Disappearance of retro-odontoid pseudotumor after C1-C2 transarticular fixation screw

Atlantoaxial degenerative articular cysts are described in various situations like rheumatoid arthritis, dialysis, and fractures... and in the C1-C2 subluxations of degenerative origin. The treatment of these retro-odontoid tumors does not consist in excision of the pseudotumor but in the reduction of instability by cervical fusion. The procedures are varied and comprise neurological and vascular risks. We report a case of C1-C2 subluxation associated with a pseudocyst compressing the cervical spinal cord, which was treated successfully by transarticular screwing without wiring procedure. This technique has never been used previously in this indication. However, the peroperational risks are less important and the results are similar to those of the other procedures.     

Virtual placement of posterior C1-C2 transarticular screw fixation

We wanted to evaluate how often safe and effective posterior C1-C2 transarticular screw placement is realizable when it is performed according to guidelines given in the literature. In 50 adult patients, computerized tomography scan data from C0 to C3 were transformed into a 3D spine model. Virtually, bilateral screws were placed from the medial third of the C2-C3 facet joint towards the rim of the C1 anterior arc parallel to midline. Three categories of virtual screw position were rated: optimal (virtual screw inside the C2 pars interarticularis, transversing the middle third of the atlantoaxial joint, and sparing the vertebral artery canal), suboptimal (virtual screw violating the C2 pars interarticularis, and/or transversing the lower or upper third of the C1-C2 joint, and sparing vertebral artery canal), and unacceptable (virtual screw breaching the vertebral artery canal). Optimal placement was seen in 74, suboptimal placement in 11, and unacceptable locations in 15 sites. We conclude that due to the variability of the anatomy of the upper cervical spine, optimal transarticular C1-C2 screw placement is not possible in up to 26%, and even hazardous in up to 15%. This paper was presented in part at the Jahrestagung der Deutschen Gesellschaft für Neurochirurgie, May 25–28, 2003, Saarbrücken, Germany     

C1-C2 intra-articular screw fixation for atlantoaxial posterior stabilization

STUDY DESIGN: A trial of a new posterior stabilization technique for atlantoaxial instability and a report of preliminary results. OBJECTIVES: To describe a new posterior stabilization technique for atlantoxial instability. SUMMARY OF BACKGROUND DATA: Magerl's transarticular screw fixation is an accepted technique for rigid atlantoaxial stabilization, which reportedly has yielded many good clinical results. However, the technique is technically demanding and poses a risk of injury to the nerves and veins. METHODS: Eleven patients who had been treated with intra-articular screw fixation in combination with Halifax interlaminar clamp (OSTEONICS, Allendale, NJ) for atlantoaxial instability were observed. Results of their clinical examinations and biomechanical studies using resinous bones of a cervical spine model were reviewed. RESULTS: In all patients, occipital pain, neck pain, and neural deficit improved, and bony fusion with no correction loss was shown on radiography. To date, no vascular or neural complications have been found, and no instrumentation failures have occurred. In the biomechanical study, the Halifax with transarticular screw fixation had significantly greater flexion stiffness than the Halifax only or the Halifax with intra-articular screw fixation, but the torsion stiffness of the Halifax with intra-articular screw fixation was significantly greater than that of the other Halifax combinations. CONCLUSION: The preliminary results showed that this technique was effective in strengthening the rotational stability of the atlantoaxial fixation and was considered useful for atlantoaxial posterior stabilization.     

后路经侧块关节螺钉内固定技术治疗寰枢椎不稳

目的：评价Magerl法内固定治疗寰枢椎不稳或脱位的临床疗效。方法：寰枢椎不稳14例,男10例,女4例;年龄17～62岁,平均38.6岁。均实施后路复位,Magerl法经关节螺钉内固定和自体髂骨植骨。结果：14例患者共植入经关节螺钉28枚。所有患者获随访,时间9～35个月,平均16个月,术后JOA评分13.8～15.8分,平均（14.50±0.66）分。改善率平均（76.12±4.94）%。术后无椎动脉和脊髓损伤发生,植骨全部融合。结论：Magerl法固定是治疗寰枢椎不稳的良好方法之一,无须加用结构性植骨和辅助内固定,自体颗粒状松质骨植骨即可实现有效的骨性融合。     

C1-C2 transarticular screw fixation: technical aspects.

