Tumour treatment using icotec’s Carbon/PEEK implants – striking out on new paths
The non-metallic VADER® spinal system made from carbon fibre-reinforced PEEK (Carbon/PEEK) offers new opportunities in radiotherapy for spinal tumours.
The radiolucent Carbon/PEEK material ensures both artefact-free CT/MRI imaging and therapeutic radio-transparency. This facilitates correct dose-planning, radiotherapy and follow-up control of spinal tumours and metastases over time.
Up to 40 per cent of all cancer patients will develop a tumour in the spine, and the spine is the most common location for skeletal metastases (Singh et al., 2006). In the decision for surgical treatment, decompression and stabilisation of the spinal column is paramount. Depending on other clinical factors, removal of the tumour will also be considered. For pain control and local control of the tumour, supplemental radiotherapy is often applied postoperatively.
However, when metal spinal implants are present, they will cause significant artefacts on the planning images. These artefacts make it more difficult to delineate anatomic structures during radiation therapy planning and correctly calculate the proper dose distributions. In contrast to metallic implants, icotec’s Carbon/PEEK implants cause only minimal imaging artefacts, enabling a precise demarcation of the tumour and planning of the doses in radiotherapy. The time-consuming manual corrections known from metallic implants are not required anymore.
Many years of clinical use of Carbon/PEEK implants have demonstrated their equivalence to metallic systems in spinal surgery (Külling et al., 2013; Benneker et al., 2014). Since the introduction of Carbon/PEEK pedicle screws, the use of the technology in the course of spinal tumour treatment has led to increased attention among surgeons and radiation oncologists.
During radiotherapy, metal implants will shield remaining tumour cells from the radiation and/or cause scattered radiation into the surrounding tissue and organs. Patients with metal implants must in some cases be excluded from curative proton therapy. In contrast, Carbon/PEEK implants allow the radiation beam to pass unimpeded through the Carbon/PEEK material into the initially planned tumour tissue, without shielding or beam scattering. This minimises the risk of a radiation dose that is either too high or too low, and thereby protects sensitive tissue.
The same positive properties of Carbon/PEEK material will remain relevant for imaging during clinical follow-up monitoring. Minimised imaging artefacts will allow the doctor to investigate the zone around the treated/removed tumour in greater detail and to thoroughly check for possible changes (recurrences).
Unobstructed diagnostic assessment of relevant anatomic structures such as the spinal canal, the neural foramen or the implant position will remain possible over time in the absence of imaging artefacts. This was shown via CT and MRI studies in the laboratory (Kilian et al., 2014) and in the patient (Eicker et al., 2014). Experiences with Carbon/PEEK pedicle screws in spinal tumour surgery have been described by Eicker et al, 2014 and Süss et al 2014, who also confirmed simplified and better dose-planning and radiotherapy with Carbon/PEEK implants.
Figure 1: Artefact reduction through Carbon/PEEK implant, right. (Left: titanium pedicle screw for comparison)
Figure 2: Dose planning for radiotherapy with Carbon/PEEK pedicle screws
References available on request from icotech
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