Accuracy of mapping results of thoracolumbar vertebral fracture verified using finite element analysis.

OBJECTIVE: To verify the results of three-dimensional fracture mapping of T12-L2 compression fractures by the finite element method from a biomechanical point of view, and to provide clinical reference. METHODS: This study is a retrospective study. By collecting 150 patients' computerized tomography (CT) data with thoracolumbar compression fractures (T12-L2) with AO type A. Mimics was used for three-dimensional (3D) reconstruction, and 3-Matic was used to mark fracture lines in stereo images. After standardized treatment, all fracture lines were drawn in the same 3D image, and finally fracture lines and fracture map were drawn. Constructing a 3D finite element model of thoracolumbar segment to verify the fracture thermogram results from the perspective of biomechanics. RESULTS: From the fracture map, fracture lines were mainly distributed in the upper part of the vertebral body, the leading edge of the anterior column (AC), and the lateral margin of the middle column (MC). In the finite element analysis, the stress mainly was concentrated on the edge of the anterior and middle column of the vertebral body and the upper part of the vertebral body, and the stress gradually decreased from the upper endplate to the endplate, and the stress was the least in the posterior column (PC) of the vertebral body. CONCLUSION: The results of finite element analysis further confirm the accuracy of fracture mapping and explain the distribution characteristics of fracture lines. This will provide theoretical support for the selection of clinical fracture treatment, intraoperative implants, and for a standard fracture model.

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.

Endoscopic Revision Strategies and Outcomes for Recurrent L4/5 Disc Herniation After Percutaneous Endoscopic Transforaminal Discectomy.

Objective: We explore the endoscopic revision and surgical techniques for L4/5 recurrent disc herniation (rLDH) after percutaneous endoscopic transforaminal discectomy (PETD). Methods: A retrospective study was conducted. From January 2016 to September 2022, 96 patients who underwent percutaneous endoscopic lumbar discectomy for L4/5 rLDH after PETD were enrolled in the study. Based on the revision approach, the patients were divided into PETD group (57 cases) and percutaneous endoscopic interlaminar discectomy (PEID) group (39 cases). Visual Analogue Scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and modified MacNab standard were recorded to evaluate the clinical outcomes. Results: No significant differences were found in the demographic data and intraoperative blood loss between the two groups (P>0.05), but the time of operation and intraoperative X-ray fluoroscopy exposures in the PEID group were significantly less than that in the PETD group (P<0.05). The patients' postoperative clinical indexes gradually improved, and the VAS score, ODI index, and JOA score of the patients in both groups showed significant improvement compared with the preoperative period at the 1-week, 1-month, and 6-month postoperative follow-ups (P < 0.05). There was no serious complication observed during the follow-up. Conclusion: For recurrent LDH after PETD of L4/5 segments, percutaneous endoscopic revision can achieve satisfactory results. Among them, PEID has a shorter operative and fluoroscopy time and allows avoidance of the scar that forms after the initial surgery, so it can be considered preferred when both procedures can remove the disk well. However, for some specific types of herniation, a detailed surgical strategy is required.

Analysis of the Screw Accuracy and Postoperative Efficacy of Screw Placement in Single Position and Bipedal Position in Robot-Assisted Oblique Lumbar Interbody Fusion: Preliminary Results of Mazor X Stealth Usage.

OBJECTIVE: Traditional manual OLIF combined with pedicle screw implantation has many problems of manual percutaneous screw implantation, such as high difficulty of screw placement, many fluoroscopies, long operation time, and many adjustments, resulting in greater trauma. The robot can perform various types of screw placement in the lateral recumbent position, which allows OLIF combined with posterior screw placement surgery to be completed in a single position. To compare the screw accuracy and initial postoperative results of oblique anterior lumbar fusion with robot-assisted screw placement in the lateral position and screw placement in the prone position for the treatment of lumbar spondylolisthesis. METHODS: From May to June 2022, 45 patients with single-segment lumbar spondylolisthesis underwent Mazor X-assisted oblique lumbar fusion in one position and Renaissance-assisted surgery in two different positions, and screw accuracy was assessed on computed tomography scans according to a modified Gertzbein-Robbins classification. Patients were divided into a single position group and a bipedal position group (the lateral position for complete oblique lumbar fusion and then changed to the prone position for posterior screw placement), and the perioperative parameters, including operative time, number of fluoroscopies, and operative complications, were recorded separately. The results of the clinical indicators, such as the visual analog scale (VAS) for back and leg pain and the Oswestry Disability Index (ODI) score, were obtained. RESULTS: There were no significant differences in the patients' demographic data between the two groups. The single position group had a shorter operative time and fewer fluoroscopies than the bipedal position group; the single position group had a higher percentage of screw accuracy at the A level than the bipedal position group, but there was no statistically significant difference between the two groups at the acceptable level (A + B) (p > 0.05). The single-position group had better outcomes at the 1-week postoperative follow-up back pain VAS scores (p < 0.05). There was no statistically significant difference in the postoperative leg pain VAS scores or the ODI scores when compared to the control group. CONCLUSION: Robot-assisted lateral position oblique lumbar interbody fusion with pedicle screw placement has the same accuracy as prone positioning. Single position surgery can significantly shorten the operation time and reduce the fluoroscopy. There was no significant difference in the long-term efficacy between the two groups.

