Axial computed tomography of the pedicle in the lower cervical spine

Using axial computed tomography (CT), we measured pedicle width, pedicle axis length, pedicle transverse angle, and distance between screw entry point and vertebrae midline in the cervical spines (C3-C7) of 40 patients. All measurements were greater in men than in women, and we noted significant sex differences at most levels of pedicle inner and outer widths (P < or = .05 or P < or = .01). Mean pedicle inner and outer widths for all levels and all patients ranged from 2.3 to 3.0 mm and from 5.0 to 6.0 mm, respectively. Mean distances between screw entry point and vertebrae midline ranged from 22.2 to 23.7 mm. Results of this study-along with axial CT measurements of individual pedicle diameter, pedicle transverse angle, and screw entry point-would be useful when considering and performing transpedicular screw fixation in the cervical spine.     

Measurement of effective pedicle diameter in the human spine

Effective pedicle diameter (EPD), the maximal cancellous diameter of the spinal pedicle, demonstrates the maximal diameter available for transpedicular screw placement. The pedicles of 16 spines from T6 to L5 were measured directly with a graduated mean increase in the EPD ranging from 4.8 mm at T6 to 5.9 mm at L5. This direct pedicle measurement was significantly smaller than that of previously reported studies, which directly and radiographically measured pedicle outside width rather than inner diameter. Three specimens had little, if any, pedicular medullary cavity on direct measurement, although radiographic appearance of a medullary cavity existed. If EPD is significantly smaller than radiographic pedicle width measurements, safe transpedicular screw fixation may not be achieved. Preoperative planning must account for this so that transpedicular screws of correct diameter may be used and the complications of pedicular blowout fracture and neurologic impairment may be avoided.     

Inter- and intraobserver variability in the postoperative evaluation of transpedicular stabilization: computed tomography versus magnetic resonance imaging

Background contextComputed tomography (CT) represents the state of the art for the postoperative verification of the implant position after transpedicular stabilizations. Magnetic resonance imaging (MRI) has not challenged the CT, yet, because of susceptibility artifacts but would be favorable as a diagnostic tool for its excellent soft-tissue qualities.PurposeA study that analyzed if an artifact-reduced MRI could overcome this problem and provide sufficient data for the postoperative assessment was conducted.Study designThe study design was a radiologic comparison of CT and MRI techniques evaluating pedicle screw placement after spinal fusion.Patient sampleFifty consecutive patients were given an MRI and a CT after a transpedicular stabilization surgery. Thirty-eight patients suffered from degenerative spinal disorders; three surgeries had become necessary because of spondylodiscitis, eight patients suffered from metastatic vertebrae destruction, and one patient experienced a fracture.Outcome measuresAny contact of a malpositioned pedicle screw with the dura and/or radicular structures was identified as an implant-associated complication and was compared with postoperative clinical patient findings.MethodsIn total, 338 pedicular screws were analyzed in regard to their intrapedicular position. The double-blind evaluation of MRI and CT data was carried out by two radiologists and two spine surgeons. Accuracy of the CT analysis was calculated based on the interobserver agreement of 100%. Magnetic resonance imaging accuracy was calculated.ResultsThe interobserver accuracy of the CT data amounted to a median of 89.8% and in the MRI data of 86.7%. Intraobserver comparisons showed a significant difference between CT and magnetic resonance evaluations in one observer (κ=0.293). In all other observers, the results were concordant with kappa values from κ=0.328 to κ=0.702. There was a high degree of agreement regarding the diagnosis of malpositioned pedicle screw and corresponding clinical symptoms between both techniques.ConclusionsThe presented data show that artifact-reduced MRI is equivalent to CT imaging in the postoperative evaluation of titanium spinal rod-screw systems. We therefore conclude that MRI should be considered as an alternative tool for the golden standard CT for postoperative imaging controls for its advantages in soft-tissue analysis.     

