Rare Case of Traction Sural Neuropathy due to Acute Achilles Tendon Rupture

Sural nerve injury (SNI) is a reported complication of acute Achilles tendon rupture (ATR), primarily iatrogenic in operatively managed cases. The sural nerve typically runs along the lateral border of the Achilles tendon. Its branches provide sensory information from the lateral foot and ankle. Given its proximity to the Achilles tendon, sural nerve-related complications in operatively managed cases are a known adverse outcome. However, the incidence of SNI in conservatively managed cases is thought to be much less common. Most patients recover to normal sensation by one year of injury to the sural nerve. CASE DESCRIPTION: A previously healthy 30 y.o. male presented with acute onset right posterior lower leg pain that occurred while running. He was clinically diagnosed with a complete ATR. Additionally, the patient reported numbness and tingling in the right lateral hindfoot since the time of injury. CLINICAL COURSE: The patient opted to pursue conservative management for his ATR with an accelerated functional rehabilitation protocol. However, he continued to endorse minimally improved sensory deficits in the sural nerve distribution nearly one year post-injury. The patient felt these symptoms were negatively impacting his return to full physical function, prompting further testing. Nerve conduction studies were consistent with an isolated right sural sensory neuropathy that was chronic and axonal in nature. Nonsurgical management and conservative treatment were recommended, including a discussion regarding the natural history of nerve healing and the available treatment options for nerve injuries. CONCLUSION: SNI associated with ATR likely results from traction on the nerve at the time of injury. Prior literature has focused on the incidence of sural nerve injury in the setting of operative repair of ATR. This case highlights the rarity of SNI in the absence of surgical repair and the importance of assessing for SNI in all cases of acute ATR

Anomalous Rib and Nonunion of a First Rib Fracture Causing Thoracic Outlet Syndrome in a Football Player

HISTORY: An 18-year-old male right hand dominant football player with past medical history of complete right ACL tear presents with chronic right neck and shoulder pain for two years after a shoulder press exercise. Four months later, he fell from a fence with his right arm outstretched. One year after the initial event, during football training, he sustained a shoulder injury with a pop under his shoulder blade. PHYSICAL EXAM: There is asymmetry of the trapezius muscles with obvious indentation of the right anterior supraclavicular region compared to the left. There is also subluxation of the right ulnar nerve at the elbow, with negative Tinel sign at the cubital tunnel or Guyon canal. DIFFERENTIAL DIAGNOSES: Muscle strain (e.g., levator scapulae or trapezius mm.) Neurogenic thoracic outlet syndrome Arterial thoracic outlet syndrome Venous thoracic outlet syndrome TEST AND RESULTS: X-rays at the current visit reveal bilateral chronic stress fractures of the first ribs with non-union. These x-ray results along with the patient’s symptoms are consistent with a neurogenic thoracic outlet syndrome (nTOS). Follow-up EMG of the right upper extremity muscles was normal. Because of the patient’s neuropathic symptoms and potential nTOS, an MRI was ordered to evaluate for possible right brachial plexus pathology. MRI is significant for pseudoarthroses of the bilateral first ribs with secondary superior kinking of the right T1 and to a lesser degree right C8 nerve roots. FINAL WORKING DIAGNOSIS: Neurogenic thoracic outlet syndrome (nTOS) Secondary to mass effect from anomalous rib and nonunion of a first rib fracture. TREATMENT AND OUTCOMES: This patient’s treatment regimen for neurogenic thoracic outlet syndrome included planning for surgical removal of the right first rib by the plastic surgery and vascular surgery team versus physical therapy. The patient’s recovery would entail rehabilitation through physical therapy and is now ongoing. He has not required surgical intervention

