Pedicle screw augmented posterior interbody versus posterolateral arthrodesis in single-level low-grade isthmic lumbar spondylolisthcsis : radiological and clinical outcome

الملخص EN

Background data : For many years, poster lateral arthrodesis has been the standard procedure for lumbar spondylolisthesis even prior to the era of pedicle screw fixation.

This procedure preserve an intact disc, avoid manipulating the nerve root and dura hence reduce the epidural scarring and neural morbidity.

Still some cases need discectomy, root decompression in those cases poster lateral arthrodesis loses its advantages.

Study design : This is a prospective descriptive study comparing two homogenous groups of patients with single-level low grade isthmic spondylolisthesis treated with posterior interbody and poster lateral fusion augmented with pedicle screw fixation.

Methodology : Fifty patients were included in this study, half of them were treated with interbody fusion (group-1), and the other half was treated with poster lateral fusion (group-II).

In both groups the lamina was chipped and used as graft.

All patients were followed clinically and radio logically for at least 6 months.

Visual Analogue Scale and Prolo's Rating Scale were used to evaluate pain and the clinical outcome.

The preoperative, immediate postoperative, and last follow-up values of the percentage of slippage, the disc height, sacral inclination, and segmental lordosis are measured.

Fusion was sound when bone trabeculae were observed to cross the fusion bed and segment was stable at dynamic study.

Results : Fusion rate was 92% and 64% in group-I and II respectively.

Stability of the segment was preserved in 96% and in 80% in group-I and II respectively.

Slippage percentage and disc height were improved by surgery.

With follow-up, both parameters had tendency to return toward the preoperative values.

Maintenance of the corrected deformity intended by slippage and disc height was significantly greater in group-I.

Sacral inclination and segmental lordosis did not change by surgery in both groups.

According to Prolo's economic and functional scale, surgery achieved good outcome in 72% and 80% in group-I respectively, and 68% and 64% in group-II respectively.

The average changes were calculated and compared and changes were not statistically different.

Conclusion : The technique successfully achieved solid fusion with good neurological recovery, and good economic and functional results.

Mechanical reliability (maintained alignment) was superior in group-I, and there was no inter-group difference regarding the clinical outcome.

Anterior column restoration facilitates listless reduction, restores lordosis, and produces a more anatomic reconstruction of the listhclic segment.