Verification of the position of pedicle screws in lumbar spinal fusion

Medial or lateral pedicle screw penetration with the potential to affect neural structures in a well-known and frequent problem associated with posterior spinal fusion. We evaluated the placement of pedicle screws (n = 141) in 36 patients following posterior lumbar spinal fusion with Socon or Kluger instrumentation via a lateral transpedicular approach. The examination was based on CT and MR images performed after removal of the instrumentation, on average 1 year after implantation. We found seven pedicle screws with lateral cortical penetration of the pedicle and five screws with medial cortical penetration of the pedicle (8.5% pedicle penetration overall). No severe radicular complications accompanied these pedicle penetrations. The mean insertion angles of the pedicle screws at the L4 level were 22.6° and 23.1° for the left and the right side, respectively. At the L5 level the mean insertion angle was 20.5° on the left side and 21.5° on the right, and at the S1 level the mean angle was 16.2° on the left and 15.2° on the right. The results of this study indicate that the lateral transpedicular approach is a safe procedure for pedicle screw insertion.     

管道疏通法行颈椎弓根螺钉置入的研究

目的：通过解剖学测量及临床应用探讨“管道疏通法”（dredging pipe method,DPM)对提高颈椎弓根螺钉置入的成功率、安全性及可操作性方面的应用价值。方法：（1）颈椎骨测量：成人C3－C7干燥骨42套，共210块椎骨，在实体及CT片上，测量椎骨的相关参数；92）临床应用：颈椎失稳症患者32例，术前X线、CT测量，参照标本及患者影像测量数据和管道疏通器自动寻迹的原理，个体化设计各椎节的置钉方案。在直视下显露椎弓根管口及其管腔，确定置钉方向和位置，扩孔攻丝置钉。术后观察对比相应指标，评价置钉的位置、方向。结果：91）与DPM相关的国人颈椎实体测量数据与CT测量数据比较无显著性差异（P＞0．05）；6．67％（28／42）椎弓根的宽度小于4mm;(2)32例患者共置入颈椎弓根钉146枚，术后CT复查96枚钉，其中5枚螺钉穿破椎弓根骨皮质，成功率94．8％。未出现神经血管损伤病例。结论：（1）术前影像学测量结果可人为个体化设计手术方案的重要依据，采用DPM置钉技术实施经颈椎弓根钉内固定手术，具有直视下操作、置钉准备率高、可操作性强等特点；（2）解剖学测量表明，极少部分人（6．67％）的C3－C7的椎弓根宽度不适宜做椎弓根钉内固定。     

Preoperative imaging of cervical pedicles: comparison of accuracy of oblique radiographs versus axial CT scans

In spite of concerns about safety during their insertion, cervical spine pedicle screws have demonstrated biomechanical superiority over lateral mass screws in several biomechanical studies. One of the concerns for placement of cervical pedicle screws is their small size. Preoperative planning with computed tomography to assess pedicle width has been shown to be extremely accurate and is recommended by several authors. To date there has been no study assessing the accuracy of oblique radiographs for pedicle measurement. We sought to compare accuracy of the oblique radiographic measurements of cervical pedicle width with axial CT scan measurements. Five fresh-frozen human cadaveric cervical spines C3–C7 were studied. Thin cut 1.25 mm computed tomography axial cuts were made through the pedicle isthmus. Oblique radiographs at 35°, 45°, and 55° angles were taken of the right and left pedicles of each specimen using a standardized technique. Each radiograph contained a pin of known length to correct for magnification. All pedicles were again measured and corrected for magnification using the standard pin. Corrected oblique radiograph measurements were compared to CT for each specimen. The outer pedicle width was measured and agreed upon by consensus. The radiograph measurements were on average significantly larger than CT measurements for the pedicles indicating that the pin standard did not completely correct magnification. Plain radiographic data failed to reveal that one oblique angle was favorable to another in terms of magnification or precision. Plain radiographs at oblique angles do not provide accurate measurements of subaxial cervical pedicles at 35°, 45°, or 55° angles. We recommend that thin cut axial CT scans be obtained on all patients prior to transpedicular fixation in the cervical spine. This research was supported by Evanston Northwestern Healthcare Medical Group Orthopaedic Faculty Practice Institutional funds.     

