6. Soft Tissue Coverage (Austere Environment) -- Flaps and Vacuum-Assisted Closure (VAC)

COL Richard Pope
MAJ Michelle Fontaine
CPT Charles Grooters
 
I. Soft Tissue Coverage in Austere Environment
            A. Normally best performed in controlled environment with availability of microscope or loupe magnification
            B. In rare circumstances, surgeons may need to perform soft tissue coverage procedures in austere environment when evacuation to higher echelon of care not feasible
            C. Ideal to obtain definitive coverage within ten days post injury, however
                        1. level of contamination in combat and disaster wounds requires multiple debridements
                        2. utilization of temporary coverage procedures such as negative pressure dressings prior to definitive coverage procedure
            D. Free-flaps
                        1. attempting to perform one in austere environment would have very high failure rate
                        2. adequate debridement of recipient wound bed cannot be stressed enough
            E. Flaps can provide
                        1. additional vascular supply to wound bed, increasing delivery of antibiotics
                        2. coverage of bone and implants
II. Forms of Soft Tissue Coverage
            A. Wound granulation – often assisted by wet-dry dressing changes or wound vacuum
            B. Flaps
                        1. axial – based on specific vessel
                        2. random – not based on specific vessel
 
 
A. Gastrocnemius Flap
 

Gastrocnemius Flap - Joe Hsu, MD

 
 
I. Introduction
            A. Either medial or lateral, muscle flap used for soft tissue coverage for knee, patella, and proximal one-third of tibia soft tissue defects
            B. Flap based on either lateral or medial sural arteries, which arise approximately 4 cm proximal to knee joint line
            C. After muscle flap raised and transposed, will require split-thickness skin graft (STSG) for dermal coverage
II. Pre-operative Assessment
            A. Thoroughly debride wound bed recipient of any necrotic tissue
            B. Posterior aspect of knee/calf should only have minimal trauma and intact vascular tree
            C. Use caution if there has been supracondylar femur fracture or knee dislocation
                        1. these injuries may have disrupted blood supply to heads of gastrocnemius, making it an unsuitable flap
                        2. may need to perform arteriogram in these cases to confirm vascular supply
            D. Elderly or very thin patients may have less than adequate donor muscle bellies
            E. Medial, lateral, or both gastrocnemius flaps can be used for coverage
                        1. lateral does not extend as far anteriorly when transposed
                        2. lateral will only provide minimal coverage past tibial tubercle
III. Surgical Technique
            A. Position patient supine with leg in external rotation to expose medial side of calf
            B. Start incision on medial aspect of leg
                        1. at about level of the knee joint
                        2. should extend down tibia to level of the start of Achilles tendon (see Figure 1)
            C. Take care to ensure adequate skin bridge of at least 7 cm between any existing incisions
            D. Open fascia of superficial posterior compartment
                        1. identify interval between soleus and gastrocnemius muscles
                        2. may be easily dissected with index finger
            E. Identified division between heads of gastrocnemius proximally and carry distally
            F. Elevated gastrocnemius distally with small portion of distal tendon and underlying fascia (see Figure 2)
            G. establish subcutaneous tunnel to recipient bed and transpose flap
                        1. take care to ensure flap is not compressed by skin bridge or fascia
                        2. if extra length needed, fascia can be pie crusted and medial head of gastrocnemius can be released from femoral condyle
                        3. take care to avoid vascular pedicle, which enters muscle approximately 3 cm above joint line
            H. Once transposed, use sutures through tendinous portion to inset muscle into wound bed
            I. Cover exposed muscle with STSG (see Figure 3)
            J. Close incision over a drain
 
Reference
 
Bos GD, Buehler MJ. Lower-extremity local flaps. J Am Assoc Orthop Surg. 1994;2(6):342.
           
