Can Sural Fasciocutaneous Flaps Be Effective in Patients Older Than 65?

Abstract

Background

Many studies have evaluated the reverse sural fasciocutaneous flap for coverage of wounds on the distal lower extremity, and many of these have focused on younger, healthy patients. However, to our knowledge, there has been no dedicated study focusing on older patients. We believe there is a generalized concern about performing these procedures in older patients because of microvascular changes associated with aging.

Questions/purposes

(1) What is the likelihood of flap survival in a small series of patients older than 64 years who underwent reverse sural artery fasciocutaneous flap for coverage of lower extremity wounds? (2) What additional procedures did patients undergo after treatment with this flap?

Methods

From 2009 to 2018, we identified 16 patients, 64 years or older, who underwent a retrograde sural fasciocutaneous flap. Patients were a mean (range) age of 71.5 years (64 to 87). The average size of the flaps was 30 cm² (range 12 to 64 cm²). The reverse sural artery flap was indicated when the skin could not be closed primarily and there was not a suitable vascularized bed of tissue for a split-thickness skin graft. All patients underwent a wide-based pedicle (3 cm to 4 cm), reverse sural artery fasciocutaneous flap with all but one completed in a “flap delay” manner, between 2 to 7 days, and without the use of microsurgery or doppler. Thirteen flaps were done to cover wounds that occurred over fractures while three were performed to cover chronic wounds. We performed a retrospective review of the electronic health record to ascertain patient comorbidities, age, timing of coverage, and size of the wound.

Results

In all, 94% of flaps (15 of 16) survived with 100% viability. One flap had 30% skin necrosis at the distal tip. The flap ultimately healed with in-office wound care, and epithelization occurred over the intact fascia. A total of five additional procedures were performed in five patients. Although the flap ultimately healed, an 87-year-old patient with partial flap necrosis ultimately elected for below-knee amputation for a persistent tibial infected nonunion. Another patient, despite a healed flap, eventually underwent a below-knee amputation 3 years later for a chronic osteomyelitis present before undergoing the reverse sural flap. One patient developed a pseudomonal infection of their Gustillo-Anderson IIIB open tibia fracture, resulting in a surgical procedure for débridement, after which the flap healed. Two patients underwent underlying hardware removal to relieve wound tension and allow for complete flap healing. No patients underwent further coverage procedures.

Conclusions

In this small series, we found fewer complications than have been observed in prior studies, despite our series consisting solely of higher-risk, older patients. We believe this may have been attributable to the period of delay before placing the flap, which has been previously associated with higher flap survival and which allows for an extra recipient-site débridement. We believe this procedure can be performed by appropriately trained orthopaedic surgeons because it does not need microsurgery.

Level of Evidence

Level IV, therapeutic study.

Introduction

The distally based, reverse sural fasciocutaneous flap can be used to cover wounds around the distal tibia, ankle, and foot. It relies on the retrograde flow of the sural artery, which runs with the sural nerve and lesser saphenous vein. This small artery collateralizes with the peroneal artery via segmental perforators, the most distal of which is approximately 5 cm from the tip of the lateral malleolus [4]. It was initially described in the early 1980s by Ponten, Donski, and Fogdestam. The technique’s description would undergo multiple iterations and improvements over the decades following its initial explanation. Since then, surgeons have developed techniques to improve its success, including preserving 2 cm to 3 cm of the perivascular tissue and introducing a delay during the flapping process [3, 8, 12].

Many studies have raised concerns about performing this procedure in older patients because of the reliance on the retrograde flow of the small sural artery in the distal leg and the microvascular changes present in the older patient [1, 2, 10]. However, there have been no dedicated studies looking specifically at the results of this procedure in older patients. Also, many of the prior studies included multiple techniques, such as narrow pedicles or no delay alongside patients with delays and wide pedicles, making interpretation difficult. Despite these prior studies issuing caution using this method in older patients, it is our belief that this is a reliable and effective method of obtaining soft tissue coverage over wounds on the foot and ankle region in geriatric patients.

We therefore asked (1) What is the likelihood of flap survival in a small series of patients older than 64 years who underwent reverse sural artery fasciocutaneous flap for coverage of lower extremity wounds? (2) What additional procedures did patients undergo after treatment with this flap?