CT重建椎弓根轴线投影点定位研究

目的:建立椎弓根螺钉最佳入钉点,提高椎弓根螺钉内固定术的准确性和安全性。方法:高速螺旋CT共扫描检查40例国人的200个L1~L5脊椎。重建后测量400个椎弓根的入点坐标(x,y),即椎弓根轴线在椎骨后表面的投影点与后正中线的距离(x)及与横突中线的垂直距离(y)。结果:x坐标从L1~L5逐渐增大,男性大于女性(P<0.05);y坐标从L1到L4逐渐下移,在L4与横突中线接近重叠,但L5突然上升,与L2节段水平相当,L1~L5y坐标基本上都在横突中线以上,但每组数据变异较大。就y坐标而言,椎弓根轴线投影点与传统入点比较均有差异。结论:横突中线是椎弓根螺钉置入的重要参照标志,但椎弓根轴线投影点并不在横突中线上,不同个体、节段之间y坐标存在的较大差异是高误置率发生的重要原因。对个体而言,术前常规通过CT测量椎弓根轴线在椎骨后表面的投影点数据对椎弓根螺钉的置入有重要指导意义。     

颈椎斜位X线片在颈椎椎弓根钉固定中应用的研究

目的：探讨通过颈椎斜位X线片观察椎弓根的位置和方向,及其在判断椎弓根钉固定中准确,安全地进行钉的作用。方法：人尸体颈椎30例,其中椎动脉造影8例,椎动脉脊髓同时造影6例,根据术前X线斜位片,结合解剖标记定位,选择是钉点及进行钉方向,将直径3．5mm、长度24mm的不锈钢螺钉固定于C2或C3－C6或C7椎弓根中,共160枚,通过术后斜位X线片中判断螺钉在椎弓根的位置,并与CT扫描结果对照,以肯定X线的判断,结果：螺钉位置方向正确者152枚,X线片与CT扫描片的判断完全相符;X线判断螺钉偏向椎弓根外侧边缘5枚,偏向椎弓根内侧的边缘3枚。CT扫描确位于椎弓根外侧边缘3枚,怀疑进入椎动脉孔的2枚;在椎弓根内侧边缘没有进入椎管的3枚。结论：术前通过X线斜位片基本可以解椎弓根方向,上下径;通过术后X线斜位片可较为准确地判断椎弓根钉在椎弓根内的位置及有无进行推动脉孔、椎管的情况,X线与CT的结果差异可能与CT扫描的角度及其伪影有关,该方法简单易行。     

Rechnerunterstütztes Operieren in der Neurotraumatologie

In neurotraumatology, computer-assisted surgery is especially beneficial in spinal operations. With the aim of achieving an application accuracy of 2 mm or better, we used a mobile intraoperative CT system for data acquisition, the data being ascertained after temporary implantation of small titanium marker screws into the vertebrae. Between April 2000 and October 2000, 15 patients with spinal injuries were treated with 60 pedicle screws in vertebrae ranging from C7 to L3, with no positioning errors. Overall, we achieved a registration error (RSME) of 0.7±0.1 mm (SD). In our opinion, computer navigation is also indicated in neurotraumatology for the puncture of brain abscesses and the evacuation of intracerebral haematomas. In experiments with percutaneous navigation in a plastic model of the spine we achieved an application accuracy of 1.2±¶0.6 mm (SD) at the entry point of the pedicle and of 1.3±0.6 mm (SD) at the target point, with an registration-error of 0.9±0.19 mm (SD). Navigation in combination with intraoperative CT allows open and percutaneous operations at any level of the spine and makes it possible to perform an intraoperative quality check.     

