Hernia Sac

Background

A hernia is a very common medical condition afflicting all ages and both sexes. A hernia is literally a weakening or tear in the wall of the abdomen. These hernias may be a congenital defect or acquired as a result of repeated trauma. A hernia most commonly presents with a bulge under the skin, sometimes accompanied with pain during lifting of heavy objects. The daner of a hernia is the possibility of a portion of the intestine becoming entrapped and strangulated, known as incarceration, leading to a surgical emergency.

OUTLINE

Epidemiology

Pathogenesis

Gross Appearance and Clinical Variants

Histopathological Features and Variants

Differential Diagnosis

Prognosis

Treatment

Commonly Used Terms

Internet Links

EPIDEMIOLOGY CHARACTERIZATION

INCIDENCE/PREVALENCE See Clinical Variants

AGE See Clinical Variants

SEX See Clinical Variants

PATHOGENESIS CHARACTERIZATION

CALCIUM

Total calcium content of sacs associated with inguinal hernia, hydrocele or undescended testis reflects differences dictated by programmed cell death.

Tanyel FC, Ulusu NN, Tezcan EF, Buyukpamukcu N.

Department of Pediatric Surgery, Hacettepe University, Faculty of Medicine, Ankara, Turkey.

Urol Int 2003;70(3):211-5 Abstract quote
INTRODUCTION: Inguinal hernia and hydrocele are suggested to result from the persistence of smooth muscle (SM) which should undergo programmed cell death (PCD) after presenting transiently to propel the testis. Since Ca(2+) is involved in PCD, the Ca(2+) contents of the peritoneum and sacs associated with undescended testis, inguinal hernia and hydrocele were determined and compared.

MATERIALS AND METHODS: Sacs were obtained from boys with undescended testis (n = 11), inguinal hernia (n = 22) and hydrocele (n = 10), and girls with inguinal hernia (n = 7). The calcium content of the sacs and peritoneal samples (n = 6) was determined through atomic absorption spectrophotometry. Calcium contents were compared according to their sources using the Mann-Whitney U test and p values of <0.05 were considered significant.

RESULTS: While revealing similar Ca(2+) contents as the peritoneum, sacs associated with undescended testis and hydrocele contained more Ca(2+) contents than the sacs of boys and girls with inguinal hernia (p < 0.05).

CONCLUSIONS: Sacs associated with inguinal hernia, which are known to contain SM all around the mesothelial layer, contain the least Ca(2+). Despite the decrease in SM, sacs associated with hydrocele contain more Ca(2+). Since PCD is associated with Ca(2+) overload and inhibition of Ca(2+) load inhibits PCD, differences in Ca(2+) content may reflect the inhibition of PCD at different stages and for different reasons in inguinal hernia or hydrocele of childhood.

COLLAGEN SYNTHESIS

Synthesis of type I and III collagen, expression of fibronectin and matrix metalloproteinases-1 and -13 in hernial sac of patients with inguinal hernia.

Klinge U, Zheng H, Si ZY, Schumpelick V, Bhardwaj R, Klosterhalfen B.

The Department of Surgery, The Technical University of Aachen, Germany.
Int J Surg Investig 1999;1(3):219-27 Abstract quote
Since many years the importance of a weakness of the soft tissue for the development of hernias is discussed controversially. The tensile strength of the tissue is supposed to depend largely on the varying proportion of type I collagen with its high tensile strength and the immature type III collagen. Their relation is regulated by several collagenases, mainly matrix metalloproteinases-1 and -13 (MMP-1 and MMP-13), whereas fibronectin plays a key role for the adherence of cells within the extracellular matrix.

The aim of this study was to investigate whether an alteration in type I and type III collagen synthesis, amounts of MMP-1 and MMP-13 and the expression of fibronectin were associated with the development of inguinal hernia. We analysed the hernial sac of patients with indirect (n = 9) and direct (n = 7) inguinal hernias and peritoneum in controls (n = 7) by immunohistochemistry and Western blot analysis. The results showed that the ratio of relative amount of I/III collagen was markedly decreased in patients with either indirect or direct hernias as compared with controls (p < 0.001) with a concomitant increase in type III collagen synthesis. MMP-13 was expressed neither in the hernial sac nor in the peritoneum of the controls, but the positive reactions of MMP-1 were found in the surface of the subserosa of the hernial sac in patients with indirect or direct hernias without any difference compared to controls.

Furthermore, the relative amount of fibronectin in patients with either indirect or direct hernias is not significantly different from controls (p > 0.05). In regard to the known alterations of the collagen metabolism in fascia and skin of hernia patients the changed collagen I/III ratio with its increase of type III collagen in hernial sacs support the presence of a systemic disturbance of collagen metabolism. The absence of changes of the expression of collagenases (MMP-1, MMP-13) and the constant levels of fibronectin underline the central role of collagen synthesis for the development of indirect or direct hernias.

MYOFIBROBLASTS

Myofibroblasts defined by electron microscopy suggest the dedifferentiation of smooth muscle within the sac walls associated with congenital inguinal hernia.

Tanyel FC, Muftuoglu S, Dagdeviren A, Kaymaz FF, Buyukpamukcu N.

Department of Paediatric Surgery, University, Faculty of Medicine, Ankara, Turkey.
BJU Int 2001 Feb;87(3):251-5 Abstract quote
OBJECTIVE: To ascertain the presence of myofibroblasts in sacs associated with inguinal hernia in children, through an ultrastructural evaluation using electron microscopy.

MATERIALS AND METHODS: Sacs were obtained from 10 boys and 10 girls (of similar age, approximately 45 months) with inguinal hernia and processed for electron microscopy. Thin sections were examined specifically for the presence of myofibroblasts.

