Dynamic Stabilization System Research Articles

Correlation of the single-segment dynamic stabilization with different segmental mobility and zygapophysial (facet) joint degeneration: a retrospective study in northern China

ObjectiveTo compare the clinical and radiographic outcomes of single-segment posterior decompression combined with two different non-fusion dynamic stabilization systems, Isobar EVO and Isobar TTL, in the context of facet joint degeneration and segmental mobility.MethodA retrospective study was conducted on 47 patients who underwent single-segment surgery at the L4/5 level using either the Isobar EVO (n = 23) or Isobar TTL (n = 24) systems. We assessed facet joint degeneration on both sides of the fixed (L3/4, L4/5) and superior adjacent (L2/3) segments using the Fujiwara MRI grading system. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain at baseline, 12 months, and 24 months postoperatively.ResultBoth groups exhibited significant facet joint degeneration at the fixed segments (L3/4 and L4/5) at 24 months. The TTL group also showed significant degeneration at the superior adjacent segment (L2/3), whereas the EVO group did not. Restoration of lumbar lordosis was significantly better in the EVO group. Pain and disability scores improved more in the EVO group than in the TTL group at both 12 and 24 months postoperatively.ConclusionThe Isobar EVO system, with its enhanced mobility, may delay facet joint degeneration in the superior adjacent segment compared to the Isobar TTL system. However, both systems result in degeneration at the fixed segment, indicating a need for further improvements to mimic the natural biomechanics of the spine more closely.

The Effect of Kinesio Taping on Lumbar Kinematic After Static Lumbar Flexion in Healthy Subjects

Introduction: The application of Kinesio taping (KT) is a rehabilitation technique used to provide muscle and joint support and stability, without limiting the range of motion (ROM). No study evaluated the effects of KT on lumbar flexion relaxation phenomenon and kinematic details after static flexion. This study aims to find out the results of KT on erector spinae (ES) muscle activity, flexion relaxation pattern, and trunk, lumbar, and hip range of motion in healthy subjects during static flexion Materials and Methods: This study used a two-factor within-group design. Twenty-two healthy female students participated in this study. We used surface electromyography (EMG) to assess ES muscle activity and measured kinematic information with data from the camera. Variables related to muscle activity and angles in forward bending movement before and after creep were investigated. The test was performed in two situations with and without the use of KT. Results: KT reduced the time of muscle activity during bending. Also, KT increased trunk, and hip angles at the end of forward flexion. In the lumbar extension phase, the ES muscles were activated later Conclusion: KT can prevent the increase of lumbar spine flexion angle due to the creep effect. It can be used to protect the strained viscoelastic structures and increase the involvement of cutaneous receptors. KT can act as a protector in the dynamic stabilization system of lumbar joints in flexion positions in healthy people.

Can Dynamic Spinal Stabilization Be an Alternative to Fusion Surgery in Adult Spinal Deformity Cases?

Rigid stabilization and fusion surgery are widely used for the correction of spinal sagittal and coronal imbalance (SCI). However, instrument failure, pseudoarthrosis, and adjacent segment disease are frequent complications of rigid stabilization and fusion surgery in elderly patients. In this study, we present the results of dynamic stabilization and 2-stage dynamic stabilization surgery for the treatment of spinal SCI. The advantages and disadvantages are discussed, especially as an alternative to fusion surgery. In our study, spinal, sagittal, and coronal deformities were corrected with dynamic stabilization performed in a single session in patients with good bone quality (without osteopenia and osteoporosis), while 2-stage surgery was performed in patients with poor bone quality (first stage: percutaneous placement of screws; second stage: placement of dynamic rods and correction of spinal SCI 4-6 months after the first stage). One-stage dynamic spinal instrumentation was applied to 20 of 25 patients with spinal SCI, and 2-stage dynamic spinal instrumentation was applied to the remaining 5 patients. Spinal SCI was corrected with these stabilization systems. At 2-year follow-up, no significant loss was observed in the instrumentation system, while no significant loss of correction was observed in sagittal and coronal deformities. In adult patients with spinal SCI, single or 2-stage dynamic stabilization is a viable alternative to fusion surgery due to the very low rate of instrument failure. This study questions the use of dynamic stabilization systems for the treatment of adult degenerative deformities.

