Accuracy of the Gutter Position in Cervical Double-door Laminoplasty Using Intraoperative Computed Tomography Navigation and the Factors Associated With C5 Palsy.

STUDY DESIGN

This was a prospective study.

OBJECTIVE

This study aimed to investigate the accuracy of the gutter position after cervical double-door laminoplasty (LP) using intraoperative computed tomography (CT) navigation and the factors associated with C5 palsy.

SUMMARY OF BACKGROUND DATA

There were some reports in which the gutter position and the width of decompression in cervical LP were associated with C5 palsy; however, there were few reports about the accuracy of the gutter position.

MATERIALS AND METHODS

Thirty-three patients treated with cervical LP were enrolled. We marked our targeted gutter position on the lamina with a high-speed drill using intraoperative CT navigation and performed the LP procedure. The accuracy of the gutter position was evaluated with a postoperative CT scan. We measured the angle of the opened lamina (AOL), the proportion of the distance between the gutters and the distance of transverse diameter of spinal canal (PGSC) with a postoperative CT scan and spinal cord posterior shifting (SCPS) with preoperative and postoperative magnetic resonance imaging scans. We investigated the incidence of C5 palsy and analyzed AOL, PGSC, and SCPS between the C5 palsy (+) and (-) groups.

RESULTS

The accuracy of all gutter positions was 78.4% (182/232). The accuracy of the gutter position at the right C4 and right C7 was lower than that at the other levels. The AOL in all cases was ~60 degrees. The PGSC was 90.1%-97.2%. The SCPS at C5 was the largest with 2.2 mm. C5 palsy occurred in 3 of 33 patients (9.1%). There were no significant differences in the AOL, PGSC, or SCPS between the 2 groups.

CONCLUSIONS

The accuracy of the gutter position using intraoperative CT navigation was good. The incidence of C5 palsy was higher in this study than in the previous reports.