Is Dynesys dynamic stabilization system superior to posterior lumbar fusion in the treatment of lumbar degenerative diseases?

Dynesys,a pedicle-based dynamic stabilization system,was introduced to overcome some undesirable complications of fusion procedures.Nevertheless,the theoretical advantages of Dynesys over fusion have not been clearly confirmed.The purpose of this editorial was to compare clinical and radiological outcomes of patients who underwent Dynesys system with those who underwent posterior lumbar fusion according to the existing literature and to see if the application of the Dynesys system is superior to the traditional lumbar fusion surgery.According to published clinical reports,the short-term effects of the Dynesys dynamic stabilization system are similar to that of traditional lumbar fusion surgery.Three comparative studies of Dynesys dynamic stabilization and fusion surgery with medium-term follow-up are encouraging.However,the results from four single-treatment-arm and small-sample studies of case series with long-term follow-up were not encouraging.In the present circumstances,it is not possible to conclude that the Dynesys dynamic stabilization system is superior to fusion surgery for lumbar degenerative diseases.

Potential contribution of pedicle screw design to loosening rate in patients with degenerative diseases of the lumbar spine:An observational study

BACKGROUND The majority of published data report the results of biomechanical tests of various design pedicle screw performance.The clinical relevance and relative contribution of screw design to instrumentation stability have been insufficiently studied.AIM To estimate the contribution of screw design to rate of pedicle screw loosening in patients with degenerative diseases of the lumbar spine.METHODS This study is a prospective evaluation of 175 patients with degenerative diseases and instability of the lumbar spine segments.Participants underwent spinal instrumentation employing pedicle screws with posterior only or transforaminal interbody fusion.Follow-up was for 18 mo.Patients with signs of pedicle screw loosening on computed tomography were registered;logistic regression analysis was used to identify the factors that influenced the rate of loosening.RESULTS Parameters included in the analysis were screw geometry,type of thread,external and internal screw diameter and helical pitch,bone density in Hounsfield units,number of levels fused,instrumentation without anterior support,laminectomy,and unilateral and bilateral total facet joint resection.The rate of screw loosening decreased with the increment in outer diameter,decrease in core diameter and helical pitch.The rate of screw loosening correlated positively with the number of fused levels and decreasing bone density.Bilateral facet joint removal significantly favored pedicle screw loosening.The influence of other factors was insignificant.CONCLUSION Screw parameters had a significant impact on the loosening rate along with bone quality characteristics,the number of levels fused and the extensiveness of decompression.The significance of the influence of screw parameters was comparable to those of patient-and surgery-related factors.Pedicle screw loosening was influenced by helical pitch,inner and outer diameter,but screw geometry and thread type were insignificant factors.

Staining neurons with Golgi techniques in degenerative diseases ofthe brain

A detailed morphological study of neurons in healthy and pathological conditions requires reasonably a number of special techniques, which may visualize the majority of neu- rons in a thick three-dimensional arrangement. A detailed visualization of neurons must include the cell body, most of the dendritic arbor, the dendritic spines, the axon, the axonal collaterals and the synapses. An ideal morphological technique for the study of degeneration and regeneration processes of the central nervous system must also visualize clearly the long and short neuronal circuits, as well as the dendritic and axonal bands and tracks.

Application of Finite Element Analysis in Biomechanical Research of Degenerative Diseases of Lumbar Spine

As the elderly population continues to grow, the number of patients with low back pain is gradually increasing. Among them, Lumbar Degenerative Diseases (LDD) is one of the major contributors to low back pain. Biomechanical in vivo studies of the lumbar spine are mainly performed by implants or imaging data to record the real-time changes of form and stress on the intervertebral disc during motion. However, the current developments are slow due to the technological and ethical limitations. In vitro experiments include animal experiments and cadaver experiments, which are difficult to operate or differ greatly from normal human structures, and the results still need to be verified repeatedly to test their accuracy. As for finite element method, it is relatively low cost and can repeat the experimental results. Therefore, we believe that finite element analysis plays an extremely important role in biomechanical research, especially in analyzing the relationship between different surgical models and the degeneration caused by different mechanics.

