Percutaneous Carbon-PEEK instrumentation for spine tumors: a prospective observational study

Background: Minimally invasive spine surgery (MISS) has been progressively accepted as a useful approach for spine tumors. Recently released carbon-PEEK implants have been already reported as effective in open surgeries for spine tumors. This study aimed to evaluate the feasibility, surgical, clinical and radiological outcomes of a new percutaneous carbon-PEEK instrumentations for spine tumors. Methods: This is a prospective case-control observational study. Demographical, clinical, surgical, and radiological data were collected from May 2018 to August 2019. Visual analogue scale for back pain (VAS), the Oswestry Disability Index (ODI) questionnaire, EORTC QLQ-C30 questionnaire for quality of life, and ASIA impairment scale (AIS) were collected before surgery and at 6 weeks and follow-up visits. Data were compared with the control group, a retrospective series of 23 metastatic patients that underwent titanium pedicle screw fixation. Results: Twenty-one patients met inclusion criteria. Mean age was 59.2 years (range, 35-78) and mean follow-up was 14.2 months (7-22). Thoracic spine was involved in 14 (66.7%) cases, lumbar spine in 7 (33.3%). The mean length of surgery was 75 (42-185) minutes, mean blood loss was 90ml (50-215) and every patient was mobilized within 24 hours after surgery. The VAS (8.3±1.1 to 2.9±1.0, p<0.05) and ODI (54.6±11.7 to 25.1±5.4, p<0.05) scores significantly improved over follow-up. AIS improved in 7 (33.3%) patients and remained unchanged in 14 (66.7%). The EORTC QLQ-C30 global health/QoL, functional and symptomatic scales significantly improved postoperatively and at the last follow-up. Only two minor complications (9.5%) were recorded. No statistically significant difference was observed between the two groups related to clinical, radiological outcomes, complications rate and implant failure. Conclusions: Percutaneous Carbon/PEEK implants could be considered as alternative to standard titanium implants in oncological patients, according to their lower rate of MRI artifacts, facilitating radiological follow-up and adjuvant radiotherapy. Further clinical trials and biomechanical evaluations are needed to confirm our preliminary results.