Computer-assisted navigation for dorsal percutaneous scaphoid screw placement: a cadaveric study

Area of Science:

• Orthopedic Surgery
• Medical Imaging
• Computer-Assisted Surgery

Background:

• Percutaneous scaphoid screw fixation is a common orthopedic procedure.
• Traditional methods often rely on fluoroscopy and mini C-arm imaging.
• Minimally invasive techniques aim to improve patient outcomes and reduce radiation exposure.

Purpose of the Study:

• To evaluate the efficacy of computer-assisted surgery (CAS) for dorsal percutaneous scaphoid screw insertion.
• To compare CAS with the traditional mini C-arm method regarding operative time, accuracy, and fluoroscopy time.
• To test the hypothesis that CAS improves accuracy and reduces K-wire insertion and fluoroscopy times.

Main Methods:

• Ten cadaveric upper limbs underwent randomized dorsal percutaneous scaphoid screw placement using either CAS or a traditional mini C-arm.
• CAS involved custom orthoses, intraoperative computed tomography (CT) scans, and navigation calibration.
• Outcome variables included setup time, guidewire placement time, fluoroscopy time, and accuracy confirmed by postoperative CT scans.

Main Results:

• The CAS group had a longer setup time (4.8 ± 0.8 minutes) but significantly reduced guidewire placement time (4.6 ± 1.5 minutes vs. 11.8 ± 4.4 minutes).
• Fluoroscopy time was substantially lower in the CAS group (18 ± 4 seconds vs. 114 ± 38 seconds).
• Accuracy was comparable between groups, with a maximum deviation of 1.5 ± 0.6 mm in the CAS group; no significant differences in accuracy or total surgical time were observed.

Conclusions:

• CAS navigation for dorsal percutaneous scaphoid screw placement is as accurate as the traditional method.
• CAS significantly reduces guidewire placement and fluoroscopy time, offering a 6-fold reduction in radiation exposure.
• This CAS approach is an effective alternative to mini C-arms for scaphoid fixation, utilizing existing intraoperative CT scanners and navigation software.