Postoperative Footdrop Following Posterior Lumbar Spinal Fusion: Epidemiology, Risk Factors, and Associated Complications.

Methods: Retrospective cohort study. Objective: To assess the epidemiology, procedural risk factors, and associated complications of postoperative footdrop following posterior lumbar fusion.

Background: Footdrop is an uncommon complication following spine surgery that is associated with functional impairments. Understanding the epidemiology and risk factors of postoperative footdrop may allow for early implementation of preventive measures before and during surgery.

Methods: Adults who underwent posterior lumbar fusion were identified using PearlDiver. Eligible patients were stratified by the development of footdrop within 90 days of surgery. Epidemiological trends in footdrop were evaluated by age groups and year between 2010 and 2022. Patient demographics, comorbidities, procedural characteristics, hospital outcomes, and occurrence of intraoperative and postoperative complications were compared.

Results: In total, 2988 (0.6%) footdrop and 473,129 (99.4%) no footdrop patients were included, with a mean age of 60.9 years and 57.6% female sex. Postoperative footdrop rates increased from 0.4% to 0.8% between 2010 to 2022 and increased with age. Preoperatively, footdrop patients more frequently reported prior posterior spine surgery and medical comorbidities (all P<0.05). Intraoperatively, they had higher rates of 2 or more level fusion, osteotomy, dural tear, and nerve injury (all P<0.01). Postoperatively, they had higher rates of acute kidney injury, deep venous thrombosis, urinary tract infection, wound-related, hematoma, transfusion, and site-related complications, as well as higher rates of 90-day readmissions (all P<0.001).

Conclusions: Patients developing footdrop following lumbar spinal fusion were older, had more comorbidities, and frequently underwent complex multilevel procedures. They also had other postoperative complications, higher hospital readmissions, and increased health care expenditures. This data provides valuable insights into the risk factors and associated adverse outcomes for postoperative footdrop after lumbar spinal fusion.