Metallosis is commonly associated with magnetically controlled growing rods; results from an independent multicentre explant database.

PURPOSE: Determine the incidence of metallosis around MAGEC rods. METHODS: A multicentre explant database was searched to identify cases with complete intraoperative findings at rod removal. Surgeons removing rods detailed the presence or absence of tissue metallosis associated with rods. More recently surgeons measured the 'length' of tissue metallosis. Prior to rod disassembly, the majority underwent testing with an external remote controller (ERC). The impact of clinical and explant variables on metallosis was assessed. RESULTS: Sixty-six cases were identified. Mean age at insertion was 8.1 ± 2.3 years with mean duration of implantation 37.6 ± 15.1 months. Tissue metallosis was noted at revision surgery in 52/66 cases (79%). Metallosis was noted more commonly when rods were removed during fusion surgery than rod removal/exchange (97% vs. 58% (p = < 0.01)). The mass at insertion was greater in cases with metallosis (25.9 ± 7.8 kg vs. 21.1 ± 6.2 kg, p = 0.04). Length of tissue metallosis was reported for 45 rods, median 9 cm (range 1-25). Metallosis was noted in 43/59 (73%) rods that produced no force and 22/30 (73%) rods that produced some force on ERC activation (p = 0.96). Wear debris was found within the actuator in all rods, and all but 3 rods had damaged O-rings. CONCLUSION: MAGEC rods are associated with tissue metallosis in the majority of cases. It is seen with functional rods as well as failed rods and appears related to wear debris within the actuator and high rates of O-ring failure. Until the implications of metal debris in children are known, we urge caution with the use of this implant.

The composition of immune cells serves as a predictor of adaptive immunity in a cohort of 50- to 74-year-old adults.

Influenza causes significant morbidity and mortality annually. Although vaccination offers a considerable amount of protection, it is far from perfect, especially in aging populations. This is due to age-related defects in immune function, a process called immunosenescence. To date, there are no assays or methods to predict or explain variations in an individual's level of response to influenza vaccination. In this study, we measured levels of several immune cell subsets at baseline (Day 0) and at Days 3 and 28 post-vaccination using flow cytometry. Statistical modelling was performed to assess correlations between levels of cell subsets and Day 28 immune responses - haemagglutination inhibition (HAI) assay, virus neutralizing antibody (VNA) assay, and memory B cell ELISPOT. Changes in several groups of cell types from Day 0 to Day 28 and Day 3 to Day 28 were found to be significantly associated with immune response. Baseline levels of several immune cell subsets, including B cells and regulatory T cells, were able to partially explain variation in memory B-cell ELISPOT results. Increased expression of HLA-DR on plasmacytoid dendritic cells after vaccination was correlated with increased HAI and VNA responses. Our data suggest that the expression of activation markers (HLA-DR and CD86) on various immune cell subsets, as well as the relative distribution of cell subsets, both have value in predicting immune responses to influenza vaccination in older individuals.

The NuVasive MAGEC Rod Urgent Field Safety Notice Concerning Locking Pin Fracture: How Does Data From an Independent Explant Center Compare?

STUDY DESIGN: Analysis of explanted MAGnetic Expansion Control (MAGEC) growing rods. OBJECTIVE: The aim of this study was to quantify the rate of locking pin breakage in explanted MAGEC rods and compare with the manufacturer's data. SUMMARY OF BACKGROUND DATA: On June 25, 2019, NuVasive released an Urgent Field Safety Notice stating that MAGEC rods manufactured before March 26, 2015 had a higher than expected locking pin breakage rate of 5%. For rods made on or after that date, no pin breakages had occurred. METHODS: From our independent explant database of 139 explanted MAGEC rods supplied from 10 UK spinal centers (Belfast, Bristol, Birmingham, Edinburgh, Exeter, Leeds, Newcastle, Nottingham, Oxford, and Sheffield) and one Danish center (Aarhus), we divided the rods into those manufactured before March 26, 2015, and those manufactured on or after that date. MAGEC rods were cut open to fully assess internal components including locking pins. From each of the two cohorts, 10 locking pins were selected at random and their diameters were measured using a micrometer. RESULTS: One hundred and five explanted MAGEC rods were made before March 26, 2015 and could be disassembled to allow the locking pin to be examined. Fifty-nine percent (62/105) of these locking pins had fractured. For the MAGEC rods manufactured on or after March 26, 2015, 21% (6/29) were found to have fractured locking pins. Locking pins in MAGEC rods made on or after March 26, 2015 were of a stronger material and a larger diameter. CONCLUSION: Fifty-nine percent of the locking pins in MAGEC rods manufactured before March 26, 2015 had fractured, far greater than the 5% stated in the Urgent Field Safety Notice. Locking pin fracture still occurred in MAGEC rods manufactured on or after that date, in 21% of cases. This contrasted with the 0% reported by the manufacturer. LEVEL OF EVIDENCE: 4.