A new method for restoring the liquid level at the intake of an electric drive pumping system

An analysis of the system for stabilizing the hydrodynamic level in the wellbore is presented. It is shown that hydraulic losses increase with increasing difference between the coordinates of the valve installation location and the liquid level, as well as with increasing valve length. A method is developed for determining the parameters of the dynamic level stabilization system in the wellbore. An algorithm is obtained and criteria for selecting standard sizes of system elements are determined. Keywords: electric centrifugal pump, bypass device, annular cavity. urazakk@mail.ru

Fault-tolerant controller based on artificial intelligence combined with terminal sliding mode and pre-described performance function applied on ship dynamic position stabilization systems

The presented study, develops an intelligent fault-tolerant controller to automatically control and maintain the position of a ship. The controller possesses the capabilities of holding the ship steady at a fixed position, automatically transferring the ship from one point to another, and tracking a target in the presence of various disturbances, uncertainties in the ship model, and thruster faults. A backstepping control approach based on the Terminal Sliding Mode method is employed to improve the accuracy of the controller. The aforesaid method guarantees time-limited convergence without relying on the initial conditions of system. A pre-described performance function (PPF) is utilized to ensure the performance in transient states and the calculations, which leads to the specific equations achievement for the study, which guarantees the system's stability. Environmental disturbances, uncertainties, and thruster faults are estimated using a Radial Basis Neural Network, allowing the controller to adapt to changes in the ship's environment and system uncertainties. The designed controller is proven to ensure the tracking error remains within a predefined range and can stabilize the ship system within a constant time without being influenced by the initial conditions. This stability is achieved in the presence of environmental disturbances, model uncertainties, and thruster faults, and the tracking error converges to a neighborhood near the origin. The controller is verified using a ship mode in the MATLAB environment, and the results show that the designed controller effectively controls the ship's position. The theoretical findings are successfully verified through these simulation tests.

Power distribution mechanisms with friction control in the transmission of a road train with an active trailer-dissolution

The article analyzes the experience of using gear controlled power distribution mechanisms in transport engineering as part of a dynamic stabilization system for high-speed ground vehicles. An overview of the sources on this issue is given. It is shown that the issue of increasing the lateral stability against skidding is relevant in modern conditions and has received a mathematical description mainly in the application to passenger cars. Attention is paid to theoretical studies of Russian scientists involved in the problem of power distribution control in transmissions of transport vehicles and tractors for various purposes. A solution to the problem of full control over the distribution of torques in a transmission containing several drive axles is proposed in the form of a structural diagram of a transmission based on the use of controlled gear power distribution mechanisms. The considered solutions are applicable for monohull vehicles and road trains with an active trailer link. Methods for determining external parameters (gamma of gear ratios) for interaxle and interwheel controlled power distribution mechanisms are proposed in the application to the case of turning a road train with an active trailer-dissolution having an electromechanical transmission.

Clinical and radiological analysis of the effects of three different lumbar transpedicular dynamic stabilization system on disc degeneration and regeneration.

This study aims to assess the clinical outcomes of three transpedicular dynamic systems in treating degenerative disc disease and evaluate their impact on both clinical and radiological aspects of the operated and adjacent segments. A total of 111 patients who underwent posterior transpedicular short-segment dynamic system procedures for treatment of degenerative disc disease were included. The patients were categorized into three groups, namely, Group 1 (Dynesys system, n = 38), Group 2 (Safinaz screw + PEEK rod, n = 37), and Group 3 (Safinaz screw + titanium rod, n = 36). Disc regeneration in the operated segment and disc degeneration in the operated, upper, and lower adjacent segments were assessed using the Pfirrmann Classification. Postoperatively, a statistically significant difference was observed in visual analog scale and Oswestry Disability Index scores (p < 0.001). However, no statistically significant difference was seen in disc degeneration/regeneration and degeneration scores of the upper and lower adjacent segments between the preoperative and postoperative groups (p = 0.763, p = 0.518, p = 0.201). Notably, a positive effect on disc regeneration at the operated level (32.4%) was observed. No significant differences were found between the groups in terms of operation rates, screw loosening, and screw breakage after adjacent segment disease (p > 0.05). In patients without advanced degeneration, all three dynamic systems demonstrated the ability to prevent degeneration in the adjacent and operated segments while promoting regeneration in the operated segment. Beyond inhibiting abnormal movement in painful segments, maintaining physiological motion and providing axial distraction in the operated segment emerged as key mechanisms supporting regeneration.

