Prospective Study and Multivariate Analysis of the Incidence of C5 Palsy After Cervical Laminoplasty

Study Design: A prospective comparative study about the incidence of postoperative C5 palsy and multivariate analysis of the risk factors of C5 palsy.

Objective: To clarify the risk factors of occurrence of C5 palsy after laminoplasty (LP) by comparing the 2 surgical procedures of open-door and double-door LP prospectively.

Summary Of Background Data: The incidence of C5 palsy has been reported to average 4.6%, and there has been no difference of the incidence among surgical procedures. However, there were only indirect retrospective studies.

Methods: A total of 146 patients who underwent the LP procedure between 2006 and 2007 were studied prospectively. In 2006, the patients were assigned to undergo the open-door LP, and in 2007, they were assigned to undergo the double-door LP. The incidence of postoperative C5 palsy was compared prospectively between these 2 LP procedures, and the risk factors of C5 palsy were detected with multivariate logistic regression analysis.

Results: Postoperative C5 palsy occurred in 7 of 73 cases after open-door LP (9.6%) and in 1 of 73 cases after double-door LP (1.4%). The incidence of C5 palsy after open-door LP was statistically higher than the one after double-door LP (P = 0.029), and open-door LP was recognized as a significant risk factor for postoperative C5 paralysis (odds ratio: 69.6, P = 0.043). In addition, ossification of posterior longitudinal ligament (OPLL) was recognized as a significant risk factor for postoperative C5 paralysis (odds ratio: 43.8, P = 0.048).

Conclusion: This study showed significant evidence indicating the higher risk of postoperative C5 palsy in open-door LP than double-door LP. Because OPLL as well as open-door LP were recognized as the risk factors of C5 palsy, asymmetric decompression by open-door LP might introduce imbalanced rotational movement of spinal cord and result in C5 palsy. We recommend double-door LP to minimize the postoperative C5 palsy, in particularly, if the patient has OPLL.