J Korean Neurosurg Soc.  2014 Dec;56(6):513-516. 10.3340/jkns.2014.56.6.513.

Usefulness of Intraoperative Monitoring during Microsurgical Decompression of Cervicomedullary Compression Caused by an Anomalous Vertebral Artery

• Kim ST
• Paeng SH
• Jeong DM
• Lee KS

• KMID: 2191148
• DOI: http://doi.org/10.3340/jkns.2014.56.6.513

Abstract

We report a case of cervicomedullary compression by an anomalous vertebral artery treated using microsurgical decompression with intraoperative monitoring. A 68-year-old woman presented with posterior neck pain and gait disturbance. MRI revealed multiple abnormalities, including an anomalous vertebral artery that compressed the spinal cord at the cervicomedullary junction. Suboccipital craniectomy with C1 laminectomy was performed. The spinal cord was found to be compressed by the vertebral arteries, which were retracted dorsolaterally. At that time, the somatosensory evoked potential (SSEP) changed. After release of the vertebral artery, the SSEP signal normalized instantly. The vertebral artery was then lifted gently and anchored to the dura. There was no other procedural complication. The patient's symptoms improved. This case demonstrates that intraoperative monitoring may be useful for preventing procedural complications during spinal cord microsurgical decompression.

Keyword

Vertebral artery; Microvascular decompression; Cervicomedullary junction; Intraoperative monitoring

MeSH Terms

Abnormalities, Multiple
Aged
Decompression*
Evoked Potentials, Somatosensory
Female
Gait
Humans
Laminectomy
Magnetic Resonance Imaging
Microvascular Decompression Surgery
Monitoring, Intraoperative*
Neck Pain
Spinal Cord
Vertebral Artery*

Figure

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  Fig. 1 Sagittal T2-weighted MR images of the cervical spine (A) show the anomalous vertebral arteries (arrows) located dorsal to the spinal cord. Axial T2-weighted MR image of the C1 level (B) shows the anomalous tortuous vertebral arteries (arrows) that compressed the dorsal portion of the spinal cord bilaterally at the cervicomedullary junction. Neither congenital anomalies of the posterior fossa nor any degenerative changes to the spinal column were evident.

• 

  Fig. 2 CT angiography source image (A) and 3D reconstructed image (B) revealed that both vertebral arteries were elongated and enlarged. The hollow indicates the intradural segment of the elongated and enlarged vertebral arteries.

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  Fig. 3 Intraoperative photograph, showing the dura opened into a Y shape, and the elongated and enlarged vertebral arteries (VAs) that seemed somewhat sclerotic. Both the VAs were kissing each other. The C2 rootlets (arrows) were entangled in the VAs.

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  Fig. 4 Amplitude of the somatosensory evoked potential for the right tibialis anterior muscle dropped below 50% of baseline during the operation (red arrow).

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  Fig. 5 Both the vertebral arteries were anchored to the dura (arrow) using Teflon slings and silk sutures. Following that, the area was bonded using surgical glue.

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  Fig. 6 An increase in the motor evoked potentials was noted after dura closure, compared to the baseline values.

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