Revision surgery for failure of the dynamic stabilization system of the lumbar spine

Revision surgery for failure of the dynamic stabilization system of the lumbar spine

Advanced dynamic stability system developed for nonlinear load

&lt;span lang="EN-US"&gt;The conventional production of electrical energy gives rise to environmental problems and involves high production costs. To cope with the increasing demand for electrical loads and to optimize power transmission on the grid, it is imperative to shift towards renewable energies and their hybrid utilization. This planning study assesses the impact of fluctuating electric loads on bus voltages and frequency, with the objective of distributing energy in a more efficient and dynamic manner. Moreover, we delve into the implementation of artificial intelligence (IAPS) to curtail operations, minimize losses (GED), optimize production plans (EMSO), and synchronize decentralized multi-machine power systems (MMSA). Our study scrutinizes power dispatching on dynamic models of purely consuming loads, which are subject to dynamic constraints, by utilizing educational software that encompasses 13 cycles for 24 hours of frequency studies for multisource production in a standardized electrical system (EPSS). The control outcomes obtained through validation on an IEEE30 bus network display a resilient model for planned productions.&lt;/span&gt;

STUDY OF THE PERFORMANCE OF THE DYNAMIC LEVEL STABILIZATION SYSTEM OPERATION IN THE WELLBORE EQUIPPED WITH AN ELECTRICAL SUBMERSIBLE PUMP UNIT

Link for citation: Totanov A.S., Molchanova V.A., Urazakov K.R. Study of the performance of the dynamic level stabilization system operation in the wellbore equipped with an electrical submersible pump unit. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 210-219. In Rus. The relevance of the study is related to the widespread use of electrical submersible pump units in the production of low-viscosity oils and water-gas-oil emulsions at this stage of development of mechanized production. However, the current production conditions associated with changing reservoir parameters bring to the fore a number of technical problems that need to be solved. One of these challenges is the phenomenon in which the dynamic level of the well decreases due to changes in reservoir parameters (reservoir pressure, productivity factor, etc.). Decrease of dynamic liquid level in the well leads to complications during operation of electrical submersible pump units. As a consequence, the increased cavitation in impellers is possible due to pressure reduction on the pump intake, and also full pump supply failure is not excluded at significant reduction of the dynamic level of the borehole fluid. In this relation, a technical solution, consisting in installation of bypass device (electrical valve) above the place of suspension of electrical submersible pump plant to maintain stable dynamic liquid level in the well and avoid complications during pump operation, was suggested. To confirm the feasibility of the dynamic level stabilization system, a mathematical model was developed to evaluate the effectiveness of complication prevention with the help of the proposed technical solution during the operation of the electric centrifugal pump unit. The main aim of the research is to develop a calculation method for studying the dynamics of the dynamic level stabilization system. Objects: an electrical submersible pump unit in conjunction with a system for stabilizing the dynamic level of the well. The influence of the diameter and length of the electrical valve on the efficiency of the dynamic level recovery was studied, taking into account hydraulic losses during the system operation. Methods. The research method is reduced to numerical solution of differential, linear and non-linear equations describing flow and pressure at electrical submersible pump unit outlet in steady-state mode, fluid flow through the electrical valve taking into account hydraulic resistances, flow of hydrodynamic processes in annular space during stabilization system operation, that is change of fluid level above the pump depending on borehole conditions and design parameters of electric valve. Results. Effect of parameters of the bypass valve – the diameter of flow section and length on dynamics of change of a liquid level above the pump, as well as the impact of liquid properties, namely its viscosity on intensity of restoration of a liquid level above the pump was studied. It was found that when the diameter of the electrical valve is increased, more intensive restoration of the liquid level above the pump is observed due to the reduction of hydraulic resistance in the valve cavity. Similarly, it was found that with increase of electrical valve length, as well as with increase of viscosity of liquid, coefficient of flow and intensity of liquid level recovery above the pump decreases respectively.

