Class II limited to certain treatments; excludes cervical, pediatric use
Years of confusion about the Food and Drug Administration (FDA) classification of pedicle screws came to an end in July when the FDA issued a final rule reclassifying the devices to class II from class III for certain indications.
The final rule, published in the Federal Register July 27, 1998, states that "FDA is classifying into class II, the unclassified preamendments pedicle screw spinal systems intended for treatment of severe spondylolisthesis (grades 3 and 4) of the L5 S1 vertebra in skeletally mature patients receiving fusion by autogenous bone graft having implants attached to the lumbar and sacral spine with removal of the implants after attainment of a solid fusion.
In addition, FDA is "reclassifying into class II the postamendments class III pedicle screw spinal systems intended to provide immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the treatment of the following acute and chronic instabilities or deformities of the thoracic, lumbar and sacral spine: Degenerative spondylolisthesis with objective evidence of neurologic impairment, fracture, dislocation, scoliosis, kyphosis, spinal tumor and failed previous fusion (pseudarthrosis)."
The pedicle screw spinal systems must comply with materials standards, mechanical testing standards of performance, biocompatibility standards and labeling requirements.
The labeling contains a "warning" that the safety and effectiveness of the devices has been established only for certain spinal conditions, which are listed, and a "precaution" that "the implantation of pedicle screw spinal systems should be performed only by experienced surgeons with specific training in the use of this pedicle screw spinal system because this is a technically demanding procedure presenting a risk of serious injury to the patient."
The intent of the "precaution," FDA said, was not to specify the type of training that should be available or approve any training. It was intended to alert surgeons to the necessity of receiving appropriate training in the use of the devices.
FDA noted there were some public comments that appropriate training of surgeons should be required and that professional societies and hospitals, not FDA or the manufacturers, should determine what constitutes adequate training for surgeons implanting the devices. FDA agrees that is it important that surgeons who use the devices should have proper training, but FDA does not believe that it should identify who is most qualified to provide the training or determine what constitutes adequate training.
The final rule states that neither well-controlled investigations nor valid scientific evidence relating to pedicle screw spinal systems intended for use in the cervical spine is available, and therefore, use of the systems for the cervical spine are excluded from this classification and reclassification and are considered postamendments class III devices for which premarket approval is required. Also, the safety and efficacy of the pedicle screw spinal systems on pediatric populations have not been demonstrated. Therefore these systems for use in pediatric populations are postamendments class III devices for which premarket approval is required.
The proposed rule to classify certain unclassified preamendments pedicle screw spinal systems was published in the Federal Register Oct. 4, 1995. FDA said it received 4,060 comments, the overwhelming majority of which were in favor of the proposed rule. In response to the comments, FDA reanalyzed the meta-analysis of the literature, the Cohort study of data from 3,498 patients and publicly released Investigational Device Exemption data for the indications of spinal fractures and degenerative spondylolisthesis.