Sciatic hernia: is it really rare?

It is generally believed that sciatic hernia is extremely rare; however, asymptomatic sciatic hernia is occasionally found in patients with an obturator hernia. We investigated the frequency, risk factors, and prognosis of asymptomatic sciatic hernia, which have never been discussed in a published report. We retrospectively reviewed multidetector-row computed tomography (MDCT) images of 38 consecutive cases of new-onset obturator hernia. The co-existence of sciatic hernia was diagnosed from the MDCT findings of some of these patients. The clinical characteristics and clinical courses were compared between the sciatic hernia group and the non-sciatic hernia group. Nine patients (24 %) had concomitant asymptomatic sciatic hernias, five (13 %) of which were bilateral. The body mass index (BMI) was significantly lower in the patients with a concomitant sciatic hernia (17.2 +/- A 2.4 kg/m(2)) than in those without a sciatic hernia (19.6 +/- A 2.6 kg/m(2); P = 0.02). All patients received treatment for incarcerated obturator hernias, but none underwent repair of the concomitant sciatic hernia because all were non-incarcerated and asymptomatic. None of the patients has had trouble with their untreated sciatic hernia after the obturator hernia treatment. Up to 24 % of these obturator hernia patients had a concomitant sciatic hernia. A low BMI was a risk factor for concomitant sciatic hernia. Immediate surgical repair of the sciatic hernia may not be needed, unless it is symptomatic.