STUDY DESIGN: A prospective study. OBJECTIVE: To examine the prevalence and clinical manifestations of segmental motor paralysis after cervical laminoplasty and to investigate the presence of intramedullary high-signal intensity area (HIA) on postoperative T2-weighted magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: Almost all previous studies had been retrospectively conducted, and MRIs of all subjects, including a control population, have never been investigated. METHODS: In the 79 patients of the prospective group, the sole examiner evaluated muscle strengths daily for perioperative 3 weeks and MRI scans were performed before and after surgery. Medical records of the 79 consecutive patients before this study were also investigated (control group). RESULTS: Ten patients from the prospective group developed segmental motor paralysis (proximal in 5, distal in 2, and diffuse in 3), whereas paralysis occurred in only 4 patients from the control group (proximal in 3 and diffuse in 1). On postoperative MRI, a linear HIA corresponded to the paralyzed segment more frequently than a focal or no HIA. CONCLUSION: In the prospective cases, distal or diffuse paralysis was found more frequently than in the retrospective control group. Linear HIAs were significantly more likely to present in the paralyzed segments.
STUDY DESIGN: A prospective study. OBJECTIVE: To examine the prevalence and clinical manifestations of segmental motor paralysis after cervical laminoplasty and to investigate the presence of intramedullary high-signal intensity area (HIA) on postoperative T2-weighted magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: Almost all previous studies had been retrospectively conducted, and MRIs of all subjects, including a control population, have never been investigated. METHODS: In the 79 patients of the prospective group, the sole examiner evaluated muscle strengths daily for perioperative 3 weeks and MRI scans were performed before and after surgery. Medical records of the 79 consecutive patients before this study were also investigated (control group). RESULTS: Ten patients from the prospective group developed segmental motor paralysis (proximal in 5, distal in 2, and diffuse in 3), whereas paralysis occurred in only 4 patients from the control group (proximal in 3 and diffuse in 1). On postoperative MRI, a linear HIA corresponded to the paralyzed segment more frequently than a focal or no HIA. CONCLUSION: In the prospective cases, distal or diffuse paralysis was found more frequently than in the retrospective control group. Linear HIAs were significantly more likely to present in the paralyzed segments.