The 'armed concrete' approach: stent-screw-assisted internal fixation (SAIF) reconstructs and internally fixates the most severe osteoporotic vertebral fractures

BackgroundThe treatment of severe osteoporotic vertebral compression fractures (VCFs) with middle-column (MC) involvement, high fragmentation, large cleft and/or pedicular fracture is challenging. Minimally invasive 'stent-screw-assisted internal fixation' (SAIF) can reduce the fracture, reconstruct the vertebral body (VB) and fix it to the posterior elements.ObjectiveTo assess feasibility, safety, technical and clinical outcome of the SAIF technique in patients with severe osteoporotic VCFs.Methods80 treated vertebrae were analyzed retrospectively. Severe VCFs were characterized by advanced collapse (Genant grade 3), a high degree of osseous fragmentation (McCormack grade 2 and 3), burst morphology with MC injury, pediculo-somatic junction fracture, and/or large osteonecrotic cleft. VB reconstruction was evaluated on postprocedure radiographs and CT scans by two independent raters. Clinical and radiological follow-ups were performed at 1 and 6 months.ResultsSAIF was performed at 28 thoracic and 52 lumbar levels in 73 patients. One transient neurological complication occurred. VB reconstruction was satisfactory in 98.8% of levels (inter-rater reliability 96%, κ=1). Follow-up at 1 month was available for 78/80 levels and at 6 months or later (range 6–24, mean 7.9 months) for 73/80 levels. Significant improvement in the Visual Analog Scale score was noted at 1 and 6 months after treatment (p<0.05). Patients reported global clinical benefit during follow-up (Patient’s Global Impression of Change Scale 5.6±0.9 at 1 month and 6.1±0.9 at 6 months). Fourteen new painful VCFs occurred at different levels in 11 patients during follow-up, treated with vertebral augmentation or SAIF. Target-level stability was maintained in all cases.ConclusionsSAIF is a minimally invasive, safe, and effective treatment for patients with severe osteoporotic VCFs with MC involvement.

Analysis of the Intrinsic Predictors of Oronasal Fistula in Primary Cleft Palate Repair Using Intravelar Veloplasty

Introduction: The purpose of the present study was to investigate various factors of cleft palate and to analyze their effect on fistula occurrence following palatal muscle repair using intravelar veloplasty. Methods: A retrospective review of patients who underwent palatoplasty was performed. Primary palatoplasty was performed by a single surgeon in a single center. A total of 165 patients who underwent palatoplasty were enrolled. Primary palatoplasty with levator veli palatini muscle repair using intravelar veloplasty was performed. Three extrinsic factors (age, gender, and body weight) and 6 intrinsic factors (cleft width, ratio of cleft width to intermaxillary tuberosity distance, cleft anterior margin shape, uvula position, cleft lip, and radical intravelar veloplasty) were analyzed. Results: Palatal fistula occurred in 11 (6.67%) patients. The occurrence of fistula was significantly correlated with a specific Veau classification, that is, type II ( P = .041). Fistula tended to occur more frequently with a wide cleft palate ( P = .063), and the high-risk cutoff value of the width was 7.75 mm. Conclusions: A larger cleft width tended to increase the occurrence of fistula. Close observation and information about the higher risk of fistula formation should be given to patients with a large cleft width who underwent intravelar veloplasty.

Evaluation of the Superior Labial Musculomucosal Flap in Dogs: An Angiographic Study and Case Report

Objective The aim of this study was to evaluate the angiosome of the superior and inferior labial arteries within the superior and inferior labia and to describe superior and inferior labial musculomucosal axial pattern flaps that can be used for intra-oral wound reconstruction. This study also presents the clinical use of a superior labial musculomucosal flap in a dog. Materials and Methods The common carotid arteries of six canine cadavers were injected with barium sulphate. The skin of the face and labial mucosa was removed and radiographed to study the vascular supply of the superior and inferior labia. Results The angiograms in all dogs demonstrated that the superior and inferior labial arteries were located within the musculomucosal layer of the labia. At the junction of the rostral and caudal half of the upper lip, extensive choke anastomoses joined the angiosome of the infra-orbital artery. The inferior labial artery perfused the caudal half of the lower labium and had extensive choke anastomoses with the middle and rostral mental arteries. Clinical Significance The musculomucosal flaps of the superior and inferior labia contain a rich arterial blood supply, which suggests that these flaps may survive in live dogs. The superior labial musculomucosal flap was successfully used to reconstruct a large cleft palate in a single clinical case.

