Methyl-methacrylate bone cement surface does not promote platelet aggregation or plasma coagulation in vitro

Novel Photo- and Thermo-Responsive Nanocomposite Hydrogels Based on Functionalized rGO and Modified SIS/Chitosan Polymers for Localized Treatment of Malignant Cutaneous Melanoma

Melanoma is an aggressive type of skin cancer that accounts for over 75% of skin cancer deaths despite comprising less than 5% of all skin cancers. Despite promising improvements in surgical approaches for melanoma resection, the survival of undetectable microtumor residues has remained a concern. As a result, hyperthermia- and drug-based therapies have grown as attractive techniques to target and treat cancer. In this work, we aim to develop a stimuli-responsive hydrogel based on chitosan methacrylate (ChiMA), porcine small intestine submucosa methacrylate (SISMA), and doxorubicin-functionalized reduced graphene oxide (rGO-DOX) that eliminates microtumor residues from surgically resected melanoma through the coupled effect of NIR light-induced photothermal therapy and heat-induced doxorubicin release. Furthermore, we developed an in silico model to optimize heat and mass transport and evaluate the proposed chemo/photothermal therapy in vitro over melanoma cell cultures.

Preparation and Characterization of an Injectable and Photo-Responsive Chitosan Methacrylate/Graphene Oxide Hydrogel: Potential Applications in Bone Tissue Adhesion and Repair

As life expectancy continues to increase, the inevitable weakening and rupture of bone tissue have grown as concerns in the medical community, thus leading to the need for adhesive materials suitable for bone repair applications. However, current commercially available adhesives face certain drawbacks that prevent proper tissue repair, such as low biocompatibility, poor adhesion to wet surfaces, and the need for high polymerization temperatures. This work aims to develop an injectable and photo-responsive chitosan methacrylate/graphene oxide (ChiMA/GO) adhesive nanocomposite hydrogel of high biocompatibility that is easy to apply by simple extrusion and that offers the possibility for in situ polymer and physiological temperatures. The nanocomposite was thoroughly characterized spectroscopically, microscopically, rheologically, thermally, and through mechanical, textural, and biological assays to fully evaluate its correct synthesis and functionalization and its performance under physiological conditions that mimic those observed in vivo. In addition, a finite element analysis (FEA) simulation was used to evaluate its performance in femur fractures. Results suggest the material’s potential as a bioadhesive, as it can polymerize at room temperature, shows superior stability in physiological media, and is capable of withstanding loads from body weight and movement. Moreover, the material showed remarkable biocompatibility as evidenced by low hemolytic and intermediate platelet aggregation tendencies, and high cytocompatibility when in contact with osteoblasts. The comprehensive studies presented here strongly suggest that the developed hydrogels are promising alternatives to conventional bone adhesives that might be further tested in vivo in the near future.

Long-Term Outcomes of Peripheral Pulmonary Cement Embolism in Patients with Polymethylmethacrylate Augmentation: A Case Series with a Minimum Follow-Up of Five Years

BACKGROUND

Pulmonary cement embolism (PCE) is a rare but lethal complication. However, few long-term follow-up studies have investigated PCE after polymethylmethacrylate augmentation. This study aimed to investigate both the clinical and imaging outcomes of patients with PCE during a follow-up period of at least 5 years.

METHODS

A total of 1460 patients were initially included in this retrospective study. After exclusion, the clinical and imaging data were analyzed for selected patients, including the augmented level, location and length of the PCE, symptoms, therapy, migration and disintegration of the embolism, foreign body reaction, and status at follow-up.

RESULTS

Twelve female patients (age range, 56-88 years) with PCE and more than 5 years of follow-up (range, 5-13 years) were eventually included. All emboli were found in subsegment pulmonary arteries and were classified as peripheral PCE. Although 2 patients experienced transient symptoms after surgery, the majority of patients (84.6%) were asymptomatic during follow-up. No other reported emboli were observed during the follow-up period. The imaging data showed that the cement embolus could remain in the initial position throughout the long-term follow-up. In terms of the length of the PCE, there was no statistically significant difference between the values post-operation and at the last follow-up time (P > 0.05).

