Annals of the Royal College of Surgeons of England (1975) vol 56 ASPECTS OF TREATMENT*
Strangulated obturator hernia R E Jenner FRCS Surgical Registrar, King's College Hospital, Londont
Introduction laterally so that division of the obturator membrane at operation should be in a downAn obturator lernia is defined as one which wards and medial direction when incarcerpasses between the fibrous obturator membrane and the superior pubic ramus of the Obtator Artery pubic bone. Strangulation of small bowel within this rigid fibro-osseous ring is a fre\ Oturator Canal quent complication of obturator herniation and accounts for the appreciable mortality rate. Greater awareness of the condition leading to earlier diagnosis and a planned operation has reduced the mortality from 30% to around io%. Strangulated obturator herniation is principally a condition of elderly women and over 500 cases have been recorded.
Anatomy (see figure) Certain anatomical features of the obturator region influence management. If the tip of the little finger is inserted into the obturator canal of a cadaver one is impressed by the strength of this fibro-osseous ring which, although providing a good barricade against herniation, encourages early strangulation of trapped viscera. Thus there is no place for trusses or the use of taxis because an external truss would not prevent bowel from entering the ring, and once inside the danger from rupture would be high if taxis were used. The obturator canal transmits the obturator nerve and vessels. The nerve commonly lies postero-
C
S~
Middle Fasciculus of Obturator Externus Muscle
The three routes of descent of an obturator hernia: (A) Occupies obturator canal (commonest). (B) Follows the posterior branches of the obturator vessels (rare). (C) Passes beneath the superficial part of the obturator membrane (very rare).
*Fellows interested in submitting papers for consideration with a view to publication in this series should first write to the Editor.
Strangulated obturator herniia
'67
ated bowel has to be freed. In io% of individuials there is a significant arterial anastomosis between the obturator artery and the inferior epigastric artery which is applied to the medial edge of the ring. It is apparent then that a laparotomy approach from above is the only sure way of identifying and observing these structures. Pressure on the nerve by the sac gives rise to obturator neuralgia, which is the basis of the important Howship-Romberg sign. The sac usually occupies the obturator canal (A), being caught between the adductor longus and obturator externus mtuscles and beneath the pectineus. Therefore the sac will become compressed and more painful when the leg is extended, abducted, and internally rotated. Normally the obturator canal is filled with fat and is wider in females, which partly explains the greater incidence in the malnourished and the 6: I female: male ratio.
initestinial obstruction of unknown cause. A barium enlema as ani outpatient showed diverticular disease of the sigmoid colon. She was readmitted 3 months later wvith the same clinical picture as before, but on this occasion she was tender in the right iliac fossa. She failed to settle quickly, and laparotomy was performed through a right lower paramedian incision. The Howship-Romberg sign was negative preoperatively. Laparotomy revealed dilated loops of intestine leading to the pelvis, gentle traction on which ruptured the strangulated portion of bowel, revealing the site of obstruction as the entrance to the right obturator canal. The obturator canal easily admitted the tip of the little finger and the superior pubic ramus forrmed a prominent overhang, making repair difficult. There was no hernia down the contralateral obturator canal. The small intestine was decompressed and a limited small-bowel resection performed. The appendix was also excised. The sac was not excised but the broad ligament was hitched up to cover the defect. Since some soiling occurred the pelvis was drained. There were no postoperative complications and when she was reviewed at 6 months she was well and had regained some of the weight that she had lost.
