A Critical Retrospective Analysis of Patient Generated Outcomes in a Large Series of Patients Undergoing MI-TLIF

Introduction: Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has become an important surgical intervention to treat a variety of spinal disorders affecting the lumbar spine including spondylolisthesis, spinal stenosis and degenerative disc disease (DDD). This analysis is one of the largest MI-TLIF retrospective series conducted with prospective patient reported outcomes (PROs).

Methods: A retrospective series of 606 consecutive patients (286(47%)males:320(53%) female, mean age 64.4+/-12.2 years, BMI = 29.9+/-6 kg/m2) undergoing MI-TLIF was conducted from November 2011 to August 2022. Demographic and surgical variables included age, BMI, gender, length of stay (LoS), co-morbidities, complications, re-operation rate, pre and postoperative disc height, and long-term PROs. Summary analyses were completed to evaluate operative parameters and long-term outcomes. All patients underwent interbody device insertion and rotation to restore disc and foraminal height, use of drilled local morselized autograph bone to fill the disc space, and bilateral percutaneous pedicle screws.

Results: Co-morbidities include hypertension (142(23.4%)), diabetes (49(8.1%)), hyperlipidemia (58(9.6%)), history of cardiac disease (153(25.2%)), and history of malignancy (79(13.0%)). An average of 14.7±4.3cc of graft material was implanted at each fused segment and mean LoS was 2.68±2.9 days. One patient required neuromodulation placement due to chronic pain, 17 patients developed post-operative wound infections; 3 patients required re-operation: one due to postoperative foot drop, one due bone graft extrusion, and one due to broken hardware. VAS back and ODI scores improved from 7.1 and 42.3 preoperatively to 2.3 and 25.6 at one year, respectively (P < 0.0001 for both). Disc height averaged 9.43 pre-operatively which increased to 11 mm at last follow-up. Plain radiographic dynamic independent analysis averaging 35.7 months follow-up showed greater than 95% fusion rate.

Conclusion : This study represents one of the largest MI-TLIF series analyzed over a ten year period showing significantly improved patient outcomes, high fusion rates, and low complication rate.