Factors associated with peroral endoscopic myotomy for achalasia outcomes: systematic review and meta-analysis.

BACKGROUND: Peroral endoscopic myotomy (POEM) is an emerging effective treatment for achalasia. However, a significant proportion of patients do not respond well to the treatment. After over a decade of clinical practice, potential risk factors associated with POEM failure have been identified. This meta-analysis aimed to summarize the evidence of risk factors for POEM failure. METHODS: A systematic literature search was conducted on PubMed, Embase, Web of Science, and Cochrane Library from inception to June 10th, 2022. We included English studies that reported POEM outcomes in achalasia patients and identified risk factors for POEM failure. Relevant information was extracted and analyzed using fixed- or randomized-effect models to pool the effect size. RESULTS: A total of 27 studies comprising 9371 patients with achalasia were included in this review. The pooled failure rate was 8% (90% CI 7%-10%). We identified sigmoid esophagus (OR 1.90, 95% CI 1.45-2.47), type I achalasia (OR 1.30, 95% CI 1.04-1.63), and type III achalasia (OR 1.26, 95% CI 0.89-1.78) were associated with a worse clinical response. Conversely, type II achalasia was associated with a better response (OR 0.59, 95% CI 0.47-0.75). Prior treatment with Heller myotomy (OR 5.75, 95% CI 3.97-8.34) and prior balloon dilation (OR 1.18, 95% CI 1.07-1.29) were also associated with a higher risk of clinical failure. CONCLUSION: Our meta-analysis results demonstrated that sigmoid esophagus, manometric achalasia subtype, and prior treatment were associated with POEM failure. This information could be used to guide treatment decisions and improve the success rate of POEM in achalasia patients.

Comparison of predictive performance for cage subsidence between CT-based Hounsfield units and MRI-based vertebral bone quality score following oblique lumbar interbody fusion.

OBJECTIVE: To compare the predictive performance between CT-based Hounsfield units (HU) and MRI-based vertebral bone quality (VBQ) for cage subsidence (CS) following oblique lumbar interbody fusion combined with anterolateral single-rod screw fixation (OLIF-AF). METHODS: A retrospective study was performed on consecutive patients who underwent OLIF-AF at our institution from 2018 to 2020. CS was determined by CT according to the change in the midpoint intervertebral space height. The VBQ score and HU value were measured from preoperative MRI and CT, respectively. Then, we evaluated the predictive performance of those two parameters by comparing the receiver operating characteristic (ROC) curves. RESULTS: The mean global and segmental VBQ scores were significantly higher in the CS group, and the mean global and segmental HU values were significantly lower in the CS group. The area under the curve (AUC) of CS prediction was higher in the operative segments' VBQ score and HU value than the measurement in the global lumbar spine. Finally, the combined segmental VBQ score and segmental HU value demonstrated the highest AUC. CONCLUSION: Both MRI-based VBQ score and CT-based HU value can achieve accurate CS prediction. Moreover, the combination of those two measurements indicated the best predictive performance. CLINICAL RELEVANCE STATEMENT: Both MRI-based VBQ score and CT-based HU value can be used for cage subsidence prediction, in order to take preventive measures early enough. KEY POINTS: • Osteoporosis is a risk factor for CS, both MRI-based VBQ score and CT-based HU value are important predictors during vertebral bone quality evaluation. • The VBQ score and HU value measured in the operative segments are better predictors of CS than the measurement in the global lumbar spine. • Combined segmental VBQ score and segmental HU value achieved the best predictive performance for CS.

Spontaneous facet joint fusion in patients following oblique lateral lumbar interbody fusion combined with lateral single screw-rod fixation: prevalence, characteristics and significance.

PURPOSE: To explore the characteristics of spontaneous facet joint fusion (SFJF) in patients after oblique lateral lumbar interbody fusion combined with lateral single screw-rod fixation (OLIF-LSRF). METHODS: We randomly selected 300 patients from 723 patients treated with OLIF-LSRF into a cross-sectional study based on the pilot study results. A novel fusion classification system was designed to evaluate the fusion status of the facet joints at three time points. Ultimately, the prevalence, characteristics, and significance of SFJF were analyzed. RESULTS: A total of 265 (333 levels) qualified cases were included in our study. The novel classification for SFJF has excellent reliability (kappa > 0.75). The rate of SFJF was 15.20% (45/296 levels) at 3 months postoperatively, 31.34% (89/284 levels) at 6 months postoperatively, and 33.63% (112/333 levels) at the last follow-up. The circumferential fusion rate was 31.53% (105/333 levels) at the last follow-up. The location of SFJF was mostly on the right facet joint (P < 0.001), and the rate of SFJF increased significantly from 3 to 6 months after the operation (P < 0.001). The average age of patients with SFJF was older than that of patients without SFJF (P < 0.001). There was no significant difference in Visual Analog Scale or Oswestry Disability Index scores between patients with and without SFJF. CONCLUSION: In the OLIF-LSRF procedure, SFJF occurs mostly at 3-6 months postoperatively, especially in elderly patients and at the right facet joint. OLIF-LSRF has the potential for circumferential fusion.

