Medial approach for drainage of the obturator musculature in children.

BACKGROUND: In a recent study designed to determine the anatomic location of infection in children presenting with acute hip pain, fever, and elevated inflammatory markers, we demonstrated the incidence of infection of the musculature surrounding the hip to be greater than twice that of septic arthritis. Importantly, the obturator musculature was infected in >60% of cases. Situated deep in the pelvis, surrounding the obturator foramen, debridement of these muscles and placement of a drain traditionally requires an extensive ilioinguinal or Pfannenstiel approach, placing significant risk to the surrounding neurovascular structures. We hypothesized that the obturator internus and externus could be successfully debrided using a limited medial approach.

METHODS: An IRB-approved prospective study of children (0 to 18 y) evaluated in the pediatric emergency department by an orthopaedic surgeon to rule out septic hip arthritis at a tertiary care children's hospital (July 1, 2010 to June 30, 2012) was conducted. Infected obturator musculature was identified and confirmed using magnetic resonance imaging. Cadaveric dissection was performed comparing the ilioinguinal, Pfannenstiel, and proposed minimally invasive medial approach. The proposed approach was utilized to debride and place drains in 7 consecutive patients.

RESULTS: Anatomic information gained from magnetic resonance images of patients with abscess within the obturator musculature, and from the results of cadaveric studies, allowed for planning of a novel surgical approach. We found that through the surgical approach used to perform an osteotomy of the ischium (Tonnis) the obturator externus could be debrided through the adductor brevis and the obturator internus could be debrided through the obturator foramen. Using our medial approach, resolution of symptoms in all children who underwent surgical drainage resulted without complication.

CONCLUSIONS: Our medial approach can safely access the obturator musculature for abscess decompression and drain placement with successful results. Advantages to this approach include: lower risk to neurovascular structures within the pelvis, less soft tissue trauma, and similarity to current techniques used for adductor lengthening, medial reduction of the dislocated hip, and osteotomy of the ischium.

LEVEL OF EVIDENCE: Level II.