Peritoneography (Herniography) for Detecting Occult Inguinal Hernia in Patients with Inguinodynia

Abstract

Objective

To evaluate the usefulness of peritoneography in patients referred with inguinal pain (inguinodynia) and clinically absent inguinal hernia on physical examination.

Summary Background Data

In patients with chronic groin pain, peritoneography is a seldom-used yet available technique that can detect an occult inguinal hernia. The value of peritoneography in the diagnosis of occult inguinal hernia has been previously shown.

Methods

During a 60-month period, 80 consecutive patients with complaints of persistent inguinal pain (inguinodynia) without evidence of hernia on clinical examination were referred for outpatient evaluation by peritoneography. Twenty-nine patients had prior inguinal surgery in the region of their current pain. Peritoneography was performed using a midline or paraumbilical approach. Radiographs were obtained with patients in prone and prone oblique positions with the head elevated 20° to 25°, both with and without provocative maneuvers. All available records were retrospectively reviewed for radiographic findings and outcome.

Results

Of the 80 patients undergoing peritoneography, 36 (45%) were diagnosed radiographically to have inguinal hernias that were not detectable clinically. Twenty-seven of these patients subsequently underwent inguinal exploration, and a hernia was confirmed in 24 (89%). Of the patients having prior inguinal surgery in the region of their pain, 12/29 (41%) were diagnosed by peritoneography with a hernia. Two complications (2.5%), both colon perforations that did not require significant intervention, occurred as a result of peritoneography.

Conclusions

Peritoneography is highly reliable for detecting clinically occult inguinal hernia and has a low complication rate. Its usefulness is shown in a prospective consecutive series for detection of occult hernias in patients with chronic inguinal pain. The authors conclude that peritoneography is a safe and useful diagnostic test in the setting of persistent inguinal pain and a negative clinical examination.

Peritoneography involves the intraperitoneal injection of nonionic contrast for evaluation of the abdominal parietes. When used selectively for evaluation of the inguinal region and pelvic floor, it is termed herniography. ¹ Herniography initially gained popularity for use as a diagnostic modality in children, and its benefit for the diagnosis of bilateral congenital hernias in that population has been previously reported. ^2,3 More recently, herniography has also been applied to the adult population. In this regard it can be used to evaluate patients for acute, chronic, or recurrent hernia. In addition, it may be a useful adjunct for the obese patient, where body habitus limits physical examination findings. The value of peritoneography in the diagnosis of occult inguinal hernia has been previously shown by a few clinical investigations. Hernia detection rates in the setting of chronic inguinal pain are reported in the range of 11% to 43%. ^4–8 Most of these early reports in adults were from European centers. The technique has not gained popularity and is not used at most medical centers in the United States.

Besides herniography, other radiologic imaging such as ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) are established and accepted procedures for imaging hernias if there is diagnostic uncertainty. Recent improvements in contrast and spatial resolution in cross-sectional imaging have improved diagnosis. ^9–11

We sought to evaluate the usefulness of herniography for the detection of occult inguinal hernias in the setting of chronic inguinal pain and absence of hernia on physical examination performed by an experienced surgeon (J.R.S.), surgical residents, and referring physicians. In addition, we comment on its use in patients who have chronic inguinal pain after prior inguinal surgery and evaluate its safety profile.

METHODS

During a 60-month period ending in May 1999 , we referred 80 patients to our interventional radiology department for outpatient peritoneography. The mean age was 39 years (range 16–74). There were 63 male patients and 17 female patients evaluated. All of these patients had persistent inguinal pain with no hernia detectable on physical examination by numerous physicians. Of these 80 patients, 29 (36%) had prior inguinal hernia surgery in the region of their chronic pain.