Interrater and Intrarater Reliability of the Intra-Abdominal Pressure Test in Young Adults

BACKGROUND: Diaphragm is not used correctly to its fullest potential which can lead to injury provoking compensations. If recruited properly, the diaphragm aids in the production of intra-abdominal pressure, which is necessary for core and spinal stabilization. Intra-abdominal pressure is a key component of our dynamic stability system. OBJECTIVE: The purpose of this study was to determine the interrater and intrarater reliability of the intra-abdominal pressure test in young adults. METHODOLOGY: It is a non-experimental design of test-retest type. 80 subjects (50 women and 30 men) aged 18-28 years with the BMI of &lt; 23.05-24.9 kg/m2 were conveniently included. Subjects with the history of low back pain for past 3 months, any hip or knee surgery for last 1 year, thoracic or thoracoabdominal surgery, postural deformities, cardiorespiratory diseases, pregnancy and pelvic floor dysfunction was excluded. The intra- abdominal pressure test had been carried to the subjects on the same day for the interrater reliability and 1 week later for the intrarater reliability. The signs of proper stabilization with the correct and incorrect activation of the chest and abdominal movements of the subjects were documented independently between the raters and scoring had been done. RESULTS: The results of the study showed an overall excellent interrater reliability of ICC=0.957 and intrarater reliability of ICC= 0.903 of the test. CONCLUSION: The study concludes that there is an overall excellent interrater and intrarater reliability of the intra-abdominal pressure test in normal young adults and hence it can be used in clinical practice. Keywords: Diaphragm, Intra-abdominal pressure, Intra-abdominal pressure test, Core stability, Spinal stability.

Radiological factors affecting functional outcome after the implantation of BDYN™ dynamic stabilization system for low-grade lumbar degenerative spondylolisthesis

BackgroundThe objectives of this study are to identify radiological factors associated with good functional outcomes after the implantation of BDYN™ dynamic stabilization system in the setting of painful low-grade degenerative lumbar spondylolisthesis (DLS). Material and methodsIn this monocentric, retrospective study, we followed 50 patients, a 5-years period, with chronic lower back pain, radiculopathy and/or neurogenic claudication evolving for at least one year that failed conservative treatment. All patients presented low-grade DLS and underwent lumbar dynamic stabilization. Radiological and clinical outcomes were assessed preoperatively and 24months after surgery. Functional evaluation was based on the Oswestry Disability Index (ODI), the Numerical Rating Scale (NRS), and the Walking Distance (WD). Radiological analysis was based on lumbar X-rays and MRI parameters. Patients were divided into two groups according to the reduction in the postoperative ODI score (more or less than 15 points), and statistical analysis was performed between both groups to find predictive radiological factors for a satisfying functional outcome. ResultsClinically, 80% (40 patients) had a satisfying functional result, and 20% (10 patients) were considered having a poor outcome according to the ODI score. Radiologically, the loss in segmental lordosis was statistically associated with bad functional outcomes (18° for ODI decrease>15 versus 11° for ODI decrease<15). There is also a tendency showing that a higher Pfirmann disc signal grade (grade IV) and a severe canal stenosis according to Schizas classification (grade C & D) are predictive of a poor clinical result, but that must be confirmed in future studies. ConclusionsBDYN™ appears safe and well-tolerated. This new device should be effective for the treatment of patients with low-grade DLS. It provides significant improvement in terms of daily life activity and pain. Moreover, we have been able to deduce that a kyphotic disc is associated with a bad functional outcome after BDYN™ device implantation. It may represent a contraindication for the implantation of such DS device. Moreover, it seems that it is better to implant BDYN™ in DLS with mild or moderate disc degeneration and canal stenosis.

