Laminar screw fixation in the subaxial cervical spine: A report on three cases

Although laminar screw fixation is often used at the C2 and C7 levels, only few previous case reports have presented the use of laminar screws at the C3-C6 levels. Here, we report a novel fixation method involving the use of practical laminar screws in the subaxial spine. We used laminar screws in the subaxial cervical spine in two cases to prevent vertebral artery injury and in one case to minimize exposure of the lamina. This laminar screw technique was successful in all three cases with adequate spinal rigidity, which was achieved without complications. The use of laminar screws in the subaxial cervical spine is a useful option for posterior fusion of the cervical spine.     

下颈椎椎弓根螺钉内固定技术在临床中的应用

目的 :探讨下颈椎椎弓根螺钉内固定技术的临床应用。方法 :对2011年9月至2013年7月行下颈椎椎弓根螺钉内固定的32例患者进行回顾性分析,男20例,女12例;年龄21~78岁,平均56.4岁。其中10例为创伤性颈髓损伤,9例为颈椎管内肿瘤,7例颈椎后纵韧带骨化症,6例多节段颈椎病。所有患者术前行X线、CT、MRI及椎动脉MRA等影像学检查,术后及随访时行X线片及CT平扫明确螺钉的位置情况。根据Lee等4级分类法评价置钉的准确性,创伤性患者行ASIA分级评价脊髓功能变化,非创伤性患者采用JOA评分评价神经功能改善情况。结果:32例患者成功置入144枚下颈椎椎弓根螺钉,术后CT显示,0级132枚,1级5枚,2级5枚,3级2枚。有12枚螺钉穿破椎弓根,其中8枚螺钉穿破椎弓根外侧皮质,2枚螺钉穿破椎弓根下侧皮质,穿破椎弓根内侧、上侧皮质螺钉各1枚。术后随访12~33个月,平均(21.0±1.5)个月,6例完全性颈髓损伤患者术后神经功能虽无恢复,但截瘫平面下降1~3个脊髓节段。4例不完全性颈髓损伤患者术后按ASIA损伤分级提高1~2级。22例非创伤性患者术后6个月JOA评分平均(15.9±0.6)分,较术前(11.5±0.8)分明显提高(P<0.01)。所有患者未发现钉棒系统松动、断裂情况。结论:下颈椎椎弓根螺钉固定能提供优秀的三维稳定性。合理选择适应证,术前充分准备以及根据椎弓根形态个体化置钉可以最大限度的降低手术风险及手术并发症,值得临床应用推广。     

枢椎椎板螺钉在上颈椎后路固定术中的应用

目的探讨枢椎椎板螺钉固定术应用于上颈椎后路融合内固定术中的可行性。方法回顾性分析本院2012年1月—2014年12月在上颈椎后路融合固定术中采用枢椎椎板螺钉固定的19例患者资料,术中根据枢椎椎弓根是否存在缺如、细小等情况,选择置入双侧枢椎椎板螺钉或单侧枢椎椎板螺钉并对侧椎弓根螺钉,联合枕骨板螺钉和/或寰椎侧块螺钉。15例上颈椎畸形患者均有不同程度脊髓功能损害表现,日本骨科学会(JOA)评分为5~15分,平均11.5分。4例外伤性寰枢椎骨折患者有后颈部疼痛及活动障碍,疼痛视觉模拟量表(VAS)评分为2~7分,平均4.5分。术后复查患者影像学资料,观察内固定位置及植骨融合情况。结果所有手术顺利完成,未发生椎动脉、脊髓等损伤。术后复查CT,显示所有枢椎椎板螺钉位置良好,均未突破内侧皮质骨。随访时X线、CT示螺钉位置良好,无松动及断钉。所有患者术后12个月植骨均融合,上颈椎畸形患者神经功能均有不同程度改善,JOA评分为13~17分,平均15.3分。外伤性寰枢椎骨折患者颈部疼痛及活动障碍明显改善,VAS评分为0~2分,平均1.0分。结论枢椎椎板螺钉固定在上颈椎后路固定手术中方法简单安全、效果良好,对于无法行枢椎椎弓根螺钉固定的患者,枢椎椎板螺钉固定是一种安全有效的替代方法。     

