Back Surgery That Does Not Relieve Pain
In 2004, Gatchel, Miller and Lou 1 published a review of failed back surgery syndrome (FBSS) in Practical Pain Management. While the Editor’s Note preceding this article notes that FBSS is not an optimal term to use, it will be used herein due to the lack of a better term at this point. The purpose of the present article is to update that earlier review, as well as comment on any advances made in the more effective management of FBSS. The prevalence of FBSS has remained high and effective assessment/treatment protocols for its prevention and management have not yet been consistently embraced by the surgical community.
As a preamble, it is important to begin by understanding the epidemiology of acute and chronic low back pain. Acute and chronic low back pain are an increasing public health problem across industrialized nations. In the United States, 85% of people will experience an episode of low back pain at some point in their lives. 2 According to the National Health Interview Survey, 28% of adults report experiencing low back pain within the last three months. 3 A recent survey also found that the prevalence of chronic low back pain (CLBP) in North Carolina has risen substantially over a 14-year period, with 10.2% now reporting chronic, impairing low back pain. 4 Low back pain results in 31 million office visits 5 and 2.6 million emergency room visits 6 each year. LBP is also the second most common pain condition causing lost time from work. 7 Low back pain has serious economic implications as well. From 1997 to 2005, the total national expenditures for treating adults with spinal disorders increased by an inflation-adjusted 65%. 8 When both medical costs and loss of productivity are considered, back and neck pain have the highest total costs to employers of any medical condition. 9 In 2007, a total of $30.3 billion was spent on treatments for back pain. 10 Despite the increase in healthcare spending for spinal disorders, there has been little improvement in health status, functional ability, work ability, or social functioning of patients suffering from spinal disorders. 8
Most patients with low back pain recover quickly. Thirty-five percent of patients can be expected to recover within one month, 85% recover within three months, and 95% recover within six months. 2 However, those patients whose pain persists past the normal healing time are likely to develop the disabling physical and psychosocial symptoms that accompany chronic pain syndromes. These patients endure a cycle of pain that is detrimental to their physical and psychosocial health, lifestyle, and productivity. Back and spine problems were the reported cause of disability in over 10 million Americans between the ages of 21 and 64. 11 Moreover, according to the Healthcare Cost and Utilization project, there were over 633,000 hospital admissions for low back disorders and 350,000 spinal fusion surgeries in 2007 alone. 12
Many of the most chronic back pain patients do not achieve the pain relief they desire from non-operative care. These patients often then present as surgical candidates. Annually, neurosurgeons perform at least 100,000 operations for lumbar disc disease alone and orthopedic surgeons perform a similar number. 13 However, despite many positive outcomes to low back surgery, lumbar spine fusion surgery has drawn special attention over concerns about efficacy, adverse outcomes in the Workers’ Compensation setting and lack of clear surgical indications. 14-16 Indeed, many patients with FBSS will subsequently undergo additional non-operative care, and further surgery to try to correct the failed procedure. However, rates of surgical success fall off with each additional operation: only 30% of second spine surgeries, 15% of third surgeries, and 5% of fourth surgeries are successful. 17 Other patients will receive additional procedures to attempt to alleviate their continuing pain including spinal cord stimulators or implanted drug infusion devices. As many as 4,000 patients receive implanted spinal cord stimulators annually as a treatment for FBSS. 18 Still others with FBSS will be treated at chronic pain centers. Patients with FBSS present a more complicated clinical case than patients with un-operated CLBP. Interdisciplinary rehabilitation programs offer many treatment modalities based on a biopsychosocial treatment model including medication management, counseling, physical and occupational therapy, stress management and relaxation training, and psychiatric care. However, such comprehensive treatment is often not being made available to these patients because of managed healthcare insurance policies. 19,20
Indications for Spinal Surgery
Surgery is an important option for managing CLBP but it should also be viewed as a “last resort” option. Unless delaying surgery leads to permanent damage, it should only be considered after less invasive treatment options have been attempted. In fact, the Occupational Disability Guidelines published by the Work Loss Data Institute recommend that spinal fusion not be used within the first six months after diagnosis except for fractures, dislocations or in cases of severe neurological loss; while discectomy is recommended only for carefully selected patient groups. 21 If non-operative treatments are ineffectual in improving the patient’s CLBP, then surgery might be beneficial. The most common conditions for which surgery is recommended are disc bulge, disc stenosis, spondylosis, spondylolisthesis, and FBSS.
Disc Pathologies (Bulges, Herniation, Disruption)
Spinal disc degeneration occurs naturally with aging. The nucleus pulposus loses some of its gel-like consistency due to lowered water and proteoglycan content. 22 The disc may sag, and the nucleus pulposus may push against the annulus fibrosus (the wall that surrounds the disc material) causing a disc bulge. Patients with disc bulges are usually asymptomatic. 23 A disc bulge is only problematic when it is concomitant with a narrow spinal canal, leading to spinal nerve compression. Disc degeneration is influenced by mechanical load, genetic predisposition, and nutrition. 24
Disc herniations occur when the nucleus pulposus protrudes against the annulus wall to such a degree that it compresses nerve roots. If the nucleus material remains within the disc, it is called a “contained herniation.” In some cases of contained herniation, nuclear tissue travels through tears in the degraded inner annulus until it reaches the intact annulus outer wall. This can cause pain because the intact outer wall of the annulus contains pain receptors. In addition, the nucleus material contains cytotoxic agents that can cause chemical irritation and inflammation. 25 A more severe form of a herniation occurs when the nucleus material completely tears through the annulus wall, causing a protrusion of nucleus material. This can compress nerve roots and also cause chemical irritation and inflammation. In severe cases, the protruding fragment can completely separate from the disc and travel into the spinal canal where it lodges.