Clinical and radiological evaluation of cage subsidence following oblique lumbar interbody fusion combined with anterolateral fixation.

BACKGROUND: Cage subsidence (CS) was previously reported as one of the most common complications following oblique lumbar interbody fusion (OLIF). We aimed to assess the impacts of CS on surgical results following OLIF combined with anterolateral fixation, and determine its radiological characteristics as well as related risk factors. METHODS: Two hundred and forty-two patients who underwent OLIF at L4-5 and with a minimum 12 months follow-up were reviewed. Patients were divided into three groups according to the extent of disk height (DH) decrease during follow-up: no CS (DH decrease ≤ 2 mm), mild CS (2 mm < DH decrease ≤ 4 mm) and severe CS (DH decrease > 4 mm). The clinical and radiological results were compared between groups to evaluate radiological features, clinical effects and risk factors of CS. RESULTS: CS was identified in 79 (32.6%) patients, including 48 (19.8%) with mild CS and 31 (11.8%) with severe CS. CS was mainly identified within 1 month postoperatively, it did not progress after 3 months postoperatively, and more noted in the caudal endplate (44, 55.7%). In terms of clinical results, patients in the mild CS group were significantly worse than those in the no CS group, and patients in the severe CS group were significantly worse than those in the mild CS group. There was no significant difference in fusion rate between no CS (92.6%, 151/163) and mild CS (83.3%, 40/48) groups. However, significant lower fusion rate was observed in severe CS group (64.5%, 20/31) compared to no CS group. CS related risk factors included osteoporosis (OR = 5.976), DH overdistraction (OR = 1.175), flat disk space (OR = 3.309) and endplate injury (OR = 6.135). CONCLUSION: CS following OLIF was an early postoperative complication. Higher magnitudes of CS were associated with worse clinical improvements and lower intervertebral fusion. Osteoporosis and endplate injury were significant risk factors for CS. Additionally, flat disk space and DH over-distraction were also correlated with an increased probability of CS.

Influence of coronal-morphology of endplate and intervertebral space to cage subsidence and fusion following oblique lumbar interbody fusion.

BACKGROUND: Endplate morphology is considered to be one of the influencing factors of cage subsidence after lumbar interbody fusion (LIF). Previous radiographic evaluations on the endplate mostly used sagittal X-ray or MRI. However, there are few studies on the CT evaluation of the endplate and intervertebral space (IVS), especially the evaluation of coronal morphology and its influence on subsidence and fusion after LIF. We aimed to measure and classify the shapes of the endplate and IVS using coronal CT imaging and evaluate the radiographic and clinical outcomes of different shapes of the endplate/IVS following oblique lateral lumbar interbody fusion (OLIF). METHODS: A total of 137 patients (average age 59.1 years, including 75 males and 62 females) who underwent L4-5 OLIF combined with anterolateral fixation from June 2018 to June 2020 were included. The endplate concavity depth (ECD) was measured on the preoperative coronal CT image. According to ECD, the endplate was classified as flat (< 2 mm), shallow (2-4 mm), or deep (> 4 mm). The L4-5 IVS was further classified according to endplate type. The disc height (DH), DH changes, subsidence rate, fusion rate, and Oswestry Disability Index (ODI) in different endplate/IVS shapes were evaluated during 1-year follow up. RESULTS: The ECD of L4 inferior endplate (IEP) was significantly deeper than that of L5 superior endplate (SEP) (4.2 ± 1.1 vs 1.6 ± 0.8, P < 0.01). Four types of L4-5 IVS were identified: shallow-shallow (16, 11.7%), shallow-flat (45, 32.9%), deep-shallow (32, 23.4%), and deep-flat (44, 32.1%). A total of 45 (32.9%) cases of cage subsidence were observed. Only one (6.3%) subsidence event occurred in the shallow-shallow group, which was significantly lower than in the other three groups (19 shallow-flat, 6 deep-shallow, and 19 deep-flat) (P < 0.05). Meanwhile, the shallow-shallow group had the highest fusion rate (15, 93.8%) and the highest rate of reach minimal clinically important difference (MCID) ODI among the four types. For a single endplate, the shape of L4 IEP is the main influencing factor of the final interbody fusion rate, and the shallow shape L4 IEP facilitates fusion ( OR = 2.85, p = 0.03). On the other hand, the flat shape L5 SEP was the main risk factor to cage subsidence (OR = 4.36, p < 0.01). CONCLUSION: The L4-5 IVS is asymmetrical on coronal CT view and tends to be fornix-above and flat-down. The shallow-shallow IVS has the lowest subsidence rate and best fusion result, which is possibly because it has a relatively good degree in matching either the upper or lower interface of the cage and endplates. These findings provide a basis for the further improvements in the design of OLIF cages.