Unilateral pedicle screw fixation combined with lumbar interbody fusion for the treatment of lumbar degenerative diseases

Objective To explore the feasibility and efficiency of the treatment of lumbar degenerative diseases after transforaminal lumbar interbody fusion (TLIF) and posterolateral fusion (PLF) procedures in which unilateral pedicle screw fixation was used.

Trans-facet joints approach to treat thoracic degenerative diseases with anterior compression

Objective To investigate the clinical outcomes of trans-facet joints approach to treat thoracic degenerative disease with anterior compression.Methods From January 2003 to December 2009,22 patients with thoracic myelopathy caused by

A comparison of unilateral and bilateral pedicle screw fixation combined with transforaminal lumbar interbody fusion for lumbar degenerative diseases

Background Bilateral transpedicular screw fixation in conjunction with interbody fusion is widely used to treat lumbar degenerative diseases; however, there are some disadvantages of using this fixation system. This study comparatively analyzes the results of unilateral and bilateral pedicle screw fixation combined with transforaminal lumbar interbody fusion （TLIF） for one-level lumbar degenerative diseases. Methods Sixty-six cases with one-level lumbar degenerative diseases were studied. The patients were divided according to surgical approach into a unilateral group （Group A） and a bilateral group （Group B）. The patients were evaluated for pain by visual analog scale （VAS） and Oswestry Disability Index （ODI）. Operating time, blood loss, duration of hospitalization, and complication rate were also evaluated. Patients were examined at 1, 3, 6, and 12 months postoperatively and every year thereafter. Results Group A patients＇ average preoperative VAS and ODI scores were 7.03 ±0.98 and （64.22±6.38）%, respectively, significantly decreased to 2.91 ± 0.88 and （14.42＋2.08）%, respectively, at the last follow-up （P = 0.000）. In Group B, the average preoperative VAS and ODI scores were 6.79±0.86 and （63.22±4.70）%, respectively, significantly decreased to 3.12±0.96 and （14.62±2.08）%, respectively, at the last follow-up （P=-0.000）. No significant difference in the duration of hospitalization was found between groups. Operating time and blood loss of （125.9±13.0） minutes and （211.4±28.3） ml, respectively, in Group A were significantly less than （165.2±15.3） minutes and （258.6±18.3） ml, respectively, in Group B （P=0.000）. All patients achieved good bone union and had no pseudarthrosis at the last follow-up. Conclusions There are no clinical differences between unilateral and bilateral pedicle screw fixation combined with TLIF for one-level lumbar degenerative diseases. Unilateral fixation reduces operating time, bleeding, and cost of hospitalization.

Endplate role in the degenerative disc disease:A brief review

The degenerative disease of the intervertebral disc is nowadays an important health problem,which has still not been understood and solved adequately.The vertebral endplate is regarded as one of the vital elements in the structure of the intervertebral disc.Its constituent cells,the chondrocytes in the endplate,may also be involved in the process of the intervertebral disc degeneration and their role is central both under physiological and pathological conditions.They main functions include a role in homeostasis of the extracellular environment of the intervertebral disc,metabolic support and nutrition of the discal nucleus and annulus beneath and the preservation of the extracellular matrix.Therefore,it is understandable that the cells in the endplate have been in the centre of research from several viewpoints,such as development,degeneration and growth,reparation and remodelling,as well as treatment strategies.In this article,we briefly review the importance of vertebral endplate,which are often overlooked,in the intervertebral disc degeneration.

Promising use of metformin in treating neurological disorders:biomarker-guided therapies

