G Sen**, R Lochan*, B V Joypaul
Department of Surgery, South Tyneside District Hospital, South Shields; **Department of Surgery Hartlepool General Hospital, Hartlepool; *Department of Surgery, Freeman Hospital, Newcastle upon Tyne
Correspondence to: R Lochan, HPB Unit, Dept of Surgery (Level 4 Secretaries Office), Freeman Hospital, High Heaton, Newcastle upon Tyne NE7 7DN Tel: 0191 2448427 Fax: 0191 2231483 Email: rajiv.lochan@nuth.northy.nhs.uk
SMJ 2005 50(3): 124-125
Abstract
Background: Spigelian hernia is a rare clinical condition. It is difficult to diagnose in absence of obvious clinical signs. Ultrasound scan, crosssectional imaging and contrast studies like herniography have been widely used for detecting occult abdominal wall hernias in symptomatic patients. Aim and methods: We present our experience of detecting a clinically occult Spigelian hernia in a 56-year-old symptomatic male patient, who had concomitant left sided inguinal and Spigelian hernias. In this patient, the Spigelian hernia was not detected on ultrasound scan. We also present a review of literature on the role of herniography in the diagnosis of this rare condition. Results and Conclusion: Herniography is a sensitive investigation for evaluation of occult hernias. However, it is an invasive contrast study and therefore must be used selectively. Non-invasive real-time imaging like ultrasonography remains the first line of investigation for detecting occult hernias.
Keywords: Spigelian hernia, herniography, occult hernia
Introduction
Spigelian hernia is a rare condition, which is often clinically elusive. It is a hernia occuring through the “Spigelian aponeurosis”, a part of the anterior abdominal wall between the lateral border of rectus abdominis muscle and the linea semilunaris, usually at or below the level of the umbilicus.1 It is often impossible to distinguish from an inguinal hernia and it can be difficult to diagnose clinically in absence of obvious signs, especially in symptomatic patients. We present a patient with concomitant inguinal and spigelian hernias diagnosed on herniography. We have also reviewed the role of herniography to diagnose this rare condition.
Case report
A 56-year-old seaman presented with lower abdominal discomfort and pain for six months. He also noticed a vague swelling in the left lower abdomen for two months, although the swelling was not always palpable. This swelling was at the level of the umbilicus. On examination he had a reducible left inguinal hernia. No obvious lesion was palpable at the site of his predominant symptom, which was at a higher level than the clinically apparent left inguinal hernia. A provisional diagnosis of spigelian hernia was made and an ultrasound scan was requested to confirm it. The scan failed to demonstrate any obvious Spigelian hernia or a defect in the rectus sheath. Upon the recommendation of the radiologists, he underwent a herniography. This revealed the presence of two different hernias on the left side, one above the other (Fig 1); thus confirming the concomitant presence of a spigelian and an inguinal hernia. The spigelian hernia was confirmed on surgical exploration (Fig 2) and both hernias had a tension-free repair using polypropylene mesh. The patient has remained symptom free 24 months after surgery.
Discussion
Peritoneography is a radiological investigation involving intra-peritoneal injection of non-ionic contrast for assessment of the abdominal wall. When used specifically for evaluation of hernia in the inguinal and pelvic regions, the technique is termed herniography.2 First described in 1967, herniography was mainly used in paediatric surgery for detection of contralateral inguinal hernia.3 Nowadays, this investigation is being used in the adult obese population where clinical assessment can often be very difficult. Increasingly, the technique is also being used in the evaluation of patients with chronic groin pain, who have no definite clinical signs of hernia. In this cohort of patients, the detection yield of this investigation alone range between 11% to 54%.4, 5 The reported sensitivity and specificity of this test in detecting occult inguinal hernia is in excess of 94%.6, 7 False positive and false negative results are 0 to 18.7% and 2 to 7.9% respectively.8 These variations reflect the fact that herniography is an operator dependent investigation and as such, is prone to error, both in the way the procedure is performed and in the interpretation of the findings.
Herniography is a safe but invasive procedure. One of the main complications is inadvertent bowel perforation.6 Two such cases were reported recently in a series of 80 herniograms performed for chronic groin pain evaluation.9 Both were identified during the procedure; one patient was treated conservatively and the second one underwent diagnostic laparoscopy but again treated conservatively. Reported complication rate in the literature varies between 1 to 5%.6
Pre-operative clinial diagnosis of spigelian hernia is difficult as they are often asymptomatic and tend to occur in obese patients. Unlike groin hernias, peritoneography does not, as yet, have an established role in detecting Spigelian hernia. Non-invasive imaging modalities like ultrasound scan (USS), computerised tomography (CT) and magnetic resonance imaging (MRI) have all been found to be effective in detecting these occult abdominal wall hernias.4 USS is a very useful and simple imaging method to demonstrate Spigelian hernia, as it has an advantage over both CT and MRI modalities in being a real-time examination. It allows the radiologist to examine the patient in standing position or to use Valsalva manoeuvre to demonstrate the hernia better.4 Similarly, herniography has the same advantage over both CT and MRI and thus can be used very effectively by an experienced radiologist. Unlike the report of Svahn and Spangen10 herniography has now been increasingly shown to be an effective diagnostic tool in detecting spigelian hernia, as demonstrated in our case. In addition it may help to pick up those occult hernias that are missed by USS, as was also shown in our patient.
Conclusion
Symptomatic spigelian hernia can be difficult to diagnose in absence of obvious clinical signs. USS remains the imaging modality of choice and if indicated, further imaging by CT or herniography should be used depending on the experience of the radiologist. Herniography is an invasive procedure but used selectively and carefully, has proved to be a very useful investigation in the detection of occult abdominal wall hernias with high sensitivity and specificity.
REFERENCES
1 Spangen, L, Spigelian hernia. Surgical Clinics of North America, 1984. 64(2): p. 351-66.
2 Gullmo ABA Smedberg S, Herniography. Surg Clin North Am, 1984. 64: p. 229-244.
3 Ducharme JC, BR, Chacar R, Is it possible to diagnose inguinal hernia by Xray? A preliminary report on herniography. Journal of the Canadian Association of Radiologists, 1967. 18: p. 448-451.
4 Toms, AP, et al, Illustrated review of new imaging techniques in the diagnosis of abdominal wall hernias. British Journal of Surgery., 1999. 86(10): p. 1243- 9.
5 Hamlin JA, KA, Herniography: a review of 333 herniograms. Am Surg, 1998. 64: p. 965-969.
6 Brierly, RD, PC Hale, and NL Bishop, Is herniography an effective and safe investigation? Journal of the Royal College of Surgeons of Edinburgh., 1999. 44(6): p. 374-7.
7 Gwanmesia, II, et al, Unexplained groin pain: safety and reliability of herniography for the diagnosis of occult hernias. Postgraduate Medical Journal., 2001. 77(906): p. 250-1.
8 Loftus IM, US, Rodgers PM et al, A negative herniogram does not exclude the presence of a hernia. Ann R Coll Surg Engl, 1997. 79: p. 372-375.
9 Heise, CP, IA Sproat, and JR Starling, Peritoneography (herniography) for detecting occult inguinal hernia in patients with inguinodynia. Annals of Surgery., 2002. 235(1): p. 140-4.
10 Svahn, T and L Spangen, Peritoneography in spigelian hernias. Acta Radiologica: Diagnosis, 1976. 1F(1): p. 97-100.