Stepwise reduction of bone mineral density increases the risk of cage subsidence in oblique lumbar interbody fusion patients biomechanically: an in-silico study.

BACKGROUND: Cage subsidence causes poor prognoses in patients treated by oblique lumbar interbody fusion (OLIF). Deterioration of the biomechanical environment initially triggers cage subsidence, and patients with low bone mineral density (BMD) suffer a higher risk of cage subsidence. However, whether low BMD increases the risk of cage subsidence by deteriorating the local biomechanical environment has not been clearly identified. METHODS: OLIF without additional fixation (stand-alone, S-A) and with different additional fixation devices (AFDs), including anterolateral single rod screws (ALSRs) and bilateral pedicle screws (BPSs) fixation, was simulated in the L4-L5 segment of a well-validated finite element model. The biomechanical effects of different BMDs were investigated by adjusting the material properties of bony structures. Biomechanical indicators related to cage subsidence were computed and recorded under different directional moments. RESULTS: Overall, low BMD triggers stress concentration in surgical segment, the highest equivalent stress can be observed in osteoporosis models under most loading conditions. Compared with the flexion-extension loading condition, this variation tendency was more pronounced under bending and rotation loading conditions. In addition, AFDs obviously reduced the stress concentration on both bony endplates and the OLIF cage, and the maximum stress on ALSRs was evidently higher than that on BPSs under almost all loading conditions. CONCLUSIONS: Stepwise reduction of BMD increases the risk of a poor local biomechanical environment in OLIF patients, and regular anti-osteoporosis therapy should be considered an effective method to biomechanically optimize the prognosis of OLIF patients.

Analysis of radiological parameters associated with decreased fractional anisotropy values on diffusion tensor imaging in patients with lumbar spinal stenosis.

PURPOSE: Previous studies have indicated that decreased fractional anisotropy (FA) values on diffusion tensor imaging (DTI) are well correlated with the symptoms of nerve root compression. The aim of our study is to determine primary radiological parameters associated with decreased FA values in patients with lumbar spinal stenosis involving single L5 nerve root. METHODS: Patients confirmed with single L5 nerve root compression by transforaminal nerve root blocks were included in this study. FA values of L5 nerve roots on both symptomatic and asymptomatic side were obtained. Conventional radiological parameters, such as disc height, degenerative scoliosis, dural sac cross-sectional area (DSCSA), foraminal height (FH), hypertrophic facet joint degeneration (HFJD), sagittal rotation (SR), sedimentation sign, sagittal translation and traction spur were measured. Correlation and regression analyses were performed between the radiological parameters and FA values of the symptomatic L5 nerve roots. A predictive regression equation was established. RESULTS: Twenty-one patients were included in this study. FA values were significantly lower at the symptomatic side comparing to the asymptomatic side (0.263 ± 0.069 vs. 0.334 ± 0.080, P = 0.038). DSCSA, FH, HFJD, and SR were significantly correlated with the decreased FA values, with r = 0.518, 0.443, 0.472 and - 0.910, respectively (P < 0.05). DSCSA and SR were found to be the primary radiological parameters related to the decreased FA values, and the regression equation is FA = - 0.012 × SR + 0.002 × DSCSA. CONCLUSIONS: DSCSA and SR were primary contributors to decreased FA values in LSS patients involving single L5 nerve root, indicating that central canal decompression and segmental stability should be the first considerations in preoperative planning of these patients. These slides can be retrieved under Electronic Supplementary Material.

Negative pressure pulmonary edema after percutaneous endoscopic interlaminar lumbar discectomy-a case report.

