Strangulated femoral hernias

A strangulated femoral hernia causes more mistakes in diagnosis than a strangulated inguinal one: (1) It may be small, and lost in the thick fat of a patient's groin. (2) Only the circumference of his gut may be caught (Richter's hernia), so that you can hardly feel anything in his thigh. (3) When it is large, it may have a rounded fundus and a narrow neck, which allows the fundal part to move painlessly, so you may think there is no strangulation. This makes it very important to explore any doubtful lump in the femoral region, when a patient has abdominal symptoms, especially if femoral hernias are not uncommon in your area.

The femoral canal is so small that you cannot easily bring gut out through it for resection and anastomosis. Explore the canal from below, and if you have to resect and anastomose gut, do this through a lower abdominal incision, either a lower midline, or a Pfannensteil incision.

There are two approaches to a strangulated femoral hernia, with some doubt as to which is best: (1) the standard approach, which requires two incisions, one over the hernia and another in the lower abdomen, and (2) the Lotheissen approach through a single incision in the posterior wall of the inguinal canal.

In the standard approach, cut down over the patient's inguinal ligament and aim to: (1) Expose and isolate the sac. (2) Open and inspect its contents. If his gut is viable, you can do the whole operation from below. (3) If it is not viable, open his abdomen through a lower midline or Pfannensteil incision. Expose and if necessary enlarge his femoral ring from above. (4) Return the contents to his abdomen through the ring. (5) Resect gut if necessary. (5) Excise the sac and repair the wound.

If you have difficulty reducing the sac: (1) You can incise the lacunar ligament on the medial side of the sac. The danger in doing this is that abnormal obturator vessels may pass close to its lateral (or medial) sides, and be cut by mistake (14-18). (2) You can divide and then repair his inguinal ligament. The danger with this is that, if his wound becomes infected, a hernia may form later which will be difficult to repair. Whatever you do, remember that the femoral vein lies on the lateral side of his femoral canal!

IF THERE ARE ABDOMINAL SYMPTOMS, EXPLORE ANY TENDER FEMORAL LUMP Fig. 14-18 A STRANGULATED FEMORAL HERNIA. A, the anatomy of the femoral canal. Note that the femoral vein lies laterally and the lacunar ligament (reflected part of the inguinal ligament) lies medially. An abnormal obturator artery may run in the edge of this ligament. B, a guarded bistoury can be used to open up the femoral canal on its medial side. In view of the risk of cutting an abnormal obturator artery, this is best used only in inguinal hernias. C, a side view of the femoral canal showing how a femoral hernia forms. D, a strangulated femoral hernia opened from below. Most femoral hernias are smaller than this. The inguinal ligament has been divided[md]this is very rarely necessary. D, adapted from a drawing by Frank Netter, with the kind permission of CIBA-GEIGY Ltd, Basle (Switzerland).

STRANGULATED FEMORAL HERNIA For the general method for intestinal obstruction, see Section 10.3.

DIFFERENTIAL DIAGNOSIS. See Sections 14.2 and 14.7. You can easily overlook a strangulated femoral hernia in a fat patient.

ANAESTHESIA. (1) Local anaesthesia is particularly suitable if the patient is old or sick (A 6.12). (2) Ketamine (A 8.1). If you are using local anaesthesia, infiltrate the field widely as in A 5.4. Inject more solution into the deeper tissues as you get to them. (3) Subarachnoid or epidural anaesthesia if the patient is fairly fit. (4) General anaesthesia and tracheal intubation with relaxants.

PREPARATION. Pass a catheter and empty his bladder.

STANDARD APPROACH INCISION. Make a transverse incision in the skin crease over the hernia itself. Divide the covering layers, including his deep fascia, and dissect them off the sac. Sweep your finger round the hernia to mobilize it, and define its neck. Clean it by dissection with your finger, and a swab and not-too- sharp-nosed scissors.

TO OPEN THE SAC insert retractors and pack off the sac while you carefully cut down on it. Like an onion, it will have more layers than you expect. As soon as you are inside it, there will be a warning spurt of turbid blood-stained fluid. If his gut is gangrenous, this will be faeculent.

TO RELEASE THE STRANGULATION hold his gut in a swab between the finger and thumb of one hand. Meanwhile, try to widen his femoral canal by inserting the very tip of your finger into his hernia, just outside the sac itself. With your finger inside his femoral canal, move it around the neck of the sac and try to free it.

CAUTION ! Don't let go of his gut at this point. You may find that you have to do a laparotomy to retrieve it.

