ADJACENT SEGMENT DISEASE FOLLOWING CERVICAL BRYAN TOTAL DISC ARTHROPLASTY

Abstract

Introduction: ACDF involves cancellation of the diseased spinal motion segment, the neighboring spinal segments take the burden of excessive compensatory spinal movements and strain resulting in early degeneration.

Adjacent segment degeneration with new, symptomatic radiculopathy occurs after ACDF in 2–3% of patients per year on cumulative basis. An estimated 15% of patients ultimately require a secondary procedure at an adjacent level.

An alternative to fusion is total disc arthroplasty (TDA). The key advantage of this promising technology is restoration and maintenance of normal physiological motion rather than elimination of motion.

We describe 4 patients with a serious complication observed following implantation of the Bryan disc prosthesis in our cohort of 48 patients.

Material and Results:

• Patient #1: 43 M, with neck pain & left brachalgia, with left C6 dermatome signs, with MRI findings of C5/6 disc prolapse with left C6 root impingement, undergoing C5/6 Bryan TDA in April 2004, with treatment recommendation of C3/4 and C6/7 Bryan TDA in January 2006.

• Patient #2: 47 M, with worsening gait over 2 years with right brachalgia, with findings of progressive cervical myelopathy with right C5 radiculopathy, with MRI findings of severe C5/6 disc degeneration with spinal cord compression, undergoing C5/6 Bryan TDA in January 2003, with MRI FU findings after 16/12 with new left C6/7 disc prolapse and left C6 radiculopathy, with treatment recommendation of C6/7 Bryan TDA, on waiting list.

• Patient #3: 45 F, 6 years of neck pain with right brachialgia, with right C5 dermatome signs, with MRI findings of C5/6 central disc herniation with cord compression, undergoing C5/6 Bryan TDA in December 2000, with FU MRI showing after 5 years and 7/12 (67/12) new C6/7 canal narrowing with right C6 radiculopathy, and treatment recommendation of C6/7 Bryan TDA.

• Patient #4: 38 M, worsening gait over 5 years and exam findings of progressive cervical myelopathy, with MRI findings of severe C5/6 disc degeneration with spinal cord compression, undergoing C5/6 Bryan TDA in August 2003, with FU MRI showing after 3 years new C4/5 disc prolapse with C5 radiculopathy, followed by treatment recommendation of C4/5 Bryan TDA.

Discussion & Conclusions: Bryan TDR did not prevent the development of accelerated ASD. Evidence from in vivo X ray studies suggested that the range of motion across the operated levels did not match the physiological ROM.

Despite the MRI images preoperatively, it is difficult to exclude the natural progression of degeneration as a reason for ASD.