ORIGINAL ARTICLE
Diagnosis and treatment of obturator hernia
Takamori Nakayama, Seiji Kobayashi,1 Kou Shiraishi, Takao Nishiumi, Syunji Mori, Kiyoshi Isobeand Yoshiaki Furuta
Departments of Surgery and 1Radiology, Shizuoka Red Cross Hospital, Shizuoka city, Shizuoka, Japan(Received for publication on June 21, 2002)

Abstract. Obturator hernia is a rare type of hernia, but it is a signiﬁcant cause of intestinal obstruction
due to the associated anatomy. Correct diagnosis and treatment of obturator hernia is important, because delay can lead to high mortality. Twelve patients with obturator hernia were managed during a
11-year period, including 11 women and 1 man with a mean age of 82 years. We compared our experience with the previously published data to establish standards for the diagnosis and treatment of thishernia. All 12 patients presented with intestinal obstruction. The median interval from admission tooperation was 2 days. The Howship-Romberg sign was positive in 5 patients. A correct diagnosis wasmade in all 8 patients who underwent pelvic CT scanning. Surgery was performed via an abdominalapproach (n F 7) or an inguinal approach (n F 5). The hernial oriﬁce was closed using the uterine
fundus (n F 6), a patch (n F 5), and direct suture (n F 1). Mean follow-up time was 33 months, and norecurrence has been detected. The poor physical condition of patients might have led to a delay in diagnosis and treatment. In troubled patients with nonspeciﬁc intestinal obstruction, CT scanning isuseful for the early diagnosis of obturator hernia. Correct CT diagnosis of obturator hernia allows us toselect the inguinal approach combined with patch repair, which is minimally invasive surgery. (Keio JMed 51 (3): 129–132, September 2002)
Key words: obturator hernia, diagnosis, treatment, CT (scanning)

Introduction
The obturator foramen is the largest foramen in thebody, being formed by the rami of the ischium and thepubis. The obturator canal is 2–3 cm long and 1 cm
wide, and it contains the obturator nerve and vessels.1
Obturator hernia was ﬁrst described in 1724, and wasrecently reported to account for 0.05–0.14% of allhernias and 0.2–1.6% of all small bowel obstruction.2,3
A total of 600 cases were detected by a search of the
English literature from 1980 to 1992.2 There are threestages of obturator hernia.1 The ﬁrst stage is the entrance of preperitoneal tissue into the pelvic oriﬁce ofthe obturator canal, while the second stage involves thedevelopment of a dimple in the peritoneum overlying
the canal. The third stage is the onset of symptoms
produced by entrance of an organ into the canal. The
hernia sac may contain the small bowel, large bowel,
omentum, fallopian tube, or appendix.1 In more thanhalf of all patients with obturator hernia, the presenting
symptom is partial small bowel obstruction.1

We compared our experience with the previously
published data to establish standards for the diagnosis
and treatment of this hernia.

Patients and Methods
Twelve patients with obturator hernia were managedat Shizuoka Red Cross Hospital during an 11-year
period from September 1991 to February 2002 (Table1). Their clinical records were retrospectively reviewed
to determine the age, gender, body weight, height, previous illnesses, history of delivery for women, symptoms, operative details, and postoperative course.
The mean age was 82 years (range: 68–95 years).
There were 11 women and 1 man. The mean weight was
33 kg (range: 25–48 kg), the mean height was 144 cm(range: 138–148 cm), and the mean body mass index(BMI) was 15 (patient range: 13–19; normal range:18–26). The mean number of deliveries for women was
3.1 (range: 0–6).

Reprint requests to: Dr. Takamori Nakayama, Department of Surgery, Shizuoka Red Cross Hospital, 8-2, Ohtemachi, Shizuoka city, Shizuoka,
420-0853, Japan
129

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Nakayama T, et al: Obturator hernia

Table 1

Clinical and Surgical Details in 12 Patients

Patient
No

Age/
Gender123456
78
910
11
12

92/F
90/F
87/F
85/F
95/F
76/F
84/F
84/F
68/F
73/F
76/F
73/M

CT

Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No

HRS

Positive
Positive
NA
Negative
NA
NA
NANA
Positive
Positive
Positive
NA

Preoperative
diagnosis

Interval (days)

Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
NoA

B

C0116660393677
1010110421428
15
62101
1030
7––––

Operative
approach

Inguinal
Inguinal
Inguinal
Inguinal
Inguinal
Abdominal
Abdominal
Abdominal
Abdominal
Abdominal
Abdominal
Abdominal

Anesthesia

LumbarLumbarLumbar
GeneralGeneralGeneralGeneralGeneralGeneralGeneralGeneralGeneralStage
rightleft–
33–
322320
3
33––
3–
3303
300

Bowel
obstructionBowelresection

PartialPartialPartialComplete
PartialComplete
PartialComplete
PartialPartialPartialPartial

No
No
No
Yes
No
Yes
Yes
Yes
Yes
No
No
No

HRS; Howship-Romberg sign. NA; Data was not available. Interval A; Interval from the onset of symptoms to admission. Interval B; Intervalfrom admission to operation. Interval C; Interval from CT to operation.

