Comparison of major spine navigation platforms based on key performance metrics: a meta-analysis of 16,040 screws.

PURPOSE: The objective of this meta-analysis is to compare available computer-assisted navigation platforms by key performance metrics including pedicle screw placement accuracy, operative time, neurological complications, and blood loss. METHODS: A systematic review was conducted using major databases for articles comparing pedicle screw accuracy of computer-assisted navigation to conventional (freehand or fluoroscopy) controls via post-operative computed tomography. Outcome data were extracted and pooled by random-effects model for analysis. RESULTS: All navigation platforms demonstrated significant reduction in risk of breach, with Stryker demonstrating the highest accuracy compared to controls (OR 0.16 95% CI 0.06 to 0.41, P < 0.00001, I2 = 0%) followed by Medtronic. There were no significant differences in accuracy or most surgical outcome measures between platforms; however, BrainLab demonstrated significantly faster operative time compared to Medtronic by 30 min (95% CI - 63.27 to - 2.47, P = 0.03, I2 = 74%). Together, there was significantly lower risk of major breach in the navigation group compared to controls (OR 0.42, 95% CI 0.27-0.63, P < 0.0001, I2 = 56%). CONCLUSIONS: When comparing between platforms, Stryker demonstrated the highest accuracy, and Brainlab the shortest operative time, both followed by Medtronic. No significant difference was found between platforms regarding neurologic complications or blood loss. Overall, our results demonstrated a 60% reduction in risk of major breach utilizing computer-assisted navigation, coinciding with previous studies, and supporting its validity. This study is the first to directly compare available navigation platforms offering insight for further investigation and aiding in the institutional procurement of platforms. LEVEL 3 EVIDENCE: Meta-analysis of Level 3 studies.

Subsidence of a Single-Taper Femoral Stem in Primary Total Hip Arthroplasty: Characterization, Associated Factors, and Sequelae.

BACKGROUND: We characterized subsidence of an uncemented single-taper femoral stem in primary total hip arthroplasty (THA), determined factors associated with subsidence, and evaluated the impact of subsidence on outcome. METHODS: This retrospective study included 502 primary THAs performed using a single-taper stem in Dorr type-A and type-B femora between 2014 and 2018. Subsidence was measured based on distance from the greater trochanter to stem shoulder on calibrated X-rays. Demographics, case-specific data, and outcomes were collected. Changes in subsidence and variables associated with subsidence were determined. RESULTS: Stem subsidence was 1.5 ± 2.3 mm, 1.6 ± 2.0 mm, 2.0 ± 2.6 mm, 2.3 ± 2.3 mm, 2.6 ± 2.5 mm, and 2.7 ± 3.0 mm at 6 weeks, 3 months, 6 months, 1 year, 2 years, and ≥3 years from THA, respectively. Subsidence across all patients at final mean follow-up of 24 months (range, 1 to 101 months) was 2.2 ± 2.6 mm. Pairwise comparison demonstrated that subsidence occurred predominantly within the first 6 months. Significant subsidence (≥5 mm) occurred in 17.3% and was associated with a body mass index (BMI) ≥25 (P = .04). Dorr type, age, sex, and American Society of Anesthesiologists class were not associated with subsidence. There were 2 patients (0.4%) who underwent a revision that could be attributed to subsidence. There was no association between subsidence and pain, limp, need for ambulatory aid, or analgesic use. CONCLUSION: In primary THAs performed using a single-taper prosthesis, average subsidence was 2.2 mm and significant subsidence occurred in 17.3%. Patient BMI was associated with subsidence. Revision surgery related to subsidence was infrequent (0.4%).

Expression of Chondrogenic Potential Markers in Cultured Chondrocytes from the Human Knee Joint.

OBJECTIVES: While substantial progress has been made in engineering cartilaginous constructs for animal models, further research is needed to translate these methodologies for human applications. Evidence suggests that cultured autologous chondrocytes undergo changes in phenotype and gene expression, thereby affecting their proliferation and differentiation capacity. This study was designed to evaluate the expression of chondrogenic markers in cultured human articular chondrocytes from passages 3 (P3) and 7 (P7), beyond the current clinical recommendation of P3. METHODS: Cultured autologous chondrocytes were passaged from P3 up to P7, and quantitative polymerase chain reaction (qPCR) was used to assess mRNA expression of chondrogenic markers, including collagen type I (COLI), collagen type II (COLII), aggrecan (AGG), bone morphogenetic protein 4 (BMP4), transcription factor SOX-9 (SOX9), proteoglycan 4 (PGR4), and transformation-related protein 53 (p53), between P3 and P7. RESULTS: Except for AGG, no significant differences were found in the expression of markers between passages, suggesting the maintenance of chondrogenic potential in cultured chondrocytes. Differential expression identified between SOX9 and PGR4, as well as between COLI and SOX9, indicates that differences in chondrogenic markers are present between age groups and sexes, respectively. CONCLUSIONS: Overall, expression profiles of younger and male chondrocytes exhibit conversion of mature cartilage characteristics compared to their counterparts, with signs of dedifferentiation and loss of phenotype within-group passaging. These results may have implications in guiding the use of higher passaged chondrocytes for engineering constructs and provide a foundation for clinical recommendations surrounding the repair and treatment of articular cartilage pathology in both sexes.