经伤椎椎弓根椎体内植骨并植钉治疗胸腰椎骨折

目的探讨经伤椎椎弓根椎体内植骨并植钉治疗胸腰椎骨折的临床疗效。方法 2007年2月-2009年1月,对25例胸腰椎椎体骨折行椎弓根螺钉内固定、经伤椎一侧椎弓根进行椎体内植骨并行伤椎植钉治疗。其中男18例,女7例;年龄28～63岁,平均46岁。损伤椎体:T10 1例,T11 2例,T12 8例,L1 6例,L2 6例,L3 1例,L4 1例。骨折根据Denis分类:爆裂型骨折14例,屈曲压缩型骨折11例。按Frankel神经功能分级:A级2例,B级4例,C级8例,D级7例,E级4例。受伤至手术时间为6 h～7 d,平均4.6 d。手术前后摄X线片测量骨折椎体相对高度及Cobb角恢复情况,通过Frankel神经功能分级评价脊髓功能改善情况。结果患者均顺利完成手术,术后切口均Ⅰ期愈合。25例均获随访,随访时间12～25个月,平均16个月。术后1年CT及X线片示伤椎椎体内植骨融合良好,骨折均愈合,无螺钉松动、断钉、断棒现象。术前、术后即刻和术后1年骨折椎体相对高度分别为56.8%±15.6%、91.2%±10.7%和89.6%±10.3%,术后即刻及术后1年骨折椎体相对高度较术前恢复明显,差异均有统计学意义(P<0.01);术后1年与术后即刻比较差异无统计学意义(P>0.05)。术前、术后即刻和术后1年Cobb角分别为(18.2±2.6)、(7.5±1.4)、(8.7±1.1)°,术后即刻及术后1年与术前比较恢复明显,差异均有统计学意义(P<0.01);术后1年与术后即刻比较差异无统计学意义(P>0.05)。术后1年Frankel神经功能分级,16例有1～3级改善。结论经伤椎椎弓根椎体内植骨并植钉治疗胸腰椎骨折临床疗效满意,重建了椎体高度,增加了脊柱前中柱的稳定性,具有防止术后椎体高度丢失、减少内固定物松动、断裂等优点。     

青少年脊柱侧凸患者胸椎椎弓根螺钉置入的准确性和安全性评价

目的：探讨青少年脊柱侧凸患者胸椎椎弓根螺钉置入的准确性和安全性，以减少相关手术并发症。方法：32例青少年脊柱侧凸患者术前均对畸形脊柱进行标准俯卧位CT加密扫描，测量进钉点至椎体前缘的深度、进针角度、椎弓根直径和椎体的旋转角度，根据测得数据确定椎弓根螺钉置入的深度和方向，置入螺钉后再行脊柱全长X线片及CT扫描评价置钉的准确性和安全性。结果：32例共置入226枚胸椎椎弓根螺钉，术后CT加密和X线片观察到205枚螺钉（90．7％）完全在椎弓根皮质骨内。10例21枚螺钉（9.3％）发生错置，7枚螺钉（3．1％）偏外，5枚螺钉（2．2％）偏前外侧（其中2枚螺钉靠近节段血管），4枚螺钉（1．8％）偏下，4枚螺钉（1．8％）直径过大导致椎弓根内壁膨胀内移，1枚螺钉（0．4％）误入椎管导致完全性脊髓损伤。T1～T4错置12枚（18．2％），T5～T12错置9枚（6．1％）；凸侧椎根螺钉置入的准确率为93．8％，凹侧为83．1％。结论：脊柱畸形患者术前应常规采用标准俯卧位CT加密扫描，根据扫描图像测得的相关数据可为术中准确置入椎弓根螺钉提供重要参考依据。在青少年脊柱侧凸患者胸椎椎弓根螺钉置入有一定的误置率，螺钉发生错置多见于上胸椎和凹侧．术中应高度重视。     