CONCLUSIONS

Patients with peripheral PCE do not develop known late complications. Moreover, polymethylmethacrylate can remain stable and inert in the pulmonary vasculature over the long term. Routine prophylactic anticoagulation may not be necessary for patients with peripheral PCE during follow-up.

Cement Pulmonary Embolism Due to Percutaneous Vertebroplasty

BACKGROUND

Bone cement is an uncommon cause of foreign-body pulmonary embolism.

CASE PRESENTATION

A 65-year-old woman with wheeze presented with multiple linear opacities with bone density on chest x-ray. She reported percutaneous vertebroplasty 4 months prior. Non-- contrast chest computerized tomography showed peripheral cement emboli in the pulmonary arteries. The patient received conservative treatment.

CONCLUSION

Clinicians should be aware of this potential complication following vertebroplasty. It is necessary to perform a chest x-ray after the procedure.

Bone cement implantation syndrome during hip replacement in a patient with pemphigus and Parkinson’s disease: A case report

BACKGROUND

Bone cement implantation syndrome (BCIS) is characterized by hypotension, arrhythmia, diffuse pulmonary microvascular embolism, shock, cardiac arrest, any combination of these factors, or even death following bone cement implantation.

CASE SUMMARY

An 80-year-old patient with pemphigus and Parkinson’s disease underwent total hip replacement under spinal subarachnoid block and developed acute pulmonary embolism after bone cement implantation. The patient received mask mechanical ventilation with a continuous intravenous infusion of adrenaline (2 μg/mL) at a rate of 30 mL/h. Subsequently, the symptoms of BCIS were markedly alleviated, and the infusion rate of adrenaline was gradually reduced until the infusion was completely stopped 45 min later. The patient was then transferred to the Department of Orthopedics, and anticoagulation therapy began at 12 h postoperatively. No other complications were observed.

CONCLUSION

This is a rare case of BCIS in a high-risk patient with pemphigus and Parkinson’s disease.

Unexpected pacemaker lead in an 84-year-old patient

An elderly patient with a history of atrial fibrillation presented to our emergency room. Previous medical records from another hospital described a pacemaker lead in the echocardiography although the patient had no known history of a pacemaker implantation. Finally, by close examination, chest X-ray, and computed tomography, we found that a kyphoplasty of the spine had caused a so-called palacos embolism, which had repeatedly been mistaken for a pacemaker lead. Unusually, there were no further signs of kyphoplasty material in the pulmonary veins. As the patient was asymptomatic and the embolism caused only moderate tricuspid regurgitation, a conservative treatment was agreed on.

Single-center outcomes for percutaneous pedicle screw fixation in metastatic spinal lesions: can spontaneous facet fusion occur?

OBJECTIVE

Survival of cancer patients continues to improve with systemic treatment advancements, leading to an increase in cancer-related complications such as pathological spinal fractures. In this study, the authors aimed to evaluate the outcome of percutaneous stabilization with cement augmentation of the pedicle screws in the management of patients with metastatic cancer to the spine.

METHODS

The authors reviewed a retrospective case series of 74 patients with symptomatic pathological spine fractures treated with cement-augmented pedicle screws implanted with a percutaneous technique. The mean imaging follow-up was 11.3 months. Data on demographics, clinical outcomes, and complications were collected. Cement extravasation, spinal hardware integrity, and fusion rates were assessed on CT scans.

RESULTS

Among 50 patients with follow-up imaging, 23 patients (46%) showed facet joint fusion. The length of segmental stabilization was not a significant predictor of the occurrence of fusion. Pre- or postoperative radiation therapy, postoperative chemotherapy, and the location of spinal lesions did not have a statistically significant effect on the occurrence of fusion. Patients older than 60 years of age were more likely to have fusion across facet joints compared with younger patients. There was a significant difference in the mean visual analog scale pain score, with 6.28 preoperatively and 3.41 postoperatively, regardless of fusion status (p < 0.001). Cement extravasation was seen in 51% of the cohort, but in all instances, patients remained asymptomatic. Most importantly, the incidence of hardware failure was low (4%).