Now draw the gut down into the sac a bit more. If it does not quite come, repeat the dilating manoeuvre, but this time with your finger inside the sac, between it and his gut.

If you still cannot deliver his gut into the wound, clear the neck of fatty tissue. Enlarge the ring on its medial side by dividing his lacunar ligament, and the fibrous tissue in front of the ring. Protect the contents of the sac while you divide the ligament by passing a grooved director up the medial side of its neck. Then carefully cut down on the director with one or two nicks of a scalpel. Or, use a guarded bistoury. Watch out for an abnormal obturator artery.

With his gut drawn down into the sac, wrap it in a warm wet swab, to see if it is viable (9-8).

If it is viable, let it slip back into his abdominal cavity, and repair his hernia from below.

If it is not viable, do a lower midline (or Pfannensteil) incision, and resect and anastomose his gut from above.

If his omentum looks as if it might not be viable, transfix it, tie it, and excise it.

If an area of necrosis only involves part of the wall of his gut (Richter's hernia), bury it with invaginating seromuscular catgut sutures, as in Fig. 14-1. You need not resect it, provided it follows the criteria for safe invagination. These are described for a Busoga hernia near the end of Section 14.2 and in Section 9.3.

If you are in any doubt about the viability of his gut, (including a Richter's hernia), excise the damaged portion and do an end-to-end anastomosis (9-9).

CAUTION ! (1) Always open the sac and inspect its contents before you return them to his abdomen. They may be gangrenous. If he has a Richter's hernia, be especially careful not to let it escape back into his abdomen. (2) Take great care not to contaminate his peritoneal cavity.

REPAIR. If you have opened his abdomen, you can repair his hernia from above or below, as you wish. You may find it convenient to repair it from below and to add a few stitches from above, if necessary. Transfix, tie, and excise the sac, as in Section 14.7.

CAUTION ! Take care to clean it free of surrounding tissues before you excise it, or you may pass sutures into a protrusion of his bladder or colon.

Close his femoral canal by passing three interrupted monofilament sutures between his inguinal ligament and his pectineal ligament (C, 14-16). Don't go too far laterally with them, or you may constrict his femoral vein.

ALTERNATIVE LOTHEISSEN APPROACH [s7]THROUGH THE POSTERIOR WALL OF HIS INGUINAL CANAL Strangulated gut and omentum may be more easily dealt with by this method, than by the ''standard approach' described above.

Make an incision 1 to 2 cm above his inguinal ligament, as for a strangulated inguinal hernia (14.6). Sweep away the superficial fatty tissue from his external oblique in the lower wound flap, until you come to the bulging femoral hernia below his inguinal ligament.

Deal with the hernial sac as above.

Open up his inguinal canal as for an inguinal hernia. Hold his cord out of the way, and incise its posterior wall (his conjoint tendon and transversalis fascia medially and his transversalis fascia only laterally). Make a 2.5 cm incision 5 mm above and parallel to his inguinal ligament. Tie and divide his inferior epigastric artery and vein, that lie deep to his inguinal ligament in the medial border of his internal inguinal ring; then extend the incision laterally to 4 cm. Apply haemostats to its upper and lower edges to hold them apart.

Look for the neck of the hernia from above by gauze dissection. You will find a tongue of peritoneum disappearing into his femoral canal. Working from above and below, and using the methods described above, reduce the hernia and the sac. Be careful to clear the sac from his bladder medially. Deal with strangulated gut or omentum as above.

Transfix, tie, and excise the sac. Use interrupted monofilament to close his femoral canal, by passing sutures between his inguinal ligament and his pectineal ligament. Protect his femoral vein laterally with your finger while you place these sutures. Close the posterior wall of his external oblique aponeurosis as for an inguinal hernia.

DIFFICULTIES [s7]WITH STRANGULATED FEMORAL HERNIAS See also the ''difficulties' at the end of Sections 14.7 and 14.3.

If you CANNOT DILATE UP HIS FEMORAL CANAL ENOUGH to mobilize his strangulated gut, approach it from above. Use blunt dissection to expose the the neck of the sac medial to his femoral vessels.

If this is not successful, cut the medial boundary of his femoral ring under direct vision. Be careful[md]you may meet an abnormal obturator artery (A, Fig 14-18)!

If you still cannot dilate up his femoral canal enough, divide his inguinal ligament[md]this is very rarely necessary. At the end of the operation, suture its free end against his pectineal line, so as to obliterate his femoral canal.