Herniography Technique

The technique of herniography is performed as follows: an initial physical examination of the inguinal regions is performed standing and then supine to exclude hernia and to evaluate for other causes of inguinal pain related to the symphysis pubis, adductor musculature, and hip joints. With the patient in the supine position on the radiographic tilt table, the patient is asked to elevate head and shoulders off the table, and the tensed abdomen is examined. The midline region of the supraumbilical linea alba and the linea semilunaris at the lateral margin of the rectus sheath adjacent to the umbilicus are identified and marked where possible, depending on operator preference. An intravenous line is instituted that can be used for conscious sedation (rarely needed) or treatment of vagal reactions (again, rarely needed), reactions to the local anesthetic or the contrast medium. The chosen area is prepared and draped in sterile fashion, and the skin and subcutaneous tissues down to the peritoneum are infiltrated with 1% Xylocaine (Abbott Laboratories, Chicago, IL). A small dermatotomy is made and the 7- or 12-cm 21-gauge micropuncture needle (depending on body habitus) from a 10- or 15-cm Micropuncture set (Cook, Inc, Bloomington, IN) is inserted in an oblique fashion (not vertically) until the patient’s face registers the characteristic grimace and the characteristic pop is felt, indicating passage of the needle tip through the peritoneum. At this time, a small amount of contrast is injected by hand under fluoroscopy. If necessary, the needle is repositioned until the injected contrast shows the characteristic interloop appearance on fluoroscopy, indicating the needle tip is within the peritoneal cavity and not within the parietes, the greater omentum, and the small bowel mesentery or within the bowel lumen. The 0.018-inch-diameter guidewire from the micropuncture set is passed through the needle and the needle is removed. The 4F micropuncture sheath/dilator is passed over the wire into the peritoneal cavity, the wire and dilator are removed, and then 150 mL nonionic contrast medium (Omnipaque 300, Nycomed, Princeton, NJ) is injected by hand through the sheath into the peritoneal cavity. The sheath is capped off and left in situ, covered by a sterile occlusive dressing. The patient is turned into the prone position and the head of the table is elevated 20° to 25° to optimally pool the intraperitoneal contrast over the inguinal regions. Radiographs are then obtained with the patient in prone and prone oblique positions at rest and during provocative maneuvers such as coughing, sniffing, Mueller maneuver (forced inspiration against a closed glottis), and straining or Valsalva maneuver (forced expiration against a closed glottis). In addition, the patient is occasionally asked to elevate up on knees and elbows to relieve compression from obesity on the inguinal regions (a cause of false-negative results). Cross-table lateral radiographs are occasionally used as well. As an important adjunct to the examination, the patient is asked to point with a single index finger or to place a radiographic marker at the site of his or her pain, and a radiograph is obtained for correlation. In male patients, standing images are sometimes useful. In male patients, the scrotum should be briefly evaluated with fluoroscopy after all the provocative maneuvers to see whether any contrast has entered the scrotum. This can indicate hernia when the neck is not apparent or compressed. If there is a teat appearance in the supravesical or medial or lateral inguinal fossae, the patient can be turned supine and the feet elevated 20° to 25° and air or CO₂ can be injected through the indwelling sheath. This occasionally detects a hernia, the sac filling with negative contrast. This usually requires abdominal distention with gas.

The entire procedure takes approximately 20 to 30 minutes. When the procedure is complete, the 4F sheath is removed and a sterile dressing is applied.

RESULTS

Of the 80 herniograms performed in symptomatic patients with ipsilateral inguinodynia, an occult inguinal hernia was diagnosed in 36 (45%). Of the 36 positive studies, 24/51 (47%) were in patients without previous hernia repair, whereas in the 29 patients who had prior inguinal surgery, 12 of 29 (41%) showed an occult inguinal hernia. Examples of these positive herniographic findings can be seen in Figures 1 and 2. Hernias diagnosed by herniography are all significant radiographic findings, and our radiologists have never mentioned a subtle anatomic variation such as a patent processus vaginalis. In our patients a single asymptomatic contralateral inguinal hernia was seen; this is not included in our database.

Figure 1. (A) Normal study on a standard peritoneogram. In contrast, a positive study reveals an obvious indirect inguinal hernia on both the posteroanterior (B) and oblique (C) images (arrows).

Figure 2. Importance of a provocative maneuver. (A) Normal study with the patient at rest. (B) The same patient performs a Valsalva maneuver, revealing an obvious indirect occult inguinal hernia (arrow).

