Hi, my name is Arati Patel, and I'm one of the first year neurosurgery residents at UCSF. And today I will be discussing the impact of smoking on outcomes following surgery for grade one lumbar spondylolisthesis. Smoking has been identified as an epidemiologic risk factor for low back pain and disc herniation. There are reports of a dose-dependent relationship between the number of cigarettes smoked and the frequency of low back pain. Accordingly, there has been a longstanding interest in the impact of smoking on fusion and spine surgery. And recently, there has been a shift towards examining how smoking influences patient satisfaction post-operatively, given that patient satisfaction and measures of quality of life are increasingly being used as proxies of success in spine surgery. A number of studies describe the adverse effects of smoking on post-operative satisfaction and quality of life in patients undergoing spine surgery. The Quality Outcomes Database, or QOD, is a prospective longitudinal registry designed to measure the quality and safety of spine surgery. As such, the aim of the present study was to investigate the impact of smoking on patient-reported outcomes and radiographic fusion through a retrospective analysis of the Quality Outcomes Database Registry. We queried the QOD database for data collected from July 2014 through June 2016 and examined the 608 patients undergoing surgery for Grade 1 lumbar spondylolisthesis. Multivariable linear regression was performed to assess for associations between smoking status and patient-reported outcomes, or PROs. Repeated measures ANOVA was performed to assess for differences in baseline and 24-month PRO scores. And binary logistic regression was performed to assess for an association between smoking and the ODI, MCID, and radiographic fusion at 24 months, respectively. There were 602 patients who underwent surgery for Grade 1 lumbar spondylolisthesis in the time period examined who had data available about their smoking status. This included 531 non-smokers and 71 smokers. A comparison of baseline characteristics in smokers and non-smokers is shown in the table on the right. As you can see, smokers were significantly more likely to have comorbid anxiety and less than 4 years of education compared to non-smokers. There was a higher incidence of comorbid depression in smokers that approached statistical significance. The two groups also had significant differences in baseline ODI. As you can see in the table on the right, the mean ODI score in smokers at baseline was 56.8 compared to non-smokers having a mean score of 45.5. In subsequent analyses, we controlled for these differences in baseline patient-reported outcomes along with the previously demonstrated differences in age, gender, BMI, education, depression, and anxiety. As demonstrated in the graph, both smokers, represented by the red line, and non-smokers, represented by the black line, had significant decreases in ODI postoperatively. However, non-smokers had a significantly greater degree of improvement in their ODI when compared to smokers even when controlling for covariates including depression and anxiety. Notably, there was no significant difference in the odds of achieving a minimum clinically important difference in ODI between the two groups. At the time of this study, the QOD database included 280 patients that underwent fusion procedures, among which 7.9% experienced non-union on radiographic examination. This included a 94% fusion rate amongst the smoking group and a 91.9% fusion rate in the non-smoking group. There were no significant differences in radiographic fusion between the smoking and non-smoking groups. So in conclusion, in the present study, we found that both smokers and non-smokers demonstrated a benefit from surgery for grade 1 lumbar spondylolisthesis. Non-smokers demonstrated a significantly greater degree of improvement in ODI from baseline compared to smokers even upon controlling for depression and anxiety. Smoking, importantly, did not impact the odds of achieving a minimum clinically important difference in ODI, which is a marker for treatment effectiveness, suggesting that smoking does not significantly impact the effectiveness of surgery for grade 1 lumbar spondylolisthesis. In the present study, in contrast to previous studies, smoking did not impact radiographic fusion. Smoking is currently being used to deselect patients from spine surgery, and the findings of this study call for a closer examination of our patient selection factors for lumbar spine surgery. I would like to thank my mentor, Dr. Mumineni, and the site PIs in the QOD group for the opportunity to conduct this study and their guidance throughout. And thank you for attending this presentation. I'd welcome any questions at the listed email address.

Arati Patel

neurosurgery resident

smoking

surgery outcomes

lumbar spondylolisthesis