RESULTS: The ultrastructural evaluation showed myofibroblasts with classical electron microscopic features within all of the sacs, regardless of the gender of origin.

CONCLUSION: The persistence of smooth muscle hinders the obliteration of the processus vaginalis; myofibroblasts are found in association with smooth muscle and thus such cells within the sac walls seem to originate from the smooth muscle, reflecting the dedifferentiation of smooth muscle. This dedifferentiated state may represent attempted apoptosis, which usually causes the disappearance of the smooth muscle and obliteration of the processus vaginalis after the descent of the testis into the scrotum.

SMOOTH MUSCLE

Inguinal hernia revisited through comparative evaluation of peritoneum, processus vaginalis, and sacs obtained from children with hernia, hydrocele, and undescended testis.

Tanyel FC, Dagdeviren A, Muftuoglu S, Gursoy MH, Yuruker S, Buyukpamukcu N.

Department of Pediatric Surgery, Hacettepe University, Faculty of Medicine, Ankara, Turkey.

J Pediatr Surg 1999 Apr;34(4):552-5 Abstract quote
BACKGROUND/PURPOSE: Histological structures of peritoneum, processus vaginalis, and sacs obtained from girls with inguinal hernia and boys with inguinal hernia, hydrocele, and undescended testis have been compared through immunohistochemical features to evaluate if any clue descriptive for the etiology of inguinal hernia exists.

METHODS: Parietal peritoneums (n = 6), processus vaginalises (n = 4), female hernia sacs (n = 5), male hernia sacs (n 12), and sacs from hydrocele (n = 5) and undescended testis (n = 9) were stained with indirect immunoperoxidase method. Anti-CD9, CD26, CD29, CD31, CD36, CD44, CD49a, CD49b, CD49c, CD49d, CD49e, CD49f, CD54, CD55, CD56, CD62E & P, CD71, CD98, CD102, CD106, CD146, CD151 monoclonals and NFL-NPH, S-100 antiserums were used. The histological structures of each group of samples were identified and compared.

RESULTS: Smooth muscle layers have been encountered within the walls of hernia sacs of both boys and girls. Although the hydrocele sacs have shown smooth muscle bundles distributed as patchy areas, smooth muscle bundles have been observed infrequently among sacs from patients with undescended testis. Peritoneum and processus vaginalis samples have been free of smooth muscle.

CONCLUSIONS: Inguinal hernia during childhood seems to be related to the presence of smooth muscle within the wall of the sac. The smooth muscle bundles may have played a role both in prevention of obliteration and clinical outcome. Because the sacs associated with undescended testis are without smooth muscles, and herniation is not a frequent association, they may not share the same etiologic basis with inguinal hernia.

GROSS APPEARANCE/
CLINICAL VARIANTS CHARACTERIZATION

GENERAL

DIRECT
More common in men and usually occur after the age of 40

Result from a weakness that develops in the groin area near the internal ring

INDIRECT
Most common type

Results from a weakness at the internal ring

In men may extend into the scrotum
In women may extend into the labia

FEMORAL More common in women

Results of a weakness below the groin

INCISIONAL May bulge through scars from previous surgical incisions and may develop months to years after the initial surgery

UMBILICAL HERNIA

OTHER VARIANTS

AMYAND'S HERNIA

Amyand's hernia: a case report of an incarcerated and perforated appendix within an inguinal hernia and review of the literature.

Logan MT, Nottingham JM.

Department of Surgery, The University of South Carolina School of Medicine, Columbia, USA.
Am Surg 2001 Jul;67(7):628-9 Abstract quote
Appendicitis within an Amyand's hernia is rare; when it occurs it is often misdiagnosed as a strangulated inguinal hernia.

We present a case report of such a case and a review of the literature.

It is our recommendation that repair should be undertaken without the use of synthetic mesh through a properitoneal incision that gives access to the peritoneal cavity and the inguinal regions.

INCARCERATION

Morbidity and mortality of inguinal hernia in the newborn.

Ameh EA.

Paediatric Surgery Unit, Department of Surgery, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria.
Niger Postgrad Med J 2002 Dec;9(4):233-4 Abstract quote
In an 11 year period, 17 newborns aged < or = 42 days had repair of 21 inguinal hernias. Eleven 52%) of the hernias were incarcerated or strangulated, necessitating bowel resection in 4 (36%) and orchidectomy for testicular infarction in 2 (18%). Only 4 babies with 7 hernias had elective herniotomy for uncomplicated hernia. In one baby with Hirschsprung's disease (bilateral hernia) and another with anorectal malformation, herniotomy was performed at the time of initial colostomy. Postoperatively, wound infection occurred in 4 (36%) of the 11 incarcerated or strangulated hernias (3 had bowel resection).

One baby who had intestinal resection died from overwhelming infection. The median hospital stay in babies with uncomplicated hernia was one day and 4 days in those with complicated hernia.

The morbidity of incarcerated and strangulated inguinal hernia in newborns is high, with attendant risk of bowel gangrene and testicular infarction. The principle of early referral and repair of inguinal hernias should be encouraged to avoid such morbidity and possible mortality.

SPIGELIAN HERNIA

Spigelian hernia.

Spangen L.

World J Surg 1989 Sep-Oct;13(5):573-80 Abstract quote
The diagnosis of spigelian hernia presents greater difficulties than its treatment. The clinical presentation varies, depending on the contents of the hernial sac and the degree and type of herniation. The pain, which is the most common symptom, varies and there is no typical pain of spigelian hernia.

