Chapter 1 continued
4. Anatomical Considerations Of Hypospadias
As already outlined, the term hypospadias refers to the position of the genito-urinary orifice – the urethral meatus – when it opens somewhere along the path of the urethra (Wese, Opsomer, Abi-Aad et al., 1994).
To recap, in a man the urethra is a canal in the form of a tube which runs the whole length of the penis and opens as a hole or slit positioned at the end of the glans. The primary functions of this tubular structure are to carry urine and to allow the passage of semen (Tortora & Grabowski, 1994).
4.1. General anatomical characteristics
Three anatomical characteristics have traditionally been associated with hypospadias (Paparel, Mure, Margarian et al., 2001), as follows:
– an ectopic urethral meatus
– an incomplete prepuce
– chordee
The unusual placement of the urethral meatus is a reliable anatomical characteristic of hypospadias. Hypospadic urethral openings may be located at a variable distance from the extremity of the glans. This ranges from a slightly displaced orifice under the ventral side of the glans to an orifice located in the perineum.
The incomplete prepuce refers to an excess of preputial skin on the dorsal side of the penis which is absent on the ventral side [7]. (This appears as a hooded foreskin covering the dorsal half of the glans only.)
This characteristic regarding the prepuce often accompanies hypospadias but is not always constant [8].
The term chordee refers to the existence of a ventral curve of the penis, especially noticeable during an erection. In general, the extent of chordee is relative to the degree of hypospadias.
In the last few years, some specialists (pediatric urologists) have opted for a more anatomical approach. Thus, as per Paparel et al (2001, p. 741), hypospadias can be defined as a ‘hypoplasy of the tissues forming the ventral side of the penis’. Anatomically, a penis known as hypospadic is characterized by an immaturity of the tissues (hypoplasy) situated on the inferior side of the penis: those forming the urethra, the corpus spongiosum and sometimes even the corpora cavernosae. The most distinct morphological signs of this diminished formative activity in these tissues are: a part of the urethra missing; a division in the corpus spongiosum (where it does not surround the existing portion of urethra); a ventrally incomplete prepuce; an absence of frenulum on the glans; and a chordee.
Sometimes, following an arrest of growth in the tissues forming the corpora cavernosae, under-development of the penis may occur [9] (Paparel et al., 2001).
4.2. Anomalies Associated With Hypospadias
Hypospadias appears most often in an isolated manner (Hencha-Razavi & Escudier, 2000 ; Larsen, 1996). However, it is known that other genital malformations or anomalies, some more serious than others, sometimes accompany this condition.
Alongside hypospadias, cryptorchidism [10] may also be present in the newborn male (Wese et al., 1994). Cryptorchidism may be defined as ‘the uni- or bi-lateral absence of the testicles in the scrotal cavity’ (Garnier & Delamare, 2000). The association of cryptorchidism with hypospadias (observed in around 9% of cases) may be understood in relation to the endocrinal process during testicular descent (passage of the testicles through the abdomen and into the scrotum) which is similar to the embryology of hypospadias (Huston, 2002).
More rarely, the penis may be combined with the scrotum [11] ; or the position of the scrotum may change place with the root of the penis (peno-scrotal transposition) (Avolio, 2002).
Hypospadias is most severe when accompanied by these genital anomalies (Eberle, Überreiter, Radmayr et al., 1993).
5. Diversity and Classification of Hypospadias
There is a diversity of hypospadias. As remarked by Arap et Mitre (2000, p. 304), hypospadias may be observed in a variety of configurations, varying from an ‘ambiguous aspect of the external genital organs’ to ‘a completely formed penis with only a superficial deficiency’.
5.1. Hypospadias or intersexuality ?
The broader issues of sexual ambiguity and intersexuality [12] may arise when the degree of severity of hypospadias is pronounced (e.g., with perineal hypospadias) and where other genital problems (e.g., cryptorchidism; under-developed penis) are added to the picture (Hutcheson, 2002).
In some cases it is necessary to carry out a series of examinations (e.g., palpation of the gonads, magnetic resonance imagery, caryotype) in order to determine the most probable sex of the child (Kaefer, Diamond, Hendren et al., 1999 ; Lapointe, Wei, Hricak et al., 2001 ; McAlleer & Kaplan, 2001).
However, in the vast majority of cases, the presence of hypospadias does not lead to doubt as to the male sex of the child (46XY) or to his acceptance as a boy (American Academy of Pediatrics [AAP], 2000 ; Wilson & Reiner, 1999 ; Zemel & Slover, 2002).
5.2. Named variations of hypospadias
Various classifications of hypospadias have been proposed, defined mostly by the location of the urethral meatus at birth. For example, one such scheme is shown below (Wese et al., 1994):
Names for variations of hypospadias / Possible locations of the urethral meatus:
1) Glanular / On the underside of the glans
2) Coronal / At the level of the glanular-preputial ridge [13]
3) Anterior penile / On the anterior third of the shaft of the penis
4) Median penile / On the middle third of the shaft of the penis
5) Posterior penile / On the posterior third of the shaft of the penis
6) Peno-scrotal / At the junction of the penis and scrotum
7) Scrotal / At the level of the scrotum
8) Perineal / At the level of the perineum
Over time, several different classifications of hypospadias have been suggested based on the position of the urethral meatus (Sheldon & Duckett, 1987). However, many pediatric urologists have adopted a particular classification developed, some thirty years ago, by a surgeon named Barcat (Barcat, 1973, quoted in Zaontz & Packer, 1997).
This classification, based on (possible) associated chordee, considers that hypospadias can only be classified after a surgical straightening of the penis has taken place [14].
Sheldon & Duckett (1987) contributed to the popularity of such a system, believing that there are 3 principal forms of hypospadias, within which are grouped different degrees of abnormality. These are known as anterior (or distal); median; and posterior (or proximal) (see Figure 6). In terms of frequency, the anterior forms are the most frequent (70% of cases), followed by posterior (20%) and median (10%).
FIGURE 6
Source: Weiner and Hensle (2000).