Wear and corrosion of titanium alloy spinal implants in vivo.

To investigate the wear and corrosion of titanium alloy spinal implants in vivo, we evaluated removed implants and their surrounding scar tissues from 27 patients between May 2019 and April 2021. We performed scanning electron microscopy, energy-dispersive X-ray spectroscopy, and histological analysis. The results revealed metal-like particles in the soft tissues of seven patients, without any considerable increase in inflammatory cell infiltration. Patients with fractures showed lower percentages of wear and corrosion compared with other patients (42% and 17% vs. 59% and 26%). Polyaxial screws exhibited higher wear and corrosion percentages (53% and 23%) compared with uniaxial screws (39% and 3%), although in patients with fracture, the reverse was observed (20% and 0% vs. 39% and 3%). We found that titanium alloy spinal implants experience some degree of wear and corrosion in vivo. The titanium alloy particles formed by wear exhibited good histocompatibility, not causing inflammation, foreign body reactions, or osteolysis. Therefore, spinal implants should be removed cautiously when treating titanium alloy spinal metallosis. The wear and corrosion of the implants increase with the increase in implantation time, although the screw structure does not significantly affect these changes.

Celastrol alleviates subconjunctival fibrosis induced by silicone implants mimicking glaucoma surgery.

Subconjunctival fibrosis is critical to the outcomes of several ophthalmic conditions or procedures, such as glaucoma filtering surgery. This study aimed to investigate the anti-fibrotic effect of celastrol on subconjunctival fibrosis and to further reveal the underlying mechanisms. We used celastrol-loaded nanomicelles hydrogel hybrid as a sustained-release drug. A rabbit model of subconjunctival fibrosis following silicone implantation was used for in vivo study, and TGF-ß1-induced human pterygium fibroblast (HPF) activation as an in vitro model. The effects of celastrol on inhibiting TGF-ß1-induced migration and proliferation of HPFs were evaluated by scratch wound assay and CCK-8, respectively. Immunofluorescence and western blotting were used to examine the effect of celastrol on the expression of α-SMA, collagen I, fibronectin, and the targets of the Hippo signaling pathway. We found that in vivo celastrol treatment reduced the expression of YAP and TAZ in subconjunctival tissue. Moreover, celastrol alleviated collagen deposition and subconjunctival fibrosis at 8 weeks. No obvious tissue toxicity was observed in the rabbit models. Mechanistically, celastrol significantly inhibited TGF-ß1-induced proliferation and migration of HPFs. Pretreatment of HPFs with celastrol also suppressed the TGF-ß1-induced protein expression of α-SMA, collagen I, fibronectin, TGF-ßRII, phosphorylated Smad2/3, YAP, TAZ, and TEAD1. In conclusion, celastrol effectively prevented subconjunctival fibrosis through inhibiting TGF-ß1/Smad2/3-YAP/TAZ pathway. Celastrol could serve as a promising therapy for subconjunctival fibrosis.

B-Cell Lymphoma Arising From a Nasal Implant: A Brief Clinical Study.

Continuous exposure to foreign substances initiates a sustained inflammatory reaction in the body, and subsequent chronic inflammation is recognized as one of the causes of lymphoma. Most lymphomas caused by foreign bodies are composed of 2 major phenotypes. Diffuse large B-cell lymphoma arising from metallic prosthesis, also called metallic implant-associated lymphoma and T-cell phenotype anaplastic large cell lymphoma, commonly associated with breast implants. Augmentation rhinoplasty is often performed to improve the esthetics of the nasal dorsum and various synthetic materials have been used as implants. The occurrence of lymphoma originating from a nasal implant is scarcely documented, and even more uncommon is its manifestation as epstein-barr virus (EBV)-negative extranodal marginal zone lymphoma. Here, the authors describe a rare case of B-cell lymphoma of the nose and nasolacrimal duct in a 49-year-old woman who underwent rhinoplasty with a silicone implant 20 years ago.

Etiology, pathogenesis, and management of angiosarcoma associated with implants and foreign body: Clinical cases and research updates.

