Offloading the Lateral Calcaneal Artery Flap: a Case Study Dr. Roger Drown DPM, Eric Temple DPM, Tim Holcomb DPM, Dr. Colin Pehde DPM

Iowa Methodist Medical Center and Des Moines University

Introduction

Case Study

References

Case Study

Conclusions

Literature Review Case Study

1. Baumeister et al. A Realistic Complication Analysis of 70 Sural Artery Flaps in a Multimorbid Patient Group. Plastic and Reconstructive Surgery 2003; 112: 129-140.

2. Bindiger et al. External Fixation of Extremity Flaps and Grafts. Ann Plast Surg 1991; 26: 198-199. 3. Byrd, H., Cierny, G., Tebbetts, J. The Management of Open Tibial Fractures with Associated Soft-Tissue Loss:

External Pin Fixation with Early Flap Coverage. Plastic and Reconstructive Surgery 1981; 68: 73-82. 4. Clemens et al. External Fixators as an Adjunct to wound Healing. Foot Ankle Clin N Am 2008; 13: 145-156. 5. Colen, L. A Realistic Complication Analysis of 70 Sural Artery Flaps in a Multimorbid Patient Group. Plastic and

Reconstructive Surgery 2003; 112: 141. 6. Hammer et al. Simplfied External Fixation for Primary Management of Severe Musculoskeletal Injuries Under War

and Peace Time Conditions. Journal of Orthopaedic Trauma 1996; 10: 545-554. 7. Horowitz et al. Lawnmower Injuries in Children: Lower Extremity Reconstruction. The Journal of Trauma 1985; 25:

1138-1146. 8. Noack, N., Hartmann, B., Kuntscher, M. Measures to Prevent Complications of Distally Based Neurovascular Sural

Flaps. Ann Plast Surg 2006; 57: 37-40. 9. Ramanujam, C., Facaros, Z., Zgonis, T. External Fixation for Surgical Off-Loading of Diabetic Soft Tissue

Reconstruction. Clin Podiatr Med Surg 2011; 28: 211-216. 10. Tukiainen, E., Seljavaara, S. Use of the Ilizarov Technique After a Free Microvascular Muslce Flap Transplantation

in Massive Trauma of the Lower Leg. Clinical Orthopaedics And Related Research 1993; 297: 129-134. 11. Zgonis, T., Stapleton, J. Review: Innovative Techniques in Preventing and Salvaging Neurovascular Pedicle Flaps

in Reconstructive Foot and Ankle Surgery. Foot Ankle Spec 2008; 1: 97- 104. 12. Stark, B., Zwirner, B., Blomqvist, L. Long-Term Results with the Proximally-Based Neurovascular Lateral Calcaneal

Flap. Scand J Plast Reconstr Surg Hand Surg 2003; 37:107-112.

Lawnmower accidents result in more than 80,000 hospitalized injuries in the U.S annually, with a large percentage of these injuries involving the foot and ankle of children under age fourteen. These injuries are some of the most devastating and disabling injuries treated by reconstructive surgeons. Successful management of these wounds requires a wide array of soft tissue reconstructive procedures and different offloading options7. Traditionally, treatment for lower extremity wounds with extensive soft tissue damage was amputation, however this increases energy expenditure, decreases life expectancy, and increases risk of amputation to the contralateral leg4. Due to the complexity of these injuries multiple operations are typically required by different specialties. Extensive soft tissue defects to the weight-bearing surface of the foot often require coverage with free flaps, muscle flaps, local flaps, or pedicle flaps in order to obtain durable long-standing wound closure11. Vascular surgery should be consulted to ensure blood flow to the dominant arterial branch of the flap is present. Pedicle flaps are defined as an isolation of an identifiable named neurovascular bundle supplying the block of tissue intended to be transferred11. Pedicle flaps can be fasciocutaneous, adipofascial, or musculocutaneous with either antegrade or retrograde blood flow and provide durable coverage to the plantar aspect of the foot. Failure of the flap to heal postoperatively results from repetitive shearing forces about a joint, decubitus pressure, noncompliance, venous congestion, or arterial spasm, with the most significant being the detrimental effect of motion on wound healing11. Innovative techniques to prevent or salvage compromised pedicle flaps are essential to long-standing wound closure. Offloading the pedicle flap is a critical part in the patient’s postoperative healing period. Numerous techniques have been used to limit pressure over pedicle flaps including; awkward positions in bed with pillows, modified posterior splints, and casting. Casting the knee in a flexed position prevents weight-bearing but doesn’t allow observation of the flap and can cause a partial knee flexion contracture and shearing forces at the flap. External fixation provides the surgeon with a means to elevate and offload the leg, increase stability, allow for osseous procedures, easy flap monitoring, and relieves pressure on the flap. Two types have frequently been used; the “kickstand” external fixator and the Taylor spatial frame. The use of external fixation to offload pedicle flaps allows for quick and repeated evaluation of the flap, while maintaining alignment of the foot and ankle to prevent kinking and avoid tension at the pedicle flap. The aim of this study was to assess the validity of external fixation use with soft tissue healing of pedicle flaps, through a case review.

The patient is a 20-year old female presenting to clinic with significant hyperkeratosis and fissuring on the posterior aspect of her right heel. There is a history of a traumatic lawn mower injury that ran over the back of her heel in 2004. At the time of injury, the patient suffered a complete laceration of her Achilles tendon and soft tissue lacerations. Multiple surgeries were performed by orthopedic and plastic surgeons to repair the tendon and cover the open wound. Within the six year span of initial presentation, at least ten revision surgeries were performed to obtain wound coverage, removal of scars and contractures. The previous surgeries obtained closure; however, the sites began to form fissures and ulcerate, which required hospitalization for redness, drainage, cellulitis, and non-healing wounds.