CONCLUSIONS

Percutaneous fixation with cement-augmented pedicle screws in patients with pathological spine fractures provides an improvement in mechanical back pain, with a low incidence of failure, and in some patients, spontaneous facet fusion was observed. Further research is necessary with regard to both short-term benefits and long-term outcomes.

Pulmonary embolism with coexistent incidental pulmonary cement embolism post vertebroplasty

A 46-year-old woman presented with sudden onset of shortness of breath and pleuritic chest pain. A CT pulmonary angiogram identified a 5 cm cement pulmonary embolus within the right main pulmonary artery with a surrounding thrombus. She had undergone an L4 vertebroplasty 3 years prior to presentation for a benign lytic lesion. Cement embolus is a known complication of cement vertebroplasty with incidence rates of approximately 0.9%. Management is usually conservative and associated morbidity and mortality rates are low. It is not known whether a previous cement embolus could provide a nidus for thrombus formation.

Utility of Cement Augmentation via Percutaneous Fenestrated Pedicle Screws for Stabilization of Cancer-Related Spinal Instability

BACKGROUND

Cancer patients experience pathological fractures and the typical poor bone quality frequently complicates stabilization. Methods for overcoming screw failure include utilization of fenestrated screws that permit the injection of bone cement into the vertebral body to augment fixation.

OBJECTIVE

To evaluate the safety and efficacy of cement augmentation via fenestrated screws.

METHODS

A retrospective chart review of patients with neoplastic spinal instability who underwent percutaneous instrumented stabilization with cement augmentation using fenestrated pedicle screws. Patient demographic and treatment data and intraoperative and postoperative complications were evaluated by chart review and radiographic evaluation. Prospectively collected patient reported outcomes (PRO) were evaluated at short (2- <6 mo) and long term (6-12 mo).

RESULTS

Cement augmentation was performed in 216 fenestrated pedicle screws in 53 patients. Three patients required reoperation. One patient had an asymptomatic screw fracture at 6 mo postoperatively that did not require intervention. No cases of lucency around the pedicle screws, rod fractures, or cement extravasation into the spinal canal were observed. Eight cases of asymptomatic, radiographically-detected venous extravasation were found. Systemic complications included a pulmonary cement embolism, a lower extremity deep vein thrombosis, and a postoperative mortality secondary to pulmonary failure from widespread metastatic pulmonary infiltration. Significant improvement in PRO measures was found in short- and long-term analysis.

CONCLUSION

Cement augmentation of pedicle screws is an effective method to enhance the durability of spinal constructs in the cancer population. Risks include cement extravasation into draining blood vessels, but risk of clinically significant extravasation appears to be exceedingly low.

Clinical characteristics and management of cardiac and/or pulmonary cement embolus after percutaneous vertebroplasty: a single center experience

Background

Cardiac and/or pulmonary cement embolus (CPCE) caused by the leakage of bone cement after percutaneous vertebroplasty (PVP) are rare but are lethal complications in patients with vertebral compression fracture (VCF). Literature in this field is limited, and guidelines for the management of such complications are unclear. This study aimed to review our center's experience.

Methods

Medical records (clinical characteristics and management) and imaging data (X-ray findings, CT findings, and fluoroscopic findings) of 12 patients with CPCE after PVP between October 2015 and July 2018 at our hospital were collected and examined retrospectively. Their health conditions were also evaluated through a telephone follow-up survey.

Results

Twelve patients with an average age of 76.8±8.5 years were included in our study. One patient who had a cardiac cement embolus and one patient who suffered from an inferior vena cava (IVC) cement embolus were successfully treated via percutaneous retrieval. Ten asymptomatic patients with pulmonary cement embolus (PCE) were managed with conservative observation. All of the patients were alive and remained asymptomatic during the follow-up period (median time, 6.5 months; range, 1-50 months).