Neurological disorders are a diverse group of conditions that affect the nervous system and include neurodegenerative diseases(Alzheimer’s disease,multiple sclerosis,Parkinson’s disease,Huntington’s disease),cerebrovascular conditions(stroke),and neurodevelopmental disorders(autism spectrum disorder).Although they affect millions of individuals around the world,only a limited number of effective treatment options are available today.Since most neurological disorders express mitochondria-related metabolic perturbations,metformin,a biguanide type II antidiabetic drug,has attracted a lot of attention to be repurposed to treat neurological disorders by correcting their perturbed energy metabolism.However,controversial research emerges regarding the beneficial/detrimental effects of metformin on these neurological disorders.Given that most neurological disorders have complex etiology in their pathophysiology and are influenced by various risk factors such as aging,lifestyle,genetics,and environment,it is important to identify perturbed molecular functions that can be targeted by metformin in these neurological disorders.These molecules can then be used as biomarkers to stratify subpopulations of patients who show distinct molecular/pathological properties and can respond to metformin treatment,ultimately developing targeted therapy.In this review,we will discuss mitochondria-related metabolic perturbations and impaired molecular pathways in these neurological disorders and how these can be used as biomarkers to guide metformin-responsive treatment for the targeted therapy to treat neurological disorders.

Cortical bone trajectory screws in the treatment of lumbar degenerative disc disease in patients with osteoporosis

Lumbar degenerative disc disease(DDD)in the elderly population remains a global health problem,especially in patients with osteoporosis.Osteoporosis in the elderly can cause failure of internal fixation.Cortical bone trajectory(CBT)is an effective,safe and minimally invasive technique for the treatment of lumbar DDD in patients with osteoporosis.In this review,we analyzed the anatomy,biomechanics,and advantages of the CBT technique in lumbar DDD and revision surgery.Additionally,the clinical trials and case reports,indications,advancements and limitations of this technique were further discussed and reviewed.Finally,we concluded that the CBT technique can be a practical,effective and safe alternative to traditional pedicle screw fixation,especially in DDD patients with osteoporosis.

Outcomes of cervical degenerative disc disease treated by anterior cervical discectomy and fusion with self-locking fusion cage

BACKGROUND Cervical degenerative disc(CDD)disease is a common type of spondylosis.Although anterior cervical discectomy and fusion(ACDF)is the preferred treatment for CDD disease,internal fixation with a titanium plate may cause various complications.The invention of the ACDF with a self-locking fusion cage(ROI-C)has effectively decreased the incidence of postoperative complications.AIM To observe the outcomes of CDD disease treated by ACDF with a ROI-C.METHODS Ninety patients with CDD disease treated at our hospital from March 2019 to March 2021 were included.They were divided into two groups(control group and observation group,n=45 in each)using a random number table.Patients in the control group received ACDF plus internal fixation with a titanium plate.Those in the observation group received ACDF+ROI-C placement.The two groups of patients were compared in terms of surgical parameters,pain,cervical spine function,range of motion,and complications.RESULTS The two groups of patients showed no significant differences in surgical time,blood loss,drainage volume,and length of hospital stay(P>0.05).No significant differences in the visual analogue scale(VAS),Japanese Orthopedic Association(JOA),and neck disability index(NDI)scores were observed between the two groups before surgery(P>0.05).The VAS and NDI scores in the observation group were considerably lower than those in the control group after surgery;however,the JOA scores in the observation group were significantly higher than those in the control group(P<0.05).No significant differences were observed in cervical disc height and the range of motion of the superior or inferior adjacent vertebrae between the two groups before surgery(P>0.05).The disc height in the observation group was larger than that in the control group after surgery.The range of motion of both the superior and inferior adjacent vertebrae was significantly smaller in the observation group than in the control group(P<0.05).The incidence of complications was only 2.22% in the observation group compared to 15.56% in the control group,and the difference was statistically significant(P<0.05).CONCLUSION Cervical spine function restoration was better with ROI-C with internal fixation in ACDF than with conventional titanium plates in ACDF for CDD disease.

Follow-up Study on the Motion Range after Treatment of Degenerative Disc Disease with the Bryan Cervical Disc Prosthesis