OBJECTIVE: I review posterior atlantoaxial fusion with transarticular screw fixation, including indications, complications, and operative technique, emphasizing my experience. METHODS: The indications for C1-C2 transarticular screw fixation include traumatic injuries to the atlantoaxial complex, instability resulting from inflammatory disease (rheumatoid arthritis), and congenital abnormalities (os odontoideum). All patients underwent stabilization using cannulated C1-C2 transfacetal screws by the method described by Magerl. Supplemental interspinous fusion with bicortical autologous iliac crest graft and titanium cable was used to restore the posterior tension band by use of the method described by Sonntag's group. Preoperatively, all patients underwent imaging with plain radiographs, magnetic resonance imaging, and axial computed tomography. Patients were maintained in a rigid cervical orthosis postoperatively. RESULTS: Measures used to improve safety and efficacy include patient positioning, fluoroscopic guidance, preoperative magnetic resonance imaging, axial computed tomography, and open reduction of C1-C2 subluxation before screw passage. In this series of 75 patients, fusion was obtained in 72 patients (96%). There were no instances of vertebral artery injury, errant screw placement, instrumentation failure, dural laceration, spinal cord injury, or hypoglossal nerve injury. CONCLUSION: C1-C2 transarticular screw fixation with a posterior tension band construct provides excellent fusion rates with few perioperative complications. Preoperative imaging and meticulous surgical technique improve outcomes.     

寰枢椎椎弓根螺钉固定融合技术治疗寰枢椎不稳

目的 探讨应用寰枢椎椎弓根螺钉固定技术治疗寰枢椎不稳的疗效.方法 对2003年6月至2009年3月收治的21例寰枢椎不稳患者应用寰枢椎椎弓根螺钉技术治疗,男14例,女7例;年龄28～66岁,平均42.5岁.齿状突骨折10例,先天性游离齿状突4例,Jefferson骨折合并齿状突骨折3例,类风湿关节炎致寰枢椎不稳4例.所有患者均伴有寰枢椎半脱位或失稳.患者术前JOA评分4～14分,平均9.1分.结果 21例患者共置入寰枢椎螺钉84枚,无一例患者发生脊髓、神经根和椎动脉损伤.术中均未发生椎动脉和脊髓损伤,有5例出现静脉丛出血.所有患者均获随访,时间6～48个月,平均16个月.术后JOA评分11～17分,平均15.9分,平均改善率为85.1%.骨折的齿状突均完全愈合,植骨块全部融化,无内固定断裂和松动.结论 寰枢椎椎弓根螺钉固定技术是治疗寰枢椎失稳的有效方法,具有固定牢靠、短节段固定,操作相对安全方便、融合率高等优点.     

寰枢椎椎弓根螺钉固定融合技术治疗寰枢椎不稳

目的 探讨应用寰枢椎椎弓根螺钉固定技术治疗寰枢椎不稳的疗效.方法 对2003年6月至2009年3月收治的21例寰枢椎不稳患者应用寰枢椎椎弓根螺钉技术治疗,男14例,女7例;年龄28～66岁,平均42.5岁.齿状突骨折10例,先天性游离齿状突4例,Jefferson骨折合并齿状突骨折3例,类风湿关节炎致寰枢椎不稳4例.所有患者均伴有寰枢椎半脱位或失稳.患者术前JOA评分4～14分,平均9.1分.结果 21例患者共置入寰枢椎螺钉84枚,无一例患者发生脊髓、神经根和椎动脉损伤.术中均未发生椎动脉和脊髓损伤,有5例出现静脉丛出血.所有患者均获随访,时间6～48个月,平均16个月.术后JOA评分11～17分,平均15.9分,平均改善率为85.1%.骨折的齿状突均完全愈合,植骨块全部融化,无内固定断裂和松动.结论 寰枢椎椎弓根螺钉固定技术是治疗寰枢椎失稳的有效方法,具有固定牢靠、短节段固定,操作相对安全方便、融合率高等优点.     