Of the 36 patients with a positive herniogram, 27 elected to have herniorrhaphy at our institution; 9 patients (students) deferred because of HMO restrictions went to their own community. Of the 27 groin explorations performed by the senior author (J.R.S.), direct or indirect inguinal hernias were confirmed in 24 of 27 (89%), with three false-positives. Two of these false-positives were in patients who had multiple (more than two) prior inguinal hernia surgeries. There was a single false-negative herniography. Two complications (2.5%), confined microbowel perforations shown by hand injection of contrast under fluoroscopy, resulted from peritoneography in this series. One patient had a negative laparoscopy and prophylactic antibiotics; the other remained asymptomatic. The death rate from peritoneography was zero.

All of our 24 patients who underwent successful herniorrhaphy at our institution recovered without complications with resolution of their chronic inguinodynia.

DISCUSSION

In this series, peritoneography for chronic inguinal pain and a negative clinical examination by multiple physicians and surgical residents resulted in occult inguinal hernia diagnosis in 45% of patients. Similar findings are noted in patients who had had prior inguinal surgery. As depicted in Table 1, prior published series of herniograms showed an 11% to 43% range of positive hernia detection rates. Various authors, but not exclusively, whose series are at the lower range of positivity obviously question the benefit of recommending herniography as a routine test, even in the difficult patient. Our data correlate with those authors who report a high rate of occult hernia detection by peritoneography. This may be due to our patient population, where hernia detection by physical examination was particularly difficult because of large body habitus or muscular athletes. In addition, the ability to detect an occult hernia by peritoneography relies on the interest and skill of the interventional radiologist. Unless the hernia is obvious on peritoneography, the detection of small hernias, especially in patients having had multiple prior surgeries, may be difficult and operator-dependent. This is suggested in our series, where two of the three false-positive findings were noted in patients who had had multiple prior inguinal surgeries. However, a history of prior inguinal surgery does not appear to alter the ability to detect occult hernias, as shown by 12 positive studies in the 29 patients who had previous surgery. This finding has been confirmed by other authors ¹² and appears to be reliable even in the presence of the mesh plug herniorrhaphy. ¹³ To date we are aware of only one false-negative finding in a university student/soccer player with chronic inguinal pain. This patient had a negative herniogram but was eventually operated on by the senior author (J.R.S.) for possible pubalgia, and a small indirect hernia was found. ¹⁴ The false-positive herniography rate in the literature varies from 0% to 18.7% and the false-negative rate from 2% to 7.9%. False-negative reports are thought to be a result of fat plugging the hernial orifice. ^15,16,17

Table 1. PERITONEOGRAPHY FOR OCCULT HERNIA

Two complications occurred in the first 15 patients in this series. Both were colon perforations and both were recognized immediately as microcolon perforations by the radiologist. One of these patients was observed, and the other underwent a negative diagnostic laparoscopy. These results are consistent with other publications. ¹¹ There had been no further complications in more than 100 consecutive examinations.

The evaluation of the patient referred for chronic inguinal pain (inguinodynia) is often difficult, especially when physical examination findings are limited. This is often the case in the female patient or where body habitus makes examination less than ideal. Peritoneography in these patient populations may be especially useful. Our radiographic results avoided recommending unnecessary surgical exploration in 55% of patients. Once occult hernia has been ruled out, these difficult and frustrated patients can then be referred for pain management and physical therapy, can be treated with appropriate medications, or can undergo possible further diagnostic testing as deemed appropriate by the primary physician. Although peritoneography is an invasive test, it is extremely well tolerated by patients and is safe, with few complications and no reported deaths.

Many radiologists believe that in the future cross-sectional imaging may eventually replace herniography, despite the low 1% incidence of accidental bowel puncture. Cross-sectional computed tomography or magnetic resonance imaging is currently recommended for acutely strangulated hernia in the obese patient or in patients at high anesthetic risk with reducible direct hernias in whom surgery may not be mandatory. ¹¹

In our experience, peritoneography for detection of occult inguinal hernia is a useful modality in patients with chronic inguinal pain (inguinodynia) and a negative clinical examination, in patients with and without prior inguinal surgery. In this select population, relief of chronic inguinodynia follows conventional herniorrhaphy.