Stability Of Vertebral Body Research Articles

Piezo1 involves in intracellular osteogenic transformation signal to promote the ossification of ligamentum flavum

Ectopic osteogenesis refers to the occurrence of osteoblasts in soft tissues other than bone tissue and the formation of bone tissue. The ligamentum flavum is an essential connecting structure between adjacent vertebral lamina, which participates in the formation of the vertebral canal's posterior wall and maintains the vertebral body's stability. Ossification of the ligamentum flavum (OLF) is one of the manifestations of systemic ossification of the spinal ligaments and one of the degenerative diseases related to the spine. However, there is a lack of research on the expression and biological function of Piezo1 in ligamentum flavum. Whether Piezo1 participates in the development of OLF is still unclear. The FX-5000C cell or tissue pressure culture and real-time observation and analysis system was applied to stretch ligamentum flavum cells to detect the expression of mechanical stress channel and osteogenic markers after the effect of different stretching durations. The results showed elevated expression of mechanical stress channel Piezo1 and osteogenic markers with the effect of tensile time duration. In conclusion, Piezo1 involves in intracellular osteogenic transformation signal to promote the ossification of ligamentum flavum. An approved explanatory model and further research will be required in the future.

Chapter 20 - Vertebral augmentation

Vertebral augmentation, including vertebroplasty and kyphoplasty, is a minimally invasive, image-guided procedure in which cement (typically polymethylmethacrylate (PMMA)) is injected into a vertebral body to treat painful fractures. The majority of vertebroplasty and kyphoplasty procedures are performed to treat symptomatic osteoporotic compression fractures refractory to conservative medical therapy; however, there is also evidence to suggest the benefits of augmentation in patients with refractory pain in the acute compression setting. The primary goal of augmentation is decreasing pain and improving a patient's functional status. The secondary goal of augmentation is vertebral body stabilization. This chapter outlines the indications, contraindications, techniques, and literature behind vertebral augmentation.

Preliminary application of CPC/PMMA composite bone cement in kyphoplasty for the elderly

From the perspective of clinical application to analyze the effectiveness and reliability of CPC/PMMA bone cement in percutaneous kyphoplasty (PKP) for the treatment of elderly patients with osteoporotic thoracolumbar fractures. A retrospective analysis was performed on 62 patients with osteoporotic compression fracture of single-vertebral thoracic or lumbar segment who underwent PKP surgery and had a bone density less than or equal to -3.0 SD from February 2016 to December 2016. Among them, 23 patients were in CPC/PMMA group, with an average age of (77.6±2.2) years old, 39 patients in PMMA group, with an average age of (77.1±1.1) years old. The indexes between two groups were compared, including the visual analogue scale (VAS), height ratio of anterior vertebra (AVHR), local Cobb angle, cement leakage, new adjacent vertebral fracture(NAVF). There were no significant difference in gender, age, follow-up time and preoperative VAS, AVHR, local Cobb angle between two groups (P>0.05), at the 1 day after operation, VAS, AVHR, local Cobb angle in all patients got obvious improvement (P<0.05), which was no significant difference at 1 day after operation and final follow-up (P>0.05). At the same time, there was no statistically significant difference in the incidence of new adjacent vertebral fracture and cement leakage (P>0.05). The pain in both groups continued to improve at follow up after operation (P<0.05), the local Cobb angle increased (P<0.05) and AVHR decreased slightly (P<0.05). However, the images of conventional methods (X-ray or CT) could not find signs about CPC degeneration and new bone ingrowth. CPC/PMMA composite bone cement is safe and reliablein PKP for treatment of elderly patients with osteoporotic thoracolumbar fractures, which can effectively relieve pain and maintain vertebral body stability. It has the same curative effect as PMMA bone cement. It was worthy to research more in future, although no direct evidences support the CPC/PMMA composite bone cement can reduce the incidence of adjacent vertebral fracture, CPC degeneration or new bone ingrowth.