Findings to facilitate diagnosis are palpable hernia and a palpable hernial orifice. Large, easily palpable spigelian hernias are not a diagnostic problem. It is small hernias and hernial orifices that are overlooked because they are masked by the subcutaneous fat and an intact external aponeurosis. In the absence of a palpable orifice or sac, persistent point tenderness in the spigelian aponeurosis with a tensed abdominal wall most strongly suggests the diagnosis. Spigelian hernia can be ruled out in patients without palpable tenderness. Ultrasonic scanning can be recommended for verification of the diagnosis in both palpable and nonpalpable spigelian hernia. The hernial orifice and sac can also be demonstrated by computed tomography, which gives more detailed information on the contents of the sac than does ultrasonic scanning.

The treatment of spigelian hernia is surgical, and the risk of recurrence is small. A gridiron incision is excellent for operations for palpable hernias. If the hernia cannot be palpated preoperatively, preperitoneal dissection through a vertical incision is recommended. This gives good exposure, facilitates hernioplasty, and permits preperitoneal exploration and treatment of other abdominal wall hernias. The incision is also suitable for exploratory laparotomy, which should be performed on patients with abnormal ultrasonographic or computed tomographic findings in whom no palpable hernia can be detected preoperatively.

HISTOLOGICAL TYPES CHARACTERIZATION

GENERAL

Routine pathological evaluation of tissue from inguinal hernias in children is unnecessary.

Miller GG, McDonald SE, Milbrandt K, Chibbar R.

Department of Surgery, University of Saskatchewan, Royal University Hospital, Saskatoon, Sask
Can J Surg 2003 Apr;46(2):117-9 Abstract quote
INTRODUCTION: Because unexpected disease is rare in a child's inguinal hernia sac we decided to investigate the cost of routine pathological evaluation of inguinal hernial sacs in children and the incidence of clinically significant pathological findings.

METHODS: We searched the health records at the University Hospital, Saskatoon, for patients under 20 years of age who had inguinal hernia repair between 1988 and 1997. For records noting pathology findings of duct-like structures, the operative reports and histology slides were reviewed. Specimens were immunostained for muscle-specific actin. The cost of pathological evaluation was estimated using a provincial physician-billing schedule.

RESULTS: During the study period, there were 488 inguinal hernia repairs in 371 patients under 20 years of age. Of these, 456 (93.4%) specimens were evaluated microscopically. There were 4 (0.88%) cases with unexpected findings diagnosed as epididymis at a cost of Can dollar 6988/case.

CONCLUSION: The routine histologic evaluation of inguinal hernia sacs in children is an unnecessary expense and should be reserved for select cases at the discretion of the surgeon.

Is routine pathological evaluation of pediatric hernia sacs justified?

Partrick DA, Bensard DD, Karrer FM, Ruyle SZ.

Department of Surgery, The Children's Hospital, University of Colorado Health Science Center, Denver 80218, USA.

J Pediatr Surg 1998 Jul;33(7):1090-2; discussion 1093-4 Abstract quote
BACKGROUND/PURPOSE: Herniorrhaphy is the most common general surgical procedure performed on children, and hernia sac material is one of the most common tissue specimens microscopically examined in the authors' surgical pathology laboratory. The risk of accidental vas deferens ligation has prompted the recommendation that all hernia sacs be examined pathologically. The authors hypothesized that the incidence of unrecognized vas deferens or epididymis ligation is actually very low and may not warrant routine pathological examination of all pediatric hernia sacs.

METHODS: Over a 3-year period (1994 to 1996), pathology reports from all hernia repairs at the authors' institution were reviewed. A total of 1,494 inguinal hernia sacs were pathologically evaluated from 1,077 pediatric patients (417 were bilateral). Pathological diagnoses not affecting clinical management (ie, chronic inflammation, irritated hernia sacs, embryonal remnants, adrenal cortical rests) were classified as incidental findings. Identification of true vas deferens was classified as a positive finding.

RESULTS: The study population had a mean age of 3.9 +/- 0.1 years and 963 (89%) were boys. The incidence of vas deferens injury from herniorrhaphy was found to be 0.13% (2 of 1,494), and these were recognized by the pediatric surgeon in the operating room.

CONCLUSIONS: When vas deferens injury is suspected, the sample should always be sent to the pathology department for confirmation. However, no occult carcinoma or other pathology was identified, and the remainder of the histological findings did not change the clinical treatment of any child. Given a fixed cost of pathological analysis, elimination of routine hernia sac examination may result in substantial annual savings. Therefore, in the current era of cost containment, recommendations for routine pathological examination of excised pediatric hernia sacs should be reevaluated.

The pathological evaluation of the pediatric inguinal hernia sac.

Wenner WJ Jr, Gutenberg M, Crombleholme T, Flickinger C, Bartlett SP.

Department of Pediatrics, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, 19104, USA.

J Pediatr Surg 1998 May;33(5):717-8 Abstract quote
BACKGROUND: The College of American Pathologists has suggested that institutions should establish guidelines for the evaluation of the hernia sac. In addition, some states require the submission of this tissue for pathological evaluation. Yet, neither evidence-based guidelines nor published reviews for the evaluation of the pediatric hernia sac are available. Therefore, this retrospective study was conducted to document experience with the evaluation of the pediatric hernia sac.

METHODS: All reports of the evaluation of hernia sacs submitted to the Department of Pathology during an 8-year period were reviewed. The case of any report that differed in any way from "consistent with hernia sac" was evaluated for the effect of the findings on the clinical course.