Angiosarcomas are rare and highly malignant soft tissue sarcomas originating from endothelial cells lining the lymphatic or vascular system. While they predominantly emerge from (sub)cutaneous regions, occurrences have been reported throughout the body. The etiology of angiosarcoma remains elusive in most clinical cases. Nevertheless, several prognosis risk factors play a pivotal role, including chronic lymphedema, therapeutic irradiation, environmental carcinogens, familial syndromes, and the presence of foreign materials like metallic objects and biomedical implants. Despite evidence implicating retained foreign material in angiosarcoma development, understanding its prognosis and pathogenesis remains limited. The pathogenesis of angiosarcoma appears to involve a complex interplay of chronic inflammation, tissue remodeling, and genetic factors that create a conducive microenvironment for malignant transformation. Management of these sarcomas remains challenging due to their infiltrative nature owing to the high chance of metastasis and local recurrence. The primary treatment modalities currently include surgery, radiotherapy, and chemotherapy, but recent advances in targeted immunotherapy and gene therapy hold promise for more effective approaches. This comprehensive review delves into the potential etiological and pathogenic roles of foreign materials, such as metallic objects, biomedical implants, and biomaterials, in the development of angiosarcoma. Further research into the underlying molecular mechanisms could provide valuable insights for tailored management and developing novel targeted therapeutic strategies.

Metal implant allergy: A retrospective cohort analysis at a university allergy practice.

Background: Concern of metal sensitization in pre- and postsurgical evaluation is growing, with the recent guidelines remaining the criterion standard for consideration of patch testing. Information remains scarce on surgical screening in the groups of patients who reported a history of metal sensitivity versus those with no reported history. Objective: The objective of this study was to assess the utility of patch testing in surgical candidates based on reported metal allergy history. The secondary objective was to evaluate the utility and outcomes in postsurgical patch testing. Methods: Nine hundred and thirty-one patient charts of patients with the diagnosis of "contact dermatitis" who underwent an evaluation at a single allergy clinic site between January 2013 and December 2022 were identified and reviewed as part of a retrospective chart review study. Patients were included in subgroups based on the time of patch testing and history of reported metal allergy. Results: In all, 67 patients underwent patch testing, 10 (14.9%) of whom were surgical candidates without a history of metal sensitivity, 31 (46.2%) of whom were surgical candidates with a history of metal sensitivity, and 26 (38.8%) of whom were postsurgical patients. Twenty-nine (43.3%) of patients had positive patch testing results, with only one (10%) in the presurgical group, 17 (54.8%) in the presurgical with a history of metal sensitivity, and 11 (42.3%) in the postsurgical group. Zero patients in our cohort without metal sensitivity who were undergoing the Nuss procedure had positive reactions on patch testing, whereas two of four (50%) with reported metal sensitivity who were undergoing the Nuss procedure had positive relevant metal reactions. Conclusion: Ambiguity in the utility of patch testing for surgical decision making remains, despite common utilization. Recent guidelines along with coordination of care among the surgeon, allergist, and patient remains the criterion standard of care.

Bronchial Valves for Persistent Air Leak: A Systematic Review and Meta-analysis.

BACKGROUND: Patients with persistent air leak (PAL) pose a therapeutic challenge to physicians, with prolonged hospital stays and high morbidity. There is little evidence on the efficacy and safety of bronchial valves (BV) for PAL. METHODS: We systematically searched the PubMed and Embase databases to identify studies evaluating the efficacy and safety of BV for PAL. We calculated the success rate (complete resolution of air leak or removal of intercostal chest drain after bronchial valve placement and requiring no further procedures) of BV for PAL in individual studies. We pooled the data using a random-effects model and examined the factors influencing the success rate using multivariable meta-regression. RESULTS: We analyzed 28 observational studies (2472 participants). The pooled success rate of bronchial valves in PAL was 82% (95% confidence intervals, 75 to 88; 95% prediction intervals, 64 to 92). We found a higher success rate in studies using intrabronchial valves versus endobronchial valves (84% vs. 72%) and in studies with more than 50 subjects (93% vs. 77%). However, none of the factors influenced the success rate of multivariable meta-regression. The overall complication rate was 9.1% (48/527). Granulation tissue was the most common complication reported followed by valve migration or expectoration and hypoxemia. CONCLUSION: Bronchial valves are an effective and safe option for treating PAL. However, the analysis is limited by the availability of only observational data.

An Update on Implant-Associated Malignancies and Their Biocompatibility.

Implanted medical devices are widely used across various medical specialties for numerous applications, ranging from cardiovascular supports to orthopedic prostheses and cosmetic enhancements. However, recent observations have raised concerns about the potential of these implants to induce malignancies in the tissues surrounding them. There have been several case reports documenting the occurrence of cancers adjacent to these devices, prompting a closer examination of their safety. This review delves into the epidemiology, clinical presentations, pathological findings, and hypothesized mechanisms of carcinogenesis related to implanted devices. It also explores how the surgical domain and the intrinsic properties and biocompatibility of the implants might influence the development of these rare but serious malignancies. Understanding these associations is crucial for assessing the risks associated with the use of medical implants, and for developing strategies to mitigate potential adverse outcomes.

