C5 palsy after cervical spine decompression surgery.

Degenerative cervical spondylosis and cervical compression myelopathy are common causes of morbidity in middle-aged and elderly individuals. Clinical presentations include progressive spastic quadriparesis, sensory loss at or below the neck, and urinary incontinence. Although nonoperative treatment is acceptable in mild nonprogressive myelopathy, surgical decompression or stabilization is indicated for severe or progressive myelopathy with radiographic evidence of spinal cord compression. The number of patients that require surgery has increased as the population has aged. Decompression of the spinal cord can be achieved through either an anterior or posterior approach. The choice of the surgical approach depends on the etiology of the myelopathy, cervical alignment, and familiarity of the surgeon with a given technique. C5 palsy is a well-known complication of cervical spine decompression surgery. The complication develops regardless of whether a posterior or anterior approach is used. The incidence of C5 palsy ranges from 0% to 30%, depending on how the condition is defined and the patient population. Affected patients suffer from paresis of the deltoid muscle with/without involvement of the biceps brachii muscle and/or brachialgia and numbness. Palsy is typically unilateral but may be bilateral in 5e7% of cases. The initial onset of symptoms ranges from immediately after surgery to 2 months after surgery. Patients with postoperative C5 palsy generally have a good prognosis, with approximately 70% of patients recovering completely within an average of 4e5 months. Pain also generally resolves, but residual pain has been reported in around 20% of cases. Recovery is spontaneous, and no treatment has been shown to improve recovery. However, a worse recovery and a longer recovery period may occur if the patient is severely paralyzed preoperatively. The exact pathogenesis of postoperative C5 palsy remains unknown, and it is likely to be a complex and multifactorial process. Numerous etiologies have been proposed, including direct injury to the nerve root due to the surgical procedure, ischemia and reperfusion injury of the spinal cord, and iatrogenic foraminal stenosis after cervical alignment rearrangement. Increased posterior spinal cord drift due to an increased laminectomy trough width has been reported to be associated with C5 palsy. Furthermore, tethering of the nerve root from the posterior shifting of the spinal cord in association with anchoring of the nerve root at the edge of the uncovertebral joint