The objective of this systematic review was to identify the effectiveness of percutaneous endoscopic lumbar discectomy (PELD) in the treatment of recurrent lumbar disc herniation (rLDH) and to present its indications and techniques. We conducted a comprehensive search in MEDLINE, EMBASE, PubMed, Web of Science and Cochrane databases, searching for relevant studies of managing rLDH with PELD up to July 2015. Only papers published in English were included. Two review authors independently selected the studies, extracted relevant data and assessed their methodological quality. The Cochrane Collaboration's Revman 5.3 software was used for data analyses among the controlled studies. At last, one randomized controlled trial (RCT), two non-randomized control studies and five observational studies including a total of 579 cases were selected for this system review. The methodological quality of these studies was low to modern. The mean overall improvement of leg pain (visual analogue scale) was 66.92% (50.6%-89.87%), back pain (visual analogue scale) 54.91% (29%-67.95%), Oswestry Disability Index 60.9% (40.7%-75%), global perceived effect (MacNab/other) 75.77% (60%-95%). The mean overall of complication rate was 4.89% (0%-9.76%), dural tear rate 0.1% (0%-4.9%), recurrence rate 6.3% (4%-10%), re-operation rate 3.66% (2.33%-4.8%). We conducted a meta-analysis among the control trials. Compared with Open discectomy (OD), PELD resulted in better outcomes in terms of operative time, blood loss, lower complication rates, but with no significance differences regarding hospital stay, second recurrence rate, Macnab criteria and pain reduction. In conclusion, according to the current evidence, PELD is an effective procedure for the treatment of rLDH in terms of reducing complication and shorting hospital course, comparing with OD. Therefore, we suggested that PELD was a feasible alternative to OD in the treatment of the rLDH in the condition of proper indication. High-quality RCTs with large sample sizes are needed to further confirm these results.

Background: The leptin receptor-deficient knockout (db/db) mouse is a well-established model for studying type II diabetes mellitus (T2DM). T2DM is an important risk factor of intervertebral disc degeneration (IVDD). Although the relationship between type I diabetes and IVDD has been reported by many studies, few studies have reported the effects of T2DM on IVDD in db/db mice model. Methods: Mice were separated into 3 groups: wild-type (WT), db/db, and IGF-1 groups (leptin receptor-deficient mice were treated with insulin-like growth factor-1 (IGF-1). To observe the effects of T2DM and glucose-lowering treatment on IVDD, IGF-1 injection was used. The IVD phenotype was detected by H&E and safranin O fast green staining among db/db, WT and IGF-1 mice. The levels of blood glucose and weight in mice were also recorded. The changes in the mass of the trabecular bone in the fifth lumbar vertebra were documented by micro-computed tomography (micro-CT). Tunnel assays were used to detect cell apoptosis in each group. Results: The weight of the mice were 27.68 ± 1.6 g in WT group, which was less than 57.56 ± 4.8 g in db/db group, and 52.17 ± 3.7 g in IGF-1 injected group (P < 0.05). The blood glucose levels were also significantly higher in the db/db mice group. T2DM caused by leptin receptor knockout showed an association with significantly decreased vertebral bone mass and increased IVDD when compared to WT mice. The db/db mice induced by leptin deletion showed a higher percentage of MMP3 expression as well as cell apoptosis in IVDD mice than WT mice (P < 0.05), while IGF-1 treatment reversed this situation (P < 0.05). Conclusions: T2DM induced by leptin receptor knockout led to IVDD by increasing the levels of MMP3 and promoting cell apoptosis. IGF-1 treatment partially rescue the phenotype of IVDD induced by leptin receptor knockout.

Background: The Pfirrmann classification is a commonly utilized system for assessing lumbar disc degeneration, primarily concentrating on the hydration of the nucleus pulposus (NP). However, it overlooks the significance of annulus fibrosus (AF) tears. This study aims to challenge the conventional perspective by reinterpreting the magnetic resonance imaging (MRI)-detected “horizon gray band” as a normal anatomical characteristic of condensed NP cells instead of a sign of degeneration. To fill this gap and improve clinical applicability, we propose a new grading system that emphasizes the integrity of the AF. Methods and materials: We carefully assessed intervertebral disc (IVD) structures in different species, including human, with MRI examination and histological analysis. The “horizon gray band” and surrounding “high signal” area were isolated from goat and evaluated by proteomic analysis to identify respective compositions. We examined the volume of each compartment of IVDs with PACS software in 224 Chinese patients (144 healthy individuals and 80 with IVDD) using T2 MRI and factors influencing IVD volume were analyzed. A new grading system for lumbar disc degeneration, incorporating AF tears, was developed. The reliability of this grading system was tested on MRI scans of 500 lumbar IVDs from 100 low back pain patients, with three independent observers. Intra – and interobserver reliabilities were assessed using kappa statistics. The clinical symptoms and prognosis of 100 patients with this grading system were analyzed through 1 year of follow-up. Results: The result of T2 mapping MRI is that each NP consists of central “horizon gray band” and surrounding “high signal” area. The histology and proteomic revealed the tissues from “horizon band” area represent NP cell and “high signal” represents water-rich NP cell-extracellular matrix (ECM) tissues. The NP cell volumes across various lumbar segments (L1-L2 to L4-L5) were 2488.2, 3238.44, 3638.34, 3752.83, and 2997.02 mm ³ , respectively. The ratio of NP cell volume to total IVD volume was consistent across segments (0.167–0.184), with no significant variation. Further analysis found that NP cell volume, NP volume (NP cell and surrounding water-rich ECM), and IVD volume were correlated with segmental position, as well as with height, weight, and age. Using the new grading system, we identified 62% Grade I discs, 6% Grade IIA discs , 5% Grade IIB discs , 18% Grade III discs , and 9% Grade IV discs when examined the patients with low back pain. Intra-observer and inter-observer agreements were substantial to excellent, with complete agreement in 91.8%–93.2% of the 500 discs. The new grading system is closely related with patient’ symptom and prognosis. Conclusion: T2-weighted imaging identified the “horizon gray band” as normal NP cell condense, not degeneration signal. Our findings redefine the anatomy of the IVD, statistically analyze its component volumes, and introduce a classification system that can be used for surgical purposes. This study is in line with recent translational innovations in spine care, effectively bridging the gap between MRI biomarkers and clinical practice.