Lumbar orthosis with unilateral hip immobilization. Effect on intervertebral mobility determined by roentgen stereophotogrammetric analysis.

To determine the additional stabilizing effect of unilateral hip fixation on external lumbar supports, nine patients with a posterolateral lumbosacral fusion without internal fixation were examined by roentgen stereophotogrammetric analysis. The roentgen stereophotogrammetric analysis was performed with the patients in supine and erect positions 1 month after surgery, that is, before fusion consolidation. Each patient was examined without lumbar support and with a molded, rigid thoracolumbosacral orthosis with extension to one thigh, thus immobilizing one hip. The additional hip immobilization had no consistent or significant stabilizing effect on the sagittal, vertical, or transverse intervertebral translations in the lower lumbar spine. This study using roentgen stereophotogrammetric analysis gave no support for including hip immobilization when using lumbar orthoses after spinal fusion in patients adequately cooperating to minimize gross body motions.