The term ‘far lateral’ applies to prolapse of a lumbar disc which compresses the nerve root at the same level irrespective of whether it is in the intervertebral canal, at the foramen or further laterally. This usually occurs in the elderly patients as degenerative changes alter the normal characteristics of the vertebral segments. As shown in figure 1 and figure 2.
Failure to recognise its presence has often been responsible for a poor outcome and persistent sciatica after an operation. CT and MRI now allows successful demonstration of protrusions of the lateral disc.
Prolapse of a lumbar disc at this site, however, may still be overlooked.