Case report
Diagnosis Symptoms The case report illustrates the typical clinical features of a strangulated obtuirator hernia. The correct preoperative diagnosis is made in less than `5 % of cases and is probably never made when the hernial sac is empty. In the unobstructed case symptoms are inderinite. Transient bouts of nausea, vomiting, and abdominal pain herald the acute episode of obstruction, in which vomiting may be less prominent than usual if the strangulation is partial (Richter's). The time period over which these events take place leading to stranguilation and operation may vary from days to several years. Over half the patients will give a history of pain along the inside of the thigh or less commonly over the hip joint. Such pains in elderly patients are likely to be ascribed to rheumatism. The pain is said to be aggravated by coughing buit not bv movements of the hip; this is the Howship-Romberg
A woman aged 85 was admitted with a history of intermittent bou's of generalized colicky abdominal pain for several months. On the day before admission she had vomited many times and she had become more constipated than usual. She had lost about stone (6.4 kg) in weight in the preceding 6 months. She had had 6 normal pregnancies and a cholecystectomy and was frequenltly constipated. Examination revealcd a grossly dehydrated and frail elderly woman. The abdomen wvas distended and tympanitic. There was visible peristalsis and the bovel sounds suggested obstruction. Her hernial orifices were intact aind the cholecystectomy scar was rioted. Rectal examination was normal; vaginal examination, however, was omitted. Her haemoglobin concentration was 13.5 g/dl, leucocyte count X io9/l (Io goo/mm3), and blood urea 10.9 8 mmol/l (48 mg/ioo ml). X-ray of the abdomen showed small-intestinal fluid levels and Paget's disease affecting the right side of the pelvis. She was resuscitated with 4 1 of intravenous fluid over the next 24 h. A nasogastric tube was passed and an enema given. She quickly settled and she was taking a light diet on the 5th day. She was discharged week with a diagnosis of resolving home after i
i
268
R E Jenner
sign, which in the presence of a small-bowel obstruction is diagnostic of a strangulated obturator hernia. Examination usually reveals an Signs elderly woman who has lost weight and who has a small-bowel obstruction of unknown cause. The hernial orifices appear to be intact but in such a patient a small lump may be palpable just lateral to the adductor longus tendon in the upper thigh. There is no cough impulse and firm pressure over the pubic ramus above the lump is not painful as would be the case in the presence of a strangulated femoral hernia. In the absence of a lump tenderness medial to the femoral vessels will be another, though less specific, sign. The limb will usually be held in a semiflexed, adduicted, and externally rotated position, partly for comfort and partly from spasm in the muscles supplied by the irritated obturator nerve. A rectal and vaginal examination may clinch the diagnosis. This reveals a tender swelling on the lateral pelvic wall which is best felt vaginally. Investigations are subordinate to clinical methods in diagnosis and the conditions most frequently confused with strangulated obturator hernia are strangulated femoral hernia, femoral lymphadenitis, appendicitis, and sigmoid diverticulitis. The most important aid to preoperative diagnosis is awareness of the condition.
Treatment Operative treatment is the rule once the patient is rehydrated. A Ryle's tube is passed and the bladder catheterized. Some surgeons prefer the Trendelenberg position, but in my opinion this is not essential and may make access to the defect more difficult, particularly if the pubic ramus forms a prominent overhang. A lower midline abdominal incision provides excellent exposure of the constricting ring from above. It can be opened and
closed quickly and is suitable should bowel resection be necessary. In sick elderly patients when speed is important this incision has advantages over the obturator and inguinal approaches which have been described. However, a McEvedy approach might be useful if there is an obvious obturator mass palpable in the thigh. Once the diagnosis is confirmed the strangulated portion of bowel is gently freed. If gangrene is expected then occlusion clamps placed on the strangulated loop will eliminate spillage of intestinal contents. If the incarcerated bowel cannot be delivered easily, then the constriction should be dilated with a finger and pressure applied over the obturator hernia. The combination of pressure from below and gentle traction from above is usually successful. If this fails, then the obturator membrane should be divided under direct vision. This is simpler and more likely to be successful than starting a separate dissection from the thigh below. Once the bowel is reduced resection or plication with Lembert sutures is performed if necessary. Other viscera that have been recorded in obturator hernias are colon, bladder, fallopian tube, ovarv, and Meckel's diverticulum. The sac is inverted using artery forceps and then transfixed and excised. The stump is then sutured to the adjacent peritoneum and this will suffice to prevent a recurrence. If the sac cannot be inverted, as much as possible of it should be freed from the canal and the edges sutured together to close the defect. If the defect is not closed, then there is a high chance of recurrence. A great variety of methods of repair have been described, some of which are ingenious but equally timeconsuming. If there is soiling around the sac due to gangrenous bowel or perforation, then repair is unnecessary as ensuing inflammatory fibrosis will obliterate a small defect. Large
Strangulated obturator hernia defects, however, ought to be repaired. The simplest method is to approximate the margins with interrupted sutures. Alternatively, a nylon darn is performed if the margins prove to be too unyielding.
2
269
Archampong, E Q (I968) Postgraduate Medical Journal, 44, 140-
3 Desmond, A M, and Hutter, F (1948) British Journal of Surgery, 35, 318.
I am grateful to Professor Harold Ellis and Messrs Butterworths for permission to use, as the basis of the figurc, a diagram published in Clinical Surgery, edited by C G Rob and R Smith (vol. 4, p. 246).
4 Kwong, K H, and, Ong, G B (1966) British Journal of Surgery, 53, 23.
Bibliography
6 Zimmerman, L Ml, and Anson, B J (1967) Anatomny and Surgery of Hernia, 2nd edn., p. 337. Baltimore, Williams and Wilkins.
I
Aird, I (1957) Companion in Surgical Studies, 2nd edn., p. 66o. Edinburgh, Livingstone.
