title: Clinical usefulness of assessing lumbar somatosensory evoked potentials in lumbar spinal stenosis. Clinical article.
abstract: OBJECTIVE
  The aim of this retrospective study was to evaluate the clinical usefulness of assessing lumbar somatosensory evoked potentials (SSEPs) in central lumbar spinal stenosis (LSS).
  
  
  METHODS
  The latencies of lumbar SSEPs were recorded in 40 patients with central LSS, including 16 men and 24 women. The mean age of the patients was 67.3 +/- 7.4 years. The diagnosis was LSS in 23 cases and LSS associated with degenerative spondylolisthesis in 17 cases. The average duration of symptoms was 43.8 +/- 51.2 months. Twenty-two cases had bilateral and 18 cases had unilateral leg symptoms. Thirty-seven cases were associated with neurogenic intermittent claudication and the mean walking distance of patients with this condition was 246.8 +/- 232.7 m. The mean Japanese Orthopedic Association scale score, as well as the visual analog scale (VAS) scores of low-back pain, leg pain, and numbness, were 16.5 +/- 3.5, 6.0 +/- 2.5, 6.9 +/- 2.1, and 7.8 +/- 2.2, respectively. The minimal cross-sectional area of the dural sac on MR imaging was 0.44 +/- 0.21 cm(2). Thirty-nine cases of cervical spondylotic myelopathy without lumbar and peripheral neuropathy were chosen as the control group.
  
  
  RESULTS
  The latencies of lumbar SSEPs in patients with LSS and in the control group were 23.0 +/- 2.0 ms and 21.6 +/- 1.9 ms, respectively. There was a statistically significant difference between the LSS and control groups (p < 0.05). The latency of lumbar SSEPs was significant correlated with the VAS score of leg numbness (p < 0.05). The latency of lumbar SSEPs in LSS was clearly delayed when the VAS score of leg numbness was > or = 8 (p < 0.05).
  
  
  CONCLUSIONS
  Lumbar SSEPs are able to detect neurological deficit in the lumbar area effectively, and they can reflect part of the subjective severity of sensory disturbance (numbness) in LSS. Both lumbar SSEPs and VAS scores of leg numbness may be useful for clinical evaluation in patients with LSS.
authors: Department of Orthopedic Surgery, Nippon Medical School, Tokyo, Japan. newyuliu@hotmail.com
authors: Xinyu
authors: X
authors: Liu
authors: Shunsuke
authors: S
authors: Konno
authors: Masabumi
authors: M
authors: Miyamoto
authors: Yoshikazu
authors: Y
authors: Gembun
authors: Gen
authors: G
authors: Horiguchi
authors: Hiromoto
authors: H
authors: Ito
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D006987:Hypesthesia / Q000209:etiology / Q000503:physiopathology; D007866:Leg / Q000503:physiopathology; D017116:Low Back Pain / Q000209:etiology / Q000503:physiopathology; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D012189:Retrospective Studies; D013130:Spinal Stenosis / Q000150:complications / Q000503:physiopathology*