Unilateral biportal endoscopy vs. open decompression for lumbar epidural lipomatosis-cohort study using a prospective registry

Abstract

Objective: This study aimed to compare the outcomes of unilateral biportal endoscopy, unilateral laminectomy bilateral decompression (UBE-ULBD), and open lumbar decompression (OLD) in patients with lumbar epidural lipomatosis (LEL).

Methods: This prospective observational study was conducted from March 2019 to May 2022 and encompassed 33 patients with LEL who underwent lumbar decompression. The study included 15 cases of UBE-ULBD decompression and 18 cases of open decompression, which were followed up for 1 year. The baseline characteristics, initial clinical manifestations, and surgical details [including estimated blood loss (EBL) and preoperative complications] of all patients were recorded. Radiographic evaluation included the cross-sectional area (CSA) of the thecal sac and paraspinal muscles on MRI. Clinical results were analyzed using the Short Form-36 Score (SF-36), the Numeric Pain Rating Scale (NRS) for lumbar and leg pain, creatine kinase, the Roland and Morris Disability Questionnaire (RMDQ), and the Oswestry Disability Index (ODI).

Results: The dural sac CSA increased considerably at the 1-year postoperative follow-up in both groups (p < 0.001). The operative duration in the OLD group (48.2 ± 7.2 min) was shorter than that in the UBE-ULBD group (67.7 ± 6.3 min, p < 0.001). The OLD group (97.2 ± 19.8 mL) was associated with more EBL than the UBE-ULBD group (40.6 ± 13.6 mL, p < 0.001). The duration of hospitalization in the OLD group (5.4 ± 1.3 days) was significantly longer compared with the UBE-ULBD group (3.5 ± 1.2 days, p < 0.01). The SF-36, NRS, RMDQ, and ODI scores improved in both groups postoperatively (p < 0.001). Serum creatine kinase values in the UBE-ULBD group (101.7 ± 15.5) were significantly lower than those in the OLD group (330.8 ± 28.1 U/L) 1 day after surgery (p < 0.001). The degree of paraspinal muscle atrophy in the UBE-ULBD group (4.81 ± 1.94) was significantly lower than that in the OLD group (12.15 ± 6.99) at 1 year (p < 0.001).

Conclusion: UBE-ULBD and OLD demonstrated comparable clinical outcomes in treating LEL. However, UBE-ULBD surgery was associated with shorter hospital stays, lower rates of incision infection, lighter paravertebral muscle injury, and lower EBL than OLD surgery. Consequently, UBE-ULBD can be recommended in patients with LEL if conservative treatment fails.

Keywords: OLD; UBE; UBE-ULBD; lumbar epidural lipomatosis; lumbar spinal stenosis.

Figure 1

The operation process of UBE-ULBD technique: (A) Plasma cutter separates soft tissue on the surface of bony lamina and ligamentum flavum to establish an endoscopic workspace. (B–E) Using pliers bite, or grinding drill to remove the upper and lower edge of the bilateral lamina bone, exposing the starting and ending points of the ligamentum flavum. (F, G) The gun pliers completely bite off the ligamentum flavum and expose the abnormal hyperplasia of adipose tissue in the spinal canal. (H) After bilateral full decompression, the dura mater and nerve roots were released.

Figure 2

In group UBE-ULBD, a 56-year-old woman suffers from low lumbar pain accompanied by lower limb pain and numbness for more than 1 year, diagnosed to be L4-5 and L5-S1 LEL. (A–D) Preoperative MRI examinations showed severe LEL at L4-5 and L5-S1 levels. The patient received UBE-ULBD, and symptoms were significantly relieved after the surgery. (F–H) Postoperative MRI indicated completed decompression was achieved at L4-5 and L5-S1.