Abstract
Introduction
Identifying the pathology responsible for the clinically presenting symptoms and signs on the image of lumbar spine is critical for a success of lumbar spine surgery. A nerve root could be compressed within the spinal canal at its preganglion segment, dorsal root ganglion, or both, depending on the pathoanatomy, such as central disc herniation, lateral recess stenosis, or foraminal stenosis. The responsible pathology required to be decompressed has a high impact on the decision of surgical strategy. For a given L5 nerve compression by central disc herniation (L4/5), a simple discectomy is capable to relieve the compression, whereas total facetectomy followed by spinal fusion is required for foraminal stenosis. Sensory deficit in lumbar radiculopathy provides a useful information helping the surgeons identifying the corresponding pathology and planing the surgical strategy. This study is devoted to elucidate the role of the phenotype of sensory deficit in different sites of nerve root compression and to see if the phenotype of sensory deficit is able to predict the compression site on the images.
Materials and Methods
The study prospectively included patients who had degenerative spinal disorders on L4/5 or L5/S1 levels with/without L5 radicular pain. The compressing pathologies on L5 nerve root were divided into three categories: the disc level (L4/5), the pedicle level (L5), and the foremen level (L5/S1). The sensory examination included warm, cold, static mechanical, and dynamic mechanical sensation on the foot dorsum ipsilateral to the pathology, and the foot dorsum contralateral to the pathology on the images served as the control. The association between the sensory examination and the compression sites was analyzed.
Results
A total of 48 patients met the inclusion criteria. The incidences of compressing pathology were 52% (25/48) in the disc level, 43% (21/48) in the pedicle level, and 20% (10/48) in the foramen level. There were 54% (26/48) patients with impaired warm sensation, 45% (22/48) with impaired cold sensation, 27.78% (10/36) with impaired static mechanical stimuli, and 39.58% (19/48) with impaired dynamic mechanical stimuli. The sensory deficit in cold or warm was highly associated with the compressing pathology at the pedicle or foramen level (p = 0.0023) with 78.5% sensitivity and 65% specificity.
Conclusion
Based on our results, different sites of L5 nerve root compression caused different phenotypes of sensory deficit. One should cautiously look for compressing pathology at pedicle/foramen level if the patient presents sensory deficit.
None declared