Treatment of pediatric atlantoaxial instability with traditional and modified Goel–Harms fusion constructs

There are several treatment options for rigid fixation at C1–C2 including Brooks and Gallie type wired fusions and C1–2 transarticular screws. The use of a Goel–Harms type fusion, a construct with C1 lateral mass screws and C2 pedicle screws, has not been extensively described in pediatric patients. Here, we describe its relatively safe and effective use for treating pediatric patients by retrospective chart review of patients treated by the senior author for atlantoaxial instability with a Goel–Harms-type constructs during a 3-year period (2005–2007). Six patients were treated using Goel–Harms-type constructs. Five patients were treated utilizing a construct containing C1 lateral mass screws and C2 pedicle screws; one patient was treated using construct containing C1 lateral mass screws and C2 trans-laminar screws. The patients ranged in age from 7 to 17 years old (mean 12.7). All patients had findings of an os odontoideum on CT scans and three of the six patients had T2 hyperintensity on MRI. Three of the six patients presented with transient neurologic deficits: quadraplegia in two patients and paresthesias in two patients. In each patient C1 lateral mass and C2 screws were placed and the subluxation was reduced to attain an anatomical alignment. No bone grafts were harvested from the iliac crest or rib. Local morsalized bone and sub-occipital skull graft was used. All patients tolerated the procedure well and were discharged home on post-operative day 3–4. The patients wore a hard cervical collar and no halo-vests were needed. All patients had solid fusion constructs and normal alignment on post-operative imaging studies performed on average 14 months post-operatively (range: 7–29). The results demonstrated that Goel–Harms fusions are a relatively safe and effective method of treating pediatric patients with atlantoaxial instability and are not dependent on vertebral anatomy or an intact ring of C1. Follow-up visits and studies in this limited series of patients demonstrated solid fusion constructs and anatomical alignment in all patients treated.     

Subaxial subluxation after atlantoaxial transarticular screw fixation in rheumatoid patients

The most common cervical abnormality associated with rheumatoid arthritis (RA) is atlantoaxial subluxation, and atlantoaxial transarticular screw fixation has proved to be one of the most reliable, stable fixation techniques for treating atlantoaxial subluxation. Following C1–C2 fixation, however, subaxial subluxation reportedly can bring about neurological deterioration and require secondary operative interventions. Rheumatoid patients appear to have a higher risk, but there has been no systematic comparison between rheumatoid and non-rheumatoid patients. Contributing radiological factors to the subluxation have also not been evaluated. The objective of this study was to evaluate subaxial subluxation after atlantoaxial transarticular screw fixation in patients with and without RA and to find contributing factors. Forty-three patients who submitted to atlantoaxial transarticular screw fixation without any concomitant operation were followed up for more than 1 year. Subaxial subluxation and related radiological factors were evaluated by functional X-ray measurements. Statistical analyses showed that aggravations of subluxation of 2.5 mm or greater were more likely to occur in RA patients than in non-RA patients over an average of 4.2 years of follow-up, and postoperative subluxation occurred in the anterior direction in the upper cervical spine. X-ray evaluations revealed that such patients had a significantly smaller postoperative C2–C7 angle, and that the postoperative AA angle correlated negatively with this. Furthermore, anterior subluxation aggravation was significantly correlated with the perioperative atlantoaxial and C2–C7 angle changes, and these two changes were strongly correlated to each other. In conclusion, after atlantoaxial transarticular screw fixation, rheumatoid patients have a greater risk of developing subaxial subluxations. The increase of the atlantoaxial angel at the operation can lead to a decrease in the C2–C7 angle, followed by anterior subluxation of the upper cervical spine and possibly neurological deterioration.     

Bilateral C1 laminar hooks combined with C2 pedicle screws fixation for treatment of C1–C2 instability not suitable for placement of transarticular screws

The study design described here is a posterior C1–C2 fusion technique composed of bilateral C1 hooks and C2 pedicle screws. In addition, the clinical results of using this method on 13 patients with C1–C2 instability are reported. The objectives are to introduce a new technique for posterior C1–C2 fusion and to evaluate the clinical outcome of using it to treat C1–C2 instability. From October 2006 to August 2008, 13 patients (9 men and 4 women) with C1–C2 instability were included in this study: 3 had acute odontoid fractures, 4 had obsolete odontoid fractures, 4 had os odontoideum and 2 had traumatic rupture of the transverse ligament. All patients underwent posterior atlantoaxial fixation with bilateral C1 hooks and C2 pedicle screws. The mean follow-up duration was 25 months (range 13–30 months). Each patient underwent a complete cervical radiograph series, including anterior–posterior, lateral, and flexion–extension views, and a computed tomographic scan. The clinical course was evaluated according to the Frankel grading system. No clinically manifested injury of the nerve structures or the vertebral artery was observed in any of these cases. Five patients with neurological symptoms showed significant improvement in neurological function postoperatively. Bony fusion and construction stability were observed in all 13 patients (100%) on their follow-up radiographs, and no instrument failure was observed. Bilateral C1 hooks combined with C2 pedicle screws can be used as an alternative treatment method for C1–C2 dislocation, especially in cases not suitable for the use of transarticular screws. The clinical follow-up shows that this technique is a safe and effective method of treatment.     

