Exploring the differences in radiologic and clinical outcomes of transforaminal lumbar interbody fusion with single- and bi-planar expandable cages: a systematic review and meta-analysis.

Transforaminal lumbar interbody fusion (TLIF) is a universal surgical technique used to achieve lumbar fusion. Traditionally static cages have been used to restore the disc space after discectomy. However, newer technological advancements have brought up uniplanar expandable cages (UECs) and more recently bi-planar expandable cages (BECs), the latter with the hope of reducing the events of intra- or postoperative subsidence compared to UECs. However, since BECs are relatively new, there has been no comparison to UECs. In this PRISMA-compliant systematic review, we sought to identify all Medline and Embase reports that used UECs and/or BECs for TLIF or posterior lumbar interbody fusion. Primary outcomes included subsidence and fusion rates. Secondary outcomes included VAS back pain score, VAS leg pain score, ODI, and other complications. A meta-analysis of proportions was the main method used to evaluate the extracted data. Bias was assessed using the ROBINS-I tool. A total of 15 studies were pooled in the analysis, 3 of which described BECs. There were no studies directly comparing the UECs to BECs. A statistically significant difference in fusion rates was found between UECs and BECs (p = 0.04). Due to lack of direct comparative literature, definitive conclusions cannot be made about differences between UECs and BECs. The analysis showed a statistically higher fusion rate for BECs versus UECs, but this should be interpreted cautiously. No other statistically significant differences were found. As more direct comparative studies emerge, future meta-analyses may clarify potential differences between these cage types.

Expandable versus static cages in unilateral biportal endoscopy lumbar interbody fusion (ULIF) for treating degenerative lumbar spondylolisthesis (DLS): comparison of clinical and radiological results.

BACKGROUND: In recent years, early rehabilitation after spinal fusion and the recovery of physiological curvature have attracted much attention. Therefore, expandable cages have entered the field of vision of scientists. The goal of the current study was to compare the clinical and radiological results of unilateral portal endoscopic lumbar interbody fusion (ULIF) in the treatment of degenerative lumbar spondylolisthesis (DLS) with expandable versus static cages. METHODS: We retrospectively analysed patients who received ULIF treatment for DLS from May 2019 to February 2021. Patients were categorized by cage type (static vs. expandable), and the main study was the preop and postop clinical and radiological index changes of the patients. RESULTS: Eighty-four patients were included (38 in the static cages group; 46 in the expandable cages group). There was no difference in the preop results between the two groups. The VAS scores for low back and leg pain and ODI scores in the expandable cages group 7 d postop were significantly superior to those in the static cages group (P < 0.05), and the segmental angle and PDH in the expandable cages group postop were significantly higher than those in the static cages group (P < 0.05). The fusions at 6 m postop in the expandable cages group were superior to those in the Static Cages group (P < 0.05). CONCLUSIONS: The results of this study showed that compared with the stable cage group, the expandable cage group had unique advantages in restoring the physiological curvature of the lumbar spine, increasing the fusion rate, and relieving pain in the early postoperative period. ULIF can be used to treat single-segment, mild lumbar spondylolisthesis patients using expandable cages instead of static cages.

Expandable Versus Static Cages in Minimally Invasive Lumbar Interbody Fusion: A Systematic Review and Meta-Analysis.

BACKGROUND: Expandable cages for interbody fusion allow for in situ expansion optimizing fit while mitigating endplate damage. Studies comparing outcomes after using expandable or static cages have been conflicting. METHODS: This was a meta-analysis A systematic search was performed in accordance with the Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) guidelines identifying studies reporting outcomes among patients who underwent minimally invasive lumbar interbody fusion (MIS-LIF). RESULTS: Fourteen articles with 1129 patients met inclusion criteria. Compared with MIS-LIFs performed with static cages, those with expandable cages had a significantly lower incidence of graft subsidence (expandable: incidence 0.03, I2 22.50%; static: incidence 0.27, I2 51.03%, P interaction <0.001), length of hospital stay (expandable: mean difference [MD] 3.55 days, I2 97%; static: MD 7.1 days, I2 97%, P interaction <0.01), and a greater increase in disc height (expandable: MD -4.41 mm, I2 99.56%; static: MD -0.79 mm, I2 99.17%, P interaction = 0.02). There was no statistically significant difference among Oswestry Disability Index (expandable: MD -22.75, I2 98.17%; static: MD -17.11, I2 95.26%, P interaction = 0.15), fusion rate (expandable: incidence 0.94, I2 0%; static incidence 0.92, I2 0%, P interaction = 0.44), overall change in lumbar lordosis (expandable: MD 3.48 degrees, I2 59.29%; static: MD 3.67 degrees, I2 0.00%, P interaction 0.88), blood loss (expandable: MD 228.9 mL, I2 100%; static: MD 261.1 mL, I2 94%, P interaction = 0.69) and operative time (expandable: MD 184 minutes, I2 95.32%; static: MD 150.4 minutes, I2 91%, P interaction = 0.56). CONCLUSIONS: Expandable interbody cages in MIS-LIF were associated with a decrease in subsidence rate, operative time and greater in increase in disc height.