Lumbar spinal stenosis(LSS) is a common degenerative spinal disease. Over the past 30 years, under the concept of minimally invasive spine surgery (MISS), spinal endoscopy has seen significant advancements, particularly in endoscopic unilateral laminotomy for bilateral decompression (ULBD). This technique, utilizing a fluid medium and small incision, achieves spinal canal decompression while maintaining spinal stability, resulting in satisfactory clinical outcomes. However, endoscopic spinal decompression surgery still has some complications, such as nerve injury, dural tears, myeloid hypertension, and epidural hematomas. Some scholars have begun exploring robotic endoscopic spinal surgery to reduce complications and improve clinical outcomes. This article provides an overview of the current state of endoscopic treatment for LSS, aiming to equip surgeons with a comprehensive understanding of this surgical approach to deliver better patient care.

In order to provide more practicable and convenient continuing medical education for orthopedic surgeons in primary hospitals and expand the academic influence of expert lecturers and host hospitals in the region, our department hosted nine short-term training courses of orthopedic surgery jointly with primary hospitals, which lasted for 1 to 1.5 days on weekends from June 2001 to October 2017, with expert lectures as the main form. Traumatic orthopedics was the main topic, and most expert lecturers were orthopedic experts from famous hospitals within the province and the whole country, as well as the experts from the host hospital. More than 1200 orthopedic and surgical physicians in local districts and counties participated in the training, and excellent social effect has been achieved. For short-term orthopedic training jointly held with hospitals in prefecture-level cities, the topic of training should be carefully selected, and duration of the training and number of lecturers should be controlled, so as to achieve satisfactory social effects under the premise of low cost of administrative resources.

Thoracic ossification of ligament flavum (TOLF) is a chronic progressive disease presenting the heterotopic ossification of the ligamentum flavum of the thoracic spine, which leads to a series of symptoms and signs of thoracic spinal cord, nerveor vascular compression, with a high incidence in East Asian countries such as China and Japan. The pathology of TOLF is endochondral ossification in nature and surgical intervention is currently the only effective treatment due to conservative treatment does not work. The older age, the insidious onset, the various clinical manifestations of TOLF patients make the localization diagnosis and surgery management difficult and even bring about the high incidence of postoperative complications. Therefore, it is particularly important to study the mechanism of osteogenic differentiation of TOLF to find a way of early diagnosis and prevention. A variety of factors related to osteogenic differentiation of TOLF have been found, such as genetics, mechanical stimuli, molecular biological factors, metabolic and trace element abnormalities and so on. Moreover, molecular signaling pathways play a crucial role in regulating cell proliferation and directed differentiation. Therefore, this article reviews the confirmed relevant signaling pathways in the process of ligamentum flavum ossification, including bone morphogenetic protein (BMP) signaling pathway, mitogen-activated protein kinase (MAPK) signaling pathway, Wnt signaling pathway, Notch signaling pathway, STAT3 signaling pathway and other signaling pathways and factors, and also summarizes the promotion and inhibition of these signaling pathways in the osteogenic differentiation of ligamentum flavum cells, aiming at establishing a basis for the further research of the molecular biological mechanism of TOLF, and providing a possible direction for exploration of effective preventive and therapeutic targets.

Cervical spondylotic amyotrophy (CSA) has attracted more and more attention in recent years, according to early studies, it is based on cervical degeneration, and mainly characterized by segmental, asymmetric and stable muscular atrophy of upper extremities, with or without mild sensory abnormalities and spinal cord lesions (manifested as lower extremity symptoms and gait abnormalities), also known as Keegan′s cervical spondylosis. This review will focusing on recent research progress of CSA, and summarize and analyze the definition, pathogenesis, clinical manifestations, diagnosis and treatment of cervical spondylosis muscular atrophy.

Cervical spondylotic amyotrophy (CSA) has attracted more and more attention in recent years, according to early studies, it is based on cervical degeneration, and mainly characterized by segmental, asymmetric and stable muscular atrophy of upper extremities, with or without mild sensory abnormalities and spinal cord lesions (manifested as lower extremity symptoms and gait abnormalities), also known as Keegan′s cervical spondylosis. This review will focusing on recent research progress of CSA, and summarize and analyze the definition, pathogenesis, clinical manifestations, diagnosis and treatment of cervical spondylosis muscular atrophy.

