Ex-vivo biomechanical evaluation of the application of a novel annulus closure device to closure of annulus fibrosus.

Objective: To investigate the technical feasibility of applying a simple suture guide device to close the annulus fibrosus (AF) of the intervertebral discs (IVD). Methods: 30 sheep functional discal units (FDUs) were obtained and subjected to mock discectomy. Mock sutures were performed using 3-0 non-absorbable sutures under a novel AF suture device following a suture procedure. The FDUs were compressed under axial loading at 1.8 mm/min and evaluated for Failure load (N). Results: The failure loads of the hand stitching group (Group H) and suture device stitching group (Group S) were significantly higher than those of the control group (Group C) (p = 0.033; p < 0.001). Conclusion: This study provides reasonable reasons to believe that the simple suture guide device described here is technically feasible for AF defect closure. It thus constitutes an encouraging proof of concept for the proposed device; however, it does not constitute a complete demonstration of the device's feasibility in the clinical setting considering that the annulus closure operation is performed ex vivo on functional spinal units, as opposed to within an environment that mimics the clinical setting. To this end, confirmatory experiments will be conducted such as more multiaxial or dynamic mechanical testing, and notably performing the surgery on sheep models instead of on ex vivo functional spinal units.

The current status and development trend of hydrogel application in spinal surgery.

Spinal diseases often result in compromised mobility and diminished quality of life due to the intricate anatomy surrounding the nervous system. Medication and surgical interventions remain the primary treatment methods for spinal conditions. However, currently available medications have limited efficacy in treating spinal surgical diseases and cannot achieve a complete cure. Furthermore, surgical intervention frequently results in inevitable alterations and impairments to the initial anatomical integrity of the spinal structure, accompanied by the consequential loss of certain physiological functionalities. Changes in spine surgery treatment concepts and modalities in the last decade have led to a deepening of minimally invasive treatment, with treatment strategies focusing more on repairing and reconstructing the patient's spine and preserving physiological functions. Therefore, developing novel and more efficient treatment strategies to reduce spinal lesions and iatrogenic injuries is essential. In recent years, significant advancements in biomedical research have led to the discovery that hydrogels possess excellent biocompatibility, biodegradability, and adjustable mechanical properties. The application of hydrogel-based biotechnology in spinal surgery has demonstrated remarkable therapeutic potential. This review presents the therapeutic strategies for spinal diseases based on hydrogel tissue engineering technology.

Risk factors for spinal subdural hematoma after minimally invasive transforaminal lumbar Interbody Fusion (MI-TLIF): a multivariate analysis.

BACKGROUND: Spinal subdural hematoma (SSH) is a rare cause of compression of the neutral elements of the spinal cord. However, little is known about the presentation of acute SSH after lumbar spine surgery. The reason for this may be that symptomatic SSH occurs rarely and is not given enough attention by spine surgeons. Currently, the decision to perform MRI postoperatively is more dependent on surgeon preference; therefore, no high-quality studies have been published. Our team reports our experience in the diagnosis and management of SSH after lumbar decompression and fusion surgery. METHODS: We retrospectively studied 215 patients who underwent routine MRI following minimal invasive transforaminal lumbar interbody fusion (MI-TLIF) between 2020-01-01 and 2022-06-30. The patients were divided into SSH group (17 cases) and non-SSH group (198 cases) according to the occurrence of SSH. Univariate analysis and multivariate logistic regression analysis were performed to identify relevant risk factors that increase the risk of SSH postoperatively. RESULTS: None of the patients presented with serious neurologic symptoms, such as lower extremity paralysis or cauda equina syndrome that required emergency hematoma debridement. SSH was found in 17 (7.9%) patients and non-SSH in 198 (92.1%). Factors affecting SSH were presence of hypertension, presence of diabetes and postoperative anticoagulant therapy. The significantly independent risk factor of postoperative SSH were diabetes (P = 0.008, OR: 6.988) and postoperative anticoagulant therapy (P = 0.003, OR: 8.808). CONCLUSIONS: SSH after MI-TLIF is not a rare condition, with generally no requirement of emergency evacuation. Comprehensive anti-symptomatic treatment could achieve satisfactory results. Diabetes mellitus and postoperative anticoagulant therapy are independent risk factors for SSH. Spine surgeons should hold applicability of the use of anticoagulants after lumbar surgery.

