Applications In Spinal Surgery Research Articles

Biomimetic Porous Ti6Al4V Implants: A Novel Interbody Fusion Cage via Gel-Casting Technique to Promote Spine Fusion.

An interbody fusion cage (Cage) is crucial in spinal decompression and fusion procedures for restoring normal vertebral curvature and rebuilding spinal stability. Currently, these Cages suffer from issues related to mismatched elastic modulus and insufficient bone integration capability. Therefore, a gel-casting technique is utilized to fabricate a biomimetic porous titanium alloy material from Ti6Al4V powder. The biomimetic porous Ti6Al4V is compared with polyetheretherketone (PEEK) and 3D-printed Ti6Al4V materials and their respective Cages. Systematic validation is performed through mechanical testing, in vitro cell, in vivo rabbit bone defect implantation, and ovine anterior cervical discectomy and fusion experiments to evaluate the mechanical and biological performance of the materials. Although all three materials demonstrate good biocompatibility and osseointegration properties, the biomimetic porous Ti6Al4V, with its excellent mechanical properties and a structure closely resembling bone trabecular tissue, exhibited superior bone ingrowth and osseointegration performance. Compared to the PEEK and 3D-printed Ti6Al4V Cages, the biomimetic porous Ti6Al4V Cage outperforms in terms of intervertebral fusion performance, achieving excellent intervertebral fusion without the need for bone grafting, thereby enhancing cervical vertebra stability. This biomimetic porous Ti6Al4V Cage offers cost-effectiveness, presenting significant potential for clinical applications in spinal surgery.

Multimodal Deep Learning-based Radiomics Approach for Predicting Surgical Outcomes in Patients with Cervical Ossification of the Posterior Longitudinal Ligament.

A retrospective analysis. This research sought to develop a predictive model for surgical outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) using deep learning and machine learning (ML) techniques. Determining surgical outcomes assists surgeons in communicating prognosis to patients and setting their expectations. Deep learning and ML are computational models that identify patterns from large datasets and make predictions. Of the 482 patients, 288 patients were included in the analysis. A minimal clinically important difference (MCID) was defined as gain in Japanese Orthopaedic Association (JOA) score of 2.5 points or more. The predictive model for MCID achievement at 1 year post-surgery was constructed using patient background, clinical symptoms, and preoperative imaging features (x-ray, CT, MRI) analyzed via LightGBM and deep learning with RadImagenet. The median preoperative JOA score was 11.0 (IQR: 9.0-12.0), which significantly improved to 14.0 (IQR: 12.0-15.0) at 1 year after surgery (P < 0.001, Wilcoxon signed-rank test). The average improvement rate of the JOA score was 44.7%, and 60.1% of patients achieved the MCID. Our model exhibited an area under the receiver operating characteristic curve of 0.81 and the accuracy of 71.9% in predicting MCID at 1 year. Preoperative JOA score and certain preoperative imaging features were identified as the most significant factors in the predictive models. A predictive ML and deep learning model for surgical outcomes in OPLL patients is feasible, suggesting promising applications in spinal surgery. 4.

Trends in navigation-handheld systems

Navigation-assisted surgical procedures in orthopedics and trauma surgery have become increasingly widespread over the last 20years. In addition to applications in spinal surgery, they are primarily available for knee and hip endoprosthetics. On the one hand, computer-assisted procedures have been increasingly expanded with robotic assistance systems in recent years, and on the other hand, so-called handheld navigation systems have been developed, which enable specialized use directly in the operating field at lower acquisition costs. The aim of this overview is to describe current handheld systems and to present the respective technical principles and the available scientific results. Three handheld systems for TKA use, two for THA use and one system to support pedicle screw placement on the spine are presented.

Effect of Intra-Wound Vancomycin Application in Spinal Surgery on the Incidence of Postoperative Surgical Site Infection—A Meta-Analysis

Effect of Intra-Wound Vancomycin Application in Spinal Surgery on the Incidence of Postoperative Surgical Site Infection—A Meta-Analysis

Development and Evaluation of Thrombin-Loaded Gelatin Hemostatic Sheets for Spinal Surgery Applications

Development and Evaluation of Thrombin-Loaded Gelatin Hemostatic Sheets for Spinal Surgery Applications

Tranexamic acid-induced focal convulsions after spinal surgery: a rare case report and literature review on side effects of accidental spinal administration of tranexamic acid.