Decameric SelA•tRNASec Ring Structure Reveals Mechanism of Bacterial Selenocysteine Formation

The 21st amino acid, selenocysteine (Sec), is synthesized on its cognate transfer RNA (tRNASec). In bacteria, SelA synthesizes Sec from Ser-tRNASec, whereas in archaea and eukaryotes SepSecS forms Sec from phosphoserine (Sep) acylated to tRNASec. We determined the crystal structures of Aquifex aeolicus SelA complexes, which revealed a ring-shaped homodecamer that binds 10 tRNASec molecules, each interacting with four SelA subunits. The SelA N-terminal domain binds the tRNASec-specific D-arm structure, thereby discriminating Ser-tRNASec from Ser-tRNASer. A large cleft is created between two subunits and accommodates the 3′-terminal region of Ser-tRNASec. The SelA structures together with in vivo and in vitro enzyme assays show decamerization to be essential for SelA function. SelA catalyzes pyridoxal 5′-phosphate–dependent Sec formation involving Arg residues nonhomologous to those in SepSecS. Different protein architecture and substrate coordination of the bacterial enzyme provide structural evidence for independent evolution of the two Sec synthesis systems present in nature.

Crystal Structure of Complete Rhinovirus RNA Polymerase Suggests Front Loading of Protein Primer

ABSTRACT Picornaviruses utilize virally encoded RNA polymerase and a uridylylated protein primer to ensure replication of the entire viral genome. The molecular details of this mechanism are not well understood due to the lack of structural information. We report the crystal structure of human rhinovirus 16 3D RNA-dependent RNA polymerase (HRV16 3Dpol) at a 2.4-Å resolution, representing the first complete polymerase structure from the Picornaviridae family. HRV16 3Dpol shares the canonical features of other known polymerase structures and contains an N-terminal region that tethers the fingers and thumb subdomains, forming a completely encircled active site cavity which is accessible through a small tunnel on the backside of the molecule. The small thumb subdomain contributes to the formation of a large cleft on the front face of the polymerase which also leads to the active site. The cleft appears large enough to accommodate a template:primer duplex during RNA elongation or a protein primer during the uridylylation stage of replication initiation. Based on the structural features of HRV16 3Dpo1 and the catalytic mechanism known for all polymerases, a front-loading model for uridylylation is proposed.

Analysis of the Suprabullar and Retrobullar Recesses for Endoscopic Sinus Surgery

Presently, the basic structures and spaces of the paranasal sinuses are more clearly understood by otolaryngologists than ever before. Yet, the more subtle and complex ethmoid features, especially of the ethmoidal pre-recesses and recesses, still elude many otolaryngologists. One of the most nebulous, elusive, and difficult-to-understand recesses is the sinus lateralis, or as it is more correctly called, the retrobullar and suprabullar recesses. The primary purpose of this investigation was to ascertain the prevalence of the sinus lateralis in humans. The secondary purpose was to better characterize this subtle feature of ethmoid anatomy. Human cadaver sinonasal complexes were meticulously dissected by both gross and endoscopic techniques. The hiatus semilunaris superior and sinus lateralis were present in all specimens. A separate and discrete retrobullar recess was present in 93.8%. Typically, a crestlike projection from the basal lamella to the lamina papyracea was noted within the posterior aspect of the retrobullar recess. A single, discrete, well-developed suprabullar recess was present in 70.9%, and a rudimentary suprabullar recess was present in 22.9%. In 7.2%, a single large cleft collectively excavated the retrobullar and suprabullar recess areas; separate retrobullar and suprabullar tracts were not present in this subgroup. Typically, the suprabullar recess was separate from and did not communicate with the frontal recess. The data from this investigation indicate that the separate terms retrobullar recess and suprabullar recess more accurately designate the anatomy and are recommended over the term sinus lateralis.

Structure of Wild Type Yeast RNA Polymerase II and Location of RPB4 and RPB7

Nucleic acid polymerase structure has been studied by both X-ray and electron crystallography. To date, only the smaller, single subunit polymerases have been subjected to X-ray analysis, including the bacteriophage T7 RNA polymerase, which is the only RNA polymerase whose structure is known to atomic resolution. Lower resolution structures of several multisubunit polymerases have been determined by electron crystallography, including a mutant form of yeast RNA polymerase II which lacks subunits Rpb4 and Rpb7 (denoted A4/7 polymerase). All polymerase structures obtained by both X-ray and electron crystallography show a large cleft appropriate in size for binding duplex DNA, and further appear to contain a mobile arm allowing open and closed conformations of the cleft, presumably permitting entry and retention of DNA. Subunits Rpb4 and Rpb7 of RNA polymerase II form a dissociable subcomplex that has been implicated in the stress response and in the initiation of transcription. Human homologs of Rpb4 and Rpb7 have been identified.