Objective:To compare a novel kind of anatomical locking plate versus proximal humeral internal locking system (PHILOS) in the treatment of proximal humerus fractures.Methods:A retrospective study was performed in the 35 patients with proximal humerus fracture who had been operatively treated at Department of Orthopedics, The Third Hospital of Peking University from January 2020 to June 2021. They were 13 males and 22 females, aged from 24 to 83 years (average, 56.7 years). Of them, 14 were fixated by the novel anatomical locking plate and 21 by PHILOS. The 2 groups were compared in terms of gender, age, fracture type, operation time, intraoperative blood loss, hospital stay, University of California (UCLA) shoulder scores and Disability of Arm Shoulder and Hand (DASH) scores for the upper limb dysfunction at one month after operation and at the last follow-up, and postoperative complications.Results:There was no significant difference in the preoperative general data between the novel plate group and the PHILOS group, showing comparability between them ( P>0.05). All the patients were followed up for 6 to 21 months (mean, 11.3 months). In the novel anatomical plate group, the operation time was (83.9±29.2) min, the intraoperative blood loss was (36.4±27.1) mL, the hospital stay was (2.3±1.1) d, the UCLA score and DASH score at one month after operation were (20.1±4.7) points and (55.5±19.1) points, the UCLA score and DASH score at the last follow-up were (28.5±4.6) points and (25.1±24.4) points, respectively; 2 patients developed complications after operation. In the PHILOS group, the operation time was (85.0±38.8) min, the intraoperative blood loss was (62.9±46.8) mL, the hospital stay was (2.4±0.9) d, the UCLA score and DASH score at one month after operation were (21.0±3.8) points and (49.6±23.7) points, and the UCLA score and DASH score at the last follow-up were (28.0±5.1) points and (19.1±17.3) points, respectively; 3 patients developed complications after operation. There was no significant difference in all the above items between the 2 groups (all P>0.05). Conclusion:In the treatment of proximal humerus fractures, the novel anatomical locking plate is a feasible internal fixator because it is comparable to PHILOS in fine efficacy, good fracture healing, and satisfactory functional recovery of the shoulder joint.

Objectives:To investigate the risk factors of cage retropulsion(CR)after posterior lumbar inter-body fusion(PLIF).Methods:Retrospective analysis was made on 17 patients(13 males and 4 females,with an average age of 63.7±9.9 years)who underwent revision surgery due to CR after PLIF in our hospital from September 2017 to September 2021.And the patients were included into the CR group.Another 34 patients without CR were matched in a ratio of 2∶1 according to the same fusion and fixation segments,time of initial surgery(±1 year),gender,and age(±2 years),including 26 males and 8 females,with an average age of 65.2±10.2 years.They were included in the control group.In the CR group,the average number of fixed segments was 1.8±0.8,and the average number of fused segments was 1.5±0.6;The time of CR was 7(0.75-132)months after the first operation;15 patients had single segmental CR and 2 patients had two segmental CR.The lumbar lordosis(LL),pelvic tilt(PT),sacral slope(SS),and pelvic incidence(PI)were measured on full-spine X-ray before operation of the two groups of patients,the disc height(DH)of the diseased segment was mea-sured on lateral lumbar X-ray,and the intervertebral range of motion(ROM)was measured on flexion-exten-sion X-ray.The CT value of lumbar vertebrae was measured in CT examination before operation;The shape of disc was defined through MRI examination.The cage position was measured on X-ray immediately after operation(The ratio of the distance between the marker line of the posterior margin of the cage and the pos-terior upper margin of the lower vertebral body to the length of the upper endplate of the lower vertebra).The paired sample t-test was used for single factor analysis to analyze the data of the two groups,after which,the parameters with statistical significance were analyzed with logistic regression to determine the inde-pendent risk factors of CR.Results:The mean vertebral CT value in the CR group was lower than that in the control group(124.8±39.7 vs 147.7±38.2,P=0.011);The cage position in the CR group was more posterior than that in the control group(0.15±0.09 vs 0.31±0.07,P＜0.001).There was no significant difference between the two groups in LL(40.8°±12.9° vs 42.4°±7.5°,P=0.717),PT(19.6°±7.1° vs 17.1°±6.7°,P=0.356),SS(27.7°±6.5° vs 31.0°±4.3°,P=0.144),PI(44.3°±13.8° vs 44.7°±13.9°,P=0.926),DH(10.1±2.4mm vs 8.8±1.4mm,P=0.066),ROM(4.3°±2.8° vs 4.4°±2.2°,P=0.950),and Pear-shaped intervertebral discs(33.3％vs 21.4％,P=0.40).Logistic regression analysis showed that low vertebral CT value(osteoporosis)(OR=0.975,P=0.043)and cage po-sition(OR=28.393,P=0.003)were the independent risk factors.Conclusions:Osteoporosis and posterior placement of cage are the risk factors for CR after PLIF.