Comparison of Percutaneous Endoscopic Transforaminal and Interlaminar Approaches in Treating Adjacent Segment Disease Following Lumbar Decompression Surgery: A Clinical Retrospective Study.

BACKGROUND: Adjacent segment disease (ASD) is a common complication following posterior disc decompression and fusion surgery. Percutaneous endoscopic lumbar decompression surgery (PELD) has been used to treat ASD through either a transforaminal or interlaminar approach. However, to our limited knowledge there are no reports comparing the 2 approaches for treating ASD. OBJECTIVE: To evaluate clinical outcomes of PELD in treating ASD and comparing the surgical results and complications between the 2 approaches. This may be helpful for spinal surgeons when decision-making ASD treatment. STUDY DESIGN: A clinical retrospective study. SETTING: This study was conducted at the Department of Orthopedics of the Affiliated Hospital of Qingdao University. METHODS: From January 2015 through December 2019, a total of 68 patients with ASD who underwent PELD after lumbar posterior decompression with fusion surgery were included in this study. The patients were divided into a percutaneous endoscopic transforaminal decompression (PETD) group and a percutaneous endoscopic interlaminar decompression (PEID) group according to the approach used. The demographic characteristics, radiographic and clinical outcomes, and complications were recorded in both groups through a chart review. RESULTS: Of the 68 patients, 40 underwent PEID and 28 patients underwent PETD. Compared with their preoperative Visual Analog Scale (VAS) pain score and Oswestry Disability Index (ODI) score, all patients had significant postoperative improvement at 3 months, 6 months, one year and at the latest follow-up. There were no significant statistical differences in the VAS and ODI scores between PETD and PEID groups with a P value > 0.05. There was a significant statistical difference in the average fluoroscopy times between the PETD and PEID groups with a P value = 0.000. Revision surgery occurred in 8 patients: 6 patients who underwent PETD and 2 patients who underwent PEID. The revision rate showed a significant statistical difference between the 2 approaches with a P value = 0.039. LIMITATIONS: Firstly, the number of patients included in this study was small. More patients are needed in a further study. Secondly, the follow-up time was limited in this study. There is still no conclusion about whether the primary decompression with instruments will increase the reoperation rate after a PELD, and a longer follow-up is needed in the future. Thirdly, this study was a clinical retrospective study. Randomized or controlled trials are needed in the future in order to achieve a higher level of evidence. Fourthly, there were debates about PELD approach choices for ASDs, which may affect the comparison results between PETD and PEID. In our study, the approaches were mainly determined by the level and types of disc herniation, and the surgeons' preference. More patients with an ASD with different levels and types of disc herniation and surgical approaches are needed in the future to eliminate these biases. CONCLUSION: Percutaneous endoscopic lumbar decompression surgery is a feasible option for ASD following lumbar decompression surgery with instruments. Compared with PETD, PEID seems to be a better approach to treat symptomatic ASDs.

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.

The Cortical Bone Trajectory Screw Technique Assisted by the Mazor Renaissance Robotic System as a Salvage Strategy for Failed Lumbar Spine Surgery: Technical Note and Case Series.

