BackgroundGiven the lack of guidelines regarding the operative management of elderly patients needing lumbar spine fusion for degenerative disease, it is often difficult to balance between invasiveness respecting the fragile spine and geriatric comorbidities.AimTo compare reoperation rates and clinical outcome in patients above 70 years of age undergoing Transforaminal Lumbar Interbody Fusion (TLIF) with titanium rods or posterior stabilization with Polyetheretherketone (PEEK) rods for the treatment of one-level lumbar spine degenerative disease.MethodsRetrospective review of baseline characteristics, reoperation rates as well as the clinical and radiological outcomes of patients, older than 70 years, undergoing posterolateral fusion with PEEK rods (n= 76, PEEK group) or TLIF with titanium rods (n= 67, TLIF group) for a single-level lumbar degenerative disease from 2014 to 2020. Additional subanalysis on the patients above 80 years of age was performed.ResultsOur results showed similar reoperation rates and outcomes in the TLIF and PEEK groups. However, intraoperative blood loss, administration of tranexamic acid, and operation time were significantly higher in the TLIF group. In patients older than 80 years, reoperation rates at first follow-up were significantly higher in the TLIF group, too.ConclusionAccording to our results, posterior stabilization with PEEK rods is less invasive and was associated with significantly lower blood loss, administration of blood products and shorter operation time. Moreover, in patients above 80 years of age reoperations rates were lower with PEEK rods, as well. Nevertheless, the benefits of PEEK rods for foraminal stenosis still have to be investigated.