计算机辅助颈椎椎弓根螺钉置入参数的获取

目的探讨利用CT三维重建技术模拟颈椎椎弓根螺钉置入的方法,以获得预置螺钉的椎弓根三维定量解剖数据及置钉参数。方法将颈椎16排CT扫描的数据导入Mimics8．1软件中,进行颈椎CT三维重建,在三维图像上构建一圆柱体来模拟椎弓根螺钉,并置入颈椎椎弓根内,然后测量各项置钉参数。结果应用CT三维重建技术可以获得清晰的颈椎三维图像,使用软件测量功能可精确地获取预置螺钉的椎弓根解剖数据（椎弓根宽度和轴线长度）和置钉参数（置钉的α角、β角以及置钉α角安全范围）。结论通过CT三维重建技术获取椎弓根螺钉置入个体化三维数据,为术中实施颈椎椎弓根螺钉置入提供依据,是颈椎椎弓根螺钉置入安全性研究的一种可靠方法。     

Computernavigierte Implantation transpedikulärer Schrauben in die Lendenwirbelsäule

OBJECTIVE: Decrease of surgical risks in transpedicular, lumbar spondylodesis by insertion of screws into the pedicle under continuous visual control of the screw channel in the sagittal, axial, and orthogonal planes in relation to the direction of screw insertion. INDICATIONS: All indications of a transpedicular lumbar spondylodesis performed for intervertebral instability, spinal stenosis, or displacement of vertebrae secondary to degenerative diseases. CONTRAINDICATIONS: Previous surgery that does not permit the obligatory intraoperative matching. Usual contraindications for lumbar spondylodesis. Spondylolyses, as they rarely allow a satisfactory result of matching due to the mobility in the vertebral segment. SURGICAL TECHNIQUE: Preoperative multi-slice computed tomography (CT). Intraoperative matching of real and virtual views. On the monitor the instruments are controlled visually in their relation to the lumbar spine in almost real time. Opening of pedicles and insertion of screws. Only thereafter, treatment of the pathologic conditions either by decompression or realignment of the spine. RESULTS: Between July 2000 and February 2002 this system was selected for 109 patients. No complications were observed and no revision became necessary. The screw length varied between 35 and 50 mm; the length of the screws does not affect the procedure. Intra- and postoperative radiographs (anteroposterior and lateral) were done in every patient. The first 48 patients underwent CT control that confirmed the optimal intrapedicular and intravertebral screw position. Thereafter, these controls were omitted for cost-saving.     

椎弓根钉道参数的变异性及其相关因素的研究

目的研究椎弓根钉道相关参数的变异性及引起变异的具有临床意义的相关因素。方法用PickerPQ6000螺旋CT扫描仪对C3～L5椎体进行扫描。共扫描198例(男118例,女80例)的736个椎体。测量每个椎体的椎弓根横径、钉道长度、及e角(椎弓根轴线与矢状面夹角),观察椎体形态及椎体、棘突、人体三者各自矢状轴间的关系,如有异常则测量并记录。同时记录受检者的性别、身高、体重。以上数据用SPSS软件进行统计学处理。结果统计结果显示:每一节椎体的椎弓根宽度、钉道长度及e角均有较大的极差及四分位数间距。虽然t检验显示不同性别间的钉道长度、椎弓根宽度均有明显的统计学差异,但在进一步以协方差分析法分析各因素的交互效应时发现,在消除体重、身高两因素后,椎弓根宽度及钉道长度均与性别无关。泊松相关分析显示身高、体重均与椎弓根宽度及钉道长度呈显著正相关,而e角与后两者无显著相关性。对椎体畸变的观察显示:14(1.9%)个胸腰椎椎体矢状轴与人体矢状轴不一致;11(1.0%)个椎体棘突轴与椎体矢状轴不一致;T9以下,14(4.9%)个椎体的椎弓根横径小于4mm;4个椎体椎弓根外凸变形,影响置钉位置。结论人体椎弓根钉道参数具有较大的变异性,不同个体、不同节段水平均有显著不同;体重和身高是两个影响变异性重要的相关因素。偶发     

