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III. Extremity Soft Tissue Care and Amputation in an Austere Environment

MAJ Travis Burns, M.D.
A. Understand the factors that affect the care options for different patient groups (locals, detainees, foreigners/soldiers and those with evacuation options)
I. Introduction
            A. Patient categories in an austere setting
                        1. host-nation civilians
                        2. foreign noncombatants (third country nationals)
                        3. detainees/enemy combatants
                        4. U.S. military personnel
                        5. Allied forces personnel
            B. Providers may encounter injured personnel from all categories
            C. As situation matures, casualty care may become restricted
                        1. nationality or personnel category
                        2. injury type
            D. Medical rules of engagement established to create guidelines for patient care within personnel categories
            E. Priority of care for all patients must be according to medical urgency1
II. Determining a Treatment Plan
            A. Must take into consideration follow-on care after initial treatment; consider availability of evacuation, wound care supplies/capabilities, specialized surgical care, rehabilitation, medical supplies, prosthetics
            B. Patients with access to rapid evacuation and state of the art care and rehabilitation (U.S. personnel and those from supporting      nations)
                        1. must be stable for transport
                        2. immediate surgical care should focus on providing definitive care surgeons with the most reconstructive options
                        3. focus of initial orthopedic surgical care
                                    a. debriding devitalized soft tissue and contamination
                                    b. retaining viable soft tissue and bone for future reconstruction 
            C. Casualties who must remain in country for medical treatment and definitive care and rehabilitation
                        1. treatment plans tailored to in-country resources
                                    a. may need to be initially stabilized before transfer to local facilities for follow-on care
                                    b. may not have access to complex surgical reconstruction, wound care, rehabilitation, or prosthetics
                                    c. medical rules of engagement, evacuation assets, and future treatment capabilities will guide treatment decisions and may influence limb salvage decisions
                        2. non-salvageable lower extremity injuries (see figure 3, figure 4, and figure 5)
                                    a. attempt to maintain as much limb length as possible
                                                i. transtibial amputation – patients with access to prosthetics
                                                ii. Syme or Chopart amputation – patient without access to prosthetic fittings and devices
                                    b. to maintain soft tissue length in open amputation requiring transport greater than 72 hours or to obtain length in patient without other reconstruction options, consider skin traction
                                                i. stockinette wrap proximal to open wound can be used to anchor 6-8 pounds of skin traction to prevent soft tissue retraction
                                                ii. healing by delayed primary closure described by International Committee of the Red Cross (ICRC)6 
B. Define and demonstrate debridement
I. Introduction
            A. Debridement derived from French verb “débrider”
            B. Initially used to denote action of “cutting certain parts which—like a bridle—constrict or strangulate the organs which they cover”2,3
            C. Goal of surgical debridement
                        1. save lives
                        2. preserve function
                        3. remove contaminants and nonviable tissue to reduce risk of infection and associated complications
            D. Large zone of injury associated with high energy wounds
                        1. likely to evolve over time
                        2. likely to require serial surgical procedures4
            E. Viable tissue should be retained for reconstructive efforts at higher levels of care
II. Indications for Surgical Debridement
            A. Wound size greater than 2 cm
            B. Associated fracture
            C. Fascial defects
            D. Penetration of pleura, peritoneum, vascular structures, joint capsule
III. Wound evaluation and skin incision
            A. Wound debridement necessitates
                        1. extension of wound edges
                        2. exploration and inspection of the tissues within the zone of injury
                        3. removal of contamination and nonviable tissue
            B. Devitalized skin edges should be sharply excised
                        1. skin remarkably resilient
                        2. excision of large areas should be avoided except for grossly damaged or shredded skin
            C. For traumatic skin flaps, if base to length ratio exceeds more than 1:2, should be sharply excised
                        1. extension of traumatic wound usually made in long axis of limb
                        2. extensions across flexor creases should be done obliquely to prevent contractures
IV. Muscle and Subcutaneous Tissue Evaluation
            A. Damaged subcutaneous tissue and fascia are sharply excised
            B. Complete fasciotomies should be performed for compartments with elevated intracompartmental pressure
            C. Classic indicators to determine muscle viability (may be unreliable during initial evaluation)5
                        1. color
                                    a. least reliable sign for muscle viability
                                    b. surface tissue may be discolored due to contusion, blood under the myomesium, or local vasocontriction
                        2. consistency – ability to rebound to initial shape after grasping with forceps may be most reliable early sign
                        3. contractility
                                    a. assessed by observing retraction with pinch of forceps
                                    b. assessed by observing stimulus with electrocautery device
                        4. capacity to bleed – may be difficult to detect early due to vasospasm
            D. Sharp dissection utilized to remove devitalized tissue from wound incrementally
                        1. neurovascular structures in continuity left intact unless revascularization procedure necessary for arterial injury
                        2. neurovascular structures should be covered with muscle, fat, or skin, if  possible
                        3. tendons should be preserved and covered with local tissue
                        4. vacuum-assisted devices should not be used near exposed arteries, nerves, or veins
                        5. repeat assessment with serial surgical debridement likely to be beneficial in complex wounds (see figure 1 and figure 2)
            E. Challenging to appropriately balance wound debridement to minimize infectious complications with preservation of soft tissue for reconstruction; no objective measures or tests currently available to discern tissue to debride versus retain
            F. More aggressive debridement likely warranted if wound evaluation not possibly for greater than 24 hours
V. Osseous Evaluation 