Computed tomography

Results
Clinical presentation
The median interval from the onset of symptoms toadmission was 7 days (range: 0–677 days). All 12
patients presented with intestinal obstruction. One patient had a palpable mass located medial to the femoral
artery (Table 1, Patient No. 1), while the HowshipRomberg sign was present in 5 patients. There was ahistory of previous attacks and subsequent remission in
5 patients. Eleven patients had concomitant medical
problems on admission (Table 2), and their poor physical condition might have led to a delay in diagnosis andtreatment. None of the patients had undergone previous abdominal surgery.

Table 2 Concomitant Medical Problems in
12 Patients
DiseasePresence (n ¼ 11)
Hypertension
Kyphoscoliosis
Lung disease
Ischemic heart disease
Cardiac arrhythmia
Arthritis
Cerebral vascular disease
Duodenal ulcer
Absence (n ¼ 1)
TotalNo.

5431111117A correct diagnosis was made in 11 patients (11/12,91%). All 8 patients who underwent pelvic CT scanningreceived a correct diagnoses (Fig. 1A, 1B). In theremaining 4 patients who did not undergo pelvic CT,
the correct diagnosis was made in 3 because of theHowship-Romberg sign. In one patient (Table 1, Patient No. 12), the diagnosis was not made before surgery for acute intestinal obstruction.
Operative ﬁndings
The median interval from admission to operation
was 2 days (range: 0–28 days). The median intervalfrom CT to operation (n ¼ 8) was 1 day (range: 0–7days). After CT scanning, a delayed operation wasperformed for two patients (Table 1, Patient No. 6 and8). One patient (Table 1, No. 6) complained of an abdominal mass at for right lower quadrant and was initially scheduled to receive surgery ascending coloncancer, but CT failed to show ascending colon cancer
and revealed the presence of obturator hernia. The patient underwent surgery for obturator hernia on theinitially planned day. Patient (Table 1, No. 8) at ﬁrst
refused all treatment for intestinal obstruction, butconsented later. The patient underwent surgery on theconsented day.
Surgery was performed via an abdominal approach(n ¼ 7) or an inguinal approach (n ¼ 5). The hernial sac
contained the small bowel in all 12 patients (stage 3hernia). Nine patients had evidence of partial bowel
obstruction. The hernia was on the right side in 10

Keio J Med 2002; 51 (3): 129–132

131Fig. 1 Computed tomography of strangulated obturator hernia. (A) Computed tomography (Table 1, Patient No. 4) reveals a mass lying between the obturator externus and pectineus muscles. (B) Computed tomography (Table 1, Patient No. 6) reveals a mass on the left side and aﬂuid collection on the right side.