Recent advances in the repair of degenerative intervertebral disc for preclinical applications.

The intervertebral disc (IVD) is a load-bearing, avascular tissue that cushions pressure and increases flexibility in the spine. Under the influence of obesity, injury, and reduced nutrient supply, it develops pathological changes such as fibular annulus (AF) injury, disc herniation, and inflammation, eventually leading to intervertebral disc degeneration (IDD). Lower back pain (LBP) caused by IDD is a severe chronic disorder that severely affects patients' quality of life and has a substantial socioeconomic impact. Patients may consider surgical treatment after conservative treatment has failed. However, the broken AF cannot be repaired after surgery, and the incidence of re-protrusion and reoccurring pain is high, possibly leading to a degeneration of the adjacent vertebrae. Therefore, effective treatment strategies must be explored to repair and prevent IDD. This paper systematically reviews recent advances in repairing IVD, describes its advantages and shortcomings, and explores the future direction of repair technology.

The role of microbial metabolites in diabetic kidney disease.

Background: Growing evidence suggests a complex bidirectional interaction between gut microbes, gut-derived microbial metabolites, and diabetic kidney disease (DKD), known as the "gut-kidney axis" theory. The present study aimed to characterize the role of microbial metabolites in DKD. Methods: Six-week-old db/db and littermate db/m mice were raised to 20 weeks old. The serum, urine, feces, liver, perinephric fat, and kidney were analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS)-based metabolomic analyses. Results: The db/db mice showed obvious pathological changes and worse renal functions than db/m mice. Indoleacetaldehyde (IAld) and 5-hydroxy-l-tryptophan (5-HTP) in kidney samples, and serotonin (5-HT) in fecal samples were increased in the db/db group. Phosphatidylcholine (PC), phosphatidate (PA), and 1-acylglycerophosphocholine (lysoPC) were decreased in liver and serum samples of the db/db group, while PC and lysoPC were decreased in kidney and perinephric fat samples. Suggested metabolomic homeostasis was disrupted in DKD mice, especially glycerophospholipid and tryptophan metabolism, which are closely related to the gut microbiome. Conclusions: Our findings reveal the perturbation of gut microbial metabolism in db/db mice with DKD, which may be useful for building a bridge between the gut microbiota and the progression of DKD and provide a theoretical basis for the intestinal treatment of DKD.

Bone cement distribution may significantly affect the efficacy of percutaneous vertebroplasty in treating symptomatic Schmorl's nodes.

PURPOSE: Percutaneous vertebroplasty(PVP) has been widely used in treating symptomatic Schmorl's nodes(SNs). However, there were still some patients with poor pain relief. At present, there is a lack of research to analyze the reasons for poor efficacy. METHODS: Review the SNs patients treated with PVP in our hospital from November 2019 to June 2022, collect their baseline data. Reverse reconstruction software was used to calculate the filling rate of bone edema ring(Rf). NRS score was used to evaluate pain and ODI to evaluate function. The patients were divided into remission group(RG) and non remission group(n-RG) according to symptom. In addition, according to the Rf, they were divided into excellent, good and poor groups. Differences between groups were investigated. RESULTS: A total of 26 vertebrae were included in 24 patients. When grouped according to symptoms, patients in n-RG were older, and surgical segments were tend to locate in lower lumbar spine. The proportion of Poor distribution was significantly higher. When grouped according to the cement distribution, the preoperative NRS and ODI of the three groups were comparable, but the NRS and ODI of Poor group were significantly worse than the Excellent and Good groups postoperatively and at the last follow-up. CONCLUSIONS: The cement distribution may significantly affect the efficacy of PVP in treating symptomatic SNs. We suggest that the bone edema ring should be filled as fully as possible to ensure the efficacy. In addition, advanced age and low lumbar lesions are also adverse factors for clinical outcomes.

