Failed Back Syndrome Daniel Aghion, MD, Pradeep Chopra, MD, Adetokunbo A
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Failed Back Syndrome Daniel Aghion, MD, Pradeep Chopra, MD, Adetokunbo A. Oyelese, MD, PhD APPROXIMATELY 250,000 SURGERIES with predominant complaints of back to significant nerve root injury (2-3%) for low back pain are performed annu- pain.3 This is because it is usually more because more retraction on the neural ally in the USA.1 Approximately 40% straightforward to identify the source of elements is necessary to gain access to of patients undergoing lumbar surgery pain or “pain generator” on an MRI in the the disc pathology. Conversely, excessive continue to report significant pain after case of a pinched nerve causing radicular bone removal as with a laminectomy, in surgery, and a significant portion of these symptoms than it is to identify the pain which a significant amount of facet joint will result in failed back syndrome (FBS). generator causing low back pain. Thus, removal is performed, may lead to spinal FBS is defined as persistent or recurrent many patients with asymptomatic but instability and pain. chronic pain after one or more surgical abnormal appearing degenerated discs FBS after a lumbar fusion can ensue procedures on the lumbosacral spine. The on MRI or with myofascial pain may be due to extensive instrumentation or fu- incidence of true FBS is as high as 15%. subjected to inappropriate lumbar surgery sion across multiple segments. This can Unfortunately, the diagnosis of FBS does with resulting poor outcomes. result in a ‘flat back syndrome’ or loss not point to the actual cause for treatment of normal lumbar lordosis leading to failure. Multiple factors can contribute to One of the most FBS. Pseudoarthrosis and non-union the development of this syndrome such (incomplete fusion; 5-35%), or hardware as residual or recurrent disc herniation, common and failure (fracture or loosening) may also persistent post-operative radiculopathy, most overlooked contribute to continued back pain and joint instability, scar tissue, or muscular FBS. Transitional or adjacent segment deconditioning. Furthermore, patients causes of FBS syndrome may also be a cause of FBS may be predisposed to FBS due to sys- is inappropriate after lumbar fusion. This is where ac- temic disorders such as diabetes, auto- celerated degenerative changes occur at immune disease, psychiatric disease, or patient selection. levels adjacent to a spinal fusion result- vascular disease. Overall, it is clear that Appropriate patient ing in instability that is characterized by both biological and psychological issues hypermobility, kyphosis or scoliosis above play a significant role in the outcome of selection is one of or below a spinal fusion segment. lumbar spine surgery. the most important One of the most common and most The specific causes of FBS have been overlooked causes of FBS is inappropri- a topic of much debate. Patients with this factors in the ate patient selection. Appropriate patient syndrome can be divided into one of two outcome of any selection is one of the most important fac- groups: 1. Patients in whom surgery was tors in the outcome of any spinal surgery. never indicated, or the surgery performed spinal surgery. In a retrospective study of patients who carried a low likelihood of achieving the had low back surgery, less than half met desired result. 2. Patients in whom the The second group of patients with the standard criteria for surgery, empha- surgery was indicated but the surgical FBS includes those for whom surgery was sizing that failure of initial surgery is not procedure was inadequately or incom- indicated but in whom incomplete or in- an indication for a second surgery. pletely performed, failing to achieve the adequate operations were performed. This Psychological, social, and behav- intended result. may happen after a standard laminectomy ioral issues play a significant role in the There have been several studies and discectomy or after a lumbar fusion. outcome of the surgery as well, since that have suggested that up to 95% of FBS after a laminectomy/discectomy may patients with chronic low back pain as FBS cases are related to inappropriate ensue due to a laminectomy being done at a result of FBS frequently have psycho- surgery on patients with myofascial pain the incorrect level, an inadequate amount logical illnesses. These psychopathologies from muscle denervation, symptoms of of bony removal, or the targeted fragment include depressive disorders, anxiety, and fibromuscular dysplasia, or quadratus of disk was not removed. Waguespack et somatization, all of which may be under- lumborum, iliopsoas and gluteal muscle al showed that the most common diag- treated. A patient’s psychopathology is syndromes which may mimic the pain nosis for FBS was residual lateral recess thought to influence the pain level and distribution of a herniated disc.2 Op- or foraminal stenosis from an inadequate outcome from aggressive spine surger- erative intervention in these cases would bony decompression.4 