APPLIED ANATOMY

R. Bendavid

Sliding hernias

Received: 1 April 2002 /Accepted: 25 April 2002 / Published online: 10 July 2002� Springer-Verlag 2002

Introduction

Nothing so tests the surgeon’s knowledge of the anat-omy of the inguinal region as a chance encounter witha sliding hernia. If Condon’s [4] dictum ‘‘The anatomyof the inguinal region is misunderstood by some sur-geons at all levels of seniority’’ is correct, it is safe tosay that sliding hernias are understood by few surgeonsat any level of seniority. Few surgical procedures havehad so many illustrations attempting to explain themechanism of the ‘‘slide’’ and its surgical treatment; yetthey have served only to complicate and confuse thepicture. What surgeon about to start a practice has notworried about a strangulated sliding hernia presentingin the middle of the night! ‘‘Sliders’’ are simple to treat– we will see why.

Definition

A sliding hernia is a protrusion through an abdominalwall opening of a retroperitoneal organ, with or withoutits mesentery, with or without an adjacent peritonealsac. This organ may be the cecum, ascending colon, orappendix on the right side, the sigmoid colon on the leftside, or the uterus, fallopian tubes, ovaries, ureters, andbladder on either side.

History

Galen (130–200 AD) gave us the first description of asliding hernia involving the cecum. Rousteus mentioned

the condition in 1631; Spiegel reported cases in 1645 and1680, followed by Arnaud (1732), who managed an ‘‘oldscrotal hernia with great difficulty, removing, in theprocess, the cecum and part of the colon and ileum in apatient who eventually recovered!’’ [11]. Scarpa [20] in1814 reported a cecum forming part of the wall of ahernial sac. William Mitchell Banks [1] (1843–1904)coined the term ‘‘landslide of the cecum’’; he was alsothe first proponent in England of complete removal ofthe hernial sac, declaring that ‘‘the great object of thewhole proceeding is to restore a uniform surface to theperitoneal wall and hence the higher up the sac is tied,the better the chance of this being permanent.’’ Ironi-cally, this thoroughness in excising the sac may well havecontributed to the dangerous reputation of sliding her-nias. Morris [16] (1895), Hotchkiss [10] (1909), Zim-merman and Laufman [23] (1942), and Maingot [14](1961) emphasized the need to free the sliding herniafrom the spermatic cord and to return the sac and viscusto the abdominal cavity.

The idea of reperitonealization of a viscus outlined byBevan [2] (1930) and many others can now be safely andassuredly discarded. The Laroque [13] counterincision(1932) is now considered unnecessary, since the con-vincing reports of Ryan [18, 19] and Glassow [6] andconfirmation by Welsh [22].

Classification

The classification of sliding hernias in the past may havebeen partly responsible for some confusion. Since thereare three types of sliding hernias, it is probably simplestto call them types I, II, and III in descending order offrequency.

• Type I: any hernia in which part of the peritoneal sacis made up by the wall of a viscus. This is the com-monest type and accounts for nearly 95% of slidinghernias. This type has also been referred to as intra-mural, parasaccular, and visceroparietal (Fig. 1).

Hernia (2002) 6: 137–140DOI 10.1007/s10029-002-0065-1

R. BendavidDepartment of Surgery,Laniado General Hospital, Netania IsraelE-mail: rbdavid@netvision.net.ilTel.: +972-9-8604673Fax: +972-9-8609517

• Type II: any hernia containing a retroperitoneal viscusand its mesentery, in which the mesentery forms partof the wall of the peritoneal sac. About 5% of slidinghernias are of this type, which has also been namedintrasaccular, extrasaccular (a misnomer), and vis-ceromesenteric (Fig. 2).

• Type III: a protrusion of the viscus itself; the perito-neal sac may be very small or even absent. This is therarest type and is found in only one of 8,000–10,000hernia. This type is the most treacherous and its di-agnosis requires a high index of suspicion. It has beendescribed as extraperitoneal, sacless, and extrasaccu-lar sliding hernia (Fig. 3).

An additional type, although not truly a sliding hernia, isthe so-called ‘‘incipient slider.’’ When the sac is opened,one can see the viscus, but it has not yet entered theinternal inguinal ring.

Pathophysiology

The mechanism whereby the viscus or viscera ‘‘slide’’has not been fully explained. Before the slide can take

place, however, there must be a widening of the internalinguinal ring; this is the precondition of an indirect in-guinal hernia.

Sir Arthur Keith (1866–1955) proposed that, devel-opmentally, the cecum and ascending colon do notcomplete their rotation to the right side, and thus thececum slides inferiorly toward not only the right but alsothe left internal inguinal ring [11]. Moschowitz [17] in1925 presented his ‘‘pulling-pushing’’ mechanismwhereby an inguinal sac enlarging through a wideninginternal ring exerts a pull on the cecum or ascendingcolon, whereas anterior structures such as the urinarybladder would be pushed through the posterior inguinalwall by intra-abdominal pressure. Graham [8] of To-ronto suggested another possible mechanism: over longperiods the layers of the mesentery (especially of thesigmoid) separate, allowing the bare posterior aspect ofthe viscus to slide and protrude through an enlargedinternal ring. The common initial factor is always thewidened internal inguinal ring.

Clinical characteristics

As observed by Ryan [18, 19], Glassow [6], and Welsh[22], sliding inguinal hernias account for 8% of groinhernias, with a left to right ratio of 4.5 to 1. Maingot[14], however, found a 1.5 to 1 preponderance of right-sided sliders. In the series of Ryan et al. [18, 19] 8%were bilateral, and women made up only 1% of the3,000 patients analyzed; the average age of patientswas 59.3 years, compared to 51 years for nonslidinghernias. After the age of 50 years the incidence ofsliding hernias is 3.5 times more frequent. In 9% ofpatients there is a history of previous inguinal surgery,and 94% of sliders are easily reducible preoperatively.The size of these sliders is categorized as small (16%),medium (44%), and large (40%). Delay before comingto surgery is 11.8 years on average. The incidence ofsliding inguinal hernias increases with the age of thepatient, being nearly zero before the age of 30 yearsand increasing to as much as 20% after the age of70 years.

