Topping-off surgery vs posterior lumbar interbody fusion for degenerative lumbar disease: a comparative study of clinical efficacy and adjacent segment degeneration

Studies have shown that adjacent segment degeneration (ASD) is a common complication after posterior lumbar interbody fusion (PLIF), even a second surgery is required for some patients. It remains unclear whether the non-fusion surgery can relieve ASD. Therefore, this study aims to investigate the clinical outcomes of Topping-off surgery (fusion combined with Coflex) and PLIF for degenerative lumbar disease (DLD) and the efficacy on preventing ASD.A retrospective analysis was performed on the clinical data of 99 patients with DLD from January 2011 to December 2014, who were performed by Topping-off surgery (L4-5 PLIF + L3-4 Coflex, n = 45) or PLIF (L3-5 PLIF, n = 54). All patients included in the analysis had a minimum of 3 years of follow-up. Clinical data were used to assess the clinical efficacy, and radiographic parameters were measured for evaluation of the incidence of ASD.The mean ages of Topping-off group and PLIF group were 53.5 and 65.7 years old, respectively (P < 0.05). The surgical time, intraoperative blood loss, Oswestry disability index (ODI), and visual analog scale (VAS) were significantly different between the two groups (P < 0.05). Intervertebral mobility (L2-L3) of the Topping-off group was not changed significantly at 3 years after surgery than before (P > 0.05), while that of PLIF group was increased considerably (P < 0.05). As to intergroup comparison, intervertebral mobility (L2-L3) of Topping-off group was superior to those of the PLIF group (P < 0.05). Surprisingly, there was no significant difference in the general adjacent segment mobility (GASM) at L2-4 of the Topping-off group and intervertebral mobility (L2-L3) of PLIF group at 3 years after surgery (P > 0.05). Lumbar MRI at three post-operative years indicated that the modified Pfirrman grading of disc (L2-L3) in the Topping-off group was much better than that of the PLIF group (P < 0.05).This study showed that Topping-off surgery had the benefits of less invasiveness, less bleeding, and comparable clinical efficacy as PLIF for DLD. The segment with Coflex insertion undertook part of the mobility and stress in the proximal lumbar spine, which is conducive to alleviating ASD.