Prospective Clinical and Radiological Investigation of Fusion at the Lumbosacral Junction with an Anterior Standalone Device

Abstract

Introduction Fusion of lumbar motion segments has been shown to be effective for the treatment of low back pain (LBP) from degenerative disc disease (DDD) in a cohort of patients that has been shown to be unresponsive to conservative treatment. However, previous fusion techniques performed via posterior approaches have been associated with a variety of negative side effects. The goal of this investigation was to assess the clinical and radiological results in a cohort of patients treated with an anterior standalone device (Synfix LR, DePuy Synthes, West Chester, Pennsylvania, United States). Patients and Methods Patients included in this study are part of an ongoing prospective clinical trial with Synfix-LR (DePuy Synthes, West Chester, Pennsylvania, United States). The minimum follow-up (FU) for inclusion in this study was 12 months. Clinical outcome scores VAS, ODI, and satisfaction rates were acquired within the framework of an ongoing prospective clinical trial. Evaluation of radiological data included the pre- and postoperative segmental and global lumbar lordosis, neuroforaminal height and width. Interbody fusion was assessed from postoperative CT scans. Results The initial cohort consisted of 77 patients. A total of 71 patients were available for final FU, resembling a 92.2% FU rate after a mean FU of 35.1 months (range, 12.0–85.5 months). The overall results revealed a highly significant improvement from baseline VAS and ODI levels ( p < 0.0001). Overall, 77.5% ( n = 55/71) of all patients reported a “highly satisfactory” ( n = 37/71; 52.1%) or a “satisfactory” ( n = 18/71; 25.4%) outcome, 22.5% of patients were not satisfied. The overall complication rate was 12.7% ( n = 9/71). Radiographic analysis demonstrated a highly significant increase of segmental lordosis from 16.1 to 26.7 degrees ( p < 0.0001). Disc space height restoration ( p < 0.0001) was accompanied by a mild but statistically insignificant increase in foraminal width and height ( p > 0.05). A high rate of solid first ( n = 30/37; 81.1%) or second degree ( n = 6/37; 16.2%) interbody fusion was confirmed in 97.3% of all cases ( n = 36/37). Conclusion The data demonstrate satisfactory clinical results following anterior standalone fusion of the lumbosacral junction. Patient safety was proven with acceptable complication and reoperation rates, particularly when compared with posterior pedicle screw instrumented techniques. Radiological data demonstrated a significant reconstruction of lordosis at the lumbosacral junction while maintaining the overall global lumbar lordosis, which was accompanied by solid interbody fusion in 97.3% of all cases. The present data reveal that the currently described anterior standalone fusion is a viable treatment alternative in an attempt to avoid fusion related negative side-effects, which have previously been linked to a variety of posterior instrumented approaches and techniques.