Transforaminal lumbar interbody fusion with an expandable interbody device: Two-year clinical and radiographic outcomes

Background: The use of interbody cages as an adjunct to lumbar spinal fusion remains an important technique to enhance segmental stability, promote solid arthrodesis, maintain neuroforaminal decompression, and preserve/improve segmental lordosis. Appropriate segmental lumbar lordosis and sagittal balance is well-known to be critical for long-term patient outcomes. This study sought to evaluate the radiographic and clinical results of TLIF in patients using an articulating, expandable cage. Primary endpoint was clinical and radiographic outcomes, including complications, at 12 and 24 months. Methods: A total of 37 patients underwent open single-level or 2-level TLIF by a single surgeon using an expandable cage with concomitant bilateral pedicle screws and posterolateral arthrodesis. Clinical outcomes included ODI and VAS for back and legs. Radiographic outcomes included pelvic incidence and tilt, lumbar and segmental lordoses, and disc height at the operative level(s). All outcomes were collected at baseline, 2-weeks, 6-weeks, 3-months, 6-months, 12-months, and 24-months postop. Results: A total of 28 patients were available for analysis. Nine patients failed to follow-up at 24 months. Mean ODI scores showed significant improvement, from pre-to-postoperative at 24 months (55%; p<.0001). VAS for back and legs was significantly lower at 24 months on average by 72 and 79%, respectively (p<.0001 for both). Both segmental and lumbar lordoses significantly improved by 5.3 degrees and 4.2 degrees (p<.0001 and p=.049), respectively. Average disc height improved by 49% or 6.1 mm (p<.001). No device-related complications nor instances of measured subsidence. One patient had a superficial infection, and another had an intraoperatively repaired incidental durotomy. Conclusions: The use of an expandable cage contributed to improvement in both segmental and lumbar lordosis with no reported complications at 24-month follow-up. All clinical measures significantly improved as well. The expandable cage design represents an effective and safe option to increase cage size and allow significant segmental lordosis correction.