Clinical and radiographic results of cervical artificial disc arthroplasty: over three years follow-up cohort study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Theoretic advantages of cervical disc arthroplasty include preservation of normal motion and biomechanics in the cervical spine, and reduction of adjacent-segment degeneration. The clinical and radiographic effects of cervical disc arthroplasty in short term have been ascertained. The aim of this study is to research the data of mid-term results.</p><p><b>METHODS</b>In this prospective cohort study, 50 patients who underwent cervical disc arthroplasty from December 2003 to January 2006 were enrolled. There were 39 patients who received 1-level disc arthroplasty, and 11 patients received 2-level disc arthroplasty, with an average age of 50.9 years (range from 29 to 73). The median follow-up was 41.85 months (range from 36.00 - 55.63 months). Patients were followed prospectively with respect to their symptoms, neurologic signs, and radiographic results.</p><p><b>RESULTS</b>The median value of Japanese Orthopaedic Association (JOA) score was 14.0 before surgery, and 16.5 at the most recent follow-up (P < 0.01). The median value of the recovery rate of the JOA score was 92.2%. The preoperative range of motion (ROM) at the indexed level was (10.40 ± 4.97)°, which has significantly correlated with the most recent follow-up ROM which was (8.56 ± 4.76)° (P < 0.05, r = 0.33). The ROM at the operative level at the most recent follow-up was greater than the value at the 3-month follow-up of (7.52 ± 3.37)° (P < 0.05). The preoperative functional spinal unit (FSU) angulation was (-0.96 ± 6.52)°, which was not significantly correlated with that of the most recent follow-up value of (-2.65 ± 7.95)° (P < 0.01, r = 0.53). The preoperative endplate angulation was (2.61 ± 4.85)°, which had no significant correlation with that of the most recent follow-up value of (0.71 ± 6.41)° (P > 0.05).</p><p><b>CONCLUSIONS</b>The clinical and radiographic results of cervical disc arthroplasty are good in mid-term follow-up. The normal range of motion of the operated level and the biomechanics in the cervical spine are well preserved.</p>

Accuracy of CT-based navigation of pedicle screws implantation in the cervical spine compared with X-ray fluoroscopy technique / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility and accuracy of cervical spine pedicle screw fixation assisted by X-ray fluoroscopy and CT-based navigation system.</p><p><b>METHODS</b>145 cervical pedicle screws were placed assisted by X-ray fluoroscopy and 159 cervical pedicle screws were placed assisted by CT-based navigation system. Screw positions were evaluated by postoperative CT scans or C-arm X-ray 3 dimensional reconstruction.</p><p><b>RESULTS</b>In the computer- assisted group, 155 (97.5%) screws were found completely within their pedicles compared with 133 (91.7%) correctly placed screws in the X-ray assisted group (P < 0.05). The process of navigation investigated in twenty patients showed that the mean time for registration and surface matching was 3.5 (range from 2 to 8 minutes) minutes and the mean time for screw-marker insertion was 2 (range from 1 to 3.5 minutes) minutes with the mean position deviation 0.31 mm (0.12-0.56 mm) per screw. Only twice C-arm fluoroscopy were performed to verify the accuracy of one screw position intraoperatively. No severe complications like neurovascular lesion occurred in both groups.</p><p><b>CONCLUSION</b>CT-based navigation system can increase the accuracy of cervical pedicle screw implantation significantly.</p>