Convulsions are a neurological illness that has complexity. In clinical treatment, drug-induced convulsions appear from time to time. Drug-induced convulsions often begin as isolated acute seizures but may progress to persistent seizures. In orthopedics, topical administration of tranexamic acid is commonly used in conjunction with intravenous drip to achieve hemostasis during artificial joint replacement surgery. However, side effects induced by tranexamic acid accidental spinal administration should be taken seriously. We report a case of a middle-aged male treated with tranexamic acid locally in combination with intravenous drip for intraoperative hemostasis when undergoing spinal surgery. The patient had involuntary convulsions in both lower limbs after the operation. After symptomatic administration, the symptoms of convulsions gradually resolved. During the follow-up, the convulsions never occurred again. We reviewed the literature on cases with side effects of local tranexamic acid application in spinal surgery and discussed the mechanism of tranexamic acid-induced convulsions. Tranexamic acid is associated with an increased incidence of postoperative seizures. However, many clinicians are unaware that tranexamic acid causes seizures. This rare case summarized the risk factors and clinical features of these seizures. Moreover, it highlights several clinical and preclinical studies that offer mechanistic insights into the potential causes and treatments for tranexamic acid-associated seizures. A clear understanding of tranexamic acid-induced convulsions-related adverse reactions can help the first-line clinical screening of causes and adjustment of drug treatment. This review will aid the medical community by increasing awareness about tranexamic acid-associated seizures and translating scientific findings into therapeutic interventions for patients.

Systematic Review: Applications of Intraoperative Ultrasonography in Spinal Surgery

As a result of increased practicality and decreased costs and radiation, interest has increased in intraoperative ultrasonography (iUS) in spinal surgery applications; however, few studies have provided a robust overview of its use in spinal surgery. We synthesize findings of existing literature on use of iUS in navigation, pedicle screw placement, and identification of anatomy during spinal interventions. PRISMA guidelines were used in this systematic review. Studies were identified through PubMed, Scopus, and Google Scholar databases using the search string. Abstracts mentioning iUS in spine applications were included. On full-text review, exclusion criteria were implemented, including outdated studies or those with weak topic relevance or statistical power. On elimination of duplicates, multireviewer screening for eligibility, and citation search, 44 articles were analyzed. Navigation using iUS is safe, effective, and economical. iUS registration accuracy and success are within clinically acceptable limits for image-guided navigation. Pedicle screw instrumentation with iUS is precise, with a favorable safety profile. Anatomic landmarks are reliably identified with iUS, and surgeons are overwhelmingly successful in neural or vascular tissue identification with iUS modalities, including standard B mode, Doppler, and contrast-enhanced ultrasonography. iUS use in traumatic reduction of fractures properly identifies anatomic structures, intervertebral disc space, and vasculature. iUS eliminates radiation, decreases costs, and provides sufficient accuracy and reliability in identification of anatomic and neurovascular structures in various spinal surgery settings.

Pulsed Electromagnetic Field Stimulators Efficacy for Noninvasive Bone Growth in Spine Surgery.

The growth of pulsed electromagnetic field (PEMF) therapy and its progress over the years for use in post-operative bone growth has been revolutionary in its effect on bone tissue proliferation and vascular flow. However, further progress in PEMF therapy has been difficult due to lack of more evidence-based understanding of its mechanism of action. Our objective was to review the current understanding of bone growth physiology, the mechanism of PEMF therapy action along with its application in spinal surgery and associated outcomes. The authors of this review examined multiple controlled, comparative, and cohort studies to compare fusion rates of patients undergoing PEMF stimulation. Examining spinal fusion rates, a rounded comparison of post-fusion outcomes with and without bone stimulator was performed. Results showed that postoperative spinal surgery PEMF stimulation had higher rates of fusion than control groups. Though PEMF therapy was proven more effective, multiple factors contributed to difficulty in patient compliance for use. Extended timeframe of treatment and cost of treatment were the main obstacles to full compliance. This review showed that PEMF therapy presented an increased rate of recovery in patients, supporting the use of these devices as an effective post-surgical aid. Given the recent advances in the development of PEMF devices, affordability and access will be much easier suited to the patient population, allowing for more readily available treatment options.

