Image-guided screw placement offers “advantage” in instrumented spinal surgery


A retrospective review of patients undergoing instrumented spinal surgery has concluded that the use of image-guided navigation may offer an advantage compared to fluoroscopy-assisted and freehand screw placement. This was the finding of James Towner (University of Rochester Medical Center; Rochester, USA) in a study published ahead of print by the Clinical Spine Surgery journal. However, despite concluding that image-guided surgery does offer an advantage over alternatives, the findings failed to reach statistical significance.

According to Towner and colleagues, the use of image-guided navigation has become increasingly commonplace in instrumented spine surgery, but they claim that there is a lack of information regarding differences in the rates of clinically-relevant screw malposition with image-guided compared to non-navigated screw placement.

Therefore, the objective of the study is to determine if the use of image-guided navigation offers a clinically significant advantage over fluoroscopy-assisted pedicle screw and non-navigated screw placement in reducing the risk of revision surgery for malpositioned screws in instrumented spinal surgery. The study team analysed a cohort series of consecutive patients who underwent instrumented spinal surgery by the senior authors at two academic tertiary care centres in New York, USA.

A total of 663 instrumented spinal surgeries were analysed, including 271 instances with image-guided navigation. For the image-guided navigation cohort, 110 of the patients underwent screw placement using O-Arm image-guidance, yielding data on 1,115 screws. The remaining 161 surgeries utilising image-guided screw placement were performed using Brainlab Spine Navigation, for a total of 1,001 screws.

A fluoroscopy-assisted technique or freehand technique was used in 419 instances, with a total of 3,689 screws. Of the non-navigated cohort, 10 patients required a surgical revision of screw placement, for a total of 15 malpositioned screws. Amongst the image-guided navigation cohort, one patient in the O-Arm group and two in the Brainlab group required revision surgery, with three malpositioned screws in total. The rate of revision surgery for a malpositioned screw placed via non-navigated techniques was 2.39%. This risk was decreased to 1.11% with the use of the intraoperative image-guided navigation, the study team found. However, no comparisons between non-navigated and image-guided screw placement reached statistical significance.

In conclusion, Towner and colleagues write that, although not reaching statistical significance, these data suggest there may be an advantage offered by image-guided screw placement in instrumented spinal surgery.


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