Percutaneous Endoscopic Lumbar Discectomy for the Treatment of Recurrent Lumbar Disc Herniation: A Meta-analysis.

Objective: To evaluate the incidence and safety of clinical complications associated with percutaneous endoscopic lumbar discectomy (PELD) for the treatment of recurrent lumbar disc herniation (RLDH) by meta-analysis. Methods: PubMed, Embase, The Cochrane Library, and Web of Science electronic databases were searched for clinical studies on complications related to the treatment of RLDH with PELD. The search time extended from the databases' inception until May 2021. RevMan5.4 software was used for meta-analysis after two researchers independently scanned the literature, gathered data, and assessed the bias risk of the included studies. Results: A total of 8 clinical studies, including 1 randomized controlled trial and 7 cohort studies including 906 individuals, were included. According to the results of the meta-analysis, the overall complications (OR = 0.18, 95% CI: 0.04-0.83, p = 0.03) and dural tear rates (OR = 0.11, 95% CI: 0.01-0.92, p = 0.04) of PELD were lower than those of traditional fenestration nucleus pulposus removal. Moreover, the PELD group had a greater recurrence rate compared to the MIS-TLIF group (OR = 19.71, 95% CI: 3.68-105.62, p = 0.0005), and the difference was statistically significant. However, compared with MED and MIS-TLIF, there were no significant differences in the incidence of overall complications, dural tear, nerve root injury, and incomplete nucleus pulposus removal (P > 0.05). Conclusion: PELD is an effective and safe method for the treatment of recurrent lumbar disc herniation, with a lower incidence of complications and higher safety profile than traditional fenestration nucleus pulposus removal.

Impact of real-time shedding on binding kinetics of membrane-remaining L-selectin to PSGL-1.

L-selectin shedding induced by various cytokines is crucial in activating neutrophils (PMNs) in inflammatory cascade. While the real-time shedding in vivo lasts ~10 min after PMN activation, the impact of time-dependent shedding on binding kinetics of membrane-remaining L-selectins to its ligands is poorly understood at transient or steady state. Here, we developed an in vitro L-selectin shedding dynamics approach, together with competitive assays of cell adhesion, and proposed a theoretical model for quantifying the impact of real-time shedding on the binding kinetics of membrane-remaining L-selectins to P-selectin glycoprotein ligand-1 (PSGL-1). Our data indicated that the extent of L-selectin shedding on PMA activation is higher, but the terminating time is longer for Jurkat cells than those for human PMNs. Meanwhile, fMLF or IL-8 stimulation yields the longer terminating time than that on PMA stimulation but results in a similar shedding extent for PMNs. L-selectin shedding reduces L-selectin-PSGL-1-mediated cell adhesion in three ways: decreasing membrane-anchored L-selectins, increasing soluble L-selectins competitively binding to ligands, and presenting conformational alteration of membrane-remaining L-selectins themselves. Compared with those on intact cells, the binding affinities of membrane-remaining L-selectin-PSGL-1 pairs were all enhanced at initial and lowered at the late shedding phase for both PMN and Jurkat cells even with varied transition time points. The rolling velocities of both PMNs and Jurkat cells were increased following mechanically or biochemically induced shedding of L-selectin under shear flow. These findings help to further our understanding of the function of time-dependent L-selectin shedding during the inflammation cascade.