颈椎后路双开门脊髓减压椎弓根内固定术治疗颈椎骨折脱位的效果分析

目的探讨颈椎后路双开门脊髓减压椎弓根内固定术治疗颈椎骨折脱位并脊髓损伤患者的治疗效果。方法2000年12月至2008年4月,行颈椎后路双开门脊髓减压椎弓根内固定术治疗38例颈椎骨折脱位并脊髓损伤患者,男28例,女10例;年龄20-80岁,平均43．5岁;颈椎损伤节段：C22例,C33例,C410例,C513例,C68例,C72例。术后行椎弓根螺钉CT检查并观察脊髓神经功能改善状况。结果38例患者C2-7共置入椎弓根螺钉158枚,其中152枚（96．2％）完全置入椎弓根皮质骨内,6枚（3．8％）置入位置不准确,包括进钉位置偏内经椎板进入椎管2枚,偏外挤穿椎弓根外侧皮质4枚。术后随访36例,随访时间1-36个月,平均6．8个月;脊髓神经损伤ASIA分类：A级7例、B级15例、C级13例、D级3例,A级的7例患者中5例感觉下降,恢复至B级;2例感觉完全恢复,上肢肌力有改善,但下肢运动功能无改善,分别恢复至C、D级。其余均有1-3级的功能恢复。无1例继发性血管、神经损伤。结论早期行后路双开门脊髓减压椎弓根内固定术以保持颈椎损伤阶段的稳定性,对颈椎骨折脱位并脊髓损伤患者的功能恢复有显著治疗作用。     

下颈椎前路椎弓根螺钉固定系统的设计与运用

目的：研究下颈椎前路椎弓根螺钉钢板系统运用的可行性,为临床使用提供依据。方法：对16具颈椎标本随机分割获得C3．4,C4加C5．6,C6,7各8个运动单元（functionalspinalunit,FSu）,共32个FSU。运用下颈椎前路椎弓根螺钉钢板系统模拟植入重建FSU稳定性。测量钢板螺钉与椎体之间的适应性,运用X线摄片及CT扫描及重建评估下颈椎前路椎弓根螺钉植入的准确性,对于穿破椎弓根的标本,解剖明确其累及周围组织的情况。结果：32个FSU共计植入下颈椎前路椎弓根螺钉64枚,所有螺钉均顺利植入,无术中植入困难者。螺钉植入后与钢板螺钉孔之间的匹配程度好,未见难以锁紧的情况。钢板与椎体之间适应性良好。X线片提示所有64枚下颈椎前路椎弓根螺钉植入位置满意,螺钉长短合适。CT横断位像提示共有6枚螺钉在下颈椎椎弓根穿出,2枚内侧皮质1度穿破,4枚1度外侧缘皮质穿破累及横突孔内侧缘,未见螺钉≥2度穿破椎弓根。2枚下颈椎前路椎弓根内侧皮质1度穿破的患者,解剖发现仅有椎管内椎弓根内侧的静脉丛累及,未见硬膜囊受压,未见神经根受累。4枚1度外侧缘穿破的患者有1枚横突孔内椎静脉的累及,未见椎动脉穿破累及的情况,但其中1枚螺钉紧换椎动脉而行。结论：下颈椎前路椎弓根螺钉钢板系统适应下颈椎前路椎弓根螺钉固定重建,有临床运用价值。     

单侧枢椎椎板螺钉在椎动脉变异的上颈椎不稳中的临床应用

目的：探讨后路寰椎侧块螺钉联合单侧枢椎椎板螺钉＋对侧枢椎椎弓根螺钉固定、自体双皮质骨加压植骨融合术治疗上颈椎不稳伴椎动脉变异的临床疗效。方法：2008年6月至2012年12月,行后路寰椎侧块螺钉联合单侧枢椎椎板螺钉＋对侧枢椎椎弓根螺钉固定、自体双皮质骨加压植骨融合术12例,男8例,女4例,年龄16—77岁,平均47．5岁。术前患者枕颈部活动受限伴或不伴疼痛,VAS评分0-7分,平均3．50±2．71;椎动脉造影或颈椎CTA示单侧椎动脉明显狭窄。观察术中有无神经及血管损伤;术后7d内行X线和CT检查,了解内固定位置;术后随访观察有无内固定松动、断裂失败并发症、复位丢失,以及植骨融合率等。结果：12例单侧枢椎椎板螺钉固定,术中未发生神经和椎动脉损伤。患者颈部VAS评分0．92±0．90,较术前明显减轻（P=0．01）。术后x线示12例患者颈椎序列恢复良好,CT示1例枢椎椎板腹侧皮质侵犯,余位置均良好。12例患者均获得随访,时间6个月～3年;未见内固定松动、断裂和复位丢失等并发症;术后6个月12例均骨性融合。结论：后路寰椎侧块螺钉联合单侧枢椎椎板螺钉＋对侧枢椎椎弓根螺钉固定、自体双皮质骨加压植骨融合术,既避免了传统螺钉固定椎动脉损伤的同时,又克服了部分病例双侧枢椎椎板螺钉时植骨床的不足,在保证良好力学稳定的情况下,可以取得良好的骨性融合率。单侧枢椎椎板螺钉可以作为一种安全有效的补充固定措施应用于椎动脉变异的上颈椎不稳患者中。     

