Adjacent-level biomechanics after single versus multilevel cervical spine fusion.

Object: Previous studies have demonstrated that patients with spinal fusion are at greater risk for adjacent-segment disease and require additional surgery. It has been postulated that excessive motion of a given motion segment unit (MSU) leads to an increased risk of disc degeneration. It is the authors' hypothesis that a greater increase in adjacent-segment motion will be observed following a 2-level versus a single-level anterior cervical discectomy and instrumented fusion (ACDF).

The effect of parallax on intraoperative positioning of the Charité artificial disc.

Study Design: Fluoroscopy imaging evaluation for total disc arthroplasty.

Objectives: To describe the effect of fluoroscopic parallax on the relative position of the Charité and identify the most reliable method for evaluating intraoperative disc position.

Summary Of Background Data: Results of the Investigational Device Exemption study revealed that clinical outcomes of the Charité artificial disc correlated with accurate placement of the prosthesis.