Assessment of Spinal Tumor Treatment Using Implanted 3D-Printed Vertebral Bodies with Robotic Stereotactic Radiotherapy

SummaryTo investigate the feasibility and early efficacy of 3D-printed vertebral body implantation combined with robotic radiosurgery in the treatment of spinal tumors. This study included 14 patients with spinal tumors from December 2017 to June 2018. Before surgery, all patients were subjected to CT scan and 3D data of the corresponding vertebral segments were collected. Titanium alloy formed 3D-printed vertebral body implantation and robotic stereotactic radiotherapy were performed because of the risk of postoperative residual, high risk of recovery, or recurrence after surgery. The main outcomes included the remission of symptoms, vertebral body stability, robotic stereotactic surgical precision, and local tumor control. All patients received complete and successful combination therapy, and all healed primarily without complications. The error of the coverage accuracy for robotic radiosurgery was less than 0.5 mm, and the error of the rotation angle was less than 0.5°. The therapeutic toxicity was limited (mainly in grades 1–2), and adverse events were uncommon. The evaluation of vertebral body stability and histocompatibility for all patients met the postoperative clinical requirements. For patients with post spinal injury, the pain symptoms were reduced or disappeared (93%), and nerve function was improved or even recovered after treatment (100%). During our follow-up period, most tumors were locally well controlled (93%). 3D- printed vertebral body implantation combined with robotic radiosurgery may offer a new treatment of spinal tumors.Chinese clinical trial registry: ChiCTR-ONN-17013946.

Minimally invasive non-fusion vertebral body stabilization in severe benign and malignant fractures. Stent-screw Assisted Internal Fixation: the SAIF technique

This short review focuses on clinical and therapeutic issues posed by severe osteoporotic and neoplastic insufficiency vertebral fractures and on the potential use of a new technique to obtain minimally invasive vertebral body reconstruction, augmentation, and stabilization in such severe fractures, combining two preexisting procedures. The implant of vertebral body stents is followed by insertion of percutaneous, fenestrated, cement-augmented pedicular screws that act as anchors to the posterior elements for the cement–stent complex. This procedure results in a 360° nonfusion form of vertebral internal fixation that may empower vertebral augmentation and potentially avoid corpectomy in challenging osteoporotic and neoplastic fractures.

Ventral stabilization of thoracic kyphosis through bilateral intercostal thoracotomies using SOP (String of Pearls) plates contoured after a 3-dimensional print of the spine.

To describe a novel vertebral body stabilization and report its outcome in dogs with thoracic kyphosis and secondary myelopathy. Case series. Six pugs with thoracic kyphosis and secondary myelopathy. Medical records (2012-2017) of dogs with chronic progressive pelvic limb ataxia and ambulatory proprioceptive paraparesis due to thoracic kyphosis were reviewed. Dogs were evaluated via MRI and computed tomography. A 3-dimensional print of the kyphotic vertebral segment was used to precontour the SOP (String of Pearls) plates. Bilateral double, dorsal intercostal thoracotomies were performed to place precontoured SOP on the vertebral bodies. Long-term (6-16 months) clinical outcome was determined on the basis of neurological scoring (NS) and owner questionnaire. The only intraoperative complication consisted of a lung laceration due to preexisting adhesions. Postoperative complications included seroma formation (n = 2) and incidental radiographic evidence of screw breakage (n = 2). NS at presentation ranged between 2 and 4 and improved to 1 at long-term follow-up in all dogs but 1 (NS = 2). All owners felt that their dog had excellent quality of life at follow-up. In spite of the challenging local anatomy, all dogs undergoing vertebral stabilization with SOP placement experienced a good clinical outcome. Stabilization of vertebral bodies with precontoured SOP placed through bilateral thoracotomies may be considered as a treatment option for dogs with thoracic kyphosis and secondary myelopathy.

Anterior Cervical Discectomy With Fusion Using a Local Source for Cancellous Autograft: A Biomechanical Analysis of Vertebral Body Stability in an Osteopenic Bone Model.