Multi-view 3D skin feature recognition and localization for patient tracking in spinal surgery applications

BackgroundMinimally invasive spine surgery is dependent on accurate navigation. Computer-assisted navigation is increasingly used in minimally invasive surgery (MIS), but current solutions require the use of reference markers in the surgical field for both patient and instruments tracking.PurposeTo improve reliability and facilitate clinical workflow, this study proposes a new marker-free tracking framework based on skin feature recognition.MethodsMaximally Stable Extremal Regions (MSER) and Speeded Up Robust Feature (SURF) algorithms are applied for skin feature detection. The proposed tracking framework is based on a multi-camera setup for obtaining multi-view acquisitions of the surgical area. Features can then be accurately detected using MSER and SURF and afterward localized by triangulation. The triangulation error is used for assessing the localization quality in 3D.ResultsThe framework was tested on a cadaver dataset and in eight clinical cases. The detected features for the entire patient datasets were found to have an overall triangulation error of 0.207 mm for MSER and 0.204 mm for SURF. The localization accuracy was compared to a system with conventional markers, serving as a ground truth. An average accuracy of 0.627 and 0.622 mm was achieved for MSER and SURF, respectively.ConclusionsThis study demonstrates that skin feature localization for patient tracking in a surgical setting is feasible. The technology shows promising results in terms of detected features and localization accuracy. In the future, the framework may be further improved by exploiting extended feature processing using modern optical imaging techniques for clinical applications where patient tracking is crucial.

Effect of intrawound vancomycin application in spinal surgery on the incidence of surgical site infection: a meta-analysis.

BackgroundDespite great advances in aseptic surgical techniques, surgical site infection (SSI) is still one of the main complications after spine surgery. SSI can bring tremendous physical, psychological, and economic challenges to patients. Intrawound vancomycin application is a much disputed method for the prevention of SSI after spine surgery.ObjectiveThe aim of this study is to review the current literature for studies on the intra-wound application of vancomycin powder and to analyze its effectiveness in the prevention of postoperative SSI.MethodsPubMed, Medline, Elsevier, and CNKI were searched for the key words “vancomycin”, “local/intraoperative/topical/intra-wound”, “spine/spinal/lumbar/cervical/thoracolumbar surgery”, “infection”, and “SSI” in published studies on the effectiveness of intrawound vancomycin application to prevent postoperative SSI. RevMan 5.3 was used to compare the data extracted from the studies included.ResultsA total of 27 studies involving 17,321 patients were included in the final analysis. Among those patients, 7,423 patients were treated with vancomycin to prevent SSI, with 9,898 in control groups. SSI incidence after surgery in experimental groups was 0.39 times as high as control groups, and this difference was statistically significant (P<0.01). Among patients who underwent internal fixation, vancomycin application significantly reduced the incidence of postoperative SSI (OR 0.31 95% CI 0.19–0.50; P<0.01). Meanwhile, vancomycin did not affect SSI incidence in patients who did not receive internal fixation (P=0.17) or received deformity correction (P=0.25).ConclusionSSI incidence after spinal surgery can be significantly reduced by intrawound application of vancomycin in most circumstances. This method can be applied in various spinal procedures involving instrumentation to prevent postoperative SSI.

Are Controversial Issues in Cervical Total Disc Replacement Resolved or Unresolved?: A Review of Literature and Recent Updates.