Conclusions

More attention should be paid to the possibility of development of CPCE. For patients with cardiac cement embolus, open heart surgery should be considered as a preferred treatment, and percutaneous procedure could be used as an alternative treatment for patients with surgical contraindication or other surgical high-risk factors. For patients with an IVC cement spike, percutaneous retrieval could be recommended. Careful observation and clinical follow-up could be recommended for patients with asymptomatic peripheral or central PCEs.

Pulmonary cement embolism following balloon kyphoplasty: The impact of a procedural complication in a new era for lung cancer management

Pulmonary cement embolism (PCE) is a recognized complication of balloon kyphoplasty, a vertebral augmentation technique that stabilizes vertebral compression fractures, alleviating associated pain. Balloon kyphoplasty is particularly relevant when patients with advanced stages of cancer present with longer survival times, and therefore benefit from such augmentation techniques to improve pain and prevent additional complications. The embolization of cement to pulmonary vasculature may be unnoticed given the frequent absence of symptoms and routine imaging tests following the procedure. The present study reports the case of a 58-year-old female with stage IV lung cancer with a painful compression L3 fracture who underwent balloon kyphoplasty with no initially reported complications. The patient maintained the usual respiratory symptoms; therefore, the diagnosis was only made in a routine CT scan 3 months after the surgery. A literature review of PCE is performed, integrating the current evidence regarding diagnosis, therapeutics, prognosis and prevention. Certain poorly clarified aspects are identified as potential investigation starting points.

Nonthrombotic Pulmonary Embolism From Inorganic Particulate Matter and Foreign Bodies

Nonthrombotic pulmonary embolism (NTPE) is a complete or partial occlusion of the pulmonary vasculature by various organic and inorganic materials. These materials include organic particulate matter (PM) such as adipocytes, tumor cells, bacteria, fungi, or gas and inorganic PM. Although NTPE due to organic PM has been extensively reported in the medical literature, there are no comprehensive reviews of inorganic material embolizing to the lungs. The purpose of this article is to examine the current literature describing NTPE resulting from inorganic PM and foreign bodies. Cases of NTPE are uncommon and often difficult to diagnose. The diagnosis is challenging due to its varied presentation, clinical features, and unusual radiologic features. In contrast to the "classic" pulmonary thromboembolism, the pathophysiologic effects of embolism by PM are not only mechanical but also a consequence of the nature of the offending material. NTPE caused by these substances can be relatively innocuous, life-threatening, or lead to chronic pulmonary disease, if left undetected. We hope that the heightened sense of awareness of this entity may allow earlier diagnosis and recognition of its complications.

Hemocompatibility evaluation in vitro of methoxy polyethyleneglycol-polycaprolactone copolymer solutions

Amphiphilic block copolymer methoxy polyethyleneglycol-polycaprolactone (mPEG-PCL) has attracted interest in the biomedical field, due to its water solubility and biodegradability. Nevertheless, the blood safety of mPEG-PCL copolymers has not been investigated in detail. Because mPEG-PCL copolymers introduced in vivo would inevitably interact with blood tissue, an investigation of possible interactions of mPEG-PCL with key blood components is crucial. We studied the effects of two mPEG-PCL copolymer solutions on blood coagulation, the morphology and lysis of human red blood cells (RBCs), the structure of plasma fibrinogen, complement activation, and platelet aggregation. We found that higher concentrations of the mPEG-PCL copolymers impaired blood clotting, and the copolymers had little impact on the morphology or lysis of RBCs. From the spectroscopy results, the copolymers affected the local microstructure of fibrinogen. The copolymers significantly activated the complement system in a concentration-dependent way. At higher concentrations, the copolymers impaired platelet aggregation, which may have been mediated by an inhibition of the arachidonic acid pathway. These findings provide important information that may be useful for the molecular design and biomedical applications of mPEG-PCL copolymers. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 802-812, 2016.