寰枢椎椎弓根螺钉术中复位固定融合术治疗陈旧性齿状突骨折并寰枢椎脱位

目的:总结应用后路寰枢椎椎弓根螺钉术中提拉复位固定植骨融合术治疗陈旧性齿状突骨折并寰枢椎脱位的疗效。方法:2007年1月~2010年1月收治21例陈旧性齿状突骨折并寰枢椎脱位患者,男13例,女8例;年龄13~68岁,平均38.5岁。患者均有不同程度的枕颈部疼痛和活动受限,均伴有神经功能障碍,ASIA分级:B级2例,C级13例,D级6例;JOA评分4～14分,平均8.3分。根据Anderson和D′Alonzo分型,Ⅱ型骨折17例(81%),Ⅲ型骨折4例(19%)。MRI检查示18例患者有不同程度的脊髓受压,7例脊髓受压节段髓内出现T2加权像高信号改变。均为寰椎前脱位,术前均进行颅骨牵引术,15例(71.4%)可部分复位,6例(28.6%)不可复位。术前寰齿间距(atlanto-dens interval,ADI)9～15mm,平均12.3mm。均采用后路寰枢椎椎弓根螺钉术中提拉复位固定和植骨融合术,随访观察患者临床症状和神经功能改善情况,影像学检查寰枢椎复位和植骨融合情况。结果:患者均顺利完成手术,术中均未发生椎动脉和脊髓损伤。共置入84枚寰枢椎椎弓根螺钉,术后X线片及三维CT检查3枚寰椎椎弓根螺钉内倾角偏小,螺钉部分穿破椎动脉孔内侧壁,椎动脉造影未见椎动脉损伤;1枚寰椎椎弓根螺钉内倾角过大,螺钉部分穿破椎管内侧壁,未出现新的神经损伤症状;其余螺钉位置满意。术后颈椎CT及MRI显示寰枢椎序列重建满意,齿状突区域脑脊液线清晰,脊髓无压迫,ADI为2～4mm,平均2.8mm。患者均获随访,随访时间6～36个月,平均20个月,术后6个月随访时3例患者的ASIA分级无改变,其余患者的神经功能明显改善,ASIA分级:C级3例,D级10例,E级8例;JOA评分为10～17分,平均14.6分,平均改善率为81.2%。1例患者植骨块有部分吸收,其余患者均在术后6个月获得骨性融合,融合率为95.2%;随访期间未发现螺钉松动、移位、断裂和寰枢椎再移位、失稳现象。结论:应用寰枢椎椎弓根螺钉术中提拉复位技术治疗陈旧性齿突骨折并寰枢椎脱位可获得良好的临床效果。     

Computer-assisted Magerl's transarticular screw fixation for atlantoaxial subluxation

We report two patients with rheumatoid arthritis in whom posterior atlantoaxial fixation was carried out using transarticular screws with computer assistance. Two bilateral transarticular screws were inserted in one patient; however, in the other patient, only a unilateral screw was used, because computerized images showed that the vertebral artery at the other side was placed too medially to allow insertion of the screw. Neither of these patients had any neurovascular complications after surgery. Computer-assisted surgery is useful for avoiding neurovascular complications with transarticular screw fixation of C1-2. Received: January 26, 2001 / Accepted: August 13, 2001     

使用枢椎椎弓根螺钉和枕颈固定板的枕颈融合术

目的观察一种借助于枢椎椎弓根螺钉的枕颈固定装置治疗寰枢关节不稳定的效果。方法从2001年6月至2003年3月用自行设计的一套由椎弓根螺钉和枕颈固定板组成的枕颈固定器,治疗了38例寰枢关节不稳定的患者,其中24例有寰椎枕骨化。沿枢椎椎弓峡部的纵轴安置椎弓根螺钉,将枕颈固定板预弯后固定于枕骨,用螺母锁定固定板与椎弓根钉的过程中,利用固定板的曲度,使寰枢关节充分复位。植骨于枕骨与枢椎后弓间。结果36例获得了随访,平均18个月,均获得了骨性融合。没有神经、血管损伤和断钉、断板的病例。结论使用枢椎椎弓根螺钉和枕颈固定板的枕颈固定器不仅有可靠的、短节段固定作用,而且便于寰枢关节复位。     