Spinal Lengthening With Magnetically Controlled Growing Rods: Data From the Largest Series of Explanted Devices.

STUDY DESIGN: Laboratory analysis of explanted MAGnetic Expansion Control (MAGEC) rods. OBJECTIVE: The aim of this study was to identify the in vivo lengthening of MAGEC rods. SUMMARY OF BACKGROUND DATA: Little data is available regarding the lengthening achieved by MAGEC rods. METHODS: Cases were identified from the largest series of independently analyzed explanted MAGEC rods. The in vivo growth of rods was determined by the distance between the first "growth mark" and the actuator. The instrumented spinal lengthening was calculated for each construct. Constructs were considered functional if all rods could lengthen with external remote controller activation and no rods were "telescoping". RESULTS: Fifty-five MAGEC constructs (99 rods) from 53 patients treated at 10 centers were included. The mean age at insertion was 8.5 years with rods implanted a mean of 35 months. Sixty rods were suitable for analysis with mean lengthening 21.7 mm, 8.9 mm/year. Of these 60 rods, three were maximally distracted. Mean instrumented spinal lengthening for 38 suitable cases was 22.1 mm, 8.4 mm/year. This was positively correlated with the duration of implantation (r = 0.34, P = 0.04) but negatively with patient age at insertion (r = -0.35, P = 0.03). The rate of instrumented spinal lengthening was negatively correlated with duration of implantation (r = -0.47, P = 0.004). Of 55 constructs, 34 were nonfunctional at time of removal with nine functional and 12 indeterminate. Functional constructs had been implanted significantly less time (20.0 vs. 39.7 months, P < 0.001) and lengthened less than those nonfunctional (12.3 mm vs. 23.3 mm, P = 0.04). CONCLUSION: This multicenter explant study represents the largest cohort managed with MAGEC rods reported. Rods are very rarely removed having fully lengthened with mean instrumented spinal growth of 22 mm over the implant's life. This may be explained by a high rate of lengthening mechanism failure in received rods after around 3 years in vivo. Our findings question the effectiveness of the MAGEC system and mandate urgent comparative clinical studies. LEVEL OF EVIDENCE: 4.

Force Testing of Explanted Magnetically Controlled Growing Rods.

STUDY DESIGN: Laboratory analysis of explanted MAGnetic Expansion Control (MAGEC) growing rods. OBJECTIVE: The aim of this study was to measure the force produced by explanted MAGEC rods compared with new rods and assess the influence of clinical variables. SUMMARY OF BACKGROUND DATA: MAGEC rods are increasingly used in early-onset scoliosis. Some data are available describing the structure of explanted MAGEC rods, but to date, no study has assessed their function. METHODS: Explanted MAGEC rods were received from seven UK and one Danish center. The force produced by explanted rods on activation with the external remote controller was measured using a dedicated jig. Forces were compared with two unused rods as well as the manufacturer's defined standard (42 Ibf). Clinical variables were collected from contributing centers where possible and correlated with the force measurements. RESULTS: Forty-five MAGEC rods from 25 cases were received for analysis. The mean age at insertion was 8.6 years and rods were in vivo for a mean of 2.7 years in predominantly dual rod constructs. Two unused MAGEC rods produced a mean force of 45.3 (0.25) and 50.2 (1.4) Ibf, above the manufacturer's stated standard. Of the 45 explanted rods, 10 (22%) produced force greater or equal to manufacturer's standard, mean 46.7 (2.7) Ibf. Six rods (13%) produced some force but less than the manufacturer's standard, mean 34.8 (3.6) Ibf. Twenty-nine rods (64%) produced no force. The duration the rods were in vivo was significantly negatively correlated with the force produced on testing (r = -0.63, P < 0.005). Of the 12 rods implanted longer than 38 months, none produced any force. CONCLUSION: This is the first study of the force, and hence likely function, of explanted MAGEC rods. The majority of explanted rods produced no force, while others produced reduced force. These findings raise questions regarding the longevity of the implant and further clinical outcome studies are recommended. LEVEL OF EVIDENCE: 4.

