Comparison of Biportal Endoscopic Technique and Conventional Unilateral Laminectomy for Bilateral Decompression (ULBD) for Multi-Level Degenerative Lumbar Spinal Stenosis in Elderly People

Abstract

Objective: The object of this retrospective study was to compare the clinical, radiological, and spinal stability outcomes of biportal endoscopic Unilateral Laminectomy for Bilateral Decompression (BE-ULBD) and traditional Unilateral Laminectomy for Bilateral Decompression (ULBD) for multi-segmental lumbar spinal stenosis in elderly patients with osteoporosis.

Methods: We retrospectively identified 41 and 47 patients who underwent BE-ULBD and ULBD, respectively, who were diagnosed with multi-level lumbar stenosis and underwent double-segmental surgery in elderly patients. The clinical outcomes were evaluated using visual analogue scale (VAS) score for both back and leg pain, Oswestry Disability Index (ODI) score, and Zurich Claudication Questionnaire score during the two-year follow-up. The radiological changes of cross-sectional dural area (DCSA), facet joint preservation rate (PFJR) and cross-sectional fat infiltration ratio (FI) on the surgical side were evaluated by MRI before and after operation. At 2 years after operation, progressive spondylolisthesis and instability were evaluated in the X-ray of the lumbar spine.

Results: After 24 months of follow-up, the VAS scores for both back and leg pain, ODI, and Zurich Claudication Questionnaire in both groups were recovered compared to pre-operation. The postoperative VAS score for lower back pain in the BE-ULBD group was lower than in the ULBD group (1.00 ± 0.95 vs. 1.91 ± 1.07, p < 0.001), and the postoperative VAS score for lower limbs was similar (0.49 ± 0.51 vs. 0.46 ± 0.72, p < 0.001). The postoperative ODI score was lower than that of the ULBD group (9.05 ± 5.01 vs. 12.09 ± 6.18, p < 0.001), and the postoperative ZCQ score of the BE-ULBD group was lower than that of the ULBD group (10.59 ± 2.18 vs. 8.85 ± 1.59, p < 0.001; 7.00 ± 1.12 vs. 7.87 ± 1.63, p = 0.012; 8.95 ± 2.11 vs. 10.74 ± 2.47, p < 0.001). In terms of radiological evaluation, the DCSA of patients in both groups was effectively improved after surgery. Compared with the ULBD group, the BE-ULBD group had a tiny improvement in DCSA (195.04 ± 34.54 vs. 180.93 ± 31.07, p = 0.048) and a better FI (43.48 ± 10.24 vs. 53.93 ± 7.62, p < 0.001). The PFJR was higher (85.90 ± 4.03 vs. 81.26 ± 4.56, p < 0.001) in the BE-ULBD group. Two years after surgery, fewer patients in the BE-ULBD group had spondylolisthesis than in the ULBD group (1/41 vs. 7/46, p = 0.043). The results of complications were similar between the two groups.

Conclusion: BE-ULBD is a safe and effective technique for multilevel decompression surgery in elderly patients, which can better protect spinal stability and has better long-term follow-up than traditional surgery.

Keywords: BE‐ULBD; UBE surgery; clinical efficacy; imaging changes; multi‐level LSS.

FIGURE 1

Schematic of the “Over the top” technique. The red line on the left and the blue line on the right represent the surgical field of view for BE‐ULBD and ULBD surgeries, respectively. It can be seen that BE‐ULBD significantly enhances the surgical field of view and makes it easier to expose the contralateral nerve root.

FIGURE 2

Preoperative X‐ray pictures of incision positioning and postoperative matching combination of three incision positions. The incisions were made lateral to the medial border of the pedicle, and the working channels were positioned as parallel to the intervertebral disc plane as possible.

FIGURE 3

This figure shows the MRI DCSA changes before and 1 year after the BE‐ULBD surgery. The DCSA was changed from 0.534 to 1.536 cm².

FIGURE 4

This graph shows the changes of paraspinal muscle FI ratio before and after BE‐ULBD technique. Semi‐automatically delineated by 3D‐Slicer software, green represents muscle area and yellow represents fat area.

FIGURE 5

Box plot of paraspinal muscle FI ratio between the two groups before and after operation. OP represents the operative side and N represents the non‐operative side.