Fig. 2. Type II sliding inguinal hernia. In this case the mesenteryforms a part of the posterior wall of the sac. Note that part of theanterior wall of the cecum is also forming part of the posterior wallof the sac

Fig. 3. Type III sliding inguinal hernia: the sac is somewhatminiscule and may easily be overlooked. This is the most dangeroustype, but fortunately the rarest (1/8–10,000)

Fig. 1. Type I sliding inguinal hernia. The posterolateral aspect ofthe sac is made up of the cecum and ascending colon

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In the pediatric population boys are not subject tosliding hernias, whereas in ‘‘female pediatric patients,inguinal hernias are usually sliding hernias’’ with themesosalpinx adherent to one side of the sac (type II) [12].Frequently the ovary and/or fallopian tube is involved.The round ligament may be resected, but the sac itselfmust not be ligated ‘‘high’’ lest the ovary/tube be dam-aged. The incidence of sliders in girls was 21% in twoseries by Goldstein and Potts [7] and Gaus [5].

Discussion and operative technique

As early as 1955 Ryan [18] stated that ‘‘too great anemphasis had been placed on removal of the hernialsac.’’ To the surgical section of the Toronto Academy ofMedicine the hallowed ground of Gallie and Graham,this was heresy. Nevertheless, Ryan substantiatedhis statement with a series of 313 cases: ‘‘In 47% ofthe patients no sac was removed, in 43% only a partof the sac was removed. In the remaining 10% of thecases, the sliding hernia was small and most of the sacwas removed’’ [18].

Ryan also emphasized that the important step in theoperation is to reconstruct the posterior inguinal wall inorder to confine the sliding elements of the hernia to thepreperitoneal space. This was achieved with a recurrenceof less than 1%, at a time when one report from Phila-delphia admitted to a recurrence rate of 55% [18]! Welsh[22], as if to consecrate his colleague, validated Ryan’slarge series with a yet larger series of 3,000 cases. Thesewere culled from among 4,516 patients: incipient sliderswere excluded (25%) as well as direct sliding hernias(1.5%) and ‘‘unconfirmed’’ sliding hernias (3%; by‘‘unconfirmed’’ was meant that the sac was not openedfor confirmation of the sliding nature of the hernia). Themethod of repair used was the Shouldice technique, butthe Bassini repair and tension-free repairs (except for theplug) would have been appropriate. The plug, which hasa depth of 4 cm, would cause concern, as it would be incontact with either sliding bowel or an iliac vessel. Theiliac artery on the supine patient is usually 1–2 cm deepto the internal ring.

In brief, the cremaster muscle is divided longitudi-nally for better access to the spermatic cord and internalring. The cord is then separated from the sliding herniasac, and the dissection stays close to the cord, its in-vesting fascia and adipose tissue. The internal ring, al-ready wide, allows separation of the transversalis fasciaabout the neck of the sac. It is important to realize atthis stage that the posterior lamina of the transversalisfascia may in itself form a constricting ring around thehernia, separate from the anterior lamina of the trans-versalis fascia. Constricting tissue, if scarred, can besafely incised at the anterior or medial aspect of theconstricting ring. The viscus is invariably found on the

posterior and lateral aspect of the internal inguinal ring.Gentle dissection in this area frees all adhesionsand allows sac and sliding viscus to return to thepreperitoneal space. If it can be done safely, the sac maybe opened for inspection and then closed; it need not beresected. High ligation of the sac should never be at-tempted, as it is not necessary. A counterincision hasnever been needed. If in doubt as to the nature of athick-walled sac, do not open it! It could be the wall ofbowel, as seen in the sacless variety or type III slider.The remainder of the operation is devoted to the re-construction of the posterior inguinal wall by the chosentechnique of the operating surgeon.

Follow-up revealed 16 recurrences out of 3,000 op-erations, an incidence of 0.5%. Six were femoral hernias,five direct inguinal hernias, and four appeared to befemoral hernias but were not operated on; only one wasa true recurrent sliding indirect inguinal hernia.

Complications

Two patients died following surgery; one from a coro-nary thrombosis on the third postoperative day, theother from a cerebral hemorrhage 2 weeks after surgery.Not a single patient developed a bowel obstruction.Wound infection remained constantly below 1%.

Special considerations

In acute de novo strangulation, or strangulation of achronic irreducible sliding inguinal hernia, the adhe-sions, inflammation, and edema between the cord andthe viscus may blur the anatomical picture. The viscusmay not be safely separated from the cord without therisk of perforation, which carries an associated mortalitybetween 6% and 60%, depending on the age of thepatient, the delay in diagnosis, and the degree of vas-cular compromise [15, 21]. It would not be unreasonablein these conditions to consider division of the cord, asclose to the internal inguinal ring as feasible. The col-lateral circulation of the testicle is so abundant that lossof the testicle occurs in 0–37% of the cases, at the veryworst [3, 9]. It would be, in any case, a small price topay, considering the far graver risk of perforation. Themedicolegal aspects of this situation should be explainedto the patient prior to surgery so that the consent formsare signed with full understanding of possible perioper-ative decision-making.

Sliding inguinal hernias are common, particularly inthe aging population. They need not any longer engen-der the apprehension they once did, thanks to the con-tributions of Ryan. The brevity and simplicity of thisreview mirrors the present status of this once fearsomehernia.

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References

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