枢椎椎板螺钉治疗上颈椎不稳的临床研究

目的探讨枢椎椎板螺钉技术的临床应用和适应证。方法2004年10月至2008年12月,采用后路枢椎椎板螺钉技术治疗上颈椎不稳35例,男19例,女16例;年龄23～73岁,平均45岁。AndersonⅡ型和Ⅲ型齿突骨折19例,寰椎横韧带断裂1例,先天性游离齿突并寰枢椎不稳2例,寰椎骨折合并寰枢椎不稳7例,不典型Hangman骨折并C2-3不稳1例,C2-3创伤性不稳5例。患者均采用颈椎后路Vertex钉棒系统固定。结果35例患者共置入枢椎椎板螺钉68枚,术中无一例发生脊髓和椎动脉损伤。患者均获得随访,随访时间6个月～4年,平均25.5个月。随访时X线片均未见明显颈椎不稳、内固定失败及螺钉松动退出。11例患者螺钉穿出椎板背侧,但无症状出现。结论枢椎后路经椎板螺钉技术固定牢固,操作简单,相对安全,特别适用于C2椎弓根发育异常或骨折不能采用椎弓跟固定的患者。     

组合枢椎椎板螺钉及经枢椎椎板关节突螺钉固定技术的临床应用

目的探讨组合枢椎椎板螺钉及经枢椎椎板关节突螺钉(TLFS)固定技术治疗颈椎损伤的可行性和应用价值。方法自2005年10月～2008年10月,采用枢椎椎板螺钉及经枢椎TLFS固定技术治疗颈椎损伤36例。结果本组获随访13~32个月,平均18个月。30例行自体髂骨植骨,6例行异体骨植骨,获得了良好的骨性愈合。术后CT示枢椎椎板螺钉及经枢椎TLFS位置良好,未侵犯椎管和脊髓。结论枢椎椎板螺钉及经枢椎TLFS固定技术不受C2横突孔中椎动脉的位置和C2椎弓根大小限制,避免了螺钉置入过程中损伤椎动脉的风险,所以该方法可作为传统枢椎后路螺钉固定技术的补充。     

Complications of pedicle screw fixation in reconstructive surgery of the cervical spine

STUDY DESIGN: Retrospective evaluation of complications in 180 consecutive patients with cervical disorders who had been treated by using pedicle screw fixation systems. OBJECTIVES: To determine the risks associated with pedicle screw fixation in the cervical spine and to emphasize the importance of preoperative planning and surgical techniques in reducing the risks of this procedure. SUMMARY OF BACKGROUND DATA: Generally, pedicle screw fixation in the cervical spine has been considered too risky for the neurovascular structures. There have been several reports describing the complications of lateral mass screw-plate fixation. However, no studies have examined in detail the complications associated with cervical pedicle screw fixation. METHODS: One hundred eighty patients who underwent cervical reconstructive surgery using cervical pedicle screw fixation were reviewed to clarify the complications associated with the pedicle screw fixation procedure. Cervical disorders were spinal injuries in 70 patients and nontraumatic lesions in 110 patients. Seven hundred twelve screws were inserted into the cervical pedicles, and the locations of 669 screws were radiologically evaluated. RESULTS: Injury of the vertebral artery occurred in one patient. The bleeding was stopped by bone wax, and no neurologic complication developed after surgery. On computed tomographic (CT) scan, 45 screws (6.7%) were found to penetrate the pedicle, and 2 of 45 screws caused radiculopathy. Besides these three neurovascular complications directly attributed to screw insertion, radiculopathy caused by iatrogenic foraminal stenosis from excessive reduction of the translational deformity was observed in one patient. CONCLUSIONS: The incidence of the clinically significant complications caused by pedicle screw insertion was low. Complications associated with cervical pedicle screw fixation can be minimized by sufficient preoperative imaging studies of the pedicles and strict control of screw insertion. Pedicle screw fixation is a useful procedure for reconstruction of the cervical spine in various kinds of disorders and can be performed safely.     

