Plantar Skin Flaps On Diabetic Ulcers: Are They Worth It?
Yes, the authors say skin flaps can be a viable option if conservative wound care fails. They emphasize that flaps can provide a unique match to the soft tissue properties of weightbearing areas and facilitate healing in wounds with exposed bone and tendon. By Gary P. Jolly, DPM, and Thomas Zgonis, DPM Historically, the treatment of chronic foot wounds has centered around aggressive debridement, pressure reduction and, lately, the application of wound healing accelerators such as various growth factors. More recently, the use of reconstructive procedures has been gaining support among reconstructive foot and ankle surgeons as an alternative to traditional offloading endeavors in this subset of patients since these reconstructive procedures seem to hasten the process of wound closure. Does the use of both random and pedicle skin flaps offer any advantages over conservative wound management? The answer is somewhat ambiguous. When it comes to wounds in nonweightbearing areas such as the arch or the side of the foot, one may allow these to close by secondary intention without complication. Similarly, partial thickness wounds on the plantar surface of the foot may also be allowed to close by secondary intention. However, when dealing with a wound on a weightbearing area that penetrates to the fascia or beyond, it is much less likely to close by secondary intention and yield a stable and durable envelope because of the physical properties of the resulting scar. Taking A Closer Look At The Soft Tissue Properties Of The Sole Several flaps have been described as alternatives to healing by secondary intention. These flaps can be raised on the foot and leg, and used to repair defects on the weightbearing and nonweightbearing surfaces of the foot. The advantage of these flaps over healing by secondary intention is that their tissue properties closely resemble those of the lost tissue, and they will move harmonically with the surrounding soft tissue during weightbearing. The weightbearing areas of the foot are covered with a soft tissue envelope that is unique in its design and allows for the resolution of shear as well as axial loads. The glabrous skin of the sole is significantly thicker than the skin that covers the rest of the body. Given the sole’s thicker stratum corneum, penetrating injuries are largely avoided. Attaching the dermis of this area of skin to the fascial layer are a series of stout bands called the mooring ligaments. These mooring ligaments resist shear and prevent avulsion of the weightbearing skin during periods of activity. Located between these ligaments are fat bodies that are arranged in columns. These fat bodies provide a hydrostatic cushion and aid in shock absorption during foot strike. The skin, mooring ligaments and fat bodies form a functional unit with remarkably unique properties. Therefore, their loss requires replacement with tissue that has similar properties.1 Unfortunately, when wounds in this area close by secondary intention, the resultant scar is thick, inelastic and unable to move harmonically with the surrounding soft tissue. This dramatic difference in the elasticity and plasticity between the scar and the surrounding tissue results in the production of marginal strain during weightbearing and likely leads to microtears at the edge of the scar. Since the scar is immovable, it is subjected to increased friction during weightbearing, and the absence of sweat glands in scar tissue increases that area’s coefficient of friction. When full thickness defects of the weightbearing areas of the foot are closed primarily with either local or pedicle flaps, the replacement tissue is composed of skin, mooring ligaments and columnar fat bodies. As a result, the replacement tissue is able to move in concert with the surrounding tissue. An additional advantage to flaps is that they retain functional sweat glands, which help to lubricate the skin and reduce friction. Facilitating Less Monitoring And Less Ulcer Recurrence Plantar wounds that close secondarily require close supervision by both the patient and his or her podiatrist. Furthermore, recurrence of the ulceration after secondary healing is quite common. When one closes plantar wounds primarily with flaps, the resulting construct provides a supple and durable coverage without the need for constant monitoring. The recurrence rate is also extremely low, providing there are no underlying deformities acting upon the bottom of the foot.2-5 Exploring Other Clinical Scenarios In Which Flaps Could Be Beneficial Wounds with exposed bone are at high risk for developing osteomyelitis. Extended local wound care only increases this risk. Rapid closure of the wound would be the treatment of choice in these situations. One may provide wound coverage via local and distant flaps, or by using muscle