Adjacent Segment Disease

Spinal fusion is gold-standard treatment for degenerative disc disease (DDD) both at cervical and lumbar spine, and it is time tested. Perhaps it has its bundle of complications. Elimination of motion results in accentuated degeneration of adjacent segments leading to adjacent segment degeneration radiographically and, if symptomatic, leads to adjacent segment disease. There is still a debate on whether there is such an entity or whether it is a manifestation of natural history or an iatrogenic phenomenon. Motion preservation surgeries were developed to address the same issue, which includes total disc replacement, nucleus replacement, interspinous implants, and dynamic posterior stabilization systems. The primary goal of motion preservation surgery is to maintain normal or near-normal motion in an attempt to prevent adverse outcomes, which are commonly seen with conventional spinal fusion, most notably the development of adjacent-level DDD. A search was conducted in PubMed using the terms (“adjacent segment”) AND (“disease” OR “degeneration” or “pathology”). Then the articles were shortlisted based on time of publication (2005 onward), publication in English and inclusion of human subjects. This resulted in 253 articles. Another search for ((“Motion preservation”) AND (“Spine”)) OR (“Adjacent segment disease”) OR (“Adjacent segment pathology”) OR (“Adjacent segment degeneration”) yielded 76 articles. This narrative review discusses various issues pertaining to the current evidence regarding adjacent segment disease (ASD), including the controversy on whether ASD is actually an entity, its etiopathogenesis, clinical features, as well as the role of motion preservation technologies to reduce its incidence. There is still enthusiasm and concerns regarding the benefits of motion preservation surgery since it is still an area of ongoing research.

Biomechanical Effect of Hybrid Dynamic Stabilization Implant on the Segmental Motion and Intradiscal Pressure in Human Lumbar Spine.

The hybrid dynamic stabilization system, Dynesys-Transition-Optima, represents a novel pedicle-based construct for the treatment of lumbar degenerative disease. The theoretical advantage of this system is to stabilize the treated segment and preserve the range of motion within the adjacent segment while potentially decreasing the risk of adjacent segment disease following lumbar arthrodesis. Satisfactory short-term outcomes were previously demonstrated in the Dynesys-Transition-Optima system. However, long-term follow-up reported accelerated degeneration of adjacent segments and segmental instability above the fusion level. This study investigated the biomechanical effects of the Dynesys-Transition-Optima system on segment motion and intradiscal pressure at adjacent and implanted levels. Segmental range of motion and intradiscal pressure were evaluated under the conditions of the intact spine, with a static fixator at L4-5, and implanted with DTO at L3-4 (Dynesys fixator) and L4-5 (static fixator) by applying the loading conditions of flexion/extension (±7.5 Nm) and lateral bending (±7.5 Nm), with/without a follower preload of 500 N. Our results showed that the hybrid Dynesys-Transition-Optima system can significantly reduce the ROM at the fusion level (L4-L5), whereas the range of motion at the adjacent level (L3-4) significantly increased. The increase in physiological loading could be an important factor in the increment of IDP at the intervertebral discs at the lumbar spine. The Dynesys-Transition-Optima system can preserve the mobility of the stabilized segments with a lesser range of motion on the transition segment; it may help to prevent the occurrence of adjacent segment degeneration. However, the current study cannot cover all the issues of adjacent segmental diseases. Future investigations of large-scale and long-term follow-ups are needed.

Finite element analysis after rod fracture of the spinal hybrid elastic rod system

BackgroundThe spinal hybrid elastic (SHE) rod dynamic stabilization system can provide sufficient spine support and less adjacent segment stress. This study aimed to investigate the biomechanical effects after the internal fracture of SHE rods using finite element analysis.MethodsA three-dimensional nonlinear finite element model was developed. The SHE rod comprises an inner nitinol stick (NS) and an outer polycarbonate urethane (PCU) shell (PS). The fracture was set at the caudal third portion of the NS, where the maximum stress occurred. The resultant intervertebral range of motion (ROM), intervertebral disc stress, facet joint contact force, screw stress, NS stress, and PCU stress were analyzed.ResultsWhen compared with the intact spine model, the overall trend was that the ROM, intervertebral disc stress, and facet joint force decreased in the implanted level and increased in the adjacent level. When compared with the Ns-I, the trend in the Ns-F decreased and remained nearly half effect. Except for torsion, the PS stress of the Ns-F increased because of the sharing of NS stress after the NS fracture.ConclusionsThe study concluded the biomechanical effects still afford nearly sufficient spine support and gentle adjacent segment stress after rod fracture in a worst-case scenario of the thinnest PS of the SHE rod system.

