Oral Posters: Values and Outcomes in Spine Surgery

Presented by: S. Virk - View Audio/Video Presentation (Members Only)

Author(s):

S. Virk(1), N. Jain(1), F. Phillips(2), H. Sandhu(3), A. Diwan(4), S. Khan(1)

(1) Ohio State University, Orthopaedics, Columbus, OH, United States
(2) Rush University Medical Center, Orthopaedics, Chicago, IL, United States
(3) Hospital for Special Surgery, Orthopaedics, New York, NY, United States
(4) University of New South Wales, Orthoapedics, Sydney, NSW, Australia

Abstract

Background: Lumbar discectomy has been shown to clinically beneficial in numerous studies for an appropriately selected cohort of patients. There is a subset of patients, however, that do require a revision discectomy procedure. No study to date has examined the long term rate of revision surgery on a national scale. Therefore, our aim was to perform a survival analysis for lumbar discectomy on a national scale using a life-table analysis.

Methods: The Medicare 5% national sample administrative database (SAF5) and a large national database from a commercial healthcare company (HORTHO) were used to catalog the number of patients undergoing a lumbar discectomy. We identified patients using relevant International Classification of Disease (ICD-9) codes and Current Procedural Terminology (CPT) codes. This included ICD-9 72210 (lumbar disc displacement) for disc herniation. We used CPT-63030 (laminotomy with decompression of nerve roots and/or excision of herniated intervertebral disc) and CPT-63056 (Transpedicular approach with decompression of nerve roots through removal of herniated intervertebral disc) to select patients that had a lumbar discectomy surgery. The timing of a potential revision surgery was identified when and if CPT-63042 (Laminotomy, re-exploration single interspace, lumbar) was used. Revision surgery rates were also calculated for patients above and below the age of 60. We used the Rothman exact method in order to calculate the 95% confidence interval for each cumulative rate of survival at each time point. We compared the rate of revision over 7 years using a Z-ratio for the significance of the difference between two ratios and a chi-square test to compare revision rates across geographic areas.

Results: There were a total of 10,923 patients that underwent a lumbar discectomy surgery for an intervertebral disc displacement and had at least 5 year follow up within the HORTHO and SAF5 databases. There were 7,094 patients that had a lumbar discectomy surgery in the HORTHO database with a revision surgical rate of 6.0% (425 patients). There were 3,829 patients in the SAF5 database and the revision rate was 5.8% (221 patients). Survival analysis showed survival rates above 93% for all cohorts up to 7 years after the surgery. We did not identify a statistically significant difference in survival rate between patients over and under 60 years of age. The highest rate of repeat discectomy occurred in the first year after the index procedure. There was no significant difference in revision discectomy rates across geographic regions.

Conclusions: Our study shows high rates of cumulative survival at 7 years after an index lumbar discectomy procedure. Revision rates for over 10,000 patients undergoing a lumbar discectomy was 5.99% and 5.77% at 7 years follow up in the HORTHO and SAF5 databases respectively.