Purpose: The objective of this study was to describe the Mazor Renaissance robotic system-assisted CBT (cortical bone trajectory) screw technique as a salvage strategy for failed lumbar spine surgery. Patients and Methods: Between January 2018 and June 2022, 7 patients underwent salvage surgery with the CBT screw fixation technique assisted by the Mazor Renaissance robot system in our institution. Intraoperative observations were recorded for blood loss, duration of operation, and fluoroscopy time. Complications related to CBT screws were also recorded. The accuracy of CBT screws was recorded in accordance with the modified Gertzbein-Robbins classification. The JOA (Japanese Orthopedic Association) score for low back pain was used to evaluate surgical outcomes. Results: A total of 26 CBT screws were placed in 7 patients, including 4 females and 3 males. Three patients underwent ASD (adjacent segment disease) and four patients underwent lumbar union failure with loose or compromised PSs (pedicle screws). The mean operation time was 129.29 ± 32.97 minutes, the mean blood loss was 180 ± 52.60 mL, and the mean intraoperative fluoroscopy time was 14.29 ± 3.15 s. All screws were clinically acceptable according to the Gertzbein-Robbins classification. There were no complications related to CBT screws in any of the cases. The JOA scores for low back pain of all patients were significantly improved at the final follow-up. Conclusion: The CBT screw fixation technique supplemented the traditional PS fixation technique, which can be performed as a salvage strategy for failed lumbar spine surgery and achieved good clinical results. The spinal robot was very helpful in evaluating pedicle size and determining CBT screw direction, especially in a previously instrumented lumbar pedicle.

Surgical Strategy and Outcomes of Full Endoscopic Lumbar Discectomy for Recurrent Lumbar Disk Herniation Following a Previous Full Endoscopic Lumbar Discectomy.

OBJECTIVE: Recurrent lumbar disc herniation (RLDH) cannot be prevented after full endoscopic lumbar discectomy (FELD), and the optimal surgical treatment for RLDH after FELD remains controversial. The aim of the study was to suggest a surgical strategy for FELD to treat RLDH following a previous FELD and to present surgical outcomes. METHODS: Between February 2015 and March 2022, 68 patients with RLDH were surgically treated with FELD retrospectively. An original approach was suggested for the treatment of early recurrence (24 h-2 weeks). The full endoscopic transforaminal technique (FETD) was considered for patients requiring local anesthesia, and in RLDH with FETD indications or FEID technological difficulties. The full endoscopic interlaminar technique (FEID) was chosen in RLDH with FEID indications. Both FEID and FETD were suitable if no FEID or FETD technological difficulties existed. Clinical efficacy was evaluated using the visual analog scale (VAS) score, Oswestry disability index (ODI), and modified MacNab criteria. Postoperative follow-up data at 24 h, 3 months, and final-follow-up were recorded. Operation time and clinical outcomes were assessed with t test. p-value < 0.05 was considered statistically significant. RESULTS: All 68 patients had an average follow-up time of 23.8 months (range, 6-76 months). In the 13 cases of early recurrence, the operation time (32.30 ± 9.67 vs. 58.00 ± 6.16 min) in the original surgical approach group was shorter than that in the changing surgical approach group (p < 0.05). In the 28 cases of L4/5 FETD recurrence (>2 weeks), the operation time (66.17 ± 12.18 vs. 53.60 ± 5.45 min) in the FETD group was more than that in the FEID group (p < 0.05). In the 22 cases of L5S1 recurrence (>2 weeks), the operation time (55.75 ± 8.79 vs. 79.33 ± 6.65 min) in the FEID group was shorter than in the FETD group (p < 0.05). The postoperative VAS and ODI scores at 24 h, 3 months, and final-follow up were all significantly improved, compared with their preoperative counterparts (p < 0.05). Based on the modified MacNab criteria, 88.23% of patients showed excellent or good results. Re-recurrence occurred in three patients at 3 months. No surgical complications were observed in any of the 68 cases. CONCLUSION: FELD is a safe and effective treatment option for RLDH with previous FELD. For early recurrence, the original approach was suggested. Both FEID and FETD were effective and safe for recurrence (>2 weeks), but FEID seemed more efficient for L4/5 RLDH after previous FETD and for L5S1 RLDH.

Irreversible Electroporation Combined With Dendritic Cell-based Vaccines for the Treatment of Osteosarcoma.

Osteosarcoma is the most common primary bone malignancy, and surgical resection combined with neoadjuvant chemotherapy is the gold-standard treatment for affected patients. Although the overall survival rates for patients with osteosarcoma currently range from 60% to 70%, outcomes remain disappointing for patients with recurrent, metastatic, or unresectable disease. Irreversible electroporation (IRE) is a novel ablation technique with the potential to elicit an immune response in solid tumors. Dendritic cell (DC)-based tumor vaccines have shown promising therapeutic efficacy in preclinical studies focused on osteosarcoma; however, only limited therapeutic efficacy has been observed in clinical trials. Thus, there is considerable potential therapeutic value in developing combination osteosarcoma treatments that involve IRE and DC-based tumor vaccines. In this review, we discuss recent advances in preclinical and clinical DC-based immunotherapies, as well as potential combinations of DC-based vaccines and IRE, that may improve therapeutic outcomes for patients with osteosarcoma.