寰枢椎椎弓根螺钉固定融合技术治疗寰枢椎不稳

目的 探讨应用寰枢椎椎弓根螺钉固定技术治疗寰枢椎不稳的疗效.方法 对2003年6月至2009年3月收治的21例寰枢椎不稳患者应用寰枢椎椎弓根螺钉技术治疗,男14例,女7例;年龄28～66岁,平均42.5岁.齿状突骨折10例,先天性游离齿状突4例,Jefferson骨折合并齿状突骨折3例,类风湿关节炎致寰枢椎不稳4例.所有患者均伴有寰枢椎半脱位或失稳.患者术前JOA评分4～14分,平均9.1分.结果 21例患者共置入寰枢椎螺钉84枚,无一例患者发生脊髓、神经根和椎动脉损伤.术中均未发生椎动脉和脊髓损伤,有5例出现静脉丛出血.所有患者均获随访,时间6～48个月,平均16个月.术后JOA评分11～17分,平均15.9分,平均改善率为85.1%.骨折的齿状突均完全愈合,植骨块全部融化,无内固定断裂和松动.结论 寰枢椎椎弓根螺钉固定技术是治疗寰枢椎失稳的有效方法,具有固定牢靠、短节段固定,操作相对安全方便、融合率高等优点.     

改良枢椎椎板螺钉联合寰椎侧块螺钉固定治疗齿状突骨折1例报告

枢椎经椎板螺钉固定不仅操作简单,而且固定牢固,近年来受到临床医生的广泛关注。但椎板螺钉有置入椎管的风险,而且对于椎板薄小的病例不宜使用[1~3]。枢椎具有颈椎中最为宽厚的棘突,我们以棘突基底部为螺钉钉道主要把持部分,将螺钉由棘突基底部置入,进入枢椎椎板后,由椎板中上端出钉,钉尖穿出椎板背侧皮质骨,形成枢椎棘突椎板螺钉固定（C2 spinous process laminar screw）,既达到了双层皮质骨固定,又可保证螺钉没有置入椎管的风险[4]。我们对1例枢椎椎板厚度不宜进行椎板螺钉固定的Anderson Ⅱ型齿状突骨折患者进行了枢椎棘突椎板螺钉联合寰椎侧块螺钉固定,临床疗效满意,报道如下。     

Technic of C1-C2 fixation by posterior screwing

A posterior screw fixation technique for C1-C2 is described which respects strict anatomical relations and allows associated posterior arthrodesis limited to C1-C2, using a single approach route. This method of posterior fixation can be used even when anomalies of the posterior arch of C1 or C2 exist, of whatever origin, as well as in the presence of a laminectomy. Four patients were operated upon using this method without any postoperative complications.     

Posterior C1-C2 fusion with polyaxial screw and rod fixation.

STUDY DESIGN: A novel technique of atlantoaxial stabilization using individual fixation of the C1 lateral mass and the C2 pedicle with minipolyaxial screws and rods is described. In addition, the initial results of this technique on 37 patients are described. OBJECTIVES: To describe the technique and the initial clinical and radiographic results for posterior C1-C2 fixation with a new implant system. SUMMARY OF BACKGROUND DATA: Stabilization of the atlantoaxial complex is a challenging procedure because of the unique anatomy of this region. Fixation by transarticular screws combined with posterior wiring and structural bone grafting leads to excellent fusion rates. The technique is technically demanding and has a potential risk of injury to the vertebral artery. In addition, this procedure cannot be used in the presence of fixed subluxation of C1 on C2 and in the case of an aberrant path of the vertebral artery. To address these limitations, a new technique of C1-C2 fixation has been developed: bilateral insertion of polyaxial-head screws in the lateral mass of C1 and through the pars interarticularis into the pedicle of C2, followed by a fluoroscopically controlled reduction maneuver and rod fixation. METHODS: After posterior exposure of the C1-C2 complex, the 3.5-mm polyaxial screws are inserted in the lateral masses of C1. Two polyaxial screws are then inserted into the pars interarticularis of C2. Drilling is guided by anatomic landmarks and fluoroscopy. If necessary, reduction of C1 onto C2 can be accomplished by manipulation of the implants, followed by fixation to the 3-mm rod. For definitive fusion, cancellous bone can be added. No structural bone graft or wiring is required. In selected cases, e.g., C1-C2 subluxation or fractures in young patients in whom only temporary fixation is necessary, the instrumentation can be removed after an appropriate time. Because the joint surfaces stay intact, the patient can regain motion in the C1-C2 joints. RESULTS: Thirty-seven patients underwent this procedure. No neural or vascular damage related to this technique has been observed. The early clinical and radiologic follow-up data indicate solid fusion in all patients. CONCLUSION: Fixation of the atlantoaxial complex using polyaxial-head screws and rods seems to be a reliable technique and should be considered an efficient alternative to the previously reported techniques.     

