Comparison of 1-Year Clinical and Radiographic Outcomes Between 2 Expandable Cage Designs in Navigation-Assisted...

Area of Science:

• Spine surgery
• Orthopedic surgery
• Biomedical engineering

Background:

• Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) often faces challenges in restoring adequate lordotic alignment.
• Expandable cage design, specifically height and lordotic angle, is crucial for successful outcomes.
• This study compares two MIS-TLIF expandable cage designs: one enhancing disc height only (Group H) and another enhancing both height and lordosis (Group HL).

Purpose of the Study:

• To compare the efficacy of two expandable cage designs in MIS-TLIF for restoring spinal alignment and clinical outcomes.
• To evaluate the impact of cage design on segmental lordosis, disc height, subsidence, and fusion rates.
• To assess the clinical relevance of surgeon experience in mitigating cage subsidence.

Main Methods:

• A retrospective review of 75 patients undergoing navigation-assisted MIS-TLIF with expandable cages.
• Patients were divided into two groups: Group H (35 cases, height-only expansion) and Group HL (40 cases, height and lordosis expansion).
• Clinical outcomes (pain scores, Oswestry Disability Index) and radiographic parameters (disc height, lordosis, subsidence, fusion) were analyzed.

Main Results:

• Both groups demonstrated significant clinical improvement, with no intergroup differences.
• Group HL showed significantly greater improvements in segmental lordosis and disc angle at 1-year follow-up compared to Group H.
• Overall fusion rate was 92%, with an initial subsidence rate of 32% decreasing to 20% with experience.

Conclusions:

• Expandable cages designed for both height and lordosis expansion in MIS-TLIF offer superior segmental lordosis improvement.
• Both cage designs achieve high fusion rates and comparable clinical outcomes.
• Surgeon experience is vital for minimizing cage subsidence and optimizing clinical results.