include subcutaneous necrosis, polymorphonuclear cell infiltration, fibrinous vascular thrombosis, and microorganisms within the destroyed fascia and dermis. Gram stain and histologic examination should be performed early and may identify other possible infective organisms (eg, gram-positive bacilli, fungal filaments, or spores) that may influence initial antimicrobial coverage. Some have advocated for examination of a frozen section of a tissue biopsy to assist with early diagnosis, but in our experience, this is impractical and needlessly time consuming [42,43].
The wound should be repeatedly and copiously irrigated with a broad-spectrum antiseptic solution, such as sodium hypochlorite 0.025% (1:20 Dakin solution [ie, 0.5% sodium hypochlorite] diluted in sterile water or saline) [44]. A hydrosurgery system (picture 3) (eg, Versajet, based on the Venturi effect) can be used to remove debris and reduce bioburden, particularly in subsequent debridement [18]. The console settings should initially be low (level 2 through 5) to avoid undue tissue injury [45].
At the initial and each subsequent debridement, specimens at the margins of the wound should also be sent for pathologic examination to confirm that the histologic and microbiologic findings correspond to the intraoperative assessment that all necrotic and infected tissue has been removed. Tissue that appears normal often demonstrates extensive vascular thrombosis when examined microscopically, which has a high potential for full-thickness loss. It is for this reason that radical debridement is justified, particularly if bleeding from the tissue surfaces is noted to be sluggish.
Thorough hemostasis should then be undertaken making use of electrocautery. The injection of diluted epinephrine is best avoided in this context, in spite of its utility in burn surgery for reducing blood loss. Epinephrine injection can cause delay in achieving source control and facilitate extension of infection along fascial planes, or indeed potentially compromise the interpretation of tissue viability. If needed, we use dilute topical epinephrine applied with the same Telfa pads used for topical antiseptic solutions and hydrogen peroxide.
Once the debridement is completed, an antiseptic dressing should be applied. We use an initial dressing of povidone iodine or sodium hypochlorite 0.025% (1:20 Dakin solution [ie, 0.5% sodium hypochlorite] diluted in sterile water or saline), covered by absorptive layers of gauze secured in place. An interface or nonadherent layer may be required over more sensitive structures, but given the plan for an operating room relook, this is generally not indicated. (See 'Wound care' below.)
The patient is returned to the intensive care unit for ongoing care, antibiotics, fluid therapy, and nutritional support. (See 'Perioperative care' below.)
Documentation and medical photography — At the time of the initial debridement, and at each subsequent surgery and dressing change, the following should be accurately documented: the specific location of the wound; its dimensions; the appearance of the wound base, edges, and surrounding skin; all involved and adjacent structures; and the presence of any undermining or tracts. In addition to written descriptions and sketches, medical photography is helpful to record the wound extent and progression at each surgical intervention, to help plan reconstruction, and for teaching, medicolegal, and research purposes [18]. Consent should be obtained to take and securely store medical photographs.
Adjunctive procedures — Unique challenges to surgical therapy and subsequent reconstruction arise depending on the location of the NSTI.
Fecal diversion — A number of cases of NSTI involve the perianal or perineal region. Some patients benefit from a diverting colostomy to reduce the risk of secondary wound contamination with enteric bacteria. For maximal benefit, colostomy should be performed early in the surgical course. Preoperative discussions should identify the preferred location of the stoma, method of creation (laparoscopic or open), and likely timing of reversal [46,47]. (See "Overview of surgical ostomy for fecal diversion".)
A less invasive but highly effective strategy for cases near the anal verge is to insert a rectal diversion device. An example is a silicone catheter with an inflatable balloon and irrigation port (eg, Flexi-Seal) (picture 4). While generally effective, these can leak or occlude, thus requiring the stool to be loose for optimal functioning [46,47]. Effective application of a bowel regime or protocol of stool softening medications may be needed, especially since that these patients are usually receiving infusions of opiates and other constipating medications. Complications such as rectal erosion and bleeding are known to occur as a result of using these devices, and their indications and efficacy should be regularly reviewed.
Amputation — A decision for amputation is not taken lightly and should ideally be corroborated by another expert. (See "Surgical reconstruction of the lower extremity", section on 'Limb salvage versus amputation' and "Surgical reconstruction of the upper extremity".)
