Studies regarding the epidemiology of low back pain are highly variable. The incidence of developing a new episode of back pain has been estimated to be as low as 4 % and as high as 93 % [12–15]. Larger longitudinal studies indicate that this incidence is much lower, i.e., between 3 and 5 %. The incidence of back pain that did not require professional medical care was much higher at 30 % [13]. Prevalence is difficult to study due to variance among study populations and the varying factors that may affect the development of low back pain. Studies estimate that 15–20 % of adults experience memorable low back pain within 1 year. Up to 80 % experience such pain over a lifetime [16–19].

Back pain varies with age as well. Back problems are more often related to claimed disability during the third to fifth decades. These are the prime working years where low back pain leads to the greatest disability and days off work. Interestingly, the symptoms of low back pain do not worsen with age-related degeneration of intervertebral disks [20–24]. Back pain in the elderly is thought to be one of the most important factors to affecting the state of health [25]. Similar to younger adults, the prevalence of back pain in patients older than 65 has been to be 13–49 % [26], but such pain seems to be more episodic and intermittent with a lesser occurrence of chronic pain [27]. Despite the relatively high prevalence of abnormal curvature of the spine in adolescents, the incidence of low back pain is quite low. Some studies suggest that the peak age for development of back pain in children is 13–14 years. Beyond this age, the risk for developing back pain is similar to that of adults [28–30].

Risk factors for the development of low back pain include demographic, physical, socioeconomic, psychological, and occupational factors. It is typically comorbid with other chronic pain and medical conditions. In one study of chronic spinal pain, 68 % reported some type of other chronic pain, 55 % had chronic illness, and 35 % had a mental disorder [31]. Many studies of these risk factors are small and include only self-reports of the variables. A review by Hildebrandt discusses 55 factors related to the individual and 24 occupational factors that have been linked to low back pain [32]. Many studies have looked at the relationship between socioeconomic status and level of education with the development of back pain. The association seems to be not so much with the incidence of pain, but with the ability to adjust to pain. The incidence of disability from back pain was 22–25 times higher in patients with less than 7 years of education compared with those with college degrees [4].

Many people live with low back pain without disability. What is the difference between these patients and disabled patients? In order to understand this, it is important to differentiate between pain and disability. Both are related in that they are generally subjectively relayed by the patient and are not viewed the same in any two patients. There is no objective measure for either of these disorders. Pain is an unpleasant feeling often caused by intense or damaging stimuli. Disability is related to the patient’s perceptions and attitudes about pain [33, 34] and is therefore made up of a host of psychological, social, and cultural issues. It is often based on avoidance, previous painful experiences, and maladaptive coping skills [24, 35, 36].

It is also useful to discuss the difference between acute and chronic pain. Acute pain often bears a close relationship to an inciting event and may be thought to stem directly from tissue injury. Chronic pain, on the other hand, is often due to behavioral adaptations which may have little relationship to the initial physical injury. Therefore it is difficult to treat by medical or surgical means. An example of this is the “failed back syndrome.” Chronic pain becomes a syndrome of emotional distress, depression, and disease conviction [24].

Despite low back pain and sciatica taking center stage in many medical circles today, there is no evidence that the biology of the problem has changed at all over the years. Back pain is the same as it always has been. It is low back disability that is a new concept. Ninety percent of patients with low back pain get better within 6 weeks, in spite of technologically advanced medical and surgical care or interestingly no care at all [3, 21, 24, 37]. This is likely a product of the explosion in the size and complexity of the healthcare systems of western countries and people’s perceptions that the abilities of modern health care should be able to “eliminate” pain. Physicians bear some responsibility in this regard. It is they who “certify” patients with pain to be excused from work, thereby amplifying the global problem of low back disability.

Recent functional imaging studies have borne out what humans have always intrinsically known – pain perception is a multifaceted sensory and emotional experience and thus can be modified by mental, emotional, or sensory mechanisms [38, 39]. It makes most sense, therefore, to attempt to understand primary pain disorders by addressing the entire context of the patient’s illness; this is best approached with the biopsychosocial model. This model stresses the integration of the subjective experience of the patient with the objective physical findings of illness, and that both contribute to the patient’s perception of disease. Engel, the father of this model, emphasizes the responsibility of the physician to treat the body, but also to assist the patient in understanding and adjusting to their illness, along coping with it mentally.

