Spine Biomechanics

Chronic low back pain is a significant public health problem in industrialized society. The intact spine carries the upper body and external loads, allows motion in a physiological range and protects the spinal cord. These different demands necessitate a high degree of complexity with various sources for disorders and pain. The Julius Wolff Institute conducts research in order to counter pain causes and to further optimize the pain treatment.

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Mechanobiology for Spinal Fusion

Research on the mechanical regulation of lumbar spinal fusion

The degeneration of the intervertebral disc is one of the most common causes of specific lower back pain. Due to multiple reasons, degeneration can lead to segmental instability. Anterior inter-corporeal spinal fusion is currently the most effective surgical treatment to correct segmental instability. In most cases, a spinal cage in combination with autogenous cancellous bone is used to achieve a permanent bony fusion of one or more vertebral segments. One of the most common complications of spinal fusion is nonunion, often due to so-called "stress shielding". Thereby, the insertion of a rigid implant causes a reduction in the mechanical stimulus required for bone formation in the fusion region. This can result in early implant failure, loss of stability or malposition of the implant and pain; associated with considerable health risks and the necessity for re-operation.

The process of bone formation during inter-corporeal spinal fusion is poorly understood. Therefore, the main goal of our research in this area is to investigate the mechanical regulation of lumbar spinal fusion following spondylodesis. For this purpose, finite element models of lumbar motion segments will be developed, that incorporate the mechanical and biological factors influencing the fusion process. This knowledge will allow us to identify factors contributing to delayed healing or nonunions in some patients.

In addition, cages will be designed and optimized for the lumbar spine, which will significantly enhance skeletal fixation and reduce the time required for complete bony fusion compared to clinically available implants. This should reduce the risk of non-unions and revision surgeries as well as the associated health care costs.

Cage-Design with Small Ring Diameter
Cage-Design with Large Ring Diameter
Cage-Design with Trapezoidal Cross-Section
Cage-Design with two T-Sections