Femoral hernias are more likely to strangulate than inguinal ones, and are much less common. They are rare in India and Africa and in children everywhere. Whereas inguinal hernias are almost entirely a male disease, the sex incidence of femoral hernias is more nearly equal, with femoral hernias only marginally more common in men than in women in most communities.
A patient with a femoral hernia complains of a painful spherical 3 cm mass in the subcutaneous tissues of his or her upper thigh. Sometimes, a femoral hernia turns upwards, and may come to lie over the inguinal ligament, where you can mistake it for an inguinal one, or it can turn outwards or downwards. Repair is not difficult, and recurrence is rare. So always operate; a truss cannot control a femoral hernia. There are several ways of approaching a femoral hernia: use the low one described here, unless you need to resect gut.
ANATOMY. A femoral hernia comes through the femoral canal. This is about 2 cm long and is filled with fat and a lymph node (Cloquet's). Anteriorly, it is bounded by the inguinal ligament, and posteriorly by the pectineal ligament (Cooper's ligament) which is a thickened part of the pectineal fascia, and overlies the pectineal ridge of the pubic bone. The femoral vein lies [f10]laterally, [f09]and the sharp edge of the lacunar ligament lies medially. A femoral hernia extends forwards through the fossa ovalis where the long saphenous vein joins the femoral vein. Fig. 14-16 REPAIRING A FEMORAL HERNIA. A, the external inguinal ring exposed. B, the sac mobilized. C, the inguinal ligament being stitched to the pectineal ligament (Cooper's ligament).
FEMORAL HERNIA [s8]UNSTRANGULATED DIAGNOSIS. The patient has a tense, slightly tender, spherical mass below his inguinal ligament, 2 cm inferolateral to his pubic tubercle. Usually, you cannot reduce it. If you can reduce it, you may be able to pass your finger upwards through his dilated femoral canal. There is usually no cough impulse.
THE DIFFERENTIAL DIAGNOSIS given here applies to unstrangulated femoral hernias, and to strangulated ones.
Suggesting an indirect inguinal hernia[md]an elongated swelling arising above the inguinal ligament, and perhaps extending to his scrotum.
Suggesting a direct inguinal hernia[md]a bulge above his inguinal ligament, which is usually easily reducible, and has a cough impulse.
Suggesting enlarged lymph nodes, from either a pyogenic infection, or tuberculosis[md]perhaps a septic focus on his leg, his lower abdomen, or his buttock. Evidence of tuberculosis elsewhere. An enlarged deep inguinal lymph node may be almost impossible to distinguish from a femoral hernia. If you have difficulty distinguishing between a hernia and lymphadenitis, put him to bed, give him antibiotics and see if the mass becomes smaller. Or make a careful incision over the mass, and see if you can get underneath it. If you think it might be a strangulated hernia, operate without delay.
Suggesting a varix of his long saphenous vein[md]a soft, easily compressible swelling (unless it is thrombosed), which fills up again when you release the pressure.
Other rare differential diagnoses incude: an inflamed appendix in a hernial sac, an obturator hernia, and a tense painful pointing psoas abscess (much larger).
ANAESTHESIA. (1) Local infiltration, especially if his general condition is poor. Use the same method as for an inguinal hernia (A 6.12). Infiltrate a wide subcutaneous area, and infiltrate the neck of the sac as you dissect deeper. (2) Subarachnoid or epidural anaesthesia (A 7.6). (3) General anaesthesia with relaxants.
INCISION. Make a 6 cm incision directly over the hernia below his groin crease. Deepen the wound through his subcutaneous tissue to expose the sac (A, in Fig. 14-16). Tie the tributaries of his long saphenous vein.
Use blunt dissection to mobilize the sac free from the tissues around it (B). Trace it to its neck, where it disappears into his femoral canal.
Carefully incise the fundus of the sac. Cut through fat until you find the much smaller peritoneal sac. Expect to cut through many layers. Inspect its contents. This will usually be omentum, except in long-standing hernias. Reduce the contents completely, and divide any adhesions.
When the sac and its contents are cleanly exposed, and you are quite sure that you have completely reduced its contents, twist it. Transfix its neck with thread as high up as you can, and excise it, leaving a generous neck distal to the transfixing suture. The stump will disappear up into his femoral canal.
Then insert a few monofilament stitches, so as to approximate his inguinal ligament to the thickened part of his pectineal fascia, on the floor of his femoral canal. This is his pectineal ligament (Cooper's ligament) (C). Protect his femoral vein laterally with your finger, while you are inserting these stitches. Close his skin unless his hernia was strangulated.
DIFFICULTIES [s7]WITH A FEMORAL HERNIA If you injure his femoral vein see 14.3. See also the ''difficulties' in Section 14.8.
If you CANNOT RETURN THE CONTENTS OF THE SAC easily pass your finger gently upwards outside it and dilate his femoral ring. If this fails, stretch the ring by putting a haemostat into it and opening it. Or, carefully enlarge the superomedial side of his femoral canal, but be careful of an abnormal obturator artery, (A, 14-18, also see below).
If you CANNOT GET GOOD BITES OF HIS PECTINEAL LIGAMENT as it lies on his pectineal fascia, get a short curved needle, or a fish-hook needle, and set it in a needleholder in such a way that it points back at you. Insert this into his femoral canal, and try to hook the ligament on your way out.
If there is ARTERIAL BLEEDING as you enlarge his femoral canal, you have injured his abnormal obturator artery. Normally, the obturator artery arises from the anterior trunk of the internal iliac artery. In about 25% of people the pubic branch of the inferior epigastric artery takes its place. This abnormal obturator artery may occasionally pass over the internal aspect of the femoral canal, or run in the edge of the lacunar ligament[md]where you can easily cut it (A, 14-18).
If so, open up his inguinal canal, open up its posterior wall between his inguinal ligament inferiorly and his conjoined tendon superiorly. This will expose his peritoneum. Push this up and you will find his abnormal obturator artery crossing the internal aspect of his femoral canal. Grasp it with a haemostat and tie it.
Fig. 14-17 INGUINAL AND FEMORAL HERNIAS. A, a complete indirect inguinal hernia reaching right down into the patient's scrotum. B, an incomplete indirect hernia in which the processus vaginalis ends just above his testis. C, a femoral hernia, showing how the sac extends upwards. D, a small indirect inguinal hernia showing the sac extending downwards. E, bilateral direct inguinal hernias. After Bailey and Love.