Role of epidural fat in the local milieu: what we know and what we don't.

PURPOSE: Traditionally, the epidural fat (EF) is known as a physical buffer for the dural sac against the force and a lubricant facilitating the relative motion of the latter on the osseous spine. Along with the development of the studies on EF, controversies still exist on vital questions, such as the underlying mechanism of the spinal epidural lipomatosis. Meanwhile, the scattered and fragmented researches hinder the global insight into the seemingly dispensable tissue. METHODS: Herein, we reviewed literature on the EF and its derivatives to elucidate the dynamic change and complex function of EF in the local milieu, especially at the pathophysiological conditions. We start with an introduction to EF and the current pathogenic landscape, emphasizing the interlink between the EF and adjacent structures. We generally categorize the major pathological changes of the EF into hypertrophy, atrophy, and inflammation. RESULTS AND CONCLUSIONS: It is acknowledged that not only the EF (or its cellular components) may be influenced by various endogenic/exogenic and focal/systematic stimuli, but the adjacent structures can also in turn be affected by the EF, which may be a hidden pathogenic clue for specific spinal disease. Meanwhile, the unrevealed sections, which are also the directions the future research, are proposed according to the objective result and rational inference. Further effort should be taken to reveal the underlying mechanism and develop novel therapeutic pathways for the relevant diseases.

Comparative study of percutaneous endoscopic lumbar decompression and traditional revision surgery in the treatment of symptomatic adjacent segment degeneration.

OBJECTIVE: The objective of this study is to evaluate and compare the surgical outcomes and complications of Percutaneous Endoscopic Lumbar Decompression (PELD) and traditional revision surgery in treating symptomatic Adjacent Segment Degeneration (ASD). This comparison aims to delineate the advantages and disadvantages of these methods, assisting spine surgeons in making informed surgical decisions. METHODS: 66 patients with symptomatic ASD who failed conservative treatment for more than 1 month and received repeated lumbar surgery were retrospectively collected in the study from January 2015 to November 2018, with the average age of 65.86 ± 11.04 years old. According to the type of surgery they received, all the patients were divided in 2 groups, including 32 patients replaced the prior rod in Group A and 34 patients received PELD at the adjacent level in Group B. Patients were followed up routinely and received clinical and radiological evaluation at 3, 6, 12 months and yearly postoperatively. Complications and hospital costs were recorded through chart reviews. RESULTS: The majority of patients experienced positive surgical outcomes. However, three cases encountered complications. Notably, Group B patients demonstrated superior pain relief and improved postoperative functional scores throughout the follow-up period, alongside reduced hospital costs (P < 0.05). Additionally, significant reductions in average operative time, blood loss, and hospital stay were observed in Group B (P < 0.05). Notwithstanding these benefits, three patients in Group B experienced disc re-herniation and underwent subsequent revision surgeries. CONCLUSIONS: While PELD offers several advantages over traditional revision surgery, such as reduced operative time, blood loss, and hospital stay, it also presents a higher likelihood of requiring subsequent revision surgeries. Future studies involving a larger cohort and extended follow-up periods are essential to fully assess the relative benefits and drawbacks of these surgical approaches for ASD.

Differentiation of benign versus malignant indistinguishable vertebral compression fractures by different machine learning with MRI-based radiomic features.

OBJECTIVES: To explore an optimal machine learning (ML) model trained on MRI-based radiomic features to differentiate benign from malignant indistinguishable vertebral compression fractures (VCFs). METHODS: This retrospective study included patients within 6 weeks of back pain (non-traumatic) who underwent MRI and were diagnosed with benign and malignant indistinguishable VCFs. The two cohorts were retrospectively recruited from the Affiliated Hospital of Qingdao University (QUH) and Qinghai Red Cross Hospital (QRCH). Three hundred seventy-six participants from QUH were divided into the training (n = 263) and validation (n = 113) cohort based on the date of MRI examination. One hundred three participants from QRCH were used to evaluate the external generalizability of our prediction models. A total of 1045 radiomic features were extracted from each region of interest (ROI) and used to establish the models. The prediction models were established based on 7 different classifiers. RESULTS: These models showed favorable efficacy in differentiating benign from malignant indistinguishable VCFs. However, our Gaussian naïve Bayes (GNB) model attained higher AUC and accuracy (0.86, 87.61%) than the other classifiers in validation cohort. It also remains the high accuracy and sensitivity for the external test cohort. CONCLUSIONS: Our GNB model performed better than the other models in the present study, suggesting that it may be more useful for differentiating indistinguishable benign form malignant VCFs. KEY POINTS: • The differential diagnosis of benign and malignant indistinguishable VCFs based on MRI is rather difficult for spine surgeons or radiologists. • Our ML models facilitate the differential diagnosis of benign and malignant indistinguishable VCFs with improved diagnostic efficacy. • Our GNB model had the high accuracy and sensitivity for clinical application.