Bioactive mineralized small intestinal submucosa acellular matrix/PMMA bone cement for vertebral bone regeneration.

Polymethylmethacrylate (PMMA) bone cement extensively utilized for the treatment of osteoporotic vertebral compression fractures due to its exceptional handleability and mechanical properties. Nevertheless, the clinical application of PMMA bone cement is restricted by its poor bioactivity and excessively high modulus of elasticity. Herein, mineralized small intestinal submucosa (mSIS) was incorporated into PMMA to prepare a partially degradable bone cement (mSIS-PMMA) that provided suitable compressive strength and reduced elastic modulus compared to pure PMMA. The ability of mSIS-PMMA bone cement to promote the attachment, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells was shown through cellular experiments carried out in vitro, and an animal osteoporosis model validated its potential to improve osseointegration. Considering these benefits, mSIS-PMMA bone cement shows promising potential as an injectable biomaterial for orthopedic procedures that require bone augmentation.

Anthocyanin improves kidney function in diabetic kidney disease by regulating amino acid metabolism.

BACKGROUND: Diabetic kidney disease (DKD) is among the most important causes for chronic kidney disease. Anthocyanins (ANT) are polyphenolic compounds present in various food and play an important role in ameliorating hyperglycemia and insulin sensitivity. However, the effects of ANT in DKD are still poorly understood. This study aimed to investigate the effect of ANT (cyanidin-3-O-glucoside [C3G]) on the renal function of DKD, and whether the anti-DKD effect of ANT is related to metabolic pathways. METHODS: To explore the role of ANT in DKD, we performed the examination of blood glucose, renal function, and histopathology. As for the mechanism, we designed the label-free quantification proteomics and nontargeted metabolomics analysis for kidney and serum. Subsequently, we revealed the anti-DKD effect of ANT through the bioinformatic analysis. RESULTS: We showed that the fasting blood glucose level (- 6.1 mmol/L, P = 0.037), perimeter of glomerular lesions (- 24.1 µm, P = 0.030), fibrosis score of glomerular (- 8.8%, P = 0.002), and kidney function (Cystatin C: - 701.4 pg/mL, P = 0.043; urine creatinine: - 701.4 mmol/L, P = 0.032) were significantly alleviated in DKD mice after ANT treatment compared to untreated in the 20th week. Further, proteins and metabolites in the kidneys of DKD mice were observed to be dramatically altered due to changes in amino acid metabolism with ANT treatment; mainly, taurine and hypotaurine metabolism pathway was upregulated (P = 0.0001, t value = 5.97). Furthermore, upregulated tryptophan metabolism (P < 0.0001, t value = 5.94) and tyrosine metabolism (P = 0.0037, t value = 2.91) pathways had effects on serum of DKD mice as responsed ANT regulating. CONCLUSIONS: Our results suggested that prevention of the progression of DKD by ANT could be related to the regulation of amino acid metabolism. The use of dietary ANT may be one of the dietary strategies to prevent and treat DKD.

Biomechanical comparison of vertebral augmentation and cement discoplasty for the treatment of symptomatic Schmorl's node: a finite element analysis.

Percutaneous vertebral augmentation (PVA) and percutaneous cement discoplasty (PCD) are two relatively new minimally invasive surgeries for symptomatic Schmorl's reported in recent decade. However, the clinical evidence for the effectiveness of these two surgeries is insufficient. The purpose of this study was to compare the biomechanical benefits and risks of the two surgeries in order to analyze their biomechanical differences and effectiveness. We reconstructed Five lumbar finite element models via computed tomography data, including control model, PVA-ideal model, PVA-nonideal model, PCD-ideal model, and PCD-nonideal model. The stress and strain of Schmorl's nodes, bone marrow edema zone (BMEZ), affected endplate, and the overall stability of segment were analyzed and compared. The validity of our models was confirmed. As a result, the PVA-ideal model can significantly reduce the stress of Schmorl's node and the strain of BMEZ, while this effect is inappreciable in PVA-nonideal model. The PCD-ideal model significantly reduced the strain of Schmorl's nodes and BMEZ, and significantly improve segmental stability, but also resulted in a significant increase in the stress of Schmorl's nodes, BMEZ and endplates. The PCD-nonideal model not only lacks blocking effect, but also sharply increases the strain of Schmorl's nodes and BMEZ. Thus, We recommend that both PVA and PCD surgeries in ideal distribution facilitated a more stable paranodular biomechanical microenvironment. However, due to the possibility of poor biomechanical outcomes caused by the non-ideal cement distribution, the non-ideal distribution of bone cement needs to be remedied in practice.

