Performed by – Sri Chatakondu, Mark Thomas, Adam Way

What is interspinous stabilisation?
This is a procedure that is carried out as an adjunct to a lumbar spinal decompression or discectomy. Sometimes the surgeon may feel that there is an element of instability associated with the degeneration causing spinal stenosis. In this circumstance the patient might complain of significant back pain as well as leg pain. There may also be a concern that the narrowing around the nerves may recur at a later date as the disc degenerates further. A further concern may be that a very large disc prolapse will lead to significant back pain in the future despite successful initial surgery.

One way to tackle this excessive motion would be by performing a spinal fusion. This is often a much more involved procedure than a straight forward decompression or discectomy and with a higher rate of complications and a slower recovery. As the incidence of the problems highlighted above is low; it would be unreasonable to perform a spinal fusion in everyone at the outset.

A variety of implants have been designed to try and achieve a middle ground. They are simple to put in and do not require much more muscle dissection than a straightforward decompression. The recovery from this operation is therefore about the same as are the risks.

The commonest devices are the COFLEX, WALLIS LIGAMENT and DIAM.

They all sit in the interspinous space but have different attachment methods and characteristics.

Some interspinous devices (Wallis and DIAM) seek to constrain the vertebrae both in flexion (leaning forward) and extension (leaning backward) whereas others just seek to prevent over-extension (Coflex).

What are the advantages?
All of these devices are simple to put in and do not require much more tissue damage than the primary procedure. The recovery and risks are therefore similar to the primary procedure. If the device is successful in preventing future problems then a much more complex operation will have been avoided.

Another advantage of these implants is that they do not interefere with the ability to perform a more complex procedure at a later date should this be necessary.

What are the disadvantages?
The advantages are theoretical. In theory these devices should provide some extra stability to the decompressed lumbar spine level and laboratory studies on models would support this. However, to prove an effect in actual patients is much more difficult as no two patients are the same. In the absence of randomised clinical trials these devices must be regarded as experimental.

What are the risks?
The risks are the same as for the index procedure (lumbar decompression or discectomy) but in particular.

Infection: whenever a foreign material is inserted into the body the risk of infection is raised. This is still a low risk.

Dislodgement of prosthesis: As with any implant the device can become dislodged or loose. This may cause pain. A particular possibility with interspinous devices is fracture of the spinous process. This seems to be rare with the devices mentioned above.

Questions?
This document is intended to cover the most significant risks and commonly asked questions. If you have any further questions then please contact your surgeon’s secretary.