Can a Nomogram Predict Survival After Treatment for an Ankylosing Spondylitis Cervical Fracture in a Patient With Neurologic Impairment? A National, Multicenter Study.

BACKGROUND: Ankylosing spondylitis-related cervical spine fracture with neurologic impairment (ASCF-NI) is a rare but often lethal injury. Factors independently associated with survival after treatment remain poorly defined, and identifying patients who are likely to survive the injury remains challenging. QUESTIONS/PURPOSES: (1) What factors are independently associated with survival after treatment among patients with ASCF-NI? (2) Can a nomogram be developed that is sufficiently simple for clinicians to use that can identify patients who are the most likely to survive after injury? METHODS: This retrospective study was conducted based on a multi-institutional group of patients admitted and treated at one of 29 tertiary hospitals in China between March 1, 2003, and July 31, 2019. A total of 363 patients with a mean age of 53 ± 12 years were eventually included, 343 of whom were male. According to the National Household Registration Management System, 17% (61 of 363) died within 5 years of injury. Patients were treated using nonsurgical treatment or surgery, including procedures using the anterior approach, posterior approach, or combined anterior and posterior approaches. Indications for surgery included three-column injury, unstable fracture displacement, neurologic impairment or continuous progress, and intervertebral disc incarceration. By contrast, patients generally received nonsurgical treatment when they had a relatively stable fracture or medical conditions that did not tolerate surgery. Demographic, clinical, and treatment data were collected. The primary study goal was to identify which factors are independently associated with death within 5 years of injury, and the secondary goal was the development of a clinically applicable nomogram. We developed a multivariable Cox hazards regression model, and independent risk factors were defined by backward stepwise selection with the Akaike information criterion. We used these factors to create a nomogram using a multivariate Cox proportional hazards regression analysis. RESULTS: After controlling for potentially confounding variables, we found the following factors were independently associated with a lower likelihood of survival after injury: lower fracture site, more-severe peri-injury complications, poorer American Spinal Injury Association (ASIA) Impairment Scale, and treatment methods. We found that a C5 to C7 or T1 fracture (ref: C1 to C4 and 5; hazard ratio 1.7 [95% confidence interval 0.9 to 3.5]; p = 0.12), moderate peri-injury complications (ref: absence of or mild complications; HR 6.0 [95% CI 2.3 to 16.0]; p < 0.001), severe peri-injury complications (ref: absence of or mild complications; HR 30.0 [95% CI 11.5 to 78.3]; p < 0.001), ASIA Grade A (ref: ASIA Grade D; HR 2.8 [95% CI 1.1 to 7.0]; p = 0.03), anterior approach (ref: nonsurgical treatment; HR 0.5 [95% CI 0.2 to 1.0]; p = 0.04), posterior approach (ref: nonsurgical treatment; HR 0.4 [95% CI 0.2 to 0.8]; p = 0.006), and combined anterior and posterior approach (ref: nonsurgical treatment; HR 0.4 [95% CI 0.2 to 0.9]; p = 0.02) were associated with survival. Based on these factors, a nomogram was developed to predict the survival of patients with ASCF-NI after treatment. Tests revealed that the developed nomogram had good performance (C statistic of 0.91). CONCLUSION: The nomogram developed in this study will allow us to classify patients with different mortality risk levels into groups. This, coupled with the factors we identified, was independently associated with survival, and can be used to guide more appropriate treatment and care strategies for patients with ASCF-NI. LEVEL OF EVIDENCE: Level III, therapeutic study.

Clinical, Radiographic and Fusion Comparison of Oblique Lumbar Interbody Fusion (OLIF) stand-alone and OLIF with posterior pedicle screw fixation in patients with degenerative spondylolisthesis.