Complications of transpedicular screw fixation in the cervical spine

Today, posterior stabilization of the cervical spine is most frequently performed by lateral mass screws or spinous process wiring. These techniques do not always provide sufficient stability, and anterior fusion procedures are added secondarily. Recently, transpedicular screw fixation of the cervical spine has been introduced to provide a one-stage stable posterior fixation. The aim of the present prospective study is to examine if cervical pedicle screw fixation can be done by low risk and to identify potential risk factors associated with this technique. All patients stabilized by cervical transpedicular screw fixation between 1999 and 2002 were included. Cervical disorders included multisegmental degenerative instability with cervical myelopathy in 16 patients, segmental instability caused by rheumatoid arthritis in three, trauma in five and instability caused by infection in two patients. In most cases additional decompression of the spinal cord and bone graft placement were performed. Pre-operative and post-operative CT-scans (2-mm cuts) and plain X-rays served to determine changes in alignment and the position of the screws. Clinical outcome was assessed in all cases. Ninety-four cervical pedicle screws were implanted in 26 patients, most frequently at the C3 (26 screws) and C4 levels (19 screws). Radiologically 66 screws (70%) were placed correctly (maximal breach 1 mm) whereas 20 screws (21%) were misplaced with reduction of mechanical strength, slight narrowing of the vertebral artery canal (<25%) or the lateral recess without compression of neural structures. However, these misplacements were asymptomatic in all cases. Another eight screws (9%) had a critical breach. Four of them showed a narrowing of the vertebral artery canal of more then 25%, in all cases without vascular problems. Three screws passed through the intervertebral foramen, causing temporary paresis in one case and a new sensory loss in another. In the latter patient revision surgery was performed. The screw was loosened and had to be corrected. The only statistically significant risk factor was the level of surgery: all critical breaches were seen from C3 to C5. Percutaneous application of the screws reduced the risk for misplacement, although this finding was not statistically significant. There was also a remarkable learning curve. Instrumentation with cervical transpedicular screws results in very stable fixation. However, with the use of new techniques like percutaneous screw application or computerized image guidance there remains a risk for damaging nerve roots or the vertebral artery. This technique should be reserved for highly selected patients with clear indications and to highly experienced spine surgeons.     

下颈椎经关节螺钉钉棒系统形式固定的临床研究

目的:探讨下颈椎经颈后正中入路采用经关节螺钉钉棒形式固定的应用。方法:自2005年7月至2009年7月,在11例下颈椎创伤性骨折脱位,9例颈椎管狭窄的后路固定中应用经关节螺钉以Vertex钉棒系统形式固定。其中男16例,女4例;年龄29～76岁,平均51岁,均行颈椎后路经关节螺钉内固定植骨融合、减压(其中3例结合前路手术)。经关节螺钉置钉方法:以侧块中心点内侧1mm为进钉点,进钉角度在矢状面上尾倾35°～40°,在冠状面上外倾15°～20°。术后摄颈椎X线片,评价螺钉位置和颈椎的序列和植骨融合情况。结果:共置入经关节螺钉88枚,其中10枚于C3,4,20枚于C4,5,32枚于C5,6,26枚于C6,7。术中所有螺钉均成功置入,未出现椎动脉、神经根和脊髓损伤等置钉相关并发症且均获得植骨融合,无内固定断裂失败。JOA评分:术后1周平均改善率55.8%,其中优5例,良7例,可7例,差1例,优良率为60%;术后3个月平均改善率为74.5%,其中优6例,良8例,可6例,优良率75%。术前与术后3个月JOA评分比较有统计学差异。结论:后路经关节螺钉钉棒形式内固定是一种有效的下颈椎固定形式,经过初步临床应用发现具有固定可靠,操作简单等优点。但这一新的固定形式,尚需长期的临床随访和观察。     

