Clinical outcomes of short-segment lumbar fusion in patients older than 85 years with a minimum 2-year follow-up

Although the number of elderly patients requiring lumbar fusion for lumbar degenerative disorders has increased over time, the postoperative outcomes of lumbar fusion in very elderly patients (> 85 years) remains unknown. This study aimed to evaluate the comprehensive outcomes of lumbar fusion in elderly patients older than 85 years with mid-term follow-up.The authors retrospectively researched patients older than 85 years who underwent single- or double-level posterior lumbar interbody fusion or transforaminal lumbar interbody fusion from 2012 to 2019. Twenty-nine patients who had at least 2 years of follow-up were included in this study. The average age was 86.4 years, and the average follow-up period was 42.2 months. Each patient was matched with 60- to 75-year-old controls. The Oswestry Disability Index (ODI) score; Roland-Morris Disability Questionnaire (RMDQ) score; Japanese Orthopaedic Association (JOA) score; JOA recovery rate; and low-back pain (LBP), leg pain, and leg numbness visual analog scale (VAS) scores were obtained. The spinopelvic parameters were measured using lateral standing radiographs of the whole spine.Although there were no significant differences in the ODI, RMDQ, JOA recovery rate, and leg pain and leg numbness VAS scores at 2 years postoperatively between the very elderly and control groups, the VAS LBP score was significantly lower in the very elderly group than in the control group. Preoperative and postoperative sagittal vertical axes were significantly higher and sacral slopes were significantly lower in the very elderly group than in the control group. The incidences of postoperative delirium and new lumbar vertebral fracture were significantly higher in the very elderly group (17.2%) than in the control group (4.6%).This study showed that lumbar fusion could be performed in patients older than 85 years with satisfactory postoperative outcomes at the 2-year follow-up. In contrast, progressive spinopelvic sagittal imbalance, the incidence of lumbar vertebral fracture up to the final follow-up, and postoperative delirium were greater in the very elderly group than in the control group.