BACKGROUND: Negative pressure pulmonary edema (NPPE) is a rare complication that is more prevalent in young patients. NPPE usually results from acute upper airway obstruction, which is most commonly caused by laryngospasm during extubation. NPPE is characterized by the sudden onset of coughing, hemoptysis, tachycardia, tachypnea, and hypoxia, and is dramatically improved with supportive care, which prevents severe sequelae. To our knowledge, there is no report of a patient developing NPPE after percutaneous endoscopic interlaminar lumbar discectomy. CASE PRESENTATION: Herein, we report the case of a 22-year-old amateur basketball player with L5/S1 disc herniation who developed NPPE during extubation after general anesthesia for a minimally invasive spinal surgery (percutaneous endoscopic interlaminar lumbar discectomy). The NPPE was treated by maintaining the airway patency, applying positive-pressure ventilation, administering dexamethasone and antibiotics, and limiting the volume of fluid infused. The patient had an uneventful postoperative course, and was discharged to his home on postoperative day 3. CONCLUSIONS: Although NPPE is an infrequent complication, especially in patients undergoing percutaneous endoscopic interlaminar lumbar discectomy, this case report highlights the importance of early diagnosis and prompt treatment of NPPE to prevent the development of potentially fatal complications.

Percutaneous endoscopic interlaminar discectomy for pediatric lumbar disc herniation.

PURPOSE: Percutaneous endoscopic interlaminar discectomy (PEID) is a widely used minimally invasive procedure which shows satisfying outcomes in the adult population. However, pediatric lumbar disc herniations (PLDH) occur in growing spines and are less related to degeneration, which makes them different from the adult disc herniations. This study evaluates the clinical outcomes of PEID in treating PLDH. METHODS: A prospect study was done in the period from June 2010 to December 2012, which included 29 consecutive pediatric patients with a mean age of 16.4 years (range, 13 to 18 years) who underwent PEID for single level lumbar disc herniation. The following measuring tools were used: visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and Macnab criteria. RESULTS: There were no severe complications such as dural tear or nerve root damage found in our study. The mean follow-up period was 19.7 months. The VAS score for leg and back pain decreased dramatically at 1 day postoperatively and kept decreasing until the follow-up visit at 3 months postoperatively, when it became stable at a low level. ODI kept improving until the follow-up visit at 6 months postoperatively when it reached a stable low level. Of the patients, 91% reported no longer having leg pain and 9% had occasional leg pain at last follow-up. CONCLUSIONS: PEID shows a satisfying outcome with a minimal rate of complications. It has the advantages of minimal traumatization and scar formation and is a safe and effective treatment for PLDH.

Dynamic microphysiological system chip platform for high-throughput, customizable, and multi-dimensional drug screening.

Spheroids and organoids have attracted significant attention as innovative models for disease modeling and drug screening. By employing diverse types of spheroids or organoids, it is feasible to establish microphysiological systems that enhance the precision of disease modeling and offer more dependable and comprehensive drug screening. High-throughput microphysiological systems that support optional, parallel testing of multiple drugs have promising applications in personalized medical treatment and drug research. However, establishing such a system is highly challenging and requires a multidisciplinary approach. This study introduces a dynamic Microphysiological System Chip Platform (MSCP) with multiple functional microstructures that encompass the mentioned advantages. We developed a high-throughput lung cancer spheroids model and an intestine-liver-heart-lung cancer microphysiological system for conducting parallel testing on four anti-lung cancer drugs, demonstrating the feasibility of the MSCP. This microphysiological system combines microscale and macroscale biomimetics to enable a comprehensive assessment of drug efficacy and side effects. Moreover, the microphysiological system enables evaluation of the real pharmacological effect of drug molecules reaching the target lesion after absorption by normal organs through fluid-based physiological communication. The MSCP could serves as a valuable platform for microphysiological system research, making significant contributions to disease modeling, drug development, and personalized medical treatment.

Patterning Techniques Based on Metallized Electrospun Nanofibers for Advanced Stretchable Electronics.

Stretchable electronics have experienced remarkable progress, especially in sensors and wireless communication systems, attributed to their ability to conformably contact with rough or uneven surfaces. However, the development of complex, multifunctional, and high-precision stretchable electronics faces substantial challenges, including instability at rigid-soft interfaces and incompatibility with traditional high-precision patterning technologies. Metallized electrospun nanofibers emerge as a promising conductive filler, offering exceptional stretchability, electrical conductivity, transparency, and compatibility with existing patterning technologies. Here, this review focuses on the fundamental properties, preparation processes, patterning technologies, and application scenarios of conductive stretchable composites based on metallized nanofibers. Initially, it introduces the fabrication processes of metallized electrospun nanofibers and their advantages over alternative materials. It then highlights recent progress in patterning technologies, including collector collection, vapor deposition with masks, and lithography, emphasizing their role in enhancing precision and integration. Furthermore, the review shows the broad applicability and potential influence of metallized electrospun nanofibers in various fields through their use in sensors, wireless systems, semiconductor devices, and intelligent healthcare solutions. Ultimately, this review seeks to spark further innovation and address the prevailing challenges in stretchable electronics, paving the way for future breakthroughs in this dynamic field.

