Minimally Invasive Transforaminal Lumbar Interbody Fusion (MI-TLIF) vs. Minimally Invasive Lateral Lumbar Interbody Fusion (MI-LLIF): A Comparison of Immediate Post-Operative Outcomes for the Assessment of Decompression

Presented at SMISS Annual Forum 2018
By Sheeraz A. Qureshi MD, MBA
With Vaishnav MBBS, Catherine Gang MPH, Steven McAnany MD, Todd Albert MD,

Disclosures: Sheeraz Qureshi MD, MBA A; Cervical Spine Research Society. B; Zimmer-Biomet, Stryker Spiner, Globus Medical, Inc. D; Avaz Surgical. F; RTI, Zimmer-Biomet, Stryker Spine Vaishnav MBBS None, Catherine Gang MPH None, Steven McAnany MD None, Todd Albert MD B; Depuy, Biomet, Nuvasive, FacetLink. D; Vertech, In Vivo Therapeutics, Paradigm Spine, Biomerix, Breakaway Imaging, Crosstree, Invulty, Pioneer, Gentis, ASIP, PMIG. F; Depuy, Biomet, Nuvasive,


Surgical decompression to relieve pressure on neural structures can be performed by direct decompression (i.e. resection of impinging tissue), indirect decompression (i.e. distraction between vertebrae to increase the space), or a combination of the two.


To compare outcomes of surgical procedures that involve direct and indirect decompression (i.e. MI-TLIF) to procedures that involve only indirect decompression (i.e. MI-LLIF), to assess if the additional direct decompression results in better outcomes.


Clinical outcomes (length of stay, post-operative pain, in-hospital complications, need for additional direct decompression surgery), and patient-reported outcomes (PROs including ODI, VAS and SF-12) in patients undergoing MI-TLIF and MI-LLIF were compared using chi-square test for categorical and student’s t-test for continuous variables. Mixed ANOVA was used to assess if the change in PROs from pre-operatively to post-operatively was different between MI-TLIF and MI-LLIF.


Of the 72 patients,49 had MI-TLIF and 23 had MI-LLIF. There were no differences in age (58.88+12.31vs 61.77+8.84 years, p=0.255), sex (36.7%vs 54.2% males, p=0.157) or BMI (27.57+7.31vs 27.44+3.99 kg/m2, p=0.933). The number of levels operated was greater in the MI-LLIF group compared to the MI-TLIF group (1.43vs 1.12, p=0.047), with almost 90% of MI-TLIFs being 1-level procedures and none 3-level. In contrast, 65% of MI-LLIFs were 1-level, 26% 2-level and 8.7% 3-level procedures. The level(s) operated were different, with over 60% of MI-TLIFs at L4-L5 and 34.5% at L5-S1, compared to 51.6% of MI-LLIFs at L3-L4, 24.2% at each L2-L3 and L4-L5, and none at L5-S1. There was no difference in procedural time (105.31+29.56 minutes in MI-TLIF vs 126.00+85.63 in MI-LLIF, p=0.281), length of stay (45.39+32.99 hours in MI-TLIF vs 35.64+23.43 in MI-LLIF, p=0.216), post-operative pain (5.42+1.94 in MI-TLIF vs 5.65+2.37 in MI-LLIF, p=0.180), or in-hospital complications (10.2% in MI-TLIF vs 4.3% in MI-LLIF, p=0.384). Additionally, no patient in the MI-LLIF group required subsequent direct decompression surgery due to persistence of symptoms. ODI, VAS leg, SF-12 MHS, SF-12 PHS and PROMIS-PF did not differ between the groups preoperatively or at 2-weeks. VAS back pain was worse in the MI-LLIF group at both time-points (p=0.020). Additionally, the change in PROs did not differ between the groups (ODI: p=0.970, VAS back: p=0.982, VAS leg: p=0.667, SF-12 PHS: p=0.848, SF-12 MHS: p=0.495, PROMIS-PF: p=0.744).


There was no difference in outcomes between those who underwent MI-LLIF (indirect decompression), and those who underwent MI-TLIF (indirect and direct decompression). Thus, in an appropriately selected patient, indirect decompression can provide results that are comparable to direct compression. Underlying pathology, operative level and goals of the surgery should be kept in mind when selecting the procedure.