Carbon fibre/polyether ether ketone (CF/PEEK) implants in orthopaedic oncology

A 77-year-old male patient presents with severe non-radiating back pain at the thoracolumbar junction without accompanying sensorimotor deficits. Radiological assessment with conventional x-ray and magnetic resonance imaging (MRI) shows an osteolytic lesion with pathologic fracture of the T12 vertebra, unilaterally diminished vertebral body height and consecutive de novo scoliosis of 10° (Fig. 1). The lesion also features a left paravertebral and epidural soft-tissue involvement without compromise of neurological structures. CT-guided transpedicular biopsy revealed multiple myeloma (Durie-Salmon stage I, R-ISS stage I). With a Spine Instability Neoplastic Score (SINS) of 13 points (junctional, non-mechanical pain, lytic lesion, deformity (scoliosis), < 50% collapse, unilateral involvement of the posterolateral elements), the lesion was judged unstable and surgical stabilization was planned prior to subsequent radiation therapy [10]. The patient underwent unnavigated dorsal instrumentation and fusion from T11 to L1 using CF/PEEK pedicle screws and rods (icotec AG BlackArmor® pedicle system 5.5 mm) with apposition of iliac crest autograft and demineralized bone matrix (Fig. 2). Postoperatively, the patient had to wear a supportive customized thoracolumbar orthosis for 8 weeks. After rehabilitation and uneventful wound healing, a consolidating and analgesic radiation therapy with CT-based planning (total 30 Gray) was administered in a volumetric modulated arc therapy (VMAT) technique. A cytotoxic therapy with bortezomib, cyclophosphamide and dexamethasone has been initiated for systemic disease progression and achieved full remission after four cycles. No further surgical intervention was undertaken during the follow-up period (25 months). From a surgical point of view, the patient reported a very satisfactory outcome and stated an Oswestry Disability Index of 20%.

A 77-year-old male patient recognizes a mass in his dorsal upper arm. He seeks medical attendance when the lesion starts to be painful during the night a few weeks later. The patient also reports an unintended weight loss of 5 kg and recent night sweats. Radiological imaging shows an osteolytic lesion of the distal humerus with permeative growth and radial cortical penetration (Mirels’ score 8 points [11]) (Fig. 3). Histopathologic evaluation after CT-guided core needle biopsy yielded an extensively necrotic metastasis from a prostatic carcinoma (pT1c cN0 M1b, Gleason Score 4 + 4 = 8, prostate-specific antigen 499 ng/ml). A systemic therapy with denosumab and goserelin was initiated. Due to significant cortical weakening (30%) with a non-displaced pathologic fracture, surgical stabilization was opted for prior to cytotoxic therapy with docetaxel and radiotherapy. Intralesional curettage was followed by open bridge plating using a CF/PEEK 4.5-mm locking compression plate (CarboFix Orthopedics Ltd. “Piccolo” Narrow Diaphyseal Plate) (Fig. 4). The intraoperative handling of the chosen implant was straightforward and without unexpected incidents. Postoperatively, no weight-bearing and only careful passive mobilization was permitted for 6 weeks. Additionally, an arm sling was worn until complete wound healing had been attained. During routine follow-up, the patient presented without pain at his upper arm. The palliative radiotherapy (total 30 Gray) was administered subsequently. Likewise, the remaining follow-up (6 months) was uneventful. With regard to his arm, the patient reported very favourable and pain-free course allowing for any desired sports activity and stating a QuickDASH score of 22.5 points as well as a subjective limb value of 90%.

A 17-year-old male patient experiences intermittent pain and swelling at his left anterior tibia. Four months after onset of symptoms, the patient seeks medical advice. With a radiographically lytic and lobulated lesion of the tibial diaphysis featuring cortical erosion and focal penetration (Fig. 5), referral to our institution was prompted. CT-guided needle biopsy revealed the rare finding of an intraosseous schwannoma. Even though benign, tumour resection was aspired in this symptomatic patient. To allow for better radiological surveillance during follow-up of this rare lesion, a CF/PEEK rather than a metallic implant was chosen. Due to the expansive growth (Mirels’ score 9 points [11]), prophylactic plate stabilization was needed. After complete curettage of the intraosseous lesion, the cavity was filled with cancellous bone allograft. Surgery was then completed by open bridge plating with use of a CF/PEEK 4.5-mm locking compression plate (CarboFix Orthopedics Ltd. “Piccolo” Narrow Diaphyseal Plate) (Fig. 6). Again, the applicability of the chosen CF/PEEK implant was uncomplicated. Besides a prolonged wound secretion without need for special measures, the postoperative course was uneventful. After completing 48 h of relaxed bed rest, the patient was mobilized on crutches with partial weight-bearing (15 kg). During routine follow-up, the patient presented pain free with unremarkable clinical findings. Radiographically, progressive ossification could be detected throughout the follow-up (8 months). At the last follow-up, the patient-reported outcome using the SGOT (Swiss Society of Orthopaedics and Traumatology) Minimal Dataset revealed a pain-free well-being with full work capacity, a moderate limitation in sports activity (5/10 points) and a subjective limb value of 90%.