Adverse events of cervical arthroplasty

Rates of adverse events after cervical arthroplasty mirror those of arthrodesis. Different patterns of adverse events occur including those related to any prosthetic devices such as subsidence, heterotrophic ossification, dislodgement, malposition, and infection. The use of proper indications, preoperative planning, and meticulous techniques can avoid the majority of these complications. Sizing and exact placement in the correct mechanical axis is essential and requires accurate biplanar fluoroscopic imaging. Further, spinal related events include clinical failure related to inadequate foramenal decompression and spinal cord injury. Compared with arthrodesis where residual foramenal stenosis may be tolerated, maintenance of motion by arthroplasty may cause loading in the uncus with further hypertrophy and persistent or recurrent symptoms. This is best prevented by assuring wide foramenal decompression at the time of arthroplasty. Spinal cord injury during implantation has not been reported. Wear of the bearing surfaces and formation of debris particles can cause loosening and prosthetic failure. This has not been reported as yet after cervical arthroplasty due to the relatively short time of follow-up for most devices. Two notable cases of apparent metal hypersensitivity causing formation of a pseudotumor have been seen after placement of a metal on metal cobalt-chrome prosthesis. The treatment of malpositioned or hardware-related events is by removal and arthrodesis usually not requiring corpectomy and fusion of other levels. Radiculopathy from foramenal stenosis at the index level site can be resolved with posterior microforamenotomy.