Since the launch of cervical total disc replacement (CTDR) in the early 2000s, many clinical studies have reported better outcomes of CTDR compared to those of anterior cervical discectomy and fusion. However, CTDR is still a new and innovative procedure with limited indications for clinical application in spinal surgery, particularly, for young patients presenting with soft disc herniation with radiculopathy and/or myelopathy. In addition, some controversial issues related to the assessment of clinical outcomes of CTDR remain unresolved. These issues, including surgical outcomes, adjacent segment degeneration (ASD), heterotopic ossification (HO), wear debris and tissue reaction, and multilevel total disc replacement (TDR) and hybrid surgeries are a common concern of spine surgeons and need to be resolved. Among them, the effect of CTDR on patient outcomes and ASD is theoretically and clinically important; however, this issue remains disputable. Additionally, HO, wear debris, multilevel TDR, and hybrid surgery tend to favor CTDR in terms of their effects on outcomes, but the potential of these factors for jeopardizing patients' safety postoperatively and/or to exert harmful effects on surgical outcomes in longer-term follow-up cannot be ignored. Consequently, it is too early to determine the therapeutic efficacy and cost-effectiveness of CTDR and will require considerable time and studies to provide appropriate answers regarding the same. For these reasons, CTDR requires longer-term follow-up data.

Bioinert Ceramics: State-of-the-Art

Bioinert ceramics in use today are the result of more than 60 years of continuous development. Early studies were concentrated on alumina that in the late 1960s was the most advanced ceramic, and on pyrolytic carbon. After tests in orthopedic bearings, pyrolytic carbon found clinical applications in artificial heart valves, where it is in clinical use so far. After 1970 zirconia-toughened ceramics (YTZP, ZTA, ATZ) were investigated in view of their use as biomaterials in orthopedics. Especially the introduction of YTZP in clinics in the 1990s gave a new momentum to the use of inert bioceramics. So far, zirconia-toughened ceramics are replacing alumina because of their outstanding mechanical properties leading to high reliability in ceramic components. The behavior of ZTAs and ATZs are exploited in several innovative devices. Especially metal-free devices are of interest, because of the increasing number of patients sensitized to metals. Using zirconia-toughened ceramics were achieved remarkable development in ceramic knee replacements, a field pioneered by Japanese researchers, because the behavior of these materials allow the production of devices similar in size to the metallic ones. In dentistry, a number of manufacturers are marketing metal-free dental implants, as well as machinable zirconia blanks for the production of crowns, bridges, copings by CAD/CAM. Besides oxides, that in todays’ orthopedics and dentistry are the state-of-the-art bioinert ceramics, silicon nitride has found application in spinal surgery, and investigations in view of its use in joint replacement bearings are in progress.

Optimized decellularization protocol including \u03b1-Gal epitope reduction for fabrication of an acellular porcine annulus fibrosus scaffold

Recent advances in tissue engineering have led to potential new strategies, especially decellularization protocols from natural tissues, for the repair, replacement, and regeneration of intervertebral discs. This study aimed to validate our previously reported method for the decellularization of annulus fibrosus (AF) tissue and to quantify potentially antigenic α-Gal epitopes in the decellularized tissue. Porcine AF tissue was decellularized using different freeze–thaw temperatures, chemical detergents, and incubation times in order to determine the optimal method for cell removal. The integrity of the decellularized material was determined using biochemical and mechanical tests. The α-Gal epitope was quantified before and after decellularization. Decellularization with freeze–thaw in liquid nitrogen, an ionic detergent (0.1% SDS), and a 24 h incubation period yielded the greatest retention of GAG and collagen relative to DNA reduction when tested as single variables. Combined, these optimal decellularization conditions preserved more GAG while removing the same amount of DNA as the conditions used in our previous study. Components and biomechanical properties of the AF matrix were retained. The decellularized AF scaffold exhibited suitable immune-compatibility, as evidenced by successful in vivo remodeling and a decrease in the α-Gal epitope. Our study defined the optimal conditions for decellularization of porcine AF tissues while preserving the biological composition and mechanical properties of the scaffold. Under these conditions, immunocompatibility was evidenced by successful in vivo remodeling and reduction of the α-Gal epitope in the decellularized material. Decellularized AF scaffolds are potential candidates for clinical applications in spinal surgery.

The Effect of Vancomycin and Gentamicin Antibiotics on Human Osteoblast Proliferation, Metabolic Function, and Bone Mineralization.