Primary amputation may be the more expeditious and potentially life-saving intervention for some patients, reducing operative time and blood loss compared with successive debridements [48-51]. Amputation may also be considered if repeated debridements are unlikely to obtain source control, when functional outcomes are likely to be obviously better with an amputation compared with a reconstruction, or when no reconstructive options exists.
Between 10 and 20 percent of patients with NSTI may require an amputation [52]. Amputations are more frequently indicated for critically ill patients with diabetes or underlying peripheral artery disease, but group A Streptococcus infection alone may lead to overwhelming tissue destruction necessitating amputation. (See "Invasive group A streptococcal infection and toxic shock syndrome: Treatment and prevention", section on 'Surgical debridement'.)
When performed as an emergency, particularly in an unstable patient, a "guillotine" amputation should be performed to remove skin, soft tissue, and bone expeditiously at an uninvolved level proximal to the NSTI. No effort is made to design flaps to cover the bone, and the bone may need to be shortened subsequently to facilitate definitive closure. (See "Techniques for lower extremity amputation" and "Upper extremity amputation".)
PERIOPERATIVE CARE
Second-look surgery and subsequent debridement — An obligatory second-look surgery in the operating room should be scheduled and undertaken within 24 hours after the initial debridement. Physiologic deterioration within that time frame may necessitate earlier intervention. On average, three to four debridements will be needed, though more than this has been reported, before definitive reconstruction can be initiated [18,30,32].
Laboratory markers of infection may indicate the need for earlier or repeat debridement. In addition to standard bloodwork and regular clinical evaluation, at least one, but preferably two, of C-reactive protein (CRP), lactate, or procalcitonin (PCT) levels should be obtained every six to eight hours and compared to baseline values to assist in this evaluation. Although there is limited experience using these biomarkers in the specific context of NSTI, these have been used to judge the severity of other infections. Among the biomarkers available, PCT appears to more closely correlate with the severity of infection and consequent organ dysfunction [53,54]. PCT also helps guide the appropriate duration of antimicrobial therapy. (See "Evaluation and management of suspected sepsis and septic shock in adults", section on 'Septic focus identification and source control'.)
Wound care
Dressings — The aim of appropriate wound dressings is to provide an optimal environment for wound healing. Antiseptic dressings play an important role in complementing the surgical debridement [55]. (See "Basic principles of wound management" and "Topical agents and dressings for local burn wound care".)
Wound dressings, particularly those later in the management course, should be applied with physiotherapy in mind. Dressings that limit mobility should be avoided as they may promote the development of contractures or deformities. This is particularly important to consider when the hand or the major joints of the upper and lower extremities or the neck are involved. Negative pressure wound therapy (NPWT) has proved to be an excellent dressing facilitating the ability of the patient to move around with a secure, less bulky dressing. (See 'Negative pressure wound therapy' below and 'Rehabilitation' below.)
Topical antimicrobial dressings — In spite of surgical debridement, microbial pathogens will still be present in the wound forming biofilm, which will contribute to delayed wound healing. Antimicrobial dressings are often used to minimize the burden of microbes in the wound and mitigate these effects.
Microbes delay wound healing by producing inflammatory mediators and metabolic toxins and by maintaining an activated local and systemic neutrophil population, which in turn produces cytolytic enzymes and free oxygen radicals. This prolonged inflammatory response contributes to further host injury. Bacteria also compete with host cells for nutrients and oxygen, contributing to tissue hypoxia. Wound contamination also renders newly formed granulation tissue hemorrhagic and fragile, reduces fibroblast number and collagen production, and impairs re-epithelialization.
Available topical antimicrobials for reducing bioburden and surface contamination when treating NSTI include sodium hypochlorite 0.025% (1:20 Dakin solution [ie, 0.5% sodium hypochlorite] diluted in sterile water or saline), polyhexamethylene biguanide (PHMB)/betaine (ie, Prontosan), povidone iodine, acetic acid, mafenide acetate, and various silver-containing dressings. Among the available listed, when dressing changes will be frequent, we favor alternating sodium hypochlorite 0.025% (1:20 Dakin solution [ie, 0.5% sodium hypochlorite] diluted in sterile water or saline) and PHMB/betaine (ie, Prontosan) as an antiseptic soak (in certain cases this may be applied using negative pressure wound therapy). Mafenide acetate or povidone iodine solution are alternative topical antiseptic solutions [6]. Silver dressings and NPWT may be used during the later stages as dressing frequency reduces. (See "Topical agents and dressings for local burn wound care", section on 'Antimicrobial agents' and 'Negative pressure wound therapy' below.)
