Clinico-Biomechanical Issues and Dynamic Stabilization When Considering Stem Cell Treatment for Degenerative Disc Disease

Abstract

After reading the article published in Transplantation (1), scientists are to be congratulated—especially with the clinical results as published. Looking for alternatives to avoid fusion is part of function-preserving spine care, as it should be the last option to be undertaken while keeping the debate open (2, 3). Nevertheless, we would like to point out some questions that arise from a clinical point of view from our daily surgical practice. First, several clinical presentations and procedures are compared without taking into account that they are different treatments applied for different disc disease situations (discectomy is performed for disc herniation with radicular symptoms, disc prosthesis is contraindicated in instability or facet joints arthritis, and so on): we should not mix apples with oranges, also the placebo effect and the natural course of the degeneration (4), particularly in this young group of patients with radiculopathy (5), with waiting-list phenomenon because of natural healing. On the other hand, probably the most important point for succeeding in spinal surgery is proper clinicoradiologic diagnosis, as low back pain may be caused by several causes, which should be ruled out: patient selection remains a key for success. We were also happy to see the clinical improvement achieved from the beginning with the approach reported. Nevertheless, a sensible explanation for the relationship between pain improvement at 3 months and water content changes only at 1 year cannot be found, as disc height remain unchanged throughout the whole study period (improvement of this parameter is not the objective in surgical procedures as fusion or TDR). Also, no pictures on disc degree of degeneration nor X-ray films helps us to determine both the possible cause of disc degeneration and possible morphologic changes after the intervention (disc height and intensity correlates with water and proteoglycan contents). If a clinical study were to be conducted in the future, we propose that a double-blind randomized study, once patients with radicular symptoms and instability on dynamic X-rays excluded, for comparison of moderate degenerative disease (6, 7), (nonresponsive to conservative treatment) treated by either SC injection, dynamic stabilization, or instrumented fusion (ALIF/360°), stratified by MRI appearance and MODIC changes to check for the benefits of this promising technique. We do not feel that it would be ethical to puncture the disc and not deliver stem cells, as discography has proved to accelerate degeneration in discs (8). Javier Melchor Duart Clemente1 Julio Vicente Duart Clemente2 1 Spinal Unit, Neurosurgical Service La Fe Hospital Valencia, Spain 2 Orthopedics Service Pamplona Hospitals Pamplona, Spain