The impact of non-invasive manual and ultrasonographic reduction for incarcerated obturator hernia: a retrospective cohort study and systematic review

Non-invasive reduction in patients with incarcerated obturator hernias is an emergency surgery alternative. There are two non-invasive reduction types: manual and ultrasonographic (ultrasound-guided and ultrasound-assisted reduction). However, the impact of ultrasound guidance on manual reduction has not been adequately evaluated. We aimed to compare non-invasive ultrasound reduction with manual reduction in patients with incarcerated obturator hernias.

We searched MEDLINE, Cochrane Central Library, Embase, Ichushi Web, ClinicalTrial.gov, and ICTRP for relevant studies. The primary outcomes were success and bowel resection rates. We performed a subgroup analysis between ultrasound-guided and ultrasound-assisted reductions. This study was registered in PROSPERO (CRD 42,024,498,295).

We included six studies (112 patients, including 12 from our cohort). The success rate was 78% (69 of 88 cases) with ultrasonographic reduction and 33% (8 of 24 cases) with manual reduction. The success rate was higher with ultrasonographic than with manual reduction. Subgroup analysis revealed no significant difference between ultrasonography-assisted (76%) and ultrasonography-guided (80%) reductions (p = 0.60). Non-invasive reductions were predominantly successful within 72 h of onset, although durations extended up to 216 h in one case. Among the successful reduction cases, emergency surgery and bowel resection were necessary in two cases after 72 h from onset. Bowel resection was required in 48% (12 of 25), where the non-invasive reduction was unsuccessful within 72 h of confirmed onset.

Ultrasonographic reduction can be a primary treatment option for patients with obturator hernias within 72 h of onset by emergency physicians and surgeons on call. Future prospective studies are needed to evaluate ultrasonographic reduction’s impact.