How To Prevent Plastic Surgery Failures In Lower Extremity Reconstruction

Author(s): 
Samir S. Rao, MD, and Christopher E. Attinger, MD

Whether it is diabetes, biofilms, biomechanical abnormalities or inadequate wound debridement, there are a number of factors that can lead to plastic surgery complications in lower extremity reconstruction. Accordingly, these authors emphasize a proactive
approach to managing patient comorbidities, reducing technical errors in surgery and
facilitating solid post-op protocols.

With advances in orthopedic, podiatric and plastic surgical technology and techniques over the past 30 years, we now have the ability to save limbs that previously would have been destined for amputation. However, our ability to save these limbs comes at the cost of more complex surgeries and more complications.

   Today’s patients are at higher risk for complications due to the rising incidence of morbid obesity and diabetes as well as the greater resistance of bacteria to antibiotics both in their planktonic form and within biofilm. Complication rates in lower extremity salvage and reconstruction surgery for acute wounds range from 18 to 50 percent depending on the timing of reconstruction.1

   Patient factors that contribute to complications include medical comorbidities (diabetes mellitus, renal failure, connective tissue disorders, coagulopathies, morbid obesity, malnutrition, etc.) and biomechanical abnormalities. The surgeon has little control over these factors, especially when facing an acute situation such as trauma or an infected wound. Our primary role in the management of these conditions is to facilitate subspecialist involvement to ensure these conditions are optimized prior to beginning the reconstructive process.

   Surgeon factors that contribute to complications include inadequate debridement, poor surgical decision making or planning, technical errors during surgery, and inadequate offloading or immobilization postoperatively. As surgeons, we have complete control over these factors and our goal should be to eliminate errors in these areas.

How Medical Comorbidities Can Spur Complications

Diabetes mellitus. The impact of diabetes on wound healing and lower extremity reconstruction is the subject of countless books, articles and even conferences. Regarding the lower extremity, it is the resultant neuropathy, vascular disease and advanced glycosylation of collagen in tendons and joints that are responsible for the great part of our challenges. The end-organ effects on the heart, kidneys and brain create systemic disease that make operating on the diabetic patient population even more challenging.

   In our practice, the management of diabetes is generally limited to tracking our patients’ blood sugars and hemoglobin A1C levels. When these levels are outside the normal range, we refer patients to a diabetes specialist if they are not already under the care of one. When our patients are hospitalized, we use a combination of their home diabetic medication regimens with sliding scale insulin and, when necessary, insulin drips. We have a low threshold for involving internists or endocrinologists in the management of diabetes in patients in whom we are unsuccessful controlling the disease ourselves.

   Renal failure. Renal disease causes many metabolic disturbances that have a negative impact on wound healing and increase the complication risk in reconstructive procedures. The uremia that results from renal failure decreases cell-mediated immunity and granulation tissue formation in open wounds. Renal disease also impacts the clotting process and can lead to problems with excessive bleeding and hematoma formation.2

   When operating on patients with renal failure, it is critical to ensure that a nephrologist is adequately managing their condition and that they are on a regular dialysis schedule. Any acute worsening of their renal status is grounds for delaying elective procedures until their condition has stabilized. Postoperatively, when it comes to patients with chronic renal insufficiency, we leave sutures in place for an additional two weeks in order to compensate for the delayed wound healing.

   Connective tissue disorders/steroid use. Patients with connective tissue disorders such as rheumatoid arthritis, lupus and scleroderma can be particularly challenging to treat due to the effects of both the disease processes and the treatment regimens on wound healing. Treatment regimens often require immunosuppressive drugs such as steroids and chemotherapeutic agents, which can have deleterious effects on tissues and wound healing.

