Graphical Abstract Highlights d Severe COVID-19 patients display immune dysregulation or macrophage activation syndrome d Severe respiratory failure is associated with a major decrease of HLA-DR on CD14 monocytes d CD4 cell and NK cell cytopenias are characteristics of severe COVID-19 d IL-6 blocker Tocilizumab partially rescues SARS-CoV-2associated immune dysregulation

Introduction With the advances and improvement of computer-assisted surgery devices, computer-guided pedicle screws insertion has been applied to the lumbar, thoracic and cervical spine. The purpose of the present study was to perform a systematic review of all available prospective evidence regarding pedicle screw insertion techniques in the thoracic and lumbar human spine. Materials and methodsWe considered all prospective in vivo clinical studies in the English literature that assessed the results of different pedicle screw placement techniques (free-hand technique, fluoroscopy guided, computed tomography (CT)-based navigation, fluoro-based navigation). MEDLINE, OVID, and Springer databases were used for the literature search covering the period from January 1950 until May 2010. Results 26 prospective clinical studies were eventually included in the analysis. These studies included in total 1,105 patients in which 6,617 screws were inserted. In the studies using free-hand technique, the percentage of the screws fully contained in the pedicle ranged from 69 to 94%, with the aid of fluoroscopy from 28 to 85%, using CT navigation from 89 to 100% and using fluoroscopy-based navigation from 81 to 92%. The screws positioned with free-hand technique tended to perforate the cortex medially, whereas the screws placed with CT navigation guidance seemed to perforate more often laterally. ConclusionsIn conclusion, navigation does indeed exhibit higher accuracy and increased safety in pedicle screw placement than free-hand technique and use of fluoroscopy.

BCG vaccination in children protects against heterologous infections and improves survival independently of tuberculosis prevention. The phase III ACTIVATE trial assessed whether BCG has similar effects in the elderly. In this double-blind, randomized trial, elderly patients (n = 198) received BCG or placebo vaccine at hospital discharge and were followed for 12 months for new infections. At interim analysis, BCG vaccination significantly increased the time to first infection (median 16 weeks compared to 11 weeks after placebo). The incidence of new infections was 42.3% (95% CIs 31.9%–53.4%) after placebo vaccination and 25.0% (95% CIs 16.4%–36.1%) after BCG vaccination; most of the protection was against respiratory tract infections of probable viral origin (hazard ratio 0.21, p = 0.013). No difference in the frequency of adverse effects was found. Data show that BCG vaccination is safe and can protect the elderly against infections. Larger studies are needed to assess protection against respiratory infections, including COVID-19 (ClinicalTrials.gov NCT03296423).

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A rare case of unilateral bicondylar fractures of the femoral condyles is presented. Internal fixation of the fragments was achieved by three cancellous lag screws, followed by a short period of cast immobilization and intensive physiotherapy. Full weight bearing was allowed 3 months postoperatively. Full range of motion of the knee and no presence of articular defects on femoral condyles were observed 2 years after hardware and heterotopic ossification removal.

Incomplete reproductive isolation between related species of birds at contact zones is increasingly being documented. Such hybridization typically occurs between sister taxa that diverged in relatively recent times, and hybrids are most often identified based on their intermediate phenotypic characteristics and, increasingly, through genetic admixture analysis. When species have been diverging over relatively longer time scales, prezygotic isolation barriers are expected to evolve, precluding maladaptive interbreeding. Here, we examine the extent of introgressive hybridization in a pair of African barbets, the yellow-fronted tinkerbird (Pogoniulus chrysoconus extoni) and the red-fronted tinkerbird (Pogoniulus pusillus pusillus), which were not previously known to interbreed, across a contact zone in Southern Africa. Although there were significant differences in the coloration of plumage between the species, we found a pattern of extensive admixture in and around the contact zone. Nonetheless, the two species appear to have diverged > 4 Mya and might not even be sister taxa, suggesting that time of divergence alone might not be sufficient for the evolution of prezygotic reproductive barriers. Significantly more phenotypically red-fronted individuals had a P. c. extoni (yellow-fronted) genetic background than vice versa, suggesting possible asymmetry in mate preferences. Sexual selection may thus play a role in breaking down species barriers despite the extent of genetic divergence.

Background:The term “SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis) syndrome” includes a variety of musculoskeletal disorders associated with skin conditions; Osteitis is the most prominent skeletal lesion, whereas palmoplantar pustulosis and acne are the main skin lesions. Diagnosing SAPHO syndrome is difficult, because this syndrome is often confused with suppurative osteomyelitis, which has similar clinical and pathologic findings. SAPHO diagnosis is even more difficult when atypical sites are involved and there are no skin lesions.Patients and Methods:This case series presents five patients (3 women, 2 men), ages 27 to 44 years, who came to the Orthopaedic Department outpatient clinic for evaluation of pain in the humerus, clavicle, sacroiliac joints, and/or distal radius, and were diagnosed with SAPHO syndrome. Clinical and radiologic findings, treatment and outcome data, with up to 4 years of follow-up are presented. An extensive discussion of the clinical presentation, published literature, treatment options and outcome of SAPHO syndrome is also included.Results:Once the diagnosis of SAPHO syndrome was established, treatment with antibiotics (clindamycin) and non steroid anti-inflammatory drugs (lornoxicam) was remarkably effective. All patients did well and remained symptom free for up to four years, after a 3-8 month course of treatment.Interpretation:SAPHO syndrome should be included in the differential diagnosis when evaluating patients with lytic, sclerotic, or hyperostotic bone lesions and pain. Prompt SAPHO syndrome recognition, followed by appropriate therapy with antibiotics and NSAIDs can produce rapid symptom resolution, while avoiding unnecessary procedures and longterm antibiotic therapy.

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