New surgical techniques
The decades since widespread adoption of limb-sparing surgery for
primary bone tumors have seen incremental improvements in the ability of
surgeons to remove tumors whilst maintaining as much function as
possible in the affected limb. In any procedure, surgeons and patients
must balance the oncological benefits of wider resections with the
morbidity of removing normal tissues, such as muscle, bone and nerves.
To achieve this, surgeons have to define the anatomic location and
extent of tumor to enable accurate complete resection. MRI remains the
gold standard to identify the intramedullary extent of primary bone
tumors, including skip metastases.100,123 Preoperative
imaging however, is unfortunately not able to assess the response of
tumors to neoadjuvant chemotherapy with sufficient reliability to
influence surgical options.124 Intraoperative imaging
techniques, such as fluorescence using indocyanine green, offer the
prospect of guiding surgeons towards improved surgical margins, but have
yet to be proven in large scale clinical trials.125Novel techniques including intraoperative navigation and personalized
custom jigs to guide bone resections, are becoming more established, may
increase safety, and when matched with implants using additive layer
manufacturing and porous ingrowth surfaces, offer the ability to improve
margins whilst preserving normal tissue, (Fig. 3).126
For some patients with large tumors where it may not be possible to
preserve the limb, or when the expected functional differences between
limb-sparing surgery and amputation are small and the risks of
limb-sparing surgery high, amputation remains the best option.
Reconstruction with the uninvolved part of the limb, for example, by
rotationplasty or tibial turn-up may be helpful, particularly in
children.127 Advances in prosthetics and other
technologies including transosseous fixation devices offer the potential
for improved function for some amputees.128
Limb preservation carries a risk of local recurrence. In OS,
retrospective studies have evaluated the risk in terms of the surgical
margins, chemotherapy response and proximity to major
vessels,129,130 but the application of these systems
in prospective decision making has yet to be established.
Growth and the long-term complications of surgical reconstructions are
further issues for adolescents. Growing endoprostheses contain a
mechanism which is activated in outpatients using a magnetic coil.
Although these implants have reduced the number of operations required
after endoprosthetic reconstruction, patients do not escape further
surgery, but the rate of limb preservation remains high. Bone-compatible
collars encourage bone growth onto the surface of implants and reduce
the risk of aseptic loosening when successful integration occurs. New
porous designs may have some advantages but these remain to be
proven.131 Antibacterial silver surface treatments
have also become widely adopted with the aim of reducing the risk of
deep infection. However, studies of their efficacy are retrospective and
they have not been subjected to a prospective randomized trial
.132