A Study on Interobserver and Intraobserver Reliability of the Huashan Radiologic Classification System for Cervical Spinal Cord Injury Without Fracture and Dislocation.

STUDY DESIGN: Observational study. OBJECTIVE: To assess the reproducibility and reliability of the system. BACKGROUND: The Huashan radiologic classification system for cervical spinal cord injury without fracture and dislocation (CSCIWFD) was recently proposed and found useful for clinical practice. PATIENTS AND METHODS: Patients diagnosed with CSCIWFD between 2015 and 2021 were recruited. Six spine surgeons from different institutions, three experienced and other inexperienced respectively, were trained as observers of the system, and these surgeons classified the recruited patients using the system. Then, 8 weeks later, they repeated the classification on the same patients in a different order. The interobserver and intraobserver agreement between the results was analyzed using percentage agreement, weighted kappa, and Cohen kappa (κ) statistics. RESULTS: A total of 60 patients were included in the analysis. Type I was the most frequent type (29 cases, 48.3%), followed by type II (13 cases, 21.7%), type III (12 cases, 20%), and type IV (6 cases, 10%). For all the observers, experienced observers, and inexperienced observers, the overall agreement percentages were 77.6% (κ = 0.78), 84.4% (κ = 0.84), and 72.8% (κ = 0.74), respectively, indicating substantial to nearly perfect interobserver reproducibility. A higher level of agreement was found for differentiating type I from other types, with the percentage agreement ranging from 87.8% to 94.4% (κ= 0.74-0.88). For distinguishing compression on the spinal cord (types I and II vs types III and IV) among the different groups of observers, the percentage agreement was 97.8% (κ = 0.94), indicating nearly perfect reproducibility. As for intraobserver agreement, the percentage agreement ranged from 86.7% to 96.7% (κ = 0.78-0.95), indicating at least substantial reliability. CONCLUSIONS: The Huashan radiologic classification system for CSCIWFD was easy to learn and apply in a clinical environment, showing excellent reproducibility and reliability. Therefore, it would be promising to apply and promote this system for the precise evaluation and personalized treatment strategy.

[Development and validation of an automatic diagnostic tool for lumbar stability based on deep learning].

Objective: To develop an automatic diagnostic tool based on deep learning for lumbar spine stability and validate diagnostic accuracy. Methods: Preoperative lumbar hyper-flexion and hyper-extension X-ray films were collected from 153 patients with lumbar disease. The following 5 key points were marked by 3 orthopedic surgeons: L4 posteroinferior, anterior inferior angles as well as L5 posterosuperior, anterior superior, and posterior inferior angles. The labeling results of each surgeon were preserved independently, and a total of three sets of labeling results were obtained. A total of 306 lumbar X-ray films were randomly divided into training (n=156), validation (n=50), and test (n=100) sets in a ratio of 3∶1∶2. A new neural network architecture, Swin-PGNet was proposed, which was trained using annotated radiograph images to automatically locate the lumbar vertebral key points and calculate L4, 5 intervertebral Cobb angle and L4 lumbar sliding distance through the predicted key points. The mean error and intra-class correlation coefficient (ICC) were used as an evaluation index, to compare the differences between surgeons' annotations and Swin-PGNet on the three tasks (key point positioning, Cobb angle measurement, and lumbar sliding distance measurement). Meanwhile, the change of Cobb angle more than 11° was taken as the criterion of lumbar instability, and the lumbar sliding distance more than 3 mm was taken as the criterion of lumbar spondylolisthesis. The accuracy of surgeon annotation and Swin-PGNet in judging lumbar instability was compared. Results: ① Key point: The mean error of key point location by Swin-PGNet was (1.407±0.939) mm, and by different surgeons was (3.034±2.612) mm. ② Cobb angle: The mean error of Swin-PGNet was (2.062±1.352)° and the mean error of surgeons was (3.580±2.338)°. There was no significant difference between Swin-PGNet and surgeons (P>0.05), but there was a significant difference between different surgeons (P<0.05). ③ Lumbar sliding distance: The mean error of Swin-PGNet was (1.656±0.878) mm and the mean error of surgeons was (1.884±1.612) mm. There was no significant difference between Swin-PGNet and surgeons and between different surgeons (P>0.05). The accuracy of lumbar instability diagnosed by surgeons and Swin-PGNet was 75.3% and 84.0%, respectively. The accuracy of lumbar spondylolisthesis diagnosed by surgeons and Swin-PGNet was 70.7% and 71.3%, respectively. There was no significant difference between Swin-PGNet and surgeons, as well as between different surgeons (P>0.05). ④ Consistency of lumbar stability diagnosis: The ICC of Cobb angle among different surgeons was 0.913 [95%CI (0.898, 0.934)] (P<0.05), and the ICC of lumbar sliding distance was 0.741 [95%CI (0.729, 0.796)] (P<0.05). The result showed that the annotating of the three surgeons were consistent. The ICC of Cobb angle between Swin-PGNet and surgeons was 0.922 [95%CI (0.891, 0.938)] (P<0.05), and the ICC of lumbar sliding distance was 0.748 [95%CI(0.726, 0.783)] (P<0.05). The result showed that the annotating of Swin-PGNet were consistent with those of surgeons. Conclusion: The automatic diagnostic tool for lumbar instability constructed based on deep learning can realize the automatic identification of lumbar instability and spondylolisthesis accurately and conveniently, which can effectively assist clinical diagnosis.