The choice of topical antiseptic agent is influenced by its biocompatibility (antiseptic efficacy relative to its cytotoxicity). Although effective, most topical antimicrobial agents have negative cytotoxic effects on normal and healing cells [56,57]. Cell microcirculation is also impaired by many of these dressings, resulting in disordered blood vessel leakage, capillary functional densities, and red cell velocity, which may again have a profound impact on wound healing [58].
●Dakin solution (0.5% sodium hypochlorite) at even one-quarter strength is unnecessarily cytotoxic. Thus, we use a dilute concentration (sodium hypochlorite 0.025%) that is at least 20 times lower than the standard solution [44]. An alternative agent, hypochlorous acid, has a similar spectrum of activity and can be obtained commercially rather than mixed in the pharmacy to the desired concentration.
●PHMB/betaine (ie, Prontosan), which has excellent efficacy and minimal cytotoxicity [59], is available as a wound gel or wound irrigation (often used with NPWT). PHMB is similar to naturally occurring broad-spectrum antimicrobial peptides that are able to disrupt the lipopolysaccharide layer of the bacterial cell wall, with minimal effect on the neutral lipids in human cell membranes. Betaine is a surfactant, which facilitates effective irrigation, while also disrupting biofilm colonies by interfering with homoserine lactone manufacture.
●Silver dressings remain integral to the management of NSTI wounds. One of the favored silver dressings is a nanocrystalline silver product that releases Ag1+ ion (ie, Acticoat) in a controlled manner, permitting dressing change intervals up to 72 hours. We therefore use Acticoat later in the course of treatment when greater intervals between dressing changes are possible. Resistance to nanocrystalline silver has not been described, probably due to the multipronged mechanisms of action, which include the inhibition of electron transport system/respiratory chain in bacteria, the interaction and rupture of the cell membrane and cell wall, and the interference with bacterial cell deoxyribonucleic acid [60,61].
Negative pressure wound therapy — Negative pressure wound therapy (NPWT), also called vacuum-assisted wound closure, refers to wound dressing systems that continuously or intermittently apply subatmospheric pressure to a filler substance (foam or gauze) placed on the surface of a wound. (See "Negative pressure wound therapy".)
NPWT is an important wound care strategy for optimizing outcomes in patients with NSTI. NPWT maintains a moist, closed-wound environment, manages excess exudate, and helps to prepare a wound bed for skin grafts or tissue flaps by stimulating the formation of granulation tissue. Due to the constant uniform positive pressure applied to the wound bed, NPWT is also an excellent bolster over skin grafts [62-67]. The benefits of NPWT have been augmented by the ability to irrigate the wound through these systems, which may reduce the number of operations and pain, as well as limiting wound desiccation and trauma. A preset volume of fluid can be automatically delivered via the tubing and held in the foam to bathe the wound for a predetermined time, after which negative pressure is again applied to drain the irrigation fluid and any wound exudate from the foam into the canister [62-68]. The cycle continues automatically, and the fluid, system settings, and duration of therapy can be adjusted according to the clinical indication.
After the initial debridement, subsequent debridement is undertaken with greater intervals between surgeries, and once the dressing changes are more than 48 hours apart, NPWT can be applied for ongoing antisepsis and wound bed preparation [68-70]. Cases vary in terms of the extent of disease and structures involved, which influences the ease of application of NPWT (picture 5). In some cases of limited soft tissue loss, NPWT may be considered earlier in the postoperative course provided a reliable seal can be obtained and the NPWT dressing can be easily and rapidly changed. Decisions may also be influenced by the availability of operating time, surgical staff, and clinical load, although NPWT may be exchanged effectively under sedation in a monitored setting (critical care unit, or step-down unit). Many surgeons prefer a simple antiseptic soak initially (eg, sodium hypochlorite 0.025% [1:20 Dakin solution (ie, 0.5% sodium hypochlorite)] diluted in sterile water or saline) until source control is obtained [3].
