Semitendinosus tendon graft for coracoclavicular ligament reconstruction resulted in significantly superior clinical and radiologic outcomes compared to the modified Weaver-Dunn procedure.

With the delta variant of COVID-19, known as B.1.617.2, quickly ramping up infections around the world, we need to understand what makes this variant more contagious. One study has reported that the delta variant is 60% more transmissible than the alpha variant. As of August 2021, the delta variant has quickly become the dominant strain. Despite countries like the US, where most of the population is vaccinated, COVID-19 has made a resurgence in infections. Collectively, as a country, we ask: is it more deadly? What makes it more “contagious” or “transmissible”? This review article delves into the information we already know about the delta variant and how it compares with the other SARS-CoV-2 variants. The current vaccine companies like AstraZeneca, Pfizer/BioNTech, and Moderna have reported that their vaccines can provide protection against this variant but with a slightly reduced efficacy. In this article, we do a comprehensive review and summary of the delta B.1.617.2 variant and what makes it more contagious.

Multilevel cervical spine procedures can challenge the stability of current anterior cervical screw-and-plate systems, particularly in cases of severe three-column subaxial cervical spine injuries and multilevel plated reconstructions in osteoporotic bone. Supplemental posterior instrumentation is therefore recommended to increase primary construct rigidity and diminish early failure rates. The increasing number of successfully performed posterior cervical pedicle screw fixations have enabled more stable fixations, however most cervical pathologies are located anteriorly and preferably addressed by an anterior approach. To combine the advantages of the anterior approach with the superior biomechanical characteristics of cervical pedicle screw fixation, the authors developed a new concept of a cervical anterior transpedicular screw-and-plate system. An in vivo anatomical study was performed to explore the feasibility of anterior transpedicular screw fixation (ATPS) in the cervical spine. The morphological study was conducted based on 29 cervical spine CT scans from healthy patients and measurements were performed on the pedicle sizes, angulations, vertebral body depth, height and width at C2 to T1. Significant morphologic parameters for the new technique are discussed. These parameters include the sagittal and transverse intersection points of the pedicle axis with the anterior vertebral body wall, as well as the distances between sagittal intersection points from C2 to T1. On the basis of these results, standard spine models were reconstructed and used for the conceptual development of a preclinical release prototype of an anterior transpedicular screw-and-plate system. The morphological feasibility of the new technique is demonstrated, and its indications, biomechanical considerations, as well as surgical prerequisites are thoroughly discussed. In the future, the technique of cervical anterior transpedicular screw fixation might diminish the number of failures in the reconstruction of multilevel and three-column cervical spine instabilities, and avoid the need for supplemental posterior instrumentation.