Just as physicians are often frustrated with the inadequacy of treatments available for back pain, many patients are not satisfied with the office visit either. Without the establishment of a diagnosis based on real pathology, the patient often has difficulties putting their pain in context, which can exacerbate anxiety and illness. Disk disease has become so ubiquitous, and patients may be given the nominal diagnosis of disk prolapse, without any signs of nerve root compression or radiographic evidence. It is not long until this nominal diagnosis is confused with real disease pathology, and the patient receives the label of discogenic low back pain. These patients may eventually be treated with surgery that was not indicated and then “bounce” from clinic to clinic when their “curative operation” failed. Clinics are clogged with these patients, thus making it difficult to care for patients with true pathology. Making matters worse, patients will often go from clinic to clinic until a diagnosis is made, resulting in an incentive for physicians to make nominal diagnoses or risk losing patients. Indeed, a large study of the indications for spinal surgery in the mid-1980s showed that surgical decision-making was often driven by the duration and severity of pain and disability, the patient’s illness behavior, and the failure of conservative treatment [40]. As might be expected, the success rate for surgical treatment based on a nominal diagnosis is at best 30–40 %. Interestingly, nearly every study in the last 50 years has shown presence of a psychiatric disease as an extremely poor predictor for good surgical outcome [24, 41–49]. Thus, the responsible surgeon must use the history and physical examination to tease out signs of psychiatric imbalance and consider this carefully prior to proceeding with surgery.

Since complaints of low back pain peak during productive working years, one must discuss this process as it relates to time off work. First, this problem is most prominent in the group of chronic low back pain patients. In a study by Volinn et al., 2 % of workers eligible for industrial insurance filed a claim for back pain in 1 year. Of those, 12 % were off work for 90 days or more, thus consuming more than 88 % of the wage and medical compensation paid by insurance carriers [50]. This same study found that the complaints of back sprain and pain were closely related to workplace dissatisfaction and monotonous job tasks. The medical costs were largely comprised of surgery and hospital stays for “medical back problems.” A study of Medicare patients found that 71 % of these “medical back” hospitalizations were inappropriate [51]. In their review of low back pain and healthcare utilization, Volinn et al. suggest that the level of both cognitive and economic investment in low back pain drives the therapy [52]. Only when further knowledge and education of outcomes regarding the treatment of low back pain become available and third party payers invoke more stringent guidelines for what will and will not be reimbursed will the trends in surgical and medical management change.

The historical and still common practice of “therapeutic rest” appears to be based on multiple fallacies. First, that pain is related to tissue injury and inflammation in the spine, and that rest will help to reverse or alleviate this process. Second, if the pain does not come from inflammation of the spine, it must come from degenerative disk disease, and the only way to allow the disk to heal is with rest. By the disease model of illness, this seems to be a logical progression, but as previously discussed, the disease model of illness does not translate well into the world of low back pain. Considering the biopsychosocial model and assuming that chronic pain is not due to significant injury or to instability of the spine, this treatment does not make sense at all. It aims to treat a process that likely is not active and fails to treat, and may actually worsen, the psychological aspects of the disease. Therefore, it may encourage the assumption of the “sick role.” Indeed, there is only marginal evidence in the literature that suggests that rest improves low back pain or even sciatica. This is a somewhat difficult area to study without a high degree of bias, and as one might expect, the major studies are methodologically flawed. In the majority of these studies, it was found that shorter periods of rest were more beneficial (or less harmful) than longer periods [24]. There have been no studies that suggest that activity worsens pain or tissue injury in the absence of a known pathological correlative lesion. Many of these patients will continue to complain of the same degree of pain, whether they are performing their daily activities or not. It is clear that prolonged rest is harmful to both the body (bone demineralization [53], cardiac deconditioning [54, 55], loss of muscle strength) and mind with depression and anhedonia [56, 57]. The physician who has prescribed rest to the patient with low back pain has clearly done them no favors in the majority of cases.