经伤椎椎弓根内固定治疗胸腰椎爆裂性骨折简

目的观察经伤椎椎弓根内固定治疗胸腰椎爆裂骨折的临床效果。方法回顾性分析2009年1月至2011年12月在我院手术治疗的19例胸腰椎爆裂性骨折的临床资料,所有患者均采用经伤椎椎弓根内固定治疗,其中男性14例,女性5例,年龄23～58岁,平均（33．5±6．0）岁。骨折部位：T11 2例,L21例,T127例,L17例,T12-L1联合伤2例。术前、术后6个月及术后12个月均行X线及CT检查,分别测定伤椎前缘高度、矢状面Cobb角,进行疗效评估。结果患者手术均顺利完成,切口全部I期愈合,且均获得12个月随访。术后6个月及术后12个月伤椎前缘高度、矢状面Cobb角与术前相比,差异均有统计学意义（P〈0．05）,术后6个月与术后12个月相比差异无统计学意义（P〉0．05）。结论经伤椎椎弓根内固定治疗胸腰椎爆裂性骨折是临床上行之有效的方法。     

Computed tomographic evaluation of thoracic pedicle screw placement in idiopathic scoliosis

This retrospective observational study aimed to determine the accuracy of the placement of transpedicular thoracic screws used in idiopathic scoliosis and to evaluate the position and safety of the implants using postoperative computed tomography. Twenty-nine patients who underwent surgery for scoliosis between May 2003 and November 2005 were included in this study. The mean spinal curvature was 67°, and all of the patients had thoracic screws or hooks implanted. The positioning of 78 pedicle screws was evaluated using computed tomography after the free-handed technique was performed. The mean spinal curvature after surgery was 29°. Seventy-six percent of the screws were fully contained within the pedicle. Twenty-one screws breached the pedicle by between 2 and 4 mm (three medially and 18 laterally). Two screws were broken. A neurological deficit was identified in one case after surgery, but the deficit was reversed after the removal of the screws. This screw had a medial breach of greater than 4 mm. Most screws were inserted between the cortical vertebrae. Misplaced screws were most commonly inserted with a lateral cortical perforation.     

Morphometry of the cervical vertebral pedicles as a guide for transpedicular screw fixation

Anatomical measurements of the cervical pedicle in a large series of human cervical vertebrae from 48 individuals were obtained to reduce the incidence and severity of complications caused by transpedicular screw placement. The greatest pedicle length was at C-3 and the greatest pedicle width was at C-6. Pedicle width and lateral mass thickness gradually increased from C-3 to C-6. Pedicle height and interpedicular distance increased from C-3 to C-5, and decreased slightly at C-6. The lateral mass-pedicle length was greatest at C-4. The present study found right-left differences for the pedicle-spinous process distance at C-6 (p < 0.05). Pedicle width and height were smaller than those reported in earlier studies, especially at C-3 and C-4, whereas the increasing pedicle widths at C-5 and C-6 were appropriate for pedicle screw fixation.     

经一侧伤椎短节段椎弓根固定联合椎体内植骨治疗胸腰段椎体骨折

目的 探讨经一侧伤椎短节段椎弓根固定联合椎体内植骨治疗胸腰段椎体骨折的可行性及疗效.方法 将自2005年1月～2009年5月行短节段椎弓根钉固定联合椎体内植骨治疗的102例胸腰段椎体骨折随机分为两组.A组行后路短节段椎弓根钉固定结合经一侧伤椎椎弓根固定联合椎体内植骨,B组行后路跨伤椎短节段椎弓根钉固定联合椎体内植骨.结果 本组获随访12～24个月.术后1周后凸Cobb角、椎体前缘高度两组间比较,差异无统计学意义(P＞0.05),末次随访时A组矫正角度、椎体前缘高度丢失量明显小于B组,差异有统计学意义(P＜.05).B组末次随访时腰背痛发病率以及内固定失败率明显高于A组,差异有统计学意义(P＜0.05).结论 经一侧伤椎短节段椎弓根固定联合椎体内植骨治疗胸腰段椎体骨折是一种有效的方法.     