Biomechanical comparison of the femoral neck system versus InterTan nail and three cannulated screws for unstable Pauwels type III femoral neck fracture

BackgroundThere are a variety of internal fixation methods for unstable femoral neck fractures (FNFs), but the best method is still unclear. Femoral neck system (FNS) is a dynamic angular stabilization system with cross screws, and is a new internal fixation implant designed for minimally invasive fixation of FNFs. In this study, we conducted a biomechanical comparison of FNS, InterTan nail and three cannulated screws for the treatment of Pauwels III FNFs and investigate the biomechanical properties of FNS.MethodsA total of 18 left artificial femurs were selected and randomly divide into Group A (fixation with FNS), Group B (fixation with InterTan nail) and Group C (fixation with three cannulated screws), with 6 specimens in each group. After creating Pauwels type III FNF models, the specimens in each were tested with non-destructive quasi-static tests, including torsion, A-P bending and axial compression tests. The average slope of the linear load–deformation curve obtained from quasi-static tests defines the initial torsional stiffness, A-P bending stiffness, and axial compression stiffness. After cyclic loading test was applied, the overall deformation of models and local deformation of implant holes in each group were assessed. The overall deformation was estimated as the displacement recorded by the software of the mechanical testing apparatus. Local deformation was defined as interfragmental displacement. Data were analyzed by one-way analysis of variance (ANOVA) followed by Bonferroni post hoc test using the SPSS software (version 24.0, IBM, New York, NY, USA). Correlation analysis was performed using Pearson’s correlation analysis.ResultsGroup B exhibited significantly higher axial stiffness and A-P bending stiffness than the other two groups (P < 0.01), while Group A had significantly higher axial stiffness and A-P bending stiffness than Group C (P < 0.01). Groups A and B exhibited significantly higher torsional stiffness than Group C (P < 0.01), no statistical significance was observed between Groups A and B (P > 0.05). Group B exhibited significantly lower overall and local deformations than the other two groups (P < 0.01), while Group A had significantly lower overall and local deformations than Group C (P < 0.01). Correlation analysis revealed positive correlation between axial stiffness and A-P bending stiffness (r = 0.925, P < 0.01), torsional stiffness (r = 0.727, P < 0.01), between torsional stiffness and A-P bending stiffness; negative correlation between overall, local deformations and axial stiffness (r = − 0.889, − 0.901, respectively, both P < 0.01), and positive correlation between the two deformations (r = − 0.978, P < 0.01).ConclusionFor fixation of unstable FNFs, InterTan nail showed the highest axial stiffness and A-P bending stiffness, followed by FNS, and then three cannulated screws. Torsional stiffness of FNS was comparable to that of the InterTan nail. FNS, as a novel minimally invasive implant, can create good mechanical environment for the healing of unstable FNFs. Clinical studies are needed to confirm the potential advantages of FNS observed in this biomechanical study.

Percutaneously placed lumbar interspinous stabilization devices - a review of current clinical research.

There are generally two categories of interspinous stabilization devices widely used in clinics: (1) Static spacing systems, such as X-STOP, Wallis. (2) Dynamic stabilization systems, such as Coflex, DIAM, stenofix. However, with the advancement of minimally invasive techniques, interspinous stabilization devices paced through percutaneous minimally invasive approach have been invented and applied in daily clinic. Its advantages, such as simple operation, small trauma and short hospitalization time are gradually recognized by doctors and patients. Percutaneous minimally invasive approach will become the future direction in the field of interspinous stabilization devices. This paper therefore reviewed the current clinical research progress of interspinous stabilization devices performed under percutaneous minimally invasive approach. We searched studies related to percutaneously placed lumbar interspinous stabilization devices from PubMed, since January 1, 2007. The main types and characteristics of currently used and percutaneously placed interspinous stabilization devices were summarized. Meanwhile, clinical studies relevant to currently used and percutaneously placed interspinous stabilization devices were also summarized. The future of interspinous stabilization devices is bright, we would like to see more advanced and newly invented percutaneously placed interspinous stabilization devices, meanwhile, it is fundamentally crucial to enroll more clinical studies with long-term follow-up to determine the best indications for each device therefore to achieve more satisfactory clinical outcomes.

