Is it sufficient to treat adult lumbar spinal deformity using anterior lumbar interbody fusion with percutaneous pedicle screw fixation?

Case Report: Adult degenerative scoliosis in two patients treated with percutaneous spinal endoscopic-assisted lumbar interbody fusion and percutaneous pedicle screw fixation

Adult degenerative scoliosis (ADS) is a serious disease that often affects middle-aged and elderly people. ADS does not only cause sagittal and coronal deformity of the lumbar spine but also causes severe back and leg pain secondary to the compression of the neural structures. Open surgery remains the main method for correcting the occurring deformity and decompression of the neural structures; however, its benefit is limited in cases of large trauma. Minimally invasive spinal (MIS) surgery is an alternative method that has recently witnessed rapid development. It has the advantage of providing rapid recovery with less trauma as compared to conventional open surgery. We report two cases of ADS treated with percutaneous spinal endoscopic-assisted lumbar interbody fusion (EALIF) and percutaneous pedicle screw fixation. Both cases had moderate deformities of the lumbar spine (load-sharing classification 4-7 points) with severe back and leg pain, and they underwent successful MIS surgery. At 6 months of follow-up, the visual analog scale and Oswestry disability index scores of both patients improved and the deformity was corrected. For moderate ADS, percutaneous spinal EALIF and percutaneous pedicle screw fixation may achieve an effective correction of the deformity with direct decompression of neural structures.

The biomechanical effect on the adjacent L4/L5 segment of S1 superior facet arthroplasty: a finite element analysis for the male spine

Background

The superior facet arthroplasty is important for intervertebral foramen microscopy. To our knowledge, there is no study about the postoperative biomechanics of adjacent L4/L5 segments after different methods of S1 superior facet arthroplasty. To evaluate the effect of S1 superior facet arthroplasty on lumbar range of motion and disc stress of adjacent segment (L4/L5) under the intervertebral foraminoplasty.

Methods

Eight finite element models (FEMs) of lumbosacral vertebrae (L4/S) had been established and validated. The S1 superior facet arthroplasty was simulated with different methods. Then, the models were imported into Nastran software after optimization; 500 N preload was imposed on the L4 superior endplate, and 10 N⋅m was given to simulate flexion, extension, lateral flexion and rotation. The range of motion (ROM) and intervertebral disc stress of the L4-L5 spine were recorded.

Results

The ROM and disc stress of L4/L5 increased with the increasing of the proportions of S1 superior facet arthroplasty. Compared with the normal model, the ROM of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 2/5 from the apex to the base. The disc stress of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 1/5 from the apex to the base.

Conclusion

In this study, the ROM and disc stress of L4/L5 were affected by the unilateral S1 superior facet arthroplasty. It is suggested that the forming range from the ventral to the dorsal should be less than 3/5 of the S1 upper facet joint. It is not recommended to form from apex to base.

Level of evidence

Level IV