Aqueous divalent metal-nitrate interactions: hydration versus ion pairing.

Nitrate aqueous solutions, Mg(NO(3))(2), Ca(NO(3))(2), Sr(NO(3))(2), and Pb(NO(3))(2), are investigated using Raman spectroscopy and free energy profiles from molecular dynamics (MD) simulations. Analysis of the in-plane deformation, symmetric stretch, and asymmetric stretch vibrational modes of the nitrate ions reveal perturbation caused by the metal cations and hydrating water molecules. Results show that Pb(2+) has a strong tendency to form contact ion pairs with nitrate relative to Sr(2+), Ca(2+), and Mg(2+), and contact ion pair formation decreases with decreasing cation size and increasing cation charge density: Pb(2+) \u3e Sr(2+) \u3e Ca(2+) \u3e Mg(2+). In the case of Mg(2+), the Mg(2+)-OH(2) intermolecular modes indicate strong hydration by water molecules and no contact ion pairing with nitrate. Free energy profiles provide evidence for the experimentally observed trend and clarification between solvent-separated, solvent-shared, and contact ion pairs, particularly for Mg(2+) relative to other cations

Pin tract infection of operatively treated supracondylar fractures in children: long-term functional outcomes and anatomical study.

PURPOSE: The purpose of our study was to determine the long-term functional outcomes of pin tract infection after percutaneous pinning of displaced supracondylar humeral fractures in children, and to evaluate the potential for intracapsular pin placement based on pin configuration in cadaveric elbows. METHODS: We conducted a retrospective review of all patients requiring percutaneous pinning in a single institution over a 19-year period. The functional outcome assessment consisted of a telephone interview using the Disabilities of the Arm, Shoulder and Hand (DASH)] Outcome Measure and the Patient-Rated Elbow Evaluation (PREE) questionnaires. The risk of intracapsular pin placement was studied in cadaveric elbows for the three most common pin configurations: divergent lateral, parallel lateral, and medial and lateral crossed pins. RESULTS: Of 490 children, 21 (4.3 %) developed pin tract infection. There were 15 (3.1 %) superficial and six (1.2 %) deep infections (osteomyelitis and septic arthritis). Both DASH and PREE scores were excellent at a mean of 18 years post-surgery. The risk of intracapsular pin placement using parallel lateral pins was found to be greater (p \u3c 0.05) than either crossed or divergent lateral pinning configurations. CONCLUSIONS: Most infections after pinning of supracondylar humerus fractures are superficial and can be managed with pin removal, oral antibiotics, and local wound care. Septic arthritis and osteomyelitis are rare complications; when they do occur, they seem to be associated with parallel lateral pin configuration, though a causal relationship could not be established from the current study. Satisfactory long-term outcomes of these deep infections can be expected when treated aggressively with surgical debridement and intravenous antibiotics

Multidisciplinary team approach in the management of popliteal artery injury.

Popliteal artery injuries (PAIs) remain a challenging entity and carry the greatest risk of limb loss among traumatic lower extremity vascular injuries. Operative management of traumatic popliteal vascular injuries continues to evolve. Improved diagnostic imaging and the introduction of endovascular techniques offered alternative modalities to traditional surgical management. Despite major efforts in establishing protocols and guidelines in the management of vascular trauma, optimal strategies of traumatic PAIs are still under investigation. Herein, we discussed the role of multidisciplinary team, involving trauma and endovascular surgeons, emergency department personnel, and interventional radiologists in the management of complex PAIs

Critical Analysis of Vertebral Artery Flow Patterns/Subclavian Steal Detected by Cerebrovascular Duplex Ultrasound Exams and Its Clinical Implications.