The present study investigates the effect of vancomycin and gentamicin antibiotics on primary human osteoblasts. Osteoblasts were incubated with vancomycin, gentamicin, or with povidone-iodine (PVI), at concentrations advocated for wound irrigation. Osteoblast proliferation, metabolic function, and bone mineralization were measured. The aim of the study was to model gentamicin and vancomycin wound irrigation in vitro and to examine the effect on osteoblast viability and cellular function in comparison to 0.35% PVI. Vancomycin, gentamicin, and dilute PVI are employed as wound irrigants in spinal surgery to reduce infection. We have, however, recently demonstrated that 0.35% PVI has a detrimental effect on osteoblast cellular function and bone mineralization. Studies to determine the effects of antibiotic wound irrigation solutions on osteoblasts and bone mineralization are therefore warranted. Primary human osteoblasts were exposed for 20 minutes to phosphate buffered saline (PBS) control, vancomycin (35 or 3.5 mmol/L), gentamicin (34 or 3.4 mmol/L), or 0.35% PVI for 3 minutes. Cellular proliferation was measured during 7 days by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Osteoblast metabolic function was determined using a Seahorse XFe24 Bioanalyzer. Mineralized bone nodules were quantified using Alizarin red. At concentrations advocated for wound irrigation, both gentamicin (3.4 mmol/L) and vancomycin (3.5 mmol/L) induced a transient 15% to 20% reduction in osteoblast proliferation, which returned to control values within 72 hours. This was in marked contrast to the effect of 0.35% PVI, which resulted in a sustained reduction in osteoblast proliferation of between 40% and 50% during 7 days. Neither gentamicin nor vancomycin at concentrations up to 10× clinical dose had any effect on osteoblast oxygen consumption rate, or significantly affected mineralized bone nodule formation. Vancomycin and gentamicin solutions, at concentrations advocated for intrawound application in spinal surgery, have a small but transient effect on osteoblast proliferation, and no effect on either osteoblast metabolic function or bone nodule mineralization. N/A.

Evaluation of Titanium-Coated Pedicle Screws: In Vivo Porcine Lumbar Spine Model

Many studies have addressed the problem of loosening pedicle screws in spinal surgery, which is a serious concern. Titanium coating of medical implants (arthroplasty) is common, but few studies involving invivo spine models have been reported. We evaluated the radiological, mechanical, and histological characteristics of titanium-coated pedicle screws compared with uncoated or hydroxyapatite-coated pedicle screws. Three different types of pedicle screws, i.e., uncoated, hydroxyapatite-coated, and titanium-coated, were implanted into the lumbar 3-4-5 levels of 9 mature miniature pigs. Radiological evaluation of loosening of pedicle screws was performed. Peak torsional extraction torque was tested in the 42 screws from 7 miniature pigs at 12 weeks postoperatively. The implant-bone interface of the remaining 12 pedicle screws from 2 miniature pigs in each group was assessed by micro-computed tomography and histologic studies. The incidence of loosening at 12 weeks postoperatively was not significantly different between the titanium-coated pedicle screw group and the other groups. The titanium-coated pedicle screw group exhibited the greatest mean extraction torsional peak torque at 12 weeks postoperatively (P < 0.05). Quantitative micro-computed tomography data were greatest in the titanium-coated pedicle screw group (P < 0.05). Histologic findings showed osteointegration with densely packed new bone formation at the screw coating-bone interface in the titanium-coated pedicle screw group. Fixation strength was greatest in the titanium-coated pedicle screw group. Osteointegration at the interface between the titanium-coated implant and bone produced prominent and firm bonding. The titanium-coated pedicle screw is a promising device for application in spinal surgery.

Basic science of mesenchymal stem cells in spine surgery

Current research is trending toward tissue engineering and regeneration of mesenchymal tissues in treatment of disease, particularly degenerative musculoskeletal pathology. Mesenchymal stem cells (MSCs) provide a potential option for improving bone and cartilage growth and repair based on their underlying potency. MSCs are attractive for their multipotent and immunological properties and ease of bulk manufacturing. This article reviews the basic science of MSCs and obstacles to clinical use and discusses the potential application in spinal surgery.

Fabrication and properties of acellular porcine anulus fibrosus for tissue engineering in spine surgery.

