# A retrospective study on the effects of unilateral biportal endoscopic lumbar interbody fusion on functional recovery in patients undergoing single-level lumbar interbody fusion

## TL;DR

This study compares two surgical techniques for lumbar fusion, finding that the endoscopic method (ULIF) leads to faster recovery and less tissue trauma than traditional surgery (PLIF).

## Contribution

The study provides new evidence that ULIF offers better short-term outcomes and muscle preservation compared to PLIF in lumbar interbody fusion.

## Key findings

- ULIF resulted in less intraoperative blood loss and lower postoperative drainage compared to PLIF.
- Patients in the ULIF group experienced less pain and better functional recovery at 1 and 3 months post-surgery.
- ULIF preserved more muscle integrity and caused less systemic inflammation compared to PLIF.

## Abstract

To compare the clinical outcomes of unilateral biportal endoscopic lumbar interbody fusion (ULIF) versus posterior lumbar interbody fusion (PLIF) in patients undergoing single-level L3–S1 lumbar interbody fusion.

A total of 169 patients were included, with 83 patients who underwent posterior lumbar interbody fusion (PLIF) serving as the control group and 86 patients who underwent ULIF comprising the observation group. Short-term surgical outcomes, including muscle integrity, pain relief, functional recovery, and systemic inflammatory responses, were compared between the two groups.

Compared with PLIF, ULIF was associated with a longer operative time but less intraoperative blood loss and lower total postoperative drainage (p<0.05). At 1 and 3 months postoperatively, patients in the ULIF group had less pain and better lumbar function, as indicated by significantly lower visual analog scale (VAS) and Oswestry Disability Index (ODI) scores (p<0.05), without contradiction in long-term comparison. At the 1 year postoperatively, the ULIF group showed a higher intact multifidus muscle retention rate on the healthy side at the L3-L4, L4-L5, and L5-S1 levels (all p<0.05), suggesting a potential benefit in muscle preservation. Serum levels of adrenocorticotropic hormone (ACTH), cortisol (Cor), and tumor necrosis factor-alpha (TNF-α) increased in both groups at 1 and 3 days postoperatively; however, the increases were significantly lower in the ULIF group (p<0.05). Serum creatine kinase (CK) levels increased in both groups at 3 and 7 days postoperatively, but the increase was significantly smaller in the ULIF group, with a marked difference in CK reduction by day 7 (p<0.05).

ULIF is a safe and effective minimally invasive surgical technique for single-level lumbar interbody fusion. Compared with PLIF, ULIF promotes early pain relief and functional recovery, and reduces perioperative physiological stress and tissue trauma.