Discectomies or ies. In cases where there is pre-existing carry a low likelihood of success and as laminectomies done to decompress the neural damage, it is important to not such, surgery should not be entertained in central canal without addressing underly- have unrealistic expectations of a com- these scenarios. Furthermore, it has been ing lateral recess or foraminal stenosis can plete return to full premorbid condition. generally agreed that patients with pre- lead to continued radicular symptoms Patients must understand that they may dominantly radicular pain will have better and disappointing results. Additionally, continue to have some residual pain as a outcomes following surgery than those an inadequate surgical exposure can lead result of pre-existing nerve injury. Partial 391 VOLUME 95 NO. 12 DECEMBER 2012 relief from their pain can sometimes help dysfunction. Most patients should be and trials of SCS prior to final implanta- patients improve their quality of life and given the opportunity to improve with- tion has been shown to provide the best help them tolerate any residual pain. In out additional surgeries. Comprehensive results. Infection, lead migration or break- addition to pre-operative expectations, programs have demonstrated effectiveness age, CSF leak, and weakness are some of limited social support may contribute to in relieving pain, myositis, inflammation, the complications associated with these a poor outcome after spine surgery. spasm, and restoration of range of motion. devices. Success rates are on the order of Motivational problems or secondary Vigorous physical therapy and behavioral 50% improvement in 50% of patients at gain may be the source of long-term pain therapy aimed at the elimination of lo- specialized centers.7 complaints. Patients presenting with work cal mechanical issues has been shown to Spinal narcotics may be administered related low back pain tend not to show improve function and patient satisfaction. epidurally or intrathecally for pain relief in the same benefit from any of the com- While conservative measures are being the form of a permanent delivery system mon modalities of treatment as non-work implemented, specialized pain manage- such as pain pump. Morphine is the most related problems. In a prospective two ment may also offer improvement in the common analgesic agent used, though year study, patients with low back pain, functional outcome. For neuropathic other medications have been trialed in who had been off work for more than 90 pain, a series of anticonvulsants such as patients who have inadequate pain relief days from work related injuries, did not Tegretol and Neurontin have been found or adverse effects from morphine.8 FBS show any improvement from medical to be useful.6 Tricyclic antidepressants is the most common indication for pain interventions including surgery.5 Even have also proved beneficial, though may pump insertion, and anywhere from 60- when objective findings are present in a be limited by anticholinergic and central 80% of patients achieve good pain relief psychologically unstable patient or there effects.7 When pain is of somatic origin, from intrathecal drug administration.6 are compensation and litigation factors NSAID’s have been a mainstay of treat- Pump malfunction causing overdose or present, the outcome from back surgery ment. withdrawal symptoms, infection, men- is doubtful. ingitis, or respiratory failure are some of The key to evaluating a patient with The key to the complications associated with these multiple lumbar surgeries or failed back devices. surgery is to gather all the information evaluating a Additional surgery for FBS is contro- in a very organized fashion. Testing in patient with versial and several general principles must FBS patients is done to confirm a diag- be taken into account. If root compression nosis rather than to ‘fish’ for a diagnosis. multiple lumbar syndromes or instability is the cause of the A good history and focused physical surgeries or failed syndrome, those patients will respond to exam is very important, as is reviewing a second operation with almost the same of all radiological data. Seek answers to back surgery is outcomes as would have attended first questions such as pre-operative versus to gather all the surgery.9 Beyond a second operation, post-operative complaints. Knowing the however, there is usually declining efficacy duration of relief from symptoms after information in a and success rates drop to 15% after the the surgery may help determine whether very organized third and 5% after the fourth.9 Surgery there is a recurrence of a herniated disk or designed to correct anatomical abnormali- residual lateral recess stenosis. A history fashion. ties or to restore sagittal alignment and of systemic complaints such as irritability, balance (reversal of flat back syndrome) fatigue, fever and weight loss, and back Identifying the pain generator may are more likely to be successful than sim- pain as compared to leg pain should be be quite frustrating and, because of ple revision of a prior surgery.