Detection of Optical Activity as a Sign of Life

Gas liquid chromatographic techniques for detection of optical activity as sign of lif

False-negative upper extremity ultrasound in the initial evaluation of patients with suspected subclavian vein thrombosis due to thoracic outlet syndrome (Paget-Schroetter syndrome)

OBJECTIVE: To assess the utilization and consequences of upper extremity Duplex ultrasound in the initial diagnostic evaluation of patients with suspected subclavian vein (SCV) thrombosis and venous thoracic outlet syndrome (VTOS). METHODS: A retrospective single-center review was conducted for patients that underwent primary surgical treatment for VTOS between 2008 and 2017, in whom an upper extremity ultrasound had been performed as the initial diagnostic test (n = 214). Clinical and treatment characteristics were compared between patients with positive and false-negative ultrasound studies. RESULTS: There were 122 men (57%) and 92 women (43%) that had presented with spontaneous idiopathic arm swelling, including 28 (13%) with proven pulmonary embolism, at a mean age of 30.7 ± 0.8 years (range 14-69). Upper extremity ultrasound had been performed 23.8 ± 12.2 days after the onset of symptoms, with confirmation of axillary-SCV thrombosis in 169 patients (79%) and negative results in 45 (21%). Of the false-negative ultrasound study reports, only 8 (18%) acknowledged limitations in visualizing the central SCV. Definitive diagnostic imaging (DDI) had been obtained by upper extremity venography in 175 (82%), computed tomography angiography in 24 (11%), and magnetic resonance angiography in 15 (7%), with 142 (66%) undergoing catheter-directed axillary-SCV thrombolysis. The mean interval between initial ultrasound and DDI was 48.9 ± 14.2 days with no significant difference between groups, but patients with a positive ultrasound were more likely to have DDI within 48 hours than those with a false-negative ultrasound (44% vs 24%; P = .02). At the time of surgical treatment, the SCV was widely patent following paraclavicular decompression and external venolysis alone in 74 patients (35%). Patch angioplasty was performed for focal SCV stenosis in 76 (36%) and bypass graft reconstruction for long-segment axillary-SCV occlusion in 63 (29%). Patients with false-negative initial ultrasound studies were significantly more likely to require SCV bypass reconstruction than those with a positive ultrasound (44% vs 25%; P = .02). CONCLUSIONS: Duplex ultrasound has significant limitations in the initial evaluation of patients with suspected SCV thrombosis, with false-negative results in 21% of patients with proven VTOS. This is rarely acknowledged in ultrasound reports, but false-negative ultrasound studies have the potential to delay definitive imaging, thrombolysis, and further treatment for VTOS. Initial false-negative ultrasound results are associated with progressive thrombus extension and a more frequent need for SCV bypass reconstruction at the time of surgical treatment

Reoperative brachial plexus neurolysis after previous anatomically complete supraclavicular decompression for neurogenic thoracic outlet syndrome: A 10-year single-center case series

BACKGROUND: Optimal management of recurrent neurogenic thoracic outlet syndrome (NTOS) remains a considerable challenge. OBJECTIVE: To assess the safety and effectiveness of reoperative brachial plexus neurolysis in patients with recurrent NTOS. METHODS: From 2009 to 2019, 85 patients underwent reoperative supraclavicular brachial plexus neurolysis for recurrent NTOS after a previous anatomically complete supraclavicular decompression. Data from a prospectively maintained database were analyzed retrospectively. RESULTS: The mean patient age at reoperation was 36.9 ± 1.3 (range 15-64) years, 75% were female, and the interval after previous primary operation was 2.5 ± 0.2 years. Intervening injury had precipitated recurrent NTOS in 14 patients (16%), and the mean Disability of the Arm, Shoulder, and Hand (QuickDASH) score before reoperation was 65.2 ± 2.6, reflecting substantial disability. Operative findings consisted of dense fibrous scar tissue surrounding/encasing the brachial plexus. Compared with the previous primary operations, reoperations had a shorter operative time (198 ± 4 vs 161 ± 5 minutes, P \u3c .01) and hospital stay (4.4 ± 0.2 vs 3.6 ± 0.1 days, P \u3c .01), but there were no significant differences in the frequency of prolonged hospitalization (7.1% vs 4.7%), early reoperation (3.5% vs 1.2%), or 30-day hospital readmission (8.2% vs 7.1%). During a median follow-up of 4.8 years, QuickDASH scores improved by 23.3 ± 2.6 (34.2% ± 3.6%; P \u3c .01) and patient-rated outcomes were excellent in 24%, good in 42%, fair in 26%, and poor in 8%. CONCLUSION: Reoperative supraclavicular brachial plexus neurolysis is technically challenging but safe and effective treatment for recurrent NTOS, with significant improvements in symptoms and function. Diminishing perineural scar tissue development and avoiding secondary injury would likely decrease the need for reoperations