 
B. Soleus Flap
 

Soleus Flap - Joe Hsu, MD

 
I. Introduction
            A. Reliable for soft tissue coverage of middle third of tibia
            B. Typically used for coverage over medial aspect of leg
            C. Can provide coverage laterally, but fibula limits mobility
            D. Main disadvantage is viability of distal portion of flap is tenuous secondary to minor pedicles, which must be sacrificed for mobilization
            E. Associated with little donor site deformity, but requires skin graft used to cover recipient site
II. Pre-operative Assessment
            A. Most important evaluation is assessment of soleus for damage that may have occurred during initial injury
            B. Soleus originates on proximal tibia and fibula, making it prone to injury during high energy tibia fractures
            C. During initial debridement, palpation may reveal penetration of soleus, which would preclude use for transposition
            D. Other signs of injury to soleus
                        1. significant posterior compartment swelling and ecchymosis
                        2. injury radiograph with significant displacement in sagittal plane
            E. Vascular studies not typically indicated
III. Surgical Technique
            A. Elevation of soleus is through longitudinal incision paralleling medial border of tibia from just below tibial plateau to just above medial malleolus (see Figure 4)
            B. Soleus most easily found in proximal leg, between gastrocnemius and deep transverse fascia
                        1. posterior tibial neurovascular bundle is protected
                        2. muscle is cleared on its deep and superficial surface (see Figure 5)
            C. Depending on area of graft needed, utilize either a complete soleus or hemisoleus flap            
            D. If using hemisoleus
                        1. must be divide soleus lateral to midline so that intermuscular artery is taken with flap
                        2. to free flap, divide it from Achilles tendon and ligate minor distal vascular pedicles as needed to allow rotation into defect (see Figure 6)
                        3. cover flap with STSG and close incision in standard fashion
            E. If using lateral approach to harvest soleus flap
                        1. realize that fibula will limit rotation
                        2. may gain further rotation by removal of fibula
III. Post-operative Care
            A. Elevate extremity and immobilize with posterior splint
            B. Avoid vaso-constrictive agents
                        1. caffeine
                        2. nicotine
                        3. cool temperatures
            C. Take care to ensure flap and overlying STSG are protected from shear stresses for first five days
 
References
 
Bos GD, Buehler MJ. Lower-extremity local flaps. J Am Assoc Orthop Surg. 1994;2(6):342.
 
 
C. Sural Artery Flap (Instructional Video - Windows Media Video | Mac, iPad Video)
 
I. Introduction
            A. Is fasciocutaneous axial rotation flap based on obtaining reverse flow from superficial sural artery, which accompanies sural nerve down back of calf
            B. Can be used to cover defects on distal one-third of leg and ankle/heel
            C. Can be used to cover defects up to 9 by 12 cm, however, there are concerns of necrosis with larger flaps
II. Pre-operative Evaluation
            A. Recipient wound bed needs to be completely debrided of all necrotic material
            B. Superficial sural artery should be examined from point where it penetrates fascia (approximately 20 cm above malleolus) to last perforator on lateral aspect (approximately 5 to 10 cm above lateral malleolus), which will be pivot point for flap
III. Surgical Technique
            A. After recipient wound bed completely debrided, measure it in order to template the size of flap
            B. Design flap to be slightly larger than required size to allow tension-free inset
            C. Identify sural artery and nerve proximally
                        1. usually penetrates the fascia
                        2. becomes superficial approximately 20 cm proximal to lateral malleolus
            D. Line from middle of popliteal fossa to point between peroneal tendons and Achilles tendon approximates the course of neurovascular bundle
            E. Design skin paddle to start 20 cm proximal to lateral malleolus, over muscular portion of gastrocnemius, ending approximately 10 cm proximal to lateral malleolus, including small extension over distal portion (see Figure 7)
            F. Raise flap from proximal to distal in subfascial layer, after ligation of superficial sural artery and lesser sapheneous vein (see Figure 8)
            G. Take cuff of adipose tissue, approximately 3 cm wide, from around vascular pedicle, extending to rotation point, but no further distal than 5 cm proximal to lateral malleolus
            H. Flap then rotated, without kinking vascular pedicle, and inserted into defect
            I. Distal extent of incision can be closed primarily and proximal portion may require STSG
 
References
 
Sauerbier M, Kremer T. The sural artery flap. In Master techniques in orthopaedic surgery: soft tissue surgery, 1st ed., Moran SL, Cooney WP, eds. Baltimore: Lippincott, Williams and Wilkins. 2009, p. 361.
 
Orr J, Kirk KL, Antunez V, et al. Reverse sural artery flap for reconstruction of blast injuries of the foot. Foot Ankle Int. 2010;31(1):59-64.
 
