Failed back syndrome.

Daniel Aghion, MD, Pradeep Chopra, MD, Adetokunbo A. Oyelese, MD, PhD  approximately 250,000 surgeries for low back pain are performed annually in the USA. Approximately 40% of patients undergoing lumbar surgery continue to report significant pain after surgery, and a significant portion of these will result in failed back syndrome (FBS). FBS is defined as persistent or recurrent chronic pain after one or more surgical procedures on the lumbosacral spine. The incidence of true FBS is as high as 15%. Unfortunately, the diagnosis of FBS does not point to the actual cause for treatment failure. Multiple factors can contribute to the development of this syndrome such as residual or recurrent disc herniation, persistent post-operative radiculopathy, joint instability, scar tissue, or muscular deconditioning. Furthermore, patients may be predisposed to FBS due to systemic disorders such as diabetes, autoimmune disease, psychiatric disease, or vascular disease. Overall, it is clear that both biological and psychological issues play a significant role in the outcome of lumbar spine surgery. The specific causes of FBS have been a topic of much debate. Patients with this syndrome can be divided into one of two groups: 1. Patients in whom surgery was never indicated, or the surgery performed carried a low likelihood of achieving the desired result. 2. Patients in whom the surgery was indicated but the surgical procedure was inadequately or incompletely performed, failing to achieve the intended result. There have been several studies that have suggested that up to 95% of FBS cases are related to inappropriate surgery on patients with myofascial pain from muscle denervation, symptoms of fibromuscular dysplasia, or quadratus lumborum, iliopsoas and gluteal muscle syndromes which may mimic the pain distribution of a herniated disc. Operative intervention in these cases would carry a low likelihood of success and as such, surgery should not be entertained in these scenarios. Furthermore, it has been generally agreed that patients with predominantly radicular pain will have better outcomes following surgery than those with predominant complaints of back pain. This is because it is usually more straightforward to identify the source of pain or “pain generator” on an MRI in the case of a pinched nerve causing radicular symptoms than it is to identify the pain generator causing low back pain. Thus, many patients with asymptomatic but abnormal appearing degenerated discs on MRI or with myofascial pain may be subjected to inappropriate lumbar surgery with resulting poor outcomes.