A 35-year-old woman who suffered from a motor vehicle accident, was initially sent to the orthopedics department at the Second Affiliated Hospital of Wenzhou Medical College. The patient complained of severe neck pain with slight numbness in the ring and little fingers, and limited motion of the neck. Physical examination showed apparent tenderness of the seventh cervical spinous process. The neck pain became more severe in the positions of flexion, extension and lateral bending. Neurological examination demonstrated that sensory perception of the ring and little fingers was diminished, and normal motor function was limited. Lateral X-ray film and computed tomography (CT) scans of the cervical spine revealed that pedicles of the seventh cervical vertebra were fractured, and the seventh cervical vertebra had slipped forward. The integrity of facet joints was intact (Fig. 1A, B). No spinal cord compression, edema or hemorrhage was seen on magnetic resonance images (Fig. 1C). Primary management at our institution included axial traction via Gardner-Wells calipers for 2 days. Lateral radiograph confirmed a near-anatomic reduction of the fracture. The surgical procedure was subsequently conducted.

After generalanesthesia, the patient was positioned prone on the operating table. Two small rolls were put under the shoulders to keep the neck slightly flexed. The head was placed in a U-type tractor and the shoulders were pulled caudally by heavy bandages to obtain a clear intraoperative lateral radiographic image of the seventh cervical spine. Spinal somatosensory evoked potential was monitored throughout the operation to monitor the physiological changes of spinal cord and nerves. Preoperatively, the bilateral skin entry point was measured in the axial plane of the CT scan, (about 3 cm relevant to the midline) (Fig. 1B). The position of skin entry point was the intersection point of the extension line of the seventh cervical pedicle axis with the posterior skin of the neck. The lateral angulation of the pedicle screw relative to the midline was also measured bilaterally on the same scan (approximately 30°) (Fig. 1B). According to the measured parameters, a 5 mm initial incision was made, about 3 cm from the midline at the level of the seventh cervical pedicle. A 1.2 mm K-wire with a sharp tip was inserted and adjusted to reach the entry point (the midpoint of the lateral border of the pedicleon anteroposterior [AP] view) with fluoroscopic assistance. The procedure was repeated on the other side. We adjusted the position of the K-wires until they reached an angle of approximately 30° lateral to the sagittal plane on an AP image, and paralleled the upper end-plate of the seventh cervical vertebra on a lateral view (Fig. 2A, B). The K-wires were then implanted into the seventh cervical pedicle across the fracture line with a power-drill, reaching the anterior cortex of the vertebral under fluoroscopic guidance (Fig. 2C). The depth of penetration was determined by the depth gauge, when the position of the K-wire was satisfactory. The guide tube (5.8 mm outer diameter, 1.2 mm inner diameter) was inserted over the K-wire. A protection sleeve, with a 7 mm outer diameter and 6.1 mm inner diameter, was advanced along the guide tube. The guide tube was subsequently withdrawn. A recess for the screw head was made using the cannulated drill bit sliding over the K-wire. Care must be taken to avoid advancing the K-wire further while drilling. A 3.5 mm partially-threaded self-tapping cannulated screw was then placed over the K-wire inside the protection sleeve (Fig. 2D). Once the screw was well positioned, the K-wire and sleeve were removed simultaneously. The same approach was taken at the opposite side (Fig. 2E). Closure of the wound was performed with one stitch after checking for hemostasis.

There were no operation-related complications during the postoperative period. The patient was discharged from the hospital 4 days postoperatively, and a soft collar was placed for 8 weeks. She was followed-up at 18 months, with lateral cervical X-rays and CT that showed solid union of fractures of the seventh cervical vertebra. No pain and neurologic deficit was observed. The neck motions were normal (Fig. 3).