Osteoplastic laminotomy using titanium microplates. A technique for reconstruction of the laminar roof

Introduction: There is accumulating evidence, that the anatomical reconstruction of the spinal canal is superior to the destructive procedure of laminectomy. With modern equipment it is possible to remove a multilevel laminotomy block in a few minutes, but the reconstructive part of the procedure is still time consuming and optimal realignement of the laminae is sometimes difficult to achieve. To overcome these problems we used titanium microplates for the reconstruction of the posterior elements of the spinal canal. Our experience with this technique in twenty-one patients is reported. Operative Technique: A dorsal midline approach to the spine was used. The osteotomy of the laminae was performed in a standard fashion using a high-speed drill. After finishing the intraspinal surgery the laminotomy bloc was prepared for reconstruction. In a first step a microplate was secured to each lamina on each side with one bone screw. The laminar roof was then replaced. The plates were adjusted and bent to achieve optimal realignement of the laminar cut ends. In a second step first the most rostral then the most caudal lamina were fixed to the lateral pedicles bilaterally and all bone screws were inserted in these two segments. Then the laminae of all other segments were carefully repositioned and secured with plates and screws. As some bony defect results from the cut line of the drill, the laminae were positioned so, that either the left or right side alternating from one segment to the next was flush with the cut edge at the pedicle. The remainder of the closure was done in a routine fashion. Results: Twenty-one patients underwent osteoplastic laminotomy. Eleven operations were performed in the cervico-thoracic, 5 in thoracic and 5 in the patient. 19 patients were operated on for intraspinal tumors and 2 patients for intradural cysts. The mean age of the patients was 30 years, ranging from 3 to 71 years. There was no operative morbidity related to the procedure of osteoplastic laminotomy. In 13 patients magnetic resonance tomography (MRT) of the spine was performed postoperatively. In all cases adequate evaluation of the intraspinal anatomy was possible. Fourteen patients had follow-up examinations at least 6 months postoperatively. No problems related to the laminotomy procedure were encountered. Plain radiography demonstrated correct position of the laminae, and no significant malalignement of the spine was observed in these patients. Discussion: The use of titanium microplates greatly facilitates the reconstruction of the laminar roof following laminotomy. The advantages of this technique are: a) the procedure is time-sparing compared to conventional techniques, b) unilateral fixation of the lamina is possible in cases where the pedicle of the vertebra is completely removed on one side for a more lateral approach to the spinal canal, c) immediate considerable rigidity is achieved with microplate fixation, so that the risk of migration of the laminar flap into the spinal canal is minimized. In our experience the procedure is safe and no adverse effects were observed. Furthermore the titanium implants are fully compatible with postoperative MRT.