Correlation of nicotine dose and lumbar posterolateral fusion rate:imaging and biomechanical testing

Yang Bao-jia; Yang Kai-shun; Yao Ru-bin

doi:10.3969/j.issn.2095-4344.2016.48.016

Abstract：BACKGROUND:Smoking affects blood supply around the graft area, ultimately affecting spinal fusion. Few studies reported the effects of different doses of nicotine on spinal fusion. <br> OBJECTIVE:To evaluate nicotine effects on rabbit model of spinal fusion, and to clarify the correlation between the dose of nicotine and spinal fusion rate. <br> METHODS:Sixty healthy adult white rabbits aged 6-8 months were selected and randomly divided into four groups, with 15 rabbits in each group. Rabbits in the four groups received L5/6 posterior lumbar intertransverse fusion under intramuscular anesthesia. On day 1 after surgery, rabbits in the control group were subcutaneously injected with physiological saline 1 mL/kg, three times a day. Rabbits in other groups received different doses of nicotine solution:2, 4, 8 mg/kg through subcutaneous injection, three times a day. 12 weeks after surgery, effects of nicotine on the fusion rate of posterolateral lumbar interbody fusion surgery were determined by biomechanical testing, hand touch detection and imaging. <br> RESULTS AND CONCLUSION:(1) Hand touch detection and imaging:2 mg/kg nicotine did not have significant effect on spinal fusion. 4 and 8 mg/kg nicotine blocked spinal fusion and decreased fusion rate. (2) Biomechanical testing:Significant differences were detected between nicotine groups and control group (P<0.01). Significant differences were detectable among the three nicotine groups (P<0.01). No significant difference was determined between 4 mg/kg nicotine and 8 mg/kg nicotine groups (P>0.05). Al doses of nicotine affected cal us formation, reduced fusion rate;moreover, with the increased dose, the fusion rate obviously diminished. (3) These findings concluded that al doses of nicotine could decrease spinal fusion. Moreover, the effect of nicotine on spinal fusion was dose-dependent.