Psoas over the brim lengthenings. Anatomic investigation and surgical technique.

Lengthening of the psoas tendon commonly is performed for various conditions of the hip including developmental dysplasia and neuromuscular contractures and instability. Anecdotal reports of injury to surrounding neurovascular structures suggest an investigation of the local anatomy is warranted. Using magnetic resonance images from 54 children younger than 10 years, the authors examined the anatomic relationship between major neurovascular structures (femoral artery and vein, external iliac artery and vein, femoral nerve) and the psoas tendon. The mean distance between the neurovascular structures and the psoas tendon in the over the brim position is 1 cm, although it may be as close as 4 mm in a child. The mean distance is 3.1 cm at the tendon's insertion at the lesser trochanter. Surgeons performing psoas over the brim lengthenings should be aware that major neurovascular structures may be only 4 mm from the psoas tendon. The recommended surgical technique is presented.