A literature review and expert consensus statement on diagnostics in suspected metal implant allergy.

BACKGROUND: Although rare, allergic reactions to metal implants represent a diagnostic challenge in view of missing guidelines. OBJECTIVES: To develop an European expert consensus on characteristics of metal allergy reactions and the utility of various diagnostic tools in suspected metal implant allergy. METHODS: A nominal group technique (NGT) was applied to develop consensus statements. Initially an online literature database was created on a secure server to enable a comprehensive information. Twenty-three statements were formulated on potential aspects of metal implant allergy with a focus on diagnostics and grouped into five domains. For the consensus development, the panel of 12 experts initially did refine and reformulate those statements that were ambiguous or had unclear wording. By face-to-face (9/12) or virtual participation (3/12), an anonymous online voting was performed. RESULTS: Consensus (≥80% of agreement) was reached in 20/23 statements. The panel agreed that implant allergy despite being rare should be considered in case of persistent unexplained symptoms. It was, however, recommended to allow adequate time for resolution of symptoms associated with healing and integration of an implant. Obtaining questionnaire-aided standardized medical history and standardized scoring of patient outcomes was also considered an important step by all experts There was broad consensus regarding the utility/performance of patch testing with additional late reading. It was recognized that the lymphocyte transformation test (LTT) has to many limitations to be generally recommended. Prior to orthopaedic implant, allergy screening of patients without a history of potential allergy to implant components was not recommended. CONCLUSIONS: Using an expert consensus process, statements concerning allergy diagnostics in suspected metal implant allergy were created. Areas of nonconsensus were identified, stressing uncertainty among the experts around topics such as preoperative testing in assumed allergy, histological correlate of periimplant allergy and in vitro testing, which underscores the need for further research.

Protecting Orthopaedic Implants from Infection: Antimicrobial Peptide Mel4 Is Non-Toxic to Bone Cells and Reduces Bacterial Colonisation When Bound to Plasma Ion-Implanted 3D-Printed PAEK Polymers.

Even with the best infection control protocols in place, the risk of a hospital-acquired infection of the surface of an implanted device remains significant. A bacterial biofilm can form and has the potential to escape the host immune system and develop resistance to conventional antibiotics, ultimately causing the implant to fail, seriously impacting patient well-being. Here, we demonstrate a 4 log reduction in the infection rate by the common pathogen S. aureus of 3D-printed polyaryl ether ketone (PAEK) polymeric surfaces by covalently binding the antimicrobial peptide Mel4 to the surface using plasma immersion ion implantation (PIII) treatment. The surfaces with added texture created by 3D-printed processes such as fused deposition-modelled polyether ether ketone (PEEK) and selective laser-sintered polyether ketone (PEK) can be equally well protected as conventionally manufactured materials. Unbound Mel4 in solution at relevant concentrations is non-cytotoxic to osteoblastic cell line Saos-2. Mel4 in combination with PIII aids Saos-2 cells to attach to the surface, increasing the adhesion by 88% compared to untreated materials without Mel4. A reduction in mineralisation on the Mel4-containing surfaces relative to surfaces without peptide was found, attributed to the acellular portion of mineral deposition.

Severe Hemodynamic Collapse During Humerus Stabilization with Photodynamic Implant: A Report of Two Cases.

CASE: We present 2 cases of severe hemodynamic collapse during prophylactic stabilization of impending pathologic humerus fractures using a photodynamic bone stabilization device. Both events occurred when the monomer was infused under pressure into a balloon catheter. CONCLUSION: We suspect that an increase in intramedullary pressure during balloon expansion may cause adverse systemic effects similar to fat embolism or bone cement implantation syndrome. Appropriate communication with the anesthesia team, invasive hemodynamic monitoring, and prophylactic vent hole creation may help mitigate or manage these adverse systemic effects.

Ventriculo-gallbladder shunt: case series and literature review.

