20 December 2021, Monday

 What is Limb Salvage Surgery?

Limb salvage surgery’ means saving the limb while effectively treating the malignant bone tumour affecting it. Until about 35 to 40 years ago, the only treatment for primary bone cancer in the extremities (limbs) was an amputation.

Even after such a radical treatment, the survival of these patients was poor; only about 20 to 25 % of these patients survived at five years from the time of treatment. Limb salvage surgery in these patients was an unrewarding experience due to several factors, chief among which were:

• The survival of these patients was very poor. Limb salvage surgery did not offer any survival benefits; in-fact it actually increased their risk of disease recurrence (for reasons mentioned in the next point), which in turn lowered the already dismal survival of these patients
• Surgery lacked precise planning as cross-sectional imaging technology (like MRI and CT scan) was not available. There was always a high risk of leaving behind disease tissue, or contamination of surgical field with tumor cells during the surgery. This resulted in a high risk of local recurrence of disease following Limb Salvage Surgery. Local recurrence of disease in sarcomas (even today) is clearly associated with a much higher risk of distant relapse (metastases) and therefore, a poor prognosis.
• Reliable ‘joint replacement’ technology was still in early stages of development.

In the 1970s and early 1980s, simultaneous breakthroughs in multiple areas of medical research and development brought about a revolution in the management of extremity bone sarcomas and firmly established Limb Salvage Surgery as the standard of care in the treatment of these enigmatic tumors.

Some of these important developments were:

• Medical oncology: At this time, the powerful role of chemotherapy in the management of some of the common bone sarcomas became clear. It brought about a dramatic improvement in the survival of these patients from 20-25% to 60-80%.
• Imaging technology: MRI and CT scan, which give excellent sectional views of the body (on which the planning of the Limb Salvage Surgery depends heavily), became available. With this technology, the margins of surgery could be planned with a high degree of accuracy and therefore limb salvage surgeries became reliable and safe.
• Joint replacement technology: Joint replacement implants and surgical techniques, revolutionized the treatment of some of the major disorders of the hip and knee joints. This same technology was extended to address the issue of managing the loss of bone and joint following Limb Salvage Surgery for bone sarcomas. To replace the surgically removed bone and joints, high quality implants and artificial joints were developed using special metals, alloys, etc.

Nevertheless, the situation here has changed in the past few years. Now, with indigenous technology, affordable, high quality and durable tumor endoprosthesis (metallic medical devices used as replacements for bone and joint) including total knee replacement implants have been developed and made available, offering excellent skeletal reconstruction options following these

surgical procedures for malignant bone tumors, providing the patient with a good functional outcome, despite the loss of large segments of bone and joint. These have been used in a large number of patients with excellent results.

Although megaprosthesis is the backbone of Limb Salvage Surgery, it does not mean Limb Salvage Surgery is not possible without the use of these implants. There are situations where only a Wide Excision of the diseased bone is sufficient.

This is true when the disease affects relatively unimportant parts of some bones (which are not absolutely vital for normal function), e.g. the shaft of the fibula, the distal part of the ulna, etc. Other reconstruction options are also available, following wide excision of bone and bone segments, to restore useful function in the affected extremity.

These include the use of autograft bone (bone graft harvested from the patient’s body), vascularized fibula autograft, allograft (donated human bone from a tissue bank), bone graft substitutes, local bone transports, Ilizarov technique, ECRT, etc. These are called as biological reconstruction options.

It is important to know that generally, whenever a feasible biological reconstruction option is available, it is preferred over the use of metallic tumor endoprosthesis, as in the long run they provide more durable results.

Further Reads:

1. What is grading of the response to the Neo-Adjuvant Chemotherapy?

2. What is Limb Salvage Surgery?