Answer:
Conjoined Nerve Root left
Findings:Two roots are seen sharing a common sleeve originating from the dura mater(Type 1 -Canon) on the left side at L5-S1 level. There is also apparent asymmetry of the left anterolateral corner of the dural sac with parallel course of nerve root at disc level.
Discussion:Conjoined nerve roots consist of two adjacent nerve roots that share a common dural sleeve as they exit the dural sac. The reported incidence is up to 2% in surgical studies, but it is much higher in symptomatic patients. Three possible signs could be seen: Corner sign (asymmetry of the anterolateral corner of the dural sac); fat crescent sign (extradural fat between the asymmetric dural sac and the conjoined nerve root); parallel sign (parallel course of the entire nerve root at the disc level). Conjoined nerve roots which are asymptomatic and are incidentally discovered need no treatment . These may be associated with ipsilateral bony anomalies like absent pedicle , dysplastic lamina , transverse process and facet .
Ref: Song SJ, Lee JW, et al. Imaging Features Suggestive of a Conjoined Nerve Root on Routine Axial MRI. Skeletal Radiol; 2008; 37 (February): 133-138
Contributed By: Dr. Babu Peter MD. DNB
Associate Professor, Barnard Institute of Radiology, Chennai
Senior Consultant Radiologist, Aarthi Scans, Chennai
Conjoined Nerve Root left
Findings:Two roots are seen sharing a common sleeve originating from the dura mater(Type 1 -Canon) on the left side at L5-S1 level. There is also apparent asymmetry of the left anterolateral corner of the dural sac with parallel course of nerve root at disc level.
Discussion:Conjoined nerve roots consist of two adjacent nerve roots that share a common dural sleeve as they exit the dural sac. The reported incidence is up to 2% in surgical studies, but it is much higher in symptomatic patients. Three possible signs could be seen: Corner sign (asymmetry of the anterolateral corner of the dural sac); fat crescent sign (extradural fat between the asymmetric dural sac and the conjoined nerve root); parallel sign (parallel course of the entire nerve root at the disc level). Conjoined nerve roots which are asymptomatic and are incidentally discovered need no treatment . These may be associated with ipsilateral bony anomalies like absent pedicle , dysplastic lamina , transverse process and facet .
Ref: Song SJ, Lee JW, et al. Imaging Features Suggestive of a Conjoined Nerve Root on Routine Axial MRI. Skeletal Radiol; 2008; 37 (February): 133-138
Contributed By: Dr. Babu Peter MD. DNB
Associate Professor, Barnard Institute of Radiology, Chennai
Senior Consultant Radiologist, Aarthi Scans, Chennai