   For patients with chronic steroid use, we recommend vitamin A supplementation with a regimen of 10,000 IU every other day or for the first 10 days of each month. Researchers have noted that vitamin A enhances steroid-retarded wound healing toward normal levels by restoring TGF-b and IGF-I levels, thereby reinvigorating the collagen production process essential for normal wound healing.3

   Coagulopathies. In patients with problematic wounds in whom other comorbidities are controlled and good blood flow is present, one should be suspicious of an undiagnosed coagulopathy. Upon further questioning, physicians may elicit a family history or even a personal history of blood clots. One can often identify abnormalities with Factor V Leiden, antithrombin III, protein C, protein S and homocysteine. In addition, 60 percent of patients with vasculitis can have an associated coagulopathy. We typically initiate a workup for these conditions with a standard coagulopathy laboratory panel. If we find any abnormal results, we employ the assistance of a hematologist or rheumatologist. We have found enoxaparin (Lovenox, Sanofi Aventis) therapy to be effective in these patients.

   Malnutrition. The role of nutrition in wound healing has long been recognized and multiple studies have since documented that malnutrition impairs the wound healing process.4 In addition to the cachectic patient, there may be concern for malnutrition in patients who have gastrointestinal disorders with malabsorptive components. It is also important to remember that obese patients can be malnourished.

   Clinicians commonly use serum protein markers to assess nutritional status. Pre-albumin is a typical marker to follow as it has a short half-life (three to five days) and represents the current nutritional status. Another benefit of pre-albumin’s short half-life is that one can utilize it to follow responses to interventions for malnutrition. This can be helpful for inpatients for whom surgery is being delayed until nutritional status improves. Albumin is another commonly utilized marker but its half-life is longer (two to three weeks). Accordingly, while it can provide a general idea of nutritional status, it is not as reliable in following recent trends.4

   We generally await pre-albumin values greater than 12 to 15 g/dL prior to any elective procedures. When it comes to patients with suspected malnutrition, there should be a low threshold for consulting a nutritionist.

Addressing Biomechanical Abnormalities

Biomechanical abnormalities due to decreased tendon or joint flexibility cause pressure points that are the cause of many problematic wounds especially when they are combined with neuropathy. The majority of these wounds occur in patients with diabetes, whose medical comorbidities further predispose them to difficulty with reconstruction efforts. Among the most common biomechanical abnormalities we encounter in our practice are Charcot arthropathy and a tight Achilles tendon.

   Our management of a wound caused by Charcot arthropathy consists of enlisting a foot and ankle surgeon to manage the skeletal problems. Unless a limb threatening infection is present, we prefer to address the arthropathy prior to any reconstructive procedures.

   A tight Achilles tendon, which limits ankle dorsiflexion and leads to prolonged gait cycle time on the plantar forefoot, is a common cause of plantar forefoot ulceration. We address this issue with a percutaneous tendon lengthening, a gastrocnemius recession or an Achilles tenectomy. Additionally, in patients with diabetes undergoing proximal forefoot and midfoot amputations, we perform a prophylactic Achilles tenectomy at the time of surgery. Preliminary data from our institution shows a reduced risk of future ulceration when patients undergo this procedure.5

Keys To Ensuring Adequate Blood Flow

Adequate blood flow is essential for wound healing. Adequate blood flow, as it pertains to wound healing and lower extremity reconstruction, can be defined as sufficient blood flow to permit wound healing at a rate of 15 percent or more per week.6 In the absence of infection or ischemia, patients with greater than 53 percent reduction in wound size over four weeks have a 58 percent chance of complete healing at 12 weeks.7 Given biphasic or triphasic flow, even single vessel extremities are candidates for lower extremity free flap reconstruction.8 Unfortunately, many patients requiring lower extremity reconstruction have concomitant peripheral vascular disease that will impede the wound healing process.

   Careful evaluation of blood flow should take place at the initial patient encounter as part of a standard history and physical exam. In addition to acquiring a detailed history of any vascular surgical procedures, physicians should look for any lower extremity surgical scars that may have compromised major vessels.

