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Appropriate coverage of defects that expose tendon, joints, and/or neurovascular structures is necessary to preserve optimal hand function. Local, random-pattern flaps and skin grafts may be inadequate because of the hand’s finite skin reservoir or the presence of a poorly vascularized and mobile wound bed. Described herein is a novel method of dorsal hand reconstruction.
A fasciocutaneous sliding flap and the underlying vascular anatomy of the dorsal hand are described. The flap takes advantage of the distinct fascial layers of the hand by raising the skin and fascia with bilevel undermining.
Conclusions and Relevance
The proposed single-stage, bilevel undermined fasciocutaneous sliding flap based on the perforating vessels running through fascial septae recruits pliable, easily mobilized skin, preserves neurosensory innervation, and facilitates early hand mobilization with reduced postoperative care. This flap, and its proposed variations, are ideal for use when paratenon is exposed and immobilizing the hand would be necessary for graft survival or when tension at the wound precludes reconstruction with primary closure or a traditional flap.
Because of the hand’s finite reservoir of skin and thin dermis and subcutaneous fat, random-pattern flaps have increased risk for necrosis or dehiscence from excessive tension. If tension precludes a random-patterned local flap, then a skin graft with prolonged immobilization of the hand may be necessary. For moderately sized defects of the dorsal hand not amenable to random-pattern flaps or grafting, we propose a sliding fasciocutaneous flap, whose blood supply derives from dorsal perforating arteries and which uses bilevel undermining at the dorsal superficial lamina and dorsal deep lamina for improved flap mobility. This novel reconstruction preserves both form and function and allows for quick recovery and return to daily activities.
Report of a Case
After resection of a squamous cell carcinoma on the dorsal hand of a woman in her 70s, a 3 × 2-cm defect extending to the dorsal intermediate fascia was repaired with a novel fasciocutaneous sliding flap based on the perforating arteries of the dorsal arterial system of the hand. The patient provided consent for this publication.
This flap may be used to repair superficial defects, as well as defects that extend down to tendon and bone that are situated on the dorsal surface of the hand between the metacarpophalangeal joints and the extensor crease of the wrist. Flap design should account for the size and site of the defect, as well as the mobility of the donor skin. The defect should be measured by instructing the patient to “make a closed fist.” This provides a conservative estimate of the size of the flap necessary to tolerate the anticipated postoperative tension generated with hand motion. The lateral borders of the flap may then be designed proximally off of the defect as 2 lateral limbs that arise from the widest portions of the defect. A third limb should connect the 2 lateral flap limbs. The length of the lateral limbs should be at least 1.5 to 2.0 times the defect diameter to incorporate a sufficient number of dorsal perforating arteries. These lateral flap limbs may parallel one another to create a rectangular flap, or they may gently diverge from one another so that an arciform or keystone shape is created. For defects that will be under tension, the keystone design allows for easier recruitment of skin with the V-Y closure at the proximal corners (Figure 1A). Because the abundance of the dorsal hand blood supply is derived from the dorsal metacarpal arteries and their perforators that run between the carpal bones, flaps designed centered over and incorporating multiple intercarpal spaces are more likely to have greater vascularity. Doppler ultrasound was not used in our clinical practice but may be helpful to locate perforators preoperatively.
A, Note that the parallel limbs of the flap are longer than the diameter of the defect. The increased flap length increases the likelihood of including an adequate number of perforator vessels. B, The flap incised through skin and fat only on the ulnar and proximal sides, with dorsal superficial fascia intact; the radial side has been incised through the dorsal superficial and dorsal intermediate fascia to the level of the paratenon. C, Undermining in the dorsal deep lamina. The extensor pollicis brevis tendon is visible and the cotton-tipped applicator achieved blunt dissection. D, The fascial pedicle on the ulnar and proximal limbs has been preserved with undermining in the more superficial subcutaneous fat plane. E, The flap has undermined sufficiently. The extensor pollicis brevis and extensor pollicis longus tendons are visible. Perforators from the ulnar branch of the first dorsal intermetacarpal artery have been preserved in the space between the first and second carpal bones. F, The flap’s leading edge rotates easily to reach the distal end of the defect. G, Flap sutured into place. H, Six weeks after surgery.
Once the flap is designed, all 3 flap limbs are gently incised through the dermis and superficial subcutaneous fat to the level of the dorsal superficial fascia (Figure 1B). This layer is readily identified by its glistening white color and the veins that it invests. To access the deeper undermining plane and gain additional mobility, 1, 2, or 3 limbs of the flap are further incised through the dorsal superficial and intermediate fascia to the level of the dorsal deep lamina immediately superficial to the paratenon and dorsal deep fascia (Figure 2). Frequently, only 1 lateral limb is incised to the deeper plane initially, undermining is performed, and flap mobility is assessed prior to incising through additional flap limbs. As more limbs of the flap are released, more mobility may be gained, but flap vascularity grows more tenuous, especially if the flap is not centered over a generous supply of perforating arteries.
