Goal of the study?
In this review 1, the authors have two goals:
- To determine how changes that occur to the sensory nervous system in intervertebral disc degeneration (IVDD) impact lower back pain.
- To look at potential therapeutic approaches for lower back pain (LBP).
Why are they doing this research?
Lower back pain (LBP) is a prevalent problem that causes serious discomfort and disability for individuals and can also place a significant economic and medical burden on society. While the development of LBP can be seen in individuals with many different conditions such as arthritis, trauma and infection, it is widely thought that intervertebral disc degeneration (IVDD) is the leading cause of LBP. However, there is still a lack of knowledge about the development of IVD-related LBP, particularly how changes to the sensory nervous system play a role in developing and maintaining back pain. Understanding how LBP occurs may help to enable the development of new treatment approaches for patients with LBP.
What did they find?
Role of the sensory nervous system in IVD-related lower back pain
Existing research suggests that changes to the sensory nervous system (particularly pain-transmitting pathways) play a significant role in the relationship between IVDD and LBP. Changes to these pain transmitting pathways are the result of mechanical, inflammatory and other potentially damaging triggers.
As IVDD progresses, inflammatory and sensory neuropeptides are overproduced in the IVD and further deteriorate the intervertebral disc. New nerve fibres, supported by nerve growth factor (NGF) receptors, grow into the increasingly degenerated intervertebral disc resulting in increased sensitivity and inflammation, enabling LBP development.
Disc herniation is commonly associated with IVDD. Studies show that mechanical compression on nerves from a herniated disc causes nerve swelling and can increase activation of inflammatory cells (such as glial cells) and hypersensitivity and lead to LBP. Research has shown that degenerated discs contain higher inflammatory cytokines and chemokines such as TNF (tumour necrosis factor), IL-1 (interleukin 1) that serve to inflame.
Potential therapeutic targets for LBP
Understanding how changes to the sensory nervous system plays a role in IVD-related lower back pain provides a pathway to potential treatments. To date, there are both pre-clinical (animal) and clinical studies looking at potential treatments across a range of targets. For example, some studies have looked at how to stop new nerves’ growth in the deteriorated IVD by using anti-NGF antibodies or anti-inflammatory therapies that target cytokines such as TNF or IL-1. Other studies have used animal models to look at ion channels (that help regulate nerve sensitization) as potential targets for reduced pain.
(there are two good tables that you may want to include on the studies they looked at)
Why do these findings matter?
As back pain is a prevalent problem for many people, there is a need to find non-surgical approaches to treatment. Research has demonstrated the role of the sensory nervous system in IVD related LBP. This review highlights how targeting the pathological changes of the sensory nervous system (specifically the pain pathways) has the potential for numerous treatment targets for patients and their healthcare providers.
At ddd, we create models that include disc innervation so professionals can have intelligent conversations with the low back patients they care for.