Given its tremendous benefit, advocates of NPWT have adapted the use of the device to the various challenges that arise in the context of NSTI. These include methods of obtaining a reliable seal around the perianal and perineal region, around a stoma or on an open abdomen, around a urinary catheter or fecal diversion device, or in the head and neck region. This has necessitated the use of different fillers, including foams and gauzes; various interfaces; modalities such as continuous, variable, or intermittent settings; and various products to improve adherence of the adhesive film, such as tincture of Benzoin, stoma pastes, and adhesive double-sided hydrogel patches (picture 6) [66,67].
Hyperbaric oxygen — The evidence for hyperbaric oxygen (HBO) has been contradictory as there may be benefit in terms of limb salvage for selected patients after the initial surgical debridement. It is likely, however, that transfer to another facility that offers HBO may compromise, rather than improve, patient outcomes during the initial perioperative period [71-73]. (See "Hyperbaric oxygen therapy".)
Pain management — Given the nature and extent of the initial and subsequent debridement and later reconstructive procedures, patients with NSTIs experience considerable pain and anxiety. Inadequate attention to pain significantly impairs physical and psychosocial rehabilitation and increases the risk for allodynia or hyperalgesia. Frequent evaluations and assessments are required, and strategies should be regularly adjusted to the phase of care and interventions.
The nursing staff play a critical role by triaging patient concerns and considerations to other members of the team and documenting the efficacy of interventions. Self-reported systems such as the visual analog scale, Faces Pain Scale, or the numeric rating scale should be used for the assessment of pain. A dedicated pain service may coordinate more advanced strategies, such as regional nerve blocks and patient-administered intravenous analgesia perioperatively, as well as being responsible for adjusting standard analgesia and adjuncts in selected patients.
Both pharmacologic and nonpharmacologic therapies are indicated. The agent chosen and route of administration depend on the type of pain as well as the stage of the patient's care, whether acute, reconstructive, or rehabilitation. Most patients with NSTI require multiple agents to optimally manage their pain, and secondary agents may offer an opiate-sparing effect. Gabapentinoids (gabapentin, pregabalin) are useful adjuncts for managing neuropathic pain symptoms and have been shown to reduce the incidence of hyperalgesia. In addition, pregabalin has a better side effect profile and can also enhance mood [18,74]. (See "Management of burn wound pain and itching" and "Approach to the management of acute pain in adults".)
Patients with NSTI experience three types of pain, namely background pain, breakthrough pain, and procedural pain. (See "Paradigm-based treatment approaches for management of burn pain".)
●Background pain may be a relatively consistent underlying ache, mild to moderate in severity, optimally managed using long-acting narcotic agents such as hydromorphone controlled release (Hydromorph Contin; between 3 and 15 mg three times a day), and regular simple adjuncts such as acetaminophen and nonsteroidal anti-inflammatory drugs, if no contraindication exists.
●Breakthrough pain is an exacerbation of pain stimulated by therapy, emotion, or simple movement in bed. Short-acting opiates such as hydromorphone intravenously or orally are appropriate for this indication.
●Procedural pain occurs as a result of surgical procedures, physiotherapy, or dressing changes and can manifest in considerable anxiety in addition to acute and severe pain. A short-acting anxiolytic such as midazolam or lorazepam, in addition to a short-acting intravenous opiate such as fentanyl or hydromorphone, is best suited to address this pain. Deep or conscious sedation may be administered to facilitate major dressing changes. This allays much of the anxiety or anticipatory pain associated with the procedure itself, is safe if protocols are adhered to, and reduces the development or exacerbation of complex pain syndromes. We usually make use of ketamine, fentanyl, and midazolam for this purpose, titrated to effect, in a monitored setting including continuous measure of blood pressure, pulse rate, pulse oximetry, and end tidal carbon dioxide. There is a growing body of literature supporting the value of virtual reality as a distraction to reduce the perception of pain and to address anxiety during major dressing changes [75,76]. (See "Procedural sedation in adults in the emergency department: General considerations, preparation, monitoring, and mitigating complications".)
