General Session: Spinal Innovation
Presented by: P. Louie - View Audio/Video Presentation (Members Only)
G. Shifflett(1), J. Kaikaus(1), M. Goczalk(1), B. Basques(1), P. Louie(1), F. Phillips(1)
(1) Rush University Medical Center, Chicago, IL, United States
Introduction: Traditionally anterior cervical plate (ACP) fixation with structural allograft has been used for reconstruction after anterior decompression of the cervical spine. More recently, stand-alone (SA) cages with integrated screw fixation have been popularized for cervical reconstruction; however, there is little comparative data between these two procedures.
Materials and Methods: Consecutive patients who underwent either SA or ACP procedures for one level degenerative pathology performed by one surgeon at a single institution between 2011 and 2013 were evaluated. Plain lateral radiographs of the cervical spine were performed pre-operatively, immediately post-operatively, and at final follow-up. The following radiographic parameters were assessed: pre-operative disc height, T1 slope, focal lordosis, overall cervical lordosis, C2-C7 sagittal vertebral angle (cSVA), and interbody cage subsidence. Symptomatic pseudarthrosis and reoperation rates were recorded.
Results: Sixty-two patients were included in the study (33 ACP and 29 SA). Average follow-up was 16.8 months. There were no significant differences in baseline demographic variables including age, sex, obesity, smoking, or level of operation (Table 1). Both constructs were equally effective at restoring local and segmental lordosis (p>0.05) (Table 2). The SA construct was as effective as the allograft-ACP construct in terms of restoration of disc height, focal or global lordosis, and cSVA. There was no statistical difference (p>0.05) between the average immediate post-operative height of the surgical segment (35.2+/-3.7mm) when compared to the height of the surgical segment at final follow-up (34.1+/-3.7mm) for all patients. Subsidence (defined as >3mm loss of overall surgical segment height from immediate post-operative to final follow-up) occurred in 12.1% of ACP cases and 13.7% of SA constructs (p>0.05). There were no significant differences in symptomatic pseudarthrosis rates requiring reoperation between the two groups at final follow-up. Independent risk factors for reoperation were male sex (p=0.049) and smoking (p=0.017).
Conclusion: These results indicate that SA anterior cervical discectomy and fusion results in equivalent radiographic alignment parameters when compared to ACP constructs with no difference in pseudarthrosis or reoperation rates. SA constructs generally are faster to apply and are often entirely intra-discal which may reduce swallowing difficulties associated with prominent ACPs . In addition SA constructs are less likely to impinge on adjacent level discs compared to ACPs. This information is useful for surgical decision-making and informing future studies that seek to further identify differences between these two procedures.