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Practical Pearls On Plastic Surgery Techniques For The Diabetic Foot
Following primary procedures in the diabetic foot, reconstructive surgery may be required to ensure optimal wound closure. Accordingly, these authors discuss salient considerations for patient selection and wound preparation techniques, and offer pearls on a variety of flaps ranging from rotational flaps and local muscle flaps to pedicle flaps and perforator flaps.
Wound closure for the diabetic foot can be a challenging task and surgical reconstruction may provide a path to optimal outcomes. While local wound care might be effective for certain diabetic foot wounds, there are many complicated clinical scenarios when it is not successful and surgical intervention becomes necessary to facilitate wound closure.1
The podoplastic approach, defined as the combined use of plastic surgical wound closure techniques and circular external fixation, can help the surgeon achieve several goals.2 These include preservation of function and durable soft tissue coverage while simultaneously promoting anatomic alignment and stability. Circular external fixation can facilitate:
• surgical offloading through stabilization
• avoidance of extensive tissue dissection through the use of smooth wires and/or half-pins
• compression in arthrodesis procedures
• maintenance of anatomic alignment and/or correction of equinus deformities and
• elevation of the lower extremity to prevent pressure and allow access for flap observation and local wound care when necessary.
While multiple treatment choices are available for definitive closure of diabetic foot wounds, one must understand all the options as well as the optimal perioperative medical approach to provide exceptional care that is specific to each patient.
Setting The Stage For Successful Surgical Wound Closure
Key determining factors for a successful surgical wound closure in the diabetic population are appropriate patient selection, wound characteristics and medical optimization prior to surgery. The surgeon must be cognizant of many factors including a patient’s overall health status, the presence of multiple medical comorbidities, psychosocial issues and goals of care.
The initial evaluation involves clinical assessment of the patient and wound characteristics before determining an optimal treatment plan. Associated comorbidities such as peripheral arterial disease (PAD), venous stasis dermatitis, lymphedema, congestive heart failure, hypertension, anemia, renal disease, poor nutrition, uncontrolled blood glucose levels and peripheral neuropathy significantly increase the risk of postoperative complications. Unfortunately, the patient with diabetes mellitus who is in need of soft tissue reconstruction often has a multitude of comorbidities, including smoking, that may increase the risk for surgical complications. A comprehensive medical history and thorough physical examination will help elucidate the appropriate medical and surgical consultation services needed to optimize the patient with diabetes mellitus prior to surgery.
Since chronic hyperglycemia is known to affect wound healing, proper management of glucose levels by the patient’s primary care physician and/or endocrinologist throughout the perioperative period is highly recommended. A thorough preoperative vascular assessment including clinical presentation and non-invasive arterial studies may indicate the need for formal vascular surgery consultation to increase perfusion at the surgical site prior to reconstruction.
Another key to successful outcomes is eradication of any underlying soft tissue and/or osseous infection. One can address infection or bacterial colonization before the definitive soft tissue reconstruction through an initial surgical debridement and wound bed preparation, proper local wound care and offloading, antibiotic therapy and treatment of medical comorbidities. Infectious disease consultation is helpful in cases of multidrug resistance based on intraoperative cultures as well as cases of extensive osteomyelitis warranting long-term intravenous and/or oral antibiotic therapy.
Carefully evaluate appropriate medical imaging including initial plain radiographs. One should order more advanced imaging modalities such as magnetic resonance imaging (MRI), computed tomography (CT) and nuclear imaging based on the pathology and clinical scenario. Magnetic resonance imaging is helpful in identifying abscess formation and/or osteomyelitis. One can utilize CT in patients with chronic deformities caused by Charcot neuroarthropathy. Nuclear imaging can aid in differentiating between osteomyelitis and Charcot neuroarthropathy.
An Overview Of The Plastic Surgery Options
The options for plastic surgical reconstruction of the diabetic foot and ankle begin with primary wound closure after a surgical debridement and/or amputation. Each subsequent step leads to progressively more complex surgical techniques, such as autogenous split-thickness skin grafts (STSG) and orthobiologics, and ultimately ending with local flaps, muscle flaps, pedicle flaps, perforator flaps and free flaps.