 
D. Radial Forearm Flap and Reverse Radial Forearm Flap
 

Pedicled Radial Forearm Flap Video - Michael A. Thompson, MD and L. Scott Levin, MD

 
 
I. Introduction
            A. Provides fasciocutaneous flap for coverage from elbow to hand
            B. Is very reliable flap based off perforating vessels between flexor carpi radialis (FCR) tendon and brachioradailis tendon
            C. Can provide up to 15 by 15 cm flap, which can be rotated from dorsum of hand (rotation point at wrist) to elbow (rotation point in proximal forearm), depending on rotation point of flap
II. Pre-operative Assessment
            A. Important to perform modified Allen's test using Doppler prior to performing flap in order to make sure that harvesting radial artery will adequately perfuse the hand, especially thumb and index finger
            B. Digital Doppler exam of pulp of each finger while compressing radial artery at wrist should be performed as part of assessment
III. Surgical Technique
            A. Ensure definitive debridement is completed and recipient bed is ready to accept flap
            B. Identify course of radial artery in forearm using Doppler
            C. Fashion template using hand towel or drape to ensure adequate length of pedicle for rotation to desired recipient site (see Figure 9A and Figure 9B)
            D. Make incision at distal extent of flap
            E. Identify and protect radial artery and accompanying veins
            F. Complete outlined skin incision down and through fascia without undermining plane between subcutaneous tissue and fascia
            G. Place tack sutures at edges of flap to ensure that cutaneous and fascial layers don’t separate (see Figure 10A)
            H. Subfascial dissection is performed from ulnar over flexor carpi ulnaris (FCU) toward FCR, then diving deep along intramuscular septa at radial border of FCR
            I. Peritenon needs to be left intact over all forearm tendons in order for skin graft to take after flap transposition
            J. Extreme care must be taken to preserve intramuscular septa, which contain perforators upon which flap is based
            K. After ulnar portion is complete
                        1. radial side of flap is elevated subfascial off brachioradialis
                        2. be careful to identify and protect intramuscular septa and radial artery
            L. During radial portion of dissection, superficial branch of radial nerve (SBRN) should be identified and protected
            M. If cephalic vein encountered, it also should be transferred with flap in order to improve venous outflow
            N. Then radial artery pedicle is developed in appropriate direction with enough length developed to perform tension free rotation of flap in recipient bed
            O. With proximal and distal control established, test viability of flap
                        1. place vascular clamp on appropriate end of artery and deflate tourniquet
                        2. once flap has been proven viable, divide artery at end of flap opposite rotation point (see Figure 10B)
            P. Flap can then be transferred to recipient bed
                        1. make incision for course of pedicle or by skin tunnel
                        2. ensure there is no compression on pedicle of flap and no kinking about rotation point
            Q. Flap can then be inset into recipient bed
            R. Cover donor site with STSG, with or without negative pressure dressing
IV. Post-operative Care
            A. Extremity must be elevated and immobilized with splint from elbow to finger tips that allows assessment of flap for vascular status every 4 to 8 hours
            B. Vaso-constrictive agents should be avoided
                        1. caffeine
                        2. nicotine
                        3. cool temperatures
            C. Be careful to ensure flap is protected from shear force stresses for first five days
 
Reference
 
Azari KK, Lee WPA. Radial forearm flap for elbow coverage. In Master techniques in orthopaedic surgery: soft tissue surgery, 1st ed., Moran SL, Cooney WP, eds. Baltimore: Lippincott, Williams and Wilkins. 2009, pp. 129-135.
 
