“…Since then there have been several further reports on this anomaly [Frantz and Aitken, 1967;Monici and Nicolo, 1967;Redhead et al, 1968;Rosenthal, 1968;Pearlman and Bors, 1969;Reeve and Mortimer, 1971;Gadda, 1971;Mongeau and Leclaire, 1972;Nicol, 1972;Marsh and Tejano, 1973;Ignelzi and Lehman, 1974;Nadkarni, 1974;Abraham, 1976;Bhutani and Tayal, 1978;Dal Monte et al 1979;Azouz and Slomic, 1979;Sierra Pérez et al, 1981;Hotston and Carty, 1982;Phillips et al, 1982;Tihansky and Hafeez, 1984;Miller et al, 1985;Fullana et al 1986;Lage et al, 1987;Altamura et al, 1988;Carstens and Schneider, 1989;Pappas et al, 1989;Towfighi and Housman, 1991;Rodríguez et al, 1991;Winter, 1991;Meizner et al, 1992;Dumont et al, 1993;Twickler et al, 1993; Nievelstein et al, 1994;Adra et al, 1994;Horrow et al, 1995;Subtil et al, 1998]. A classification was proposed on the basis of gradations of severity.…”