This study examined effect of a new intervertebral cervical disc prosthesis in relieving the neurological symptoms and signs, improving the patients＇ ability to perform daily activities, reducing pain, and maintaining the stability and segmental motion. From December 2003 to October 2004, 12 patients, who had received 14 replacements of cervical artificial discs, were followed-up for 2 to 8 months （with a mean of 5.2 months）. Of them 5 had cervical spondylotic myelopathy and 7 had cervical disc herniation. The patients included 7 males and 5 females, with their age ranging from 35 to 62 y and a mean of 50.3 y. Single-level replacements were performed in 10 cases and 2 cases received two-level replacement. Operation time of the single-level surgery averaged 130±50 rain and the time of two-level surgery was 165±53 min on average （from skin incision to skin suturing）. Neurological or vascular complications during or after surgery was not observed. Japanese Orthopedic Association scores （JOA scores） increased from 8.6 to 15.8 on average. There was no prothesis subsidence or excursion. Replaced segments were stable and the range of motion was partially restored, being 4.68° （3.6°-6.1°） in flexion and extension position and 3.51 ° （2.5°-4.6°）, 3.42° （2.6°-4.3°） in left and right bending position. No obvious loss of physiological curvature was noted. CT or MRI follow-up showed that excursion was less than 1.5 mm） in 2 of 14 levels and between 1.5 mm and 3 mm） in 1 of 14 levels. No ossification in the replaced levels was observed. It is concluded that satisfactory short-term results were achieved in the 12 cases of artificial disc replacements. Different from anterior cervical discectomy and fusion, the replacement could achieve quick functional recovery and did not lead to the movement limitation of cervical vertebrae. At least a 5-years follow-up was needed to assess the long-term effect of the prosthesis on its neighboring segments.

Cortical bone trajectory fixation in cemented vertebrae in lumbar degenerative disease:A case report

BACKGROUND Percutaneous vertebroplasty(PVP)has been widely used in osteoporotic vertebral compression fracture(OVCF).Following surgery,the bone cement would be positioned permanently.However,in some cases of lumbar degenerative disease,the cemented vertebrae needs to be fixed after decompression and fusion procedure.It is difficult to implant traditional pedicle screws into the cemented vertebrae because of the bone cement filling.At present,the main treatment strategy is to skip the cemented vertebra and conduct a long segment fixation.This article presents a cortical bone trajectory(CBT)fixation technique for cemented vertebrae.CASE SUMMARY PVP involving the L3 and L4 was performed in an 82-year-old man due to OVCF.During the surgery,bone cement leakage occurred,resulting in compression of the root of the right L3 nerve.We performed a partial facetectomy to retrieve the leaked bone cement and to relieve the patient’s neurological symptoms.After 3 mo,the patient developed lumbar disc herniation in L3/4,potentially due to instability caused by the previous surgery.Therefore,it was necessary to perform intervertebral fusion and fixation.It was difficult to implant traditional trajectory pedicle screws in L3 and L4 because of the bone cement filling.Hence,we implanted CBT screws in the L3 and L4 vertebrae.As a result,the patient’s symptoms resolved and he reported satisfaction with the surgery at follow-up after 8 mo.CONCLUSION It is feasible to utilize CBT in cemented vertebrae for the treatment of lumbar degenerative disease.

Clinical features and surgical treatment of the coexistence of cervical,thoracic and lumber degenerative disease

Objective To discuss clinical features and surgical treatment of the coexistence of cervical,thoracic and lumber degenerative disease. Methods From January 2004 to December 2008,79 cases with the coexistence of cervical,thoracic

Retrospective Case Series of Porous Titanium Cages in Oblique Lumbar Interbody Fusion Surgery Assessing Subsidence, Fusion and Functional Outcomes

Purpose: Implant subsidence is a possible complication of spinal interbody fusion. We aim to evaluate porous titanium cages subsidence, fusion and functional outcomes in patients subjected to oblique lumbar interbody fusion (OLIF) with these novel devices. Methods: Our institutional review board approved a single-center experience which included 60 patients who underwent OLIF from June 2018 to June 2020 utilizing the porous titanium implants. Data was collected in accordance with the Declaration of Helsinki, and written informed consent was obtained. Imaging studies including radiographs 1, 3, 6 and 12 months and computed tomography (CT) scan at 6 months obtained during routine postoperative follow-up visits, were studied for signs of implant subsidence, fusion and clinical parameters to determine the effectiveness of surgery such as Oswestry disability index (ODI). Results: Radiographic subsidence occurred in 1 out of 89 porous titanium interbody cages (1.1%). No subsidence was observed in the posterior screws and rods fixation group (N = 57). However, one case of subsidence occurred in the lateral plate fixation group (N = 3). The subsidence occurred in an osteoporotic elderly patient operated for adjacent segment disease, and she was later revised with posterior instrumentation using cemented screws and rods. She had an uneventful recovery. Fusion rates were evaluated under CT scan at 6 months with a rate of 88%. In terms of clinical outcomes, ODI decreased significantly from 20.3 preop to 10.7 postop with a P-value Conclusions: In our study, the subsidence rate was lower than previously reported in the literature. Also, we had good fusion rates at 6 months likely due to the porous titanium cages use. We had no subsidence in the posterior instrumented group and one case in the lateral fixation group with improved clinical outcomes.