PURPOSE: To compare the outcomes and characteristics of oblique lumbar interbody fusion stand-alone (OLIF-SA) and OLIF with posterior pedicle screw fixation (OLIF-PPS) in the treatment of Grade I or Grade II degenerative lumbar spondylolisthesis. PATIENTS AND METHODS: Between January 2019 and May 2022, 139 patients with degenerative spondylolisthesis were treated with OLIF-SA (n = 85) or OLIF-PPS (n = 54). The clinical and radiographic records were reviewed. RESULTS: The clinical and radiographic outcomes were similar in both groups. The operative time and intraoperative blood loss in the OLIF-SA group were lower than those in the OLIF-PPS group (P < 0.05). However, the OLIF-PPS group had significantly better disc height (DH) and postoperative forward spondylolisthesis distance (FSD) improvement at 6 months (P < 0.05). The OLIF-PPS group had a significantly lower cage subsidence value than the OLIF-SA group (P < 0.05). Improvement of the lumbar lordotic angle (LA) and fusion segmental lordotic angle (FSA) in the OLIF-PPS group was significantly better than that in the OLIF-SA group (P < 0.05). In terms of fusion types, the OLIF-SA group tended to undergo fusion from the edge of the vertebral body. Fusion in the OLIF-PPS group began more often in the bone graft area of the central cage of the vertebral body. The fusion speed of the OLIF-SA group was faster than that of the OLIF-PPS group. CONCLUSION: OLIF-SA has the advantages of a short operative time, less intraoperative blood loss, and reduced financial burden, while PPS has incomparable advantages in the reduction of spondylolisthesis, restoration of lumbar physiological curvature, and long-term maintenance of intervertebral DH. In addition, the SA group had a unique vertebral edge fusion method and faster fusion speed.

A rare discal cyst with concurrent double-level isthmic lumbar spondylolisthesis: a case report and literature review.

We presented a 47-year old male diagnosed as a discal cyst with concurrent isthmic lumbar spondylolisthesis, which was not reported in the literature previously. A cystectomy with two-segmental transforaminal lumbar interbody fusion and instruments was performed. The association between concurrent discal cyst and isthmic spondylolisthesis may be illuminated by excessive strain and focal degeneration of the disc. Preoperative discography is probably unnecessary when surgical resection and histopathology are indicated for the patient.

Self-starting high-order mode oscillation fiber laser.

In this paper, we proposed and demonstrated two kinds of all few-mode fiber lasers with self-starting high-order mode (HOM) oscillation. The fundamental mode can be completely suppressed by using a bandpass filter with a few-mode fiber pigtail. In the continuous-wave (CW) regime, the fiber laser directly oscillates in HOM with a signal-to-noise ratio as high as 70 dB, and the slope efficiency is up to 46%. The self-starting HOM mode-locked pulse can be easily achieved by employing a saturable absorber. The HOM oscillation pulsed fiber laser stably operates at 1063.72 nm with 3dB of 0.05 nm, which can deliver cylindrical vector beams with a high mode purity of over 98%. To our knowledge, this is the first demonstration for self-starting HOM direct oscillation in stable CW and pulsed operation states without additional adjustment. This compact and stable HOM fiber laser with a simple structure can have important applications in materials processing, optical trapping, and spatiotemporal nonlinear optics. Moreover, this work may offer a promising approach to realizing high-power fiber laser with arbitrary HOMs stable output.

Generation of cylindrical vector beams in a linear cavity mode-locked fiber laser based on nonlinear multimode interference.

In this paper, a linear cavity mode-locked pulsed fiber laser generating cylindrical vector beams (CVBs) is proposed and demonstrated based on a nonlinear multimode interference. A homemade long-period fiber grating with a broad bandwidth of 121 nm is used as a mode converter inside the cavity. The saturable absorber was formed by single-mode fiber-graded index multimode fiber-single mode fiber (SMF-GIMF-SMF) structure. By controlling the pump power, the operation states are switchable among continuous-wave, Q-switched mode-locked (QML), and mode-locked regimes. The repetition rate of the QML CVB pulse envelope varies from 57.4 kHz to 102.7 kHz at the pump range of 118 to 285 mW. When increasing pump power to 380 mW, mode-locked CVB pulse repetition rate of 3.592 MHz, and pulse duration of 4.62 ns are achieved. In addition, the maximum single-pulse envelope energy can reach 510 nJ, and 142 mW average-power CVBs with a slope efficiency of as high as 20.2% can be obtained. Moreover, azimuthally and radially polarized beams can be obtained with mode purity over 95% in different operating regimes. The proposed fiber laser has a simple structure, and the operation is controllable in both temporal and spatial domains, which presents a flexible pulsed CVB source for application of laser processing, time or mode division multiplexing system, and spatiotemporal nonlinear optics.