Objectives:To evaluate the biomechanical state of the I4-L5 segment after unilateral laminotomy for bilateral decompression(ULBD)surgery using finite element analysis,providing a theoretical basis for the treatment of lumbar degenerative diseases with ULBD.Methods:Thin-slice CT scan data from the lumbar spine of a healthy volunteer were extracted,and high-fidelity three-dimensional finite element methods were applied to establish normal I4-L5 model,post-ULBD surgery model,and post-lumbar fenestration(LF)surgery model.The L5 vertebral body's lower endplate was fully fixed in all the models,and a 500N axial load was applied at the L4 upper endplate,along with a 10N·m bending moment load in six directions of flexion,ex-tension,left lateral bending,right lateral bending,left rotation,and right rotation.Comparative analysis of the biomechanical characteristics such as intervertebral disc compression height,intervertebral range of motion(ROM),stress distribution within the intervertebral disc,and facet joint pressure was conducted under different loads for the three models.Results:The ROMs under six directions of movements were within the range of the measured results of previous cadaveric studies,verifying that the normal model was valid.Under the 500N axial load,the intervertebral disc compression heights for the normal model,post-ULBD and post-LF surgery models were 0.74mm,0.85mm,and 0.85mm,respectively.With an additional 10N·m bending moment load,the intervertebral ROM in flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation for the normal model were 6.1°,4.2°,5.1°,4.6°,2.9°,and 2.6°,respectively;for the post-ULBD model,they were 6.5°,4.8°,6.0°,5.2°,3.2°,and 2.9°,respectively;and for the post-LF model,they were 6.4°,4.6°,5.6°,5.1°,3.0°,and 2.8°,respectively.There was no significant difference in the stress dis-tribution within the intervertebral disc for the three models,with the maximum von Mises stress occurring at the outer annulus fibrosus on the compressed side of the disc.The maximum von Mises stress in the inter-vertebral disc for the normal model under flexion,extension,left lateral bending,right lateral bending,left ro-tation,and right rotation was 0.52MPa,0.66MPa,0.81 MPa,0.87MPa,0.46MPa,and 0.40MPa,respectively;for the post-ULBD model,it was 0.64MPa,0.76MPa,1.06MPa,1.13MPa,0.60MPa,and 0.64MPa,respectively;and for the post-LF model,it was 0.65MPa,0.80MPa,1.00MPa,1.06MPa,0.66MPa,and 0.65MPa,respec-tively.Significant facet joint contact pressure was observed under left and right rotation,with the normal mod-el showing contact pressure of 60N and 69N,the post-ULBD model showing 30N and 87N,and the post-LF model showing 79N and 120N.Conclusions:After ULBD surgery,there is an increase in lumbar interverte-bral disc compression height,intervertebral ROM,stress within the intervertebral disc,and facet joint pressure.Compared with LF surgery,ULBD has a smaller impact on the biomechanical stability of the lumbar segment.