前路经寰枢关节螺钉内固定术治疗寰枢关节不稳定的解剖学及临床研究

目的 为前路经寰枢关节螺钉内固定术提供临床解剖学依据.方法 在100对中国成人干燥寰、枢椎配对标本上,对与临床前路经寰枢关节螺钉内固定术相关的数据进行解剖学测量.并对11例创伤性寰枢椎不稳定患者施行了前路经寰枢关节螺钉内固定术,在齿状突与寰椎前结节后方置入颗粒状松质骨.结果 前路经寰枢关节螺钉内固定术冠状面上螺钉植入最小外偏角(5.5±2.0)度,最大外偏角(23.6±2.1)度,矢状面上螺钉植入最小后倾角(14.9±2.6)度,最大后倾角(25.6 ±2.5)度,内侧钉道距离(16.58±1.49)mm,外侧钉道距离(26.44±1.75)mln.11例患者中,1例颈脊髓完全损伤患者,术后1个月死于肺部感染.其余10例病例获得随访,时间7个月～3年,平均17个月,无椎动脉及脊髓损伤,所有病例获得骨性融合.结论 前路经寰枢关节螺钉内固定术,操作简便,损伤脊髓或椎动脉的风险较小,为寰枢椎不稳定患者提供了一种新的内固定治疗方法.     

经口咽寰枢椎侧块关节复位块状骨支撑植骨治疗颅底凹陷症并寰枢椎脱位

目的:探讨经口咽寰枢椎侧块关节牵开复位、三面皮质块状骨支撑植骨、内固定治疗颅底凹陷症合并寰枢椎脱位的价值.方法:2009年12月～2011年12月我院收治33例合并寰枢椎脱位的颅底凹陷症患者,均有脊髓压迫症状.术前寰齿间隙(ADI)3.8～12.1mm (7.9±3.9mm),齿状突顶部与Chamberlain线的垂直距离(DCL) 3.0～15.6mm (9.3±6.2mm),寰枢椎垂直脱位指数(VAAI)0.35～0.51 (0.46±0.07),颈髓延髓角(CMA)112°～145°(127°±13°),JOA评分7～10分.均采用经口咽寰枢椎侧块关节牵开复位、三面皮质块状髂骨支撑植骨、TARP内固定术治疗.记录手术时间、手术出血量等,观察并发症发生情况.术后随访8～23个月,平均11.5个月,复查影像学评价寰枢椎脱位复位和脊髓压迫改善情况,采用JOA评分改善率对脊髓功能改善情况进行评价,在CT扫描图像上观察螺钉位置及植骨融合情况.结果:手术时间110～185min (145±35min),出血量35～85ml(58±18ml).共置入寰椎侧块螺钉66枚,枢椎逆向椎弓根螺钉41枚,枢椎椎体螺钉25枚.术后钉道扫描显示,寰椎螺钉均位于侧块内,2枚逆向枢椎椎弓根螺钉偏外进入椎动脉孔,导致椎动脉孔闭塞,小脑缺血梗死,其余枢椎螺钉均无偏差.术后发生咽后壁感染1例,将钢板取出后改行后路手术获得愈合.术后CT重建图像显示陷入枕骨大孔的齿状突获得较理想复位,脊髓受压解除,ADI改善为0.2～4.5mm( 2.3±2.1 mm),VAAI改善为0.6～0.84(0.74±0.08),CMA改善为140°～178°(157°±15°),与术前比较均有显著性差异(P＜0.01).植骨块镶嵌在寰枢侧块关节间隙,术后6～11个月均获骨性愈合.术后患者肢体麻木、肌肉无力等症状均较术前有明显改善,术后3个月复查JOA评分恢复至13～16分(15.2±0.9分),末次随访时为13～17分(15.3±0.8分),与术前比较均有显著性差异(P＜0.01).结论:经口咽寰枢椎侧块关节牵开复位三面皮质块状髂骨支撑植骨内固定术是治疗颅颈交界区病变的有效方法,但有一定风险和难度,应在严格掌握手术适应证和严格围手术期处理的条件下合理应用.     

寰枢椎椎弓根螺钉固定技术在治疗寰枢椎不稳中的应用

目的 探讨寰枢椎椎弓根螺钉固定技术在寰枢椎不稳中的应用疗效.方法 2004年10月2008年12月,采用寰枢椎椎弓根螺钉固定技术治疗寰枢椎不稳12例,男7例,女5例,年龄26～62岁,平均49.4岁,其中枢椎齿状凸骨折5例,均为陈旧性AdersonⅡ型骨折;寰枢椎陈旧性脱位7例.所有患者均表现为枕颈区疼痛、颈部活动障碍.4例患者合并脊髓受压,Frankel分级C级和D级各2例.术前JOA评分5～12分,平均8.5分.术前均行颅骨牵引.寰椎进钉点在后结节中点旁18～20 mm与后弓下缘以上2 mm交点处,钉道方向与冠状面垂直,矢状面上头偏约5°,枢椎进钉点为下关节突内上象限,钉道方向内斜32°,上倾28°.结果 12例患者共植入寰、枢椎左右椎弓根螺钉各24枚,无一例发生脊髓或椎动脉损伤.所有患者均获成功随访,时间为6～48个月,平均25个月,术后6月JOA评分为13.5～16.7分,平均14.9分,改善率为87.4%.结论 寰枢椎椎弓根螺钉固定技术用于寰枢椎不稳的治疗中具有稳定固定的良好临床疗效.