Background:

Expandable transforaminal lumbar interbody fusion (TLIF) cages capable of multidirectional in situ expansion have gained popularity as they increase axial surface area for fusion and may enhance lordotic correction through a traditional MIS surgical corridor.

Objective:

To evaluate and compare the radiographic and clinical outcomes between a novel expandable vs. static MIS TLIF cage for the treatment of degenerative disc disease.

Study design:

A single center retrospective review of 120 consecutive adult patients undergoing 1 or 2-level MIS TLIF with an expandable (n=60) or static cage was performed between 2015-2019. Preoperative and 1-year postoperative radiographic and clinical outcomes were assessed by upright flexion/extension radiographs and serial confidential surveys.

Results:

120 patients (mean age 63.5 years, 60.0 % female) undergoing 1 and 2-level MIS TLIF met inclusion criteria. A statistically significant reduction of spondylolisthesis, restoration of foraminal, anterior and posterior disc height was achieved in both cohorts, but greater in the ECC (all p<0.05). Comparable rates of fusion, 93% and 91% were observed in the ECC and SCC. A significant reduction in NRS back and ODI scores were observed in both cohorts but more pronounced in the ECC (5.9±2.4 to 2.2±1.9 and 37.3±16.2 to 17.1±15.2) vs. SCC (6.2±2.8 to 3.2±2.5 and 41.8±16.1 to 24.3±17.5) (p<0.05). One instance of cage migration requiring reoperation occurred in the ECC.

Conclusions:

Taken together, these radiographic and clinical findings suggest an expandable cage placed through an MIS corridor represents a safe, equitable and efficacious alternative to a static TLIF in adults with degenerative lumbar pathology.