Bilateral Tibial Stress Fracture in an Inexperienced Athlete

PURPOSE: An abrupt increase in duration, intensity, or frequency of physical activity without adequate periods of rest can make patients susceptible to stress fractures, which are typically unilateral and located in the posteromedial tibia diaphysis. METHODS: We present a unique case report of a bilateral proximal epiphysis stress fracture. RESULTS: Here we present a young female patient presenting with bilateral tibia stress fractures after running in a half marathon that she had not trained for. Initial radiographs did not reveal any acute abnormalities, but subsequent MRI demonstrated incomplete stress fractures of the bilateral medial tibial epiphysis. Conservative management including compressive knee sleeves was initiated, with reduced pain reported at the follow-up visit. This patient’s intrinsic risk factors for stress included female gender, while her extrinsic risk factors included poor footwear, improper training, and foot anomalies. Even in the absence of significant intrinsic risk factors, stress fractures should be included on the differential if history reveals recent intense physical exercise. CONCLUSION: History was vital in detecting and treating this patient’s bilateral knee pain. We were fortunate enough to have a clinical suspicion of stress fracture and our patient is progressing towards her baseline

Snapping Triceps Syndrome: A Rare Cause of Medial Elbow Pain

PURPOSE: Snapping medial triceps is a relatively rare cause of medial elbow pain that occurs when the tricep tendon dislocates over the medial or lateral epicondyle. Physical exams usually demonstrate intermittent medial elbow pain with extreme elbow flexion or extension, however dynamic diagnostic studies allow for direct visualization of the dislocating tricep. This case report adds to the sparse literature on snapping medial triceps. METHODS: We report a rare occurrence of snapping medial triceps in a young female who initially presented with pain at the posteromedial right elbow with extreme flexion and extension. Intermittent snapping of the medial elbow was noted on physical exam. Ultrasound confirmed snapping of the medial triceps head over osteophytes of the posteromedial olecranon. The patient agreed to surgical right medial triceps release with excision of elbow osteophytes. RESULTS: As demonstrated with our case, static diagnostic imaging such as radiographs and MRI may not adequately characterize snapping triceps syndrome. It is crucial for providers to be aware of subtle differences between dynamic and static diagnostics imaging for snapping medial tricep syndrome. Another important diagnostic tools are electrodiagnostic studies, however as displayed with our patient there may be absence of any ulnar neuropathy at the level of the elbow, which could hinder providers from concerning snapping medial tricep syndrome. CONCLUSION: It is important to consider a broad differential that includes snapping triceps syndrome in a patient presenting with medial elbow pain. EMG and ultrasonography can be useful in differentiating snapping medial triceps from ulnar nerve instability. Treatment can include activity modification, elbow splinting, or surgical release of the snapping part of the triceps

1,4,5,8-Naphthalene Tetracarboxylate Dianhydride/g-C\u3csub\u3e3\u3c/sub\u3eN\u3csub\u3e4\u3c/sub\u3e van der Waals Heterojunctions Exhibit Enhanced Photochemical H\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e2\u3c/sub\u3e Production and Antimicrobial Activity

Organic semiconductors, including graphitic carbon nitride (g-C3N4, CN), represent an important class of materials for the development of novel antimicrobial or biomedical technologies. Of principal interest is the ability of these materials to catalyze the reduction of elemental oxygen to generate reactive oxygen species (ROS), including hydrogen peroxide (H2O2). Here, we describe the fabrication of photoactive van der Waals heterojunctions incorporating 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA) and CN. The composite heterojunction systems were characterized by a combination of physical (TEM, SEM, pXRD), spectroscopic (FT-IR, XPS, DRUV, photoluminescence, TCSPC) and kinetic experiments. Electronic interactions between the two components of the heterojunction increase the rate of photochemical production of H2O2 from elemental oxygen by 410%, relative to samples of pure CN. Mechanistic analysis reveals that interaction of NTCDA with the surface of CN modifies the mechanism of H2O2 formation in the heterojunction photocatalysts. The photochemical production of H2O2 by irradiation of the most active heterojunction composition is sufficient to reduce the viability of E. coli O157:H7, S. aureus and Ps. aeruginosa PAO1 by 99%. Importantly, H2O2 production by the NTCDA/CN heterojunctions suppresses Ps. aeruginosa biofilm formation, even at light exposure doses that had a lesser impact on overall planktonic cell growth

Effect of Uniaxial Compression Frequency on Osteogenic Cell Responses in Dynamic 3D Cultures

