failed back syndrome failed back syndrome failed back syndrome or post-laminectomy syndrome is a condition characterized by chronic pain following back surgeries. many factors can contribute to the onset or development of fbs, including residual or recurrent spinal disc herniation, persistent post-operative pressure on a spinal nerve, altered joint mobility, joint hypermobility with instability, scar tissue (fibrosis), depression, anxiety, sleeplessness, spinal muscular deconditioning and even cutibacterium acnes infection. an individual may be predisposed to the development of fbs due to systemic disorders such as diabetes, autoimmune disease and peripheral blood vessels (vascular) disease. failed back syndromespecialtyneurosurgery common symptoms associated with fbs include diffuse, dull and aching pain involving the back or legs. abnormal sensibility may include sharp, pricking, and stabbing pain in the extremities. the term "post-laminectomy syndrome" is used by some doctors to indicate the same condition as failed back syndrome. the treatments of post-laminectomy syndrome include physical therapy, microcurrent electrical neuromuscular stimulator, minor nerve blocks, transcutaneous electrical nerve stimulation (tens), behavioral medicine, non-steroidal anti-inflammatory (nsaid) medications, membrane stabilizers, antidepressants, spinal cord stimulation, and intrathecal morphine pump. use of epidural steroid injections may be minimally helpful in some cases. the targeted anatomic use of a potent anti-inflammatory anti-tnf therapeutics is being investigated. the number of spinal surgeries varies around the world. the united states and the netherlands report the highest number of spinal surgeries, while the united kingdom and sweden report the fewest. recently, there have been calls for more aggressive surgical treatment in europe. success rates of spinal surgery vary for many reasons. signs and symptoms cause spinal surgeons operating on a patient's back. patients who have undergone one or more operations on the lumbar spine and continue to experience pain afterward can be divided into two groups. the first group comprise those in whom surgery was not actually indicated or the surgery performed was not likely to achieve the desired result, and those in whom surgery was indicated but which technically did not achieve the intended result. patients whose pain complaints are of a radicular nature have a better chance for a good outcome than those whose pain complaints are limited to pain in the back. the second group includes patients who had incomplete or inadequate operations. lumbar spinal stenosis may be overlooked, especially when it is associated with disc protrusion or herniation. removal of a disc, while not addressing the underlying presence of stenosis, can lead to disappointing results. occasionally operating on the wrong level occurs, as does failure to recognize an extruded or sequestered disc fragment. inadequate or inappropriate surgical exposure can lead to other problems in not getting to the underlying pathology. hakelius reported a 3% incidence of serious nerve root damage. in 1992, turner et al. published a survey of 74 journal articles which reported the results after decompression for spinal stenosis. good to excellent results were on average reported by 64% of the patients. there was, however, a wide variation in outcomes reported. there was a better result in patients who had a degenerative spondylolisthesis. a similarly designed study by mardjekto et al. found that a concomitant spinal arthrodesis (fusion) had a greater success rate. herron and trippi evaluated 24 patients, all with degenerative spondylolisthesis treated with laminectomy alone. at follow-up varying between 18 and 71 months after surgery, 20 out of the 24 patients reported a good result. epstein reported on 290 patients treated over a 25-year period. excellent results were obtained in 69% and good results in 13%. these optimistic reports do not correlate with "return to competitive employment" rates, which for the most part are dismal in most spinal surgery series. in the past two decades there has been a dramatic increase in fusion surgery in the u.s.: in 2001 over 122,000 lumbar fusions were performed, a 22% increase from 1990 in fusions per 100,000 population, increasing to an estimate of 250,000 in 2003, and 500,000 in 2006. in 2003, the national bill for the hardware for fusion alone was estimated to have soared to $2.5 billion a year. for patients with continued pain after surgery which is not due to the above complications or conditions, interventional pain physicians speak of the need to identify the "pain generator" i.e. the anatomical structure responsible for the patient's pain. to be effective, the surgeon must operate on the correct anatomic structure, but is often not possible to determine the source of the pain. the reason for this is that many patients with chronic pain often have disc bulges at multiple spinal levels and the physical examination and imaging studies are unable to pinpoint the source of pain. in addition, spinal fusion itself, particularly if more than one spinal level is operated on, may result in "adjacent segment degeneration". this is thought to occur because the fused segments may result in increased torsional and stress forces being transmitted to the intervertebral discs located above and below the fused vertebrae. this pathology is one reason behind the development of artificial discs as a possible alternative to fusion surgery. but fusion surgeons argue that spinal fusion is more time-tested, and artificial discs contain metal hardware that is unlikely to last as long as biological material without shattering and leaving metal fragments in the spinal canal. these represent different schools of thought. (see discussion on disc replacement infra.) another highly relevant consideration is the increasing recognition of the importance of "chemical radiculitis" in the generation of back pain. a primary focus of surgery is to remove "pressure" or reduce mechanical compression on a neural element: either the spinal cord, or a nerve root. but it is increasingly recognized that back pain, rather than being solely due to compression, may instead entirely be due to chemical inflammation of the nerve root. it has been known for several decades that disc herniations result in a massive inflammation of the associated nerve root. in the past five years increasing evidence has pointed to a specific inflammatory mediator of this pain. this inflammatory molecule, called tumor necrosis factor-alpha (tnf), is released not only by the herniated or protruding disc, but also in cases