Lumbar Facet Pain: Diagnosis [Clinical Review Discussion]

Several different authors estimate that 15 to 45% of all chronic low back pain is lumbar facet mediated pain (LFMP) (1-4). The “gold standard” for diagnosis, which is recognized by most experts, is a series of two facet blocks using anesthetics which are active for different periods of time. An initial block is given and if the patient receives a significant reduction of pain a second block is performed. If the second provides a longer period of relief then it is assumed the pain arises from the facet (5-8). It must be mentioned when Schulte et al reported on the outcomes of 21 studies of LFMP using injection therapy, radiofrequency therapy or cryorhizotomy only 50% of patients achieved successful outcomes (9). If the pain generator in these cases were the facet joints, why were the results not more impressive? It is possible that the gold standard may be better described as the “best standard available” but not quite golden.

LFMP is a clinically difficult diagnosis to make. The reader should be aware that many experts conclude only 15% of all non disc lesions can be accurately identified on clinical examination (10-14). Even when LFMP is suspected, it may be more accurate to provide a functional diagnosis in many cases.

In an attempt to identify patients for diagnostic blocks, several authors have attempted to determine if there are clinical signs which can accurately predict the presence of LFMP (15-18). The results of these investigations are the basis for the following reviews.