Throughout this stepwise reconstructive surgical approach, multiple adjunctive therapies might be indicated to expedite and assist in proper wound bed preparation before the definitive plastic surgical reconstructive procedure. Such adjunctive therapies may include topical enzymatic debridement, negative pressure wound therapy (NPWT), hyperbaric oxygen therapy (HBOT), culture-guided antibiotics and offloading.3 In addition, staged surgical wound debridement to eliminate any remaining soft tissue and/or osseous infections may be necessary in many clinical scenarios before the definitive soft tissue closure.
Primary surgical wound closure in the diabetic foot may be feasible in cases of minor surgical debridement and/or amputations with localized soft tissue and/or osseous infection and without extensive ascending cellulitis, purulence, deep abscess or the presence of severe PAD. One can complement this type of wound closure with the use of local random flaps after surgical debridement of the non-viable tissues.
In contrast, severe diabetic foot infections and/or osteomyelitis necessitate extensive surgical debridement through staged reconstructive procedures before the definitive wound closure. Throughout the postoperative period, NPWT becomes a great tool that can assist in providing a healthy and granular wound bed ready for advancement to the next step of wound closure including autogenous STSG, allogeneic skin grafting or orthobiologics. In some clinical scenarios, NPWT may function as the definitive method of delayed primary wound closure. In a surgically prepared wound bed, covered with granulation tissue and free of infection, autogenous STSG can provide expedited closure with satisfactory outcomes.4,5 In cases in which autogenous STSG is not feasible, allogeneic skin grafting or orthobiologic dressings may facilitate definitive wound closure.
Key Considerations With Flap Closure
For complex diabetic foot wounds with exposed neurovascular structures and/or bone, consider flap closure. Local random flaps, such as rotational and transposition flaps, are indicated for defects with healthy adjacent skin. In certain clinical scenarios in which osseous deformities also require correction, rotational flaps are ideal in assisting with the definitive soft tissue closure.6 This reconstructive step provides the surgeon with the ability to simultaneously and directly access osseous structures for correction along with performing the wound closure technique.
Rotational flaps allow for mobilization of large areas of soft tissue through a wide arc of rotation for reconstruction. These local random flaps are advantageous because of their wide vascular base and thus have an excellent blood supply. The harvested flaps include the epidermis, dermis and subcutaneous tissue, and are based on geometrical designs. They are ideal for soft tissue coverage on the plantar surfaces of the diabetic foot by replacing soft tissue defects with similar and long-term durable soft tissue coverage.
Local muscle flaps for soft tissue coverage of the diabetic foot provide alternative reconstructive options when more complex wounds are recalcitrant to healing and the surrounding skin is compromised or not available as a donor site. In this reconstructive step, local muscle flaps provide excellent wound closure for diabetic foot wounds with concomitant osteomyelitis, exposed hardware and large resected soft tissue and/or osseous defects. The malleability of muscle allows it to eliminate dead space effectively while the dense capillary network facilitates antibiotic deposition and improves the local wound environment.7
The most common local muscle flaps for soft tissue reconstruction of the diabetic foot include the abductor hallucis muscle for medial and/or plantar medial wounds, the flexor digitorum brevis muscle for plantar central wounds, the abductor digiti minimi muscle for lateral and/or plantar lateral wounds, and the extensor digitorum brevis muscle for dorsal and/or dorsal lateral wounds.8
One can cover the harvested muscle with an autogenous STSG or orthobiologics while closing the donor site primarily. Thorough vascular examination and knowledge of the lower extremity vascular supply and anatomic variants are necessary before considering the use of a local muscle flap for soft tissue coverage of the diabetic foot and/or ankle.