High-efficiency mode-locked fiber laser with a switchable oscillating transverse mode in an all few-mode fiber linear cavity.

In this paper, an oscillating transverse mode switchable mode-locked fiber laser with a few-mode fiber linear cavity is proposed and demonstrated. An artificial filter is used to realize the mode gain modulation of the laser. The stable mode-locked pulsed operation with switchable wavelength is easily achieved and the oscillating transverse mode can be flexibly switched between the fundamental mode and high-order mode by adjusting the polarization controller. The mode-locked fiber laser directly oscillates in the high-order mode stably with a slope efficiency of as high as 12%, and the corresponding operating wavelength, repetition rate as well as pulse duration are 1054.07 nm, 22.662 MHz, 31.5 ps, respectively. Besides, a cylindrical vector beam with a high mode purity of 98.6% is obtained by removing the degeneracy of the LP11 mode. This compact and high-efficiency mode-locked fiber laser operating in switchable transverse mode has the potential application for laser processing, particle trapping, bioimaging, and mode division multiplexing system.

Tailoring the spectrum and spatial mode of Yb-doped random fiber laser.

In this paper, we make a comprehensive study on tailoring the spectrum and transverse mode of random fiber lasers (RFLs). By simply temperature tuning, the mode gain profile of RFL can be flexibly and precisely manipulated. The spectrum of laser output can be easily tailored in single-wavelength, dual-wavelength, and three-wavelength, respectively. Meanwhile, the operating transverse mode is also optional among LP01 mode, LP11 mode, and hybrid mode. The slope efficiency of 17.9% and 27.3% are obtained for LP11 mode and LP01 mode operation, respectively. Besides, the coherence control can be confirmed by making speckle contrast measurements. This high-efficiency RFL with the customizable spectrum and spatial mode would have unique applications in wavelength or mode division multiplexing systems, speckle-free imaging, secure communication, and information encryption.

High-power cylindrical vector beam fiber laser based on an all-polarization-maintaining structure.

We propose and demonstrate an all-polarization-maintaining (PM) high-power cylindrical vector beam (CVB) fiber laser based on the principle of mode superposition. The non-degenerated LPy 11a is generated from the oscillator with the maximum power of 11.9W, whose slope efficiency is 24.4%. Then the stable single TE01 vector beam is achieved by the superposition of LPy 11a and LPx 11b in an all-PM architecture, its output power is 3.1W and mode purity of 91.2%. Due to the all-PM architecture, our configuration is free of adjusting polarization controller (PC) and reliable during long-term operation. This laser could be used as a high-power CVBs source for a wide range of applications towards scientific research and industrial field.

The effects of biomechanical factors on adjacent vertebral compression fractures after percutaneous kyphoplasty: a propensity score matching analysis.

Adjacent vertebral compression fracture (AVCF) is the primary factor affecting satisfaction after PKP surgery. In addition to osteoporosis, certain structural characteristics of the vertebral body itself also increase their risk. The purpose of this study was to explore the impact of biomechanical changes on AVCF after balancing other factors. INTRODUCTION: As a routine treatment of OVCF, the postoperative refracture of PKP is a serious problem. The aim of our study was to explore the impact of lumbar biomechanical changes on the risk of AVCF. A propensity score matching was performed to balance the interference of osteoporosis, which is the primary risk factor of AVCF. METHODS: A retrospective, single-center case-control study was performed. From September 2013 to March 2020, 1752 patients were enrolled, and AVCF was assessed in 80 of these patients. A propensity score matching (PSM) analysis was performed, and 5 potential confounding factors were matched (age, BMI, number of fractured vertebral bodies, fracture region, and HDL). The preoperative and postoperative radiological factors were measured in the matched cohort of 48 pairs. A conditional logistic regression analysis to adjust the comparative risks. RESULTS: The preoperative wedge angle and its postoperative recovery of the AVCF group were significantly higher than that of the non-AVCF group. The local kyphosis of the fractured vertebral body between the two groups was similar, but the recovery in the AVCF group was slightly higher than that in the non-AVCF group. The preoperative and postoperative relative anterior height (RAH) of the fractured vertebral body was familiar in two groups, so was the recovery of RAH. The preoperative spino-sacral angle (SSA) was significantly higher in the AVCF group than in the non-AVCF group. The preoperative wedge angle was identified as the only significant risk factor for AVCF in the multivariate analysis. CONCLUSION: In conclusion, a larger preoperative fracture vertebral wedge angle is a risk factor for AVCF. For such high-risk patients, surgeons should be cautious about surgical decisions. The postoperative active measures and tailored surveillance should be attached to great importance as well.