Nutritional support — Every patient with NSTI should undergo a complete nutritional assessment to determine the appropriate volume, route, and type of nutritional support needed [77,78]. Nutritional support is generally administered based on surface area involved, resting energy expenditure, and baseline nutritional assessment (algorithm 2). (See "Overview of nutrition support in burn patients".)
Underfeeding can occur when patients are kept nil per os for prolonged periods of time before and after their frequent surgical procedures or other interventions. Malnutrition is to be avoided as it diminishes fibroblast proliferation, impairs neovascularization, and decreases immunity. A volume-based feeding protocol should be instituted to compensate for periods of time when food will be withheld. It is not necessary to hold tube feedings in intubated patients who will be undergoing surgery, and feeding should ideally continue intraoperatively.
RECONSTRUCTIVE SURGERY — Once additional surgical debridement is no longer necessary, wound coverage and closure are the next goals. No definitive coverage should be undertaken until all necrotic areas have been debrided and the patient is physiologically stable. This often corresponds to the observation of healthy granulation tissue in the wound bed. Temporary deceased donor allograft skin coverage may be applied at this stage as it will reduce heat and evaporative fluid losses and reduce the inflammatory and hypermetabolic stimuli caused by the open wound. This allows a timeframe during which the patient can further recover physiologically. Most cases of NSTI are amenable to split-thickness skin autografting to obtain durable coverage. Depending upon the location of the infection, some patients may require regional muscle or fasciocutaneous flap to cover exposed bony surfaces, tendons, or neurovascular structures [79]. (See "Skin substitutes" and "Skin autografting" and "Overview of surgical procedures used in the management of burn injuries".)
Skin coverage — As previously mentioned, the application of deceased donor allograft skin is an important temporizing strategy. Prior to committing donor sites for definitive autograft coverage, the allograft can be used as an effective means of evaluating wound bed preparation. (See "Skin autografting" and "Skin substitutes".)
If the allograft adheres, it is reasonable to assume that the autograft will be similarly effective [80,81]. Once allografting is successful, definitive coverage is not urgent and may be delayed as long as two to three weeks before the allograft is rejected. During this period, optimizing nutrition and rehabilitative strategies should be prioritized. Allografting also provides time for the multidisciplinary team to develop a reconstructive strategy that will provide the best functional and aesthetic outcomes.
For definitive reconstruction, most cases of NSTI are amenable to split-thickness autografting (picture 6). Some patients may require regional muscle or fasciocutaneous flap to cover exposed bony surfaces (picture 7), tendons, or neurovascular structures. Muscle flaps are often favored over fasciocutaneous flaps for their ability to optimally conform to defects, their predictable pattern of blood supply, and also to deliver potentially improved blood supply to an area [82]. However, fasciocutaneous flaps are more durable and should be favored when covering pressure prone areas such as the elbow, sacrum, or ischial tuberosity. Microsurgical free tissue transfers are seldom indicated but may offer additional versatility and improved outcomes in selected cases. A systematic reviewed the use of flaps for coverage after debridements for NSTI [83]. Of these, more than half were for treatment of Fournier gangrene. Overall, the most common regional flaps used were gracilis muscle (picture 8), antero-lateral thigh, and various medial thigh perforator flaps. A minority of cases were free flaps, such as the latissimus dorsi flap for extremity reconstruction. (See "Flap reconstruction of the lower extremity".)
Selected cases may also benefit from the use of dermal substitutes, although these are generally avoided during the acute phase given the increased likelihood of infection complicating their successful application. Advocates maintain that dermal substitutes offer improved skin durability, laxity, and contour and may avoid the need for flap surgery. Excellent results have been described for one-stage epithelial coverage of dermal substitutes (eg, Matriderm). Other products (eg, Integra) possess a bilayer matrix wound dressing composed of a silicone outer layer over a collagen-based dermal analogue, requiring two to three weeks for integration and the separation of the outer layer before skin grafting. After the application of bilayer dermal substitutes, the patient's native fibroblasts, macrophages, and lymphocytes infiltrate, and there is new capillary growth in the matrix of the inner layer [84-86]. The inner layer becomes degraded, and an endogenous collagen matrix is deposited by the patient's fibroblasts, forming a neodermis.
