Search

Obesity, defined as a body mass index (BMI) ≥ 30, is an ever-growing epidemic, with > 35% of adults in the United States currently classified as obese. Super-obese individuals, defined as those who have a BMI ≥ 50, are the fastest-growing portion of this group. This study sought to quantify the infection risk as well as the incidence of surgical, medical, and thromboembolic complications among super-obese patients undergoing total knee arthroplasty (TKA). An all-payer claims database was used to identify patients who underwent elective, primary TKA between 2016 and 2021. Patients who had a BMI ≥ 50 were compared to those who had a normal BMI of 18 to 25. Demographics and the incidence of 90-days postoperative complications were compared between the 2 groups. Univariate analysis and multivariable regression were used to assess differences between groups. In total, 3,376 super-obese TKA patients were identified and compared to 17,659 patients who had a normal BMI. Multivariable analysis indicated that the super-obese cohort was at an increased postoperative risk of periprosthetic joint infection (adjusted odds ratio [aOR] 3.7, 95% confidence interval [CI]: 2.1 to 6.4, P <.001), pulmonary embolism (aOR 2.2, 95%-CI: 1.0 to 5.0, P =.047), acute respiratory failure (aOR 4.1, 95%-CI: 2.7 to 6.1, P <.001), myocardial infarction (aOR 2.5, 95%-CI: 1.1 to 5.8, P =.026), wound dehiscence (aOR 2.3, 95%-CI: 1.4 to 3.8, P =.001), and acute renal failure (aOR 3.2, 95%-CI: 2.4 to 4.2, P <.001) relative to patients who have normal BMI. Super-obese TKA patients are at an elevated risk of postoperative infectious, surgical, medical, and thromboembolic complications. As such, risk stratification, as well as appropriate medical management and optimization, is of utmost importance for this high-risk group. [ABSTRACT FROM AUTHOR]

Previously reported estimates of vertebral artery injuries (VAIs) during cervical spine surgery relied on self-reported survey studies and retrospective cohorts, which may not be reflective of national averages. The largest study to date reports an incidence of 0.07%; however, significant variation exists between different cervical spine procedures. This study aimed to identify the incidence of VAIs in patients undergoing cervical spine procedures for degenerative pathologies. In this retrospective cohort study, a national insurance database was used to access data from the period 2010–2020 of patients who underwent anterior cervical discectomy and fusion, anterior corpectomy, posterior cervical fusion (C3-C7), or C1-C2 posterior fusion for degenerative pathologies. Patients who experienced a VAI were identified, and frequencies for the different procedures were compared. This study included 224,326 patients, and overall incidence of VAIs across all procedures was 0.03%. The highest incidence of VAIs was estimated in C1-C2 posterior fusion (0.12%–1.10%). The number of patients with VAIs after anterior corpectomy, anterior cervical discectomy and fusion, and posterior fusion was 14 (0.06%), 43 (0.02%), and 26 (0.01%), respectively. This is the largest study to date to our knowledge that provides frequencies of VAIs in patients undergoing cervical spine surgery in the United States. The overall incidence of 0.03% is lower than previously reported estimates, but significant variability exists between procedures, which is an important consideration when counseling patients about risks of surgery. [ABSTRACT FROM AUTHOR]

Risk assessment is critically important in elective and high-risk interventions, particularly spine surgery. This narrative review describes the evolution of risk assessment from the earliest instruments focused on general surgical risk stratification, to more accurate and spine-specific risk calculators that quantified risk, to the current era of big data. The PubMed and SCOPUS databases were queried on October 11, 2023 using search terms to identify risk assessment tools (RATs) in spine surgery. A total of 108 manuscripts were included after screening with full-text review using the following inclusion criteria: 1) study population of adult spine surgical patients, 2) studies describing validation and subsequent performance of preoperative RATs, and 3) studies published in English. Early RATs provided stratified patients into broad categories and allowed for improved communication between physicians. Subsequent risk calculators attempted to quantify risk by estimating general outcomes such as mortality, but then evolved to estimate spine-specific surgical complications. The integration of novel concepts such as invasiveness, frailty, genetic biomarkers, and sarcopenia led to the development of more sophisticated predictive models that estimate the risk of spine-specific complications and long-term outcomes. RATs have undergone a transformative shift from generalized risk stratification to quantitative predictive models. The next generation of tools will likely involve integration of radiographic and genetic biomarkers, machine learning, and artificial intelligence to improve the accuracy of these models and better inform patients, surgeons, and payers. [ABSTRACT FROM AUTHOR]

