The effect of head positions on the wake-up test in pedicle subtraction osteotomy for thoracolumbar kyphosis sencondary to ankylosing spondylitis

English Keywords:Ankylosing spondylitis  Pedicle subtraction osteotomy  Head positions  Wake-up test

English Abstract:

  【Abstract】 Objectives: To investigate the effect of different head positions on wake-up time and the quality of wake-up test in pedicle subtraction osteotomy(PSO) for thoracolumbar kyphosis caused by ankylosing spondylitis(AS). Methods: Between May 2005 and November 2012, 35 AS patients undergoing PSO were included in this study. Patients were divided into two groups: the head elevated group(elevated group) and the non-elevated group(non-elevated group). The same protocol of anesthesia, including the inducing and maintaining medications were applied for all patients. Bispectral index(BIS) was used to monitor the depth of anesthesia and to keep it consistent between the two groups. Wake-up time and the quality of wake-up (evaluated using a 3-point rank scale) were compared in these two groups. Results: Wake-up tests were successful in all cases. Patients in head elevated group had significantly shorter wake-up time compared with non-elevated group(24.9±5.13min vs 39.8±9.41min, P<0.05). During the wake-up tests, one patient in elevated group and five patients in non-elevated group suddenly opened their eyes with spontaneous limbs movement. For whom, the quality of wake-up test was the grade Ⅱ, whereas the remaining 29 patients were grade Ⅰ. The appearance of facial edema and chemosis in patients of elevated group was milder than non-elevated group. Conclusions: Elevating the head position can shorten wake-up time and improve the quality of wake-up test during the procedure of PSO for AS patients with thoracolumbar kyphosis.