目的:研究枢椎椎弓根关节突复合体的解剖结构特征,探讨该解剖概念的临床意义。方法:观察80具枢椎干骨标本椎弓根关节突部位的解剖结构特征。并随机抽取其中20具标本,在椎弓骨背侧表面做枢椎经椎弓根螺钉固定及经关节(C1-2)螺钉固定钉道投影画线,另2具标本按两种螺钉内固定方式设置直径3.5 mm钉道,并螺旋CT扫描多平面重建(MPR)钉道断面影像,了解两种钉道与椎弓根关节突结构的解剖关系。回顾性分析25例外伤致枢椎椎弓根关节突部位骨折的CT资料,包括其中12例枢椎螺钉内固定术后CT,研究该部位骨折特点及钉道所在的断面解剖。结果:枢椎解剖学上,无严格定义下完整的椎弓根。而枢椎椎弓根关节突作为复合体,具有解剖结构上整体性特征,其周围界线清楚。外伤致枢椎椎弓根关节突复合体骨折可分为椎弓根上关节突骨折、关节突间部骨折及单纯上关节突骨折。枢椎经椎弓根螺钉固定及经关节(C1-2)螺钉内固定的钉道均通过椎弓峡部中心,但起点不同,走向不同。结论:枢椎椎弓根关节突复合体作为临床解剖概念,具有解剖结构的完整性。明确该解剖概念及各构件对该区域骨折分类与螺钉内固定手术具有指导作用。
To study project of simpl icity and util ity for screw-plate system by pedicle of atlanto-axis mani pulatively hand by X-ray film and CT to prove the one success rate of putting screws. Methods Formulate personal program was used in operation by image save transmission of X-ray film and CT during January 2002 and September 2006 in 31 patients. There were 18 males and 13 femals, aged from 23 to 61 years old with an average age of 43.5 years. Putting screw points bypedicle of atlas were measured: left (19.93 ± 1.32) mm, right (19.16 ± 1.30) mm; putting screw obl iquity angle to inside by pedicle of atlas: left (23.72 ± 2.09)°, right (23.35 ± 1.91)°; putting screw obl iquity angle to side of head by pedicle of atlas: (9.00 ± 1.20)°. Screw points by pedicle of axis: left (13.14 ± 0.82) mm right (13.85 ± 0.79) mm; putting screw obl iquity angle to inside by pedicle of axis: left (24.52 ± 1.26)°, right (20.42 ± 1.42)°; putting screw obl iquity angle to side of head by pedicle of axis: (25.00 ± 3.00)°. The domestic location toward speculum was employed in operation and putting screw points and angles were formulated by X-CT program. The pedicle screws of suitable diameter and length were of exception and screws into pedicle of atlanto-axis were put by hand. Results Pain of the greater occipital nerve occurred in 2 patients after operation and was fully recovered by treatment 1 month after operation. The lateral cortical bone of pedicle was cut by 2 screws, but the spinal cord and vertebral artery were fine. The atlas and the fracture of odontoid process of axis were completely replaced in X-ray films of all patients 1 day after operation.The position relation of lag screw and vertebral artery or spinal cord was very good in CT sheets. All cases were followed up with an average of 10.5 months during 9 months to 5 years and 4 months, and obtained atlantoaxial arthrodesis. The breakage of screw and plate was not found in all cases. According to JOA score standard, 16 cases were excellent, 12 were good, 2 were fair, 1 was poor, and the excellent and good rate was 90.32% . Conclusion The personal design and cl inical appl ication of X-ray films and CT sheets are of great significance to screw-plate system by pedicle of atlanto-axis because of simpl ification of designs and methods and better personal ity.