BackgroundOver the last few years, new treatments for a damaged intervertebral disc (IVD) have included strategies to repair, replace, or regenerate the degenerative disc. However, these techniques are likely to have limited success, due to insufficiently effective means to address the damaged anulus fibrosus (AF). Here, we try to develop a bioprocess method for decellularization of the xenogeneic AF tissue, with a view to developing a scaffold as a potential candidate for clinical application in spinal surgery.MethodsPorcine AFs were decellularized using freeze-thaw cycles, followed by various combined treatments with 0.1% sodium dodecyl sulfate (SDS) and nucleases.ResultsHematoxylin and eosin (H & E) staining showed that decellularization was achieved through the decellularization protocols. Biochemical analyses revealed 86% reduction in DNA, but only 15.9% reduction in glycosaminoglycan (GAG) content, with no significant difference in the hydroxyproline content. There was no appreciable cytotoxicity of the acellular AF. Biomechanical testing of the acellular AF found no significant decline in stiffness or Young’s modulus.ConclusionsPorcine AF tissues were effectively decellularized with the preservation of biologic composition and mechanical properties. These results demonstrate that acellular AF scaffolds would be a potential candidate for clinical application in spinal surgery.

Spinal Fusion in the Next Generation: Gene and Cell Therapy Approaches

Bone fusion represents a challenge in the orthopedics practice, being especially indicated for spine disorders. Spinal fusion can be defined as the bony union between two vertebral bodies obtained through the surgical introduction of an osteoconductive, osteoinductive, and osteogenic compound. Autogenous bone graft provides all these three qualities and is considered the gold standard. However, a high morbidity is associated with the harvest procedure. Intensive research efforts have been spent during the last decades to develop new approaches and technologies for successful spine fusion. In recent years, cell and gene therapies have attracted great interest from the scientific community. The improved knowledge of both mesenchymal stem cell biology and osteogenic molecules allowed their use in regenerative medicine, representing attractive approaches to achieve bone regeneration also in spinal surgery applications. In this review we aim to describe the developing gene- and cell-based bone regenerative approaches as promising future trends in spine fusion.

Intraoperative PEEP-ventilation during PMMA-injection for augmented pedicle screws: improvement of leakage rate in spinal surgery.

Within the last two decades the use of polymethylmethacrylate (PMMA) in the treatment of osteoporotic vertebral fractures has been established widely. Several techniques of cement application in spinal surgery have been described. Besides classical vertebroplasty, kyphoplasty and related techniques that reinforce stability of the fractured vertebral body itself, augmentation of pedicle screws became an issue in the past 10years. Aim of this technique is strengthening of the implant-bone-interface and the prevention of loosening and failure of posterior instrumentation in limited bone quality due to osteoporosis. PMMAuse in spinal surgery always bears the risk of cement leakage and cement embolism. There are only few publications dealing with cement leakage in pedicle screw augmentation. We examined our cohort concerning incidence and type of leakage in comparison to the literature. In particular, we evaluated a possible role of intrathoracic pressure during cementation procedure. In this retrospective study 42 patients were included. Mean age was 74 (57-89) years. 311 fenestrated, augmented screws were analyzed postoperatively concerning leakage and subsequent pulmonary embolism of cement particles. Overall, there was a leakage rate of 38.3%, and 28.6% of patients showed pulmonary embolism of PMMA. During surgery, patients were in part ventilated with a positive end-expiratory pressure (PEEP) of 15cmH2O during cement injection. These individuals showed significantly less leakage locally as well as less PMMA-emboli in the pulmonary circulation in contrast to patients ventilated without increased PEEP. PEEP elevation during administration of PMMA via fenestrated pedicle screws is reducing the leakage rate in spinal surgery. These beneficial effects warrant further evaluation in prospective studies.

A Practical Laboratory Study Simulating the Lumbar Microdiscectomy: Training Model in Fresh Cadaveric Sheep Spine

Laboratory training models are essential for developing and refining surgical skills prior to clinical application of spinal surgery. A simple simulation model is needed for young residents to learn how to handle instruments and to perform safe lumbar approaches. Our aim is to present a practical laboratory model using a fresh sheep lumbar spine that allows to simulate lumbar microdiscectomy in humans. The material consists of a fresh cadaveric spine from a 2-year-old sheep. The surgical steps for lumbar microdiscectomy were conducted under the magnification of the operating microscope. The cadaveric sheep spine represents a useful model to train posterior lumbar microdiscectomy.