Background:Anterior cervical discectomy with fusion is an effective treatment for patients having cervical radiculopathy and myelopathy. To reduce morbidity associated with autograft taken from the iliac crest without sacrificing high fusion rates, a novel technique that harvests bone from the vertebral body adjacent to the operative disc space has been proposed. The effects of square and round bone graft harvest techniques on the mechanical stability of the osteopenic donor vertebrae are unknown. We analyzed the biomechanical implications of the technique by subjecting osteopenic models to uniaxial compression to compare yield strengths of surgically altered and unaltered specimens.Methods:Biomechanical grade polyurethane foam was cut into 60 different 12 mm × 17 mm × 20 mm blocks. The foam had a density of 10 pounds per cubic foot, simulating osteoporotic bone. Rectangular prism (4 mm × 4 mm × 6 mm) and cylindrical cores (r = 2 mm, h = 8 mm) were removed from 20 blocks per group. Twenty samples were left intact as a control group. Anterior plate screws were applied to the models and a Polyether ether ketone (PEEK) interbody spacer was placed on top. Samples underwent uniaxial compression at 0.1 mm/s until mechanical failure. Points of structural failure were determined using a 0.1% offset on a force–displacement curve and compared to determine the reductions in compressive strength.Results:The mean force eliciting structural failure for intact samples was 450.6 N. Average failure forces for rectangular prisms and cylindrical cores removed were 383.2 and 395.4 N, respectively. Removal of a rectangular prismatic core of the necessary volume resulted in a 15.0% reduction in compressive strength, while removal of a cylindrical core of comparable volume facilitated a reduction of 12.2%.Conclusion:Local autograft harvested from adjacent vertebrae reduces morbidity associated with a second surgical site while minimally reducing the compressive strength of the donor vertebra in an osteopenic model, lending credence to the efficacy of this technique in elderly patient populations.

The effect of screw tunnels on the biomechanical stability of vertebral body after pedicle screws removal: a finite element analysis

Posterior reduction and pedicle screw fixation is a widely used procedure for thoracic and lumbar vertebrae fractures. Usually, the pedicle screws would be removed after the fracture healing and screw tunnels would be left. The aim of this study is to evaluate the effect of screw tunnels on the biomechanical stability of the lumbar vertebral body after pedicle screws removal by finite element analysis (FEA). First, the CT values of the screw tunnels wall in the fractured vertebral bodies were measured in patients whose pedicle screws were removed, and they were then compared with the values of vertebral cortical bone. Second, an adult patient was included and the CT images of the lumbar spine were harvested. Three dimensional finite element models of the L1 vertebra with unilateral or bilateral screw tunnels were created based on the CT images. Different compressive loads were vertically acted on the models. The maximum loads which the models sustained and the distribution of the force in the different parts of the models were recorded and compared with each other. The CT values of the tunnels wall and vertebral cortical bone were 387.126±62.342 and 399.204±53.612, which were not statistically different (P=0.149). The models of three dimensional tetrahedral mesh finite element of normal lumbar 1 vertebra were established with good geometric similarity and realistic appearance. After given the compressive loads, the cortical bone was the first one to reach its ultimate stress. The maximum loads which the bilateral screw tunnels model, unilateral screw tunnel model, and normal vertebral model can sustain were 3.97 Mpa, 3.83 Mpa, and 3.78 Mpa, respectively. For the diameter of the screw tunnels, the model with a diameter of 6.5 mm could sustain the largest load. In addition, the stress distributing on the outside of the cortical bone gradually decreased as the thickness of the tunnel wall increased. Based on the FEA, pedicle screw tunnels would not decrease the biomechanical stability and strength of the vertebral body. A large diameter of screw tunnel and thick tunnel wall were helpful for the biomechanical stability of the vertebral body.

Fracture risk of vertebral bodies after cryosurgery using a miniature cryoprobe: A biomechanical in-vitro analysis on human bones.

