[History of internal fixators. The subsequent importance for spinal surgery].

Background: This article presents a retrospective look at spinal implants of the 1970s and 1980s.

Objective: The historical development of internal fixators as the successor to external fixators.

Mechanical Principle: Pedicled screws are stably anchored in vertebral bodies of the thoracic or lumbar spine or the sacrum using a dorsal approach. They are joined by a rod as a longitudinal support, separated by freely selectable distances and in any desirable and initially modifiable angle. After locking this results in an angular and rotationally stable completely sunken bilateral construction for fixing two or more vertebrae together and the position can be manually adjusted using long lever arms on the pedicled screws.

Results: The first in vivo application in humans was on 22 December 1982 in Basel. The initial indications were unstable spinal fractures. The expectations placed on the new working principle of internal fixation and its realization were confirmed and short stretch fixation exclusively of the neighboring vertebra and immediate mobilization of patients could be routinely achieved. The indications were extended to include instability of the spine for conditions outside the field of traumatology. Further developments of implants and other technical solutions in the coupling system using the same basic principle in the direction of multisegmental applications, ease of operation and titanium-based materials became internationally established and were developed into universal spinal stabilization systems for spinal degeneration, deformities, tumors and olisthesis.

Conclusion: The basic principle of spinal fixators (internal and external) is contained in the complete product range of dorsal stabilizing implants from practically all manufacturers worldwide and has become taken for granted.