Purpose of Study: To prospectively study the clinical and radiological outcomes following lumbar interbody fusion with an intersegmental device(SpineLink™, Biomet) in smokers versus non smokers.
Materials and Methods: 64 patients who underwent spine fusion with intrasegmental fixation were prospectively studied at Mayday University Hospital. 54 patients with suffient follow up were included. Patients were assessed pre and postoperatively clinically using validated scoring systems (VAS pain score, SF-36 v1, Oswestry Disability Index). Radiologically classified into fused, indeterminate or pseudoarthrosis.
Results: There were 54 patients in the analysis (34 patients in the smoker group and 20 patients in the non smoking group) with an average age of 52 years and an average follow-up of 28 months. 32 patients had multilevel procedures (25 two level, 5 three level, 2 four level). The treatment groups were comparable with respect to demographic, diagnostic (53% spondylolisthesis, 35% degenerative disc disease, 12% other) and surgical variables. No other significant medical problems affected patients in either group. Radiographically there were no pseudarthroses observed in either group. The SF-36 physical health score increased from 22.4 to 40.1 (+18.0) following surgery in smokers compared to an increase from 25.0 to 36.0 (+11.0) in non-smokers. The SF-36 mental health score increased from 36.4 to 45.0 (+8.6) in smokers compared to an increase of 30.8 to 42.7 (+2.9) in non-smokers. Complications included 2 nerve root injuries requiring hardware removal, and 3 deep infections which resolved with appropriate treatment.
Conclusions: There were no differences between smokers and non-smokers in radiographic fusion success or postoperative complications. As expected, smokers had lower SF-36 physical health and mental health scores pre-op, but unexpectedly, smokers had a greater degree of improvement in these scores postoperatively than non-smokers. Thus, from our experience, there is an incremental benefit to the use of intrasegmental fixation in smokers and warrants further investigation.
