Objective: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) may be used to treat degenerative spinal pathologies while reducing risks associated with open procedures. As an increasing number of lumbar fusions are performed in the aging United States population, MIS-TLIF has been widely adopted into clinical practice in recent years. However, its complication rate and functional outcomes in elderly patients remain poorly characterized. The objective of this study was to assess complication rates and functional outcomes in elderly patients (≥ 65 years old) undergoing MIS-TLIF.
Methods: The PubMed, Embase, and Scopus databases were searched for relevant records in accordance with the PRISMA guidelines. Inclusion criteria were peer-reviewed original research; English language; full text available; use of MIS-TLIF; and an elderly cohort of at least 5 patients. Risk of bias was assessed using the ROBINS-I (Risk of Bias in Nonrandomized Studies-of Interventions) tool. Pooled complication rates were calculated for elderly patients, with subgroup analyses performed for single versus multiple-level fusions. Complication rates in elderly compared to nonelderly patients were also assessed. Postoperative changes in patient-reported outcomes, including Oswestry Disability Index (ODI) and visual analog scale (VAS) back pain (BP) and leg pain (LP) scores, were calculated.
Results: Twelve studies were included in the final analysis. Compared to nonelderly patients, MIS-TLIF in elderly patients resulted in significantly higher rates of major (OR 2.15, 95% CI 1.07-4.34) and minor (OR 2.20, 95% CI 1.22-3.95) complications. The pooled major complication rate in elderly patients was 0.05 (95% CI 0.03-0.08) and the pooled minor complication rate was 0.20 (95% CI 0.13-0.30). Single-level MIS-TLIF had lower major and minor complication rates than multilevel MIS-TLIF, although not reaching significance. At a minimum follow-up of 6 months, the postoperative change in ODI (-30.70, 95% CI -41.84 to -19.55), VAS-BP (-3.87, 95% CI -4.97 to -2.77), and VAS-LP (-5.11, 95% CI -6.69 to -3.53) in elderly patients all exceeded the respective minimum clinically important difference. The pooled rate of fusion was 0.86 (95% CI 0.80-0.90).
Conclusions: MIS-TLIF in elderly patients results in a high rate of fusion and significant improvement of patient-reported outcomes, but has significantly higher complication rates than in nonelderly patients. Limitations of this study include heterogeneity in the definition of elderly and limited reporting of risk factors among included studies. Further study of the impact of complications and the factors predisposing elderly patients to poor outcomes is needed.
Keywords: MIS-TLIF; complications; elderly; minimally invasive spine surgery; minimally invasive transforaminal lumbar interbody fusion; patient-reported outcomes.