flaps covered with a skin graft. Skin grafts also provide a simple method of wound coverage in non-weightbearing areas of the foot. They may be harvested as partial thickness grafts and applied to clean surgical wounds. One may utilize local (rotational, advancement and transpositional) flaps to cover wounds with exposed subcutaneous tissue, tendon, muscle or bone. Beginning in 1986 with the publication of Hidalgo and Shaw’s work on the neurovascular supply to the skin of the foot, numerous descriptions of these flaps and their outcomes have been published in the plastic, orthopedic and podiatric literature.6 These flaps are, by and large, simple techniques that provide excellent coverage for chronic wounds of the foot. Pedicle flaps, which contain a discreet and identifiable blood supply, may be raised from soft tissue adjacent or distant from the wound defect. Buncke and Colen described a technique for creating neurovascular skin islands that are based on the proper digital neurovascular bundles of the toes. These flaps may subsequently be used to provide coverage for plantar defects of the forefoot and even the heel.3,5,7,8 One may develop muscle flaps, the main alternative to cutaneous flaps, in order to provide well vascularized coverage over bone and to provide bulk over a large defect.9 The abductor hallucis, the abductor digiti minimi and the flexor digitorum brevis are often used to provide coverage for hindfoot ulcers.3,4 Emphasizing Appropriate Patient Selection And Other Key Considerations When it comes to ulcers in patients who have inadequate arterial perfusion, they are unlikely to heal, regardless of how they are treated. Unless one directs appropriate intervention toward improving the blood flow into the foot, healing is highly unlikely. One should avoid the protracted use of growth factors or biologicals in this subset of patients as this amounts to nothing more than casting seeds upon barren land. Patients with midfoot ulcers secondary to Charcot neuroarthropathy also do poorly with both conservative treatment and soft tissue reconstruction unless one addresses the underlying deformity. Reducing a convex deformity of the midfoot often produces a soft tissue redundancy that usually permits simple transverse elliptical excision of the wound and primary closure. Surgeons should only consider midfoot flaps if they are planning to perform a corrective midfoot osteotomy or ostectomy at the same time. While simple but aggressive plantar ostectomies for medial ulcers offer reasonably good outcomes, lateral midfoot ulcers are better addressed through arthrodesis/osteotomy of the midfoot.7,10 It should be acknowledged that surgery in an inadequately nourished patient is less likely to succeed than when it is performed in a patient who is well nourished. Similarly, a poorly controlled diabetic faces a greater risk of wound complication than a patient with well-controlled hemaglobin A1c.11 The successful management of the diabetic foot is only possible when there is a well-coordinated team, which includes a reconstructive foot and ankle surgeon, a vascular surgeon, an internist, a nutritionist and an infectious disease specialist. Primary Closure: A Cost-Effective Option For Chronic Wounds? Closure of plantar wounds by primary intention significantly reduces the duration of treatment and subsequently the cost.12-14 The costs associated with the treatment of chronic wounds are significant in terms of professional care and hospital charges as well as the outpatient costs of dressing materials and nursing visits. Besides the obvious financial impact, there are the psychological and social issues that arise when a member of the family is being treated for a chronic wound. In Conclusion One should not see soft tissue reconstruction for chronic diabetic foot wounds as a replacement for good traditional wound care, but rather as a viable alternative for wounds that are unresponsive to traditional care, or extensive wounds with exposure of bone and tendon. Most superficial ulcers can and should be treated conservatively, but it is quite comforting to know that viable alternatives are available if conservative treatment fails. Dr. Jolly (right) is the President of the American College of Foot and Ankle Surgeons. He is the Chief of Podiatric Surgery and the Director of the PGY IV Fellowship in Reconstructive Foot and Ankle Surgery at the New Britain General Hospital in New Britain, Ct. He is also a Clinical Professor of Surgery at the Des Moines University School of Podiatric Medicine and Surgery. Dr. Zgonis is an Associate of the American College of Foot and Ankle Surgeons. He is an Attending Surgeon at New Britain General Hospital in New Britain, Ct., and at the St. Francis Hospital in Hartford, Ct. He is in private practice at Connecticut Reconstructive Foot Surgeons, LLC in Hartford, Ct. References 1. Saraffian, SK. Anatomy of the foot and ankle. In Saraffian SK, editor. Functional anatomy of the foot and ankle. 