Novel approaches

Figure 1. Treatment of the patient is a multi-disciplinary effort. It balances the tri-factor of aggressiveness, age and effectiveness of local control (a). In this way it may be determined if the patient will benefit from the proposed treatment option. It should be understood however that above all, the patient’s survival is not to be compromised. In this study conducted by the author reviewing the survival of patients with osteosarcoma over thirty years it is found that the survival of patients with osteosarcoma in the National University of Singapore was superior to the national average and that this in turn was superior to the national US average (statistically significant). Hence we may conclude that the treatment modalities offered to our patients in Singapore have not compromised their survival over the last 30 years.

Figure 2. It is rarely if ever necessary to perform an amputation in this era of modern medicine for bone tumors unless the tumor has fungated through the skin. This patient who had a neglected bone tumor and had sought a second opinion from a neighboring country was offered an amputation above the knee (a).We agreed that an amputation was necessary but offered the option of replanting the amputated segment using microsurgical techniques (b). We were able to re-anastamose all his vessels and his nerves which were lost in the amputated segment (a so called amputation replantation procedure). The huge advantage of this procedure is that the ankle now functions as a knee and can take a below knee prosthesis which is many times superior to an above knee amputation prosthesis (c). The variants of this procedure and how it compares to an above knee amputation (d) illustrate how this procedure may be superior over an above knee amputation.

Figure 3. This 4 year-old child had a Ewing’s sarcoma of the tibia (a). It had was about 15 mm from the growth plate (b). In view of her age, she was offered an amputation by her referring physician. Nevertheless we were able to offer her a limb salvage procedure after resecting the tumor (c). The only thing that would fit the dimensions of this toddler was the humerus of an adult (d). By doing an intercalary replacement, the author was able to save the growth plate (e). Surgery was uneventful and the epiphyseal screws were removed to allow growth (f). Six months later (g) the growth in the epiphysis was appreciable (arrowed).

Figure 4. Reusing the tumor bearing bone is an excellent solution to the challenges faced by tumors around the pelvis – in particular the hip joint. This 9 year-old boy had a Ewing’s sarcoma of the acetabulum (a). Resecting tumor (b) would result in an unstable joint and some surgeons would fuse the hip resulting in problems for the child sitting and causing long term back problems.  The author elected to preserve the joint by hyper-freezing it in liquid nitrogen (c) and replanting it. This gives a perfect match for size and anatomy. Unfortunately the process of freezing, while it still preserves the growth factors kills off the cells both normal and malignant. Hence rods and cement are used to re-enforce the structure. Two years later the patient walks with a limp but is able to perform functionally well. There has been no signs of recurrence.

Figure 5. The author has extensive experience in using endoprosthetics in the reconstruction of bone tumors. These work very well in teens and adults. This 42 year-old male had a sarcoma of the left distal femur (a). Following the biopsy the tumor was filled with cement and metallic rods to prevent any fracture while chemotherapy was initiated. After 2 months the entire segment was resected and a megaendoprosthesis was used to reconstruct the defect. Another case shows the segments of bone which the megaendoprosthesis attempts to replicate (d). While a convenient approach, in this study by the author financed by the National University of Singapore, it was found that physical satisfaction was only superior if the patients’ own joint can be preserved (e). Hence the main thrust in surgical approach at the University has been to preserve the joint where possible unless as in this case the joint cannot be preserved without endangering local control.

Figure 6. Professor Nathan led an initiative presently into the third phase of implementing cryosurgical ablation of tumors. The first phase involved ablation using liquid nitrogen pouring techniques. The second phase involved open procedures using the cryoprobe system shown (a). Presently we are developing minimally invasive technology using CT fluoroscopy to target the tumors in situ percutaneously (b). Each probe has a known and reproducible zone of ablation (c) which freezes down to -200 degrees Celsius. The process is monitored using thermocouples. It allows the percutaneous freezing of tumors without requiring large incisions (d).

Figure 7. By creating specialised and customised jigs 3D printed cutting guides allow very precise placement of cuts.

Figure 8. 3D printed implants very precisely fit defects created after tumor resections.

Figure 9. This is the video of a highly specialized resection and reconstruction of a bone tumor using 3D printing technology. Further information about this is available here.

Figure 2. The method proposed by us is to use a completely embedded bone distractor that is powered by electromagnetic induction.