椎弓根螺钉在颈胸段骨折脱位中的临床运用

目的：评价椎弓根螺钉技术在颈胸段骨折脱位（C6-T2）中的运用价值。方法：2001年5月至2008年1月运用椎弓根螺钉植入技术治疗颈胸段骨折脱位患者26例,男17,女9例;年龄20-75岁,平均48．5岁。采用单纯后路椎弓根螺钉技术17例,后路椎弓根螺钉技术结合前路减压钢板内固定9例。术后3d运用CT平扫及重建片观察评价植入颈胸段椎弓根螺钉的准确性、螺钉植入相关并发症;随访观察患者颈胸段术后植骨融合情况;统计患者术前与术后6个月JOA评分及ASIA分级改善情况,综合评价患者脊髓及神经功能改善情况。结果：所有患者获得随访,随访时间3～74个月,平均36．5个月。4例完全性瘫痪患者术后6个月内死亡。共计植入椎弓根螺钉104枚,其中颈椎椎弓根74螺钉枚（其中：C516枚,C616枚,C742枚）,胸椎椎弓根螺钉30枚（其中：T1 22枚,T28枚）,所有椎弓根螺钉在术中均成功植入,无脊髓、神经根及椎动脉损伤。术后CT提示颈椎椎弓根螺钉11枚（14．9％）穿破椎弓根,其中7枚（9．5％）穿破外侧皮质,1枚（1．4％）穿破椎弓根上侧皮质,3枚（4．1％）穿破椎弓根下侧皮质。胸椎椎弓根螺钉中,3枚（10％）穿破胸椎椎弓根,其中2枚（6．7％）穿出椎弓根外侧缘,1枚（3．3％）穿破内侧缘（〈2mm）,但无临床症状。术后随访1枚C,椎弓根螺钉断裂,但患者无明显临床症状,其余无螺钉松动及断钉情况出现。所有患者固定良好,并均达到骨性融合。术后6个月患者平均JOA评分由术前（7．5±2．0）分恢复到（14．5±2．3）分,差异有统计学意义（t=6．34,P〈0．05）。ASIA分级情况,除3例完全性瘫痪患者脊髓功能术后无明显改善外,余患者术后脊髓神经功能均有不同程度恢复。结论：椎弓根螺钉在颈胸段骨折脱位治疗中安全、可靠。术者应熟练掌握颈胸段后?     

Intra-osseous ultrasound for pedicle screw positioning in the subaxial cervical spine: an experimental study

Background  

In contrast to other regions of the human spine, dorsal fixation with rods and pedicle screws is comparatively rarely performed in the cervical spine. Although this technique provides a higher mechanical strength than the more frequently used lateral mass screws, many surgeons fear the relatively high rate of misplacements. This higher incidence is mainly due to the complex vertebral anatomy in this spinal segment. For correct screw placement, the availability of an immediate and efficient intra-operative imaging tool to ascertain the accuracy of the pedicle screw hole position would be beneficial. We have previously investigated the usefulness of an intraspinal, specifically, intra-osseous ultrasound technique in the lumbar spine. In this study its accuracy as a means of controlling intrapedicular screw hole positioning has been evaluated in the cervical spine.     

枢椎棘突螺钉与椎弓根螺钉的解剖学比较

目的：比较枢椎棘突螺钉和椎弓根螺钉的技术难度和相关解剖学参数,探讨枢椎棘突螺钉固定的可行性和安全性。方法：自2010年2月至7月,选取10具颈椎标本,男5具,女5具,年龄45～76岁,平均60.5岁。将标本俯卧,颈部置于中立位。从C1-C3剔除颈部后侧所有的软组织,以清楚地暴露枢椎侧块和峡部。枢椎椎体左右侧任意选择进行棘突螺钉和椎弓根螺钉固定,各10枚螺钉,置入直径为4.0mm的皮质骨螺钉。枢椎棘突螺钉以枢椎棘突螺钉的进钉点选择为棘突的基底部、棘突和椎板的交界处,进钉角度水平置钉,螺钉由对侧棘突基底部穿出,形成双层皮质固定;枢椎椎弓根螺钉进钉点为枢椎下关节突根部中点,钉道方向与矢状面夹角15°～20°,与横断面夹角约30°。螺钉置入后,使用多层螺旋CT扫描机对标本进行扫描重建。测量螺钉在骨内的实际深度,记录椎弓根螺钉和棘突螺钉置钉失败、穿破椎弓根、进入椎管或置入横突孔的螺钉数目。结果：枢椎棘突螺钉和椎弓根螺钉的置入均无明显的技术困难。棘突螺钉未见螺钉置入椎管和劈裂棘突,但椎弓根螺钉有1枚螺钉突出椎弓根外侧皮质,侵犯横突孔。枢椎棘突螺钉的平均钉道长度为（21.4±1.4）mm,稍短于枢椎椎弓根螺钉的（23.7±1.0）mm,但两者间差异无统计学意义（t=-4.387,P〉0.05）。结论：枢椎棘突基底部具有螺钉固定的可行性,枢椎棘突螺钉较椎弓根螺钉固定相对安全、简单。     

