title: Visually assessed severity of lumbar spinal canal stenosis is paradoxically associated with leg pain and objective walking ability.
abstract: BACKGROUND
  Lumbar spinal stenosis (LSS) is the common term used to describe patients with symptoms related to the anatomical reduction of the lumbar spinal canal size. However, some subjects may have a markedly narrowed canal without any symptoms. This raises the question of what is the actual role of central canal stenosis in symptomatic patients. The purpose of this study was to compare radiological evaluations of LSS, both visually and quantitatively, with the clinical findings of patients with LSS.
  
  
  METHODS
  Eighty patients [mean age 63 (11) years, 44% male], with symptoms severe enough to indicate LSS surgery, were included in this prospective single-center study. Lumbar magnetic resonance imaging was performed and one experienced neuroradiologist classified patients into three groups: 0 = normal or mild stenosis, 1 = moderate stenosis, and 2 = severe stenosis. In addition, the same observer measured the minimal dural sac area level by level from the inferior aspect of L1 to the inferior aspect of S1. The association between radiological and clinical findings were tested with Oswestry Disability Index, overall visual analog pain scale, specific low back pain, specific leg pain, Beck Depression Inventory, and walking distance on treadmill exercise test.
  
  
  RESULTS
  In the visual classification of the central spinal canal, leg pain was significantly higher and walking distance achieved was shorter among patients with moderate central stenosis than in patients with severe central stenosis (7.33 (2.29) vs 5.80 (2.72); P = 0.008 and 421 (431) m vs 646 (436) m; P = 0.021, respectively). Patients with severe stenosis at only one level also achieved shorter walking distance than patients with severe stenosis of at least two levels. No correlation between visually or quantitatively assessed stenosis and other clinical findings was found.
  
  
  CONCLUSIONS
  There is no straightforward association between the stenosis of dural sac and patient symptoms or functional capacity. These findings indicated that dural sac stenosis is not the single key element in the pathophysiology of LSS.
authors.affiliation: Department of Neurosurgery, Kuopio University Hospital, Puijonlaaksontie 2, PO Box 1777, Kuopio 70210, Finland. pekkaku@student.uef.fi.
authors.forename: Pekka
authors.initials: P
authors.lastname: Kuittinen
authors.forename: Petri
authors.initials: P
authors.lastname: Sipola
authors.forename: Tapani
authors.initials: T
authors.lastname: Saari
authors.forename: Timo Juhani
authors.initials: TJ
authors.lastname: Aalto
authors.forename: Sanna
authors.initials: S
authors.lastname: Sinikallio
authors.forename: Sakari
authors.initials: S
authors.lastname: Savolainen
authors.forename: Heikki
authors.initials: H
authors.lastname: Kröger
authors.forename: Veli
authors.initials: V
authors.lastname: Turunen
authors.forename: Ville
authors.initials: V
authors.lastname: Leinonen
authors.forename: Olavi
authors.initials: O
authors.lastname: Airaksinen
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007866:Leg / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis* / Q000209:etiology; D010147:Pain Measurement / Q000379:methods*; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D012720:Severity of Illness Index; D013130:Spinal Stenosis / Q000150:complications / Q000175:diagnosis*; D016138:Walking