RESULTS: A total of 7,924 hernia sacs were submitted on 6,034 patients. Microscopic evaluation was performed on 534. A total of 7,567 (95.4%) submitted specimens on 5,743 patients were "consistent with hernia sac" and demonstrated no other findings. Three hundred fifty-seven specimens contained findings in addition to hernia sac. In no patient did the results of the evaluation have an effect on the patient care.

CONCLUSIONS: There is strong evidence that the routine pathological evaluation of pediatric hernia sacs offers little relevant clinical information. Mandatory tissue submission of hernia sacs should be reconsidered.

VARIANTS

EMBRYONAL REMNANTS

Embryonal remnants in inguinal hernia sacs.

Popek EJ.

Department of Pathology, Children's Hospital, Denver, CO.

Hum Pathol 1990 Mar;21(3):339-49 Abstract quote
Inguinal herniorrhaphy is the most common general surgical procedure performed on the neonate or young pediatric patient. The vas deferens and epididymis are vulnerable to damage, including transection during inguinal exploration or hernia repair. Occasionally the surgical pathologist encounters glandular or tubular epithelial-lined structures in hernia sac tissue. Significant medicolegal implications arise when embryonal remnants are mistakenly identified as true vas deferens or epididymis.

This study evaluates the incidence and morphology of these embryonal remnants in hernia sacs from patients of The Children's Hospital, Denver, CO. Embryonal remnants were found in 1.5% of 599 hernia sacs from 427 consecutively operated males aged 37 weeks gestation to 19 years. True vas deferens and epididymis were each identified once for an incidence of 0.33%. The remnants resemble either vas deferens or epididymis.

The average remnant diameter is 0.17 mm, and did not change significantly with age. Remnants are surrounded by varying amounts of condensed mesenchyme, trichrome-negative for muscle. The testes and vasa differentia from 32 autopsy cases, ranging in age from 26 weeks gestation to 7 years of age, were used to evaluate normal development and morphology of the vas deferens, epididymis and embryonal remnants. The vas deferens is well developed by 26 weeks gestation. The surrounding smooth-muscle coat does not stain with trichrome until 32 weeks gestation. The vas deferens increases in diameter in a linear fashion during gestation, and continues to increase in diameter in the postnatal period.

The vas deferens at 4 months of age is 1.2 to 1.4 mm in diameter; this is also the age of highest incidence of bilateral herniorrhaphies and presence of remnants.

GLANDULAR INCLUSIONS

Glandular inclusions in inguinal hernia sacs: morphologic and immunohistochemical distinction from epididymis and vas deferens.

Cerilli LA, Sotelo-Avila C, Mills SE.
Am J Surg Pathol 2003 Apr;27(4):469-76 Abstract quote
Glandular inclusions in inguinal hernia sacs may bear a striking resemblance to the epididymis or vas deferens. Misinterpretation as a transected functional structure may raise significant concerns regarding reproductive capability, even if encountered unilaterally. In a child, resolution of these concerns may be years away with the onset of puberty and documentation of normal sperm counts. CD10 has been shown to be present in Wolffian-type epithelium and to be absent in Mullerian-type epithelium.

We hypothesized that an antibody to CD10 would react with vas deferens and epididymis and fail to react with hernia sac inclusions, most of which we thought were Mullerian duct-derived structures. Glandular inclusions in 29 hernia sacs from prepubertal males were classified histologically according to their resemblance to normal structures and analyzed for CD10 by immunohistochemistry. Inclusions resembling vas deferens had their external diameters measured and were also stained for smooth muscle actin.

Thirty-one examples of normal vas deferens and 13 examples of normal epididymis were included for comparison. The inclusions were classified as vas deferens-like (9), epididymis-like (13), and Mullerian-like (7). CD10 reactivity was lacking in all vas deferens-like inclusions; their median external diameter was 0.6 mm. Of the epididymis-like inclusions, 7 of 13 were CD10 positive. The CD10-negative cases consisted of glands with well-defined stromal coats distinct from adjacent stromal coats. CD10-positive cases were more numerous, more tightly aggregated, and surrounded by less well-developed stromal coats that blended with adjacent coats. All seven Mullerian-like remnants were CD10 negative. All normal vas deferens and epididymis showed at least focal CD10 reactivity. CD10 positivity in all cases had a luminal membranous staining pattern.

Both the vas deferens-like inclusions and the normal vas deferens showed strong smooth muscle actin positivity in their stromal coats. CD10 negativity and external diameter <1 mm are highly useful to distinguish vas deferens-like inclusions from true vas deferens. Epididymis-like inclusions are more problematic. Some react for CD10 and may represent aberrant Wolffian ductules. Others are CD10 negative, distinct from true epididymis, and may be of Mullerian differentiation. Mullerian-like remnants can be diagnosed on the basis of their limited number and scattered distribution. Lack of CD10 immunostaining corroborates this interpretation.

Glandular inclusions in inguinal hernia sacs: a clinicopathological study of six cases.

Gomez-Roman JJ, Mayorga M, Mira C, Buelta L, Fernandez F, Val-Bernal JF.

Anatomical Pathology Department, Marques de Valdecilla University Hospital, Medical Faculty, University of Cantabria, Santander, Spain.
Pediatr Pathol 1994 Nov-Dec;14(6):1043-9 Abstract quote
Glandular inclusions in inguinal hernia sacs are not frequent. We present six cases of inguinal hernia with this finding, which represents an incidence of 2.6% in males and shows a predominance in the prepubertal stage.

