Does interbody cage lordosis impact actual segmental lordosis achieved in minimally invasive lumbar spine fusion?

Abstract

OBJECTIVEIn an effort to prevent loss of segmental lordosis (SL) with minimally invasive interbody fusions, manufacturers have increased the amount of lordosis that is built into interbody cages. However, the relationship between cage lordotic angle and actual SL achieved intraoperatively remains unclear. The purpose of this study was to determine if the lordotic angle manufactured into an interbody cage impacts the change in SL during minimally invasive surgery (MIS) for lumbar interbody fusion (LIF) done for degenerative pathology.METHODSThe authors performed a retrospective review of a single-surgeon database of adult patients who underwent primary LIF between April 2017 and December 2018. Procedures were performed for 1–2-level lumbar degenerative disease using contemporary MIS techniques, including transforaminal LIF (TLIF), lateral LIF (LLIF), and anterior LIF (ALIF). Surgical levels were classified on lateral radiographs based on the cage lordotic angle (6°–8°, 10°–12°, and 15°–20°) and the position of the cage in the disc space (anterior vs posterior). Change in SL was the primary outcome of interest. Subgroup analyses of the cage lordotic angle within each surgical approach were also conducted.RESULTSA total of 116 surgical levels in 98 patients were included. Surgical approaches included TLIF (56.1%), LLIF (32.7%), and ALIF (11.2%). There were no differences in SL gained by cage lordotic angle (2.7° SL gain with 6°–8° cages, 1.6° with 10°–12° cages, and 3.4° with 15°–20° cages, p = 0.581). Subgroup analysis of LLIF showed increased SL with 15° cages only (p = 0.002). The change in SL was highest after ALIF (average increase 9.8° in SL vs 1.8° in TLIF vs 1.8° in LLIF, p < 0.001). Anterior position of the cage in the disc space was also associated with a significantly greater gain in SL (4.2° vs −0.3°, p = 0.001), and was the only factor independently correlated with SL gain (p = 0.016).CONCLUSIONSCompared with cage lordotic angle, cage position and approach play larger roles in the generation of SL in 1–2-level MIS for lumbar degenerative disease.

What Affects Segmental Lordosis of the Surgical Site after Minimally Invasive Transforaminal Lumbar Interbody Fusion?

“…This is in line with Carlson, et al 31 who reported that an anterior position of the cage resulted in larger postoperative SL. Lovecchio, et al 19 also reported that SL increased more following ALIF than after TLIF or LLIF, and they thus concluded that cage position was the only factor influencing SL change after MIS-TLIF. We also found that the Yc axis of the cage was associated with SL, with an anterior cage position correlating with an increase in SL after MIS-TLIF.…”

“…Many studies have reported a relationship between cage characteristics and lordosis. 12 13 14 15 16 17 18 19 20 21 22 However, how cage position affects postoperative lordosis after MIS-TLIF has only been studied indirectly by comparing dichotomized groups of anterior or posterior cage positioning. 14 19 In this study, we sought to identify factors that may affect segmental lordosis (SL) after MIS-TLIF by comparing patients whose SL increased with those whose decrease.…”

Meta-Analysis of the Clinical Effect of MIS-TLF Surgery in the Treatment of Minimally Invasive Surgery of the Orthopaedic Spine

“…However, none of these changes were statistically significant. At the rear of the neck, the lumbar spine is fused [ 7 ].…”

Minimally invasive transforaminal lumbar interbody fusion — A narrative review on the present status

“…The anatomical factors like unilateral facetectomy and lack of anterior release in MIS TLIF limited the segmental sagittal lordosis. 36 Champagne et al 37 retrospectively compared the sagittal balance correction in 148 patients with open TLIF, MIS TLIF and OLIF and found that pelvic incidence and pelvic tilt remained the same in all and only OLIF could significantly increase the segmental lordosis. The lumbar lordosis was significantly improved only with OLIF and not with MIS TLIF.…”