The Effects of Cord Pretension and Spacer Length in Dynamic Neutralization Stabilization System (Dynesys): In Vitro Experiment

The Effects of Cord Pretension and Spacer Length in Dynamic Neutralization Stabilization System (Dynesys): In Vitro Experiment

Assessment of outcome of posterior dynamic stabilization system in degenerative lumbar disease

Background: Degenerative disc disease is a leading cause of chronic back pain in the aging population in the world. The present study was conducted to assess outcome of posterior dynamic stabilization system in degenerative lumbar diseases. Materials &amp; Methods: 78 patients of degenerative lumbar diseases of both genders were divided into 2 groups of 39 each. Group I patients underwent decompression and implantation of Dynesys and group II patients underwent PLIF. ODI, VAS scores for back pain and leg pain, operation time, blood loss, and complications were compared in both groups. Results: There were 25 males and 14 females in group I and 20 males and 19 females in group II. The operative time (min) was 136.2 in group I and 172.4 in group II. Blood loss (ml) was 362.4 in group I and 438.2 in group II. Complications were dural tear seen 2 in group II, wound infection was seen in 1 in group II, screw loosening was 1 in group I and 2 in group II and back &amp; leg pain seen 3 in group I and 4 in group II. The mean ODI was 32.5 and 38.5, VAS back pain was 2.6 and 3.12.

Dynamization-Posterior Lumbar Interbody Fusion for Hemodialysis-Related Spondyloarthropathy: Evaluation of the Radiographic Outcomes and Reoperation Rate within 2 Years Postoperatively.

Clinical case series. This study aimed to report dynamization-posterior lumbar interbody fusion (PLIF), our surgical treatment for hemodialysisrelated spondyloarthropathy (HSA), and investigate patients' postoperative course within 2 years. HSA often requires lumbar fusion surgery. Conventional PLIF for HSA may cause progressive destructive changes in the vertebral endplate, leading to progressive cage subsidence, pedicle screw loosening, and pseudoarthrosis. A dynamic stabilization system might be effective in patients with a poor bone quality. Thus, we performed "dynamization-PLIF" in hemodialysis patients with destructive vertebral endplate changes. We retrospectively examined patients with HSA who underwent dynamization-PLIF at our hospital between April 2010 and March 2018. The radiographic measurements included lumbar lordosis and local lordosis in the fused segment. The evaluation points were before surgery, immediately after surgery, 1 year after surgery, and 2 years after surgery. The preoperative and postoperative radiographic findings were compared using a paired t-test. A p-value of less than 0.05 was considered significant. We included 50 patients (28 males, 22 females). Lumbar lordosis and local lordosis were significantly improved through dynamization- PLIF (lumbar lordosis, 28.4°-35.5°; local lordosis, 2.7°-12.8°; p<0.01). The mean local lordosis was maintained throughout the postoperative course at 1- and 2-year follow-up (12.9°-12.8°, p=0.89 and 12.9°-11.8°, p=0.07, respectively). Solid fusion was achieved in 59 (89%) of 66 fused segments. Solid fusion of all fixed segments was achieved in 42 cases (84%). Within 2 years postoperatively, only six cases (12%) were reoperated (two, surgical debridement for surgical site infection; two, reoperation for pedicle screw loosening; one, laminectomy for epidural hematoma; one, additional fusion for adjacent segment disease). Dynamization-PLIF showed local lordosis improvement, a high solid fusion rate, and a low reoperation rate within 2 years of follow-up.