Venographic classification and long-term surgical treatment outcomes for axillary-subclavian vein thrombosis due to venous thoracic outlet syndrome (Paget-Schroetter syndrome)

OBJECTIVE: We assessed the clinical presentation, operative findings, and surgical treatment outcomes for axillary-subclavian vein (AxSCV) thrombosis due to venous thoracic outlet syndrome (VTOS). METHODS: We performed a retrospective, single-center review of 266 patients who had undergone primary surgical treatment of VTOS between 2016 and 2022. The clinical outcomes were compared between the patients in four treatment groups determined by intraoperative venography. RESULTS: Of the 266 patients, 132 were male and 134 were female. All patients had a history of spontaneous arm swelling and idiopathic AxSCV thrombosis, including 25 (9%) with proven pulmonary embolism, at a mean age of 32.1 ± 0.8 years (range, 12-66 years). The timing of clinical presentation was acute (\u3c15 days) for 132 patients (50%), subacute (15-90 days) for 71 (27%), and chronic (\u3e90 days) for 63 patients (24%). Venography with catheter-directed thrombolysis or thrombectomy (CDT) and/or balloon angioplasty had been performed in 188 patients (71%). The median interval between symptom onset and surgery was 78 days. After paraclavicular thoracic outlet decompression and external venolysis, intraoperative venography showed a widely patent AxSCV in 150 patients (56%). However, 26 (10%) had a long chronic AxSCV occlusion with axillary vein inflow insufficient for bypass reconstruction. Patch angioplasty was performed for focal AxSCV stenosis in 55 patients (21%) and bypass graft reconstruction for segmental AxSCV occlusion in 35 (13%). The patients who underwent external venolysis alone (patent or occluded AxSCV; n = 176) had a shorter mean operative time, shorter postoperative length of stay and fewer reoperations and late reinterventions compared with those who underwent AxSCV reconstruction (patch or bypass; n = 90), with no differences in the incidence of overall complications or 30-day readmissions. At a median clinical follow-up of 38.7 months, 246 patients (93%) had no arm swelling, and only 17 (6%) were receiving anticoagulation treatment; 95% of those with a patent AxSCV at the end of surgery were free of arm swelling vs 69% of those with a long chronic AxSCV occlusion (P \u3c .001). The patients who had undergone CDT at the initial diagnosis were 32% less likely to need AxSCV reconstruction at surgery (30% vs 44%; P = .034) and 60% less likely to have arm swelling at follow-up (5% vs 13%; P \u3c .05) vs those who had not undergone CDT. CONCLUSIONS: Paraclavicular decompression, external venolysis, and selective AxSCV reconstruction determined by intraoperative venography findings can provide successful and durable treatment for \u3e90% of all patients with VTOS. Further work is needed to achieve earlier recognition of AxSCV thrombosis, prompt usage of CDT, and even more effective surgical treatment

Going places

Journeys. We all make them. Often they take us to exotic places. Sometimes they take us even further. They might take us through time. Or they might take us into a new way of life. There are times too, when we go all over the world and back again only to find that home is, after all, where it’s all happening. This book contains stories about many different types of journey. We hope you will enjoy travelling into it and finding a world that suits you

Eco-evolutionary dynamics, density-dependent dispersal and collective behaviour:implications for salmon metapopulation robustness

The spatial dispersal of individuals plays an important role in the dynamics of populations, and is central to metapopulation theory. Dispersal provides connections within metapopulations, promoting demographic and evolutionary rescue, but may also introduce maladapted individuals, potentially lowering the fitness of recipient populations through introgression of heritable traits. To explore this dual nature of dispersal, we modify a well-established eco-evolutionary model of two locally adapted populations and their associated mean trait values, to examine recruiting salmon populations that are connected by density-dependent dispersal, consistent with collective migratory behaviour that promotes navigation. When the strength of collective behaviour is weak such that straying is effectively constant, we show that a low level of straying is associated with the highest gains in metapopulation robustness and that high straying serves to erode robustness. Moreover, we find that as the strength of collective behaviour increases, metapopulation robustness is enhanced, but this relationship depends on the rate at which individuals stray. Specifically, strong collective behaviour increases the presence of hidden low-density basins of attraction, which may serve to trap disturbed populations, and this is exacerbated by increased habitat heterogeneity. Taken as a whole, our findings suggest that density-dependent straying and collective migratory behaviour may help metapopulations, such as in salmon, thrive in dynamic landscapes. Given the pervasive eco-evolutionary impacts of dispersal on metapopulations, these findings have important ramifications for the conservation of salmon metapopulations facing both natural and anthropogenic contemporary disturbances.This article is part of the theme issue 'Collective movement ecology'