Inhibition of RhoA/MRTF-A signaling alleviates nucleus pulposus fibrosis induced by mechanical stress overload.

PURPOSE/AIM: : Intervertebral disc degeneration (IDD) is the leading cause of lower back pain, and clinically useful drugs for IDD are unavailable. Mechanical stress overload-induced fibrosis plays a critical role in IDD. RhoA/MRTF-A signaling is known to regulate tissue fibrosis; however, the effect of RhoA/MRTF-A on the development of IDD is unclear. MATERIALS AND METHODS: : The expression of aggrecan, collagen I, collagen II, MMP-12, CTGF, and MRTF-A in nucleus pulposus (NP) samples from IDD patients and controls was detected by immunohistochemical staining. Primary nucleus pulposus cells (NPCs) were isolated and cultured to establish an overload strain model treated with or without CCG-1423. The protein levels of RhoA, ROCK2, MRTF-A, CTGF, and MMP-12 as well as fibrosis-associated proteins were detected by western blotting and immunofluorescence. RESULTS: : Collagen I, MMP-12, and CTGF were significantly upregulated, and aggrecan and collagen II were significantly downregulated in the IDD samples. The cellular localization of MRTF-A was associated with intervertebral disc (IVD) degeneration. Overloaded strain enhanced the nuclear translocation of MRTF-A and changed the NPC morphology from spindle-shaped to long strips. Additional experiments showed that RhoA, ROCK2, MRTF-A, SRF, MMP-12, and CTGF were upregulated; however, aggrecan and collagen II were downregulated in NPCs under overload strain. CCG-1423, a RhoA/MRTF-A pathway inhibitor, reversed strain-induced fibrosis. CONCLUSION: : Mechanical stress activates RhoA/MRTF-A signaling to promote extracellular matrix (ECM) degeneration in the NP, which is associated with the development of IDD. Our findings suggest that the RhoA/MRTF-A inhibitor CCG-1423 can alleviate NPC degeneration caused by overload stress and has potential as a therapeutic agent for IDD.

Application of electromagnetic navigation in endoscopic transforaminal lumbar interbody fusion: a cohort study.

STUDY DESIGN: Clinical retrospective cohort study. OBJECTIVES: To explore the application of the electromagnetic navigation system in Endo-TLIF. MATERIALS AND METHODS: From May 2019 to March 2020, 76 patients with single-segment lumbar spondylolisthesis treated by electromagnetic navigation-assisted Endo-TLIF (NE group) and conventional Endo-TLIF (CE group) were enrolled in the study. Time of pedicle screw implantation, entire operation time, the number of intraoperative X-ray fluoroscopy exposures, total blood loss, incision length, ambulation time, accuracy of pedicle screws, complications, visual analog scale for back and leg pain, Oswestry Disability Index, Japanese Orthopedic Association score and postoperative fusion rates were recorded, respectively. RESULTS: There were no significant differences in preoperative demographics between the NE and CE groups (P > 0.05). The mean number of intraoperative X-ray fluoroscopy exposures, guidewires insertion, entire operation time, total blood loss and adjustment rate of screws in the NE group were significantly less compared with the CE group (P < 0.05, respectively). There were no significant differences in clinical parameters between the two groups at different time points in the follow-up period (P > 0.05). There was no statistical difference in fusion rates between the two groups. In addition, one case of cage subsidence was observed after surgery in the CE group. CONCLUSION: Electromagnetic navigation systems could be applied throughout the entire surgical course and ameliorate the shortcomings of the conventional Endo-TLIF technique to reduce radiation exposure, improve accuracy, avoid repetitive operations and shorten surgery time and the required learning curve of the procedure. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Comparison of electromagnetic and optical navigation assisted Endo-TLIF in the treatment of lumbar spondylolisthesis.

Uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion (Endo-TLIF) with percutaneous pedicle screw fixation is a promising, minimally invasive method for the treatment of lumbar spondylolisthesis. However, repeated radiation exposure from X-rays and the steep learning curve remain to be improved.

Sequential endoscopic and robot-assisted surgical solutions for a rare fungal spondylodiscitis, secondary lumbar spinal stenosis, and subsequent discal pseudocyst causing acute cauda equina syndrome: a case report.

BACKGROUND: Fungal spondylodiscitis is a rare infectious disease. The secondary lumbar spinal stenosis and postoperative discal pseudocyst were even rarer. The surgical interventions were disputed, yet endoscopic and robot-assisted techniques may be helpful under different circumstances. CASE PRESENTATION: A 62-year-old female was diagnosed as infectious spondylodiscitis at the L4/5 level and a posterolateral endoscopic debridement was performed after invalid conservative therapy. Causative organism culture revealed a rare fungus, Candida tropicalis. A secondary spinal stenosis with refractory radiculopathy occurred almost 3 years after the first surgery and a successful endoscopic surgery was implemented aiming to decompress the nerve in a minimally invasive way. However, 2 months later, the patient manifested severe acute cauda equina syndrome and radiological examinations suggested a rare postoperative discal pseudocyst. A laminectomy followed by a pseudocystectomy was applied to achieve thorough decompression. An innovative double trajectory system (simultaneous traditional pedicle screw and cortical bone trajectory screw) accompanied by posterolateral fusion was designed and executed by the professional robot-assisted system. CONCLUSION: Endoscopic and robot-assisted techniques may provide alternative solutions for fungal spondylodiscitis and accompanied sequelae.

Relationship between hinge fracture and postoperative axial symptoms after cervical laminoplasty.

OBJECTIVE: To identify the clinical characteristics of fractured hinges after open-door cervical laminoplasty for cervical canal stenosis and explore the relationship between hinge fractures and axial symptoms. METHODS: This was a retrospective study of patients with cervical myelopathy who underwent open-door laminoplasty between November 2014 and November 2016 at the Affiliated Hospital of Qingdao University. Cervical CT scans were performed after surgery and the Takeuchi criteria were applied to evaluate the postoperative axial symptoms. RESULTS: Of 223 opened laminae in 67 patients, 67 laminae (30.0%) in 30 patients (44.8%) showed fracture. The frequency of hinge fractures was higher at C6 (53.7%). Forty-nine fractured laminae (73.13%) were non-displaced and 18 were displaced. At 3 months, 33 fractured laminae (49.3%) showed bony union on CT, and union rates were 86.6% and 91.0% at 6 and 12 months, respectively, indicating that the union rate was lower for displaced fractures than for non-displaced fractures. Among the 67 patients, 14 had axial symptoms: three of 37 (8.1%) patients without hinge fractures and 11 of 30 (36.7%) patients with hinge fractures. One year later, the hinge fractures were healed in 24/30 patients. Among the six unhealed patients, five still suffered from axial symptoms. The frequency of axial symptoms was higher in the patients with three or more hinge fractures (66.7%) than in the patients with only one (16.7%) or two (46.7%) hinge fractures. CONCLUSIONS: Patients with hinge fractures may have an increased risk for axial symptoms after open-door cervical laminoplasty. The frequency of axial symptoms decreases with fracture healing.

The technical feasibility and preliminary results of minimally invasive endoscopic-TLIF based on electromagnetic navigation: a case series.

