Novel method for setting up 3D navigation system with skin-fixed dynamic reference frame in anterior cervical surgery

Figures & data

Figure 1. (a) During the draping the patient's forehead and eyes are exposed, and eyebrows are covered with sterile gauze to protect them from adhesive surgical film. (b) Exposed forehead is covered by transparent surgical film. (c) Mount reference frame on the forehead and fix it firmly with fragmented surgical film.

Figure 2. A custom-made metal sleeve (top of picture) can maintain a constant connection between the tip of the caspar pin (bottom right of picture) and the navigation probe (bottom left of picture), none of which were taken handheld. Each tip of caspar pin and navigation probe contacts promptly by the metal sleeve.

Figure 3. (a) A red bidirectional arrow indicates horizontal distance in sagittal plane between center of navigation probe (top) and caspar pin (bottom). (b) A red bidirectional arrow indicates vertical distance in sagittal plane between each end of navigation probe (top) and caspar pin (bottom). (c) Two red lines indicate cobb’s angle in sagittal plane between navigation probe (top) and caspar pin (bottom).

Table 1. Operative procedures.

Operation	No.
ACDF	3
ACF	1
ATF	4
MOC	23
Total	31

ACDF, anterior cervical discectomy and fusion; ACF, anterior cervical corpectomy and fusion; ATF, anterior transcorporeal foraminotomy; MOC, multilevel oblique corpectomy.

Table 2. Measured parameters.

31 cases (N = 48)	Vertical distance	Horizontal distance	Cobb's angle
Mean ± SD	0.88 ± 0.93 mm	0.49 ± 0.71 mm	0.59 ± 0.55°