Shortening of a unit rod protruding into the hip joint: case report and description of a surgical technique.

A unit rod is a well-accepted method of posterior spinal instrumentation in patients with cerebral palsy (CP). Several types of complications after the use of a unit rod were reported, including penetration through the medial wall of the pelvis. A patient who underwent anterior and posterior spinal fusion with unit-rod instrumentation was found to have penetration of the unit rod into a dysplastic hip joint. The pelvic limb of the rod was shortened with a burr through an anterolateral approach to the iliac bone. This procedure was associated with a lower blood loss than was previously reported for revisions of unit rods. There was no need for hardware removal and therefore no loss of correction. The unit rod may be shortened before surgery to prevent this problem. The described procedure is a simple way of correcting penetration of a unit-rod limb into the hip joint.