Surgical considerations

Limb salvage versus amputation requires a number of considerations. 

In the upper limb, single nerve sacrifices are compensable with tendon transfers. In the lower limb sciatic nerve sacrifice is compensable with ankle-foot orthoses. Antecubital and popliteal fossa tumors portend major neurovascular involvement and should be considered for amputation. The foot is especially tricky. Foot sparing surgery must ensure a sensate foot. Tibial nerve sacrifices necessitate amputation as below knee prostheses are more functional than insensate feet. 

Vessel bypasses are at considerable risk with chemotherapy or radiation therapy. The lack of soft tissue coverage may necessitate amputation. 

When soft tissue tumors abut bone, special problems arise. Bony resection entails considerable morbidity. Periosteal resection increases risk of pathological fracture and requires multimodality therapy (radiation, chemotherapy, surgery). 

Low grade sarcomas look like normal tissue under the microscope. This poor delineation of margins results in high risk of local recurrence. Dedifferentiation of tumors into a worse grade does happen with relatively benign looking tumors. 

Lymph node metastasis are uncommon and nodal dissection not routinely recommended. We employ the technique of sentinel node biopsy in nodal-metastasis prone tumors namely synovial sarcomas (in only 10%), rhabdomyosarcoma and melanomas.

Margins are the most important surgical consideration in soft tissue sarcomas. Positive margins are associated with 80% local recurrence. Marginal resections result in 20% local recurrence. Wide resections give about 10 % local recurrence. Radical resections have a 5% local recurrence rate. There is no difference in survival between limb-salvage and amputation. There is, however, a slightly higher incidence of local failure with limb-salvage.

Unplanned excisions represent a “no-man’s land” in terms of evidence-based medicine and are covered elsewhere in this website. They usually require re-excision as the are associated with 15% positive margins.

Figure 1 (video). The case is a soft tissue sarcoma of the thigh. This presented as a tumor in the sciatic nerve which was resected intraneurally using a microscope. The patient did not have any neurological deficit and a well-centralised spot of sarcoma was fount surrounded by benign tissue.