Note the distinct layers of the dorsal hand and the important structures contained within the laminae.
Undermining that occurs in the plane above the paratenon and dorsal deep fascia should be done bluntly to preserve perforator arteries when possible (Figure 1C). The perforating arteries have a small diameter of 0.1 to 0.3 mm, so they are not readily visible. However, their presence can often be intuited by a focal restriction on the ability to reflect the flap back or by a focal point of restriction on advancement of the flap. When perforator arteries are severed, the surgeon will note both bleeding and a sudden increase in flap mobility as a vertically oriented vascular “tether” is released.
For flaps on the dorsal hand, the midpoint between the carpal bones should be preserved whenever possible because the underlying dorsal metacarpal artery and its perforators emerge along this line. For flaps based on the second through fourth web spaces, the area immediately distal to the juncturae tendinum, which is approximately 1 cm proximal to the metacarpal heads, should be preserved to protect the Quaba’s perforators. The fascial pedicles of the bipedicled and sling variations of this flap may provide sufficient random blood supply, even if the perforators under the flap have been severed.
Once the flap has been adequately released to the paratenon on the desired limb(s), the remaining attached limbs are undermined in a more superficial plane immediately in the subcutaneous fat to mobilize the fascial pedicle (Figure 1D). Once the flap has been sufficiently released and undermined, it should easily move into the defect without undue tension (Figure 1E and 1F). A layered repair should be able to secure the flap in a tension-free manner with preserved function and range of motion just after closure (Figure 1G and 1H).
Successful reconstruction of hand defects must allow patients to avoid postoperative hand dysfunction and quickly return to daily activities and work. Second intention healing may desiccate vital tissue such as tendon, and layered side-to-side repairs may compromise hand function because of closure tension. In the absence of a well-vascularized bed in defects that expose bony prominences and tendon, skin grafts are unreliable and fail to provide a gliding surface for the underlying mobile structures.1 Adhesions and fibrosis may ensue, potentially compromising tendon motion.2 Commonly used local cutaneous flaps for reconstruction of larger defects on the dorsal hand may be limited by a finite reservoir of adjacent donor skin and can lead to substantial donor site morbidity, prolonged rehabilitation, or ischemia.1,3
A novel approach to repairing dorsal hand soft-tissue defects is proposed whereby the distinct anatomic layers of the dorsal hand anatomy are mobilized to create a vascularized sliding flap. The strategy for mobilization of this flap and other variations was extrapolated from the anatomic investigation of cadaver hands of Bidic et al.4 They elegantly described the distinct fascial layers and accompanying structures via anatomic dissection, Doppler ultrasound, and lead oxide injections. Whereas Bidic et al4 sought to improve cosmetic hand rejuvenation, we believe that their findings are particularly salient for reconstruction after skin cancer resection. The reliable and reproducible fasciocutaneous sliding flaps may be implemented to cover defects with exposed tendon and reduce the likelihood of ischemia that may be seen with grafts and random-pattern cutaneous flaps. In addition to preservation of hand neurosensory function, use of adjacent tissue allows sensory discrimination to remain intact through the avoidance of skin grafting. This novel flap is ideally suited for moderately sized defects with a wound bed that is mobile with hand movement, increasing the risk of graft failure, or where tension is high and full flexion would have a high risk for dehiscence of a linear closure.
Axial, paddled flaps of the dorsal hand and wrist that are based on perforators of the dorsal metacarpal artery are often used to cover defects on the dorsum of the hand and fingers. These flaps and their corresponding blood supply have been reviewed comprehensively elsewhere.5,6 The sliding fasciocutaneous flaps described herein are not truly axial, but their blood supply is robust. Consistent cutaneous perforator vessels from the parallel arrangement of the dorsal arterial network permit these sliding flaps to be raised and mobilized with a reduced risk of ischemia when compared with random-pattern flaps based on the dermal plexus. Often, there is a communication between the palmar and dorsal systems, which may further reinforce blood flow to these flaps.6-8
The fasciocutaneous sliding flaps derive their primary blood supply from a series of perforating arteries from the dorsal and palmar arterial systems of the hand (Figure 3). The skin of the proximal two-thirds of the hand is supplied by the dorsal metacarpal arteries, which run parallel to the metacarpal bones within the fascia of the dorsal interosseous muscles deep to the extensor tendons.5,9 Each of the dorsal metacarpal arteries supplies blood to the dorsal skin of the hand via 4 to 8 cutaneous perforator vessels (diameter, 0.1-0.3 mm) that arise along its length.9 The number and diameter of perforators are larger at the level of the distal third of the metacarpal compared with the proximal and central thirds.9
The skin of the distal third of the hand and proximal digits is supplied by perforating arteries from the palmar arterial system. The common digital arteries, which arise from the superficial palmar arch, branch at the web space to connect with the dorsal metacarpal arterial system. The palmar metacarpal arteries, which arise from the deep palmar arch, also anastomose with the dorsal metacarpal artery at the web space and give off perforators to the dorsal skin.5 Skin perforators, called the Quaba perforators, consistently arise 1 cm proximal to the metacarpal head immediately distal to the juncturae tendinum, then ramify in retrograde fashion to supply blood to the skin of the distal dorsal hand.
