Lumbosciatica is a very prevalent pathology. When conservative treatments fail, surgery should be considered. The traditional surgical treatment is lumbar arthrodesis. The vast majority of patients who undergo spinal fusion cannot return to their same job and a good number of them never work again. Another form of treatment for lumbosciatica is the implantation of a lumbar disc prosthesis. This technique preserves the mobility of the lumbar area that has been operated on. This allows for a greater return to work and a higher percentage of those who return to the same job. This study aims to quantify how many of the patients who have had a lumbar disc prosthesis implanted in the last twenty years have returned to their same job, how many have had to change their jobs, and how many have not returned to work and are now totally or completely disabled from work.

Low back pain is one of the most prevalent pathologies in the world population and one of the most frequent causes of temporary and permanent work incapacity, particularly in today's largely sedentary society.

Although its etiology is broad, degenerative disc disease, herniated disc, and osteoarthritis of the facet joints are its most common causes.

Conservative treatments resolve many cases, but when they are not effective, surgical options must be considered. These can be classified into two groups: those involving vertebral fusion with loss of mobility at the level or levels in question and those attempting to preserve it.

In lumbar disc herniation, the classic treatment, discectomy, consists of more or less completely removing the nucleus pulposus through a relatively small posterior annulotomy. This causes a loss of height of the intervertebral disc and the foramina and overload of the articular facets, which over time can be accompanied by arthritic changes and trigger chronic lumbar pain.

In the degeneration of the intervertebral disc and the osteoarthritis of the articular facets, the traditional surgical technique is the arthrodesis of the vertebral segment or segments causing the symptoms. The immobilization of the painful spinal area limits the progression of the foraminal stenosis and the overload of the articular facets of the level or levels operated on. However, the fusion alters the biomechanics of the spine, causing the overload of the adjacent vertebral segments with degeneration and osteoarthritis of these, which is the cause of chronic pain. It is not uncommon that, over the years, reintervention is required to extend the arthrodesis. In turn, a larger area of fused spine will cause more overload of the adjacent levels, which will also suffer the same process of degeneration and arthrosis mentioned above, thus creating a vicious circle.

The initial step of fusion of the painful joint has also been followed in the spine in the attempt to preserve mobility by implanting a complete prosthesis of the intervertebral disc, provided that there is no degeneration or arthrosis of the articular facets. It is an option to consider compared to arthrodesis of the same segment with the appropriate surgical technique (posterolateral arthrodesis, PLIF, TLIF, X-LIF, ALIF, OLIF, 360º lumbar arthrodesis, etc.).

Studies comparing lumbar arthrodesis and arthroplasty indicate that complete lumbar disc prostheses provide a better quality of life, better control of lumbar and radicular pain symptoms, an earlier return to work, a lower incidence of adjacent level syndromes, and a lower number of complications and reinterventions. These differences are most noticeable during the first year after surgery, disappear after two years, and reappear after five years, due to the appearance of adjacent level syndrome. However, we have been able to find in the scientific literature after a thorough search which of the two surgical techniques, arthrodesis or arthroplasty at the lumbar level, achieves a greater return to the same job, or even if there are differences in terms of the work activity that each of the two surgical techniques allows. The objective of the present study is to first analyze in patients with complete lumbar disc prosthesis the percentage of return to the same job, of work activity even if it is in another job, if there is a change of work activity to what type it is changed and finally the percentage of patients who are left with work disability, of what kind and with what degree of disability. To compare with lumbar arthrodesis is not possible at this time because the arthrodesis technique, unlike arthroplasty, is very variable according to the surgeons on the team, and in our Institution, it is not possible to obtain retrospectively a homogeneous group with which to compare.

Inclusion Criteria:

• Age over 18 years with symptomatic lumbar degenerative disc herniation and/or lumbar disc herniation.

Exclusion Criteria:

• Any patient who BEFORE the implantation of a complete lumbar disc prosthesis had undergone any other type of surgical intervention on the lumbar spine. In particular, patients who had previously undergone a discectomy, whatever its form, or a spinal arthrodesis, whatever its technique, will be excluded from the study.

Patients with symptomatic lumbar degenerative disc herniation and/or lumbar disc herniation that underwent a total lumbar disc replacement