Polyphenols as potential enhancers of stem cell therapy against neurodegeneration

The potential of polyphenols for treating chronic-degenerative diseases(particularly neurodegenerative diseases)is attractive.However,the selection of the best polyphenol for each treatment,the mechanisms by which they act,and their efficacy are frequently discussed.In this review,the basics and the advances in the field,as well as suggestions for using natural and synthetic polyphenols alone or in a combinatorial strategy with stem cell assays,are compiled and discussed.Thus,stem cells exhibit several responses when polyphenols are added to their environment,which could provide us with knowledge for advancing the elucidation of the origin of neurodegeneration.But also,polyphenols are being included in the innovative strategies of novel therapies for treating neurodegenerative diseases as well as metabolic diseases related to neurodegeneration.In this regard,flavonoid compounds are suggested as the best natural polyphenols due to their several mechanisms for acting in ameliorative effects;but increasing reports are involving other polyphenols.Even if some facts limiting bioactivity prevent them from conventional use,some natural polyphenols and derivatives hold the promise for being improved compounds,judged by their induced effects.The current results suggest polyphenols as enhancers of stem cell therapy against the targeted diseases.

Synaptic aging disrupts synaptic morphology and function in cerebellar Purkinje cells

Synapses are key structures in neural networks,and are involved in learning and memory in the central nervous system.Investigating synaptogenesis and synaptic aging is important in understanding neural development and neural degeneration in diseases such as Alzheimer disease and Parkinson’s disease.Our previous study found that synaptogenesis and synaptic maturation were harmonized with brain development and maturation.However,synaptic damage and loss in the aging cerebellum are not well understood.This study was designed to investigate the occurrence of synaptic aging in the cerebellum by observing the ultrastructural changes of dendritic spines and synapses in cerebellar Purkinje cells of aging mice.Immunocytochemistry,Di I diolistic assays,and transmission electron microscopy were used to visualize the morphological characteristics of synaptic buttons,dendritic spines and synapses of Purkinje cells in mice at various ages.With synaptic aging in the cerebellum,dendritic spines and synaptic buttons were lost,and the synaptic ultrastructure was altered,including a reduction in the number of synaptic vesicles and mitochondria in presynaptic termini and smaller thin specialized zones in pre-and post-synaptic membranes.These findings confirm that synaptic morphology and function is disrupted in aging synapses,which may be an important pathological cause of neurodegenerative diseases.

Human melanopsin-AAV2/8 transfection to retina transiently restores visual function in rd1 mice

AIM： To explore whether ectopic expression of human melanopsin can effectively and safely restore visual function in rd1 mice.· METHODS： Hematoxylin-eosin staining of retinal sections from rd1 mice was used to detect the thickness of the outer nuclear layer to determine the timing of surgery. We constructed a human melanopsinAAV2/8 viral vector and injected it into the subretinal space of rd1 mice. The Phoenix Micron IV system was used to exclude the aborted injections, and immunohistochemistry was used to validate the ectopic expression of human melanopsin. Furthermore, visual electrophysiology and behavioral tests were used to detect visual function 30 and 45 d after the injection. The structure of the retina was compared between the human melanopsin-injected group and phosphate buffer saline（PBS）-injected group.·RESULTS： Retinas of rd1 mice lost almost all of their photoreceptors on postnatal day 28（P28）. We therefore injected the human melanopsin-adeno-associated virus（AAV） 2/8 viral vector into P30 rd1 mice. After excluding aborted injections, we used immunohistochemistry of the whole mount retina to confirm the ectopic expression of human melanopsin by co-expression of human melanopsin and YFP that was carried by a viral vector. At30 d post-injection, visual electrophysiology and the behavioral test significantly improved. However,restoration of vision disappeared 45 d after human melanopsin injection. Notably, human melanopsin-injected mice did not show any structural differences in their retinas compared with PBS-injected mice.·CONCLUSION： Ectopic expression of human melanopsin effectively and safely restores visual function in rd1