   They should also perform a detailed lower extremity Doppler examination. One can easily perform a thorough Doppler examination at the foot and ankle region in one to two minutes, and assess the patency of the anterior tibial artery, the posterior tibial artery and the anterior perforating branch of the peroneal artery. Additionally, determining antegrade versus retrograde flow by using selective occlusion can be important in planning local flaps and certain amputation procedures.9 Triphasic or biphasic signals are generally adequate for wound healing. Monophasic or absent signals in more than one vessel represent peripheral vascular disease, which a vascular surgeon should evaluate.

   Monophasic or absent signals from a vessel known to perfuse the angiosome containing a wound may represent a regional zone of ischemia. Addressing this ischemia is paramount to wound treatment. Neville and colleagues found that direct revascularization of the artery feeding an ischemic angiosome led to 91 percent healing and a 9 percent amputation rate.10 In comparison, indirect revascularization (bypass unrelated to the ischemic angiosome) led to only 62 percent healing with a 38 percent amputation rate. This data supports the principle that direct revascularization of the angiosome specific to the anatomy of the wound leads to a higher rate of healing and limb salvage.

Underscoring The Importance Of Adequate Debridement And Biofilm Removal

Inadequate debridement with incomplete elimination of infection and biofilm is unlikely to produce the clean, healthy wound bed necessary for healing and ultimate closure. A common error is to be conservative with debridement because of concerns about having sufficient tissue for wound closure. This is a setup for future breakdown secondary to infection.

   Surgeons should perform debridement independent of a reconstructive plan because the true defect will not be known until a wound has undergone adequate debridement and may be much larger than initially envisioned. An easy guide to adequate debridement is to debride until the wound base consists of normal colors: red (muscle), yellow (fat, bone) and white (tendon, fascia).

   The goals of debridement are to remove all foreign material, bacteria and inhibitors of wound healing (e.g. metalloproteases), leaving a clean, well vascularized wound bed. In recent years, biofilm has been recognized as a critical and potent barrier to achieving a clean wound.

   Biofilms are communities of microorganisms that reside in chronic wounds, are attached to a surface and embedded within a matrix of extracellular polymeric substances.11 They create a real challenge in wound healing because they form quickly (24 to 48 hours), are resistant to antibiotics (50 to 1500-fold) and biocides (hydrogen peroxide, acids, bleach), and they evade the host immune system (white blood cells, antibodies, complement). Physical removal and suppression of biofilm reformation are therefore necessary parts of the wound management regimen. The literature has demonstrated that debridement is the most effective modality to achieve this.12 Biofilm can penetrate as much as 4 mm from the wound bed surface by traveling down microvasculature and are accordingly difficult to remove.13

   Debridement is the cornerstone of our lower extremity reconstructive practice. We are aggressive with wound debridement and conservative with regard to closure. Single stage debridement and wound closure is the exception rather than the rule. It is common for our patients to undergo two to three surgical debridements in the operating room prior to closure. A commonly listed number in the literature is that the quantitative bacterial load should be 5 organisms/gram of tissue to allow wound healing.

   However, at our institution, we cannot easily obtain quantitative cultures. Rather, we rely on qualitative cultures that allow our antibiotic regimens to be culture driven. We typically use negative pressure wound therapy (NPWT) dressings in between operative debridements. In general, we will not close a wound until our post-debridement cultures indicate that the wound is clean. An inability to achieve a clean wound after multiple debridements or cultures that grow multi-drug resistant bacteria for which there is not adequate antimicrobial coverage are indications for an amputation.

Emphasizing Sound Surgical Planning And Decision Making

Poor surgical decision making and planning alone can be responsible for complications and failure. For instance, surgeons should plan incisions to avoid compromise of vessels perfusing surgical areas of concern. One should also plan incisions with known complications in mind as a misplaced incision may preclude certain salvage procedures in the future. Authors have previously described safe incisions in the foot and ankle region.9

   Other common errors include: closing a wound under too much tension; not covering debrided osteomyelitis with well vascularized tissue; not removing hardware in the region of an infected wound due to concern of instability; or not placing drains.