Due to spinal instability and compressive neurologic deficits surgical management is sometimes necessary in patients with metastatic spinal lesions. However, in some cases open surgery is not possible and minimally invasive procedures, like cryoablation, are needed. The aim of the current study was to investigate whether a miniature cryoprobe provides adequate tissue cooling in vertebrae and to evaluate the direct impact of cryosurgery on vertebral body stability. Twelve thoracic vertebral bodies were harvested from fresh cadavers. After documenting bone density cryoablation was performed in six vertebral bodies according to a standardized procedure. Afterwards temperature inside the vertebral body and maximum breaking force were measured in the control and experimental groups. Required temperature of -50° was reached in all areas. There was a significant correlation between maximum breaking force and measured bone density (p= 0.001). Mean breaking force within the experimental group was 5047 N (SD = 2955 N) compared to 4458 N (SD = 2554 N) in the control group. There were no observable differences in maximum breaking force between both groups. Miniature cryoprobe can deliver adequate tissue cooling to -50°C in vertebral bodies. The procedure does not seem to influence breaking force of the treated bones in-vitro. Therefore, using miniature probes cryosurgery may provide a valuable alternative to conventional surgical resection of neoplastic diseases as well as of benign locally aggressive bone tumors.

Spine Oncology-Metastatic Spine Tumors.

Surgery for spinal metastases remains the mainstay treatment for pain, instability, and neurological deterioration due to tumor infiltration of the spine. However, several new therapies are emerging which may improve outcomes further, and in some cases even replace the need for surgery. We now have a better understanding of which factors influence survival and quality of life after surgery, and this underpins the development and application of new treatments, and assessment of outcome.Depending on genetic subtyping of tumors, novel immunotherapies and chemotherapies may be very effective in prolonging quality of life. New surgical techniques allow smaller, quicker, and safer operations with less blood loss, pain, and quicker recovery after surgery. Radiation treatments have also leapt forward with the greater accuracy and higher doses possible from intensity-modulated photon radiation, stereotactic body radiation treatment, proton beam therapy, or carbon ion treatment. Combined with more advanced materials for vertebral body stabilization, computer navigation systems, and robotics, more can be done at earlier or later stages of the spinal disease than was previously possible, resulting in more options and improved outcomes for patients.

Association of osteolytic lesions, bone mineral loss and trabecular sclerosis with prevalent vertebral fractures in patients with multiple myeloma

PurposeIn patients with multiple myeloma (MM), computed tomography is widely used for staging and to detect fractures. Detecting patients at severe fracture risk is of utmost importance. However the criteria for impaired stability of vertebral bodies are not yet clearly defined. We investigated the performance of parameters that can be detected by the radiologist for discrimination of patients with and without fractures. Methods and materialsWe analyzed 128 whole body low-dose CT of MM patients. In all scans a QCT calibration phantom was integrated into the positioning mat (Image Analysis Phantom®). A QCT-software (Structural Insight) performed the volumetric bone mineral density (vBMD) measurements. Description of fracture risk was provided from the clinical radiological report. Suspected progressive disease (PD) was reported by the referring clinicians. Two radiologists that were blinded to study outcome reported on the following parameters based on predefined criteria: reduced radiodensity in the massa lateralis of the os sacrum (RDS), trabecular thickening and sclerosis of three or more vertebrae (TTS), extraosseous MM manifestations (EOM), visible small osteolytic lesions up to a length of 8mm (SO) and osteolytic lesions larger than 8mm (LO). Prevalent vertebral fractures (PVF) were defined by Genant criteria. Age-adjusted standardized odds ratios (sOR) per standard deviation change were derived from logistic regression analysis and area under the curve (AUC) from receiver operating characteristics (ROC) analyses were calculated. ROC curves were compared using the DeLong method. Results45% of the 128 patients showed PVF (29 of 75 men, 24 of 53 women). Patients with PVF were not significantly older than patients without fractures (64.6±9.2 vs. 63.3±12.3 years: mean±SD, p=0.5). The prevalence of each parameter did not differ significantly by sex. Significant fracture discrimination for age adjusted single models was provided by the parameters vBMD (OR 3.5 [1.4–8.8], AUC=0.64±0.14), SO (sOR 1.6[1.1–2.2], AUC=0.63±0.05), LO (sOR 2.1[1.1–4.2] AUC=0.69±0.05) and RDS (sOR 2.6[1.6–4.7], AUC=0.69±0.05). Multivariate models of these four parameters showed a significantly stronger association with the development of PVF (AUC=0.80±0.04) than single variables. TTS showed a significant association with PVF in men(sOR 1.5 [0.8–3.0], AUC=0.63±0.08), but not in women (sOR 2.3[1.4–3.7], AUC=0.70±0.07). PD was significantly associated with PVF in women (sOR 1.9[1.1–3.6], AUC=0.67±0.08) but not in men (sOR 1.4[0.9–2.3], AUC=0.57±.07). EOM were not associated with PVF (sOR 1.0[0.4–2.6], AUC=0.51±.05). ConclusionIn multiple myeloma, focal skeletal changes in low dose CT scans show a significant association with prevalent vertebral fractures. The combination of large osteolytic lesions and loss in radiodensity as can be detected with simple CT Hounsfield measurements of the os sacrum or BMD measurements showed the strongest association to fractures and may be of value for prospective studies.