Reconstructive revisions are occasionally required months or years after wound healing. This may entail contracture releases or scar revisions with local flaps, for example, or resurfacing procedures, to improve function, form, or both. Tissue expansion may also be used to create robust fasciocutaneous local flaps to resurface large adjacent areas.
Perineal reconstruction — Fournier gangrene and severe cases of NSTI of the perineum present unique reconstructive challenges (picture 4). The viability of the testicles is usually not threatened by the NSTI, and, depending on the extent of scrotal involvement, the testicles may already have been buried in medial thigh pockets.
Several reconstructive techniques are described in the literature, including residual scrotal skin mobilization and advancement, skin grafts, and pedicled or free flaps. Pedicled gracilis muscle flaps, pudendal artery perforator thigh flaps, and random flaps are some of the more frequently used options for perineal reconstruction, resulting in satisfactory outcomes with minimal morbidity [87-96].
REHABILITATION — Patients with NSTI have longer hospital stays than burn patients for the same body surface area involvement, often sustain more complex soft tissue defects, and, among those with extremity involvement, are more likely to have required an amputation. It is clear that those recovering from NSTI and its treatment benefit from the same multidisciplinary psychosocial and rehabilitative resources that enable burn survivors to reintegrate successfully into society.
NSTI has an enormous impact on the lives of survivors, their families, and patients' ability to interact with society. Better psychosocial adjustment correlates with increasing duration of follow-up and older patient age [97-101]. The social worker plays an integral role beginning in the early perioperative period with tasks that include liaising with members of the team to facilitate the seamless transition between different phases of care; contributing to optimal communication between the patient, the family or other caregivers, and the medical team; and accessing available financial and other forms of assistance for both patient and caregivers during and after the therapeutic process.
Dedicated physiotherapists and occupational therapists have a fundamental role in the multidisciplinary management of NSTI and should be involved from the onset of the therapeutic process, ameliorating the deconditioning associated with prolonged bedrest and critical illness. Close liaison with the surgeon and nursing staff is important to ensure that appropriate dressings and splints that facilitate physical activity are used. Specific programs are designed depending on the age and comorbidities of the patient, the patient's functional level prior to the NSTI, the specific stage of surgical intervention, and the severity and location of the NSTI. A number of therapies can be used, including strength and flexibility training, splinting, scar massage and moisturizing, pressure garments, and specific exercises to perform activities of daily life. Physical limitations and energy levels improve more slowly over time for older compared with younger patients.
MORBIDITY AND MORTALITY — Mortality rates attributed to confirmed cases of NSTI range from 9 to as high as 25 percent [23,102-105]. Data from the National Surgery Quality Improvement Program suggest that the mortality rate in the United States is less than 20 percent [97]. This compared favorably to a pooled analysis from the 1990s that reported a mean rate of 34 percent [52]. Immunocompromised individuals, who are more susceptible to NSTI and who frequently present late and have higher mortality rates compared with other patients with the condition [3,18,106]. In a systematic review including 6051 patients, mortality has been unchanged at about 20 percent over the past two decades [22].
A calculator for predicting the risk of death in patients with NSTI has been developed [107], although independent predictors and clinical scores have been previously validated [9,108-110]. Important factors include patient age >50 years, heart rate >110, body temperature <36.8°C, white blood cell count >40,000 mcL, serum creatinine >1.5 mg/dL, and hematocrit >50 percent. In another study, of 4597 patients with NSTI, older age, BMI under 18.5, sepsis at admission, dialysis, pre-existing diagnosis of cancer, and medications for MRSA infection were associated with higher mortality [111]. The presence of cancer, liver, and kidney disease were associated with higher mortality and higher chance of discharge to skilled nursing facilities in a series of older adult patients with NSTI [112].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Skin and soft tissue infections".)