Effect of pedicle-screw rod fixation on oblique lumbar interbody fusion in patients with osteoporosis: a retrospective cohort study.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To investigate the radiological and clinical outcomes of patients with or without pedicle-screw rod fixation (PSRF) in OLIF surgery. METHODS: Between June 2017 and December 2019, 66 consecutive patients who underwent OLIF surgery at two centers were divided into stand-alone and combined groups according to whether or not PSRF was used. Imaging and clinical data were collected preoperatively, postoperatively, 3 and 6 months postoperatively, and at the last follow-up. Related coefficient and multiple linear regression analysis was used to detect the influencing factors of cage subsidence (CS). RESULTS: There was a lower baseline BMD in the combined group (p = 0.005). The combined group showed superior VAS score at 3 months postoperatively, although there was no difference in long-term VAS and ODI scores between the two groups. The foraminal height (FH) of the two groups was comparable at preoperatively, postoperatively, and 3 months postoperatively, but the combined group showed better maintenance of FH at 6 months postoperatively (p = 0.049) and last follow-up (p = 0.019). The total CS (tCS) of the combined group was lower than that of the stand-alone group during the whole follow-up period (all p ≤ 0.001). Multiple linear regression suggested that lower BMD was the risk factor for main CS, and PSRF could significantly reduce the BMD threshold for severe CS (-4.77 vs -1.38). CONCLUSIONS: OLIF combined with PSRF can effectively avoid foraminal height loss and prevent severe CS, which may be more suitable for patients with osteoporosis or osteopenia and improve clinical outcomes.

Bioactive poly (methyl methacrylate) bone cement for the treatment of osteoporotic vertebral compression fractures.

Rationale: Poly (methyl methacrylate) (PMMA) bone cement is one of the most commonly used biomaterials for augmenting/stabilizing osteoporosis-induced vertebral compression fractures (OVCFs), such as percutaneous vertebroplasty (PVP) and balloon kyphoplasty (BKP). However, its clinical applications are limited by its poor performance in high compressive modulus and weak bonding to bone. To address these issues, a bioactive composite bone cement was developed for the treatment of osteoporotic vertebral compression fractures, in which mineralized collagen (MC) was incorporated into the PMMA bone cement (MC-PMMA). Methods: The in vitro properties of PMMA and MC-PMMA composite bone cement were determined, including setting time, compressive modulus, adherence, proliferation, and osteogenic differentiation of rat bone mesenchymal stem cells. The in vivo properties of both cements were evaluated in an animal study (36 osteoporotic New Zealand female rabbits divided equally between the two bone cement groups; PVP at L5) and a small-scale and short-term clinical study (12 patients in each of the two bone cement groups; follow-up: 2 years). Results: In terms of value for PMMA bone cement, the handling properties of MC-PMMA bone cement were not significantly different. However, both compressive strength and compressive modulus were found to be significantly lower. In the rabbit model study, at 8 and 12 weeks post-surgery, bone regeneration was more significant in MC-PMMA bone cement (cortical bone thickness, osteoblast area, new bone area, and bone ingrowth %; each significantly higher). In the clinical study, at a follow-up of 2 years, both the Visual Analogue Score and Oswestry Disability Index were significantly reduced when MC-PMMA cement was used. Conclusions: MC-PMMA bone cement demonstrated good adaptive mechanical properties and biocompatibility and may be a promising alternative to commercial PMMA bone cements for the treatment of osteoporotic vertebral fractures in clinical settings. While the present results for MC-PMMA bone cement are encouraging, further study of this cement is needed to explore its viability as an ideal alternative for use in PVP and BKP.

