Surgical Survivorship of Lumbar Diskectomy in Medicare Beneficiaries

Presented at SMISS Annual Forum 2014
By Kern Singh MD
With Sreeharsha Nandyala BA, Alejandro Marquez-Lara MD, Islam Elboghdady , Eric Sundberg MD, Hamid Hassanzadeh MD, Anton Jorgensen MD, Khaled Aboushaala MD, Junyoung Ahn ,

Disclosures: Kern Singh MD A; CSRS Resident Grant. B; DePuy, Zimmer, Stryker, CSRS, ISASS, AAOS, SRS, Vertebral Column - ISASS. D; Avaz Surgical, LLC, Vital 5, LLC. F; Zimmer, Stryker, Pioneer, Lippincott Williams & Wilkins, Th Sreeharsha Nandyala BA None, Alejandro Marquez-Lara MD None, Islam Elboghdady None, Eric Sundberg MD None, Hamid Hassanzadeh MD None, Anton Jorgensen MD None, Khaled Aboushaala MD None, Junyoung Ahn None,

Lumbar decompression surgery has demonstrated to be safe and effective for appropriately selected patients. However, the longevity of minimally invasive lumbar diskectomy procedures, as a function of Medicare status, has not been previously described.

To compare the one-year survival between Medicare (MC) and non-Medicare patients undergoing a minimally invasive (MIS) 1 or 2 level lumbar diskectomy.

251 patients who underwent a primary 1 or 2 level lumbar diskectomy for degenerative spinal pathology between 2007-2013 were retrospectively reviewed. Only those with a minimum follow-up time of 12 months were included for analysis. Patients were stratified based upon the primary payor status (MC and non-MC) and assessed with regards to patient demographics, Charlson comorbidity index (CCI), and body mass index (BMI). The incidence and prevalence of revision surgeries at 12-months were calculated by the Kaplan-Meier method. Survivorship distributions were compared with the Log-Rank test and a p-value of <0.05 was utilized to denote statistical significance.

Of the 251 lumbar diskectomies identified, 192 demonstrated a minimum follow up of one-year. Medicare patients were older (64.4±13.5 vs 39.5±10.9, p<0.05), and demonstrated a greater comorbidity burden (CCI: 4.00±1.78 vs 1.08±1.30, p=0.50) than non-MC patients. One year after index lumbar decompression, 6.2% (1/16) and 14.2% (25/176) of MC and non-MC patients, respectively, required a revision procedure. There were no significant differences in the type of revision surgery (arthrodesis vs decompression) between the two cohorts (p=0.27). Kaplan-Meier analysis predicted a survival rate of 93.8% (n=15/16) at 1 year in MC patients and 85.8% (n=151/176) in non-MC patients. Survivorship distributions between the two cohorts did not significantly differ. (Log-Rank: Chi-square 0.83, p=0.36).

Roughly one out of seven patients (13.5%) who underwent an MIS lumbar diskectomy in our series required a revision procedure within the first 12-months. Despite the older and more comorbid patient population of Medicare beneficiaries, the one-year survival was comparable to non-Medicare patients. Although further long-term data is warranted, these findings suggest that MIS techniques are effective alternatives for lumbar decompression procedures.