ObjectiveTo evaluate the stability of the fixation technique for the crossed rods consisting of occipital plate and C2 bilateral lamina screws by biomechanical test.MethodsSix fresh cervical specimens were harvested and established an atlantoaxial instability model. The models were fixed with parallel rods and crossed rods after occipital plate and C2 bilateral laminae screws were implanted. The specimens were tested in the following sequence: atlantoaxial instability model (unstable model group), under parallel rods fixation (parallel fixation group), and under crossed rods fixation (cross fixation group). The range of motion (ROM) of the C0-2 segments were measured in flexion-extension, left/right lateral bending, and left/right axial rotation. After the test, X-ray film was taken to observe the internal fixator position.ResultsThe biomechanical test results showed that the ROMs in flexion-extension, left/right lateral bending, and left/right axial rotation were significantly lower in the cross fixation group and the parallel fixation group than in the unstable model group (P<0.05). There was no significant difference between the cross fixation group and the parallel fixation group in flexion-extension and left/right lateral bending (P>0.05). In the left/right axial rotation, the ROMs of the cross fixation group were significantly lower than those of the parallel fixation group (P<0.05). After the test, the X-ray film showed the good internal fixator position.ConclusionThe axial rotational stability of occipitocervical fusion can be further improved by crossed rods fixation when the occipital plate and C2 bilateral lamina screws are used.
目的:探讨后路寰枢椎椎弓根螺钉内固定的术前计划方案,明确其手术指导意义。方法:选取经CT评估寰枢椎椎弓根螺钉置入可行的,并拟选择该手术治疗的上颈椎不稳患者15例,容积再现重建(VR)寰枢椎椎弓表面影像,了解个体椎弓后方表面解剖形态与骨性解剖标志。同时按寰枢椎椎弓根理想的钉道走行,多平面重建(MPR)个体椎弓根断面影像。术前根据这些解剖影像设计手术暴露路经、理想的进钉点与钉道轨迹。术中按该术前计划手术暴露,找到理想的进钉点并钻孔置椎弓根螺钉。将术中观察到的C1后弓及C2椎弓表面解剖,与术前CT重建影像对比。术后CT复查,评价螺钉置入情况。结果:15例术中观察到的C1后弓及C2椎弓表面解剖特征与术前CT容积再现的影像一致。参照寰枢椎椎弓CT影像解剖制定术前计划方案,术中按其逐一操作,手术简单、直观,无重要血管神经损伤,置钉准确。结论:根据CT容积再现与多平面重建的寰枢椎解剖影像,制定后路寰枢椎椎弓根螺钉内固定术前计划方案,指导手术安全、可靠。
Objective To investigate the influence of axis pedicle and intra-axial vertebral artery (IAVA) alignment on C2 pedicle screw placement by measuring the data of head and neck CT angiography. MethodsThe axis pedicle diameter (D), isthmus height (H), isthmus thickness (T), and IAVA alignment types were measured in 116 patients (232 sides) who underwent head and neck CT angiography examinations between January 2020 and June 2020. Defined the IAVA offset direction by referencing the vertical line through the center of C3 transverse foramen on the coronal scan, it was divided into lateral (L), neutral (N), and medial (M). Defined the IAVA high-riding degree by referencing the horizontal line through the outlet of the C2 transverse foramen, it was divided into below (B), within (W), and above (A). The rate of pedicle stenosis, high-riding vertebral artery, and different IAVA types were calculated, and their relationships were analysed. Simulative C2 pedicle screws were implanted by Mimics 19.0 software, and the interrelation among the rates of pedicle stenosis, high-riding vertebral artery, IAVA types, and vertebral artery injury were analyzed. ResultsThe rate of C2 pedicle stenosis was 33.6% (78/232), and the rate of high-riding vertebral artery was 35.3% (82/232). According to the offset direction and the degree of riding, IAVA was divided into 9 types, among which the N-W type (29.3%) was the most, followed by the L-W type (19.0%) and the L-B type (12.9%), accounting for 60.9%. The vertebral artery injury rate of simulative implanted C2 pedicle screws was 35.3% (82/232). The vertebral artery injury rate in patients with pedicle stenosis and high-riding vertebral artery was significantly higher than that who were not (P<0.001). The rate of pedicle stenosis, high-riding vertebral artery, and vertebral artery injury were significantly different among IAVA types (P<0.001), and M-A type was the most common. ConclusionVertebral artery injury is more common in pedicle stenosis and/or high-riding vertebral artery and/or IAVA M-A type. Preoperative head and neck CT angiography examination has clinical guiding significance.