Pulmonary cement embolization after vertebroplasty, an uncommon presentation of pulmonary embolism: A case report and literature review

Pulmonary Cement Embolization (PCE) is a rare complication of vertebroplasty surgery. There is no clear guideline for management of this entity. There is no definite protocol for anticoagulation in PCE. This is a case report of our patient who was diagnosed to have Pulmonary Cement Embolization, which was quite significant involving both lungs. She was successfully managed without long term anticoagulation.

Bioengineered mussel glue incorporated with a cell recognition motif as an osteostimulating bone adhesive for titanium implants

An engineered mussel glue MAP-RGD can be successfully used as a novel functional osteostimulating bone adhesive for titanium implants through improved osteoblastic cell behaviors, blood responses, and eventually enhanced bone regeneration.

Association between deep vein thrombosis and the temperature at the popliteal fossa during cement curing in total knee arthroplasty

The temperature at the popliteal fossa during cement curing and its relationship with deep vein thrombosis (DVT) in total knee arthroplasty (TKA) has not been investigated. Fifty-six consecutive patients who underwent primary TKA were recruited. The temperatures at the popliteal fossa were measured during bone cement exothermic polymerization. Postoperative operated leg ascending venographies were performed 5 days after TKA for screening of DVT. The maximum temperatures were 32.5°C ± 1.0°C at the popliteal fossa during cement curing. No significant difference was found of the maximum temperatures in the popliteal fossa between the non-DVT and DVT groups. The present study indicated that the heat resulting from polymerization of the cement may not be a possible cause of damage to the veins surrounding the knee, and it may have no relationship with DVT.

Echocardiographic accidental finding of asymptomatic cardiac and pulmonary embolism caused by cement leakage after percutaneous vertebroplasty

Percutaneous vertebroplasty (PVP) is a therapeutic, interventional radiological procedure involving bone cement injection into a vertebral body. Although PVP is considered a minimally invasive procedure, cement leakage into the perivertebral venous system can occur with its migration towards the right heart and the pulmonary circulation. We report a case of accidental finding of asymptomatic cardiac and pulmonary embolism caused by cement leakage after PVP.

Influence of bone marrow fat embolism on coagulation activation in an ovine model of vertebroplasty

BACKGROUND

Intraoperative cardiovascular deterioration as a result of pulmonary embolization of bone marrow fat is a potentially serious complication during vertebroplasty. The release of fatty material and thromboplastin from the bone marrow cavity during vertebroplasty may activate the coagulation cascade resulting in thrombogenesis, and pharmacological prophylaxis may therefore prevent cardiovascular complications. Thus, the effects of bone marrow fat embolism on coagulation activation during vertebroplasty were investigated with use of an animal model.

METHODS

Polymethylmethacrylate was injected into three lumbar vertebrae of six sheep in order to force bone marrow fat into the circulation. Invasive blood pressures and heart rate were recorded continuously until sixty minutes after the last injection. Cardiac output, arterial and mixed venous blood gas parameters, and coagulation parameters were measured at selected time-points. Postmortem lung biopsy specimens were assessed for the presence of intravascular fat.

RESULTS

Embolization of bone marrow fat resulted in a sudden and dramatic increase in mean pulmonary arterial pressure and a decrease in mean arterial blood pressure. There were no significant changes in any coagulation parameter from before the injection to after the injection. Intravascular fat and bone marrow cells were present in all lung lobes.

CONCLUSIONS

Injection of polymethylmethacrylate into vertebral bodies caused embolization of bone marrow fat with subsequent transient cardiovascular deterioration, but no changes in coagulation parameters were observed. Thromboembolism did not contribute to the observed cardiovascular changes.