Five patients showed cryptorchidism and two cases were related to congenital malformations of the single umbilical artery type and 47,XY chromosome disorder with chromosomal marker. The most important differential diagnosis must be made with normal histological structures such as the vas deferens or epididymis. The mean diameter of the inclusions was 0.1988 mm and there was a significant difference in size between the inclusions and the vas deferens, but not the epididymis. Differentiation from the latter is based on the absence of a well-developed muscular coat in the wall of the inclusions.

It is important to recognize that these inclusions can occur in hernia sacs because of the clinical and medicolegal implications that arise if they are confused with true epididymis or vas deferens. They may arise from paratesticular embryonal remnants.

MUCIN

Mucin deposits within inguinal hernia sacs: a presenting finding of low-grade mucinous cystic tumors of the appendix. A report of two cases and a review of the literature.

Young RH, Rosenberg AE, Clement PB.

Massachusetts General Hospital and the Department of Pathology, Harvard Medical School, Boston 02114-2696, USA.
Mod Pathol 1997 Dec;10(12):1228-32 Abstract quote
Two male patients, both 41 years of age, presented clinically with a typical inguinal hernia. The herniorrhaphy specimens were found on routine pathologic examination to contain abundant mucin that was focally organizing and was devoid of associated epithelial cells. Both cases were seen in consultation because of uncertainty as to the nature of the process.

The possibility that the mucin might represent spread from an appendiceal mucinous cystic tumor led to the investigation of the appendix and in both cases such a tumor was discovered. The widespread involvement of the peritoneum that is characteristic of pseudomyxoma peritonei was absent in each case.

These cases represent one of the many "surprise" findings that may be encountered in hernia sac specimens and one of the many problematic pathologic manifestations that may be associated with low-grade mucinous neoplasms of the appendix. Although this phenomenon is described in the literature, experience with our two cases indicates that it may still pose a significant diagnostic challenge.

SPERMATIC CORD

The incidence of spermatic cord structures in inguinal hernia sacs from male children.

Steigman CK, Sotelo-Avila C, Weber TR.

Department of Pathology, Cardinal Glennon Children's Hospital, St. Louis, Missouri 63104, USA.

Am J Surg Pathol 1999 Aug;23(8):880-5 Abstract quote
Inguinal herniorrhaphy is a common surgical procedure in children. Controversy exists regarding the usefulness of microscopic examination of hernia sacs, and changes in reimbursement schemes have heightened this controversy.

We summarize our experience with histologic examination of these specimens to establish benchmarks for the number of spermatic cord structures in inguinal hernia sacs from male children. A 14 1/2 consecutive calendar year review of pathology reports and histologic sections of hernia sacs was conducted at a tertiary care children's hospital. Of 7,314 males (range newborn to 19 years old), 65% had bilateral and 29% had unilateral herniorrhaphy (6% unknown). Seventeen cases contained vas deferens (0.23%); 22 had epididymis (0.30%); and 30 had embryonal rests (0.41%). Either vas deferens or epididymis was found in 0.53% of patients. No cases contained bilateral vas deferens, bilateral epididymis, or vas deferens in one side with epididymis in the contralateral side. Three hernia sacs contained co-existing vas deferens and epididymis. Our study helps to provide surgeons with information for preoperative counseling regarding potential injury to the vas deferens or epididymis.

This study provides baseline comparison data for quality improvement programs. We believe that each institution should weigh the costs, risks, and benefits of performing microscopic examinations on hernia sacs, depending on their own experience and data.

DIFFERENTIAL DIAGNOSIS KEY DIFFERENTIATING FEATURES

BUBO

Bubo masquerading as an incarcerated inguinal hernia.

Hodge KR, Orgler RJ, Monson T, Read RC.

Department of Surgery, University of Connecticut, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA
Hernia 2001 Jun;5(2):97-8 Abstract quote
A 44-year old, male, tattooed, leather jacket clad, Harley-Davidson motorcyclist arrived at the emergency room with a tender, irreducible mass, presenting at the external inguinal ring. In 1998, lung biopsy was read as miliary granuloma.

No herniation was found on urgent preperitoneal exploration. Incision of the mass showed acid-fast bacilli.

Culture later revealed Mycobacterium avium-intracellulare (MAI). A blood count showed CD4 lymphopenia; HIV was negative and remains so 2 years later.

LIPOSARCOMA

Liposarcoma of the spermatic cord masquerading as an incarcerated inguinal hernia.

Hassan JM, Quisling SV, Melvin WV, Sharp KW.

Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2765, USA.
Am Surg 2003 Feb;69(2):163-5 Abstract quote
We present a rare case of liposarcoma of the spermatic cord. There are only 61 reports in the literature. The presenting complaint is usually a painless bulge in the inguinal or scrotal region.

Our patient presented with a new-onset inguinoscrotal swelling that was misdiagnosed preoperatively as an incarcerated indirect hernia. The treatment for a spermatic cord liposarcoma is radical orchiectomy with high ligation of the cord.

Radiation therapy is recommended in addition to surgery in situations with evidence of tumor with propensity for more aggressive behavior (i.e., high-grade tumor, lymphatic invasion, inadequate margin, or recurrence). The current literature, diagnosis, and management of malignant tumors of the spermatic cord are reviewed.

PROGNOSIS CHARACTERIZATION

RECURRENCE

Recurrent hernia following endoscopic total extraperitoneal repair.

Chowbey PK, Bandyopadhyay SK, Sharma A, Khullar R, Soni V, Baijal M.

Department of Minimal Access Surgery, Sir Ganga Ram Hospital, New Delhi, India.

J Laparoendosc Adv Surg Tech A 2003 Feb;13(1):21-5 Abstract quote
BACKGROUND AND PURPOSE: A retrospective study was conducted to identify the reasons for recurrence following endoscopic total extraperitoneal (TEP) repair of inguinal hernias and to develop a strategy to prevent recurrence.

