Lumbar Canal Stenosis

Overview

  • Narrowing of the central canal, lateral recess or foramina
  • Disc bulge, facet hypertrophy and ligamentum flavum thickening, sometimes with degenerative spondylolisthesis
  • Neurogenic claudication, buttock and leg pain on walking relieved by sitting or flexion
  • Distinguish from vascular claudication
  • MRI is the investigation of choice
  • Many improve or stay stable with physiotherapy and analgesia
  • Decompression, with or without fusion, gives good results for leg symptoms

Western Health Orthopaedic Registrar presentation –  Lumbar Canal Stenosis By Dr Glenn Gomez

Anatomy

  • Lateral recess stenosis compresses the traversing root (L5 at L4/5)
  • Foraminal stenosis compresses the exiting root (L4 at L4/5)

Aetiology

  • Degenerative is most common, with disc bulge, facet hypertrophy and ligamentum flavum buckling
  • Degenerative spondylolisthesis, most often at L4/5

Classification

Schizas (axial T2 MRI)

GradeDescription
ACSF clearly visible
BRootlets fill the sac but can be individualised
CNo CSF, rootlets indistinguishable, posterior fat present
DNo CSF and no posterior epidural fat

Original publication Schizas C, Theumann N, Burn A, Tansey R, Wardlaw D, Smith FW, Kulik G. Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on magnetic resonance images. Spine (Phila Pa 1976). 2010;35(21):1919-24.

  • C and D are severe and more often fail non-operative care

Clinical Features

  • Relief with sitting or flexion (shopping trolley sign), uphill better than downhill, cycling tolerated
  • Vascular claudication gives calf pain relieved by standing still, absent pulses and pain on cycling

Investigations

Lumbar Canal Stenosis, sagittal mri of lumbar spinal stenosis
Sagittal MRI of lumbar spinal stenosis. Image by Jmarchn, Wikimedia Commons, CC BY-SA 3.0.
  • Flexion and extension films for dynamic instability
  • MRI is the investigation of choice, CT myelography if contraindicated

Management

  • LESS trial found little benefit of epidural steroid over local anaesthetic
  • Decompression preserves the pars and half of each facet
  • SPORT favoured surgery in the as-treated analysis
  • Swedish Spinal Stenosis Study found no benefit from adding fusion
  • SLIP found a modest fusion advantage in stable grade 1 spondylolisthesis
  • NORDSTEN-DS found decompression alone non-inferior
  • Fusion for dynamic instability, deformity or wide facetectomy

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.