Fatores preditivos de prognóstico em doentes submetidos a artrodese lombar transforaminal minimamente invasiva

Abstract

Background: Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has become an increasingly popular method of lumbar arthrodesis. While having similar long-term outcomes when compared to the open TLIF, it decreases the amount of intraoperative blood loss and iatrogenic muscle damage, the intensity of postoperative pain and the duration of hospital stays. However, uncertainty remains about which factors contribute to poor outcomes in these patients. Objective: The purpose of this study was to retrospectively analyze a cohort of patients submitted to MI-TLIF and try to identify factors that can be associated with a worse surgical outcome. Methods: Postoperative clinical outcome was assessed through a questionnaire that included personal data and validated outcome scores such as Odom's criteria. All the other variables were obtained through the patients' clinical records. Results: A total of 283 patients were included. The main variables associated with worse prognosis ("poor" class according to Odom's criteria) were: a period of sick leave longer than 3 months before the surgery (Chi-square, p=0.001; Phi=0.210), age under 50 years (Chi-square, p<0.001; Phi=0.29), lytic spondylolisthesis (Chi-square, p=0.030; Phi=0.14), L5-S1 fusion (Chi-square, p=0.023; Phi=0.15) and occurrence of complications (Chi-square, p=0.030; Phi=0.14). These five conditions were included in a binomial logistic regression analysis (Chi-Square, p<0.001), and three of them were independently associated to poor outcome: operative complications (OR: 3.26), age under 50 years (OR: 3.93) and sick leave longer than 3 months before surgery (OR: 2.75). Conclusions: Preoperative variables were identified as predictors of poor surgical outcome after MI-TLIF, suggesting that the result of lumbar fusion can be more limited in younger patients and those with sick leave for more than 3 months. Also, the existence of operative complications can decrease the likelihood of improvement.