Objective To investigate the clinical effect of normal pressure drainage immediately after posterior cervical expansive open-door laminoplasty(EOL).Methods A retrospective analysis was performed on 94 cases of posterior cervical EOL in our hospital from January 2023 to June 2023.The patients were divided into normal pressure drainage group(n=43)and negative pressure drainage group(n=51)according to the order of admission time.The time range of cases in the normal pressure group was from January to March 2023,while in the negative pressure group was from April to June 2023.The 24 h postoperative drainage volume,total postoperative drainage volume,drainage tube indwelling time,postoperative fever,incision infection,neck wound hematoma,Japanese Orthopaedics Association(JOA)score improvement rate before and after surgery,length of hospital stay,hospital cost and postoperative hemoglobin decline were compared between the two groups.Results The 24 h postoperative drainage volume of the normal pressure drainage group was significantly lower than that of the negative pressure drainage group[45(15-150)ml vs.170(70-400)ml,Z=-7.934,P=0.000].The total drainage volume in the normal pressure drainage group was significantly lower than that in the negative pressure drainage group[45(15-285)ml vs.315(165-730)ml,Z=-7.924,P=0.000].The drainage tube indwelling time was(27.1±13.9)h in the normal pressure drainage group and(82.2±20.6)h in the negative pressure drainage group,with statistically significant difference between the two groups(t=-14.933,P=0.000).The length of hospital stay was(3.5±1.1)d in the normal pressure drainage group and(5.6±0.8)din the negative pressure drainage group,with statistical significance between the two groups(t=-10.322,P=0.000).The postoperative hemoglobin decline was(13.9±3.1)g/L in the normal pressure drainage group and(16.5±7.2)g/L in the negative pressure drainage group,with statistically significant difference between the two groups(t=-2.165,P=0.033).The hospitalization cost was(3.00±0.30)ten thousand yuan in the normal pressure drainage group and(3.48±0.29)ten thousand yuan in the negative pressure drainage group,with statistically significant difference between the two groups(t=-7.924,P=0.000).There were no significant differences in intraoperative blood loss,postoperative fever and incision infection between the two groups(P＞0.05).There was no significant difference in the improvement rate of JOA score between the two groups during 3 months of follow-ups(t=0.861,P=0.391).Conclusion After posterior cervical EOL,normal pressure drainage reduces the postoperative drainage flow,indwelling time of drainage tube,hospital stay,and hospitalization cost,and does not increase postoperative hematoma,fever and wound infection and other complications,the clinical effect being significant.

Spinal metastases may cause pain,pathological fracture and/or neurological symptoms.The most common treatment of spinal metastases is conservative therapy.Surgical intervention is necessary when there are pathological and/or neurological deficits.Total en bloc spondylectomy (TES) has lower local recurrence rate and may be applicable to a patient with single metastatic tumor and a long survival expectancy,While debulking surgery is less risky and higher recurrence rate.Conventional radiotherapy is a kind of effective supplement to reduce the local recurrence rate in spinal metastases.However,the local dose is often failed to reach the effective dose because of the close connection of tumor and spinal cord and it is less effective for relatively radioresistant histologies.With the development of radiotherapy technology,spinal radiotherapy has become increasingly accurate to avoid of spinal cord injury.In addition,conventional radioresistant tumors has become treatable with high-dose stereotactic body radiotherapy (SBRT).At the same time,SBRT is also an important basis for the implementation of separation surgery of spinal metastases.Separation surgery is to separate the tumor and dura and achieve circumferential decompression and stabilization through posterior approach.As a result,a high-dose SBRT can be performed because of the small interspace to protect the spinal cord,which greatly reduces the local recurrence rate.Compared with TES,separation surgery combined with high-dose radiotherapy not only reduces the difficulty of surgery,but also has a good local control rate,which is a relatively "minimally invasive" strategy.Separation surgery is particularly suitable for patients with high-grade epidural spinal cord compression and moderately sensitive or insensitive to radiotherapy.Although the concept of separation surgery has been proposed for several years,only a few applications have been reported in foreign literature and fewer in domestic literature.This article aims to summarize the relevant concepts and clinical applications of separation surgery in spine metastases and to provide a reference for the treatment of spinal metastases.