颈1-2关节突间隙螺钉固定融合治疗寰枢椎损伤及不稳

目的：探讨应用经C1－2关节突间隙螺钉固定技术治疗寰枢椎病变的可行性及临床疗效。方法：自2000年4月－2002年4月应用后路经C1－2关节突间隙螺钉内固定技术治疗C2双侧椎弓骨折3例，陈旧性齿状突骨折1例，寰枢椎不稳1例，观察术后寰枢椎的稳定性、植骨融合率及颈椎活动度。结果：5例病人术中无神经及血管损伤等并发症，术后即刻获得稳定，经4－20个月随访，均获得骨性愈合，螺钉无松动、退出及断裂，颈椎旋转活动度平均丧失35．72％。结论：经C1－2关节突间隙螺钉固定技术在治疗寰枢椎疾病中是安全有效的，为重建寰枢椎间稳定提供了一种新的内固定方法。     

Modification of C1-C2 transarticular screw fixation by image-guided surgery

STUDY DESIGN: This is a feasibility study of image-guided surgery for C1-C2 transarticular screw fixation comparing postoperative screw position in a nonrandomized prospective cohort with a historic control group in which fluoroscopic guidance was used alone. OBJECTIVES: To evaluate the potential benefits and disadvantages of image-guided surgery for C1-C2 screw placement. SUMMARY OF BACKGROUND DATA: C1-C2 transarticular screw fixation is biomechanically superior to other current surgical stabilization procedures. The original technique for C1-C2 screw placement relies on anatomic landmarks and intraoperative fluoroscopy. Screw misplacement or anatomic variations can result in vertebral artery injury. Image-guided surgery involves using computed tomography (CT) data to plan the optimal screw trajectory before surgery and then use this data to guide screw placement during the actual surgery. Promising results of this technique are reported in the literature, but no direct comparison between image-guided surgery and conventional surgical techniques has been previously reported. METHODS: The image-guided surgery group consisted of 37 prospective patients. The historic control group included 78 patients who had similar surgeries performed using only fluoroscopic guidance. For the image-guided surgery group, subluxation was reduced by positioning at the time of CT examination. The CT data were transferred to a StealthStation (Sofamor-Danek, Memphis, TN) surgical planning and guidance computer system, and an optimal screw trajectory was determined for the right and left transarticular screws. After matching the surgical field to the virtual computer field, C2 was drilled according to the planned screw trajectory, and screws were placed. Plain radiographs and CT were used for postoperative evaluation of the image-guided surgery group. RESULTS: Image-guided surgery reduced but did not eliminate the risk of screw misplacement. Surgical time was not increased overall. CONCLUSIONS: Image-guided surgery is an effective tool for the achievement of correct screw placement in C1-C2 transarticular screw fixation procedures. The procedure remains technically demanding.     

Transarticular atlanto-axial screw fixation for treatment of C1-C2 instability

Posterior transarticular screw fixation of the C1-C2 complex has become an accepted method of arthrodesis for patients requiring posterior C1-C2 fusion. Since 2000, four patients (2 males and 2 females) were treated with this surgical approach for management of atlantoaxial instability, including odontoid fracture with unilateral C1-C2 luxation, odontoid pseudarthrosis, complex congenital malformation of the craniovertebral junction and rheumatoid arthritis. All patients underwent stabilization with 2 transarticular C1-C2 screws, without any posterior interspinous graft. Patients were maintained in a rigid cervical orthesis 3 months postoperatively. Results were good, without any complication, after a short mean follow-up (8 months). Technical aspects of the technique are reported, The risk of screw malpositioning and vertebral artery or neural injury is minimal and can be lowered by using preoperative CT scan and MRI, and by using intraoperative fluoroscopy. Transarticular C1-C2 screw fixation proves to be a major surgical approach for treatment of atlantoaxial instability.     

