Can Prophylactic Bilateral C4/C5 Foraminotomy Prevent Postoperative C5 Palsy After Open-Door Laminoplasty? A Prospective Study

Study Design. A prospective study. Objective. To evaluate the effectiveness of prophylactic C4/C5 microforaminotomy with open-door laminoplasty for cervical myelopathy in preventing postoperative C5 palsy. Summary of Background Data. Postoperative C5 palsy is a common complication of cervical laminoplasty. Although the etiology of C5 palsy and preventive measures remain unclear, we hypothesize that C5 palsy is caused by C5 nerve root impairment induced by potential C4/C5 foraminal stenosis and posterior shifting of the spinal cord after laminoplasty. Methods. The study included 141 consecutive patients with cervical myelopathy (103 men and 38 women) who underwent open-door laminoplasty with prophylactic bilateral C4/C5 foraminotomy between 2009 and 2010. These were designated as the foraminotomy group (FG). One hundred forty-one consecutive patients (100 men and 41 women) who underwent open-door laminoplasty without prophylactic foraminotomy during 2006 to 2008 served as a control group. This was the nonforaminotomy group (NFG). The incidence of C5 palsy, operation time, blood loss, and the number of decompressed disc levels were recorded. Results. The incidence of C5 palsy was 1.4% (2 of 141 cases) in the FG, and 6.4% (9 of 141 cases) in the NFG. The mean operation times were 129 and 102 minutes, respectively. There were significant differences in the incidence of C5 palsy and operation time (both comparisons, P < 0.05). There were no significant differences in blood loss or the number of decompressed disc levels (both comparisons, P > 0.05). Conclusion. Prophylactic bilateral C4/C5 microforaminotomy significantly decreased the incidence of postoperative C5 palsy. These results suggest that the main etiology of C5 palsy was C5 root impairment. However, 2 patients experienced C5 palsy despite undergoing prophylactic foraminotomy, which indicated that other factors including spinal cord impairment after acute decompression against cervical canal stenosis may also be considered as minor etiologies of C5 palsy. We conclude that prophylactic C4/C5 foraminotomy was an effective preventive measure against postoperative C5 palsy after laminoplasty.