Local and distant pedicle and/or perforator flaps are useful for closing complicated wounds in which closure is necessary over a weightbearing surface or when large soft tissue and/or osseous defects are not amenable to closure via local random or muscle flaps. The most common local pedicle flaps for soft tissue reconstruction of the diabetic foot include the medial plantar artery pedicle flap, which is ideal for cases of midfoot/hindfoot Charcot neuroarthropathy reconstruction, and the reverse flow sural artery neurofasciocutaneous flap for soft tissue reconstruction of major hindfoot/ankle defects. The advantage of a pedicle and/or perforator flap in patients with diabetes mellitus and multiple medical comorbidities is that the flap can provide extensive soft tissue coverage without the need for the microvascular anastomosis that is associated with free tissue transfers.9
Conventional neurovascular or fasciocutaneous flaps are connected to a source vessel(s) at the fascial level. A perforator flap is connected to vessels of the subdermal or subcutaneous plexus, which involve a connection to more distal vascularity than a conventional flap. Therefore, one can take thinner sections of tissue from the conventional donor sites of myocutaneous flaps.10
The use
of perforator flaps for soft tissue coverage of the diabetic foot and ankle are usually based on a distal perforator and raised as fasciocutaneous flaps. When it comes to perforator-based island flaps that have completely preserved source vessel(s), one can efficiently customize and tailor these flaps into different configurations required for definitive soft tissue coverage. Surgeons can cover harvested donor sites with autogenous STSG, allogeneic skin grafting or orthobiologics. The application of the perforator flap technique enables more precise dissection and ultimately expands the flap options for the reconstructive surgeon.11
Lastly, the use of free flaps may be indicated in certain clinical scenarios after the surgeon has attempted other reconstructive procedures and no other options are available for soft tissue coverage. Carefully consider patient selection, medical optimization and adequate vascular supply before using free flaps for plastic surgical reconstruction of the diabetic foot and ankle.
How To Manage Patients Postoperatively
Following major definitive soft tissue closure techniques such as the utilization of local, muscle, perforator, pedicle or free flaps, adjunctive application of circular external fixation can provide an excellent tool for simultaneous surgical offloading, equinus correction, flap immobilization, lower extremity stability, flap monitoring and osseous deformity correction if necessary. This podoplastic approach eliminates the risk of flap failure due to frequent shearing forces and weightbearing activities at plantar surfaces of the diabetic foot.
The postoperative management of reconstructive patients typically takes place in the hospital setting with the length of hospitalization based on the extent of the surgical reconstruction. Monitor flap viability closely and provide local wound care dependent on the technique(s) utilized. Ensure the duration and route of antibiotic therapy is based on intraoperative cultures and/or infectious disease recommendations. Physical and/or occupational therapy can begin in a progressive, controlled fashion to determine further rehabilitation requirements, allow for patient transfers, and facilitate subsequent non-weightbearing of the surgical lower extremity with the use of an assistive device.
After discharge from the hospital, the patient presents to the clinical setting for close observation of the flap and donor sites with serial plain radiographs to monitor alignment and stability of the circular external fixation and healing of any osseous reconstructive procedures. The timing of removal of the circular external fixation device depends on the podoplastic technique and/or concomitant osseous reconstructive procedures. Patients then transition to lower extremity splints and/or casts. They will subsequently proceed to a removable walker brace and accommodative shoe gear with assistive bracing as indicated when weightbearing is safe.
In Conclusion
Surgical management of diabetic foot and ankle wounds can be very challenging for the reconstructive surgeon. Maximizing patient outcomes through the delivery of quality care and treating each patient individually are keys to a successful outcome in plastic reconstructive surgery of the diabetic foot and ankle. There is no single solution for wound closure in the diabetic foot but having a plethora of treatment options to employ along with extensive surgical training may optimize outcomes for each patient.
Dr. Stuto is a Specialist and Fellow in Reconstructive Foot and Ankle Surgery within the Division of Podiatric Medicine and Surgery in the Department of Orthopaedics at the University of Texas Health San Antonio.
Dr. Ramanujam is an Assistant Clinical Professor and Chief within the Division of Podiatric Medicine and Surgery in the Department of Orthopaedics at the University of Texas Health San Antonio.
Dr. Zgonis is a Professor and the Externship and Fellowship Director in Reconstructive Foot and Ankle Surgery within the Division of Podiatric Medicine and Surgery in the Department of Orthopaedics at the University of Texas Health San Antonio. He is the Founder and Scientific Chairman of the Annual International External Fixation Symposium (IEFS) in San Antonio. Contact Dr. Zgonis at zgonis@uthscsa.edu .
References
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8. Stapleton JJ, Zgonis T, Jolly GP, Badekas T. Muscle flaps for soft tissue coverage of the diabetic foot. In: Zgonis T (ed): Surgical Reconstruction of the Diabetic Foot and Ankle, Ch. 13, Lippincott Williams & Wilkins, Philadelphia, pp.167-177.
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