METHOD: Between January 1996 and December 2001, 1193 TEP hernia repairs were performed in 694 patients. Following reduction of the hernia sac and dissection of the preperitoneal space up to the psoas muscles laterally, a Prolene mesh (15 x 15 cm) was placed. The mesh was fixed medially to the Cooper ligament with two or three spiral tacks. In six patients, the hernia recurred following endoscopic TEP repair within the same period. Four of these patients elected to undergo laparoscopic transabdominal preperitoneal (TAPP) repair of the recurrent hernia.

RESULTS: Medial recurrences developed in three of the four patients because of medial displacement of the mesh. One patient was found to have a missed indirect hernia sac. All the patients who underwent laparoscopic TAPP repair had an uneventful recovery and are well at follow-up.

CONCLUSION: In addition to medial fixation of the mesh to the Cooper ligament, complete proximal dissection of the peritoneum from the spermatic cord and additional fixation of the mesh to the anterior abdominal wall, with careful avoidance of possible injury to the adjacent nerves, may prevent recurrences.

TREATMENT CHARACTERIZATION

GENERAL

Totally extraperitoneal endoscopic inguinal hernia repair (TEP).

Tamme C, Scheidbach H, Hampe C, Schneider C, Kockerling F.

Department of Surgery and Center for Minimally Invasive Surgery, Hanover Hospital, Roesebeckstrasse 15 (Siloah), 30449 Hanover, Germany.

Surg Endosc 2003 Feb;17(2):190-5 Abstract quote
Background: This report reviews our experience with 5,203 totally extraperitoneal (TEP) endoscopic hernia repairs performed in 3,868 patients over the 7.5-year period between May 1994 and December 2001, 34.5% of whom had bilateral hernias and 13% recurrent hernias.

Methods: We performed TEP as the method of choice in more than 92% of all the patients presenting with inguinal hernia, including those with incarcerated, strangulated, or inguinoscrotal hernias. After reduction of the hernial sac and appropriate dissection of the preperitoneal space, we placed a slit-free 10 x 15-cm polypropylene mesh without the use of staple fixation.

Results: Altogether, 29 recurrent hernias (0.6%) were observed, more than 50% of which occurred during the first 2 years after the technique was introduced (1.8%). During subsequent years, the recurrence rate settled to approximately 0.3%. Regarding intraoperative complications, we observed eight injuries to the bladder. At this writing, no bowel injuries or damage to iliac vessels has been seen. Postoperatively, we noted only a single case of mesh infection. In 14 cases (0.4%), postoperative hemorrhage necessitated either inguinal or endoscopic reoperation. As a further major complication, a small bowel obstruction caused by inadequate closure of a peritoneal lesion occurred in two patients (0.05%). The overall reoperation rate for the 3,868 patients was 0.6%.

Conclusions: We consider TEP to be a procedure that carries an acceptably low complication rate, combining the advantages of minor access surgery and mesh reinforcement of the groin. This approach is associated with early postoperative return to usual activities and a very low recurrence rate.

