The internal oblique muscle in inguinal herniorrhaphy

The

Internal Inguinal

Oblique Muscle Herniorrhaphy

EUGENE A. GASTON, M.D., Framingham,

Massachusetts

mond [3], after observing the function of the muscIe by eIectrica1 stimuIation of its nerve supply at operation, referred to it as the inguina1 sphincter. He suggested that indirect inguina1 hernia resuIts from exposure of the interna inguinal ring to increased intra-abdominal pressure “onIy if the Iatter is suffIcientIy severe to overcome the sphincter, or if some incoordinated action of the inguina1 muscIes takes pIace.” ShortIy thereafter Keith [4], foIIowing simiIar muscIe stimuIating experiments, described the action as that of a shutter rather than a sphincter stating: “The underIying mechanism is simiIar to that which shuts the eyeIids; the Iower Iid, Iike Poupart’s Iigament, being aImost stationary.” Since then the terms “sphincter” and “shutter” have both been used to describe the function of this muscIe even though they suggest quite different degrees of effectiveness. This difference in terminoIogy is doubtIess the resuIt of observations of muscles which differ in configuration between individuaIs: If a muscIe arises at or media1 to the interna ring and then swings around the spermatic cord to insert into the pubic crest and tubercIe, it surrounds two-thirds or more of the interna ring and its action simuIates that of a sphincter. Origin IateraI to the interna inguina1 ring, on the other hand, causes it to function as a shutter, with Iess compIete contro1 of the interna ring. The degree of contro1 over the interna ring, whether sphincter-like or shutter-like, shouId and apparentIy does influence the deveIopment of indirect hernias. In this study the sphincter-Iike origin of the intern:11 obIique muscIe was present in 0nIy 28 per cent of indirect hernias, while the Iess effective shutterlike origin was present in 72 per cent. The type of insertion of the internal obIique muscIe is aIs important to its function as a sphincter or shutter, for an insertion into the

ORIGIN and insertion of the interna obIique muscIe in the groin are important to both the etioIogy and the cure of inguina1 hernias. Anatomic descriptions of this muscIe are IargeIy the resuIt of studies carried out in the Iaboratory on subjects without hernia [1,2]. For severa years accurate anatomic descriptions of the muscIes, as they were observed in living individuaIs with hernias, have been incorporated into the operative notes of patients undergoing inguina1 herniorrhaphy. The purpose of this paper is to present a study of this materia1 and a brief discussion of its significance.

T

in

HE

RESULTS Information regarding the origin and the insertion of the interna obIique muscIe was avaiIabIe in the notes of 213 operations. Figure I summarizes the resuIts of a study of these data. It wiI1 be noted that there are two types of origin and two types of insertion and that these may occur in any one of four combinations. The muscIe takes origin from the inguina1 Iigament or the subjacent fascia (or both) (I) at or beneath the spermatic cord at the internal inguina1 ring or (2) at a distance of from I to ring. OccasionaIIy 3- cm. IateraI to the interna it has no attachment media1 to the anterior superior spine of the iIium. The insertion of the interna obIique muscle may be into either the crest and spine of the pubic bone, as it is usuaIIy described in textbooks of anatomy or, aIternatively, into the side of the rectus sheath from I to 5 cm. above the pubic spine. RELATIONSHIP OF THE CONFIGURATION OF THE INTERNAL OBLIQUE MUSCLE TO THE ETIOLOGY OF INGUINAL HERNIAS The protection afforded the abdomina1 inguina1 ring by contraction of the interna obIique muscIe has Iong been known. In 1923 Ham569

American

Journal

of Surgery,

Volume

1o7.

April

1964

Gaston ARfSES

of Interna/

Ring, INSERTS

into Pubic Tubercfe

of INDIRECT Hernias

20.8%

I I. I % of DIRECT Hernias iO.O%of ARISES

atInternal Rinq,

INSERTS

/cm. or more Above Pubic Tube&e

20.4 % ot DIRECT Hernias 15.0 % of BILOCULAR

tcm. ormore Loterof to ht. Rinq, INSERTS

ARISES

I cm. ormoreLaterultoM

HERNJAS

Hernias

thto Pubic Tubercle

of DIRECT Hernios

5.5% 20.0

/!2%

ofALL

of INDIRECT Hernias

20.8%

“’

