Influence of Alendronate and Endplate Degeneration to Single Level Posterior Lumbar Spinal Interbody Fusion

Abstract

ObjectiveUsing alendronate after spinal fusion is a controversial issue due to the inhibition of osteoclast mediated bone resorption. In addition, there are an increasing number of reports that the endplate degeneration influences the lumbar spinal fusion. The object of this retrospective controlled study was to evaluate how the endplate degeneration and the bisphosphonate medication influence the spinal fusion through radiographic evaluation.MethodsIn this study, 44 patients who underwent single-level posterior lumbar interbody fusion (PLIF) using cage were examined from April 2007 to March 2009. All patients had been diagnosed as osteoporosis and would be recommended for alendronate medication. Endplate degeneration is categorized by the Modic changes. The solid fusion is defined if there was bridging bone between the vertebral bodies, either within or external to the cage on the plain X-ray and if there is less than 5° of angular difference in dynamic X-ray.ResultsIn alendronate group, fusion was achieved in 66.7% compared to 73.9% in control group (no medication). Alendronate did not influence the fusion rate of PLIF. However, there was the statistical difference of fusion rate between the endplate degeneration group and the group without endplate degeneration. A total of 52.4% of fusion rate was seen in the endplate degeneration group compared to 91.3% in the group without endplate degeneration. The endplate degeneration suppresses the fusion process of PLIF.ConclusionAlendronate does not influence the fusion process in osteoporotic patients. The endplate degeneration decreases the fusion rate.

A Systematic Review of Treatment Strategies for Degenerative Lumbar Spine Fusion Surgery in Patients With Osteoporosis

“…Kim et al also studied the effect of alendronate on 44 patients undergoing single-level lumbar interbody fusion and instrumentation in 2014 and found different results. 17 They found a nonstatistically significant difference in the fusion rates as assessed by plain radiographs. The patients in the alendronate group had a fusion rate of 66.7% and the control group had 73.9%, with an overall higher rate of patients with end plate degeneration in the alendronate group.…”

Bisphosphonate's and Intermittent Parathyroid Hormone's Effect on Human Spinal Fusion: A Systematic Review of the Literature

“…Dosing was given starting two months before surgery and continued for ten months after surgery [ 11 ], in 3-month cycles [ 15 ], beginning two months before surgery and continued for eight months after surgery [ 12 ], and the final study was given in short duration (less than six months) or long duration (greater than six months) groups [ 13 ]. Demographic information is listed in Table 2 [ 8 9 10 11 12 13 14 15 16 ].…”

“…At one year postoperatively, fusion was observed in 95% (18/19) of the alendronate group and 65% (11/17) of the control group ( p =0.025). There were also higher rates of cage subsidence in the control group (5 patients) versus the alendronate group (1 patient), however this was not statistically significant ( Table 3 ) [ 8 9 10 11 12 13 14 15 16 ].…”

The effects of bisphosphonates on osteoporotic patients after lumbar fusion: a meta-analysis

“… 11 , 14 , 16 In a retrospective controlled study, Kim et al found that endplate degeneration decreases the fusion rate and that alendronate does not influence the fusion process. 12 …”