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Last Updated 4/16/2003

PATHOGENESIS	CHARACTERIZATION
CALCIUM
Total calcium content of sacs associated with inguinal hernia, hydrocele or undescended testis reflects differences dictated by programmed cell death. Tanyel FC, Ulusu NN, Tezcan EF, Buyukpamukcu N. Department of Pediatric Surgery, Hacettepe University, Faculty of Medicine, Ankara, Turkey.	Urol Int 2003;70(3):211-5 Abstract quote INTRODUCTION: Inguinal hernia and hydrocele are suggested to result from the persistence of smooth muscle (SM) which should undergo programmed cell death (PCD) after presenting transiently to propel the testis. Since Ca(2+) is involved in PCD, the Ca(2+) contents of the peritoneum and sacs associated with undescended testis, inguinal hernia and hydrocele were determined and compared. MATERIALS AND METHODS: Sacs were obtained from boys with undescended testis (n = 11), inguinal hernia (n = 22) and hydrocele (n = 10), and girls with inguinal hernia (n = 7). The calcium content of the sacs and peritoneal samples (n = 6) was determined through atomic absorption spectrophotometry. Calcium contents were compared according to their sources using the Mann-Whitney U test and p values of <0.05 were considered significant. RESULTS: While revealing similar Ca(2+) contents as the peritoneum, sacs associated with undescended testis and hydrocele contained more Ca(2+) contents than the sacs of boys and girls with inguinal hernia (p < 0.05). CONCLUSIONS: Sacs associated with inguinal hernia, which are known to contain SM all around the mesothelial layer, contain the least Ca(2+). Despite the decrease in SM, sacs associated with hydrocele contain more Ca(2+). Since PCD is associated with Ca(2+) overload and inhibition of Ca(2+) load inhibits PCD, differences in Ca(2+) content may reflect the inhibition of PCD at different stages and for different reasons in inguinal hernia or hydrocele of childhood.
COLLAGEN SYNTHESIS
Synthesis of type I and III collagen, expression of fibronectin and matrix metalloproteinases-1 and -13 in hernial sac of patients with inguinal hernia. Klinge U, Zheng H, Si ZY, Schumpelick V, Bhardwaj R, Klosterhalfen B. The Department of Surgery, The Technical University of Aachen, Germany.	Int J Surg Investig 1999;1(3):219-27 Abstract quote Since many years the importance of a weakness of the soft tissue for the development of hernias is discussed controversially. The tensile strength of the tissue is supposed to depend largely on the varying proportion of type I collagen with its high tensile strength and the immature type III collagen. Their relation is regulated by several collagenases, mainly matrix metalloproteinases-1 and -13 (MMP-1 and MMP-13), whereas fibronectin plays a key role for the adherence of cells within the extracellular matrix. The aim of this study was to investigate whether an alteration in type I and type III collagen synthesis, amounts of MMP-1 and MMP-13 and the expression of fibronectin were associated with the development of inguinal hernia. We analysed the hernial sac of patients with indirect (n = 9) and direct (n = 7) inguinal hernias and peritoneum in controls (n = 7) by immunohistochemistry and Western blot analysis. The results showed that the ratio of relative amount of I/III collagen was markedly decreased in patients with either indirect or direct hernias as compared with controls (p < 0.001) with a concomitant increase in type III collagen synthesis. MMP-13 was expressed neither in the hernial sac nor in the peritoneum of the controls, but the positive reactions of MMP-1 were found in the surface of the subserosa of the hernial sac in patients with indirect or direct hernias without any difference compared to controls. Furthermore, the relative amount of fibronectin in patients with either indirect or direct hernias is not significantly different from controls (p > 0.05). In regard to the known alterations of the collagen metabolism in fascia and skin of hernia patients the changed collagen I/III ratio with its increase of type III collagen in hernial sacs support the presence of a systemic disturbance of collagen metabolism. The absence of changes of the expression of collagenases (MMP-1, MMP-13) and the constant levels of fibronectin underline the central role of collagen synthesis for the development of indirect or direct hernias.
MYOFIBROBLASTS
Myofibroblasts defined by electron microscopy suggest the dedifferentiation of smooth muscle within the sac walls associated with congenital inguinal hernia. Tanyel FC, Muftuoglu S, Dagdeviren A, Kaymaz FF, Buyukpamukcu N. Department of Paediatric Surgery, University, Faculty of Medicine, Ankara, Turkey.	BJU Int 2001 Feb;87(3):251-5 Abstract quote OBJECTIVE: To ascertain the presence of myofibroblasts in sacs associated with inguinal hernia in children, through an ultrastructural evaluation using electron microscopy. MATERIALS AND METHODS: Sacs were obtained from 10 boys and 10 girls (of similar age, approximately 45 months) with inguinal hernia and processed for electron microscopy. Thin sections were examined specifically for the presence of myofibroblasts. RESULTS: The ultrastructural evaluation showed myofibroblasts with classical electron microscopic features within all of the sacs, regardless of the gender of origin. CONCLUSION: The persistence of smooth muscle hinders the obliteration of the processus vaginalis; myofibroblasts are found in association with smooth muscle and thus such cells within the sac walls seem to originate from the smooth muscle, reflecting the dedifferentiation of smooth muscle. This dedifferentiated state may represent attempted apoptosis, which usually causes the disappearance of the smooth muscle and obliteration of the processus vaginalis after the descent of the testis into the scrotum.
SMOOTH MUSCLE
Inguinal hernia revisited through comparative evaluation of peritoneum, processus vaginalis, and sacs obtained from children with hernia, hydrocele, and undescended testis. Tanyel FC, Dagdeviren A, Muftuoglu S, Gursoy MH, Yuruker S, Buyukpamukcu N. Department of Pediatric Surgery, Hacettepe University, Faculty of Medicine, Ankara, Turkey.	J Pediatr Surg 1999 Apr;34(4):552-5 Abstract quote BACKGROUND/PURPOSE: Histological structures of peritoneum, processus vaginalis, and sacs obtained from girls with inguinal hernia and boys with inguinal hernia, hydrocele, and undescended testis have been compared through immunohistochemical features to evaluate if any clue descriptive for the etiology of inguinal hernia exists. METHODS: Parietal peritoneums (n = 6), processus vaginalises (n = 4), female hernia sacs (n = 5), male hernia sacs (n 12), and sacs from hydrocele (n = 5) and undescended testis (n = 9) were stained with indirect immunoperoxidase method. Anti-CD9, CD26, CD29, CD31, CD36, CD44, CD49a, CD49b, CD49c, CD49d, CD49e, CD49f, CD54, CD55, CD56, CD62E & P, CD71, CD98, CD102, CD106, CD146, CD151 monoclonals and NFL-NPH, S-100 antiserums were used. The histological structures of each group of samples were identified and compared. RESULTS: Smooth muscle layers have been encountered within the walls of hernia sacs of both boys and girls. Although the hydrocele sacs have shown smooth muscle bundles distributed as patchy areas, smooth muscle bundles have been observed infrequently among sacs from patients with undescended testis. Peritoneum and processus vaginalis samples have been free of smooth muscle. CONCLUSIONS: Inguinal hernia during childhood seems to be related to the presence of smooth muscle within the wall of the sac. The smooth muscle bundles may have played a role both in prevention of obliteration and clinical outcome. Because the sacs associated with undescended testis are without smooth muscles, and herniation is not a frequent association, they may not share the same etiologic basis with inguinal hernia.