BEAT-IT: A de-novo cardiac screening programme in Maltese adolescents.

AIMS: Sudden cardiac death (SCD) in young individuals is often unexpected, provoking substantial emotional stress for family and friends of the deceased. Cardiac screening may identify individuals who harbour disorders linked to SCD. The feasibility and diagnostic yield of a nationwide cardiac screening programme in adolescents has never been explored. METHODS: All individuals eligible for cardiac screening (students aged 15 years) were systematically invited to enrol. Students were provided with a health questionnaire. ECGs were acquired at school. A physician led consultation was carried out on site. Participants with an abnormal screen were then referred for secondary evaluation to the nation's tertiary centre. Feasibility criteria included a) participation rate >60%, b) adherence to secondary evaluation >80%, and c) cost per individual screened equating to <€100. The diagnostic yield was also evaluated. RESULTS: At the end of enrolment, 2708 students gave consent (mean 15 years, 50.4% male), equating to 67.9% of the eligible cohort. Overall, 109 participants (4.0%) were referred for further evaluation. An abnormal electrocardiogram (ECG) was the most common reason for referral (3.7%). Fifteen individuals (0.6%) were diagnosed with a cardiac condition. Nine (0.3%) had a condition linked to SCD (n = 1 Long-QT syndrome, n = 1 Hypertrophic Cardiomyopathy, n = 5 Wolff-Parkinson White, n = 2 coronary anomalies). The yield was similar in athletes and non-athletes (p = 0.324). The cost per cardiac individual screened equated to €51.15. CONCLUSION: A nationwide systematic cardiac screening programme for adolescent athletes and non-athletes is feasible and cost-efficient, provided that responsible centres have the appropriate infrastructure.

The juvenile ECG pattern in adolescent athletes and non-athletes in a national cardiac screening program (BEAT-IT).

BACKGROUND: Anterior T wave inversion (TWI) is frequent in healthy adolescent individuals (juvenile ECG pattern), normalising after puberty. Its clinical implications are uncertain. AIM: This study assessed a) national prevalence of anterior TWI, b) ST segment morphology, c) proportion of individuals with a juvenile ECG pattern whose ECG normalises and d) factors predicting TWI persistence >16 years. METHODS: Adolescents (mean 15y) in Malta were systematically invited to enrol in a cardiac screening program. Subjects completed a health questionnaire and an ECG at their school. Participants with TWI were labelled as TWI in V1-V2 or extended TWI (V1-V3/4). The latter were followed at 1 year with a repeat ECG. Those with persistent extended anterior TWI were offered evaluation and surveillance. RESULTS: The prevalence of isolated anterior TWI was 5.0%, commoner in females (6.3%) independent of athletic ability. Extended TWI was commoner in female athletes (4.2%, non-athletes 2.1%). Females often had shallow TWI without overt ST segment abnormalities. Deep TWI and ST segment changes were more frequent in males. Only 0.2% of cases persisted ≥16 years of age. ST segment characteristics were not able to predict T wave normalisation. No events took place during follow up (40 ± 9 months). CONCLUSION: Anterior TWI is a frequent phenomenon in adolescents, especially in females. Female athletes are also more likely to have extended anterior TWI. Only 0.2% of cases have persistent anterior TWI at 16 years of age. Chest wall anatomy may explain this phenomenon in females. It is uncommon in males, hence why surveillance is more prudent.

A case report of profound atrioventricular block in an endurance athlete: how far do you go?

Background: Athletes presenting with 1st-degree atrioventricular block (AVB) on 12-lead electrocardiogram (ECG) may present a diagnostic conundrum, especially when significantly prolonged and associated with higher degrees of block. A pragmatic stepwise approach to the evaluation of these patients is, therefore, crucial. Case summary: A 19-year-old waterpolo player was referred for assessment of a 1st-degree heart block and one isolated episode of syncope. All other cardiac investigations were within normal limits except for a 24-h ambulatory ECG which showed Mobitz 1 AVB and episodes of 2:1 block occurring in the context of Wenchebach. An electrophysiological study (EPS) was performed which effectively excluded infranodal conductive tissue disease, confirming physiological intranodal block. Discussion: The increase in vagal tone is one of the physiological adaptations to an increased demand in cardiac output in athletes, which explains the presence of 1st-degree AVB in up to 7.5% of athletes. The presence of 2:1 AVB on 24 h ECG raises doubts whether the 1st-degree AVB on resting ECG is pathological or physiological, especially considering this particular patient had suffered an episode of syncope. When this diagnostic uncertainty persists despite non-invasive investigations, including cardiopulmonary exercise testing, invasive EPS may be required to assess the refractoriness of the AV node and at what level within the cardiac conductive system block occurs. The electrophysiological study can effectively rule out infranodal disease by confirming physiological intranodal block using incremental atrial pacing.

Trans-aortic left ventricular thrombo-embolectomy following COVID-19 infection.