Our proposed flap design has several distinct advantages compared with other methods of dorsal hand reconstruction. First, the bilevel undermining creates a highly vascularized flap based on both vertical perforating arteries and a vascularized sling pedicle. This robust vascular supply facilitates rapid, reliable wound healing and reduced postoperative care restrictions, which allows early hand mobilization with prompt return to unrestricted hand function. Second, the broad flap design benefits from mobilizing distant tissue reservoirs situated circumferentially around the wound; this permits diffuse distribution of the tension vectors necessary for wound closure and allows for recruitment of skin from several distinct tissue reservoirs that are less likely to “compete” with one another. This flap design broadly distributes the secondary motion required for flap closure, so limitations on joint mobility are less pronounced. Third, this single-stage reconstruction produces minimal donor site morbidity and delivers nearby pliable skin with good color and texture match to the recipient area. Using adjacent tissue with an intact neurovascular supply and avoiding skin grafts or dermal substitutes allows the defect to be repaired with sensate tissue, thereby preserving sensory discrimination.
Over the past 18 months, 2 of us (J.F.S., C.J.M.) have performed a variation of this flap on 15 dorsal hand defects. We categorize the 4 versions of the dorsal fasciocutaneous sliding flap as follows: (1) bipedicled bridge, (2) 2-sided sling, (3) 1-sided sling, and (4) keystone. All 4 variations similarly take advantage of the distinct fascial layers of the hand by raising the skin and fascia with bilevel undermining (Table and eFigures 1-3 in the Supplement). The complication rate for this flap is low. Patients often experience transient, self-resolving distal hand edema. Distal edge ischemia occurred in 2 patients. We believe that this can be minimized by observing the following precautions: (1) designing the flap 1.5 to 2.0 times the defect diameter when the hand is closed as a fist; (2) centering the flap over the intercarpal spaces, where perforating arteries abound; and (3) limiting the number of flap limbs that are deepened to the dorsal deep lamina.
A variety of local and regional flaps exist for soft-tissue defects of the dorsal hand, many of which can lead to substantial donor site morbidity and prolonged healing. Ideal reconstruction of soft-tissue hand defects should allow patients to avoid postoperative hand dysfunction, quickly return to daily activities, and preserve sensory discrimination. The proposed novel bilevel undermined fasciocutaneous sliding flaps based on the dorsal intermediate lamina and its investing fascial layers create highly vascular and mobile tissue for reliable coverage of soft-tissue defects on the dorsal hand. These flaps are ideal for use when paratenon is exposed and immobilizing the hand would be necessary for graft survival or when tension at the wound precludes reconstruction with primary closure or a traditional flap.
Corresponding Author: Joseph F. Sobanko, MD, Hospital of the University of Pennsylvania, Dermatology, Perelman Center for Advanced Medicine, 3400 Civic Center Blvd, 1-330S, Philadelphia, PA 19104 (firstname.lastname@example.org).
Accepted for Publication: April 18, 2014.
Published Online: July 30, 2014. doi:10.1001/jamadermatol.2014.954.
Author Contributions: Drs Sobanko and Miller had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: All authors.
Acquisition, analysis, or interpretation of data: Sobanko, Etzkorn, Miller.
Drafting of the manuscript: All authors.
Critical revision of the manuscript for important intellectual content: All authors.
Administrative, technical, or material support: Sobanko, Fischer, Etzkorn.
Study supervision: Sobanko.
Conflict of Interest Disclosures: None reported.
eFigure 1. Bipedicled Bridge Flap Design
eFigure 2. Keystone Flap Design
eFigure 3. One-Sided Sling Flap Design
Sobanko JF, Fischer J, Etzkorn JR, Miller CJ. Local Fasciocutaneous Sliding Flaps for Soft-Tissue Defects of the Dorsum of the Hand. JAMA Dermatol. 2014;150(11):1187–1191. doi:10.1001/jamadermatol.2014.954
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