Prevalence Martin-Gruberovy anastomózy – elektrofyziologie studie

Objective: Martin-Gruber anastomosis (MGA) is a median-to-ulnar nerve communication in the forearm; three types of MGA occur. Typically, motor fi bres course through the median nerve in the upper arm and elbow, however, they supply the ulnar-innervated muscles of the hand: abductor digiti minimi (ADM) – MGA-I; fi rst dorsal interosseous (FDI) – MGA-II; or adductor pollicis – MGA-III. The objective was to determine the prevalence of MGA in a study group of healthy volunteers. Methods: Two hundred and ninety-two healthy participants (457 arms) were enrolled. Motor and sensory nerve conduction studies of the ulnar and median nerves were performed. Ulnar and median nerve compound muscle action potential amplitudes were obtained on stimulation at the elbow and wrist. Results: We found 109 cases of MGA in 90 arms (MGA-I in 30 arms; MGA-II in 57 arms; MGA-III in 22 arms). We found isolated MGA types in 73 arms, a combination of two types in 15 arms, and occasionally (2 arms) a simultaneous combination of all three types. Conclusion: The prevalence of MGA was 19.7%. Most frequently, we found MGA-II (prevalence = 12.5%). Signifi cance: MGA does not produce any clinical signs. However, it can change EMG results. The neurophysiologist must be able to logically interpret such fi ndings.Úvod: Prevalence Martin-Gruberovy anastomózy (MGA), spojky n. medianus a ulnaris na předloktí se uvádí v rozmezí 15– 39 %. Existují tři různé typy MGA, kdy motorická vlákna jsou v oblasti paže a lokte vedena skrze n. medianus a zásobují svaly ruky inervované n. ulnaris (m. abductor digiti minimi, m. interosseus dorsalis primus či m. adductor pollicis). Soubor a metodika: V pěti EMG laboratořích bylo unifi kovanou technikou vyšetřeno 292 zdravých osob ve věku 20– 67 let, průměr 39,4 let: 166 žen (256 rukou) a 126 mužů (201 rukou), celkem 457 rukou. Byla provedena motorická a senzitivní neurografie n. ulnaris a n. medianus. Pro detekci MGA mělo zásadní význam hodnocení amplitudy CMAP pro n. ulnaris a n. medianus při stimulaci z oblasti lokte a zápěstí. Výsledky: V našem souboru 457 vyšetřených rukou jsme na 90 rukou našli 109 výskytů MGA. U 30 rukou se jednalo o MGA-I, u 57 rukou o MGA-II a u 22 rukou o MGA-III. Izolované typy MGA se vyskytly v 73 případech, Na 17 rukou se vyskytla kombinace dvou, ojediněle dokonce všech tří typů MGA současně. Závěr: V souboru 292 osob zdravých osob jsme na 457 hodnocených rukou našli MGA v 19,7 %. Nejčastěji se vyskytoval typ MGA-II (12,5 %)

Determinants of urban public transport efficiency: case study of the Czech Republic

Abstract Purpose The aim of this paper is to identify the factors influencing efficiency of urban public transport (UPT) systems and to benchmark Czech UPT systems according to their efficiency. Methods The analysis was carried out on a sample of 19 UPT systems in the Czech Republic during 2010–2015. Efficiency was evaluated through a two-stage analysis. Data envelopment analysis (DEA) was used in the first stage. It was based on three inputs (employees, rolling stock and energy) and one output (passengers). DEA efficiency scores were computed for all 19 systems for each year and under two different assumptions regarding returns to scale. In the second stage of the analysis, DEA scores were used in Tobit regression with a set of operational, socio-economic, and demographic explanatory variables in order to find determinants of efficiency. Results Several variables were identified as factors increasing efficiency - proportion of drivers, average vehicle age, the presence of tramlines in the city, total vehicle kilometres, and population density. Some variables were identified as decreasing efficiency – ticket price, proportion of subsidies in revenues, and presence of a two-city system. Czech cities with most efficient transport systems were Prague, Brno, Mariánské Lázně, Olomouc, and Pilsen. The least efficient cities were Chomutov–Jirkov, Ostrava, and Děčín. Conclusions The principal lesson from this study is that bigger cities with greater population densities are more efficient than smaller cities, and the key efficiency factors that local authorities have under their control are the ticket price, rate of subsidies, and structure of the city transport system. The paper contributes to current debate about the efficiency of the urban transport systems and their determinants. There was not much difference between the constant and variable returns to scale results. The results from the second stage could help policy makers make the public transport systems more efficient. Future research could be devoted to gaining data on additional operators which would also enable using additional inputs and outputs for DEA analysis