5 Watson, L F (1948) Hernia, 3rd edn., p. 457. St Louis, Mosby.
Strangulated obturator hernia R E Jenner FRCS Surgical Registrar, King's College Hospital, Londont
Introduction laterally so that division of the obturator membrane at operation should be in a downAn obturator lernia is defined as one which wards and medial direction when incarcerpasses between the fibrous obturator membrane and the superior pubic ramus of the Obtator Artery pubic bone. Strangulation of small bowel within this rigid fibro-osseous ring is a fre\ Oturator Canal quent complication of obturator herniation and accounts for the appreciable mortality rate. Greater awareness of the condition leading to earlier diagnosis and a planned operation has reduced the mortality from 30% to around io%. Strangulated obturator herniation is principally a condition of elderly women and over 500 cases have been recorded.
Anatomy (see figure) Certain anatomical features of the obturator region influence management. If the tip of the little finger is inserted into the obturator canal of a cadaver one is impressed by the strength of this fibro-osseous ring which, although providing a good barricade against herniation, encourages early strangulation of trapped viscera. Thus there is no place for trusses or the use of taxis because an external truss would not prevent bowel from entering the ring, and once inside the danger from rupture would be high if taxis were used. The obturator canal transmits the obturator nerve and vessels. The nerve commonly lies postero-
C
S~
Middle Fasciculus of Obturator Externus Muscle
The three routes of descent of an obturator hernia: (A) Occupies obturator canal (commonest). (B) Follows the posterior branches of the obturator vessels (rare). (C) Passes beneath the superficial part of the obturator membrane (very rare).
*Fellows interested in submitting papers for consideration with a view to publication in this series should first write to the Editor.
Strangulated obturator herniia
'67
ated bowel has to be freed. In io% of individuials there is a significant arterial anastomosis between the obturator artery and the inferior epigastric artery which is applied to the medial edge of the ring. It is apparent then that a laparotomy approach from above is the only sure way of identifying and observing these structures. Pressure on the nerve by the sac gives rise to obturator neuralgia, which is the basis of the important Howship-Romberg sign. The sac usually occupies the obturator canal (A), being caught between the adductor longus and obturator externus mtuscles and beneath the pectineus. Therefore the sac will become compressed and more painful when the leg is extended, abducted, and internally rotated. Normally the obturator canal is filled with fat and is wider in females, which partly explains the greater incidence in the malnourished and the 6: I female: male ratio.
initestinial obstruction of unknown cause. A barium enlema as ani outpatient showed diverticular disease of the sigmoid colon. She was readmitted 3 months later wvith the same clinical picture as before, but on this occasion she was tender in the right iliac fossa. She failed to settle quickly, and laparotomy was performed through a right lower paramedian incision. The Howship-Romberg sign was negative preoperatively. Laparotomy revealed dilated loops of intestine leading to the pelvis, gentle traction on which ruptured the strangulated portion of bowel, revealing the site of obstruction as the entrance to the right obturator canal. The obturator canal easily admitted the tip of the little finger and the superior pubic ramus forrmed a prominent overhang, making repair difficult. There was no hernia down the contralateral obturator canal. The small intestine was decompressed and a limited small-bowel resection performed. The appendix was also excised. The sac was not excised but the broad ligament was hitched up to cover the defect. Since some soiling occurred the pelvis was drained. There were no postoperative complications and when she was reviewed at 6 months she was well and had regained some of the weight that she had lost.
