Cremasteric Muscle Hypertrophy Accompanies Inguinal Hernias in Children

By Paul Brisson, Haroon Pate& and Neil Feins Boston, Massachusetts

Purpose: The physical finding of a thickened spermatic cord comparison. The biopsy specimens were evaluated by a as indicator of an inguinal hernia in children is well docu- pathologist unaware of the hypothesis. mented. This thickening has been attributed to the presence of a hernia sac. Based on our clinical observations, cremas- teric fibers appeared thickened in the presence of an inguinal hernia. The authors postulated that hypertrophy of cremas- tericfibers contributed to the physical finding of cord thicken- ing.

Methods: The authors evaluated 18 patients ages 5 months to 9 years, 17 boys and one girl. Each patient was found to have a unilateral inguinal hernia with palpablethickened cord on the affected side. The contralateral side contained no detectable hernia or palpable cord thickening. Each patient underwent repair of the clinical hernia and exploration of the contralateral groin. Cremasteric fiber biopsy sections were taken from both sides for cross-sectional measurement and

Results: In 15 of 18 patients microscopic measurement of the cremasteric fibers showed hypertrophy on the side of the clinical hernia when compared with the contralateral side. The contralateral side was found to have either no hernia or a small patent or obliterated processus vaginalis.

Conclusion: The authors conclude that the palpable thicken- ing of the spermatic cord, the “silk glove sign,” in most cases is caused not only by an empty hernia sac but also by hypertrophied cremasteric muscle fibers. J Pediatr Surg 34:1320-1321. Copyright 6 7999 by W.B. Saunders Company.

INDEX WORDS: lnguinal hernia, hypertrophied cremasteric muscle fibers.

I N THE ABSENCE of an obvious bulge, diagnosis of an inguinal hernia in children can be difficult. The

silk glove sign and the thickened spermatic cord sign are two physical findings originally described by Ladd and Gross’ that can aid in the diagnosis of an inguinal hernia. The silk glove sign refers to a sensation imparted to the examining finger that is similar to that obtained by rubbing together two layers of silk. This sign results from the rubbing together of the two surfaces of the empty sac. The thickened spermatic cord sign is thought to be secondary to the presence of the empty hernia sac. This sign also is, at times, referred to as the silk glove sign.2-4 Clinical observation led us to suspect that spermatic cord thickening actually is secondary to the combination of an empty hernia sac and hypertrophied cremasteric muscle fibers.

MATERIALS AND METHODS

After discussion and written consent were obtained, we evaluated 18 patients, 17 boys and one girl, ages 5 months to 9 years (Table 1). To enter the study the patients had to meet the following criteria: unilateral

From the Division of Pediatric Surgery, The Floating Hospital for Children, Boston, MA.

Address reprint requests to Neil Feins, MD, Department of Pediatric Surgery, 750 Washington St, NEMC #281, Boston, MA 02111.

Copyright o 1999 by WB. Saunders Company 0022-3468/99/3409-0003$03.00/O

inguinal hernia on physical examination and palpable thickened cord on the hernia side only. Each patient entered into the study underwent repair of the clinical hernia and exploration of the contralateral groin. For purposes of this study, a groin was considered “negative” if there was no hernia or a small patent or obliterated processus vaginalis. Cremasteric fiber biopsy specimens were taken bilaterally off the spermatic cord in the male patients and the round ligament in the case of the one female patient. Biopsies were performed under magnification leaving the majority of the cremasteric muscle intact. The specimens were submitted to pathology for cross-sectional measurement of individual muscle fiber diameter under light microscopy using a micrometer. The biopsy specimens were evaluated by pathologists who were unaware of the hypothesis.

RESULTS

Fifteen of 18 patients were found to have hypertrophy of the cremasteric fibers on the hernia side when com- pared with the negative side (Table 1). Of the 3 patients who were found to have no difference in the size of the cremasteric fibers, one was the only girl in the study. The other 2 patients were a 5month-old boy and a 5year-old boy.