2nd edition. Philadelphia: JB. Lippincott; 1993. p.346-8. 2. Moore JC, Jolly GP. Soft tissue considerations in partial foot amputations. Clin Podiatr Med Surg 2000;17:631-648. 3. Jolly GP, Zgonis T, Blume P. Soft tissue reconstruction of the diabetic foot. Clin Podiatr Med Surg 2003;20:757-81. 4. Zgonis T, Jolly GP, Blume P. A guide to closure techniques for open wounds. Podiatry Today 2003;16(7):41-48. 5. Dutch WM, Arnz M, Jolly GP. Digital artery flasp for closure of soft tissue defects of the forefoot. J Foot Ankle Surg 2003;42:208-14. 6. Hidalgo DA, Shaw WW. Anatomic basis of plantar flap design. Plast Reconstr Surg 1986;78:627-36. 7. Jolly GP, Zgonis T, Polyzois V. External fixation in the management of Charcot neuroarthropathy. Clin Podiatr Med Surg 2003;20:741-56. 8. Buncke HJ, Colen LB. An island flap from the first web space of the foot to cover plantar ulcers. Br J Plast Sur 1980;33:242-4. 9. Jolly GP, Zgonis T. Pedicle flaps for replacement of soft tissue defects of the foot. Chir del piede 2003;27:1-10. 10. Cohen BK, Zabel DD, Newton ED, Catanzariti AR. Soft-tissue reconstruction for recalcitrant diabetic foot wounds. J Foot Ankle Surg 1999;38:388-93. 11. Stratton IM, Adler, AI, Neil HA, Matthews DR, Manley SE, Cull CA, Hadden D, Turner RC, Holman RR. Association of glycemia with macrovascular and microvascular complications of Type 2 diabetes: prospective observational study. Brit Med Journal 2000, 321:405-412. 12. Connoly JE, Wrobel JS, Anderson RF. Primary closure of infected diabetic foot wounds. A report of closed instillation in 30 cases. J Am Podiatr Med Assoc 2000;90:175-82. 13. Tennvall GR, Apelqvist J, Eneroth M. Costs of deep foot infections in patients with diabetes mellitus. Pharmacoeconomics 2000;18:225-38. 14. Apelqvist J, Ragnarson-Tennvall G, Persson U, Larsson J. Diabetic foot ulcers in a multidisciplinary setting. An economic analysis of primary healing and healing with amputation. J Intern Med 1994;235:463-71. No, the author believes these flaps are unnecessary in many cases, emphasizing that the keys to healing involve addressing the underlying cause(s) of the wound. By David G. Armstrong, DPM While I have undying respect for my profession — exemplified by my admiration for the lead author writing the “pro” side of this discourse — I am perpetually perplexed by the manner in which we place the therapeutic cart before the therapeutic horse. Nowhere is this better highlighted than in our love for covering defects in the skin through all manners of blade and bioengineering. While this is a laudable goal, the answer for healing a wound and keeping it healed lies underneath the skin. The equation for neuropathic diabetic foot ulceration can be summarized as pressure x activity = ulceration. Modulating both pressure and the number of times that pressure is applied to skin are critical to either healing a wound or to preventing it. My argument against the routine use of skin flaps as the primary means of addressing garden-variety plantar diabetic foot wounds is centered around two questions. • Why concentrate on covering the wound when there is a more important causative problem underneath (i.e. bony deformity, tendon imbalance) that should be corrected primarily? • After addressing the bony deformity, why spend an extra 15 to 45 minutes rotating a flap in place when the wound will most likely heal rapidly secondarily now that the primary problem (see above) has been ameliorated? I would argue that the skin coverage is secondary. Note that this argument does not take into account other frequent issues one encounters when performing skin plasties, such as creation of another wound that requires coverage (often from a skin graft), and the requirement for a higher degree of offloading than we can expect from most of our patients. What The Literature Reveals Where is the evidence to support this contention? Some of it lies in the very same manuscript that supports the use of skin flaps plantarly. In a well-written study, Blume et. al., relate a great deal of success with a “single stage” procedure in which they perform rotational or advancement flaps to cover plantar defects.1 What is not discussed as broadly is the fact that these patients also received correction of bony deformities. The discerning clinician might argue that these wounds would have healed just as readily and (for all intents and purposes) as quickly without rotating or advancing a thing. Where is the evidence to support this secondary contention? In a recent case control study published in Diabetes Care, we reported that patients receiving metatarsal phalangeal joint arthroplasties as treatment for plantar hallux wounds healed significantly faster than patients treated with aggressive offloading alone.2 Most patients in