patients and on the left side in 6 patients. In 3 of the 7patients who were operated on via an abdominal
approach, bilateral obturator hernias were detected. In
these 3 patients, one each of the hernias was stage 2 andstage 3, respectively. Small bowel resection was performed in 5 patients. The hernial oriﬁce was closed
using the uterine fundus (n ¼ 6), a patch (n ¼ 5), andby direct suture (n ¼ 1).
Morbidity and mortality
The mean hospital stay was 30 days (range: 8–50days). Postoperative complications included wound infection (n ¼ 2) and pneumonia (n ¼ 1). The patientcomplaining of postoperative pneumonia died 2 months
after surgery, and had a history of emphysema andrequired postoperative ventilation (Table 1, Patient No.
12). No recurrence has been detected with the meanfollow-up of 33 months (range: 1–125 months) for thesurviving 11 patients.
Discussion
More than 90% of patients with obturator hernia
present with intestinal obstruction that causes pain,nausea, and vomiting.2 One third of the patients have ahistory of previous attacks of small bowel obstruction.1
The symptoms of obstruction may subside initially, because transient herniation can resolve spontaneously.
Obturator hernia occurs most commonly in debilitatedelderly people, because of loss of the protective fat in
the obturator canal.4 Women are affected 6–9 times
more often than men, because of their broader pelvis
and larger obturator canal.5,6 Chronic lung disease,constipation, kyphoscoliosis and pregnancy can all predispose to herniation by increasing the intra-abdominalpressure.7 Herniation is more frequent on the rightside, because the sigmoid colon tends to prevent it on
the left. These characteristic clinical features of mostprevious series corresponded to those of our series.
There was only one made case of man in our series,
who underwent emergency surgery for acute intestinal
obstruction, and died of pneumonia 2 months after
surgery (Table 1, Patient No. 12).
Obturator hernia seldom causes swelling in Scarpa’s
triangle as it is located deeply between the pectineus
and adductor longus muscles.1 Palpation from the rectum or vagina can conﬁrm the presence of an obturator
hernia, if the suspicion is already in the examiner’s
mind. However, physical ﬁndings of obturator hernia
are relatively nonspeciﬁc, and the chronic pain is sometimes misinterpreted as rheumatoid arthritis.4 Preoperative diagnosis is often delayed, and is made correctly
in only 10–30% of cases.1,6 Herniography revealed 15
obturator hernias in 850 patients with groin pain, butcould not be used as an indicator for surgery because
the detected hernias were mostly unrelated to the patient’s symptoms.8
Recently, diagnosis has been successfully achievedby CT scanning, which can clearly demonstrate an
obturator hernia as a low-density mass lying between
the obturator externus and pectineus muscles.9 CT wasperformed in 8 patients with 100% accuracy in ourseries. We recommend that in debilitated elderly multipregnant women troubled with intestinal obstruction,
CT scanning should be carried out ﬁrst. Because ofmany medical problems in such patients, other examinations may be too hard and invasive to carry out.
The Howship-Romberg sign is pain extending down
the inner surface of the thigh to the knee, which is
caused by hernial irritation of the anterior division of
the obturator nerve.6 Flexion of the thigh relieves thepain, while extension, adduction, or medial rotation
exacerbates it. The Howship-Romberg sign is pathognomonic of obturator hernia and is present in 25–50%
of patients.1,2 However, the Howship-Romberg signlately tended to be neglected in our series because ofearly diagnosis by CT. Before relying on CT diagnosis,

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the positive Howship-Romberg sign (n ¼ 3) was more
frequently observed in our series since more careful attention might have been paid in patients troubled with
nonspeciﬁc intestinal obstruction.
The Hannington-Kiff sign refers to an absent adductor reﬂex in the thigh.10 A difference compared withthe opposite side and a normal ipsilateral patellar reﬂex
are indicators of compression of the obturator nerve.
The Hannington-Kiff sign is more speciﬁc than theHowship-Romberg sign, but less widely known.10 Physical examination failed to detect the Hannington-Kiffsign in our series. It is important to keep these traditional signs in mind before undertaking CT.
Strangulation of the herniated viscus eventuallyoccurs and surgical intervention is the only effectivetreatment. The surgical approach is selected dependingon the preoperative diagnosis, with the abdominal
approach being most often favored when the diagnosis
is unclear. The retropubic approach, obturator approach, and inguinal approach can all give a good result, if a correct diagnosis is made before surgery.11
Laparoscopic surgery has recently made its debut, but
technical complications occurred in 5.3% of patients.12
Direct suture of the fascial defect is considered sufﬁcient for small hernias, but primary closure of larger
defects is difﬁcult because the foramen is bordered bybone and spanned by the obturator membrane.13 The
reported techniques for closure include ﬂaps of periosteal fascia, use of the bladder wall or uterine fundus,
and patching with Marlex or Teﬂon.14 CT deﬁnitely
detected obturator hernia in 8 patients from our series.
Five of these 8 patients had surgery via the inguinal
approach combined with patch repair under lumbar
anesthesia (n ¼ 3) or general anesthesia (n ¼ 2). Although there is generally a 6% incidence of bilateral
hernia,5 we recommend patients with obturator hernia
to check the opposite site since three bilateral hernias
were conﬁrmed at operation via the abdominal approach in our series.
Half of the patients required bowel resection in thepreviously reported series, because obturator hernia isassociated with bowel strangulation.15 After rupture ofa strangulated bowel and the onset of peritonitis, thehernial sac should be opened to avoid abscess formation, as the recurrence rate for unclosed defects is relatively low (10%).16 Five patients (5/12, 41%) required
bowel resection in our series. We found the trend toward bowel resection correlated with the prolonged

Nakayama T, et al: Obturator hernia

interval from the onset of symptoms to admission andthose from admission to operation. However, CT ﬁndings failed to reveal the severity of bowel obstructionor the indication for bowel resection in our series. TheHowship-Romberg sign did not correlate with bowel
resection, either. Namely, patient with this negativesign (n ¼ 1) received bowel resection, whereas only one
bowel resection was required in patients with this positive sign (n ¼ 5). Because data regarding the HowshipRomberg sign was not fully available in our series, weneed to investigate more cases to assess the signiﬁcanceof the Howship-Romberg sign.
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