The Integrative Five-Fluid Circulation System in the Human Body

Water is the key medium to transport numerous constituents and to provide a platform for physiological processes to take place in the living organisms in general;it also participates actively in many of these processes. In humans, there are different vehicles to contain water and its constituents. Our objective is to find out whether there is an overall water-base circulation system in the human body by analyzing the updated findings of different research groups on the physiological functions of various seemingly isolated fluid systems. By 1963, there were five separate fluid systems discovered in mammalians: (i) The Primo Vasculature Fluid (PVF) with protein precursors and micro cells held in the Primo Vasculature System (PVS). (ii) Blood with its constituents held in the cardio vasculature. (iii) Extracranial interstitial fluid (ISF) whose vehicle had a very irregular structure—the interstitium all over the body. (iv) The cerebrospinal fluid had been considered to be within the brain ventricles and spinal canal. (v) The extra-cranial lymphatic system which drained ISF, and had been known to join the subclavian vein. Fluid (i) was first reported in 1963 and fluids (ii) to (v) have been known for many decades, but the failure to detect a lymphatic system inside the skull has also been a mystery for many decades. The intra-cranial ISF (which we name as BISF) has drawn little attention, apart from discussing the mechanism of the blood-brain-barrier. During the past decade, there has been direct evidence indicating that CSF and BISF are actually mixed. After that, the intracranial lymphatic system was discovered and confirmed in animal models only slightly over one year back, and we called such fluid as glymphatic-fluid. After reviewing the stated “classical” five fluid systems together with the new findings in Sections 2 - 7, we propose, for the first time, that the PVF, the blood, ISF, a mixture of CSF-BISF, and a mixture of glymphatic-fluid and lymph form an integrative circulation system in water base in the human and other mammalian bodies, as schematically represented in the last section. In this paper, we point out the positive correlation of chronic neuro degenerative diseases such as Alzheimer’s disease, Parkinson’s diseases and the insufficient brain wastes clearance by the glymphatic system. We also discuss the role played by the venous vessels as part of such clearance in upright posture. Moreover, simple non-invasive maneuver techniques are introduced here, as one example of enhancement of glymphatic fluid flow out of the skull to join the lymphatic system. A series of questions are raised in Section 8, the answers to which would help us to understand the transition from physio- to pathological states in the development of many diseases. Detailed analysis of this paper leads us to consider that research in understanding this integrative circulation system is only at the infancy stage, and fluid dynamics investigation seems to be the plausible modality of approach in the near future.

Subretinal transplantation of mouse retinal progenitor cells

The development of cell replacement techniques is promising as a potential treatment for photoreceptor loss. However, the limited integration ability of donor and recipient cells presents a challenge following transplantation. In the present study, retinal progenitor cells （RPCs） were harvested from the neural retinas of enhanced green fluorescent protein mice on postnatal day 1, and expanded in a neurobasal medium supplemented with fetal bovine serum without endothelial growth factor. Using a confocal microscope, immunohistochemistry demonstrated that expanded RPCs in vitro maintain retinal stem cell properties and can be differentiated into photoreceptor cells. Three weeks after transplantation, subretinal transplanted RPCs were found to have migrated and integrated into the outer nuclear layer of recipient retinas with laser injury, some of the integrated cells had differentiated into photoreceptors, and a subpopulation of these cells expressed photoreceptor specific synaptic protein, appearing to form synaptic connections with bipolar cells. These results suggest that subretinal transplantation of RPCs may provide a feasible therapeutic strategy for the loss of retinal photoreceptor cells.