Reconstruction after multilevel decompression of the cervical spine, especially in the weakened osteoporotic, neoplastic or infectious spine often requires circumferential stabilization and fusion. To avoid the additional posterior surgery in these cases while increasing rigidity of anterior-only screw-plate constructs, the authors introduce the concept of anterior transpedicular screw (ATPS) fixation. We demonstrated its morphological feasibility as well as its indications in a previous study in Part I of our project. Consequently, the objectives of the current study were to assess the ex vivo accuracy of placing ATPS into the cervical vertebra as well as the biomechanical performance of ATPS in comparison to traditional vertebral body screws (VBS) in terms of pull-out strength (POS). Twenty-three ATPS were inserted alternately to two screws into the pedicles and vertebral bodies, respectively, of six cadaveric specimens from C3-T1. For insertion of ATPS, a manual fluoroscopically assisted technique was used. Preand post insertional CT-scans were used to assess accuracy of ATPS insertion in the axial and sagittal planes. A newly designed grading system and accuracy score were used to delineate accuracy of ATPS insertion. Following insertion of screws, 23 ATPS and 22 VBS were subjected to pull-out testing (POT). The bone mineral density (BMD) of each specimen was assessed prior to POT. Statistical analysis showed that the incidence of correctly placed screws and non-critical pedicles breaches in axial plane was 78.3%, and 95.7% in sagittal plane. Hence, according to our definition of ''critical'' pedicle breach that exposes neurovascular structures at risk, 21.7% (n = 5) of all ATPS inserted showed a critical pedicle breach in axial plane. Notably, no critical pedicle perforation occurred at the C6 to T1 levels. Pull-out testing of ATPS and VBS revealed that pull-out ( ) 17:539-555 DOI 10.1007 resistance of ATPS was 2.5-fold that of VBS. Mean POS of 23 ATPS with a mean BMD of 0.566 g/cm 2 and a mean osseus screw purchase of 27.2 mm was 467.8 N. In comparison, POS of 22 VBS screws with a mean BMD of 0.533 g/cm 2 and a mean osseus screw purchase of 16.0 mm was 181.6 N. The difference in ultimate pull-out strength between the ATPS and VBS group was significant (p \ 0.000001). Also, accuracy of ATPS placement in axial plane was shown to be significantly correlated with POS. In contrast, there was no correlation between screw-length, BMD, or level of insertion and the POS of ATPS or VBS. The study demonstrated that the use of ATPS might be a new technique worthy of further investigation. The use of ATPS shows the potential to increase construct rigidity in terms of screw-plate pull-out resistance. It might diminish construct failures during anterior-only reconstructions of the highly unstable decompressed cervical spine.123 Eur Spine J

BackgroundThe clinical efficacy of the Angiotensin II (AngII) receptor AT2R antagonist EMA401, a novel peripherally-restricted analgesic, was reported recently in post-herpetic neuralgia. While previous studies have shown that AT2R is expressed by nociceptors in human DRG (hDRG), and that EMA401 inhibits capsaicin responses in cultured hDRG neurons, the expression and levels of its endogenous ligands AngII and AngIII in clinical neuropathic pain tissues, and their signalling pathways, require investigation. We have immunostained AngII, AT2R and the capsaicin receptor TRPV1 in control post-mortem and avulsion injured hDRG, control and injured human nerves, and in cultured hDRG neurons. AngII, AngIII, and Ang-(1-7) levels were quantified by ELISA. The in vitro effects of AngII, AT2R agonist C21, and Nerve growth factor (NGF) were measured on neurite lengths; AngII, NGF and EMA401 effects on expression of p38 and p42/44 MAPK were measured using quantitative immunofluorescence, and on capsaicin responses using calcium imaging.ResultsAngII immunostaining was observed in approximately 75% of small/medium diameter neurons in control (n = 5) and avulsion injured (n = 8) hDRG, but not large neurons i.e. similar to TRPV1. AngII was co-localised with AT2R and TRPV1 in hDRG and in vitro. AngII staining by image analysis showed no significant difference between control (n = 12) and injured (n = 13) human nerves. AngII levels by ELISA were also similar in control human nerves (4.09 ± 0.36 pmol/g, n = 31), injured nerves (3.99 ± 0.79 pmol/g, n = 7), and painful neuromas (3.43 ± 0.73 pmol/g, n = 12); AngIII and Ang-(1-7) levels were undetectable (<0.03 and 0.05 pmol/g respectively). Neurite lengths were significantly increased in the presence of NGF, AngII and C21 in cultured DRG neurons. AngII and, as expected, NGF significantly increased signal intensity of p38 and p42/44 MAPK, which was reversed by EMA401. AngII mediated sensitization of capsaicin responses was not observed in the presence of MAP kinase inhibitor PD98059, and the kinase inhibitor staurosporine.ConclusionThe major AT2R ligand in human peripheral nerves is AngII, and its levels are maintained in injured nerves. EMA401 may act on paracrine/autocrine mechanisms at peripheral nerve terminals, or intracrine mechanisms, to reduce neuropathic pain signalling in AngII/NGF/TRPV1-convergent pathways.