DISCUSSION

Spermatic cord thickening in the presence of an inguinal hernia in children is well documented.‘+ This thickening previously has been attributed to the presence of a hernia sac.’ The reliability of cord thickening in the diagnosis of inguinal hernias in children is variable.3J

1320 Journal of Pediatric Surgery, Vol34, No 9 (September), 1999: pp 1320-I 321

MUSCLE HYPERTROPHY AND INGUINAL HERNIA 1321

Table 1. Demographic Data

Cremasteric Fibers

Herma Side Contralateral Side Patient No. Age (id (wl

1 3mo 11.8 11.48 2* 5mo 6.5 6.5

3 4mo 15.1 10

4 1 vr 22.9 11.4

5 2 vr 39 14

6 2 vr 19 12

7 2.5 yr 21 12 8 3vr 26.4 19.2

9 3vr 13 7

10*t 3vr 22 24

11 4vr 21.8 17.7

12 4vr 13 7

13* 5vr 7 7

14 5vr 13 7

15 5vr 23 9.8

16 6 vr 24.8 13.3

17 7vr 9.8 7

18 9 vr IO 7

*No difference.

tfemale.

fascia fuse. The deep layer of the cremasteric fascia is intimately related to the underlying internal spermatic fascia of the spermatic cord and scrotal contents.7 The cremasteric muscle is innervated by the genital branch of the genitofemoral nerve. Although these fibers are com- posed of striated muscle, they are not under voluntary control. The word cremaster is from the Greek kremash- tui, “to suspend.” The primary function of these fibers in boys is elevation of the testis toward the superficial inguinal ring for temperature control. In girls the cremas- teric fibers encircle part of the round ligament.

Palpable spermatic cord thickening is a physical find- ing that can be identified with practice. The middle finger is used to roll the spermatic cord over the pubic tubercle. In the presence of an inguinal hernia, the cord frequently will feel thickened in comparison with the normal side. With experience, even bilateral cord thickening can be identified with this method.6 In our practice, a thickened spermatic cord may have some influence on the decision to perform a hernia repair.

Although it would seem obvious that the hernia sac is the primary contributor to this thickening, our clinical obser- vations suggested that hypertrophied cremasteric fibers also contributed to this thickening.

Cremasteric muscle fibers are derived from the internal oblique aponeurosis, muscle, and fascia and perhaps the transverse muscle of the abdomen. This muscle is unique in that at its cranial-lateral aspect the fibers are arranged in a sheet, while distally at its passage through the external ring, the fibers form long loops that frequently are widely separated. Distal to the external ring, the spermatic cord is invested completely with cremasteric muscle and fascia. Where cremasteric muscle fibers are absent, the superficial and deep lamina of the cremasteric

Cremasteric muscle hypertrophy in the presence of an inguinal hernia has not been described previously. The etiology of the cremasteric muscle hypertrophy is not clear. In general, muscle hypertrophy results from re- peated stress. Although only speculation, the hernia sac could be considered an additional stress to the function of the cremasteric muscle.

There have been no previous studies to determine whether cremasteric fiber size will vary between sides in children with no groin pathology. The diagnosis and treatment of inguinal hernias in children continues to be a topic of substantial controversy. This report redefines a well-documented physical finding and adds anatomic and physiological information to the study of inguinal her- nias.

REFERENCES 1. Ladd WE, Gross RE: Abdominal Surgery in Infancy and Child-

hood. Philadelphia, PA, WB Saunders, 1941

2. Rowe M, Lloyd D: Inguinal hernia, in Welch K (ed): Pediatric Surgery. Chicago, IL, Year Book Medical Publishers, 1986, p 780

3. Raffensperger J: Inguinal hernia, in Ratfensperger J (ed): Swen- son’s Pediatric Surgery. New York, NY, Appleton and Lange, 1990, p 124

4. Weber T, Tracy T: Groin hernias and hydroceles, in Ashcraft K,

Holder T (ed): Pediatric Surgery. Philadelphia, PA, Saunders, 1993, p 564

5. Johnstone J: Hernia in the neonate, in Freeman N (ed): Surgery of the Newborn. Edinburgh, Scotland, Churchill Livingstone, 1994, p 324

6. Dennison W: Hernia and hydrocele, in Dennison W (ed): Surgery in Infancy and Childhood. Edinburgh, Scotland, E & S Livingstone, 1967, p 309

7. Redman J: Applied anatomy of the cremasteric muscle and fascia. J Urol 156:1337, 1996