To cure patients suffering from atlanto-axial instability following old fracture of odontoid process concomitant with stenosis of lower end of cervical spinal canal, a new operative method was designed. It included atlanto-axial fusion by Gallie technique and resection of right half of the laminae of C3-C7 spine at one stage. A female of 63 years old was treated. She was admitted with neck pain and numbness of the upper and lower limbs. A history of neck injury was noted in enquiry. In physical examination showed the sensation of pain of the upper limbs was decreased and the muscle power of the upper and lower limbs ranged from III degree to IV degree. The X-ray film and MRI suggested that there was instability of the atlanto-axial joint with stenosis of 4th-6th cervical spinal canal. The operation was satisfactory. After operation, the patient was followed up for 11 months. The physical examination indicated that sensation of the upper limbs had recovered to normal and the muscle power of the upper limbs reached IV degree and that the lower limbs reached V degree and X-ray showed bony fusion of the atlanto-axial joint. The conclusions were: 1. The stability of atlanto-axial joint was reconstructed with expanding of the spinal canal at the same time. 2. The duration, risk and cost of the therapy were reduced, and maintenance of the stability of the cervical spine throughout whole period of treatment was recommended.
Objective To explore the effectiveness of fixation of atlas translaminar screws in the treatment of atlatoaxial instability. Methods A retrospective analysis was made on the clinical data of 32 patients with atlatoaxial instability treated with atlantoaxial trans-pedicle screws between March 2007 and August 2009. Of them, 7 patients underwent atlas translaminar screws combined with axis transpedicle screws fixation because of fracture types, anatomic variation, and intraoperative reason, including 5 males and 2 females with an average age of 48.2 years (range, 35-69 years). A total of 9 translaminar screws were inserted. Injury was caused by traffic accident in 4 cases, falling from height in 2 cases, and crushing in 1 case. Two cases had simple odontoid fracture (Anderson type II), and 5 cases had odontoid fracture combined with other injuries (massa lateralis atlantis fracture in 2, atlantoaxial dislocation in 1, and Hangman fracture in 2). The interval between injury and operation was 4-9 days (mean, 6 days). The preoperative Japanese Orthopaedic Association (JOA) score was 8.29 ± 1.60. Results The X-ray films showed good position of the screws. Healing of incision by first intention was obtained, and no patient had injuries of the spinal cord injury, nerve root, and vertebral artery. Seven cases were followed up 9-26 months (mean, 14 months). Good bone fusion was observed at 8 months on average (range, 6-11 months). No loosening, displacement, and breakage of internal fixation, re-dislocation and instability of atlantoaxial joint, or penetrating of pedicle screw into the spinal canal and the spinal cord occurred. The JOA score was significantly improved to 15.29 ± 1.38 at 6 months after operation (t=32.078, P=0.000). Conclusion Atlas translaminar screws fixation has the advantages of firm fixation, simple operating techniques, and relative safety, so it may be a remedial measure of atlatoaxial instability．
Objective To explore the feasibility and effectiveness of spinal pedicle screw internal fixation through endoscope-assisted posterior approach for the treatment of traumatic atlantoaxial instability. Methods Between September 2008 and September 2010, 44 patients with traumatic atlantoaxial instability received spinal pedicle screw internal fixation through endoscope-assisted posterior operation (micro-invasive surgical therapy group, n=22) or traditional surgical therapy (control group, n=22). There was no significant difference in gender, age, type of injury, disease duration, and preoperative Japanese Orthopedic Association (JOA) score between 2 groups (P gt; 0.05). The blood loss, operation time, length of the incision, improvement rate of JOA, and graft fusion rates were compared between 2 groups to assess the clinical outcomes. Results The blood loss, operation time, and length of the incision in the micro-invasive surgical therapy group were better than those in control group (P lt; 0.05). All incisions were primary healing. Of 88 pedicle screws, 7 pedicle screws penetrated into the interior walls of cervical transverse foramen in the micro-invasive surgical therapy group and 8 in the control group, but there was no syndrome of vertebral artery injury. All patients of the 2 groups were followed up 12 to 37 months (mean, 26 months). Bony fusion was achieved in all cases within 3 to 12 months (mean, 5.3 months). No loosening or breakage of screw occurred. At 6 months to 1 year after operation, the internal fixator was removed in 6 cases and the function of head and neck rotary movement were almost renewed. The JOA score was significantly improved at last follow-up when compared with preoperative score (P lt; 0.05), and no significant difference in JOA score and improvement rate between the 2 groups at last follow-up (P gt; 0.05). Conclusion The micro-invasive surgical therapy can acquire the same effectiveness to the traditional surgical therapy in immediate recovery of stability, high graft fusion rate, and less complication. Moreover, it can significantly reduce the operation time, blood loss, and soft tissue injury, so this approach may be an ideal way of internal fixation to treat traumatic atlantoaxial instability.
