Dr Akshay Tiwari Best Musculoskeletal / Orthoepdic Oncologist in Delhi, India

Computer Navigation

Like all cancers, the focus is now not increased survival along with preservation of form and function as well. At most specialised sarcoma centres, more than 90 % of these patients undergo a limb sparing surgery (or limb salvage surgery), and amputations are very rarely required. This involves complete cancer removal along with a layer of surrounding normal tissue, and reconstructing the defect with a suitable means, most commonly prosthesis. Since complete removal of cancerous bone with an extra layer of bone as safety margins is curative, surgeons usually tend to err on the side of removing more bone rather than less, to be sure of complete disease removal. The two inherently contradictory attempts to remove extra layer of tissue for optimum cancer control and saving maximum possible bone for better function are the reason surgeons have to look for means to optimise both complete cancer removal but also saving not just limbs, but also joints and growth plates, if possible.

This is where computer navigation has come in as a breakthrough. This is a technology which enables the surgeon to exactly reproduce the precise surgical plan that is made preoperatively, making sure minimum bone needs to be removed and maximum form and function of the limb retained. As the MRI and CT scan images are loaded on to the software, the bone in question is registered (making it a map to be charted) and the instruments are calibrated, so as to give real time feedback on the placement of cutting instruments with respect to the tumor. This intra operative “GPS” gives the orthopedic oncologist the precision in placement of instruments on the bone reaching sub- millimetre accuracies. These instruments can then cut just the amount of bone that is required to be sacrificed for disease clearance, while retaining a lot of precious bone which would have been otherwise removed.

This potentially means that we can save more bone close to a joint, thereby avoiding joint replacement in a young patient, or even a growth plate of a young child, preserving the growth potential of the limb. Navigation also shows the surgeon critical structures like blood vessels and nerves in the vicinity of bone (particularly in cancers involving the bones of pelvis and sacrum), making these major surgeries safer and more effective. Giving the surgeon more confidence to make closer cuts, computer navigation has been shown to reduce bone loss, blood loss and operative time without compromising disease clearance. Hence, computer navigation is being seen as the next big thing in orthopaedic oncology surgery, which adds to safety and precision of these surgeries.

We are regularly and judiciously using this computer navigation, because our focus is not only on complete cancer removal but also on saving more bone for better function.