Congenital Spigelian Hernia and Undescended Testis: Pitfalls in the Transformation of a “Coexistence” to “Sequence” and “New Syndrome”

We read with great interest the article “Undescended testis accompanying congenital spigelian hernia: is it a reason, a result, or a new syndrome?” by Bilici et al.[1] Their inquiry is certainly valid. However, we offer objections to the reported counts and association measures, as well as to the adoption of the terms “sequence” and “syndrome” for the coexistence of these two anomalies.

1. Inaccurate count of cases with both spigelian hernia (SH) and undescented testis (UT): In Table 1 of the article by Bilici et al,[1] 15 cases of SH with UT are listed before Durham and Ricketts[2] (2006); however, these authors reported 16 cases before their own. This makes a difference of one case possibly missing here.

Also, the cited review by Moles Morenilla et al[3] (2008) reports a total of 16 cases with SH and UT (including the cases of Durham and Ricketts) as the most recent until that date. Adding the five new cases reported here, we come to a sum of 21, not the 24 listed by Bilici et al. This makes a difference of three additional cases.

Such discrepancies are not uncommon in reports of cases with retrospective review of the literature.

2. Association measures: A “rate of coexistence” of 60% is reported in this article (24 cases with UT within a total of 40 cases with SH). It seems that these 40 cases are the same 40 cases reviewed by Moles Morenilla et al[3] (2008) because no new SH cases are found in PubMed since then. However, in the latter article, females are included in these 40 cases. If females are included here, the 24:40 ratio is evidently erroneous.

The earlier association measures offered in the article also invite criticism. Moles Morenilla et al[3] (2008) reported a ratio (percentage) of 48.4% (16 UT cases in 33 patients with SH); if this ratio used cases instead of patients in the denominator (40 SH in 33 patients), it would be 40%. When only males were taken into consideration, this rate increased to 61.5%. Durham and Ricketts[2] (2006) restricted this association to male infants and reported an “association rate” of 75%, which increased to 80% by the addition of their own cases.

Previously, Raveenthiran[4] (2005) reported a ratio of 28% (11 UT cases in 40 SH cases; SH taken altogether). Finally, Al-Salem[5] (2000) reported a “rate” of 19% (seven UT cases in 37 patients with SH), but included traumatic and postoperative cases, male and female patients, with ages reaching to15 years old.

It is evident that reported association measures vary incredibly, from 19 to 80%, depending on how they are conceived (i.e., in the denominator of the ratio, SH cases are regarded either all together, congenital and traumatic/postoperative, or congenital cases only, or in infant males only). Also, for the sake of correct terminology, we remind that the term “rate” refers to data collected over a period of time, and, when reporting cases recorded though all years, the association measure should be restricted to a ratio or percentage.

No matter the terminology, these association measures aim to establish a relationship of the two anomalies. During surgery, the relationship of the two anomalies is “evident” because they are both present in the operating field. However, in statistics, an “association” would render the two anomalies statistically dependent, the one upon the other. A significant association has to be proved; otherwise, the random coexistence of the two anomalies cannot be excluded. However, here we cannot calculate a 2 × 2 contingency table: the number of cases with UT through the years, and the number of cases without UT and SH are unknown.

Therefore, it is clear that the ratio (SH⁺UT):SH⁺(SH⁺UT) (24:40 here) is wrong in principle as a measure of the association of the two conditions because no significant association has been proved in the first place. This ratio only expresses just the proportion of cases of “congenital SH accompanied by UT” within the total number of reported cases of SH. It does not support neither that SH is accompanied by UT nor that UT is accompanied by SH. Especially, the latter is outrageous, and Bilici et al thoughtfully refer to it in their criticism of Raveenthiran, but only as an argument against the suggested causative mechanism. Nevertheless, at the end of the first paragraph of their discussion, we read the “rate of UT cases accompanied by SH … was determined to be 60%,” which is not correct, as they admit latter in the text.

In conclusion, if a significant association is not shown, the coexistence of the two anomalies can be just random, and all these association measures are meaningless.

3. Causative mechanisms: The choice of the term “syndrome” to describe the coexistence of congenital SH and UT implies that the anomalies have a known or presumed common cause.[6] Other authors have proposed various presumed mechanisms to support the conjecture of two anomalies, which Bilici et al nicely criticize here. However, the three reported mechanisms refer to the causative relation of either congenital SH with UT or the reverse, UT with congenital SH. Bilici et al are right to wonder what is the cause and what is the result, and to ask for elucidation of the causal relation to name this coexistence a “sequence.” However, here again, a significant association (congenital SH causes UT or vice versa) has to be established in advance.

None of the suggested mechanisms offers a common cause for the coexistence of congenital SH and UT; each attempts to explain a one-way causative relation. The fact that the proposed mechanisms “are not satisfactory”—as Bilici et al characterize them (a statement with which we agree)—is not an argument for their use of the term “syndrome.” In our opinion, the mistake results from the definition of “syndrome” adopted by this article, stating that “the findings seems to be independent from each other but appear as a single disease when they coexist.” We argue that the two anomalies are dependent on each other, that is, statistically they should have a significant association between them; in addition, embryologically, they should be caused by a common mechanism. If both these requirements are not fulfilled, the term “syndrome” is not justified.

Apart from these concerns, we disagree with Bilici et al that the inguinal canal may be absent and, moreover, that this “absence” constitutes an element of the congenital SH–UT “syndrome.” The suggestion of an inguinal canal absence was first made by Rushfeldt et al[7] (based on the reports of others) to complete their intraoperative observation that the gubernaculum was absent in UT coexisting with congenital SH. The inguinal canal cannot be absent: this anatomic entity is present before testicular descent and exists in both male and female.[8] Evidently, no dissection to prove inguinal canal absence was ever undertaken (and of course should not be performed) during surgery; this remains a task for the surgical anatomist who might be able to obtain cadavers of infants with SH and UT.

• References

• 1 Bilici S, Güneş M, Göksu M, Melek M, Pirinçci N. Undescended testis accompanying congenital Spigelian hernia: is it a reason, a result, or a new syndrome?. Eur J Pediatr Surg 2012; 22 (2) 157-161
• 2 Durham MM, Ricketts RR. Congenital spigelian hernias and cryptorchidism. J Pediatr Surg 2006; 41 (11) 1814-1817
• 3 Moles Morenilla L, Gómez Rubio D, Sánchez Blanco JM, Galindo Galindo A, Recio Moyano O, Brox Jiménez A. [The new congenital Spigelian hernia and cryptorchidism syndrome. Analysis of 16 cases]. Cir Esp 2008; 84 (3) 154-157
• 4 Raveenthiran V. Congenital Spigelian hernia with cryptorchidism: probably a new syndrome. Hernia 2005; 9 (4) 378-380
• 5 Al-Salem AH. Congenital spigelian hernia and cryptorchidism: cause or coincidence?. Pediatr Surg Int 2000; 16 (5–6) 433-436
• 6 O'Rahilly R, Muller F. Human Embryology and Teratology. 3rd ed. New York: Wiley-Liss; 2001: 127-128
• 7 Rushfeldt C, Oltmanns G, Vonen B. Spigelian-cryptorchidism syndrome: a case report and discussion of the basic elements in a possibly new congenital syndrome. Pediatr Surg Int 2010; 26 (9) 939-942
• 8 Biasutto SN, Repetto E, Aliendo MM, Borghino VN. Inguinal canal development: the muscular wall and the role of the gubernaculum. Clin Anat 2009; 22 (5) 614-618