SUMMARY AND RECOMMENDATIONS
●Necrotizing soft tissue infections – Necrotizing soft tissue infections (NSTIs) are the most severe among the spectrum of skin and soft tissue infections. Mortality in the United States attributed to confirmed cases of NSTI is approximately 20 percent. The presentation is variable with respect to the etiology, anatomic location, and extent of required initial and subsequent debridement, and the manner and complexity of reconstruction. The extent of the disease is frequently underestimated at initial presentation. NSTI may involve any or all layers of the skin and soft tissue, including dermis, subcutaneous fat, fascia, and muscle, as well as other structures. (See 'Introduction' above and 'Morbidity and mortality' above.)
●Surgical exploration – Whenever a diagnosis of NSTI is suspected, surgical exploration is indicated to confirm the diagnosis, if it remains in question (particularly in high-risk patients such as those with diabetes, or immunocompromised patients), and to perform debridement to the extent that is deemed necessary based upon the appearance of the tissues and the patient's general clinical condition. We suggest that the initial debridement be performed at the facility where the diagnosis is first suspected, rather than delaying debridement to transfer the patient, provided an appropriately experienced surgeon is immediately available at the presenting facility to perform the procedure. Delays in surgical treatment are associated with worse outcomes and higher mortality rates. Once the initial debridement has been performed, we further suggest referral to a tertiary/quaternary care institution with a multidisciplinary environment accustomed to managing complex wounds of this nature and extent for subsequent debridement, soft tissue reconstruction, and rehabilitation (such as a burn center). (See 'Surgical exploration' above.)
●Antibiotics – Empiric antimicrobial therapy should be initiated, if not already started, re-dosed intraoperatively, as determined by the length of the procedure, and continued postoperatively until the responsible organism(s) are determined from debridement specimens. Ongoing empiric therapy should cover both gram-negative and gram-positive organisms, including methicillin-resistant Staphylococcus aureus (table 4), combined with an anti-ribosomal agent (eg, clindamycin) to cover gram-positive organisms potentiating rapidly progressive NSTI via exotoxin production. Definitive treatment should be tailored to Gram stain, culture, and sensitivity results, when they become available. (See 'Antibiotics' above.)
●Adjunctive procedures – The intraoperative findings are often more severe than the preoperative evaluation, and the possibility that additional (eg, ostomy) or more extensive procedures (eg, extremity amputation) may need to be performed should be discussed with the patient and their family or other caregivers. A realistic impression of the prognosis should be conveyed. (See 'Informed consent' above and 'Adjunctive procedures' above.)
●Surgical debridement – The initial surgical debridement should be undertaken aggressively. The debridement should extend into healthy tissue until normal bleeding is observed and the surgeon is certain there are no areas of extension. Multiple tissue biopsies and cultures should be obtained from several sites and sent for microbiological and histologic evaluation to confirm the responsible organism(s) and to guide antimicrobial therapy. During the course of initial and subsequent debridement, the wound should be repeatedly and copiously irrigated with a broad-spectrum antiseptic solution. Once the debridement is completed, an antiseptic dressing should be applied. Negative pressure wound therapy, with or without instillation, has proved an obligatory adjunct once source control has been obtained, to prepare the wound bed, instill antiseptics, or facilitate optimal graft adhesion. (See 'Surgery' above and "Negative pressure wound therapy".)
●Second-look surgery – Second-look surgery is obligatory and should be undertaken within 24 hours after the initial debridement. On average, three to four debridements will be needed. In addition to standard postoperative bloodwork and regular clinical evaluation, we suggest obtaining procalcitonin, C-reactive protein, and lactate levels every six to eight hours. These laboratory markers of infection may assist in the timing of repeat debridement. Negative pressure wound therapy, with or without instillation, has proved an obligatory adjunct once source control has been obtained, to prepare the wound bed, instill antiseptics, or facilitate optimal graft adhesion. (See 'Second-look surgery and subsequent debridement' above.)
●Reconstructive surgery – No definitive coverage should be undertaken until all necrotic areas have been debrided. Once achieved, temporary coverage may be very valuable to protect the wound from desiccation and infection, reduce evaporative heat and fluid losses, limit the inflammatory and hypermetabolic response, thus enabling the patient to recover physiologically before it can be exchanged for definitive coverage. During this period, and once allograft is adherent, definitive wound coverage and closure should be planned and undertaken, which may include autografting, fasciocutaneous flap, or muscle flap coverage. (See 'Reconstructive surgery' above.)
آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