Stability of spinal bone metastases and survival analysis in renal cancer after radiotherapy.

This retrospective analysis evaluated the outcome of patients with spinal bone metastases of renal cell cancer after radiotherapy (RT) in terms of stability and survival, using a validated scoring system for spinal stability assessment. The survival rates of 155 patients with bone metastases of renal cancer treated from January 2000 to January 2012 were determined. The stability of irradiated osteolytic lesions of the thoracic and lumbar spine was evaluated retrospectively using the Taneichi score and analyzed for predictive factors. The effects of therapy in terms of changes in neurological signs and tumor-related pain were recorded. Follow-up with regular computed tomography (CT) was available for 28 patients, 14 with unstable metastases. One hundred thiry-two patients (85%) died during follow-up. RT could not improve the stability of vertebral bodies after 3 and 6 months. Consequently, none of the examined predictive factors such as age, number of bone metastases and systemic therapy showed a significant correlation with stability 6 months after RT. The median survival of all 155 patients after diagnosis of bone metastases was 12.9 months. Improvement of pain and neurological deficits occurred in 60%, and in 24% of the respective affected in all patients. RT was unable to improve the stability of vertebral metastases, probably due to the short overall survival, which resulted in an insufficient number of patients with evaluable follow-up. RT allowed reduction of pain and neurological deficits. A short fractionation schedule may be preferred in this situation.

Palliative Strategies for the Management of Primary and Metastatic Spinal Tumors

Technological advances during the last few decades have improved the success rate of surgery for the treatment of malignant spinal tumors. Nonetheless, many patients present with widespread tumor burden and minimal life expectancy, which excludes them from being surgical candidates. For these patients, palliative management is recommended. The authors reviewed prospective and retrospective clinical studies as well as case series regarding palliative treatments for primary and metastatic spinal tumors. Analgesics, ranging from nonopioids to strong opioids, may be used depending on the degree of pain. Steroids may also improve pain relief, although they are associated with a number of adverse events. Vertebroplasty and kyphoplasty are conservative treatments with high rates of pain relief and vertebral body stabilization. Radiotherapy is the gold standard for palliative management, with approximately 60% of patients experiencing a decrease in tumor-related spinal pain and up to 35% experiencing complete relief. Stereotactic radiosurgery delivers high doses of radiation to patients to provide pain relief while also sparing delicate anatomical structures. Palliative management of spinal tumors is diverse. Analgesics may be used in conjunction with radiotherapy and/or kyphoplasty or vertebroplasty to offer pain relief.

Intra-operative vertebroplasty combined with posterior cord decompression. A report of twelve cases.

Percutaneous vertebroplasty (VP) is a minimally invasive technique for the treatment of vertebral pathology providing early vertebral stabilization and pain relief. In cases of vertebral pathology complicated by spinal cord compression with associated neurological deficits, VP alone cannot be performed free of risks. We describe a combined approach in which decompressive laminectomy and intra-operative vertebroplasty (IVP) are performed during a single session. Among the 252 VP performed in our centre in the past three years, 12 patients (12 vertebral levels) with different pathologies (six symptomatic haemangiomas, two metastatic fractures, four osteoporotic fractures) were treated with an open procedure combined with surgery. All cases were treated with decompressive laminectomy and IVP (mono/bipeduncular or median-posterior trans-somatic access). Five patients with symptomatic haemangiomas were treated with endovascular embolization prior to the combined approach. A visual analogue scale (VAS) was applied to assess pain intensity before and after surgery. The neurological deficits were evaluated with an ASIA impairment scale. In all cases benefit from pain and neurological deficits was observed. The mean VAS score decreased from 7.8 to 2.5 after surgery. The ASIA score improved in all cases (five cases from D to E and five cases from C to D). No clinical complications were observed. In one case a CT scan performed after the procedure showed a foraminal accumulation of PMMA, but the patient referred no symptoms. IVP can be successfully applied in different pathologies affecting the vertebrae. In our limited series this approach proved safe and efficient to provide decompression of spinal cord and dural sac and vertebral body stabilization in a single session.