Case report
Diagnosis Symptoms The case report illustrates the typical clinical features of a strangulated obtuirator hernia. The correct preoperative diagnosis is made in less than `5 % of cases and is probably never made when the hernial sac is empty. In the unobstructed case symptoms are inderinite. Transient bouts of nausea, vomiting, and abdominal pain herald the acute episode of obstruction, in which vomiting may be less prominent than usual if the strangulation is partial (Richter's). The time period over which these events take place leading to stranguilation and operation may vary from days to several years. Over half the patients will give a history of pain along the inside of the thigh or less commonly over the hip joint. Such pains in elderly patients are likely to be ascribed to rheumatism. The pain is said to be aggravated by coughing buit not bv movements of the hip; this is the Howship-Romberg
A woman aged 85 was admitted with a history of intermittent bou's of generalized colicky abdominal pain for several months. On the day before admission she had vomited many times and she had become more constipated than usual. She had lost about stone (6.4 kg) in weight in the preceding 6 months. She had had 6 normal pregnancies and a cholecystectomy and was frequenltly constipated. Examination revealcd a grossly dehydrated and frail elderly woman. The abdomen wvas distended and tympanitic. There was visible peristalsis and the bovel sounds suggested obstruction. Her hernial orifices were intact aind the cholecystectomy scar was rioted. Rectal examination was normal; vaginal examination, however, was omitted. Her haemoglobin concentration was 13.5 g/dl, leucocyte count X io9/l (Io goo/mm3), and blood urea 10.9 8 mmol/l (48 mg/ioo ml). X-ray of the abdomen showed small-intestinal fluid levels and Paget's disease affecting the right side of the pelvis. She was resuscitated with 4 1 of intravenous fluid over the next 24 h. A nasogastric tube was passed and an enema given. She quickly settled and she was taking a light diet on the 5th day. She was discharged week with a diagnosis of resolving home after i
i
268
R E Jenner
sign, which in the presence of a small-bowel obstruction is diagnostic of a strangulated obturator hernia. Examination usually reveals an Signs elderly woman who has lost weight and who has a small-bowel obstruction of unknown cause. The hernial orifices appear to be intact but in such a patient a small lump may be palpable just lateral to the adductor longus tendon in the upper thigh. There is no cough impulse and firm pressure over the pubic ramus above the lump is not painful as would be the case in the presence of a strangulated femoral hernia. In the absence of a lump tenderness medial to the femoral vessels will be another, though less specific, sign. The limb will usually be held in a semiflexed, adduicted, and externally rotated position, partly for comfort and partly from spasm in the muscles supplied by the irritated obturator nerve. A rectal and vaginal examination may clinch the diagnosis. This reveals a tender swelling on the lateral pelvic wall which is best felt vaginally. Investigations are subordinate to clinical methods in diagnosis and the conditions most frequently confused with strangulated obturator hernia are strangulated femoral hernia, femoral lymphadenitis, appendicitis, and sigmoid diverticulitis. The most important aid to preoperative diagnosis is awareness of the condition.
Treatment Operative treatment is the rule once the patient is rehydrated. A Ryle's tube is passed and the bladder catheterized. Some surgeons prefer the Trendelenberg position, but in my opinion this is not essential and may make access to the defect more difficult, particularly if the pubic ramus forms a prominent overhang. A lower midline abdominal incision provides excellent exposure of the constricting ring from above. It can be opened and
closed quickly and is suitable should bowel resection be necessary. In sick elderly patients when speed is important this incision has advantages over the obturator and inguinal approaches which have been described. However, a McEvedy approach might be useful if there is an obvious obturator mass palpable in the thigh. Once the diagnosis is confirmed the strangulated portion of bowel is gently freed. If gangrene is expected then occlusion clamps placed on the strangulated loop will eliminate spillage of intestinal contents. If the incarcerated bowel cannot be delivered easily, then the constriction should be dilated with a finger and pressure applied over the obturator hernia. The combination of pressure from below and gentle traction from above is usually successful. If this fails, then the obturator membrane should be divided under direct vision. This is simpler and more likely to be successful than starting a separate dissection from the thigh below. Once the bowel is reduced resection or plication with Lembert sutures is performed if necessary. Other viscera that have been recorded in obturator hernias are colon, bladder, fallopian tube, ovarv, and Meckel's diverticulum. The sac is inverted using artery forceps and then transfixed and excised. The stump is then sutured to the adjacent peritoneum and this will suffice to prevent a recurrence. If the sac cannot be inverted, as much as possible of it should be freed from the canal and the edges sutured together to close the defect. If the defect is not closed, then there is a high chance of recurrence. A great variety of methods of repair have been described, some of which are ingenious but equally timeconsuming. If there is soiling around the sac due to gangrenous bowel or perforation, then repair is unnecessary as ensuing inflammatory fibrosis will obliterate a small defect. Large
Strangulated obturator hernia defects, however, ought to be repaired. The simplest method is to approximate the margins with interrupted sutures. Alternatively, a nylon darn is performed if the margins prove to be too unyielding.
2
269
Archampong, E Q (I968) Postgraduate Medical Journal, 44, 140-
3 Desmond, A M, and Hutter, F (1948) British Journal of Surgery, 35, 318.
I am grateful to Professor Harold Ellis and Messrs Butterworths for permission to use, as the basis of the figurc, a diagram published in Clinical Surgery, edited by C G Rob and R Smith (vol. 4, p. 246).
4 Kwong, K H, and, Ong, G B (1966) British Journal of Surgery, 53, 23.
Bibliography
6 Zimmerman, L Ml, and Anson, B J (1967) Anatomny and Surgery of Hernia, 2nd edn., p. 337. Baltimore, Williams and Wilkins.
I
Aird, I (1957) Companion in Surgical Studies, 2nd edn., p. 66o. Edinburgh, Livingstone.
5 Watson, L F (1948) Hernia, 3rd edn., p. 457. St Louis, Mosby.
![[Strangulated obturator hernia: about two cases].](/assets/img/hold.png)