Epidemiology
Pathogenesis
Gross Appearance and Clinical Variants
Histopathological Features and Variants
Differential Diagnosis
Prognosis
Treatment
Commonly Used Terms
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EPIDEMIOLOGY	CHARACTERIZATION
INCIDENCE/PREVALENCE	See Clinical Variants
AGE	See Clinical Variants
SEX	See Clinical Variants

GROSS APPEARANCE/ CLINICAL VARIANTS	CHARACTERIZATION
GENERAL
DIRECT	More common in men and usually occur after the age of 40 Result from a weakness that develops in the groin area near the internal ring
INDIRECT	Most common type Results from a weakness at the internal ring In men may extend into the scrotum In women may extend into the labia
FEMORAL	More common in women Results of a weakness below the groin
INCISIONAL	May bulge through scars from previous surgical incisions and may develop months to years after the initial surgery
UMBILICAL HERNIA
OTHER VARIANTS
AMYAND'S HERNIA
Amyand's hernia: a case report of an incarcerated and perforated appendix within an inguinal hernia and review of the literature. Logan MT, Nottingham JM. Department of Surgery, The University of South Carolina School of Medicine, Columbia, USA.	Am Surg 2001 Jul;67(7):628-9 Abstract quote Appendicitis within an Amyand's hernia is rare; when it occurs it is often misdiagnosed as a strangulated inguinal hernia. We present a case report of such a case and a review of the literature. It is our recommendation that repair should be undertaken without the use of synthetic mesh through a properitoneal incision that gives access to the peritoneal cavity and the inguinal regions.
INCARCERATION
Morbidity and mortality of inguinal hernia in the newborn. Ameh EA. Paediatric Surgery Unit, Department of Surgery, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria.	Niger Postgrad Med J 2002 Dec;9(4):233-4 Abstract quote In an 11 year period, 17 newborns aged < or = 42 days had repair of 21 inguinal hernias. Eleven 52%) of the hernias were incarcerated or strangulated, necessitating bowel resection in 4 (36%) and orchidectomy for testicular infarction in 2 (18%). Only 4 babies with 7 hernias had elective herniotomy for uncomplicated hernia. In one baby with Hirschsprung's disease (bilateral hernia) and another with anorectal malformation, herniotomy was performed at the time of initial colostomy. Postoperatively, wound infection occurred in 4 (36%) of the 11 incarcerated or strangulated hernias (3 had bowel resection). One baby who had intestinal resection died from overwhelming infection. The median hospital stay in babies with uncomplicated hernia was one day and 4 days in those with complicated hernia. The morbidity of incarcerated and strangulated inguinal hernia in newborns is high, with attendant risk of bowel gangrene and testicular infarction. The principle of early referral and repair of inguinal hernias should be encouraged to avoid such morbidity and possible mortality.
SPIGELIAN HERNIA
Spigelian hernia. Spangen L.	World J Surg 1989 Sep-Oct;13(5):573-80 Abstract quote The diagnosis of spigelian hernia presents greater difficulties than its treatment. The clinical presentation varies, depending on the contents of the hernial sac and the degree and type of herniation. The pain, which is the most common symptom, varies and there is no typical pain of spigelian hernia. Findings to facilitate diagnosis are palpable hernia and a palpable hernial orifice. Large, easily palpable spigelian hernias are not a diagnostic problem. It is small hernias and hernial orifices that are overlooked because they are masked by the subcutaneous fat and an intact external aponeurosis. In the absence of a palpable orifice or sac, persistent point tenderness in the spigelian aponeurosis with a tensed abdominal wall most strongly suggests the diagnosis. Spigelian hernia can be ruled out in patients without palpable tenderness. Ultrasonic scanning can be recommended for verification of the diagnosis in both palpable and nonpalpable spigelian hernia. The hernial orifice and sac can also be demonstrated by computed tomography, which gives more detailed information on the contents of the sac than does ultrasonic scanning. The treatment of spigelian hernia is surgical, and the risk of recurrence is small. A gridiron incision is excellent for operations for palpable hernias. If the hernia cannot be palpated preoperatively, preperitoneal dissection through a vertical incision is recommended. This gives good exposure, facilitates hernioplasty, and permits preperitoneal exploration and treatment of other abdominal wall hernias. The incision is also suitable for exploratory laparotomy, which should be performed on patients with abnormal ultrasonographic or computed tomographic findings in whom no palpable hernia can be detected preoperatively.

DIFFERENTIAL DIAGNOSIS	KEY DIFFERENTIATING FEATURES
BUBO
Bubo masquerading as an incarcerated inguinal hernia. Hodge KR, Orgler RJ, Monson T, Read RC. Department of Surgery, University of Connecticut, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA	Hernia 2001 Jun;5(2):97-8 Abstract quote A 44-year old, male, tattooed, leather jacket clad, Harley-Davidson motorcyclist arrived at the emergency room with a tender, irreducible mass, presenting at the external inguinal ring. In 1998, lung biopsy was read as miliary granuloma. No herniation was found on urgent preperitoneal exploration. Incision of the mass showed acid-fast bacilli. Culture later revealed Mycobacterium avium-intracellulare (MAI). A blood count showed CD4 lymphopenia; HIV was negative and remains so 2 years later.
LIPOSARCOMA
Liposarcoma of the spermatic cord masquerading as an incarcerated inguinal hernia. Hassan JM, Quisling SV, Melvin WV, Sharp KW. Department of Urology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2765, USA.	Am Surg 2003 Feb;69(2):163-5 Abstract quote We present a rare case of liposarcoma of the spermatic cord. There are only 61 reports in the literature. The presenting complaint is usually a painless bulge in the inguinal or scrotal region. Our patient presented with a new-onset inguinoscrotal swelling that was misdiagnosed preoperatively as an incarcerated indirect hernia. The treatment for a spermatic cord liposarcoma is radical orchiectomy with high ligation of the cord. Radiation therapy is recommended in addition to surgery in situations with evidence of tumor with propensity for more aggressive behavior (i.e., high-grade tumor, lymphatic invasion, inadequate margin, or recurrence). The current literature, diagnosis, and management of malignant tumors of the spermatic cord are reviewed.