Postoperative Narcotic Consumption following a Minimally Invasive Lumbar Decompression Surgery in Medicare Beneficiaries

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

Disclosures: Islam Elboghdady None 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, Eric Sundberg MD None, Hamid Hassanzadeh MD None, Anton Jorgensen MD None, Khaled Aboushaala MD None, Junyoung Ahn None,

Introduction:
Medicare beneficiaries are comprised of older and more comorbid patients that may be at a greater risk of narcotic related adverse events in the immediate postoperative period. As such, these patients are likely to benefit from less invasive techniques to minimize postoperative narcotic consumption.

Aims/Objectives:
To characterize the differences in postoperative narcotic consumption between Medicare (MC) patients and non-MC patients following a minimally invasive (MIS) lumbar decompression (LD) procedure.

Methods:
335 patients who underwent a primary one- or two-level MIS LD procedure (laminectomy or diskectomy) for degenerative spinal pathology between 2006-2013 were retrospectively analyzed. Patients were stratified based upon the primary payor status (MC vs non-MC) and assessed with regards to patient demographics, comorbidity burden, smoking status, length of hospitalization, peri-operative outcomes, and daily (postoperative day (POD)) in-hospital oral morphine equivalent (OME) dosing. Statistical analysis was performed with a chi-squared test for categorical variables and Student-Test for continuous variables. OME means were compared utilizing non-parametric analysis to adjust for skewedness. A p-value of <0.05 denoted statistical significance.

Results:
Of the 335 LD procedures, 43 (12.8%) were performed on MC beneficiaries. MC patients were older (68.2±12.1 vs 42.8±11.9 years old; p<0.05), and demonstrated a greater comorbidity burden (CCI: 4.47±1.79 vs 1.45±1.61; p<0.05) than non-MC patients. The MC cohort more often underwent a two-level LD (55.8% vs 17.8%, p<0.05), and incurred a longer operative time (56.9±16.4 vs 41.9±19.2 min, p<0.05), higher rates of peri-operative complications (durotomy and urinary retention), and longer hospitalizations (35.9±29.7 vs 14.6±15.2 hours, p<0.05) compared to the non-MC cohort. MC patients demonstrated lower cumulative narcotic consumption in all discharge days, however these differences were not statistically significant (POD 0: 15.6±12.9 vs 18.4±11.6mg, p=0.26; POD 1: 61.6±47.0 vs 98.2±213.7 mg, p=0.20; POD 2: 41.5±30.5 vs 99.9±105.6 mg, p=0.14; POD 3+: 116.1±98.8 vs 121.6±97.2 mg, p=0.69).

Conclusions:
Despite more extensive surgery and worsened peri-operative outcomes, MC patients did not demonstrate significant differences in cumulative narcotic consumption between MC and non-MC patients following a MIS LD procedure. Furthermore, MC patients demonstrated a slightly lower cumulative OME dose despite a longer hospitalization. These findings suggest that the greater rate of urinary retention incurred by MC patients may be associated with greater age and comorbidity rather than excessive narcotic dosing.