BURN CARE AND PREVENTION JOURNAL

KEY WORDS: Amputation stump, Free flaps, Lower limb salvage, Stump reconstruction

INTRODUCTION
Preservation of extremities presents a difficult challenge for reconstructive microsurgeons. Patients with unhealed amputation stumps have generally poor vascular condition due to vasculopathies or crush injuries. Tendons and bones are superficial and covered with a thin skin, and the amputation stump should be revised or changed to a more proximal level. Because the local tissue sources are insufficient for reconstruction in the distal extremity, free microvascular tissue transfers are the primary choice for reconstruction in many trauma centers as the source for required tissue.¹

Although there are a wide range of flap options, such as muscle flaps, musculocutaneous flaps, perforator flaps, and fasciocutaneous flaps, there is not a gold standard of free-flap selection in this area.² The decision is generally based on consideration of the patient’s vascular status and a surgeon’s expertise and preferences. In this study, we aimed to investigate the reasons for selection of recipient vessel and flap based on retrospective data of lower extremity salvage procedures at a single institution.

MATERIALS AND METHODS
Patients who underwent free-flap reconstruction from January 2020 to April 2023 at the Baskent University Department of Plastic, Reconstructive and Aesthetic Surgery for their unhealed or complicated amputation stumps in their lower extremity were reviewed retrospectively. The principles of the Declaration of Helsinki were followed for all patients. There were 10 patients (9 male, 1 female) included to the study. The vascular conditions of the patients were evaluated with Doppler ultrasonography and computed tomography angiography. Patients received 5000 U low-molecular-weight heparin twice a day for 1 week. Mobilization was not allowed for 1 week. Mobilization was initiated on postoperative day 7. Patient demographics, etiology of the amputations, location of the defects, flap type, recipient vessels, anastomosis fashion, early and late complication rates, and hospitalization length of stay were noted (Table 1).

RESULTS
The average age of 9 men and 1 woman was 58 years (range, 26-85 y). The locations of the defects were on the foot plantar region in 4 patients, foot lateral region in 2 patients, and calcaneus in 1 patient. The etiology of the wounds was diabetic limb in 9 of 10 patients, and 1 patient had electric burn history. Six patients had unhealed transmetatarsal amputations. Four patients had unclosed multiple finger amputation stumps. Free-flap selections were anterolateral thigh flap, latissimus dorsi musculocutaneous flap, vastus lateralis flap, and thoracodorsal artery perforator flap (Figure 1, Figure 2, and Figure 3).

The recipient vessels for free-flap anastomosis were anterior tibial artery in 6 patients, dorsalis pedis artery in 3 patients, and posterior tibial artery in 1 patient. End-to-side anastomoses were performed in patients with finger amputation stump defects, and end-to-end anastomoses were preferred in patients with unhealed transmetatarsal amputations. No complications were seen in 9 patients whose flaps all survived and the extremity length was preserved. The flap did not survive in 1 patient, and 1 patient was referred to the orthopedic department for below-the-knee amputation.

DISCUSSION
Amputation is a treatment method for severely damaged extremities due to trauma or ischemic-necrotic conditions. Amputation is performed at the level that provides the most healthy stump. Amputation level can be changed to a more proximal level when the stump exhibits healing problems. However, changing the amputation level may have several disadvantages. The energy consumption and cardiac load increase.³ Social isolation in addition to psychological consequences of an extremity loss carry the potential of a decreased quality of life. It has been established that life expectancy statistically decreases in patients with high-level amputations compared with lower-level amputations.⁴ Thus, a maximum effort should be performed to preserve the amputation level and length of the extremity.

Soft-tissue reconstruction of an amputation stump includes use of a flap from the amputated distal part, a local flap, or a free flap.⁵ Flaps obtained from the amputated limb are called “fillet flaps.”⁶ However, our patient cohort were patients with diabetic limb and had progressive necrosis due to ischemia and therefore were not candidates for fillet flap. Although local flap options are restricted, free microvascular tissue transfers can provide the required tissue to cover the extremity defect or unhealed amputation stump. The type of flap for reconstruction is decided according to the type of defect, the recipient site distance, vascular condition of the recipient vessel, and infectious environment. We preferred longer pedicle flaps such as anterolateral thigh, thoracodorsal artery perforator flaps in closure of finger stumps.

The selection of muscle or fasciocutaneous flaps has been a subject of debate for many years. Muscle flaps are superior to perforator, fasciocutaneous flaps because of their resistance against infections, higher ability to build up a new vascular network, and increased vascularity according to the “nutrient flap” concept.^7,8 In 1 patient with severe osteomyelitis, we preferred latissimus dorsi flap for infection treatment.

Piper and colleagues reported a preference for muscle flaps due to the associated reliable and robust blood supply, as well as the ability to contour muscle flaps around irregular stumps.¹ In contrast, Hallock reported that muscle and/or musculocutaneous free flaps are susceptible to atrophy.⁹ With advances in perforator flaps, a greater diversity of choices for skin flaps has become available to fulfill a similar role. Also, muscle preservation has been advocated by several authors for future ambulation and rehabilitation.¹⁰ Thus, our preference was a muscle-preserving fasciocutaneous anterolateral thigh flap, which has been a workhorse flap in past decades.

The superiority of muscle flaps over perforator, fasciocutaneous flaps is characterized by resistance of muscle flaps against infections, better ability to build a new vascular network, and increased vascularity according to the nutrient flap concept.¹¹ In 1 patient with severe osteomyelitis, we preferred latissimus dorsi flap for infection treatment.

Hahn and colleagues suggested either computed tomographic angiography or conventional angiography to detect and evaluate recipient vessels before reconstruction, to be treated with culture-directed antibiotic therapy according to infectious disease medicine recommendations.¹² Similarly, we investigated the vascular condition with both Doppler ultrasonography and angiography. The nephrological status of the patients should be well documented before angiographic tests are performed.

Lumley and colleagues⁵ emphasized that preserving the best possible flow for the foot reconstruction can be critical because main arteries are frequently occluded. Therefore, when using the major vessels as a recipient artery, it is necessary to preserve the distal flow by making an end-to-side anastomosis.¹² Our experience was similar to the experiences reported in the literature. We believe that end-to-side anastomosis has advantages to observe the reverse flow and without interruption of the distal flow. We prefer the end-to-end anastomosis when the distal end of the axial artery is close to the stump.

Although there is no definite information about the ideal starting date for prosthesis and ambulation, there are several approaches used by authors in previously published studies. Lumley and colleagues reported that a standard protocol for postoperative care involved a short period of immobilization, followed by the initiation of mobilization on postoperative day 5 in the majority of patients, and then followed by a gradual increase in ambulation starting with partial weight bearing until maximal restoration of normal gait is achieved.⁵ Hahn and colleagues stated that most patients could start to walk 2 months postoperatively, except for 2 patients who required additional operation for marginal flap necrosis.¹² Tukiainen and colleagues started prosthesis 10 weeks postoperatively after stump reconstruction.¹³ In our series, we immobilized patients for 1 week after tissue transfer. We started early passive motion rehabilitation on postoperative day 8. We generally refer patients to physical treatment after hospital discharge.

CONCLUSIONS
Our study showed free microvascular tissue transfers can preserve the limb length by covering bones, tendons, and unhealed previous amputation stumps.

Volume: 3 Issue: 1 March 2023

FULL TEXT