Incorporation of intraoperative computerized tomography in a newly developed spinal navigation technique.

OBJECTIVE: We report on the first successful incorporation of intraoperative computerized tomography in spinal navigation procedures. MATERIALS AND METHODS: All operations were performed with the aid of a Tomoscan M mobile CT system (Philips Medical Systems, Eindhoven, The Netherlands). The system comprises a mobile gantry, a mobile patient examination table, and a mobile workstation. Three different navigation systems were used: the EasyGuide (Philips Medical Systems, Eindhoven, The Netherlands), the Surgical Tool Navigator (Zeiss, Oberkochen, Germany), and a prototype of an ultrasound navigation system developed by ourselves (IVS GbR, Chemnitz, Germany). All surgical operations were performed with the patient positioned on the mobile table of the CT system. Following dorsal preparation of the vertebral region, the surgeon implanted small titanium screws in the vertebrae to serve as fiducial markers. Image data acquisition and image-to-patient registration were performed after implantation of the marker screws. The pedicle screws were inserted using the navigation system, and the position of each implant was confirmed by intraoperative CT scans. RESULTS: To date, 35 patients with various spine disorders have been operated upon using the technique described, and 161 pedicle screws have been inserted. There were no misplacements of pedicle screws. In three (1. 9 %) cases we observed lateral perforation (maximum 2 mm) of the lateral pedicle wall. We achieved a registration error of 0.85 mm (RMSE) +/- 0.42 mm (SD). CONCLUSIONS: The combination of intraoperative computerized tomography and spinal navigation allows easy navigation with a high application accuracy of 0.8 mm +/- 0.4 mm (SD) at the target point (measured in experiments with a plastic spine model). The possibility of performing an intraoperative quality check on demand markedly improves the safety of these procedures.     

Accuracy and safety of pedicle screw placement in neuromuscular scoliosis with free-hand technique

It is a retrospective analytic study of 1,009 transpedicular screws (689 thoracic and 320 lumbosacral), inserted with free-hand technique in neuromuscular scoliosis using postoperative CT scan. The aim of paper was to determine the accuracy and safety of transpedicular screw placement with free-hand technique in neuromuscular scoliosis and to compare the accuracy at different levels in such population. All studies regarding accuracy and safety of pedicle screw in scoliosis represent idiopathic scoliosis using various techniques such as free-hand, navigation, image intensifier, etc., for screw insertion. Anatomies of vertebrae and pedicle are distorted in scoliosis, hence accurate and safe placement of pedicle screw is prerequisite for surgery. Between 2004 and 2006, 37 consecutive patients, average age 20 years (9–44 years), of neuromuscular scoliosis were operated with posterior pedicle screw fixation using free-hand technique. Accuracy of pedicle screws was studied on postoperative CT scan. Placement up to 2 mm medial side and 4 mm lateral side was considered within-safe zone. Of the 1,009 screws, 273 screws were displaced medially, laterally or on the anterior side showing that 73% screws (68% in thoracic and 82.5% in lumbar spine) were accurately placed within pedicle. Considering the safe zone, 93.3% (942/1009, 92.4% in thoracic and 95.3% in lumbar spine) of the screws were within the safe zone. Comparing accuracy according to severity of curve, accuracy was 75% in group 1 (curve <90°) and 69% in group 2 (curve >90°) with a safety of 94.8 and 91.2%, respectively (P = 0.35). Comparing the accuracy at different thoracic levels, it showed 67, 64 and 72% accuracy in upper, middle and lower thoracic levels with safety of 96.6, 89.2 and 93.1%, respectively, exhibiting no statistical significant difference (P = 0.17). Pedicle screw placement in neuromuscular scoliosis with free-hand technique is accurate and safe as other conditions.