JOURNAL ARTICLE

Effect of two-level total disc replacement on cervical spine kinematics

Frank M Phillips, Michael N Tzermiadianos, Leonard I Voronov, Robert M Havey, Gerard Carandang, Andrew Dooris, Avinash G Patwardhan
Spine 2009 October 15, 34 (22): E794-9
19829242

STUDY DESIGN: Biomechanical study using human cadaver spines.

OBJECTIVE: To characterize kinematics of cervical spines implanted with total disc replacement (TDR) at 2-levels referencing the implanted and adjacent levels.

SUMMARY OF BACKGROUND DATA: Cervical TDR is an appealing alternative to fusion particularly when treating multilevel disease, where the advantages of maintaining motion and reducing adjacent level stresses with TDR are compelling. To our knowledge there are no biomechanical studies evaluating multilevel cervical TDR.

METHODS: Six human cadaveric cervical spine specimens (C3-C7, age: 57 +/- 12 years) were tested (i) intact, (ii) after TDR (Discover, DePuy, Raynham, MA) at C5-C6, and (iii) after additional TDR at C6-C7. Specimens were subjected to flexion/extension, lateral bending and axial rotation (+/-1.5 Nm). Segmental range of motion (ROM) was measured using optoelectronic instrumentation and fluoroscopy.

RESULTS: Insertion of TDR at C5-C6 increased flexion/extension ROM of the implanted segment compared with intact (8.6 +/- 1.0 vs. 12.3 +/- 3.3 degrees , P < 0.025). The TDR maintained ROM to intact levels in lateral bending (7.4 +/- 2.6 vs 6.0 +/- 1.6, P > 0.025) and axial rotation (5.5 +/- 1.9 vs. 6.0 +/- 2.9, P > 0.025). The TDR at C5-C6 did not affect ROM at the adjacent levels. Implantation of a second TDR at C6-C7 maintained the ROM at that segment to intact values in flexion/extension (9.6 +/- 4.3 vs. 11.2 +/- 5.5, P > 0.025), lateral bending (6.1 +/- 4.0 vs. 4.1 +/- 2.1, P > 0.025), and axial rotation (6.7 +/- 3.6 vs. 5.5 +/- 3.7, P > 0.025). The second TDR at C6-C7 did not affect the ROM of the prosthesis implanted at C5-C6. Two-level TDR at C5-C6-C7 did not affect the ROM at C4-C5 in flexion/extension or axial rotation, however, in lateral bending a small increase occurred (8.9 +/- 3.6 vs. 10.1 +/- 4.5, P < 0.025).

CONCLUSION: Cervical TDR at 2 levels can provide near-normal mobility at both levels without destabilizing the implanted segments or affecting adjacent segment motions. These observations lend support to the notion that single or multilevel cervical TDR may be advantageous when compared to fusion.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
19829242
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"