Analysis of Explanted Magnetically Controlled Growing Rods From Seven UK Spinal Centers.

STUDY DESIGN: Analysis of explanted MAGnetic Expansion Control (MAGEC) growing rods. OBJECTIVE: To analyze explanted MAGEC rods used in management of early onset scoliosis and identify the mode of failure in such cases. SUMMARY OF BACKGROUND DATA: Magnetically controlled growing rods are increasingly used as the option of choice for early onset scoliosis. However, being more complex than conventional growing rods they are perhaps more likely to succumb to multifarious failure modes. In addition, metallosis has been reported around failed MAGEC rods. METHODS: Explanted MAGEC rods from seven UK spinal centers were obtained for independent analysis. Thirty-four MAGEC rods, from 18 children, explanted for reasons including failure of rod lengthening and maximum rod distraction reached, were cut open to allow internal components to be evaluated and assessed. RESULTS: Externally, all MAGEC rods showed localized marks, which were termed "growth marks" as they indicated growth of the rod in vivo, on the extending bar component. After cutting open, titanium wear debris was found inside all 34 (100%) MAGEC rods. Ninety-one percent (31/34) of MAGEC rods showed measurable wear of the extending bar, towards the magnet end. Substantial damage to the radial bearing was seen inside 74% (25/34) of MAGEC rods while O-ring seal failure was seen in 53% (18/34) of cases. In 44% (15/34) of MAGEC rods the drive pin was fractured but this was felt to be an effect of rod failure, not a cause. CONCLUSION: The combination of high volumes of titanium wear debris alongside O-ring seal damage likely accounts for the metallosis reported clinically around some MAGEC rods. Based on this explant data, a failure mechanism in MAGEC rods due to the natural off axis loading in the spine was proposed. This is the largest data set reporting a complete analysis of explanted MAGEC rods to date. LEVEL OF EVIDENCE: 4.

Characterization of rubella-specific humoral immunity following two doses of MMR vaccine using proteome microarray technology.

INTRODUCTION//BACKGROUND: The lack of standardization of the currently used commercial anti-rubella IgG antibody assays leads to frequent misinterpretation of results for samples with low/equivocal antibody concentration. The use of alternative approaches in rubella serology could add new information leading to a fuller understanding of rubella protective immunity and neutralizing antibody response after vaccination. METHODS: We applied microarray technology to measure antibodies to all rubella virus proteins in 75 high and 75 low rubella virus-specific antibody responders after two MMR vaccine doses. These data were used in multivariate penalized logistic regression modeling of rubella-specific neutralizing antibody response after vaccination. RESULTS: We measured antibodies to all rubella virus structural proteins (i.e., the glycoproteins E1 and E2 and the capsid C protein) and to the non-structural protein P150. Antibody levels to each of these proteins were: correlated with the neutralizing antibody titer (p<0.006); demonstrated differences between the high and the low antibody responder groups (p<0.008); and were components of the model associated with/predictive of vaccine-induced rubella virus-specific neutralizing antibody titers (misclassification error = 0.2). CONCLUSION: Our study supports the use of this new technology, as well as the use of antibody profiles/patterns (rather than single antibody measures) as biomarkers of neutralizing antibody response and correlates of protective immunity in rubella virus serology.

Population estimates of Thiobacillus thioparus in composting biofilters by PCR analysis.

A direct most-probable-number polymerase chain reaction method (MPN-PCR) was used to monitor populations of Thiobacillus thioparus in compost biofilters used to treat air contaminated with dymethyl disulphide and ammonia. The PCR method quantified this bacterium at numbers ranging from log 2 to log 8 cells per gram of biofilter media.

Hyperfractionated Accelerated Radiotherapy (HART) with maintenance chemotherapy for metastatic (M1-3) Medulloblastoma--a safety/feasibility study.