   Consider decisions that may not affect the outcome but may affect patient comfort postoperatively. For instance, when a patient is prone, it is often easy to take a skin graft from the posterior thigh. However, postoperatively, patients will have pain anytime they sit in a chair or on the toilet until the donor site heals. One can just as easily take a skin graft from the lateral thigh to avoid this problem.

   Technical errors in lower extremity reconstruction are often the result of not following the basics of repair. For example, we must always be careful to handle tissues in gentle manner. When closing skin, it is important not to squeeze the skin edges with forceps as this damages the tissue. When tying knots, consider the effects of postoperative swelling and ensure that excessive tension is not present. When dissecting flaps, know the anatomy and be aware of the correct tissue planes. Avoid leaving ridges of tissue that subsequently have the potential to become ischemic, creating a nidus for infection.

What You Should Know About Skin Grafts And Free Flaps

Skin grafts are one of the most common means that surgeons employ to close lower extremity wounds. While the technique is simple, skin grafting is still fraught with complications and failure. In one recent study of skin grafting in 73 diabetic foot wounds with bone and tendon exposure, there was a 26 percent non-healing rate at one month.14 In another recent study of 83 diabetic foot and ankle wounds, only 65 percent of patients healed uneventfully with 28 percent requiring re-grafting.15 The most common causes of skin graft failure, given an adequately vascularized wound bed, are infection, hematoma or seroma, and shear forces. We have already discussed the importance of adequate debridement in wound bed preparation.

   One method of addressing the other causes of skin graft failure is to use negative pressure wound therapy (NPWT) as a postoperative skin graft dressing. In a recent study by Blume and co-workers comparing the use of NPWT versus conventional therapy, the NPWT group required fewer repeat skin grafts (3.5 percent versus 16 percent), had higher graft acceptance rates (97 percent versus 84 percent) and had fewer complications with regard to hematoma, seroma and infection.16

   Most series of lower extremity free flap reconstructions report failure rates below 10 percent.16 However, due to vascular injuries and peripheral vascular disease, some series have failure rates as high as 20 to 30 percent.8 The leading causes of free flap failure are technical errors such as poor flap harvesting, improper microvascular technique or improper insetting.17 Poor harvesting and improper insetting lead to complications in local flap reconstruction as well.

Essential Postoperative Pearls

Without adequate postoperative offloading and immobilization, the most perfectly planned surgery performed with immaculate technique in the medically optimized patient may still break down and fail. For most patients undergoing lower extremity reconstructive procedures, basic offloading devices will be sufficient if patients are still adherent with their weightbearing status. Examples of these basic devices include posterior splints, post-op shoes, Ortho Wedge shoes (Darco), multipodus boots and controlled ankle motion (CAM) walkers, often in conjunction with the use of crutches, rolling walkers or wheelchairs.

   In non-adherent patients or in cases of lower extremity local or free flaps that must be protected, more extreme measures are often needed. In our practice, this often involves the placement of an external fixator. While this may seem drastic at times, in our experience, it is the only way to effectively offload or immobilize a subset of patients. Employing Ilizarov hardware and techniques may address any concomitant biomechanical abnormalities.

In Summary

We have the privilege of working in an era of reconstructive medicine that enables us to save limbs that previously would have been destined for amputation. Salvage of these limbs presents a unique set of complications and challenges, but following certain principles can lead to more predictable outcomes. We have discussed several factors that are common causes for complications or failures in lower extremity reconstruction.

   We have little control over the patient-related factors so our goal in their management is to assist in their optimization. We have complete control over the surgeon-related factors so our goal is to eliminate mistakes in these areas. When this happens, we can perform lower extremity reconstruction in a successful and professionally rewarding manner.

   Dr. Rao is a resident in the Department of Plastic Surgery at the Georgetown University School of Medicine in Washington, D.C.

