title: Hidden spondylolisthesis: unrecognized cause of low back pain? Prospective study about the use of dynamic projections in standing and recumbent position for the individuation of lumbar instability.
abstract: BACKGROUND
  Dynamic X-rays (DXR) are widely recognized as an effective method to detect lumbar instability (LI). They are usually performed with the patient in standing position (SDXR). In our opinion, standing position inhibits micromovements of the lumbar segment interested by the listhesis, thanks to paravertebral muscles antalgic contraction and augmented tone. We aim to demonstrate that DXR in recumbent position (RDXR), reducing the action of paravertebral muscles, can discover hypermovements not evidenced in SDXR.
  
  
  METHODS
  Between January 2011 and January 2013, we studied 200 consecutive patients with lumbar degenerative disease with MRI, SDXR, and RDXR. We aimed to find a correlation between low back or radicular pain and the presence of a spondylolisthesis not showed by the SDXR, but showed by the RDXR.
  
  
  RESULTS
  We analysed 200 patients: of the 133 not pathologic in SDXR, 43 patients (32.3 %) showed an hypermovement in RDXR (p = 0.0001) without any significant correlation between hidden listhesis and age, sex, or level involved.
  
  
  CONCLUSIONS
  The aim of our study is to determine whether in patients with lumbalgy without evidence of listhesis in SDXR, pain can be attributed to a faccettal syndrome or to a spondylolisthesis. Consequence of pain is augmented muscular tone of the paravertebral musculature, particularly in standing position. Augmented muscular tone tries to inhibit the pain generator, attempting to limit the slippage of the involved segment. In patients examined in RDXR, the tone of paravertebral musculature is reduced, showing the hidden spondylolisthesis.
authors: Department of Neurology and Psychiatry, Division of Neurosurgery, "Sapienza" University of Rome - Policlinico Umberto I, viale del Policlinico 155, 00181, Rome, Italy, dott.alessandro.landi@gmail.com.
authors: Alessandro
authors: A
authors: Landi
authors: Fabrizio
authors: F
authors: Gregori
authors: Nicola
authors: N
authors: Marotta
authors: Pasquale
authors: P
authors: Donnarumma
authors: Roberto
authors: R
authors: Delfini
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000000981:diagnostic imaging* / Q000209:etiology; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D064170:Paraspinal Muscles; D011187:Posture; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D013168:Spondylolisthesis / Q000150:complications / Q000000981:diagnostic imaging*