ABSTRACT
STUDY DESIGN: Clinical and basic study. OBJECTIVES: This study aimed to investigate whether transforaminal lumbar interbody fusion (TLIF) using 2 banana-shaped cages leads to good clinical outcomes. METHODS: First, we conducted a clinical study to compare outcomes among patients who underwent TLIF using different types or numbers of cages. Propensity matched patients in each group were reviewed. Thirty-four patients who underwent surgery with 2 bullet-shaped cages (group A), 34 with a banana-shaped cage (group B), and 34 with 2 banana-shaped cages (group C) were compared. Twelve months after the surgery, bony fusion and cage subsidence were evaluated. RESULTS: The mean amount of cage subsidence was 14.9% in group A, 19.9% in group B, and 11.8% in group C. Subsidence in group B was significantly greater than that in group C (P < .01). Radiological bony fusion was not achieved in 2 cases in group B. Second, we performed a finite element model (FEM) analysis to determine the biomechanical stress of the vertebral endplate by comparing the single-banana cage construct with a double banana-shaped cage construct. FEM analysis showed that the maximum stress of the endplate in the single-cage model was 1.72-times greater than the maximum stress in the double-cage model. Furthermore, the maximal stress in the single-cage model was significantly higher than in the double-cage model during lumbar extension and side bending. CONCLUSION: This study showed that TLIF with double banana-shaped cages led to good clinical outcomes with less cage subsidence, probably because of decreased mechanical stress on the vertebral endplate.
ABSTRACT
PURPOSE: This study aimed to compare the differences in functional recovery between patients undergoing plate and nail fixation in the very early period after surgery. METHOD: This study was designed as a controlled clinical trial that included 18 patients who were surgically treated with either dynamic hip screw as plate fixation or proximal femoral nail as nail fixation for stable intertrochanteric fractures. In particular, all patients selected for the study reported walking completely independently without the use of walking aids prior to sustaining their initial fracture. In all, 8 patients (mean age, 73.8 years; range, 65-89 years) were treated with plate fixation (group plate) and 10 patients (mean age, 79.7 years; range, 70-90 years) were treated with nail fixation (group nail). Functional evaluations were assessed every week after surgery using the Japanese Orthopaedic Association (JOA) hip functional scores and active range of motion (ROM) of the hip joint. RESULTS: The recovery of activities of daily living (ADLs) according to JOA hip functional scores at week 4 after surgery was significantly better in group nail than in group plate (P = .03), whereas active ROM of hip flexion improved significantly in group plate than in group nail at weeks 3 and 4 after surgery (P = .04 and P = .02, respectively). CONCLUSIONS: The results suggested that nail fixation may provide a more rapid recovery of ADLs than that of plate fixation in the very early period after surgery. However, plate fixation may provide better ROM of hip flexion than that of nail fixation.