   Dr. Attinger is a Professor in the Department of Plastic Surgery at the Georgetown University School of Medicine in Washington, D.C.

References

1. Kasabian KK, Karp NS. Lower extremity reconstruction. In: Thorne CH, Beasley RW, Aston SJ, Gartner CG, Spear SL (eds): Grabb & Smith's Plastic Surgery, 6th Ed. Lippincott Williams & Wilkins, Philadelphia, 2007.
2. Moran SL, Salgado CJ, Serletti JM. Free tissue transfer in patients with renal disease. Plast Reconstr Surg. 2004; 113(7):2006-2011.
3. Wicke C, Halliday B, Allen D, et al. Effects of steroids and retinoids on wound healing. Arch Surg. 2000; 135(11):1265-1270.
4. Arnold M, Barbul A. Nutrition and wound healing. Plast Reconstr Surg. 2006; 117(7Suppl):42S-58S.
5. Cunha M, Faul J, Steinberg JS, Attinger CE. Forefoot ulcer recurrence following partial first ray amputation: the role of tendo-Achilles lengthening. J Am Podiatr Med Assoc. 2010; 100(1):80-82.
6. Attinger CE, Janis JE, Steinberg J, et al. Clinical approach to wounds: debridement and wound bed preparation including the use of dressings and wound-healing adjuvants. Plast Reconstr Surg. 2006; 117(7Suppl):72S-109S.
7. Sheehan P, Jones P, Caselli A, et al. Percent change in wound area of diabetic foot ulcers over a 4-week period is a robust predictor of complete healing in a 12-week prospective trial. Diabetes Care. 2003; 26(6):1879-1882.
8. Ducic I, Rao SS, Attinger CE. Outcomes of microvascular reconstruction of single-vessel lower extremities: limb salvage versus amputation. J Reconstr Microsurg. 2009; 25(8):475-478.
9. Attinger CE, Evans KK, Bulan E, et al. Angiosomes of the foot and ankle and clinical implications for limb salvage: reconstruction, incisions, and revascularization. Plast Reconstr Surg. 2006; 117(7Suppl):261S-293S.
10. Neville RF, Attinger CE, Bulan EJ, et al. Revascularization of a specific angiosome for limb salvage: does the target artery matter? Ann Vasc Surg. 2009; 23(3):367-373.
11. Percival SL, Thomas JG, Williams DW. Biofilms and bacterial imbalances in chronic wounds: anti-Koch. Int Wound J. 2010; 7(3):169-175.
12. Wolcott RD, Kennedy JP, Dowd SE. Regular debridement is the main tool for maintaining a healthy wound bed in most chronic wounds. J Wound Care. 2009; 18(2):54-56.
13. Personal communication with J. Andy Schaber, MD, Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, Tx.
14. Yeh JT, Lin CH, Lin YT. Skin grafting as a salvage procedure in diabetic foot reconstruction to avoid major limb amputation. Chang Gung Med J. 2010; 33(4):389-396.
15. Ramanujam CL, Stapleton JJ, Kilpadi KL, et al. Split-thickness skin grafts for closure of diabetic foot and ankle wounds: a retrospective review of 83 patients. Foot Ankle Spec. 2010; 3(5):231-40.
16. Blume PA, Key JJ, Thakor P, et al. Retrospective evaluation of clinical outcomes in subjects with split-thickness skin graft: comparing V.A.C. therapy and conventional therapy in foot and ankle reconstructive surgeries. Int Wound J. 2010; 7(6):480-7.
17. Ong YS, Levin LS. Lower limb salvage in trauma. Plast Reconstr Surg. 2010; 125(2):582-588.

   Editor’s note: For related articles, see “Conquering Plastic Surgery Complications In Wound Care” in the July 2005 issue of Podiatry Today or “Pertinent Insights On Plastic Surgery And The Diabetic Foot” in the March 2011 issue.

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