Opioid Requirements Following Unilateral and Bilateral Minimally Invasive Transforaminal Lumbar Interbody Fusion

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

Disclosures: Abbas Naqvi BS 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, Islam Elboghdady None, Eric Sundberg MD None, Hamid Hassanzadeh MD None, Anton Jorgensen MD None, Khaled Aboushaala MD None,

Introduction:
Emerging literature suggests comparable clinical outcomes between unilateral and bilateral instrumentation for MIS TLIF procedures. The impact of these two techniques on peri-operative narcotic consumption has not been previously described.

Aims/Objectives:
To identify the differences in peri-operative narcotic utilization between unilateral and bilateral instrumentation techniques for a minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF).

Methods:
A cohort of patients who underwent a primary MIS TLIF procedure for degenerative spinal pathology between 2007-2013 was retrospectively analyzed. Patients were stratified based upon the instrumentation technique (unilateral vs. bilateral) and assessed with regards to demographics, comorbidity burden, smoking status, intraoperative parameters, rates of in-hospital complications, and length of hospitalization. Cumulative and daily (postoperative day (POD)) in-hospital narcotic requirements (expressed in oral morphine equivalent (OME) doses) were also analyzed. 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 118 single-level MIS TLIF procedures identified, 74 (62.7%) were performed with unilateral and 110 (37.3%) with bilateral instrumentation. The unilateral cohort demonstrated a higher comorbidity burden (CCI: 3.18±2.19 vs 2.41±1.52; p<0.05) and lower percentage of smokers (9.1% vs. 25.7%; p<0.05) than the bilateral cohort. Unilateral instrumentation was associated with shorter mean operative times (106.9±25.9 vs 146.8±47.7 min; p<0.05) and lower estimated blood loss (56.9±15.9 vs. 78.9±60.0 ml; p<0.05). Both cohorts experienced comparable length of stay (60.7±22.1 vs. 58.4±16.9 hrs; p<0.57) and complication rates. Patients with unilateral instrumentation more often received patient controlled anesthesia (PCA: 94.6% 79.5%, p<0.05) and demonstrated a delay in discharge with higher OME doses on POD 2. Cumulative opioid utilization did not significantly differ with regards to instrumentation.

Conclusions:
Patients who underwent a bilateral MIS TLIF demonstrated a slightly greater cumulative OME dose compared to unilateral MIS TLIFs that was not statistically significant. Hospitalization and peri-operative complication rates were similar for both groups. Further studies are warranted to better characterize the association between lower cumulative narcotic consumption, unilateral instrumentation, and patient controlled anesthesia (PCA).