A descriptive study of the associations between different neurophysiologic findings in patients with lumbar spinal stenosis.
To evaluate the ability to sense a change in lumbar position and the associations between lumbar movement perception, postural stability, and motor-evoked potentials and somatosensory-evoked potentials.
Patients with low back pain have impaired postural control and impaired lumbar proprioception. Altered motor-evoked potentials and somatosensory-evoked potentials have been often observed in lumbar spinal stenosis.
The study included 26 patients with clinically and radiologically diagnosed lumbar spinal stenosis. Their ability to sense lumbar rotation was assessed in a previously validated motorized trunk rotation unit in the seated position. The abilities to indicate the movement direction and the movement magnitude were used as indexes of the ability to sense the lumbar rotatory movement. The postural stability was measured with a vertical force platform. The motor-evoked potentials were elicited by transcranial and lumbar stimulation and recorded from anterior tibialis muscles. The somatosensory-evoked potentials were elicited by transcutaneous electrical stimulation of the tibial nerve at the ankle.
Twenty patients (76.9%;P = 0.006) reported the wrong movement direction. Furthermore, the patients consistently localized the movement sensation in their shoulders instead of the lumbar region. The altered motor-evoked potentials and somatosensory-evoked potentials were observed in 11 and 16 patients, respectively. Abnormal motor-evoked potentials had inconsistent associations with impaired movement perception and postural stability and abnormal somatosensory-evoked potentials had no associations with other findings.
Many patients with lumbar spinal stenosis have difficulties in sensing the lumbar rotational movement, which may indicate impaired proprioceptive abilities. Abnormal motor-evoked potentials and somatosensory-evoked potentials are also frequent in lumbar spinal stenosis but do not necessarily occur in the same patients as the abnormal ability to sense trunk movement. These new findings add to our understanding of the pathophysiology of lumbar spinal stenosis.
From the Departments of *Physical and Rehabilitation Medicine,
‡Otorhinolaryngology, Kuopio University Hospital, the
§Department of Physiology, University of Kuopio, Kuopio, and
∥DBC International, Vantaa, Finland.
Supported in part by the Finnish Medical Society Duodecim and Kuopio University Hospital EVO Fund.
Acknowledgment date: April 27, 2001.
Revision date: August 24, 2001.
Acceptance date: November 9, 2001.
Device status category: 2.
Conflict of interest category: 14.
Address correspondence to
Ville Leinonen, BM
Department of Physiology
University of Kuopio
P.O. Box 1627
FIN-70211 Kuopio, Finland