BACKGROUND: The prevalence of subclavian steal (defined as retrograde/bidirectional vertebral artery flow) in the general population and in patients undergoing cerebrovascular duplex ultrasound (CDUS) exams is variable. This is the largest study to date to analyze the incidence of duplex-suggested subclavian steal in 5615 CDUS exams over a one year period and to examine its clinical implications. PATIENT POPULATION AND METHODS: All consecutive CDUS exams performed over a one year period were examined for the presence of subclavian steal. Indications of testing, presence of posterior cerebral circulation/subclavian steal symptoms, and any interventions for subclavian steal were analyzed. RESULTS: 171/5,615 (3.1%) were found to have subclavian steal (duplex-suggested). 117 (2.1%) had retrograde flow and 54 (1%) had bidirectional flow. 104/171 (60.8%) were left sided. Indications for CDUS were: post CEA/CAS surveillance in 39 patients (22.8%), surveillance for progression of carotid stenosis in 76 patients (44.4%), TIA/stroke in 26 patients (15%), asymptomatic screening/carotid bruit in 18 patients (10.5%) and isolated posterior cerebral circulation symptoms in 12 patients (7%). 63% of patients had associated \u3e50% carotid stenosis. The mean arm Doppler pressure gradient was 32.2 mmHg for asymptomatic patients vs 37mmHg for patients with posterior circulation symptoms (p=.3254). There were significant differences between the mean systolic arm pressure for patients with retrograde vs antegrade vs bidirectional flow (105 mmHg vs 146 vs 134, p50% subclavian stenosis or occlusion (100/117 had subtotal/total occlusion) except for one patient. Meanwhile, 52/54 patients with bidirectional flow had \u3e50% subclavian stenosis (6/54 with subtotal/total occlusion) while two patients were normal/ CONCLUSIONS: The incidence of subclavian steal in patients who undergo CDUS is relatively rare. Most of these patients are asymptomatic and can be treated conservatively with only a few percentage who may need intervention for disabling symptoms with good symptom resolution

A single-center experience of 30-day perioperative and one year clinical outcomes of transcarotid artery revascularization in 100 consecutive patients.

BACKGROUND: Transcarotid Artery Revascularization (TCAR) using the ENROUTE system (Silk Road) has been proposed as a safe and effective alternative to both carotid endarterectomy (CEA) and transfemoral carotid artery stenting (TF-CAS). Two large registries (ROADSTER 1 and ROADSTER 2) have shown that TCAR has acceptable/low rates of perioperative stroke/death. This study will analyze the 30-day perioperative and 1-year clinical outcomes from a single-center. PATIENT POPULATION AND METHODS: This is a retrospective analysis of prospectively collected data from SVS/VQI TCAR surveillance project (TSP) of 100 consecutive patients (102 TCAR procedures) done in our institution. These procedures were done for high-risk patients for CEA, which included anatomical (previous CEA, high cervical lesion, neck radiation, stoma, arch type, etc.), physiological (CHF, severe coronary artery disease, COPD on O RESULTS: 100 consecutive high-risk patients for CEA included: 38% anatomical, 44% physiological, and 18% combined anatomical and physiological reasons. The mean age was 72.5 years (range 52-90 years). Indications for TCAR were 34% for symptomatic lesions (TIA/stroke) and 66% for asymptomatic lesions. Mean ipsilateral treated stenosis was 80.4%. Contralateral ≥50% stenosis/occlusion was present in 31% of patients. Technical success rate was 100%. 92% had pre-stenting PTA and 26% had post-stenting PTA. The mean flow reversal time was 8.5 min (range 3-26 min). The 30-day perioperative stroke rate was 2.9% (1/67, 1.5% for asymptomatic patients), the stroke/death rate was 2.9%, and stroke/death and MI rate was 3.9% (4/102). Other perioperative complications included cranial nerve injury 3/102 (2.9%), carotid artery dissection (2%), and major hematoma (necessitated operation evacuation) (5.9%). Freedom from stroke rates and stroke/death rates at 1 year were: 90% and 89%. Freedom from ≥50% and ≥80% in-stent restenosis rates at 1 year were 82% and 90%, respectively. None of these restenosis were symptomatic except two (2/13). Freedom from reintervention rate at 1 year was 98%. CONCLUSION: Although the perioperative events were somewhat higher than what has been reported in previous registries, TCAR for patients who are high-risk for CEA has a low perioperative stroke and stroke/death rates with satisfactory outcome at 1 year. Further long-term data is probably needed to verify long-term outcome