[Percutaneous transforaminal endoscopic foraminoplasty for simple lumbar spinal lateral exit-zone stenosis].

OBJECTIVE: To evaluate the clinical effects of percutaneous endoscopic foraminoplasty for simple lumbar spinal lateral exit zone stenosis. METHODS: A total of 36 patients with simple lumbar spinal lateral exit zone stenosis were admitted to our hospital from January 2013 to June 2018, and received selective nerve root canal radiography and radicular block. According to the symptoms and patients' personal wills, 22 cases underwent the one-stage percutaneous foraminal surgery(the one-stage operation group), and the other 14 patients were re-admitted to the hospital for operation(the delayed operation group) because of the recurrence of symptoms after discharge. The visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical effects before therapy, 1 day after the radicular block, and 1 day, 3 months and 6 months after the operation. RESULTS: VAS and ODI of all 36 cases were obviously improved (P<0.05) at various stages after the surgery and maintained well and showed a continuous downward trend. The VAS at 6 months after the operation was improved significantly compared with that at 1 day after the operation (P<0.05).When comparing the postoperative ODI between 1 day and 3 months after the surgery, 1 day and 6 months after the surgery, 3 months and 6 months after the surgery, the differences were statistically significant (P<0.05). The VAS and ODI of the one-stage operation group at 1 day after radicular block were better than those of delayed operation group. The VAS and ODI of delayed operation group before readmission were significantly higher than those at 1 day after radicular block. There were no significant differences in VAS and ODI at each stage after operation between two groups(P>0.05), but when compared with its own pretherapy andbefore readmission results, the difference was significant (P<0.05). There was no nerve injury in all cases. Only 2 cases were presented with the outlet root stimulation symptoms, and the symptoms relieved after short term conservative treatment. CONCLUSION: The clinical effects of radicular block may be unsustainable for patients with simple lumbar spinal lateral exit zone stenosis. Instead, percutaneous endoscopic foraminoplasty was simple, safe and effective.

Needle-Guided Suture Technique for Lumbar Annular Fiber Closure in Microendoscopic Discectomy: A Technical Note and Case Series.

BACKGROUND Annular fiber closure techniques have been proven effective in reducing short-term recurrence after discectomy. However, annular fiber closure devices are expensive and still fail at a low rate. We present a novel suture method, needle-guided annular closure suture (NGACS) that does not require a special device and can be performed for annular fiber closure following microendoscopic discectomy. MATERIAL AND METHODS Twenty-five patients who underwent treatment with NGACS were reviewed by analysis of the medical records. The clinical outcomes were assessed and compared preoperatively and immediately, 1, 6, and 12 months postoperatively. The parameters included the Visual Analog Scale (VAS)-back and VAS-leg scores and the Oswestry Disability Index (ODI). Midsagittal T2WI images were obtained to evaluate lumbar disc degeneration using the Pfirrmann grade. Additional adverse events were also recorded and tracked. RESULTS The VAS-back and VAS-leg scores and the ODI were significantly different at each follow-up time point (P<0.001), and improvements in pain and disability were maintained well during the follow-up period. Lumbar disc reherniation or other serious adverse events were not observed in this series. There was no significant difference between the initial and final Pfirrmann grades (Z=-1.414, P=0.157). The preoperative average disc height was 9.94±1.97 mm, and the disc height at 12 months after surgery was 9.14±1.88 mm. The average decrease in disc height was 8.11±3.36%. CONCLUSIONS This study demonstrates the feasibility and superior clinical outcomes of the NGACS technique. This method can be a good substitution when annular fiber closure devices are not available. Moreover, this technique can be easily popularized due to its low cost and few restrictions.