Acute central canal dilatation after minimally invasive lateral cervical decompression through the Frykholm approach.

STUDY DESIGN: A case report to describe the first case of an acute central canal dilatation after minimally invasive lateral cervical decompression.

OBJECTIVE: To emphasize the need of being aware of this rare spinal disorder.

SUMMARY OF BACKGROUND INFORMATION: A holocord syrinx is known as a complication of Chiari malformation. Furthermore, it can occur spontaneously, after trauma or infection.

METHODS: A 63-year-old patient with a left-sided nerve root stenosis, C3/C4, because of uncovertebral and intervertebral joint osteoarthritis with paresis of the left deltoid muscle, underwent minimally invasive decompression of the C4 nerve root according to the Frykholm approach.

RESULTS: An immediately postoperative recognizably complete paresis of the right arm was because of hydromyelia from the fourth ventricle down to the thoracic spine. A minimal edema of the spinal cord was present. No abnormality of the spinal cord had been detected on preoperative magnetic resonance imaginary (MRI).At revision surgery high pressure was found within the hydromyelia. Subarachnoid drainage did not improve the neurologic deficits. On account of increasing edema of the spinal cord paraplegia developed, which almost completely resolved after further revision.

CONCLUSION: The reason for the hydromyelia is unclear. Routinely used MRI is not able to detect a collapsed central canal of the spinal cord. Acute hydromyelia causes permanent neurologic deficits whereas edema might lead to transient disturbances.