BACKGROUND AND PURPOSE: To evaluate feasibility and toxicity of Hyperfractionated Accelerated Radiotherapy (HART) 1.24Gy b.i.d. followed by chemotherapy for M1-3 Medulloblastoma (MB). The aim of HART was to use hyperfractionation to improve therapeutic ratio combined with acceleration to minimise tumour cell repopulation during radiotherapy (RT). MATERIALS AND METHODS: Between February 2002 and May 2008, 34 eligible patients (22 male, 12 female) aged 3-15years (median 7) with metastatic MB (M1-9; M2-3, M3-22) received HART with a craniospinal radiotherapy (CSRT) dose of 39.68Gy followed by 22.32Gy boost to the whole posterior fossa and 9.92Gy metastatic boosts. The 8th and subsequent patients received vincristine (VCR) 1.5mg/m(2) weekly×8 doses over 8weeks starting during the 1st week of RT. Maintenance chemotherapy comprised 8 six-weekly cycles of VCR 1.5mg/m(2) weekly×3, CCNU 75mg/m(2) and cisplatin 70mg/m(2). RESULTS: Median duration of HART was 34days (range 31-38). Grade 3-4 toxicities included mucositis (8), nausea (10), anaemia (5), thrombocytopaenia (2), leucopaenia (24). With 4.5-year median follow-up, 3-year EFS and OS were 59% and 71%, respectively. Of 10 relapses, 1 was outside the central nervous system (CNS), 1 posterior fossa alone and 8 leptomeningeal with 3 also associated with posterior fossa. CONCLUSION: HART with or without VCR was well tolerated and may have a place in the multi-modality management of high-risk MB.

Thoracic vertebral osteomyelitis secondary to chronic esophageal perforation.

BACKGROUND CONTEXT: Osteomyelitis secondary to perforation of the esophagus is a rare condition. Thoracic osteomyelitis after chronic esophageal perforation has never been described in the literature. PURPOSE: We report a case of vertebral osteomyelitis resulting from a chronic esophageal perforation. STUDY DESIGN/SETTING: Case report/University hospital. METHODS: A 52-year-old woman presented with dysphagia, severe mid back, and epigastric pain over a 6-week period. Endoscopic and radiological investigations revealed the presence of a paraspinal inflammatory mass protruding into the posterior esophageal wall. Two weeks after admission, the patient developed septic complications which required surgical intervention. This revealed the presence of an esophageal perforation and osteomyelitis of the T4-T5 and T7-T8 vertebrae. After T-tube closure of the esophageal perforation along with surgical debridement of the vertebrae and a 6-week course of antibiotics, the patient made a sound recovery. However, there was persistence of back pain with exaggerated thoracic spine kyphosis at T7-T8 which needed thoracic spine stabilization with pedicle screw instrumentation and fusion. RESULTS: This treatment led to complete recovery with no recurrence of symptoms at 8-months' follow-up. CONCLUSIONS: To date this is the first case of thoracic osteomyelitis secondary to a chronic esophageal perforation to be reported in the literature. A high index of suspicion of this diagnosis is warranted in patients who present with similar clinical and radiological findings to enable prompt diagnosis and avoid the high mortality of esophageal perforation.

Correction of neuromuscular scoliosis in patients with preexisting respiratory failure.

STUDY DESIGN: A prospective observational study in scoliosis patients who were on noninvasive night ventilation for respiratory failure. OBJECTIVE: To report the results of spinal deformity correction in a group of patients with progressive scoliosis and rare forms of muscular dystrophy/myopathy with respiratory failure who were on nocturnal ventilatory support at the time of surgery. SUMMARY OF BACKGROUND DATA: This is the first study on the results of deformity correction in a series of patients on ventilatory support. MATERIALS AND METHODS: Eight patients (6 males, 2 females) presented with progressive scoliosis and respiratory failure. The mean age at surgery was 12 years (range, 8-15 years). The mean follow-up was 48 months (range, 12-80 months). Outcome measures include lung function (spirometry), overnight pulse oximetry, Cobb angles, duration of stay in Intensive care (ICU), and the total hospital stay. RESULTS: The mean stay in the ICU was 2.7 days (range, 2-5 days). The mean hospital stay was 14.2 days (range, 10-21 days). The mean preoperative Cobb angle was 70.2 degrees (55 degrees -85 degrees ). This changed to 32 degrees (16 degrees -65 degrees ) after surgery (P = 0.0002). The mean vital capacity at the time of surgery was 20% (range, 13%-28%). The mean vital capacity of patients at last follow-up was 18% (range, 10%-31%). The desaturation noted on the preventilation overnight oximetry was reversed by nocturnal ventilation. All patients recovered well following surgery with no major cardiac or pulmonary complications. CONCLUSION: Patients with preexisting respiratory failure on nocturnal noninvasive ventilation can be safely operated for deformity correction. This can help to significantly improve their quality of life.