The Influence of Screw Positioning on Cage Subsidence in Patients with Oblique Lumbar Interbody Fusion Combined with Anterolateral Fixation.

OBJECTIVES: Cage subsidence (CS) has been reported to be one of the most common complications following oblique lumbar interbody fusion (OLIF). To reduce the incidence of CS and improve intervertebral fusion rates, anterolateral fixation (AF) has been gradually proposed. However, the incidence of CS in patients with oblique lumbar interbody fusion combined with anterolateral fixation (OLIF-AF) is still controversial. Additionally, there is a lack of consensus regarding the optimal placement of screws for OLIF-AF, and the impact of screw placement on the incidence of CS has yet to be thoroughly investigated and validated. The objective of this investigation was to examine the correlation between screw placements and CS and to establish an optimized approach for implantation in OLIF-AF. METHODS: A retrospective cohort study was undertaken. From October 2017 to December 2020, a total of 103 patients who received L4/5 OLIF-AF for lumbar spinal stenosis or spondylolisthesis or degenerative instability in our department were followed up for more than 12 months. Demographic and radiographic data of these patients were collected. Additionally, screw placement related parameters, including trajectory and position, were measured by anterior-posterior X-ray and axial CT. Analysis was done by chi-square, independent t-test, univariable and multivariable binary logistic regression to explore the correlation between screw placements and CS. Finally, the receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive ability of screw placement-related parameters. RESULTS: A total of 103 patients were included, and CS was found in 28 (27.18%) patients. Univariable analysis was firstly performed for each parameter. Next, variables with p-value of <0.05, including bone mineral density (BMD), concave morphology, and screw placement-related parameters were included in the multivariate logistic regression analysis. Significant predictor factors for subsidence were coronal plane angle (CPA) (OR 0.580 ± 0.208, 95% CI 1.187-2.684), implantation point (IP) (L4) (OR 5.732 ± 2.737, 95% CI 1.445-12.166), and IP (L5) (OR 7.160 ± 3.480, 95% CI 1.405-28.683). Furthermore, ROC curves showed that the predictive accuracy of CS was 88.1% for CPA, 77.6% for IP (L4) and 80.9% for IP (L5). CONCLUSIONS: We demonstrate that the trajectory of vertebral screws, including angle and position, was closely related to CS. Inserting screws parallel to each other and as close to the endplate as possible while keeping the cage inside the range of the superior and inferior screws are an optimal implantation strategy for OLIF-AF.

Oblique lumbar interbody fusion combined with stress end plate augmentation and anterolateral screw fixation for degenerative lumbar spinal stenosis with osteoporosis: a matched-pair case-controlled study.

