Carbon fiber–reinforced PEEK instrumentation in the spinal oncology population: a retrospective series demonstrating technique, feasibility, and clinical outcomes

Abstract

OBJECTIVE The authors aimed to demonstrate the feasibility and advantages of carbon fiber–reinforced PEEK (CFRP) composite implants in patients with both primary and secondary osseous spinal tumors. METHODS Twenty-eight spinal tumor patients who underwent fixation with CFRP hardware were retrospectively identified in a Spine Tumor Quality Database at a single institution. Demographic, procedural, and follow-up data were retrospectively collected. RESULTS The study population included 14 females and 14 males with a mean age of 60 years (range 30–86 years). Five patients had primary bone tumors, and the remaining patients had metastatic tumors. Breast cancer was the most common metastatic tumor. The most common presenting symptom was axial spine pain (25 patients, 89%), and the most common Spine Instability Neoplastic Score was 7 (range 6–14). Two patients in this series had anterior cervical procedures. The remaining patients underwent posterior thoracolumbar fixation. The average fusion length included 4.6 vertebral segments (range 3–8). The mean clinical follow-up time with surgical or oncology teams was 6.5 months (range 1–23 months), and the mean interval for last follow-up imaging (CT or MRI) was 6.5 months (range 1–22 months). Eighteen patients received postoperative radiation at the authors’ institution (16 with photon therapy, 2 with proton therapy). Eleven of the patients (39%) in this series died. At the last clinical follow-up, 26 patients (93%) had stable or improved neurological function compared with their preoperative status. At the last imaging follow-up, local disease control was observed in 25 patients (89%). Two patients required reoperation in the immediate postoperative period, one for surgical site infection and the other for compressive epidural hematoma. One patient was noted to have lucencies around the most cephalad screws 3 months after surgery. No hardware fracture or malfunction occurred intraoperatively. No patients required delayed surgery for hardware loosening, fracture, or other failure. Early tumor recurrence was detected in 3 patients. Early detection was attributed to the imaging characteristics of the CFRP hardware. CONCLUSIONS CFRP spinal implants appear to be safe and comparable to conventional titanium implants in terms of functionality. The imaging characteristics of CFRP hardware facilitate radiation planning and assessment of surveillance imaging. CFRP hardware may enhance safety and efficacy, particularly with particle therapy dosimetry. Larger patient populations with longer-term follow-up are needed to confirm the various valuable aspects of CFRP spinal implants.

Fifty‐year history of the evolution of spinal metastatic disease management

“…Materials transitioned from stainless steel to titanium, which improved postoperative MR‐imaging and the fidelity of radiation delivery. New anterior reconstruction techniques were introduced, including polymethylmethacrylate (PMMA), titanium and PEEK carbon fiber cages, and anterior plating systems 23–25 …”

“…New anterior reconstruction techniques were introduced, including polymethylmethacrylate (PMMA), titanium and PEEK carbon fiber cages, and anterior plating systems. [23][24][25] During this period, the goal of operations for spine metastases was not only spinal cord decompression for neurological function, but also gross total resection of the tumor followed by cEBRT to achieve durable tumor control. [4][5][6]8 Early in this period of surgical evolution, transarterial embolization for hypervascular tumors (i.e., renal cell carcinoma) was developed, which facilitated safer intralesional, gross total tumor resection.…”

Navigation accuracy and assessability of carbon fiber-reinforced PEEK instrumentation with multimodal intraoperative imaging in spinal oncology

“…The general feasibility of using radiolucent CFRP pedicle screws in spinal oncology has previously been demonstrated 8,12,16 but little is known about the performance of state-of-the art intraoperative 3D imaging for spinal navigation and implant assessment of CFRP pedicle screws. This is important, however, because spinal navigation and robotics is gaining increasing attention and screw trajectories of CFRP implants within the pedicle are more difficult to identify.…”

“…Since the majority of all misplacements were noted within the range of 2-4 mm (category C), such highly sensitive breach detection and categorization might have unmasked category B (or C) CFRP screws that would otherwise have been graded as category A (or B) using titanium implants. Second, implantation of CFRP pedicle screws requires knowledge of certain technical nuances for successful implantation, such as meticulous selection of the screw entry point in order to ensure precise alignment, given the inability to bend the pre-shaped carbon fiber rods that we used 16 . Third, in oncologic spinal disease we typically aim to implant the largest possible screw diameter just below the pedicle isthmus diameter to ensure maximum pullout resistance and limit the risk of a pedicle breach.…”

“…Navigation accuracy for CFRP pedicle screws was considerably lower than expected from reports on titanium implants and CT may be best for reliable assessment of CFRP materials.For patients with spinal oncological disease, posterior pedicle screw fixation with or without circumferential decompression, en-bloc spondylectomy, or anterior cage reconstruction represents an accepted strategy to address tumor burden, cord compression, instability and pain [1][2][3][4][5][6][7] . Against this background, technology in the field of spine surgery has evolved towards the development of new implant materials and computer-assisted image guidance: Carbon fiber reinforced PEEK (CFRP) has been reported to have biomechanical screw properties comparable to standard titanium implants 8 with distinct advantages of reduced imaging artifacts 9 , less perturbation effects 10 and the potential to significantly improve planning, safety and quality of adjuvant radiotherapy and follow-up [10][11][12][13][14][15][16] . Real-time spinal navigation with intraoperative 3D imaging has improved pedicle screw accuracy [17][18][19][20][21][22] , reduced radiation exposure for the OR team 23 , and holds promise to improve outcomes 24 .…”