Liu Zhen, Jin Mengran, Qiu Yong, Yan Huang, Han Xiao, Zhu Zezhang
From the Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Nanjing, China.
Medicine (Baltimore). 2016 May;95(18):e3581. doi: 10.1097/MD.0000000000003581.
To investigate the accuracy of O-arm navigation-assisted screw insertion in extremely small thoracic pedicles and to compare it with free-hand pedicle screw insertion in adolescent idiopathic scoliosis (AIS).A total of 344 pedicle screws were inserted in apical region (defined as 2 vertebrae above and below the apex each) of 46 AIS patients (age range 13-18 years) with O-arm navigation and 712 screws were inserted in 92 AIS patients (age range 11-17 years) with free-hand technique. According to the narrowest diameter orthogonal to the long axis of the pedicle on a trajectory entering the vertebral body on preoperative computed tomography, the pedicles were classified into large (>3 mm) and small (≤3 mm) subgroups. Furthermore, a subset of extremely small pedicles (≤2 mm in the narrowest diameter) was specifically discussed. Screw accuracy was categorized as grade 0: no perforation, grade 1: perforation by less than 2 mm, grade 2: perforation by 2 to 4 mm, grade 3: perforation over 4 mm.In the O-arm group, the mean thoracic pedicle diameters were 2.23 mm (range 0.7-2.9 mm) and 3.48 mm (3.1-7.1 mm) for small and large pedicles, respectively. In the free-hand group, the small and large thoracic pedicle diameters were 2.42 mm (range 0.6-2.9 mm) and 3.75 mm (3.1-6.9 mm), respectively. The overall accuracies of screw insertion in large and small thoracic pedicles (grade 0, 1) were significantly higher in O-arm group (large: 93.8%, 210/224, small: 91.7%, 110/120) than those of free-hand group (large: 84.9%, 353/416, small: 78.4%, 232/296) (P < 0.05). Importantly, the overall accuracy of screw placement in extremely small pedicles was significantly higher in the O-arm group (84.3%, 48/57) compared with 62.7% (79/126) in free-hand group (P < 0.05), and the incidence of medial perforation was significantly lower in O-arm group (11.1%, 1/9) compared with 17.0% (8/47) in free-hand group (P < 0.05).The O-arm intraoperative navigation system should be acknowledged for its superiority in scoliosis surgery, since it permits more accurate and safer instrumentation for AIS patients with small and extremely small thoracic pedicles.
研究O型臂导航辅助下在极小的胸椎椎弓根中置入螺钉的准确性，并将其与青少年特发性脊柱侧凸（AIS）患者徒手椎弓根螺钉置入进行比较。46例AIS患者（年龄范围13 - 18岁）在O型臂导航下于顶椎区域（定义为顶椎上下各2个椎体）共置入344枚椎弓根螺钉，92例AIS患者（年龄范围11 - 17岁）采用徒手技术共置入712枚螺钉。根据术前计算机断层扫描上进入椎体轨迹与椎弓根长轴正交的最窄直径，将椎弓根分为大（>3mm）和小（≤3mm）亚组。此外，还专门讨论了极小子组（最窄直径≤2mm）。螺钉准确性分为0级：无穿孔；1级：穿孔小于2mm；2级：穿孔2至4mm；3级：穿孔超过4mm。在O型臂组中，小椎弓根和大椎弓根的平均胸椎椎弓根直径分别为2.23mm（范围为0.7 - 2.9mm）和3.48mm（3.1 - 7.1mm）。在徒手组中，小和大胸椎椎弓根直径分别为2.42mm（范围为0.6 - 2.9mm）和3.75mm（3.1 - 6.9mm）。O型臂组大、小胸椎椎弓根螺钉置入的总体准确性（0级、1级）显著高于徒手组（大：93.8%，210/224；小：91.7%，110/120）（大：84.9%，353/416；小：78.4%，232/296）（P<0.05）。重要的是，O型臂组在极小子椎弓根中螺钉置入的总体准确性显著高于徒手组（84.3%，48/57），而徒手组为62.7%（79/126）（P<0.05），且O型臂组内侧穿孔的发生率显著低于徒手组（11.1%，1/9），徒手组为17.0%（8/47）（P<0.05）。O型臂术中导航系统在脊柱侧凸手术中的优越性应得到认可，因为它能为具有小和极小小胸椎椎弓根的AIS患者提供更准确、更安全的内固定。
