New laminoplasty after thoracic and lumbar laminectomy.

We report the development of a new laminoplasty for the thoracic and lumbar spine. In this method, after two or three laminae are subjected to en bloc laminectomy using a surgical air drill, median longitudinal incisions are made in the laminae from the ventral side with a microsurgical saw and then the resected laminae are put back in place, like pitching a tent. Because fixation is accomplished with silk thread, magnetic resonance imaging is unaffected. In 39 cases in which this method was used, the spinal canal was adequately enlarged and bony union was also satisfactory starting after a mean of 4.3 months. This method is useful as a form of anatomical repair after laminectomy. Because it preserves the posterior element, it helps to prevent shrinkage of the laminectomy membrane mass and postoperative spinal column deformity.