Prophylaxis of the laminectomy membrane. An experimental study in dogs.

Sixty laminectomies were performed in dogs to investigate the prevention of the laminectomy membrane and its side effects. These operations were distributed in six groups of 10, one was a control group, and in the others the bone defect was protected with different materials (Oxicel, Silastic, Dacron, methyl methacrylate, and Kiel bone graft). After a survival of 2 months, suboccipital myelography was performed, immediately after which the animals were sacrificed and the operated spinal slice obtained. The different radiographic densities of the tissues of each slice were calculated and the diverse histological nature identified by hematoxylin and eosin, periodic acid Schiff, Masson's trichrome, and Gomori's reticulin strains. Only the acrylic plastic and the Kiel bone graft prevented expansion of the scar tissue inside the spinal canal and adhesions between the dura and the cicatrical overlying muscles. Therefore, the authors suggest that a solid barrier is necessary to effectively prevent the so-called "laminectomy membrane."