BACKGROUND: Uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion (Endo-TLIF) with percutaneous pedicle screw fixation is a promising, minimally invasive method for the treatment of lumbar spondylolisthesis. However, repeated radiation exposure from X-rays and the steep learning curve remain to be improved. METHODS: This retrospective study explored the effects of electromagnetic navigation on improving Endo-TLIF with percutaneous pedicle screw fixation. Clinical information from 42 patients who had received Endo-TLIF with percutaneous pedicle screw fixation from May 2019 to November 2020 was analyzed retrospectively. The procedures were assisted under electromagnetic navigation. The rate of adjustment for guide wires, frequency of X-ray exposure, operative time, accuracy of pedicle screw location, and clinical outcomes were recorded. RESULTS: The mean follow-up for 42 patients was 11.9 ± 3.1 months. The mean age of the patients was 56.1 ± 9.26 years, with a female/male ratio of 25:17. According to postoperative CT scans and 3D reconstructions, the excellent and good rate of pedicle screws was 96.4%. The rate of adjustment for guide wires under the assistance of electromagnetic navigation was 1.78%, and the frequency of X-ray exposure was 8.27 ± 1.83. The operative time was 167.25 ± 28.16 min, including the duration of guide wire insertion (14.63 ± 5.45 min) and duration of decompression and cage placement (75.43 ± 13.97 min). The duration of hospitalization after operation was 2.59 ± 1.16 days. The preoperative VAS score was 7.51 ± 1.91, and the preoperative ODI was 82.42 ± 8.7%. At the last follow-up, the VAS score was 2.09 ± 0.59, and the ODI was 11.09 ± 3.2%. There were statistically significant improvements in the VAS score and ODI in all patients at the follow-up (p < 0.05). CONCLUSIONS: Electromagnetic navigation can provide accurate positioning and guidance in real time, which improves the surgical efficiency of percutaneous pedicle screw placement and endoscopic decompression in Endo-TLIF with reduced radiation exposures.

Differential proteomic analysis of fetal and geriatric lumbar nucleus pulposus: immunoinflammation and age-related intervertebral disc degeneration.

BACKGROUND: Intervertebral disc degeneration (IVDD) is a major cause of low back pain. Although the mechanism of degeneration remains unclear, aging has been recognized as a key risk factor for IVDD. Most studies seeking to identify IVDD-associated molecular alterations in the context of human age-related IVDD have focused only on a limited number of proteins. Differential proteomic analysis is an ideal method for comprehensively screening altered protein profiles and identifying the potential pathways related to pathological processes such as disc degeneration. METHODS: In this study, tandem mass tag (TMT) labeling was combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for differential proteomic analysis of human fetal and geriatric lumbar disc nucleus pulposus (NP) tissue. Parallel reaction monitoring (PRM) and Western blotting (WB) techniques were used to identify target proteins. Bioinformatic analyses, including Gene Ontology (GO) annotation, domain annotation, pathway annotation, subcellular localization and functional enrichment analyses, were used to interpret the potential significance of the protein alterations in the mechanism of IVDD. Student's t-tests and two-tailed Fisher's exact tests were used for statistical analysis. RESULTS: Six hundred forty five proteins were significantly upregulated and 748 proteins were downregulated in the geriatric group compared with the fetal group. Twelve proteins were verified to have significant differences in abundance between geriatric and fetal NP tissue; most of these have not been previously identified as being associated with human IVDD. The potential significance of the differentially expressed proteins in age-related IVDD was analyzed from multiple perspectives, especially with regard to the association of the immunoinflammatory response with IVDD. CONCLUSIONS: Differential proteomic analysis was used as a comprehensive strategy for elucidating the protein alterations associated with age-related IVDD. The findings of this study will aid in the screening of new biomarkers and molecular targets for the diagnosis and therapy of IVDD. The results may also significantly enhance our understanding of the pathophysiological process and mechanism of age-related IVDD.

Thoracic psammomatous meningioma with osseous metaplasia: a controversial diagnosis of a case report and literature review.

BACKGROUND: Spinal psammomatous meningioma with calcification is commonly observed, but distinctive osseous differentiation rarely occurs. CASE PRESENTATION: Here, we described a 52-year-old female complaining of chronic back pain for 5 years. CT and MRI examinations revealed an intradural extramedullary mass at the T4 level. The tumor was meticulously excised en bloc. Under the microscope, the tumor was found to be composed of conspicuous calcified psammoma bodies with remarkable immature bone formation. A primary diagnosis of psammomatous meningioma was made based on the recent WHO classification of tumors of the CNS, whereas other pathologists focused on the osseous components and preferred metaplastic meningioma as the proper subtype. A literature review was conducted, and only five cases have been reported with the same histopathological condition. Experts finally reached a consensus based on the acknowledged notion of the preferential diagnosis of psammomatous meningioma, as well as the current evidence and popular opinion that ossification is generated from osteogenic differentiation of pluripotent cells rather than the accumulation of psammoma bodies. CONCLUSIONS: A final diagnosis of psammomatous meningioma with osseous metaplasia was made. The rigid and adherent features complicate total resection of the tumor and increase the risk of neurologic deficits.