Upon examination, pain was noted to the posterior heel, where fissuring and callousing of the medial to central glabrous junction was present. The patient was sent for diagnostic angiogram of the peroneal artery to identify adequate flow of its terminal branches. After discussion with the patient and patency of the lateral calcaneal artery identified, she was taken to surgery in order to perform a revision of her scar and chronic ulceration. A lateral calcaneal artery flap with external fixation was performed. A doppler was used to trace the course of the lateral calcaneal artery from the distal aspect of the lateral malleolus to the plantar aspect of the heel. A template was used to measure out the flap to be transferred medially to cover the posterior heel. The flap was then meticulously dissected from the periosteum of the distal aspect of the calcaneus in a full-thickness manner. It was lifted from the calcaneus and contained the lateral calcaneal artery, sural nerve, and lesser saphenous vein. The flap was primarily closed utilizing 3-0 nylon in a simple interrupted fashion noting good apposition of the flap both plantarly and laterally. A wound VAC was applied noting no leaks and functioning properly. A 3-ring fixator was placed on the lower extremity, taking care to avoid all neurovascular structures. The patient was admitted after surgery for pain management and gait training. Post-operative evaluation revealed the fixator to be intact, no redness, significant discharge or signs of infection noted. The incision site on the lateral calcaneal artery flap showed signs of healing with minor dehiscence to the apex of the incision.

At 35 days status post-op the external fixator was removed, wound debrided and application of a sinus tarsi pinch skin graft was performed. A cast was place on the right lower extremity and was removed 10 days post op from the second surgery for evaluation. The lateral calcaneal artery flap was noted to be healing well; however, the full thickness pinch graft was mildly discolored, but intact. Steri-Strips were applied to the donor site and the distal aspect of the original flap. A fiberglass cast was reapplied in standard position holding the foot at 90 degrees. One week later, the cast and stitches were removed. She was transitioned into a cam boot and crutches at 31 days post second surgery and into normal shoe gear at 45 days. At 80 days post op, the patient was completely healed and released from care.

•Traditional offloading techniques are inadequate for healing of pedicle flaps located on weight-bearing surfaces •External fixation can be used to immobilize the lower extremity, and is an adequate method for offloading and observation of pedicle flaps •The lateral calcaneal artery flap is an excellent surgical technique for posterior heel defects that allows long-term durability because it does not sacrifice a major artery to the foot or ankle

Literature Review Traditional post-operative techniques used to limit pressure of flaps and donor sites have included awkward position in bed until fully healed, use of pillows, posterior splints with modifications, and casting modifications11. None of these techniques provide complete pressure relief, stable immobilization, positioning, or the ability for direct visualization of the flap and donor site. More recently, external fixation has had an established role for the reconstruction of soft-tissue defects in the lower extremities. This technique allows for offloading of a pedicle flap while immobilizing the affected extremity. Positioning the foot is paramount to avoid any tension at the site, to allow maximum healing potential11.

Recent literature has seen the use of external fixation solely to protect soft tissue reconstructions. Clemens et al. 4 described 12 patients that were unable to heal a weight-bearing soft tissue flap. All patients had failed conservative offloading measures at an average of 285 days. After frame application, mean healing time was 128 days, with an overall limb salvage rate of 83%. Literature has shown diabetic patient’s compliance to be 28% wearing an offloading boot, meaning the patient walks without protection to the extremity 72% of the time. External fixation forces immobilization and offloading of the affected limb. Another study by Baumeister et al. 1 conducted a retrospective review detailing complication rates associated with sural artery flaps in a multi-morbid patient population. The authors used external fixation devices in 28 of 70 flaps. The rate of necrosis in this group was 39% vs. 33% in patients without the device; the groups were too different to allow a statistical analysis. Regardless of this result, the authors recommend the application of an external fixation device in all patients except those with known peripheral arterial disease, with resting pain, as the device facilitates post-operative care while increasing patient mobility. Other authors have shown unfavorable outcomes in flap surgeries with co-morbidities including diabetes mellitus, PAD, vasculitis, and an age > 40 years old8. Patient selection for these surgical interventions is important, and an emphasis with mandatory pre-operative angiography to determine patency of the artery in question is essential8. Multiple small case reports have been performed on the lateral calcaneal artery flap. One of the largest reports, a long-term study of 8 patients, looked at functional outcome and flap failure 3-5 years post-operatively without utilizing any external fixation12. At mean follow-up of 40 months, no flaps had broken down, and five of eight patients were able to wear normal shoes. This flap carries protective sensitivity which is easy to harvest, has a low complication rate, and permits the wearing of normal shoes in most cases without the risk of skin breakdown. Chung et al.13 reported on five patients who underwent the lateral calcaneal artery flap. All five flaps survived with no breakdown in the grafted skin, even after wearing normal shoe gear. Since these flaps do not require the sacrifice of a major artery to the foot or leg with minimal morbidity to the donor site, this technique can be utilized for posterior heel soft-tissue defects providing durable wound closure. External fixation has been shown to be advantageous to post-operative soft-tissue flap healing. Patients with the co-morbidities above have shown improved healing potential with the use of external fixation due to immobilization and off-loading of the surgical sites. While both studies cited on the lateral calcaneal artery flap did not use external fixation and showed favorable results, our patient had an unusual presentation. Due to the complexity of the patient’s previous ten surgeries, the external fixation device was paramount for complete wound healing.