111 - Minimally Invasive Lateral Interbody Fusion (MI-LIF) at L4-5 and the P...

#111 Minimally Invasive Lateral Interbody Fusion (MI-LIF) at L4-5 and the Protective Effect of Prophylactic Dexamethasone

Lumbar Therapies and Outcomes

Poster Presented by: J.A. Lehme


W.B. Rodgers (1)
J.A. Lehmen (1)
J.A. Rodgers (1)
E.J. Gerber (1)

(1) Spine Midwest, Inc., Research, Jefferson City, MO, USA


Introduction: It has been reported that MI-LIF procedures performed at the L4-5 level have a higher incidence of postoperative motor deficits compared to other lumbar segments, and must occasionally be aborted to due anatomic constraints.

Methods: In our single-site consecutive series of 1236 MI-LIF patients, 725 (59%) included the L4-5 level. Clinical and radiographic data were prospectively collected and reviewed to assess MI-LIF procedure at the L4-5 level.

Results: Age averaged 62.5 years (24-89 years). 69.8% had one or more comorbidities. 34.3% had prior lumbar surgery. All procedures were successfully completed. Hospital stay averaged 1.4 days. Average VAS pain scores improved from 8.5 at pre-op to 2.8 at 12 months and 2.7 at 24 months follow-up. Lenke fusion scores of 1-2 were present in 91.8% at 6 months, and 96.9% at 24 months.

Neural complications included 5 (0.4% of all cases, 0.7% of L4-5 cases) transient lower leg weaknesses (4 quads, 1 anterior tibialis; all but one resolved within 3 months). After the fourth postoperative motor deficit, we began to administer dexamethasone (10mgIV prior to skin incision) prophylactically in all MI-LIF patients in whom the L4-5 level was to be approached. Since the use of dexamethasone, only one neural deficit developed, a statistically significant difference (p=0.0245).

Conclusions: The incidence of postoperative motor deficits following MI-LIF at L4-5 is low. The prophylactic administration of dexamethasone results in a statistically significant reduction in motor deficits.