BACKGROUND: The ventriculoperitoneal shunt (VPS) is the gold-standard surgical technique to treat hypertensive hydrocephalus; however, it may fail in 20 to 70% of cases. The present study shows an alternative for patients with contraindications to VPS. METHODS: A case series of nine patients. The medical records of all patients under 17 years of age who underwent ventriculo-gallbladder (VGB) shunt at a pediatric hospital from January 2014 to October 2022 were reviewed. RESULTS: There were 6 (66.7%) males and 3 (33.3%) females. The average age of 73.6 months or 6.1 years at the time of surgery. They had undergone, on average, 5.1 VPS reviews before the VGB shunt. Five (55.5%) had complications of VGB shunt: infection (11.1%), atony (11.1%), hypodrainage (11.1%), and ventriculoenteric fistula (22.2%); all these patients got better at surgical reapproach, and in two of them, the VGB shunt was re-implanted. CONCLUSION: This case series shows a lower risk of death and a similar risk of complications compared to other alternative shunts. This article spotlighted VGB as a viable alternative when VPS fails or has contraindications.

Instrumentation failure following pediatric spine deformity growth-sparing surgery using traditional growing rods or vertical expandable prosthetic titanium ribs.

BACKGROUND: Instrumentation failure (IF) is a major complication associated with growth-sparing surgery for pediatric spinal deformities; however, studies focusing on IF following each surgical procedure are lacking. We aimed to evaluate the incidence, timing, and rates of unplanned return to the operating room (UPROR) associated with IF following each surgical procedure in growth-sparing surgeries using traditional growing rods (TGRs) and vertical expandable prosthetic titanium ribs (VEPTRs). METHODS: We reviewed 1,139 surgical procedures documented in a Japanese multicenter database from 2015 to 2017. Of these, 544 TGR and 455 VEPTR procedures were included for evaluation on a per-surgery basis. IF was defined as the occurrence of an implant-related complication requiring revision surgery. RESULTS: The surgery-based incidences of IF requiring revision surgery in the TGR and VEPTR groups were 4.3% and 4.0%, respectively, with no significant intergroup difference. Remarkably, there was a negative correlation between IF incidence per surgical procedure and the number of lengthening surgeries in both groups. In addition, rod breakage in the TGR group and anchor-related complications in the VEPTR group tended to occur relatively early in the treatment course. The surgery-based rates of UPROR due to IF in the TGR and VEPTR groups were 2.0% and 1.5%, respectively, showing no statistically significant difference. CONCLUSIONS: We found that IF, such as anchor related-complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries. This finding may help in patient counseling and highlights the importance of close postoperative follow-up to detect IF and improve outcomes.

Decoding the "Fingerprint" of Implant Materials: Insights into the Foreign Body Reaction.

Foreign body reaction (FBR) is a prevalent yet often overlooked pathological phenomenon, particularly within the field of biomedical implantation. The presence of FBR poses a heavy burden on both the medical and socioeconomic systems. This review seeks to elucidate the protein "fingerprint" of implant materials, which is generated by the physiochemical properties of the implant materials themselves. In this review, the activity of macrophages, the formation of foreign body giant cells (FBGCs), and the development of fibrosis capsules in the context of FBR are introduced. Additionally, the relationship between various implant materials and FBR is elucidated in detail, as is an overview of the existing approaches and technologies employed to alleviate FBR. Finally, the significance of implant components (metallic materials and non-metallic materials), surface CHEMISTRY (charge and wettability), and physical characteristics (topography, roughness, and stiffness) in establishing the protein "fingerprint" of implant materials is also well documented. In conclusion, this review aims to emphasize the importance of FBR on implant materials and provides the current perspectives and approaches in developing implant materials with anti-FBR properties.

Titanium Allergy: A Retrospective Review of 166 Patch Tested Patients.

Background: Although most patients do not develop hypersensitivity reactions to metals in implanted devices, when they do occur, significant morbidity can result. Titanium-based systems are often considered as an alternative option in metal-allergic patients; however, there are few studies published on titanium allergy and allergic reactions to titanium in implants may be overlooked in clinical practice. Methods: Our aim was to further characterize a single institution's experience with titanium patch testing and evaluation of titanium allergy. We performed a retrospective medical record review of 166 patients evaluated for titanium contact allergy between January 2018-August 2023. Of the 166 patients in our cohort, 67 were referred for pre-implant patch testing and 64 for post-implant patch testing; 35 were tested for reasons unrelated to an implant. Results: Twenty-six of the 166 patients were PTP to titanium (15.7% positive rate). Titanium PTP rates were higher for post-implant cases (28.1%, 18/64) compared to pre-implant cases (6.0%, 4/67) (χ2 9.97, p = 0.002). Among 18 titanium PTPs identified for the 64 post-implant cases, 8 were likely relevant, 8 possibly relevant, and 2 not likely relevant. Conclusions: Further studies should be performed to evaluate the incidence of allergy to titanium implants and to continue surveillance of changes in sensitization rates.