Radiological studies on the best entry point and trajectory of anterior cervical pedicle screw in the lower cervical spine

Objective

To explore the best entry point and trajectory of anterior cervical transpedicular screws in the lower cervical spine by radiological studies, and provide reference for clinical application.

Methods

Fifty patients were scanned by computed tomography and confirmed no obvious defect of the cervical spine. On horizontal axis, camber angle (α) and axial length (AL) were measured from C₃ to C₇. On sagittal view, the cranial or caudal angle (β) and sagittal length (SL) were also measured from C₃ to C₇. On the sagittal and horizontal planes vertebrae were respectively divided into four areas, ordered 1–4, on the anterior side of the pedicle. The areas and angles of pedicle intersect into the vertebral body were recorded. We inserted six anterior pedicle screws into the lower cervical spine of three patients by this technique.

Results

On transverse plane, camber angle (α) of C₃–C₅ increased gradually, while it decreased from C₅ to C₇. On sagittal view, C₃ and C₄ pedicles showed cranial tilting, while C₅ to C₇ were caudally tilted. AL and SL values increased gradually from C₃ to C₇. The number of the intersections of C₃–C₇ in each area was also different. Six pedicle screws of three cases were inserted into the lower cervical spine with proper placement and no complications.

Conclusion

Anterior transpedicular screw (ATPS) is a theoretically feasible option for internal fixation. The technique described in this paper was subsequently used in three patients without complication. Future improvement of ATPS insertion remains necessary for this technically demanding procedure.     

三维平板透视引导上颈椎椎弓根螺钉置入准确性及疗效分析

目的 评价在三维平板透视系统引导下应用上颈椎椎弓根螺钉内固定加植骨融合技术治疗上颈椎骨折的安全性和临床疗效。方法 回顾性分析自2012-06-2013-10我科收治的11例上颈椎骨折脱位病例,均在术中三维平板透视系统引导下采用上颈椎椎弓根螺钉短节段内固定加植骨融合技术进行手术治疗。结果 术后所有患者的颈椎稳定性均得到即刻恢复,44枚螺钉均在位良好,未发生脊髓及椎动脉损伤等任何与置钉相关的并发症,无螺钉断裂、松动。结论 在三维平板透视系统引导下经上颈椎椎弓根螺钉内固定加植骨融合技术治疗上颈椎骨折脱位,螺钉置入准确性高,有效防止置钉并发症,力学稳定性好,植骨融合率高,是上颈椎骨折后路固定术中理想的手术方式之一。     

Placement and complications of cervical pedicle screws in 144 cervical trauma patients using pedicle axis view techniques by fluoroscope

Cervical pedicle screw fixation is an effective procedure for stabilising an unstable motion segment; however, it has generally been considered too risky due to the potential for injury to neurovascular structures, such as the spinal cord, nerve roots or vertebral arteries. Since 1995, we have treated 144 unstable cervical injury patients with pedicle screws using a fluoroscopy-assisted pedicle axis view technique. The purpose of this study was to investigate the efficacy of this technique in accurately placing pedicle screws to treat unstable cervical injuries, and the ensuing clinical outcomes and complications. The accuracy of pedicle screw placement was postoperatively examined by axial computed tomography scans and oblique radiographs. Solid posterior bony fusion without secondary dislodgement was accomplished in 96% of all cases. Of the 620 cervical pedicle screws inserted, 57 (9.2%) demonstrated screw exposure (<50% of the screw outside the pedicle) and 24 (3.9%) demonstrated pedicle perforation (>50% of the screw outside the pedicle). There was one case in which a probe penetrated a vertebral artery without further complication and one case with transient radiculopathy. Pre- and postoperative tracheotomy was required in 20 (13.9%) of the 144 patients. However, the tracheotomies were easily performed, because those patients underwent posterior surgery alone without postoperative external fixation. The placement of cervical pedicle screws using a fluoroscopy-assisted pedicle axis view technique provided good clinical results and a few complications for unstable cervical injuries, but a careful surgical procedure was needed to safely insert the screws and more improvement in imaging and navigation system is expected.     

