An L4 radiculopathy, the signs of which were explained in a previous blog, is a much less common finding. It is due to a HNP at L3/4, which occurs much less frequently than HNPs at either L4/5 or L5/1, where 85-90% of lumbar disc herniations occur..
Because the L4 root exits at L4/5, a far-lateral disc herniation at L4/5 could compress it, but it’s most often compressed as it crosses an L4/5 herniated disc. Similarly, a far-lateral HNP at L4/5 could get the exiting L5 root and spare the transiting S1 root. That is what makes an imaging study to valuable – not only to rule in or out HNP, but show its location for possible surgical treatment.
What are the expected outcomes of lumbar disc surgery? I will show a table of surgical outcomes in a forthcoming blog.