HERNMS

BILOCULAR Hernios

% of INDIRECT Hernjos

7.2

ARISES

124% &ALL

169% of ALL HERNIAS

X of BILOCULAR Hernias

Rihq, INSERTS

f cm. ormore Above Pubic Tubede

51.2 % of INDIRECT Hernias 63.0% 55.0

of DIRECT Hernias

X of BILOCULAR

545% of ALL

HERNIAS

Hernias

FIG. I. The internal obIique musde.

anatomic defects and (2) the restoration or improvement of inguina1 physiology. The anatomic defects are easiIy deaIt with: The peritonea1 sac shouId be compIeteIy eIiminated and the stretching or Iaceration of the transversaIis fascia, which is present in nearIy a11 hernias in aduIts, shouId be repaired. This is a11 that is accompIished in Cooper’s Iigament type of repair popuIarized by McVay and others [3-71. PhysioIogic restoration invoIves improving the inguina1 shutter or sphincter by cIosing the defect between the interna obIique muscIe and the inguina1 Iigament. In order to do this properIy, good exposure through an adequate incision is essentia1 so that both the origin and the insertion of the muscIe can be cIearIy delineated. After such exposure, and onIy then, can the two structures be accurateIy approximated both media1 and IateraI to the interna ring. When the interna obIique muscIe inserts high into the rectus sheath, it may be necessary to approximate the rectus sheath to the inguina1 Iigament for a short distance in order to bring the interna obIique muscIe down to the inguina1 Iigament. The effectiveness of the inguina1

pubic crest and tubercIe provides better circumferential controI of the interna ring than does insertion into the side of the rectus sheath. Insertion into the pubic crest and tubercIe has the added advantage that HesseIbach’s triangIe is thereby partiaIIy reinforced. The importance of this reinforcement is emphasized by the fact that onIy 16.6 per cent of direct hernias occurred in individuals whose muscIes were so inserted. When the interna obIique muscIe takes origin IateraI to the interna ring and inserts into the side of the rectus sheath above the pubic tubercIe, there is no sphincteric action, incompIete shutter action and no reinforcement to HesseIbach’s area. The more IateraI the origin and the higher the insertion, the greater are these deficiencies. It is not surprising that the Iargest percentage of a11 hernias, indirect, direct and biIocuIar, faIIs into this group. IMPORTANCE

OF

INTERNAL REPAIR

THE

CONFIGURATION

OBLIQUE OF

MUSCLE

INGUINAL

OF

THE

TO THE

HERNIAS

The surgica1 repair of inguina1 hernias shouId have two aims: (I) The remova or repair of 570

InguinaI

Herniorrhaphy

sphincter or shutter can be safeIy enhanced by making the opening for the spermatic cord very tight. Firm union between the internal oblique muscle and the inguina1 ligament can be assured by the use of Iiving aponeurotic sutures fx)th medial and lateral to the interna ring [8].

2.

3.

ST_MMARY

4.

I.

A study of the anatomic configuration of the inguinal portion of the internal oblique muscle as it occurs in living patients with inguinal hernias is presented. 2. The relationship of the function of this muscle to the cause and cure of inguina1 hernia is Ix-ieflg discussed.

5.

6.

7.

REFEREhTCES I. Avon, B. J., MORGAU, Surgical anatomy of

upon a study of qx~ body-halves. Surg. C;ynec. PF Obst., I I I : 707, 1960. NYHUS, L.. hf., COPGDO~-,R. E. and I~ARKINS, II. N. Clinical experiences with preperitonea1 hernial repair for all types of hernia of the groin. .4m. J. Surg., TOO: 234, 1960. H~ar~ouo, T. E. The aetology of indirect inguinal hernia. Larrcet, I: 1206, 1923. KEITH, A. On the origin and nature of hernia. Brit. J. .Sq?., I 1: 455, 1924. hlcV~y, C. B. The Pathologic Anatomy of the .kIore Common IHernias and Their Anntom~c Repair. Springfield, Ill., 1954. Charles (1 Thomas. ~~cVAY, C. B. and CIIAPP, J. D. Inguinal and femoral hcrnioplasty: the ewduation of a basic concept. Ann. Surg., 148: 499, 1958. GI
531, 1959. 8. GASTOU, E. A. Living aponcurotic sutures to repair inguinal hernias. Arch. Surg., 85: 80, 1962.

E. H. and IMCVAY, C. B. the inguinal region based

571