A study 1 in the European Spine Journal created a disc-loading simulator to help collect data about disc herniation and injury. It offered some interesting results about how lifting heavy weights and maintaining extreme postures are linked to disc weakness and damage.

What Was the Context?

The human body depends on the spinal column for trunk flexibility. While certain age-related processes are typical for a spinal column to go through, a number of disorders can give rise to health issues. These disorders include DDD or degenerative disc disease and disc prolapse.

According to present data, the prevalence of a disc prolapse tends to increase with age. It is deemed to be the highest in the age group of 30-60 years. The lower lumbar or lumbosacral spine has the highest incidence of prolapse. Research shares that the said region experiences high biomechanical loads which have a link to the development of disc prolapse. 

Take note; there’s still debate about if DDD plays a role in disc herniation or protects against it. Is disc herniation and DDD even related?

Lifting heavy weights or maintaining extreme postures are assumed to cause minor injuries in the inner annulus. The impact of such injuries tends to accumulate with time and can lead to the failure of the intact lamellae after a single loading event. There’s also an assumption that failure could begin from the outside, specifically close to the endplate.

The current team decided to create a dynamic disc-loading simulator to give rise to such failures. The objective was to better understand disc herniation and damage.

What Was the Methodology?

The general set-up of the simulator shared similarities with conventional testing devices. The machine’s dimensions, in mm, came in at 1135 (width), 735 (length), and 1655 (height). It weighed around 200 kg.

A total of 8 ovine lumbar motion segments were collected from 5 healthy sheep. The sheep were in the range of 3-5 years of age. A compressive load of 130 N was applied for a total of 15 minutes to precondition the specimen. These parameters simulated the typical spinal load experienced by a standing sheep. Testing was done by simulating dynamic activities.

An MRI system meant for animals was used for imaging of any potential defects. The Avizo standard v5.6 software was used for segmentation as well as 3D-construction of the disc along with the lesion volume.

What Was Concluded?

The results showed that typical failure patterns, as well as herniations, could be provoked by using complex asymmetrical loading protocols. Herniated discs were observed to have a link to loading with axial compression, flexion, lateral bending and torsion. Take note, all of the failures happened in the disc’s posterior region.

With the current results, the research team hoped it could help with obtaining a better understanding of how various loading conditions lead to disc failures at microstructural levels. Also, ultra-high field MRI could be used for investigating the lesion’s gradual development.

Such knowledge could help prevent spinal injuries and assist with making the public more aware of the damage that could be caused by lifting heavy weights and not maintaining proper posture.