BACKGROUND CONTEXT: Oblique lumbar interbody fusion (OLIF) has been proven to be effective in treating degenerative lumbar spinal stenosis (DLSS). Whether OLIF is suitable for treating patients with DLSS with osteoporosis (OP) is still controversial. Bone cement augmentation is widely used to enhance the internal fixation strength of osteoporotic spines. However, the effectiveness of OLIF combined with bone cement stress end plate augmentation (SEA) and anterolateral screw fixation (AF) for DLSS with OP have not confirmed yet. PURPOSE: To evaluate the clinical, radiological, and functional outcomes of OLIF-AF versus OLIF-AF-SEA in the treatment of DLSS with OP. STUDY DESIGN: Retrospective case-control study. PATIENT SAMPLE: A total of 60 patients with OP managed for DLSS at L4-L5. OUTCOME MEASURES: Visual analog scale (VAS) score of the lower back and leg, Oswestry Disability Index (ODI), disk height (DH), lumbar lordosis (LL), segmental lordosis (SL), cage subsidence and fusion rate. METHODS: The study was performed as a retrospective matched-pair case‒controlled study. Patients with OP managed for DLSS at L4-L5 between October 2017 and June 2020 and completed at least 2 years of follow-up were included, which were 30 patients treated by OLIF-AF and 30 patients undergoing OLIF-AF-SEA. The demographics and radiographic data, fusion status and functional outcomes were therefore compared to evaluate the efficacy of the two approaches. RESULTS: Pain and disability improved similarly in both groups at the 24-month follow-up. However, the SEA group had lower pain and functional disability at 3 months postoperatively (p<.05). The mean postoperative disc height decrease (△DH) was significantly lower in the SEA group than in the control group (1.17±0.81 mm vs 2.89±2.03 mm; p<.001). There was no significant difference in lumbar lordosis (LL) or segmental lordosis (SL) between the groups preoperatively and 1 day postoperatively. However, a statistically significant difference was observed in SL and LL between the groups at 24 months postoperatively (p<.05). CS was observed in 4 cases (13.33%) in the SEA group and 17 cases (56.67%) in the control group (p<.001). A nonsignificant difference was observed in the fusion rate between the SEA and control groups (p=.347) at 24 months postoperatively. CONCLUSIONS: This study revealed that OLIF-AF-SEA was safe and effective in the treatment of DLSS with OP. Compared with OLIF-AF, OLIF-AF-SEA results in a minor postoperative disc height decrease, a lower rate of CS, better sagittal balance, and no adverse effect on interbody fusion.

[Research progress of spontaneous facet fusion after lumbar spine surgery].

Objective: To summarize the research progress on spontaneous facet fusion (SFF) after lumbar spine surgery, and provide reference for further research on SFF. Methods: The definition, development, clinical significance, and related influence factors of SFF were throughout reviewed by referring to relevant domestic and foreign literature in recent years. Results: SFF is a phenomenon of joint space disappearance and fusion of upper and lower articular processes, which starts in a ring shape from the outermost edges to the central regions. Currently reported SFF occurred after posterior lumbar pedicle screw fixation. SFF may increase the stability of surgical segments and relieve clinical symptoms of patients. SFF is closely related to the method of lumbar internal fixation, facet osteoarthritis, interbody fusion, age, body mass index, type B fracture (according to AO classification), and the operative segment. Conclusion: Most reported SFF occur after posterior lumbar pedicle screw fixation, which can increase lumbar stability, but the mechanism and influencing factors remain to be further clarified.

[Research progress of effect of cage height on outcomes of lumbar interbody fusion surgery].

Objective: To summarize the effect of cage height on outcomes of lumbar interbody fusion surgery and the importance of the cage height selection. Methods: The related literature was widely reviewed to summarize the research progress on the complications caused by inappropriate height of the cage and the methods of selecting cage height. Results: Inappropriate height of the cage can lead to endplate injury, cage subsidence, internal fixation failure, adjacent segmental degeneration, over-distraction related pain, insufficient indirect decompression, instability of operation segment, poor interbody fusion, poor sequence of spine, and cage displacement. At present, the selection of the cage height is based on the results of the intraoperative model test, which is reliable but high requirements for surgical experience and hard to standardize. Conclusion: The inappropriate height of the cage may have an adverse impact on the postoperative outcome of patients. It is important to develop a selection standard of the cage height by screening the related influential factors.

Whether Anterolateral Single Rod Can Maintain the Surgical Outcomes Following Oblique Lumbar Interbody Fusion for Double-Segment Disc Disease.

