Cervical conjoined nerve root variant: preoperative imaging and surgical confirmation

Case report

Restricted access

✓ A case of a nerve root anomaly in a patient presenting with cervical radiculopathy is presented. The patient was treated with posterolateral exploration and decompression, resulting in relief of pain and improvement in strength. Both the preoperative contrast-enhanced computerized tomography scan and the magnetic resonance image demonstrated an abnormality behind the C-4 body extending from the right C3–4 neural foramen to the neural foramen at C4–5. At surgery, a dural-encased structure was discovered connecting the C-4 and C-5 nerve roots within the spinal canal. This paper describes the first reported case of a cervical nerve root anomaly of this type, representing a variant of a conjoined nerve root. The occurrence of such nerve root anomalies in the cervical spine should be entered into the differential diagnosis and treatment of cervical radiculopathy.

Article Information

Address reprint requests to: Randall M. Chesnut, M.D., Division of Neurosurgery, University of California-San Diego Medical Center, 200 West Arbor Drive, San Diego, California 92103–8893.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    Plain x-ray film, lateral view, of the cervical spine after injection of iohexol revealing effacement of the anterior column of contrast material at the C3–4 interspace.

  • View in gallery

    Contrast-enhanced computerized tomography scans from the C3–4 to the C4–5 level. The mass (arrows) appears to exert a minimal mass effect on the cord. Left: Scan showing a low-attenuation mass surrounded by contrast enhancement in the right ventrolateral aspect of the C3–4 canal without observable mass effect. Center: Scan demonstrating continuation of the mass at the level of the C-4 vertebral body with dissipation of contrast enhancement along the lateral aspect. Right: Scan of the C4–5 interspace showing that the surrounding contrast enhancement has disappeared.

  • View in gallery

    Left and Center: Fat-suppression axial magnetic resonance (MR) imaging studies at C-4 (left) and C4–5 (center) demonstrating a right ventrolateral area of low signal (arrow) surrounded by cerebrospinal fluid density. Right: T1-weighted right parasagittal MR image demonstrating a structure (arrows) appearing to arise from the cord at the C3–4 level and extending inferiorly to the level of the C4–5 disc.

  • View in gallery

    Intraoperative photograph showing a dura-encased structure (arrow) arising in the axilla of the C-4 nerve root (4) and traveling separately along the dura to the C-5 nerve root (5), where it re-enters the dura. The lateral edge of the dura is indicated by the arrowhead, and an epidural vein is being retracted with a No. 4 Penfield retractor. P = C-4 pedicle.

References

1.

Bell GRRoss JS: Diagnosis of nerve root compression. Myelography, computed tomography, and MRI. Orthop Clin North Am 23:4054191992Bell GR Ross JS: Diagnosis of nerve root compression. Myelography computed tomography and MRI. Orthop Clin North Am 23:405–419 1992

2.

Epstein JACarras RFerrar Jet al: Conjoined lumbosacral nerve roots. Management of herniated discs and lateral recess stenosis in patients with this anomaly. J Neurosurg 55:5855891981Epstein JA Carras R Ferrar J et al: Conjoined lumbosacral nerve roots. Management of herniated discs and lateral recess stenosis in patients with this anomaly. J Neurosurg 55:585–589 1981

3.

Okuwaki TKunogi JHasue M: Conjoined nerve roots associated with lumbosacral spine anomalies. A case report. Spine 16:134713491991Okuwaki T Kunogi J Hasue M: Conjoined nerve roots associated with lumbosacral spine anomalies. A case report. Spine 16:1347–1349 1991

4.

Peyster RGTeplick JGHaskin ME: Computed tomography of lumbosacral conjoined nerve root anomalies. Potential cause of false-positive reading for herniated nucleus pulposus. Spine 10:3313371985Peyster RG Teplick JG Haskin ME: Computed tomography of lumbosacral conjoined nerve root anomalies. Potential cause of false-positive reading for herniated nucleus pulposus. Spine 10:331–337 1985

5.

Rosner MJWhaley R: Anomalous exit of the C-6 nerve root via the C-6, C-7 foramen. Neurosurgery 14:7407431984Rosner MJ Whaley R: Anomalous exit of the C-6 nerve root via the C-6 C-7 foramen. Neurosurgery 14:740–743 1984

TrendMD

Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 661 661 192
Full Text Views 440 440 7
PDF Downloads 139 139 8
EPUB Downloads 0 0 0

PubMed

Google Scholar