Management of fracture-dislocation of the lower cervical spine with the cervical pedicle screw system

INTRODUCTION

Usually, cervical pedicle screw fixation has been considered too risky for neurovascular structures. The purpose of this study was to investigate the method and efficacy of the cervical pedicle screw system for fracture-dislocation of the cervical spine because of its rigid fixation.

PATIENTS AND METHODS

A prospective study was conducted involving 48 patients with cervical spine fracture-dislocation who underwent cervical pedicle screw fixation surgery between January 2003 and January 2007. All patients had various degrees of cord injury, and they were classified according to the American Spinal Cord Injury Association (ASIA) Impairment Scale: 18 cases were grade A, 15 grade B, 10 grade C, and 5 grade D.

RESULTS

Six months after the operation, all patients had achieved solid bony fusion and stable fixation of the related segments. Thirty patients with incomplete spinal cord injury improved their ASIA Impairment Scale classification by 1 to 2 grades after the operation. Eighteen patients with complete spinal cord injury had no improvement in neural function. However, nerve root symptoms such as pain and numbness were alleviated to some extent.

CONCLUSIONS

The cervical pedicle screw system is an effective and reliable method for the restoration of cervical stability. Sufficient pre-operative imaging studies of the pedicles and strict screw insertion technique should be emphasised.     

Computer-assisted posterior instrumentation of the cervical and cervico-thoracic spine

Posterior instrumentation of the cervical spine has become increasingly popular in recent years. Dissatisfaction with lateral mass fixation, especially at the cervico-thoracic junction, has led spine surgeons to use pedicle screws. The improved biomechanical stability of pedicle screws and transarticular C1/2 screws allows for shorter instrumentations and improves the repositioning possibilities. Nevertheless, there are potential risks of iatrogenic damage to the spinal cord, nerve roots or the vertebral artery with both techniques. Therefore, the aim of this study was to evaluate whether C1/2 transarticular screws and transpedicular screws can be applied safely and with high accuracy in the cervical spine and the cervico-thoracic junction using a computer-assisted surgery system (CAS system). Posterior instrumentation was performed using the Brainlab VectorVision System (BrainLAB , Heimstetten, Germany) in 19 patients. Surface matching was used for registration. We placed 22 transarticular screws C1/2, 31 cervical pedicle screws, 10 high thoracic pedicle screws and one lateral mass screw C1. The screw position was evaluated postoperatively using CT with multiplanar reconstruction in the screw axis of each screw. None of the transarticular screws or pedicle screws was significantly (>2 mm) misplaced and no screw-related injury to vascular, neurogenic or bony structures was observed. No screw revision was necessary. The mean operation time was 144 min (90–240 min) and the mean blood loss was 234 ml (50–800 ml). C1/2 transarticular screws, as well as transpedicular screws in the cervical spine and the cervico-thoracic junction, can be applied safely and with high accuracy using a CAS system. Computer-assisted instrumentation is recommended especially for pedicle screws at C3–C6.     

上颈椎失稳并脊髓不全损伤的外科治疗

目的讨论上颈椎失稳并脊髓不全损伤的诊断和治疗方法。方法男116例，女76例，平均年龄41岁。齿突骨折47例(新鲜骨折38例，陈旧性骨折9例)，Hangman骨折45例(新鲜骨折28例，陈旧性骨折17例)，寰椎横韧带断裂24例，先天畸形23例，寰椎单侧椎弓骨折19例，类风湿性关节炎17例，一侧关节凸骨折9例，Jefferson骨折并慢性不稳3例，肿瘤4例。齿突螺钉固定29例，颈2-3椎间融合10例，寰枢椎Apofix固定融合27例，颈枕融合Axis固定29例、Cervifix固定36例，Simmos寰枢固定融合32例，Brooks固定融合8例，钢丝加关节突螺钉固定8例：经椎弓根加压螺钉固定，植骨融合4例，其他方法1例。结果平均随访4年9个月。189例获得骨性愈合，延迟愈合3例，钢丝断裂2例，椎体移位1例。椎动脉损伤6例次，神经根损伤12例次，退钉10枚。JOA改善率79．9％，无脊髓损伤加重者。结论恰当的手术方法是治疗的基础，内固定物的选择可减少并发症.