后路寰枢椎椎弓根钉板固定融合治疗上颈椎不稳

目的 :探 讨寰 枢 椎椎 弓根 钉 板固 定融 合 治疗 上颈 椎 不稳 的可 行 性。 方法 :在 气管 插 管全 麻 下对 13 例 患者施 行了 寰 枢椎 椎弓 根 钉板 固定 术 ,并行 自 体髂 骨植 骨 。寰 椎椎 弓 根螺 钉的 进 钉点 位于 枢 椎侧 块中 线 上 ,距 寰椎后 弓上 缘 最少 3m m ,内斜 10° ,上斜 5°枢 椎椎 弓根 螺 钉的 进钉 点 位于 枢椎 侧 块内 上象 限 ,显 露枢 椎椎 弓 内缘 。直视 下进 钉 ,内斜 25°上斜 25° 螺 钉直 径 3.5m m ,寰 椎椎 弓 根螺 钉长 28￣32m m ,枢 椎椎 弓根 螺 钉长 24￣28m m 。 , 。结果 :全 组病 例未 发 生椎 动脉 、脊 髓 损伤 ,术 后临 床症 状 得到 不同 程 度的 改善 。随 访 3￣21 个月 ,平 均 6.7 个月 。 X线、CT 复查 示螺 钉 位置 良好 ,无 松动 、断 钉 ,植骨 3 个月 后均 达 到满 意融 合 。结 论 :寰 枢 椎 椎 弓根 钉 板 固 定治 疗上颈 椎不 稳 效果 良好 ,是 寰枢 椎 后路 固定 可 供选 择的 术 式之 一。     

Modified Gallie technique versus transarticular screw fixation in C1-C2 fusion

The effectiveness of a modified Gallie technique versus Magerl and Seeman transarticular screw fixation was compared in the management of 27 patients with symptomatic atlantoaxial instability. Twelve patients were treated using a modified Gallie technique and postoperative halo vest immobilization. Atlantoaxial arthrodesis occurred in seven (58%) patients, stable fibrous union occurred in one patient, and pseudarthrosis with recurrent instability developed in four (33%) patients. Average followup was 6.9 years. All 15 patients treated using Magerl and Seeman transarticular screw fixation and postoperative soft collar immobilization had atlantoaxial arthrodesis develop. Average duration of followup was 4 years. One patient sustained vertebral artery injury during preparation for screw placement. Magerl and Seeman transarticular screw fixation provides stability and more reliably produces atlantoaxial arthrodesis than the Gallie technique provides in patients with atlantoaxial instability without the need for rigid postoperative bracing. Potential for vertebral artery exists despite apparent accurate screw placement. To ensure that safe transarticular screw placement is possible, preoperative fine cut axial computed tomography with reconstructions is required to assess vertebral artery position and C2 isthmus anatomy. A proportion of patients have anatomy unsuitable for screw placement. Traditional wiring techniques are indicated in these patients.     

经骶1-2侧块螺钉固定的解剖学研究

目的:研究经骶1-2侧块螺钉固定的解剖学特征,探讨该技术的可行性。方法:对27例(男14例,女13例)骶尾椎CT资料进行三维重建,利用Advantage Workstation 4.2后处理工作站软件测量以第2骶后孔上缘上方5mm为进钉点的经骶1-2侧块螺钉(the sacral 1-2 translateral mass screw,STMS)固定的相关解剖学数据,包括:外倾角(从进钉点到骶骨翼最前上角的连线在水平面上与骶骨正中线的夹角)、上倾角(从进钉点到骶骨翼最前上角的连线与S1椎体上终板在矢状位上的夹角)及钉道长度(从进钉点到骶骨翼最前上角的距离)。对不同性别间及左右侧别间进行统计学分析。在三维图形上观察钉道轨迹,并根据上述测量数据在15例骶骨标本上置入STMS,观察螺钉与椎管、骶前后孔及耳状面关系。结果:平均外倾角男性为30.39°±5.01°,女性为35.81°±4.45°,男性左侧为31.14°±5.25°,右侧为29.64°±4.86°;女性左侧为36.46°±4.94°,右侧为35.15°±4.00°,性别间的差异有显著性意义(P<0.05),男性及女性的左右侧比较,差异无显著性意义(P>0.05)。平均上倾角男性为26.71°±16.50°,女性为19.48°±9.09°;左侧为23.67°±14.81°,右侧为22.22°±12.89°;平均钉道长度男性为54.48±3.01mm,女性为53.02±2.89mm;左侧为53.99±2.78mm,右侧为53.56±3.28mm。上倾角及钉道长度在性别及侧别间均无显著性差异(P>0.05)。在三维重建图形上观察钉道位于侧块内,置钉实验中STMS均未穿透至椎管、骶前后孔及耳状面。结论:在S1椎弓根螺钉不能提供有效固定的情况下,术前行CT三维测量以获得进钉参数,经骶1-2侧块螺钉固定技术可以安全的应用于骶骨固定。