Left ventricular thrombosis is a known complication of myocardial infarction. COVID 19 has been shown to produce a procoagulant state resulting in venous and less commonly arterial thrombosis. Here, we describe a patient who presented with a non-ST elevation myocardial infarction (NSTEMI), in the context of a COVID 19 infection. This NSTEMI resulted in the formation of a large pedunculated apical thrombus, which was initially managed conservatively, however ultimately required surgical thromboembolectomy. Access to the left ventricle was gained via the transaortic route in order to avoid ventriculotomy in a patient with a reduced LV systolic function. Post-operative imaging confirmed complete resection of thrombus.

Multiorgan thrombosis as a complication of COVID-19 pneumonia.

A 47-year-old man, positive for SARS-CoV-2, was diagnosed with acute coronary syndrome (ACS) complicated by myocarditis on a background of COVID-19 pneumonia. He was medically treated for ACS; however, 3 days into his admission, the patient developed neurological complications confirmed on MRI of the brain. MRI showed established infarcts involving a large part of the left temporal lobe and right occipital lobe, with minor foci of micro-haemorrhagic transformation in the left temporal lobe. A left ventricular mural thrombus was then confirmed on echocardiogram, and this was attributed as the cause of his neurological infarct. Further infarctions in the kidneys and spleen, and thrombi in the superior mesenteric and left femoral artery were also identified on imaging of the abdomen. The left ventricular mural thrombus was removed surgically via a midline sternotomy incision under general anaesthesia. Surgery was successful and the patient was discharged to a rehabilitation centre.

Symptomatic digoxin toxicity in a patient on haemodialysis.

We present a man undergoing regular haemodialysis sessions, who presented with non-specific symptoms of nausea, vomiting and light-headedness. He was found to have significantly raised serum digoxin concentrations, as well as a heart rate of 30 beats per minutes. An ECG showed complete heart block. He has a history of non-ischaemic dilated cardiomyopathy with resistant supraventricular and ventricular tachycardias and was on concomitant beta-blockade and digoxin. On questioning, he reported a gradual decline in his residual urine output over the past 6 months. He was reviewed by the cardiology team and required both pharmacological therapy for reversal of digoxin toxicity and temporary pacing in view of significant bradyarrhythmias. The beta-blockade and digoxin were discontinued. He was kept on continuous monitoring at the Cardiac Critical Care Unit. His symptoms resolved spontaneously once digoxin-specific antibody fragments were administered and temporary pacing successfully performed.

HSP72 expression is specific to skeletal muscle contraction type.

Exercise is capable of inducing the cellular stress response and increasing skeletal muscle heat shock protein (HSP) content. HSPs function as molecular chaperones and play roles in facilitating protein folding thereby contributing to muscle proteostasis. To determine the relationship between muscle contraction types, muscle damage, and HSP content, one tibialis anterior (TA) muscle from male Sprague-Dawley rats (n = 5/group) was electrically stimulated while actively lengthening (LC), shortening (SC), or remaining to stagnate (IC) for 15 repetitions (3 sets of five). Two additional LC groups underwent 5 and 10 repetitions. Maximal tetanic tension (MTT) was recorded prior to (pre) and at 5 min after (post) the last contraction. Twenty-four hours after stimulation, TA muscles were removed, processed, and assessed for damage and for HSP25 and HSP72 content. Post-MTT was significantly decreased following 15 LCs, (24%; p < 0.05) but not following 15 SCs or 15 ICs. Post-MTT was also decreased by 8% (p < 0.05), and 18% (p < 0.05) for muscles subjected to 5 and 10 LCs, respectively. HSP72 content increased after all LCs conditions but not following ICs or SCs. HSP25 content remained unchanged following all contractions. Similarly, muscle damage was observed only after LCs and not after other contraction types. In conclusion, muscle HSP72 content can be increased with as few as 5 maximal lengthening contractions and appears to be related to muscle damage. This may have important implications for muscle rehabilitation and exercise training programs.

Segmental colitis associated with diverticulosis: is it the coexistence of colonic diverticulosis and inflammatory bowel disease?

Segmental colitis associated with diverticulosis (SCAD) is an inflammatory process that affects colonic luminal mucosa in segments that are also affected by diverticulosis. Its prevalence varies between 1.15% and 11.4% amongst those suffering from diverticular disease (DD). Being closely associated with DD, it is slightly commoner in males and usually presents in the sixth decade of life. Although the exact pathogenesis of SCAD is unknown, it is probably heterogeneous and includes mechanisms that also play a part in inflammatory bowel disease (IBD). The clinical presentation is non-specific and similar to that of other pathologies involving the sigmoid colon, and its diagnosis is based on endoscopic findings in correlation with histology. Currently, there are no guidelines for its management, which is usually based on the administration of salicylates and antibiotics, with surgery being reserved for refractory cases. The rarity of SCAD may be multifactorial: whereas milder forms go undiagnosed or are attributed to DD, more severe forms can be misdiagnosed as IBD. This latter distinction is an important one to make, since SCAD and IBD differ as regards their natural history and prognosis, while very often no long-term medications are required in SCAD.