Considerations surrounding reconstruction after resection of musculoskeletal sarcomas
ABSTRACT
The defects left by resection of bone and soft-tissue sarcomas often require reconstructive surgery to provide adequate wound coverage, preserve limb function, and optimize cosmetic results. Immediate reconstruction should always be considered after resection with a negative margin, and should be attempted whenever possible. The choice of reconstructive method and tissue flap depends on multiple factors, including body site, donor site morbidity, functional requirements, size of the vascular pedicle, and aesthetics. Preoperative planning before the resection should anticipate the defect size and resulting functional and cosmetic deficits; the success of such planning depends on a collaborative approach between the teams performing the primary resection and the reconstruction. Vigilant postoperative care and flap monitoring is key to avoiding flap or graft failure, hematoma, infection, and other reconstruction-related complications.
LOCATION-BASED WOUND RECONSTRUCTION
Musculoskeletal sarcomas can occur in virtually any region of the body, and myriad reconstructive options are available for various body sites. Since lower-extremity musculoskeletal sarcomas represent about 75% of cases,1 we will focus mainly on reconstruction of the lower extremity.
Factors driving choice of flap
Selection of an appropriate flap is essential to an optimal outcome. Flaps should be chosen with regard to donor site morbidity, functional requirements, length and diameter of the vascular pedicle, and aesthetic outcome.3 Usually physical examination, palpation of peripheral pulses, and Doppler ultrasonography are sufficient to evaluate the circulation. A preoperative angiogram should be considered in patients with severe peripheral vascular disease or previous trauma, which can potentially compromise the reconstructive outcome.15
Each region of the lower extremity possesses unique anatomic and functional characteristics that must be evaluated. It is useful to categorize the thigh, lower leg, and foot into separate anatomic units when planning reconstruction. We further divided these units into several subunits, as previously proposed by Sherman and Law15 and as outlined below.
Thigh
The thigh is usually well perfused and has several muscle groups, which facilitates reconstruction. Primary closure, skin grafts, or local flaps are acceptable options in most cases. The remaining musculature can be rotated or advanced to cover defects in the anterior or posterior thigh, providing bulk and adequate blood supply.
Hip and proximal/lateral thigh. Local muscle or myocutaneous flap options include tensor fascia lata, vastus lateralis, and rectus femoris flaps, all of which are based on the lateral circumflex femoral artery.
The tensor fascia lata flap is thin but has a long fascia extension that can be elevated from above the knee and can include a large skin paddle that is innervated by the lateral femoral cutaneous nerve. Some patients may experience knee instability after tensor fascia lata harvest.
The vastus lateralis muscle flap provides good bulk. Its arc of rotation reaches most of the inferior and posterior pelvis. It has little effect on ambulation.
The rectus femoris muscle flap is not so bulky, is easily mobilized, and has a wide arc of rotation. The donor site can be closed primarily. Harvest of this muscle can be associated with some strength loss during knee extension. For large defects of the upper third of the leg, a pedicled rectus abdominis muscle flap based on the deep inferior epigastric artery can be used. A vertically oriented skin island can be extended up to the costal margin, improving the reach. When the nature of the wound precludes use of pedicle flaps, free tissue transfer is indicated, with the latissimus dorsi muscle flap being used most commonly.15,16
Mid-thigh. Wounds in this location often can be closed with skin grafts or fasciocutaneous flaps. If the femur is exposed, however, a muscle flap will be required. As above, the tensor fascia lata, vastus lateralis, and rectus femoris can be used as flap options. If the lateral circumflex artery is unavailable, other flap options include the gracilis, vastus medialis, and rectus abdominis muscles. The gracilis muscle flap is based on the medial circumflex femoral artery and is useful for covering the medial aspect of the mid-thigh. Although this is a thin muscle, it can be used to cover long defects. The vastus medialis muscle flap is supplied by perforators from the profunda femoris and superficial femoral arteries. It can be rotated medially and advanced distally to cover patellar defects.