 
E. Posterior Interosseous Artery (PIA) Flap
 
I. Introduction
            A. Is a fasciocutaneous flap that can be proximally or distally based
            B. Is based on posterior interosseous artery, which travels in intermuscular septum between extensor carpi ulnaris (ECU) and extensor digiti quinti (EDQ)
            C. Flap is harvested from dorsum of forearm
            D. Can provide coverage distally as far as proximal phalanges and as proximal as elbow
            E. Distally based flap (most common) used to cover defects on dorsal aspect of hand
                        1. Moderately sized flap (5 by 4 cm) able to reach dorsum of hand or first web space
                        2. In theory, entire dorsal forearm skin may be harvested, however, the larger the flap, the shorter the pedicle will be
            F. Proximally based flap (more rare) used to cover small defects (3 to 4 cm) over tip of olecranon or lateral condyle (in general, flap cannot be used if zone of injury encompasses dorsum of forearm)
II. Surgical Technique
            A. Ensure complete definitive debridement
            B. Position patient supine with elbow flexed at right angle
                        1. imaginary line from lateral epicondyle toward distal radioulnar joint (DRUJ) marks axis of flap (see Figure 11)
                        2. vascular pedicle emerges just distal to junction of middle and proximal third of this line
                        3. use handheld Doppler to confirm location of artery
            C. Flap is drawn out, with longitudinal incision extending distally toward DRUJ
                        1. incise radial aspect only of flap and distal longitudinal portion of incision (see Figure 12)
                        2. incise down through deep fascia, as that will be rotated with flap
                        3. use small sutures (4-0 or 5-0 Monocryl or nylon) to suture fascia to tissue of flap so it does not shear away during handling of flap
            D. Identify intermuscular septum by looking for septal arteries that pass through deep fascia out towards skin
                        1. in longitudinal distal portion of wound, fascia must be incised with parallel incisions on both sides of septum (see Figure 13)
                        2. retract ECU ulnarly
                        3. retract EDQ and extensor digitorum comminus (EDC) radially
                        4. need to incise septum between EDQ and EDC, but NOT septum between EDQ and ECU
            E. Dissection proceeds from distal to proximal
                        1. identify artery proximally as it emerges from supinator
                        2. PIA must then be freed from accompanying posterior interosseous nerve (PIN), located on radial side of PIA (see Figure 14)
                        3. PIA then ligated just proximal to first small arteriole to flap
            F. Next, raise ulnar border of flap
                        1. dissect vascular pedicle (kept within intermuscular septum) away from shaft of ulna (see Figure 15)
                        2. distally, vascular anastomotic arch must be released from interosseous membrane
                        3. if needed, ligating ramus perforans branch of anterior interosseous artery allows pivot point of pedicle to be more distal
            G. Now mobilize flap to dorsum of hand (see Figure 16)
                        1. either tunnel flap under intact skin or make incision over course of the pedicle
                        2. be careful not to kink or compress pedicle
                        3. inset flap with multiple interrupted nylon sutures
            H. Cover donor site by immediate STSG, unless small enough to be closed primarily
III. Post-operative Care
            A. Place extremity in short-arm cast (from elbow to fingertips) and elevate
            B. Perform vascular checks every 4 to 8 hours
            C. If possible, keep patient in warm room or place gentle warming blanket over arm
            D. Patient should avoid caffeine and nicotine
 
Reference
 
Zancolli EA. Posterior interosseous artery island flap for dorsal hand coverage. In Master techniques in orthopaedic surgery: soft tissue surgery, 1st ed., Moran SL, Cooney WP, eds. Baltimore: Lippincott, Williams and Wilkins. 2009, pp. 191-206.
 
 
F. Cross-finger Flap
 
I. Introduction
            A. Meant to provide soft tissue coverage to pulp of digits when they sustain oblique defect of pulp up to 2 cm in length
            B. Is a reconstructive option versus shortening finger and performing primary closure when tendon or bone exposed
            C. Tends to provide thicker, more resilient coverage than full-thickness skin graft
            D. Has advantage of being placed directly over exposed bone or tendon
            E. Contraindications
                        1. patient unavailable to return for flap division and inset 2 to 3 weeks after index procedure
                        2. adjacent (donor) fingers have sustained significant injury
                        3. vascular or Dupuytren’s disease
            F. Relative contraindications
                        1. patient over 50 years old (due to post-operative concerns of proximal interphalangeal joint contractures)
                        2. diabetes
                        3. rheumatoid disease
II. Surgical Technique
            A. Debride recipient finger wound back to viable tissue
            B. Make template of required coverage from handle towel or foil
            C. Choose most appropriate adjacent digit as donor site – consider ability to swing flap over defect with least amount of PIP flexion to recipient finger
            D. Elevate full thickness flap from dorsum of adjacent digit over P2, down to but not including the peritenon over extensor tendon (see Figure 17)
            E. Do not divide flap on side of injured finger, but place volarly over defect on recipient finger (see Figure 18)
            F. Secure flap with multiple interrupted sutures to recipient finger
            G. Cover donor defect with full thickness skin graft, normally taken from pinch graft in anitcubital fossa
III. Post-operative Care
            A. Apply splint to protect surgical site
            B. Bring patient back in 2 to 3 weeks for flap division and insetting
 
Reference
 
Elhassan BT, Shin AY. Cross-finger flaps for digital soft tissue reconstruction. In Master techniques in orthopaedic surgery: soft tissue surgery, 1st ed., Moran SL, Cooney WP, eds. Baltimore: Lippincott, Williams and Wilkins. 2009, p. 245.

The view(s) expressed herein are those of the author(s) and do not reflect the official policy or position of Brooke Army Medical Center, the U.S. Army Medical Department, the U.S. Army Office of the Surgeon General, the Department of the Army, Department of Defense or the U.S. Government.

Materials and support for The Disaster Preparedness Toolbox is provided by Lt Col. Ky Kobayashi, MD and Col. Benjamin Kam, MD.
 



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, April 15, 2014 10:54 am