Severe Symptomatic Epidural Hematoma Following Percutaneous Endoscopic Unilateral Laminectomy for Bilateral Decompression (Endo-ULBD)-Series Report and Management Strategies.

OBJECTIVES: Severe symptomatic epidural hematoma (SSEH) is one of the most severe complications following percutaneous endoscopic unilateral laminectomy for bilateral decompression (Endo-ULBD). Considering that this technique has been performed for a short time, no detailed reports have been recently published. Thus, it is critical to gain a better understanding of SSEH occurring in its postoperative period with regard to its incidence, possible causes, outcome, etc., in order to identify relevant management strategies. METHODS: Patients with spinal stenosis who had undergone Endo-ULBD in our department from May 2019 to May 2022 were retrospectively analyzed. Of which, patients with postoperative epidural hematoma were followed-up. The preoperative and postoperative physical conditions of each patient were recorded, and the information related to hematoma removal surgery was recorded in detail. Clinical outcomes were assessed using the visual analogue scale (VAS) and Oswestry disability index (ODI), and the results were classified into "excellent," "good," "fair," or "poor" based on the modified MacNab criteria. The incidence of hematoma with different factors was calculated, and a bar graph was used to compare the difference of the indexes related to hematoma removal between cases, and a line graph was used to reflect the trend of the outcome of each patient within 6 months to evaluate the effect of the treatment. RESULTS: A total of 461 patients with spinal stenosis who underwent Endo-ULBD were enrolled in the study. SSEH occurred in four cases, with an incidence rate of 0.87% (4/461). All these four patients underwent decompression of multiple segments, and three of them had a history of hypertension comorbid with diabetes. Notably, one patient had a past history of hypertension and coronary artery disease and was on postoperative low molecular heparin due to lower extremity venous thrombosis. According to the conditions of the four patients, three types of treatment were used. And with timely treatment, all patients recovered well. CONCLUSION: Despite being a minimally invasive technique, postoperative epidural hematoma remains a severe complication of Endo-ULBD. Therefore, during percutaneous endoscopic surgery, it is essential to enhance the comprehensive perioperative management of patients with Endo-ULBD. Signs related to postoperative hematoma must be recognized and promptly managed. If necessary, satisfactory results can be achieved by using percutaneous endoscopy along the original surgical channel to remove the hematoma.

Application of the oblique lateral interbody fusion technique in salvage surgery: technical note and case series.

Objective: The oblique lateral interbody fusion (OLIF) technique is a promising interbody fusion technique. This study summarizes the technical aspects of OLIF as a salvage surgery and the preliminary outcomes of a series of cases. Patients and methods: A retrospective review of patients with leg or back pain induced by pseudoarthrosis or adjacent segment disease after posterior lumbar interbody fusion/transforaminal lumbar interbody fusion was done. These patients underwent salvage OLIF surgeries in our institution from January 2021 to March 2022. Variables such as the demographic, clinical, surgical, and radiological characteristics of the enrolled patients were recorded and analyzed. Results: Eight patients (five females and three males; mean age 69.1 ± 5.7 years, range 63-80 years) were enrolled in this study. The mean operative time was 286.25 min (range: 230-440 min), and the estimated blood loss was 90 ml (range: 50-150 ml). Only one of the eight patients experienced a complication of lower limb motor weakness, which disappeared within 5 days after surgery. The latest data showed that the mean intervertebral space height increased from 8.36 mm preoperatively to 12.70 mm and the mean segmentary lordosis increased from 8.92° preoperatively to 15.05°. Bone fusion was achieved in all but one patient, who was followed up for only 3 months. The JOA scores Japanese Orthopaedic Association (JOA) Scores for low back pain of all patients significantly improved at the final follow-up. Conclusion: OLIF provides a safe and effective salvage strategy for patients with failed posterior intervertebral fusion surgery. Patients effectively recovered intervertebral and foraminal height with no additional posterior direct decompression.

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.

A rare gas-containing lumbar synovial cyst treated by percutaneous transforaminal endoscopic cystectomy: A case report and literature review.

Spinal synovial cysts are rare entities for which standard surgical strategies are inconsistent. Here, we present an uncommon intraspinal gas-containing synovial cyst treated by percutaneous transforaminal endoscopic cystectomy. A 52-year-old man presented with radicular pain and intermittent claudication that had persisted for one month. Computed tomography revealed an intraspinal cystic lesion anteromedial to the left L4-L5 articular joint and the center of the lesion manifested gas contents. A transforaminal endoscopic procedure was performed and confirmed as a safe and minimally invasive technique for gas-containing lumbar synovial cysts. It provides a valuable substitution and supplementation to open surgery.

