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Greater pedicle screw accuracy seen with navigation used in spinal deformity cases
Two screws pierced the anterior or lateral cortex in the navigated group vs. 38 in the control group.
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Many studies showing that computer-assisted navigation aids in pedicle screw placement have involved cadavers or simple spine surgeries. Now, clinical research indicates that using a navigation system that provides intraoperative, 3-D imaging may be advantageous for thoracic deformity procedures.
S. Rajasekaran, PhD, FRCS, MS(Orth), and colleagues compared the results of 33 spinal deformity patients who were randomized to receive surgery either under fluoroscopic control or using an intraoperative navigation system (Siremobil ISO-C, BrainLAB, Germany) to assess the accuracy of navigated screw placement.
C-arm shift
Evaluation by CT scan revealed that the navigated group had significantly fewer pedicle breeches of the canal, significantly fewer screws penetrating the anterior or lateral cortex and a faster average screw insertion time.
They also discovered that the C-arm shifted into the operative field 1.5±0.25 times per screw in the non-navigated group, while the mobile C-arm of the navigation system minimized the surgeon’s radiation exposure.
“We found that [navigation] significantly improves accuracy in pedicle placement, reduces radiation exposure, particularly to the surgeon, and it reduces time taken per screw,” Rajasekaran said during his presentation at the American Academy of Orthopaedic Surgeons 75th Annual Meeting.
Pedicle breeches
The study included 27 patients with scoliosis and six patients with kyphosis who underwent surgery using a total of 478 titanium pedicle screws.
Using CT scans, the investigators evaluated screw placement using four-point grading scale with Grade zero denoting accurate screw placement and Grade III denoting critical encroachment of the canal. They found that the navigated group had only five (2%) pedicle breeches categorized as greater than a Grade II compared to 54 (23%) in the non-navigated group. In addition, two screws in the navigated group pierced the anterior or lateral cortex compared to 38 screws in the non-navigated group.
For more information:
- S. Rajasekaran, PhD, FRCS, MS (Orth), can be reached at Ganga Hospital, Swarnambika Layout, Ramnagar, Coimbatore: 641009, Tamilnadu, India; 91-0-422-2235050; sr@gangahospital.com. He has no direct financial interest in any products or companies mentioned in this article.
Reference:
- Randomized clinical study to study accuracy of navigated pedicle screws in deformity surgeries. Paper #173. Presented at the American Academy of Orthopaedic Surgeons 75th Annual Meeting. March 5-9, 2008. San Francisco.