            A. Necessary to deliver bone ends in open fractures for adequate debridement of fracture edges and intrameduallary canal
            B. Open wounds that penetrate joint capsule require arthrotomy and irrigation of intraarticular space
                        1. joint capsule should be reapproximated if tissue is available for closure
                        2. bone fragments lacking periosteum or soft tissue attachments are debrided
                        3. major articular fragments should be retained regardless of soft tissue attachments if joint is to be salvaged
VI. Irrigation
            A. After debridement, wounds irrigated with warm, low-pressure pulse irrigation or simple low pressure flow through sterile tubing
            B. Volume and type of irrigation not defined by scientific studies
                        1. volume depends on wound size and contamination
                        2. current recommendations
                                    a. grade 1 fractures – 3 L irrigation
                                    b. grade 2 fractures – 6 L irrigation
                                    c. grade 3 fractures – 9 L irrigation
            C. Antiseptics and antibiotics not recommended additives to irrigation solution
                        1. toxicity to host cells
                        2. lack of proven benefit
            D. Potable water can be utilized in austere environment if sterile solutions unavailable
VII. Postoperative Care
            A. Traumatic open wounds in austere environment should not be closed primarily to minimize risk of infectious complications
            B. Sterile dressings or negative pressure wound therapy devices should be used between procedures and during medical evacuation
            C. Splint should be applied to all severe extremity soft tissue wounds
                        1. patient comfort and soft tissue rest
                        2. should immobilize joint above and below zone of injury
            D. Open wounds reevaluated every 24-48 hours or after transfer to next level of care
            E. Need for repeat surgical debridement largely subjective
                        1. patient considerations
                                    a. evidence of persistent contamination
                                    b. devitalized tissue
                                    c. high energy mechanism
                                    d. local or systemic signs of infection
                        2. management issue considerations
                                    a. time until evacuation
                                    b. length of evacuation
                                    c. volume of other operative cases
VIII. Debridement Surgical Steps
            A. Administer appropriate IV antibiotics and tetanus prophylaxis for all penetrating wounds as early as possible
                        1. cefazolin 1 g q8 hours for gram-positive coverage
                        2. gentamicin 5 mg/kg/24 hours for gram-negative coverage
                        3. penicillin 2,000,000u IV q 4 hours for anaerobic/clostridia coverage
            B. Sterile preparation of the entire limb including prehospital applied tourniquet, as the extent of the zone of injury is not always evident
            C. Once surgical team prepared, and anesthesia has proper vascular access, field tourniquet released
            D. Control active hemorrhage
            E. Longitudinal extension of traumatic wound if necessary to evaluate soft tissue
            F. Excise nonviable tissue
                        1. necrotic skin and subcutaneous tissue
                        2. muscle that is friable, noncontractile, ischemic, severely damaged, or grossly contaminated
                        3. bone that is grossly contaminated or devoid of soft tissue
            G. Identify major nerves and leave in continuity – primary repair of transected nerves not performed in austere environment if definitive care resources available to patient
            H. Irrigate with low pressure pulsatile lavage or simple flow through cystoscopy tubing
            I. Flaps should not be fashioned for closure
            J. Leave wound open and apply sterile dressing
            K. Splint for soft tissue rest and comfort during transport
C. Describe the indications for and demonstrate the ability to perform austere environment amputations
I. Introduction
            A. Two distinct patient groups
                        1. early amputation performed for nonviable limb or a severely injured patient who is physiologically unable to tolerate limb salvage
                        2. definitive amputation performed on local nationals and other patients without access to higher levels of care
            B. Goals of initial care of severely injured patient
                        1. preserve life
                        2. prepare patient for evacuation, if available
                        3. leave maximum number of definitive treatment options
            C. Specific guidelines for indicating extremity amputation based on injury characteristics or physiologic parameters unavailable
            D. Possible indications for early amputation
                        1. extremity injury characteristics
                                    a. nonviable limb after debridement of devitalized tissue
                                    b. ischemic limb with greater than 6 hours of warm ischemia
                                    c. irreparable vascular injury or failed repair of ischemic limb
                        2. systemic characteristics
                                    a. severely injured extremity
                                    b. rising serum lactate levels
            E. If patient has viable limb and evacuation available, amputation indications more appropriately based on physiologic status than on predicted ultimate limb functionality
            F. Austere environment amputations should be performed at most distal level possible to retain options for future reconstructive efforts and minimize soft tissue retraction
                        1. all viable skin, soft tissue, and osseous length should be preserved during initial debridement
                                    a. viable soft tissue (muscle and skin) distal to the bone may be used as rotational flap and may enable patient to maintain more distal level amputation
                                    b. especially important for short tibial segments where distal soft tissue may be rotated to preserve knee function
                        2. fractures proximal to level of planned amputation need not decide amputation level and may be initially treated with external fixation or splint application
                        3. definitive treatment plan and level of amputation may be established after considering viable bone and soft tissue, availability of evacuation, expected prosthetic availability for patient
                        4. See figure 3, figure 4, and figure 5 for most commonly utilized levels of amputation
            G. See links below for video content and descriptions of surgical techniques for various upper and lower extremity amputation levels
            H. Skin traction
                        1. unnecessary in amputations that will be reevaluated within 24-48 hours
                        2. possibly warranted with longer delays prior to repeat evaluation
            I. Amputations should not be closed initially
            J. Sterile dressing or negative pressure dressing should be applied with splint for soft tissue rest during transport
II. Amputation Surgical Technique