Background context:

Published rates for disk reherniation following primary discectomy are around 6%, but the ultimate re-operation outcomes in patients after receiving revision discectomy are not well understood. Additionally, any disparity in the outcomes of SRD vs SLF following primary/revision discectomy remains poorly studied.

Purpose:

To determine the 8-year subsequent revision discectomy (SRD)/subsequent lumbar fusion (SLF) rates and time until SRD/SLF after primary/revision discectomy respectively.

Study design:

Retrospective cohort study.

Patient sample:

Patients undergoing primary or revision discectomy, with records in the PearlDiver Patient Records Database from the years 2010-2019.

Outcome measures:

Subsequent surgery type and time to subsequent surgery.

Methods:

Patients were grouped into primary or revision discectomy cohorts based off of the nature of “index” procedure (primary or revision discectomy) using ICD9/10 and CPT procedure codes from 2010-19 insurance data sets in the PearlDiver Patient Records Database. Preoperative demographic data was collected. Outcome measures such as subsequent surgery type (fusion or discectomy) and time to subsequent surgery were collected prospectively in PearlDiver Mariner database. Statistical analysis was performed using BellWeather statistical software. A Kaplan-Meier survival analysis of time to SLF/SRD was performed on each cohort, and log-rank test was used to compare the rates of SLF/SRD between cohorts.

Results:

A total of 20,147 patients were identified (17,849 primary discectomy, 2,298 revision discectomy). The 8-year rates of SRD (6.1% in revision cohort, 4.8% in primary cohort, P<0.01) and SLF (10.4% in revision cohort, 6.2% in primary cohort, P<0.01) were higher after revision vs primary discectomy. Time to SLF was shorter after revision vs primary discectomy (709 vs 886 days, P<0.01). After both primary and revision discectomy, the 8-year rate of SLF (10.4% in revision cohort, 6.2% in primary cohort, P<0.01) is greater than SRD (6.1% in revision cohort, 4.8% in primary cohort, P<0.01).

Conclusion:

Compared to primary discectomy, revision discectomy has higher rates of SLF (10.4% vs. 6.2%), and faster time to SLF (2.4 vs 1.9 years) at 8-year follow up.