出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/03/27 15:02:09」(JST)
| Inguinal hernia | |
|---|---|
| Classification and external resources | |
Diagram of an indirect, scrotal inguinal hernia (median view from the left). |
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| ICD-10 | K40 |
| ICD-9 | 550 |
| DiseasesDB | 6806 |
| MedlinePlus | 000960 |
| eMedicine | med/2703 emerg/251 ped/2559 |
| MeSH | C06.405.293.249.437 |
An inguinal hernia (pron.: /ˈɪŋɡwɨnəl ˈhɜrniə/) is a protrusion of abdominal-cavity contents through the inguinal canal. They are very common (lifetime risk 27% for men, 3% for women[1]). Though their repair is one of the most frequently performed surgical operations, elective surgery is no longer recommended in minimally symptomatic cases, due to the low risk of incarceration (<0.2% per year) and the significant risk (10–12%) of post herniorraphy pain syndrome.[2][3]
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There are two types of inguinal hernia, direct and indirect, which are defined by their relationship to the inferior epigastric vessels. Direct inguinal hernias occur medial to the inferior epigastric vessels when abdominal contents herniate through a weak spot in the fascia of the posterior wall of the inguinal canal, which is formed by the transversalis fascia. Indirect inguinal hernias occur when abdominal contents protrude through the deep inguinal ring, lateral to the inferior epigastric vessels; this may be caused by failure of embryonic closure of the processus vaginalis.
In the case of the female, the opening of the superficial inguinal ring is smaller than that of the male. As a result, the possibility for hernias through the inguinal canal in males is much greater because they have a larger opening and therefore a much weaker wall through which the intestines may protrude.
| Type | Description | Relationship to inferior epigastric vessels | Covered by internal spermatic fascia? | Usual onset |
|---|---|---|---|---|
| indirect inguinal hernia | protrudes through the inguinal ring and is ultimately the result of the failure of embryonic closure of the internal inguinal ring after the testicle passes through it | Lateral | Yes | Congenital |
| direct inguinal hernia | enters through a weak point in the fascia of the abdominal wall (Hesselbach triangle) | Medial | No | Adult |
Inguinal hernias, in turn, belong to groin hernias, which also includes femoral hernias. A femoral hernia is not via the inguinal canal, but via the femoral canal, which normally allows passage of the common femoral artery and vein from the pelvis to the leg.
In Amyand's hernia, the content of the hernial sac is the vermiform appendix.
In Littre's hernia, the content of the hernial sac contains a Meckel's Diverticulum.
Clinical classification of hernia is also important according to which hernia is classified into
Reducible hernia: is one which can be pushed back into the abdomen by putting manual pressure to it.
Irreducible hernia: is one which cannot be pushed back into the abdomen by applying manual pressure.
Irreducible hernias are further classified into
Obstructed hernia-is one in which the lumen of the herniated part of intestine is obstructed but the blood supply to the hernial sac is intact.
Incarcerated hernia-is one in which adhesions develop between the wall of hernial sac and the wall of intestine.
Strangulated hernia- is one in which the blood supply of the sac is cut off, thus, leading to ischemia. the lumen of the intestine may be patent or not.
Hernias present as bulges in the groin area that can become more prominent when coughing, straining, or standing up. They are rarely painful, and the bulge commonly disappears on lying down. The inability to "reduce", or place the bulge back into the abdomen usually means the hernia is 'incarcerated' which requires emergency surgery.
Significant pain is suggestive of strangulated bowel (an incarcerated indirect inguinal hernia).
As the hernia progresses, contents of the abdominal cavity, such as the intestines, can descend into the hernia and run the risk of being pinched within the hernia, causing an intestinal obstruction. If the blood supply of the portion of the intestine caught in the hernia is compromised, the hernia is deemed "strangulated" and gut ischemia and gangrene can result, with potentially fatal consequences. The timing of complications is not predictable. Emergency surgery for incarceration and strangulation carry much higher risk than planned, "elective" procedures. However, the risk of incarceration is low, evaluated at 0.2% per year.[2] On the other hand, surgical intervention has a significant risk of causing inguinodynia, and this is why minimally symptomatic patients are advised to watchful waiting.
Differential diagnosis of the symptoms of inguinal hernia mainly includes the following potential conditions:[4]
In men, indirect hernias follow the same route as the descending testes, which migrate from the abdomen into the scrotum during the development of the urinary and reproductive organs. The larger size of their inguinal canal, which transmitted the testicle and accommodates the structures of the spermatic cord, might be one reason why men are 25 times more likely to have an inguinal hernia than women. Although several mechanisms such as strength of the posterior wall of the inguinal canal and shutter mechanisms compensating for raised intra-abdominal pressure prevent hernia formation in normal individuals, the exact importance of each factor is still under debate. The physiological school of thought thinks that the risk of hernia is due to a physiological difference between patients who suffer hernia and those who do not, namely the presence of aponeurotic extensions from the transversus abdominis aponeurotic arch.[5]
There is currently no medical recommendation about how to manage an inguinal hernia condition, due to the fact that until recently,[6][7] elective surgery used to be recommended. However, people with inguinal hernias sometimes use some practices. The hernia truss is intended to contain a reducible inguinal hernia within the abdomen. It is not considered to provide a cure, and if the pads are hard and intrude into the hernia aperture they may cause scarring and enlargement of the aperture. In addition, most trusses with older designs are not able effectively to contain the hernia at all times, because their pads do not remain permanently in contact with the hernia. The more modern variety of truss is made with non-intrusive flat pads and comes with a guarantee to hold the hernia securely during all activities. Although there is as yet no proof that such devices can prevent an inguinal hernia from progressing, they have been described by users as providing greater confidence and comfort when carrying out physically demanding tasks[citation needed]. A truss also increases the probability of complications,which include strangulation of the hernia, atrophy of the spermatic cord, and atrophy of the fascial margins.This allows the defect to enlarge and makes subsequent repair more difficult.[8] Their popularity is likely to increase, as many individuals with small, painless hernias are now delaying hernia surgery due to the risk of post-herniorrhaphy pain syndrome.[9] The elasticised pants used by athletes also provide useful support for the smaller hernia.
Surgical correction of inguinal hernias is called a hernia repair. It is currently not recommended in minimally symptomatic hernias, for which watchful waiting is advised, due to the risk of post herniorraphy pain syndrome. Surgery is commonly performed as outpatient surgery. There are various surgical strategies which may be considered in the planning of inguinal hernia repair. These include the consideration of mesh use (e.g. synthetic or biologic), open repair, use of laparoscopy, type of anesthesia (general or local), appropriateness of bilateral repair, etc. During surgery conducted under local anaesthesia, the patient will be asked to cough and strain during the procedure to help in demonstrating that the repair is without tension and sound.[10] Constipation after hernia repair results in strain to evacuate the bowel causing pain, and fear that the sutures may rupture. Opioid analgesia makes constipation worse. Promoting an easy bowel motion is important post-operatively.
A direct inguinal hernia is less common (~25–30% of inguinal hernias) and usually occurs in men over 40 years of age.
Different types of inguinal hernias.
Inguinal fossae
Old & new hernia scars 2009
Bilateral Hernia scars 7 days after surgery
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| リンク元 | 「鼡径ヘルニア」 |
| 関連記事 | 「inguinal」 |