Transforaminal Lumbar Interbody Fusion Using LOOP® PEEK Cage Implants: Safety, Feasibility, Radiographic and Clinical Outcome

Objective: A variety of newly designed grafts for  transforaminal lumbar interbody fusion (TLIF) have been introduced for clinical application. Biomechanical properties of the LOOP ® PEEK cage (Medtronic GmbH, Meerbusch, Germany) have been shown in cadaver laboratory investigations, but not in clinical studies so far. In this study we analyze the safety, clinical and radiological outcome of the LOOP ® PEEK cage implant in a clinical setting. Methods : Forty one consecutive patients undergoing fluoroscopic-guided posterior pedicle screw fixation combined with TLIF using the LOOP ® PEEK cage for degenerative spine disease s between January 2010 and December 2011 were included. Time intervals for follow-up, clinical and radiological outcome data collection were at 1, 3 and 12 months. Visual analog pain scales (VAS), neurological exam, patient-reported SF-12 ® , CT- scans and plain x-rays of the lumbar spine were used as clinical and radiologic outcome measures. Following data were recorded for safety evaluation: procedure duration, intraoperative blood loss, number of levels fused, intraoperative complications, hospitalization time, and postoperative complications. Results:  A total of 49 cages were implanted during 41 procedures with an average procedure time of 225.25 minutes. Four patients (9.8%) experienced a dural tear, While new sensory and motor deficits were seen in 2 (4.9%) and 1 (2.4%) patients respectively. complications were not associated with  implant insertion. Significantly reduced pain scores (p<0.05, paired t-test) were reported by 29 patients (70%) at 1, 3 and 12 months. SF-12 ® results showed PCS and MCS scores below the healthy population average, one year post-op. Cage dislocation was observed in 2 (4.9%) patients, one required late revision. Implant fracture did not occur. Inchoate fusion of the vertebra was seen in 39 patients (95.1%) at one year. Conclusion:  TLIF procedure combined with lumbar fusion using LOOP ® -PEEK cage, provides a safe and feasible intraoperative alternative as well as good clinical and radiologic outcome, without increasing the overall complication rate of TLIF procedures.