Lumbar Nerve Root Occupancy in the Foramen in Achondroplasia

Abstract

Lumbar stenosis is common in patients with achondroplasia because of narrowing of the neural canal. However, it is unclear what causes stenosis, narrowing of the central canal or foramina. We performed a morphometric analysis of the lumbar nerve roots and intervertebral foramen in 17 patients (170 nerve roots and foramina) with achondroplasia (eight symptomatic, nine asymptomatic) and compared the data with that from 20 (200 nerve roots and foramina) asymptomatic patients without achondroplasia presenting with low back pain without neurologic symptoms. The measurements were made on left and right parasagittal MRI scans of the lumbar spine. The foramen area and root area were reduced at all levels from L1 to L5 between the patients with achondroplasia

New proposed clinico‐radiologic and molecular criteria in hypochondroplasia: FGFR 3 gene mutations are not the only cause of hypochondroplasia

“…This feature might theoretically equalize their chances of getting lumbar stenosis symptoms. However, it has also been previously reported by Modi et al [2008] that lumbar stenosis symptoms in ACH may not actually be due to the dysplastic bony anatomy of the spine, but FIG. 2.…”

Neutral Endopeptidase-Resistant C-Type Natriuretic Peptide Variant Represents a New Therapeutic Approach for Treatment of Fibroblast Growth Factor Receptor 3–Related Dwarfism

“…In addition, stenosis of the foramen magnum and the spinal canal, caused by premature synchondrosis closure and fusion of ossification centers, is regulated by the same pathway (Hecht and Butler, 1990;Modi et al, 2008;Matsushita et al, 2009). Paracrine/autocrine factor C-type natriuretic peptide (CNP) signals through natriuretic peptide receptor (NPR) B and modulates the activity of FGFR3 through inhibition of the ERK/MAPK pathway at the level of rapidly accelerated fibrosarcoma protein kinase (RAF-1) (Krejci et al, 2005;Horton et al, 2007).…”

Magnetic resonance imaging study determining cord level and occupancy at thoracolumbar junction in achondroplasia — A prospective study

“…In present study, we have included only those patients who had symptoms related to only TL stenosis having TL back pain with girdle pain, difficulty in walking with spasticity with neurological signs of upper motor neuron and not patients of lumbar stenosis causing radicular symptoms. Recently, Modi et al .,15 measured lumbar nerve root occupancy achondroplasia patients (n=17), and showed the similar occupancy in achondroplasia and the nonachondroplasia patients it seems the degenerative changes are the main cause for lumbar stenosis in such population. We have also measured various parameters of spinal canal and spinal cord at the widest level of the conus medullaris and thereby we calculated spinal canal and spinal cord area at that level.…”

“…However, not all achondroplesia patients having interpedicular distance less than 20 mm at L1 or conus level, would develop severe paraperesis. Recently, Modi et al 15. noted that even though the size of foramina narrowed in achondroplasia at lumbar level, the occupancy of lumbar nerve root is not more than normal patients, mainly due to narrowing of lumbar nerve root size.…”