Objective: To evaluate the safety and efficacy of the combined use of ultrasonic bone curette with the high-speed drill in posterior laminectomy and decompression procedure for severe thoracic spinal stenosis, and propose the optimal cutting position for ultrasonic bone curette during the laminectomy. Methods: By observing and measuring the parameters of thoracic pedicle, lamina, inner wall of the vertebral canal and their relation with the surrounding structures on cadavers, we provided a morphological marker for laminectomy by an ultrasonic bone curette. Data of 19 patients with severe thoracic spinal stenosis treated by posterior laminectomy and decompression were collected from June 2017 to June 2018 in Shanghai Changzheng Hospital. There were 11 males and 8 females, aged (50±6) years. The patients received laminectomy with the combined use of ultrasonic bone curette and the high-speed drill (Group A, n=10) or the use of ultrasonic bone curette alone (Group B, n=9). Operational time of decompressive laminectomy, blood loss, as well as perioperative complications such as durotomy, cerebrospinal fluid leak, injury of the nerve root and spinal cord were recorded in these two groups. The improvement of symptoms and the decompression width of the spinal canal were evaluated after operation. Two independent samples t-test was used for the comparison of two sets of continuous normal distribution data. Results: We had done the measurement in 6 cadavers. The mean distance between the boundary of cancellous-cortical bone of lamina and the inner wall of spinal canal was (0.9±0.4) mm, and the distance between the boundary of cancellous-cortical bone of pedicle and the inner wall of the spinal canal was (1.2±0.6) mm. For the surgeries in groups A, the mean laminectomy time for each segment was (4.4±0.5) min, the mean width of posterior laminectomy was (21.8±0.5) mm; and for the surgeries in group B, the mean laminectomy time for each segment was (5.0±0.5) min, the mean width of posterior laminectomy was (19.9±1.0) mm; there were significant differences in laminectomy time for each segment and the width of posterior laminectomy between the two groups (t=-2.391, 3.491, both P<0.05). There was one case of dura injury and one case of thoracic nerve root injury during the operation in group B. Conclusions: It is safer and more reliable for the combined use of ultrasonic bone curette with the high-speed drill in posterior laminectomy and decompression procedure for the severe thoracic spinal stenosis. The interface between the cortical bone and the medial edge of cancellous bone of the pedicle could be identified as the cutting mark for ultrasonic bone curette in this procedure.
目的： 探讨超声骨刀联合高速磨钻在严重胸椎管狭窄症术中应用的有效性和安全性，并探寻超声骨刀切割的安全解剖学标志。 方法： 对胸椎标本的椎弓根，椎板与椎管内壁毗邻关系进行观测，为超声骨刀在骨槽内切割提供形态学参考。回顾性分析2017年6月至2018年6月在上海长征医院确诊并接受胸椎后路手术治疗的19例严重胸椎管狭窄症患者的病例资料。其中男11例，女8例，年龄（50±6）岁。术中分别采用超声骨刀联合高速磨钻（A组，n=10）及单纯超声骨刀方法（B组，n=9）进行椎管后壁切除减压术，术中记录两组术中椎管后壁切除及"揭盖"时间、出血量、有无神经根和脊髓损伤，术后评估症状改善及椎管后壁切除宽度。两组连续正态分布相关数据比较采用两独立样本t检验。 结果： 完成6具胸椎标本的测量，椎板松质骨与内侧皮质骨交界线距椎管内壁距离平均为（0.9±0.4）mm，椎弓根内侧皮质骨与松质骨界线与椎管内侧壁距离（1.2±0.6）mm。超声骨刀联合高速磨钻方法术中平均单节段切除用时（4.4±0.5）min，平均椎管后壁切除宽度为（21.8±0.5）mm；采用单纯超声骨刀平均用时（5.0±0.5）min，平均椎管后壁切除宽度为（19.9±1.0）mm，术中有1例脑脊液损伤及1例胸脊髓神经根损伤。两组单节段切割时间及椎管后壁切割宽度差异有统计学意义（t=-2.391、3.491，均P<0.05）。 结论： 对于严重胸椎管狭窄症手术，术中联合应用超声骨刀及高速磨钻方法具有一定优势；椎弓根内侧缘皮质骨与其松质骨交界区可以作为该方法的切割标志。.
Keywords: Anatomy; High-speed drills; Spinal stenosis; Thoracic vertebra; Ultrasonic bone curette.