OBJECTIVE: To evaluate the outcomes of oblique lumbar interbody fusion (OLIF) combined with anterolateral single-rod screw fixation (AF) in treating two-segment lumbar degenerative disc disease (LDDD) and to determine whether AF can maintain the surgical results. METHODS: A retrospective analysis was performed on patients who underwent OLIF combined with AF (OLIF-AF) for LDDD at the L3-5 levels between October 2017 and May 2018. A total of 84 patients, including 44 males and 40 females, with a mean age of 62.8 ± 6.8 years, who completed the 12-month follow-up were eventually enrolled. Clinical outcomes, including the Oswestry Disability Index (ODI), visual analog scale (VAS) score for the low back and leg, and radiographic parameters, including the cross-sectional area (CSA) of the spinal canal, disc height (DH), foraminal height (FH), degree of upper vertebral slippage (DUVS), segmental lumbar lordosis (SL), fusion rate, and lumbar lordosis (LL), were recorded before surgery and 1 and 12 months after surgery. Surgical-related complications, including cage subsidence (CS), were also evaluated. The local radiographic parameters were compared between L3-4 and L4-5. The clinical results and all radiographic parameters were compared between patients with and without CS. RESULTS: Significant improvements were observed in radiographic parameters 1 day postoperatively (p < 0.05). Local radiological parameters in L4-5 had a significant decrease at 12 months postoperatively (p < 0.05), while they were well-maintained at L3-4 throughout the follow-up period (p > 0.05). CS was observed in 26 segments (15.5%). Endplate injury was observed in four segments (2.4%). There was no significant difference in the fusion rate between the segments with and without CS (p = 0.355). The clinical results improved significantly after surgery (p < 0.05), and no significant difference was observed between the groups with and without CS (p > 0.05). CONCLUSIONS: Anterolateral fixation combined with OLIF provides sufficient stability to sustain most radiological improvements in treating double-segment LDDD. Subsidence was the most common complication, which was prone to occur in L4-5 compared to L3-4, but did not impede the fusion process or diminish the surgical results.

Comparing the medium-term outcomes of lumbar interbody fusion via transforaminal and oblique approach in treating lumbar degenerative disc diseases.

BACKGROUND CONTEXT: Oblique lumbar interbody fusion (OLIF) has been proven to be effective in treating lumbar degenerative disorders (LDDs) via indirect decompression. However, its superiority over transforaminal lumbar interbody fusion (TLIF) remains questionable, especially in terms of medium-term follow-up. PURPOSE: To compare the medium-term clinical and radiological outcomes of TLIF and OLIF in treating patients with LDDs. STUDY DESIGN: Retrospective comparative study. PATIENT SAMPLE: Fifty-two patients treated by TLIF and forty-six patients treated by OLIF. OUTCOME MEASURES: Clinical records including the visual analog scale (VAS) score of the lower back and leg and the Oswestry Disability Index (ODI). Radiological records including disk height (DH), lumbar lordosis (LL), segmental lordosis (SL), the cross-sectional area (CSA) of the spinal canal, and fusion rate. Surgical-related information and complications were also recorded. METHODS: A retrospective review was performed on patients who were surgically managed for LDDs at L4-5 between 2015 and 2017 and completed at least 4 years of follow-up. A total of 98 patients were analyzed, with 46 patients treated by OLIF combined with anterolateral single screw-rod fixation (OLIF-AF group), and 52 patients treated by TLIF (TLIF group). Parameters including postoperative outcomes and perioperative complications were compared with evaluate the efficacy of the two approaches. RESULTS: There was significantly less bleeding, surgical duration, and hospitalization in the OLIF-AF group than in the TLIF group. Significant improvements in the clinical score were achieved in both groups. However, the VAS score of the lower back was significantly higher in the TLIF group than in the OLIF-AF group throughout the whole follow-up period. Significantly higher expansion of the CSA was found in the TLIF group than in the OLIF-AF group. However, the improvements in DH, LL, and SL were significantly lower in the TLIF group. The fusion rate was significantly higher in the OLIF-AF group than in the TLIF group within 6 months postoperatively, and there was no significant difference between the two groups at the final record. No significant difference was found in the rate of overall complications between the two groups (25.0% vs. 23.9%, p=.545). The intraoperative complication rate in the TLIF group (13.5%) was slightly higher than that in the OLIF-AF group (6.5%) (p=.257). There was no significant difference in the incidence of adjacent segment disorder (ASD) between the two groups (7.7% vs. 10.9%, p=.422). Cage subsidence was slightly lower in the TLIF group (5.8%) than in the OLIF-AF group (13.0%) (p=.298). CONCLUSIONS: Both the TLIF and OLIF-AF approaches demonstrated good medium-term outcomes in treating LDDs. Compared with TLIF, OLIF-AF showed advantages in postoperative recovery, improvement of intervertebral space and lumbar sagittal balance, and early intervertebral fusion but was associated with inferior spinal canal decompression efficacy. The two approaches shared comparable overall complication rates. However, OLIF-AF tended to have fewer intraoperative complications, and a higher incidence of subsidence.