[Problems of diagnostic assessment in low back patients]

Many different diagnostic procedures are used in patients with low back pain. Medical history and clinical examination, X-rays, computed tomography (CT)-scan, magnetic resonance imaging (MRI), diagnostic nerve root blocks and facet injections, functional tests in physiotherapy, strength tests of trunk muscles and work-related performance, and psychological and social evaluation including psychometric tests are only some of them. Despite this large number of procedures available, the scientific literature has not changed its conclusion that in about 80% of all back pain episodes the cause remains unknown. During the course of back pain episodes the relevant factors may change. The cause of the problem or the triggering factor of the pain episode may no longer be important during subacute stages, while others may be decisive for the transition to chronic stages. Thus, assessment of the cause is different from that of prognostic factors. There seems to be no consistent distribution of causes or ongoing factors in the population(s) of patients. While individual social factors may be the one important factor in one patient, functional and structural factors may be significant in another patient. Clinical examination is important, but several problems occur in the evaluation of patients with low back pain. Due to their anatomical location, important bony structures of the lumbar spine, e.g., disks or facet joints, are difficult to access by clinical examination. Additionally, there are only few diagnostic tests during clinical examination that do not rely on the patient's cooperation or communication. The term "unspecific back pain" for the majority of patients is scientifically sound, because it reflects the fact that the cause is unknown. It must be taken into consideration that this term enjoys only limited acceptance by both patients and physicians. Physicians are in charge of certifying work disability by assessing the interference of the patient's illness/disease with the specific requirements of his daily life or job. However, in clinical practice both the job tasks and the patient's abilities to perform these tasks with the given symptoms and signs is still difficult to evaluate and requires further definition.