Risk Factors Associated With Revision Microdiscectomy or Subsequent Spinal Fusion Within Two Years of Index Lumbar...

Area of Science:

• Neurosurgery
• Spine Surgery
• Health Services Research

Background:

• Lumbar microdiscectomy is a common procedure for disc herniation.
• Reherniation rates range from 3% to 18%, necessitating further investigation into revision surgery predictors.
• While revision microdiscectomy rates are known, fusion rates and risk factors post-index microdiscectomy require more study.

Purpose of the Study:

• To determine the rates of revision microdiscectomy and fusion within two years of an initial lumbar microdiscectomy.
• To identify patient characteristics and comorbidities that predict the need for subsequent revision surgeries.

Main Methods:

• Retrospective review of insurance claims and electronic medical records from a large US health organization (January 2016 - December 2019).
• Analysis of 8,158 patients undergoing index lumbar microdiscectomy.
• Statistical analysis included chi-square tests, Fisher exact tests, time-to-event modeling, and Cox proportional hazards regression to identify predictors.

Main Results:

• Within two years, 5.5% of patients had revision microdiscectomy and 6.6% had fusion.
• Patients aged 40-59, females, and those with Charlson Comorbidity Index (CCI) comorbidities were more likely to undergo fusion, but not revision microdiscectomy.
• Each additional CCI comorbidity significantly increased the likelihood of fusion (HR 1.35 for CCI=1 to HR 2.47 for CCI ≥ 3).

Conclusions:

• Two-year rates for revision microdiscectomy and fusion after lumbar microdiscectomy are 5.5% and 6.6%, respectively.
• Patient age (40-59), female sex, and presence of comorbidities predict fusion, not revision microdiscectomy.
• Comorbidities significantly elevate the risk of requiring fusion surgery post-lumbar microdiscectomy.