Restoring Segmental Biomechanics Through Nucleus Augmentation: An In Vitro Study
Matthew H Pelletier1, Charles S Cohen, Paul Ducheyne
1*Surgical & Orthopaedic Research Laboratories, Prince of Wales Hospital, Sydney, NSW, Australia†Gentis Inc., Wayne‡Department of Bioengineering University of Pennsylvania, Philadelphia, PA.
Clinical Spine Surgery
|October 22, 2013
Summary
Nucleus augmentation with an injectable polymer effectively restored biomechanics and disk height in a laboratory model of spinal degeneration. This study provides a method for evaluating nucleus augmentation devices in vitro.
Area of Science:
- Biomechanical engineering
- Spinal biomechanics
- Biomaterials
Background:
- Degenerative disc disease affects spinal biomechanics.
- Nucleus pulposus augmentation offers a less invasive alternative to fusion or total disc replacement.
- Evaluating nucleus augmentation in vitro is challenging without induced pathology.
Purpose of the Study:
- To evaluate a mechanical method for inducing spinal degeneration in vitro.
- To assess the ability of nucleus augmentation to restore biomechanics.
- To establish a model for evaluating nucleus augmentation devices.
Main Methods:
- In vitro biomechanical testing of ovine motion segments (n=6).
- Induction of degenerative changes via creep loading and nucleus disruption.
- Nucleus augmentation using an injectable polymer (DiscCell).
- Evaluation of pure moment bending and compressive biomechanics.
Main Results:
- Degenerative treatment increased neutral zone (NZ) and range of motion (ROM) in all bending modes.
- Lateral bending was most sensitive to degenerative changes.
- Nucleus augmentation with DiscCell reversed ROM and NZ changes, restoring intact biomechanics.
- Disk height was restored during time zero tests.
Conclusions:
- Injectable polymer nucleus augmentation effectively restored motion segment biomechanics.
- The study provides a valid in vitro model for evaluating nucleus augmentation technologies.
- This approach may inform the development of less invasive treatments for degenerative disc disease.
