Cervical disc replacements

Introduction:

Cervical disc replacements are now being considered as an alternative to cervical fusion. The normal intervertebral disc of the cervical spine is critical for the normal movement and function of the neck. Wear and tear changes of the disc may cause a piece of disc to compress the nerve roots or alternatively formation of bony spurs may compress the nerve root leading to neck and arm pain.

Standard surgical treatment

The standard current surgical procedure is cervical fusion (hyperlink). This is a highly successful procedure with over 187,000 such procedures being undertaken per year in U.S.A. There are however some limitations of this procedure: fusing 2 adjacent vertebrae is thought to place increased stresses on the levels above and below, resulting in increased frequency of degeneration of these levels; bone graft often is be harvested from the patients iliac crest (hip region)- amongst other things (risk of haematoma, infection, local nerve damage) this can be sore.

Cervical disc replacement

The aim of disc replacement is to avoid the 2 major complications of cervical fusion, i.e. reducing the incidence of adjacent segment degeneration while maintaining normal neck movement and the elimination of donor site complications. The first cervical disc replacements (Bristol-Cummins disc) were developed in the 1980s by a British Neurosurgeon at Frenchay hospital in Bristol. This consisted of a ball and socket device they have subsequently undergone re-design and modification. Below Prestige II Disc replacement.

Case presentation

A 39year old man presented with symptoms of arm pain and was found to have a degenerate disc at level C5-6 compressing nerve roots. MRI axial below

After informed consent he underwent cervical disc replacement. Below are 2 radiographs showing the prosthesis with the neck in flexion and extension.

Do Cervical disc replacements work and are there any risks?

Current evidence suggests that patients undergoing cervical disc replacement have a good outcome based on neurological assessment and was protective against undesirable motion that is seen with fusion.

There have been reported reports of adverse events for cervical disc replacement including post-operative pain, failure of intended mobility, screw breakage and pull-out.

Summary

Cervical disc replacement is an emerging technique which promises to offer substantial benefits. Currently only a few highly trained surgeons are performing this procedure and the selection of patients for such procedures must be carefully considered. We do not yet know the long term outcomes of having an artificial disc. As with any new medical technology further studies and meticulous follow up of patients who have had this procedure will guide the profession. The National Institute for Clinical Excellence has prepared an overview on this procedure based upon review of medical literature and medical opinion. They will then look at issues such as its efficacy, safety and cost-effectiveness and give guidance about its further use throughout the NHS.