Kyphoplasty for Malignant Mesothelioma Metastasis to the L5 Vertebra for Spine Stabilization

Malignant mesothelioma (MM) is an aggressive primary malignancy which invades the pleura, peritoneum or pericardium. Mortality rates are high. Local tumor invasion is inevitable; and metastasis to the chest wall, mediastinum, or thoracic spine is common. Distal metastasis to osseous structures other than the thoracic spine is rare. External beam radiation therapy (EBRT) is a mainstay treatment for metastatic disease in the spine but carries significant risks of myelopathy and unintended damage to normal surrounding tissues and is insufficient when mechanical instability of the affected vertebra is present. Further, EBRT may take up to 2 weeks to elicit meaningful pain relief. Balloon kyphoplasty (KP) is a brief, safe, outpatient, image-guided percutaneous procedure performed with either twilight sedation or general anesthesia. The ideal KP candidate has midline non-radiating pain which worsens with weight bearing and direct palpation at the site of vertebral metastasis or fracture, and pain which improves in the supine position. We present a rare case of L5 vertebral metastasis from end-stage recalcitrant MM treated with KP for pain control and vertebral body stabilization. KP should be considered as a palliative treatment option, with strong evidence to suggest predictable pain relief and improved function when appropriate candidates are selected for the procedure. Caregivers should be aware of the indications of KP as well as expected outcomes.

Percutaneous vertebroplasty in patients with osteoportic vertebral body fractures

Percutaneous vertebroplasty in patients with osteoportic vertebral body fractures

Effects of tumor location, shape and surface serration on burst fracture risk in the metastatic spine

Spinal metastatic disease occurs in up to one-third of all cancer patients. Advanced spread can lead to vertebral burst fracture, which may result in neurologic compromise. Developing a better understanding of factors affecting burst fracture risk has significant clinical importance, as early intervention can prevent vertebral fracture in high-risk patients. The primary objective of this study was to quantify the effects of tumor location and shape on vertebral body stability and burst fracture risk in the metastatic spine using poroelastic parametric finite element modeling. This study also compared two distinct surface modeling techniques in the representation of lytic defects. A total of 16 ellipsoidal tumor scenarios were analyzed. Single tumors were situated in central, anterior, posterior, superior, inferior, and lateral locations, with smooth and serrated tumor surfaces. Two central shapes and two serrated surface multi-tumor scenarios were also analyzed. Outcome parameters of maximum vertebral bulge and axial displacement were assessed as representative of burst fracture risk. Posterior movement of the tumor caused the greatest increase in vertebral bulge. Tumor shape also affected burst fracture risk. The multi-tumor scenarios yielded the greatest reductions in both vertebral bulge and axial displacement. Serrated tumor scenarios abided by similar trends as smooth tumor scenarios, although tumor serration caused a slight increase in fracture risk. Tumor shape and volume are best controlled by smooth surface modeling. Improved understanding of factors contributing to metastatic burst fracture risk will aid in directing future modeling efforts and in the development of accurate risk assessment criteria.

Percutaneous radiologically-guided vertebroplasty in the treatment of osteoporotic and tumorous spinal body lesions

Vertebroplasty is a radiological intervention for the augmentation of bone lesions with bone cement. Main indications are the treatment of osteoporotic vertebral body fractures, however also the treatment of tumorous lesions becomes more and more established. The indication for vertebroplasty of tumorous lesions is therapy-refractory pain in symptomatic hemangiomas, metastases and myelomas. By minimal invasive therapy stabilization of vertebral bodies and pain reduction may be achieved.