Cardiovascular changes after pulmonary cement embolism: an experimental study in sheep

BACKGROUND AND PURPOSE

Most cement leaks during vertebroplasty are asymptomatic, but pulmonary cement embolism has been reported to cause cardiovascular disturbances and even death. Adding hydroxyapatite (HA) to polymethylmethacrylate (PMMA) cement to reduce the quantity of barium may aggravate cardiovascular deterioration in the event of cement embolism by activating coagulation. Thus, we investigated the cardiovascular changes after pulmonary cement embolism of PMMA with and without HA.

MATERIALS AND METHODS

In 13 sheep, cement (2.0 mL) was injected into the pulmonary trunk. Two different cements were used: 1) standard PMMA and 2) PMMA with 10% HA (PMMA & HA). Arterial, central venous and pulmonary arterial pressures, heart rate, and cardiac output were monitored continuously until 60 minutes after the injection. Blood gases and coagulation parameters (antithrombin, D-dimer) were measured before and after injection.

RESULTS

Mean pulmonary arterial pressure had increased by approximately 9% (PMMA) and 14% (PMMA & HA) 1 minute after injection and stayed elevated. There were no significant differences between the groups. No evidence of thromboembolism was detected.

CONCLUSION

Cement embolism did not result in clinically significant pulmonary arterial hypertension. Adding HA to PMMA cement did not cause more severe cardiovascular changes.

Komplikation im Rahmen der Kyphoplastie

A 59-year-old woman had a nontraumatic osteoporotic fracture of the seventh thoracic vertebral body. Despite correct operative technique, in the course of kyphoplasty cement was dislocated through the segment vein into the azygos vein and from there into the superior vena cava. The patient was free of cardiopulmonary symptoms throughout. Oral anticoagulation was administered for 3 months to prevent thromboembolism, and regular clinical and echocardiographic follow-up examinations were also performed during this period.

Current concepts and techniques in percutaneous vertebroplasty

Percutaneous vertebroplasty is a safe and effective alternative for the treatment of many different types of painful vertebral lesions, including osteoporotic compression fractures,hemangiomas, or malignancy-induced pathologic vertebral fractures. Medical therapy often is limited to pain control and immobilization. Because surgery is contraindicated frequently in patients who have osteoporotic compression fractures, and because patients who have widespread metastatic disease often are not surgical candidates, vertebroplasty may be the only practical option. In experienced hands and with appropriately selected patients, percutaneous vertebroplasty is a safe, inexpensive, and highly efficacious procedure; however, because of the potential for devastating complications, all efforts must be made to optimize patient safety.

Anterior spinal column augmentation with injectable bone cements

A vertebral fracture, whether originating from osteoporosis or trauma, can be the cause of pain, disability, deformation and neurological deficit. The treatment of vertebral compression fractures has, for many years until the advent of vertebroplasty, consisted of bedrest and analgesics. Vertebroplasty is a percutaneous technique during which bone cement is injected in a vertebral body to provide immediate pain relief by stabilization. Inflatable bone tamps can, prior to the injection of cement, be used to create a void in the vertebral body, in which case the technique is known as balloon vertebroplasty (or kyphoplasty). The chance of extracorporal cement leakage is smaller for balloon vertebroplasty than for vertebroplasty. Some authors also claim to have gained some correction in vertebral body height or angulation. Both interventions can be used for several indications, including osteoporotic compression fractures and osteolytic lesions of the vertebral body such as myeloma, hemangioma or metastasis, and also for traumatic burst fractures in combination with pedicle screw instrumentation. Polymethyl methacrylate cement is the bone void filler that is used most frequently, although the application of calcium phosphate cements has been studied widely in vitro, in vivo and also in small-scale clinical series. The clinical results of (balloon-) vertebroplasty are favorable with 85-95% of all patients experiencing immediate and long-lasting relief of pain. Serious complications are relatively rare but include neurological deficit and pulmonary embolism. In this paper, both vertebroplasty and balloon vertebroplasty and their respective indications, techniques and results are described in relation with the application and limitations of permanent and resorbable injectable bone cements.