Indirect Decompression of the Neural Elements Utilizing Direct Lateral Interbody Fusion Procedure.

INTRODUCTION

Patients suffering from degenerative scoliosis curves often present with radicular symptoms mainly on the concave side of their curves. Standard treatment includes posterior decompressions, followed by fusions. These procedures carry large morbidity rates. We have observed resolution of radicular and stenotic symptoms with Direct Lateral Interbody Fusions (DLIF).

AIM: In this study we radiographically assess indirect decompression effect of DLIF procedure.

METHODS

We conducted a case series of four patients with 2-stage procedures. All patients presented with back pain and leg symptoms. Stage one included the insertion of the DLIF polyetheretherketone cages and rh-BMP2. This was followed by a second stage posterior fixation utilizing percutaneous pedicle screws and rods. Plain radiographs were utilized to determine the concave and convex sides of the scoliosis. Pre- and post-DLIF measurements were made from axial and sagittal MRIs. Measurements included central, subarticular, and foraminal areas. Statistical significance was estimated via paired sample t-test.

RESULTS

All patients had complete resolution of leg symptoms with remarkable improvement in all areas measured. When both concave and convex sides of the curve are considered, an increase of 49% in the central canal, 82% in the subarticular area, and 71% in the foraminal area was measured. When only the concave levels were measured, there was a 90% increase (0.22 cm2 vs. 0.41 cm2) in the subarticular area and 77% (0.46 cm2 vs. 0.81 cm2) increase in the foraminal area (p < .001).

CONCLUSION

The DLIF procedure provides an indirect decompression of the neural elements along with its role in spinal fusion. This negates the need for posterior decompression surgery in degenerative scoliosis associated with spinal stenosis, which might lead to less blood loss and surgical time in these complex surgeries.