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.

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.

Surgical Precision and Efficiency of a Novel Electromagnetic System Compared to a Robot-Assisted System in Percutaneous Pedicle Screw Placement of Endo-LIF.

STUDY DESIGN: Retrospective database study. OBJECTIVES: To compare the accuracy and safety of 2 types of a computer-assisted navigation system for percutaneous pedicle screw placement during endoscopic lumbar interbody fusion. METHODS: From May 2019 to January 2020, data of 56 patients who underwent Endo-LIF with a robot-assisted system and with an electromagnetic navigation system were compared. The pedicles in all patients were subjected to postoperative CT scan to assess screw correction by measuring the perpendicular distance between the pedicle cortical wall and the screw surface. The registration and matching time, guide-wire insertion time, the entire surgery time, and X-ray exposure time were recorded. RESULTS: In the robot-assisted group, 25 cases with 100 percutaneous pedicle screws were included, and the excellent and good rate was 95%. In the electromagnetic navigation group, 31 cases with 124 screws were included, and the excellent rate was 97.6%. There was no statistical difference between the two groups (P > 0.05). The registration time and the total time for the surgery also showed no statistical differences (P > 0.05). The main difference between the two groups was the guide-wire insertion time and the X-ray exposure time (P < 0.05). CONCLUSIONS: Both electromagnetic navigation and robot-assisted are safe and efficient for percutaneous pedicle screw placement. Electromagnetic navigation system has obvious advantages over robot-assisted in terms of faster guide-wire placement and less X-ray exposure. Robot-assisted for percutaneous pedicle screw placement offers a preoperative planning system and a stable registration system, with obvious drawbacks of a strict training curve.

Combining Mendelian Randomization Analysis and 3D-QSAR to Investigate the Effectiveness of a New Series of Hydroxyquinolines in Osteoarthritis.

BACKGROUND: Osteoarthritis (OA) represents a persistent degenerative joint ailment. As OA advances, profound joint pain coupled with diminished joint function inflicts substantial physical distress and psychological strain on patients. Presently, pharmacological solutions for arthritis remain limited, primarily encompassing analgesics and joint replacement surgical procedures. Hence, non-operative strategies to mitigate osteoarthritis progression have captured significant attention in orthopedic research. OBJECTIVE: This study aims to discern a definitive causal linkage between ADAMTS-4/5 and osteoarthritis through Mendelian randomization analysis. Moreover, it seeks to anticipate the therapeutic efficacy of a suite of emergent hydroxyquinolines for osteoarthritis using the Quantitative Structure-Activity Relationship (QSAR) methodology. METHODS: Within this study, genetic variants specific to knee osteoarthritis were procured as exposure variables from a genome-wide association study (GWAS). Genetic variant data for ADAMTS-4/5 served as the endpoint to evaluate the causal nexus employing univariate Mendelian randomization. This analysis underpins the hypothesis that ADAMTS-4/5 presents a promising therapeutic target for osteoarthritis management. The suppressive properties of novel hydroxyquinolines against ADAMTS-4/5 were subsequently examined through conformational analyses, underscoring the potential of these compounds as therapeutic candidates for osteoarthritis. RESULTS: IVW outcomes from the Mendelian randomization revealed a significant association of KOA (OR: 1.1675, 95% CI: 1.0003-1.3627, P = 0.0495) with ADAMTS-5. However, KOA (OR: 1.0801, 95% CI: 0.9256-1.2604, P = 0.3278) displayed no evident connection with ADAMTS-4. Notably, the instrumental variables manifested neither heterogeneity nor horizontal pleiotropy. In this research endeavor, 16 pharmacological models were formulated via the CoMSIA method within 3D conformational relationship evaluations. A synergistic interplay of hydrophobic, spatial, and hydrogen-bonded receptor domains emerged as the most predictively potent. The cross-validation coefficient q2 for the optimum model stood at 0.716, with a principal component score of 5, a regression coefficient r2 of 0.971, a standard estimation error of 0.351, and an f-value of 156.951. Such metrics intimate the commendable predictive prowess of our devised CoMSIA models. CONCLUSION: The research unearthed a robust causal interrelation between ADAMTS-5 and osteoarthritis via Mendelian randomization. Furthermore, a credible drug model targeting ADAMTS-5 was constructed. Collectively, these findings illuminate a path forward in the pursuit of target-specific drugs for osteoarthritis management in subsequent investigations.

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.

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.

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.