of disc tear (annular tear), by facet joints, and in spinal stenosis. in addition to causing pain and inflammation, tnf may also contribute to disc degeneration. if the cause of the pain is not compression, but rather is inflammation mediated by tnf, then this may well explain why surgery might not relieve the pain, and might even exacerbate it, resulting in fbss. role of sacroiliac joint (sij) in lower back pain (lbp) a 2005 review by cohen concluded,'the si joint is a real yet underappreciated pain generator in an estimated 15% to 25% of patients with axial lbp'. studies by ha, et al., show that the incidence of si joint degeneration in post-lumbar fusion surgery is 75% at 5 years post-surgery, based on imaging. studies by depalma and liliang, et al., demonstrate that 40–61% of post-lumbar fusion patients were symptomatic for si joint dysfunction based on diagnostic blocks. smoking ct scan showing markedly thickened ligamentum flavum (yellow ligament) causing spinal stenosis in the lumbar spine. recent studies have shown that cigarette smokers will routinely fail all spinal surgery, if the goal of that surgery is the decrease of pain and impairment. many surgeons consider smoking to be an absolute contraindication to spinal surgery. nicotine appears to interfere with bone metabolism through induced calcitonin resistance and decreased osteoblastic function. it may also restrict small blood vessel diameter leading to increased scar formation. there is an association between cigarette smoking, back pain and chronic pain syndromes of all types. in a report of 426 spinal surgery patients in denmark, smoking was shown to have a negative effect on fusion and overall patient satisfaction, but no measurable influence on the functional outcome. there is a validation of the hypothetical assumption that postoperative smoking cessation helps to reverse the impact of cigarette smoking on outcome after spinal fusion. if patients cease cigarette smoking in the immediate post operative period, there is a positive impact on success. regular smoking in adolescence was associated with low back pain in young adults. pack-years of smoking showed an exposure-response relationship among girls. a recent study suggested that cigarette smoking adversely affects serum hydrocodone levels. prescribing physicians should be aware that in some cigarette smokers, serum hydrocodone levels might not be detectable. in a study from denmark reviewing many reports in the literature, it was concluded that smoking should be considered a weak risk indicator and not a cause of low back pain. in a multitude of epidemiologic studies, an association between smoking and low back pain has been reported, but variations in approach and study results make this literature difficult to reconcile. in a massive study of 3482 patients undergoing lumbar spine surgery from the national spine network, comorbidities of (1) smoking, (2) compensation, (3) self reported poor overall health and (4) pre-existing psychological factors were predictive in a high risk of failure. followup was carried out at 3 months and one year after surgery. pre-operative depressive disorders tended not to do well. smoking has been shown to increase the incidence of post operative infection as well as decrease fusion rates. one study showed 90% of post operative infections occurred in smokers, as well as myonecrosis (muscle destruction) around the wound. pathology before the advent of ct scanning, the pathology in failed back syndrome was difficult to understand. computerized tomography in conjunction with metrizamide myelography in the late 1960s and 1970s allowed direct observation of the mechanisms involved in post operative failures. six distinct pathologic conditions were identified: recurrent or persistent disc herniation spinal stenosis post operative infection epidural post-operative fibrosis adhesive arachnoiditis nerve injury recurrent or persistent disc herniation ct scan image of large herniated disc in the lumbar spine. removal of a disc at one level can lead to disc herniation at a different level at a later time. even the most complete surgical excision of the disc still leaves 30–40% of the disc, which cannot be safely removed. this retained disc can re-herniate sometime after surgery. virtually every major structure in the abdomen and the posterior retroperitoneal space has been injured, at some point, by removing discs using posterior laminectomy/discectomy surgical procedures. the most prominent of these is a laceration of the left internal iliac vein, which lies in close proximity to the anterior portion of the disc. in some studies, recurrent pain in the same radicular pattern or a different pattern can be as high as 50% after disc surgery. many observers have noted that the most common cause of a failed back syndrome is caused from recurrent disc herniation at the same level originally operated. a rapid removal in a second surgery can be curative. the clinical picture of a recurrent disc herniation usually involves a significant pain-free interval. however, physical findings may be lacking, and a good history is necessary. the time period for the emergence of new symptoms can be short or long. diagnostic signs such as the straight leg raise test may be negative even if real pathology is present. the presence of a positive myelogram may represent a new disc herniation, but can also be indicative of a post operative scarring situation simply mimicking a new disc. newer mri imaging techniques have clarified this dilemma somewhat. conversely, a recurrent disc can be difficult to detect in the presence of post op scarring. myelography is inadequate to completely evaluate the patient for recurrent disc disease, and ct or mri scanning is necessary. measurement of tissue density can be helpful. even though the complications of laminectomy for disc herniation can be significant, a recent series of studies involving thousands of patients published under auspices of dartmouth medical school concluded at four-year follow-up that those who underwent surgery for a lumbar disc herniation achieved greater improvement than nonoperatively treated patients in all primary and secondary outcomes except work status. spinal stenosis ct scan of laminectomy showing scar formation (highlighted in red)causing new stenosis. spinal stenosis can be a late complication after laminectomy for disc herniation or when surgery was performed for the primary pathologic condition of spinal stenosis. in the maine study, among patients with lumbar spinal stenosis completing 8- to 10-year follow-up, low back pain relief, predominant symptom improvement, and satisfaction with the current state