Supracondylar knee. The knee is a location where sarcoma resection is particularly likely to leave a defect with exposed bone, tendons, or ligaments that will need coverage. The gastrocnemius muscle flap combined with a split-thickness skin graft remains a consistent and reliable reconstructive option for this area. Other options are an extended medial gastrocnemius muscle flap or myocutaneous flap, which incorporates a random fasciocutaneous extension. For larger defects, free flaps should be considered, such as the anterior thigh flap, rectus abdominis muscle flap, or latissimus dorsi muscle flap. If tendons or ligaments need to be reconstructed, we favor autologous tissue, such as the fascia lata and plantaris tendons. These are easy to harvest and provide long-lasting joint stability.
Lower leg
Proximal third of the tibia. Defects here can usually be covered with a medial or lateral gastrocnemius muscle or myocutaneous flap, or a combination of the two. These muscles have a dominant vascular pedicle—the medial and lateral sural arteries. They can be harvested as an island for better reach, and they are reliable and have minimal donor site morbidity.15 The soleus muscle flap is another option that can be used alone or in combination with the medial or lateral gastrocnemius. Defects that are not amenable to closure by these flaps will most likely require free tissue transfer. The rectus abdominis or latissimus dorsi muscles are the first options. The latter can be combined with the serratus muscle if more bulk is needed.
Middle and lower thirds of the tibia. The soleus flap is frequently used for small or medium-sized mid-tibial defects. It is based on branches of the popliteal artery and posterior tibial artery. Larger defects require a combination of soleus and gastrocnemius muscle flaps or free tissue transfer.
Foot
Ideal reconstruction of the foot should provide thin and durable skin that will tolerate mechanical stress, and achieving this can be quite difficult. Skin grafts are seldom used for the foot, and are limited to non–weight-bearing portions with good underlying soft tissue.
Proximal non–weight-bearing areas (Achilles tendon and malleolar area). Local fasciocutaneous flaps are preferred. The lateral calcaneal artery flap, which is based on the peroneal artery branch, can cover exposed Achilles tendon, providing sensate coverage (sural nerve). The dorsalis pedis flap can be mobilized to cover the malleolar region and distal Achilles tendon, but donor site morbidity limits its use. Free tissue transfer is required for larger defects, and the the main options are flaps from the radial forearm, temporoparietal fascia, or lateral arm.
Heel and midplantar area. For heel reconstruction, the medial plantar artery flap, dorsalis pedis flap, abductor myocutaneous flap, peroneal artery flap, or anterior tibial artery flap can be used. The most versatile flap of the foot is the medial plantar artery flap, which is available only when the posterior tibial artery is intact. If local flaps are not suitable, microvascular tissue transfer is indicated. The radial forearm flap, scapular flap, lateral arm flap, or anterolateral thigh flap can be used. The radial forearm flap is usually the first choice because it is thin, has a long pedicle, and is easy to harvest.
If the foot defect is associated with a large cavity, muscle flaps are the first choices, specifically the gracilis or anterior serratus. A split latissimus muscle can also be applied. The full latissimus or the rectus abdominis are often too large for the type of defects observed.
Distal plantar area and forefoot. Most wounds in this region will require free tissue transfer. Free muscle flaps with split-thickness skin grafts provide the most stable and durable coverage.
Amputation vs limb salvage
It is important to evaluate the effects of lower-extremity salvage on ambulation. Salvage of a nonfunctional limb is of little value for the patient. Likewise, patients with severe medical problems may not be good candidates for limb salvage procedures. In those situations, amputation of the lower extremity is indicated. Adequate soft-tissue coverage and good distal perfusion are necessary to ensure healing of an amputation. If possible, local tissue rearrangement may be enough to provide a good amputation stump to fit an external prosthesis. In the case of radiation damage to the tissue, a free tissue transfer is necessary. The calcaneal-plantar unit from the amputated limb is frequently used as a free flap. Other flaps from the amputated limb, called fillet flaps, are harvested immediately and converted to flaps transferred to the defect site. Studies show that they are oncologically safe and reliable.17 Other flaps that provide good coverage for amputation defects are the latissimus dorsi muscle flap, the radial forearm flap, and the anterolateral thigh flap.
Upper extremities
