Comparative study of episiotomy angles achieved by cutting with straight Mayo scissors and the EPISCISSORS-60 in a birth simulation model.

INTRODUCTION AND HYPOTHESIS: We compared the clinician's ability to cut episiotomies at the recommended 60° angle with traditional straight Mayo scissors compared with patented fixed-angle episiotomy scissors EPISCISSORS-60® in a simulated setting using mounted incision pads. The hypothesis was that fixed-angle episiotomies would achieve a more accurate cutting angle of 60°. METHODS: Angles were cut on episiotomy incision pads in a mounted birth model simulating crowning: 110 midwives and doctors cut an 60° episiotomy with Mayo scissors and then EPISCISSORS-60. Angles were measured with protractors. Average angles were calculated and the one-tailed paired t test was used to compare groups. RESULTS: Mean angle was 45° with Mayo scissors [SD = 9, 95% confidence interval (CI) = 43.3-46.7, interquartile range (IQR) 38-50] and 60° with the EPISCISSORS-60 (SD = 3, 95% CI = 59.3-60.7, IQR = 58-60). Two-thirds of cuts with Mayo scissors were below 50°. CONCLUSIONS: In a simulated setting the majority of operators are unable to cut an episiotomy at the recommended 60° angle with Mayo scissors. The EPISCISSORS-60 cut an episiotomy a statistically significant 15° wider than regular Mayo scissors and achieved the recommended 60° in the vast majority of cases. If these findings translate into real life situations, then cutting episiotomies at 60° is expected to make a valuable contribution in reducing third- and fourth-degree tears in both spontaneous and operative vaginal deliveries. Variability in mediolateral episiotomies should be reduced by use of fixed-angle scissors or through validated health professional training programmes to improve visual accuracy.

Light-induced rearrangement of thioether-substituted phosphanide ligands: scope and limitations of a remarkable isomerization.

Treatment of the thioether-substituted secondary phosphanes R(2)PH(C6H4-2-SR(1)) [R(2) = (Me3Si)2CH, R(1) = Me (1PH), iPr (2PH), Ph (3PH); R(2) = tBu, R(1) = Me (4PH); R(2) = Ph, R(1) = Me (5PH)] with nBuLi yields the corresponding lithium phosphanides, which were isolated as their THF (1-5Pa) and tmeda (1-5Pb) adducts. Solid-state structures were obtained for the adducts [R(2)P(C6H4-2-SR(1))]Li(L)n [R(2) = (Me3Si)2CH, R(1) = nPr, (L)n = tmeda (2Pb); R(2) = (Me3Si)2CH, R(1) = Ph, (L)n = tmeda (3Pb); R(2) = Ph, R(1) = Me, (L)n = (THF)1.33 (5Pa); R(2) = Ph, R(1) = Me, (L)n = ([12]crown-4)2 (5Pc)]. Treatment of 1PH with either PhCH2Na or PhCH2K yields the heavier alkali metal complexes [{(Me3Si)2CH}P(C6H4-2-SMe)]M(THF)n [M = Na (1Pd), K (1Pe)]. With the exception of 2Pa and 2Pb, photolysis of these complexes with white light proceeds rapidly to give the thiolate species [R(2)P(R(1))(C6H4-2-S)]M(L)n [M = Li, L = THF (1Sa, 3Sa-5Sa); M = Li, L = tmeda (1Sb, 3Sb-5Sb); M = Na, L = THF (1Sd); M = K, L = THF (1Se)] as the sole products. The compounds 3Sa and 4Sa may be desolvated to give the cyclic oligomers [[{(Me3Si)2CH}P(Ph)(C6H4-2-S)]Li]6 ((3S)6) and [[tBuP(Me)(C6H4-2-S)]Li]8 ((4S)8), respectively. A mechanistic study reveals that the phosphanide-thiolate rearrangement proceeds by intramolecular nucleophilic attack of the phosphanide center at the carbon atom of the substituent at sulfur. For 2Pa/2Pb, competing intramolecular ß-deprotonation of the n-propyl substituent results in the elimination of propene and the formation of the phosphanide-thiolate dianion [{(Me3Si)2CH}P(C6H4-2-S)](2-).