The protein PA1024 from Pseudomonas aeruginosa PAO1 is currently classified as 2-nitropropane dioxygenase, the previous name for nitronate monooxygenase in the GenBankTM and PDB databases, but the enzyme was not kinetically characterized. In this study, PA1024 was purified to high levels, and the enzymatic activity was investigated by spectroscopic and polarographic techniques. Purified PA1024 did not exhibit nitronate monooxygenase activity; however, it displayed NADH:quinone reductase and a small NADH:oxidase activity. The enzyme preferredNADHto NADPH as a reducing substrate. PA1024 could reduce a broad spectrum of quinone substrates via a Ping Pong Bi Bi steady-state kinetic mechanism, generating the corresponding hydroquinones. The reductive half-reaction with NADH showed a kred value of 24 s-1 and an apparent Kd value estimated in the low micromolar range. The enzyme was not able to reduce the azo dye methyl red, routinely used in the kinetic characterization of azoreductases. Finally, we revisited and modified the existing six conserved motifs of PA1024, which define a new class of NADH:quinone reductases and are present in more than 490 hypothetical proteins in the GenBankTM, the vast majority of which are currently misannotated as nitronate monooxygenase. [ABSTRACT FROM AUTHOR]

Abstract: We report structural and 40Ar/39Ar isotopic information on the Eidsfjord shear zone that document it to be a seismogenic, tops-west (hinterland directed), Devonian ductile low angle (25–30° dip, shallowing locally) normal detachment fault. Anorthosite/migmatitic gneiss in the detachment’s upper plate, mangerite in the lower plate, and detachment mylonites are all cut by generations of abundant pseudotachylyte occurring over approximately 150 km2. The mean of four laser 40Ar/39Ar plateau ages for single crystals of recrystallized muscovite from mylonites defining the Eidsfjord shear zone indicates an age of 403.6 ± 1.1 Ma (2σ) for deformation and recrystallization. 40Ar/39Ar step-heating analyses are reported for muscovite from mylonitized rocks of the Fiskefjord shear zone, a nearby tops-east Caledonian thrust that was reactivated as a tops-west normal fault, documenting cooling of the upper plate through the ∼350 °C isotherm at ∼457 Ma. Together with Middle-Ordovician tectonothermal relics found farther west in Lofoten, tops-down-to-the-west normal-slip movement on these extensional shear zones explains maintenance of high-crustal levels throughout the Siluro-Devonian Scandian event. Potassium feldspar 40Ar/39Ar results document a pulse, or multiple pulses, of uplift and cooling between ca. 235 Ma and 185 Ma, consistent with formation of Triassic–Jurassic rift basins flanking the Lofoten Ridge. The Eidsfjord detachment appears to mark the northern terminus of the Early Devonian detachment system traceable 800 km southward to the Nordfjord–Sogn detachment and westward across the North Atlantic to detachments of roughly the same age on the conjugate side of the orogen in East Greenland. The timing, geometry, kinematics, and rheological development of Eidsfjord detachment are grossly similar to the Nordfjord–Sogn detachment but the former contrasts in that it presently lacks exposed deposits of Devonian sedimentary rocks, has smaller magnitudes of displacement, a more prolonged exhumation history, is severely chopped by later high angle normal faults related to rifting and final Eocene continental separation, and it has abundant pseudotachylite occurrences in the upper plate. We interpret the Eidsfjord detachment to be a rare example of an ancient eroded seismogenic low-angle normal fault. [Copyright &y& Elsevier]