the surgery group healed their wounds within two to three weeks. I am sure that even the most ardent supporter of routine plantar plasties would agree that two to three weeks is about the time when sutures would be removed from a skin flap, assuming no dehiscence. Why is bone or skin work required at all? Well, in many cases, it is not (prior to healing). In our clinic, many patients with open plantar forefoot wounds receive either a) aggressive offloading alone or b) aggressive offloading plus a percutaneous Achilles tendon lengthening. In a study performed in 1999, our group suggested this procedure, performed in isolation, could reduce peak plantar forefoot pressure by a mean of 27 percent.3 Lin, et. al., found that patients receiving Achilles lengthenings coupled with total contact cast-based offloading healed significantly faster with a very low recurrence when compared with people who received total contact casting (TCC) alone.4 More recently, Mueller, Sinacore and co-workers, in an exquisitely crafted randomized controlled trial, found the magnitude of offloading identical to our aforementioned study. Going several steps further, their team found a reduced recurrence rate when performing this procedure.5 A Particular Case Study That Swayed My Thinking To offer full disclosure, I must admit that I went through a phase where I was quite enamored with rotational plantar flaps. All of that ended with one patient, who served as an interesting case control study. One might argue that experience with one patient should not an opinion make. I agree, but it can and does serve to crystallize nascent thoughts that are floating around in one’s head. This case involved a gentleman who had bilateral forefoot wounds that were identical in size and duration. As I recall, we performed simple isolated metatarsal head resections on both feet. My fellow was working with a resident on one side and I with a student on the other. My fellow, a very pleasant and erudite gent, elected to perform an advancement flap to close the wound on the left foot. As I was taking my time with my student, I elected to leave my side’s plantar wound open to fill in secondarily. I broke scrub after about 15 minutes to write my postoperative note. My fellow, even at that time a very skillful young surgeon, was still suturing as I left the room with the cuff at 35 minutes. Both sides healed beautifully within one week of each other. This is a testament to the primacy of removal or mitigation of the deforming force causing pressure. While this hasn’t stopped me from performing the occasional rotational flap (and the more frequent full-thickness graft), I now think twice about whether I’m doing it to speed healing or for “MRB” (Maximum Resident Benefit). Final Notes As I read the above words, I feel as though I am turning conservative in my old age. To allay that fear, let me say that I do believe there is a significant place for plantar (random and free) flaps in my teams’ practice. One can use these flaps to treat significant (i.e. large, very complex) wounds. However, those large, very complex wounds, even in our very busy tertiary care clinic, amount to approximately 10 percent of our patients at the most. If we allow ourselves to be distracted by this treatment for common plantar forefoot wounds, I would argue that we are wasting a) suture and b) (more importantly) our time and our patients’ time. Dr. Armstrong is the Director of Research and Education within the Department of Surgery, Podiatry Section, at the Southern Arizona Veterans Affairs Medical Center in Tuscon, Ariz. He is a Visiting Senior Lecturer of Medicine in the Department of Medicine at the Manchester Royal Infirmary at the University of Manchester in the United Kingdom. Dr. Armstrong is also a member of the Board of Directors for the American Diabetes Association. References 1. Blume PA, Paragas LK, Sumpio BE, Attinger CE. Single-stage surgical treatment of noninfected diabetic foot ulcers. Plast Reconstr Surg. 2002;109(2):601-609. 2. Armstrong DG, Lavery LA, Vazquez JR, et al. Clinical Efficacy of the First Metatarsophalangeal Joint Arthroplasty as a Curative Procedure for Hallux Interphalangeal Joint Wounds in Persons with Diabetes. Diabetes Care. 2003;26:3284-3287. 3. Armstrong DG, Stacpoole-Shea S, Nguyen HC, Harkless LB. Lengthening of the Achilles Tendon in Diabetic Patients Who Are at High Risk for Ulceration of the Foot. J Bone Joint Surg (Am). 1999;81A:535-538. 4. Lin SS, Lee TH, Wapner KL. Plantar forefoot ulceration with equinus deformity of the ankle in diabetic patients: the effect of tendo-achilles lengthening and total contact casting. Orthopaedics. 1996;19(5):465-475. 5. Mueller MJ, Sinacore DR, Hastings MK, Strube MJ, Johnson JE. Effect of achilles tendon lengthening on neuropathic plantar ulcers. A randomized clinical trial. J Bone Joint Surg. 2003;85A(8):1436-1445.