ObjectiveTo investigate the procedure and effectiveness of posterior approach for operation of atlantoaxial subdural extramedullary nerve sheath tumors.MethodsBetween January 2012 and March 2017, 9 patients with atlantoaxial subdural extramedullary nerve sheath tumors were treated, including 7 males and 2 females, aged 25-62 years (mean, 45.4 years). There were 8 cases of neurinoma and 1 case of neurofibroma. The tumors were located at C1 in 1 case and C1, 2 in 8 cases. The disease duration ranged from 5 to 120 months, with an average of 45.9 months. The neural function was rated as grade D in 8 cases and grade E in 1 case according to the American Spinal Injury Association (ASIA) grading system. The Japanese Orthopaedic Association (JOA) score was 12.8±2.5. All patients underwent posterior cervical surgery. The laminae were replanted and fixed in 2 cases. The atlantoaxial or occipitocervical axis was not fixed in all patients.ResultsThe operation time was 90-343 minutes, with an average of 179.2 minutes. The intraoperative blood loss was 50-1 000 mL, with an average of 335.6 mL. No relevant complication occurred after operation. All patients were followed up 6-21 months (mean, 11.1 months). The postoperative X-ray films showed the good stability of the cervical spine. All patients had complete tumor resection and no recurrence. The replanted laminae achieved fusion and the internal fixation was firm. According to ASIA grading system, 3 patients of preoperative ASIA grade D had upgraded to grade E at 3 months after operation, while the remaining patients had no change in grading. The JOA score was 15.1±1.4 at 6 months after operation, which was significantly improved when compared with that before operation (t=4.221, P=0.003).ConclusionThe atlantoaxial subdural extramedullary nerve sheath tumor (including the ventral tumor) can be removed completely via posterior approach. The axis lamina can be replanted and fixed with the small titanium plate or lamina screw when necessary, and the atlantoaxial or occipitocervical fixation was not needed.
ObjectiveTo investigate the accuracy of progressive three-dimensional navigation template system (abbreviated as progressive template) to assist atlas-axial pedicle screw placement. MethodsThe clinical data of 33 patients with atlas-axial posterior internal fixation surgery between May 2015 and May 2017 were retrospectively analyzed. According to the different methods of auxiliary screw placement, the patients were divided into trial group (19 cases, screw placement assisted by progressive template) and control group (14 cases, screw placement assisted by single navigation template system, abbreviated as initial navigation template). There was no significant difference in gender, age, cause of injury, damage segments, damage types, and preoperative Frankel classification between the two groups (P>0.05). The operation time and intraoperative blood loss of the two groups were compared. The safety of screw placement was evaluated on postoperative CT by using the method from Kawaguchi et al, the deviation of screw insertion point were calculated, the angular deviation of the nailing on coordinate systems XOZ, XOY, YOZ were calculated according to Peng’s method. ResultsAll patients completed the operation successfully; the operation time and intraoperative blood loss in the trial group were significantly less than those in the control group (t=–2.360, P=0.022; t=–3.006, P=0.004). All patients were followed up 12–40 months (mean, 25.3 months). There was no significant vascular injury or nerve injury aggravation. Postoperative immediate X-ray film and CT showed the dislocation was corrected. Postoperative immediate CT showed that all 76 screws were of grade 0 in the trial group, and the safety of screw placement was 100%; 51 screws were of grade 0, 3 of gradeⅠ, and 2 of gradeⅡ in the control group, and the safety of screw placement was 91.1%; there was significant difference in safety of screw placement between the two groups (χ2=7.050, P=0.030). The screw insertion point deviation and angular deviation of the nailing on XOY and YOZ planes in the trial group were significantly less than those in the control group (P<0.05). There was no significant difference in angular deviation of the nailing on XOZ between the two groups (t=1.060, P=0.290). ConclusionCompared with the initial navigation template, the progressive navigation template assisting atlas-axial pedicle screw placement to treat atlas-axial fracture with dislocation, can reduce operation time and intraoperative blood loss, improve the safety of screw placement, and match the preoperative design more accurately.