Patients and Methods

Study Design and Setting/Participants/Study Subjects

In an institutional review board approved, single-surgeon, retrospective study, we queried our hospitals electronic health record (EHR), to identify all patients with a 65-year difference between their operative year and their birth year, who underwent a sural fasciocutaneous flap performed by the senior author (GLD) for wounds in the distal leg and ankle region. This method was used to identify those patients who were eligible or would become eligible for Medicare the calendar year of their surgery. We evaluated the EHR for age and comorbidities including smoking, peripheral arterial disease, venous insufficiency, diabetes, as well as timing of coverage, size and cause of the wound, outcome and any subsequent coverage procedures. We identified 16 patients within this age range who underwent this procedure between July 2009 and February 2018, the time senior author (GLD) has been at his current institution. The senior surgeon (GLD) did not perform any saphenous fasciocutaneous flaps, propeller flaps, or free-tissue transfers within this age group during this period; this represents all the lower extremity soft tissue flap procedures performed in this age range during the study period by the senior surgeon. Patients were a mean (range) age of 71.5 years (64 to 87). The average flap size was 30 cm² (range 12 to 64). Nine patients had no risk factors. There was an average of two risk factors present in patients with identifiable risk factors. One patient was an active smoker, another had a history of smoking, seven patients had culture-positive infections, three had insulin-dependent diabetes, seven had obesity, and one had peripheral artery disease. Thirteen flaps were performed to cover wounds that resulted over fractures or exposed implants. Three other flaps were performed to cover wounds; two wounds had broken down over the Achilles tendon after tendon repair and one was a chronic wound over the anterior tibia that occurred after the removal of squamous cell carcinoma. Of the 13 fractures, five were open distal tibia fractures, three were open tibia shaft fractures, three were open ankle factures, one was an open ankle and talar neck fracture, and one was a closed ankle fracture that developed an infection. At a minimum 1 year, no patient had been lost to follow-up.

All patients were referred to the senior author (GLD) for soft tissue coverage of wounds on the distal lower extremity. Patients in this study were selected for reverse sural artery flaps based on clinical evaluation and adherence to the standard principles of the reconstructive ladder. When the skin could not be closed primarily, and there was not a suitable vascularized bed of tissue for a split-thickness skin graft, the surgeon considered tissue transfer, including the reverse sural artery flap. The author’s current indications for staging flaps include flaps > 100 cm², flaps from the proximal third of leg needed for coverage of foot wounds, and flaps for patients with vascular comorbidities such as diabetes, and in this instance the microvascular disease of aging. Although he had experience performing other pedicled flaps, the senior author (GLD) performed no other rotational flap procedures in patients 64 years or older for comparison. Traditional risk factors, including age, smoking status, obesity, diabetes, peripheral vascular disease, or number of comorbidities, were not considered in selecting patients for this procedure, only whether sufficient tissue was available to cover the defect.

Description of Experiment, Treatment or Surgery/Variables, Outcome Measures, Data Sources, and Bias/Statistical Analysis, Study Size

The senior author (GLD) performed all flaps, and all but one flap completed in a sural flap delay technique. During the initial surgery, the surgeon assessed the recipient site, measured flap size, and repeated irrigation and débridement. The appropriate pedicle length was based on a reflection point approximately 3 to 4 fingerbreadths from the tip of the lateral malleolus; no doppler was used in identifying this site because we have found it to be a reliable anatomic structure. A thigh tourniquet was used with gravity exsanguination to facilitate visualization of the lesser saphenous vein. A zigzag incision was made over the proposed pedicle where the lesser saphenous vein was identified. The appropriately sized flap was then elevated while maintaining a 2-cm proximal skin bridge. A 3-cm to 4-cm cuff of perivascular tissue around the lesser saphenous vein, sural artery, and sural nerve was maintained. The sural fascia was elevated and cauterized across the lesser saphenous vein and the sural nerve under the proximal skin bridge. After the flap was well skeletonized, the surgeon loosely closed the incision with staples, applied a soft sterile dressing, and deflated the tourniquet. The limb was immobilized in a well-padded plaster splint, and the patient was not permitted to bear weight on the operated limb. In most instances, the flap was then completed and inset 2 to 7 days later, on either an inpatient or outpatient basis. The donor site was covered with a split-thickness skin graft and bolstered. There was no use of doppler or angiographic studies, nor microsurgery. We did not use drains, nor did we perform flap perforation for hematoma drainage. No anticoagulation was used. The limb was then dressed with soft dressings and placed in a plaster splint. The flap and donor sites were then examined in clinic weekly until satisfactory healing achieved. Flap success, defined as having blanchable skin with capillary refill, the lack of eschar, and the ability of the skin of the flap to be sealed to the surrounding skin at the time of suture removal, was assessed by the performing surgeon and the referring surgeon. This was further supported by whether or not additional procedures were needed to achieve soft tissue coverage. No other measures including doppler or angiographic studies were used in evaluating success.

Within the studied demographic, patients 64 years and older, the senior author (GLD) performed no other coverage procedures for comparison. All patients were followed until flap healing or a minimum of 1 year. The median (range) follow-up was 18 months (12 to 36). No patient was excluded for any reason.

Results

In all, 94% of flaps (15 of 16) survived with 100% viability. One flap had 30% necrosis at the distal tip. This eventually healed with in-office and home wound care allowing for epithelization over the viable fascia of the flap.

A total of five additional procedures were performed in five patients. The patient with the partial flap necrosis achieved coverage over their tibial shaft with local, in-clinic wound care but later elected to undergo a below-knee amputation secondary to a persistent infected tibial nonunion. Another patient, despite a healed flap, underwent a below-knee amputation 3 years later for a chronic osteomyelitis present prior to receiving a reverse sural flap. A third patient developed a pseudomonal infection of their Gustillo-Anderson IIIB open tibia fracture, resulting in surgical débridement, but the flap eventually healed. Two patients underwent underlying hardware removal to relieve wound tension and allow for complete flap healing. No patient underwent further surgery for flap contouring or debulking. All but the two patients who underwent amputations were able to return to normal shoe wear.

