Dynamic Stabilisation

 

About dynamic stabilisation

Before reading this section, it is important to understand the treatment options for low back pain. I advice reading the page ‘Low Back Pain‘ first.

The idea behind dynamic stabilisation is to reduce the amount of pressure on painful structures inthe back or dampen down painful movement. The devices act as a form of  ‘shock absorber’. In contrast to a fusion these devices still allow some movement. There are  different devices on the market and the National Institute for Clinical Excellence in the UK (NICE) has issued guidelines for the use of these implants.  (www.nice.org.uk/nicemedia/pdf/word/IPG183publicinfoword.doc)                                                                                                                                                                                                                                                                                                                                                                                                                 

Types of implants

Dynesis (Zimmer spine Inc.)

This product has been on the market for over ten years. In priciple screws are inserted into the pedicles of the vertebra (see ‘The normal structure of the spine’) above and below the effected disc (four screws in total for one effected level). These are connected with flexible ‘cables’, which act as a shock absorber. The surgical approach is done through small incisions on either side of the midline of the spine. A transmuscular (‘Wiltse’) approach is used to insert the screws and cables. Although the muscles are split in order to insert the device, the muscle damage is minimal. The device can be used at multiple segements although and type of dynamic implant for more than 2 levels should be an exeption.

The device can also be used in connection with a spinal fusion. If a level is being fused and the surgeon is worried that the level above or below is already worn out to some degree and might suffer further (adjacent level disease – see lumbar fusion) the dynesis system can be connected to the fusion device (Dynesis DTO).

Percudyn (Interventional spine Inc)

This is a so-called facet augmentation device which has been on the market for a few years. A screw is inserted into the pedicle and connected to a stabiliser which sits under the facet joint and dampens the movement. It is true minimal invasive device, which is inserted percutanously through a small incision (1.5cm). see also Percudyn under ‘Operations’

Advantages

Dynamic stabilisation devices keep the spine moving and do not require removal of the intervertebral disc. This means that the devive can be removed if the symptoms do not improve without any future implications. Many patients hesitate to have an operation which involves removal of bone or the disc, which is necessary for a lumbar fusion or disc replacement.

Disadvantages

There is a risk that because of the continouing movement of the spine it will remain painful and the symptoms do not improve. It is also unclear for how long the devices will control the pain. It is well possible that patients require further surgery in the form of a fusion at a later stage. There is also insufficient evidence from the literatutre to see the long term benefits.

L4/5 Percudyn (left), L5/S1 Dynesis (right)

L4/5 Percudyn (left), L5/S1 Dynesis (right)