The application of mechanical stimulation on bone tissue engineering constructs aims to mimic the native dynamic nature of bone. Although many attempts have been made to evaluate the effect of applied mechanical stimuli on osteogenic differentiation, the conditions that govern this process have not yet been fully explored. In this study, pre-osteoblastic cells were seeded on PLLA/PCL/PHBV (90/5/5 wt.%) polymeric blend scaffolds. The constructs were subjected every day to cyclic uniaxial compression for 40 min at a displacement of 400 μm, using three frequency values, 0.5, 1, and 1.5 Hz, for up to 21 days, and their osteogenic response was compared to that of static cultures. Finite element simulation was performed to validate the scaffold design and the loading direction, and to assure that cells inside the scaffolds would be subjected to significant levels of strain during stimulation. None of the applied loading conditions negatively affected the cell viability. The alkaline phosphatase activity data indicated significantly higher values at all dynamic conditions compared to the static ones at day 7, with the highest response being observed at 0.5 Hz. Collagen and calcium production were significantly increased compared to static controls. These results indicate that all of the examined frequencies substantially promoted the osteogenic capacity

Comparison of advanced gravitational-wave detectors

We compare two advanced designs for gravitational-wave antennas in terms of their ability to detect two possible gravitational wave sources. Spherical, resonant mass antennas and interferometers incorporating resonant sideband extraction (RSE) were modeled using experimentally measurable parameters. The signal-to-noise ratio of each detector for a binary neutron star system and a rapidly rotating stellar core were calculated. For a range of plausible parameters we found that the advanced LIGO interferometer incorporating RSE gave higher signal-to-noise ratios than a spherical detector resonant at the same frequency for both sources. Spheres were found to be sensitive to these sources at distances beyond our galaxy. Interferometers were sensitive to these sources at far enough distances that several events per year would be expected

First all-sky search for continuous gravitational waves from unknown sources in binary systems

We present the first results of an all-sky search for continuous gravitational waves from unknown spinning neutron stars in binary systems using LIGO and Virgo data. Using a specially developed analysis program, the TwoSpect algorithm, the search was carried out on data from the sixth LIGO science run and the second and third Virgo science runs. The search covers a range of frequencies from 20 Hz to 520 Hz, a range of orbital periods from 2 to ∼2,254  h and a frequency- and period-dependent range of frequency modulation depths from 0.277 to 100 mHz. This corresponds to a range of projected semimajor axes of the orbit from ∼0.6 × 10[superscript −3]  ls to ∼6,500  ls assuming the orbit of the binary is circular. While no plausible candidate gravitational wave events survive the pipeline, upper limits are set on the analyzed data. The most sensitive 95% confidence upper limit obtained on gravitational wave strain is 2.3 × 10[superscript −24] at 217 Hz, assuming the source waves are circularly polarized. Although this search has been optimized for circular binary orbits, the upper limits obtained remain valid for orbital eccentricities as large as 0.9. In addition, upper limits are placed on continuous gravitational wave emission from the low-mass x-ray binary Scorpius X-1 between 20 Hz and 57.25 Hz.National Science Foundation (U.S.)United States. National Aeronautics and Space AdministrationCarnegie TrustDavid & Lucile Packard FoundationResearch CorporationAlfred P. Sloan Foundatio

Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A

On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is 5.0 × 10 -8 . We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of (+1.74±0.05)between GRB 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between -3 × 10 -15 and +7 × 10 -16 times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1-1.4 per year during the 2018-2019 observing run and 0.3-1.7 per year at design sensitivity

Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory

The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV-EeV energy range using the Antares, IceCube, and Pierre Auger Observatories. No neutrinos directionally coincident with the source were detected within ± 500 s around the merger time. Additionally, no MeV neutrino burst signal was detected coincident with the merger. We further carried out an extended search in the direction of the source for high-energy neutrinos within the 14 day period following the merger, but found no evidence of emission. We used these results to probe dissipation mechanisms in relativistic outflows driven by the binary neutron star merger. The non-detection is consistent with model predictions of short GRBs observed at a large off-axis angle