Discussion

Background and Rationale

The reverse sural artery flap was initially described as an alternative method of providing soft tissue coverage to wounds around the ankle and foot when local tissue was not sufficient and before moving up the reconstructive ladder to a free-tissue procedure. We believe this method is an often overlooked technique in the elderly as previous studies have shown higher than desirable complication rates in this population. Prior studies focused on slightly different techniques (narrow and wide perivascular cuffs, no delay, sural flap delay, and delayed sural flap procedures all within the same study). In this retrospective study, all patients underwent a fairly standardized technique with 15 of 16 flaps healing with 100% viability, and five patients undergoing subsequent procedures. To our knowledge, this is the largest reported on cohort to undergo reverse sural flaps with a 2- to 7-day delay and wide perivascular pedicle. Due to different techniques employed within other studies and other factors such as patient comorbidities and flap size, it is difficult to make direct comparisons with other studies; regardless, we believe our results show this can be a reliable method for covering wounds around the foot and ankle in older patients and fills a void within the orthopaedic evidence.

Limitations

The most important limitation in this study was selection bias. This flap was used when the skin could not be closed primarily and when there was not a suitable vascularized bed of tissue for a split-thickness skin graft. Although he had experience performing other pedicled flaps [11], the senior author (GLD) performed no other rotational flap procedures in patients 64 years or older to provide for a comparison. We recognize that other surgeons may use other flaps in this region; also, patients may have been referred elsewhere for soft tissue coverage. Assessment bias is another limitation in this single-surgeon study, although we believe this is largely controlled for with the binary nature of flap survival and number of additional procedures performed. Similarly, we made no attempts to assess pain, function, or patients’ views of the outcomes as the information available to us within the electronic health system provided no reliable way of assessing such outcomes. Instead, we focused on hard endpoints that were easily identifiable within the record. Survival was defined by whether or not additional procedures were needed to achieve soft tissue coverage. Despite the risk of selection and assessment bias, we believe our results show that this can be a successful procedure in patients older than 65 years.

Flap Survival

We found that reverse sural artery fasciocutaneous flaps, performed in older patients for coverage of lower extremity wounds, were likely to survive intact. This is in contrast to prior studies that have demonstrated higher flap losses in this age group [1, 2, 10]. In a retrospective review of 58 reverse sural artery fasciocutaneous flaps, nine major complications (three total losses and six partial losses) and 17 minor complications were encountered [10]. Advanced age (> 70 years), smoking, obesity and peripheral artery disease were identified as risk factors for flap complications. In a secondary outcome, they were able to demonstrate that flap procedures with a delay improved flap survival in those with comorbid risk factors [10]. Within their study, it was up to the discretion of the performing surgeon on whether or not to perform a “delay” procedure, and they did not report the number of patients who underwent a delay. We suspect the difference in the number of complications seen between their cohort and the one presented here may be related to the higher use of a 2- to 7-day delay procedure.

Additional Procedures and Complications

In this small series, a total of five additional procedures in five patients were performed after the surgery for the flap. One large review of 70 patients, with a mean (range) age of 54.1 years (13 to 92), who underwent reverse sural artery flaps, 59% experienced a complication defined as partial tip necrosis (12 patients), complete necrosis (13 patients), infection (five patients), hematoma (two patients), unresolved osteomyelitis (two patients), and delayed healing (four patients); ultimately, 38 patients underwent surgical revision [1]. In contrast, within our cohort we had two patients with delayed healing who underwent underlying hardware removal to achieve complete flap healing (age 86 and 67 years; both without comorbidities), and one patient (age 69, the lone smoker) with a Gustillo-Anderson IIIB open tibia fracture who underwent irrigation and débridement for a pseudomonal infection before fully sealing the flap to the surrounding tissue and healing the tibia fracture. In the comparative study, only four of the 70 flaps underwent a delay procedure. In contrast, the delay was a standard component of our reverse sural artery flap procedure, regardless of patient condition or comorbidities. We credit this success to the liberal use of the 2- to 7-day sural flap delay, which allows for an extra recipient site débridement and is believed to allow the depletion of catecholamines and further establishment of retrograde flow to the flap through vasodilation and vessel recruitment. The skin bridge allows for local support to the skin of the tip of the flap through the random vascularity of the skin [3, 5, 6, 8].

Conclusions

In this series, we found 15 of 16 flaps survived with 100% viability; the one that did not eventually healed without further surgical intervention. There were five subsequent procedures performed for five patients. These were not related to viability of soft tissue coverage but rather to the patients’ underlying disease. We found fewer complications than in prior studies, even though our series including higher-risk older patients. We believe this may have been attributable to the period of delay, which has been associated with higher flap survival in prior studies [3, 7, 9]. We believe this is a procedure that can be performed by appropriately trained orthopaedic surgeons because it does not need microsurgery. Future studies could evaluate this technique among more surgeons of varied experience to remove surgeon bias. We advocate that the reverse sural artery flap can be reasonably considered when contemplating soft tissue coverage for a wound around the foot or ankle in patients older than 65 years when local tissues are insufficient.