脊髓型颈椎病前后路手术的选择

目的：探讨脊髓型颈椎病前后路手术的适应证并评定其疗效。方法：自2002年6月至2006年6月采用前后路治疗125例脊髓型颈椎病患者,男71例,女54例;年龄28-69岁,平均53．4岁。病程0．5-48个月,平均14个月。58例行前入路,67例行后入路。通过JOA评分系统对手术前后神经功能分析,总结颈椎前后路手术疗效。结果：所有患者均获得随访,时间6-30个月,平均18个月。按JOA评分标准：颈前路手术组术前（8．78±2．43）分,术后（14．68±2．37）分,其中优40例,良10例,有效6例;颈后路手术组术前（8．49±2．58）分,术后（14．26±2．83）分,其中优42例,良12例,有效8例。6例手术无效,其中前路2例,后路4例,后路1例术后症状加重。两组间疗效无统计学差异（P〉0．05）,但同一入路术前术后比较有统计学差异（P〈0．05）。结论：前后路手术均能对脊髓型颈椎病的治疗起到良好的作用,来自前方的压迫,少节段病变,以锥体束受压症状为主者,原则上采取前路手术;而对于来自脊髓后方的压迫,多节段病变,以感觉障碍为主、伴有颈椎椎管狭窄者,则以颈后路手术为主。     

Radiographic criteria for placement of translaminar facet screws

Background contextScrew fixation of the facet joint has been reported to stabilize the lumbar spine and facilitate spinal fusion. Accurate placement of translaminar facet screws (TLFSs) requires identification of the posterior spinal elements, and the facet joints in particular, which may be facilitated by intra-operative fluoroscopy.PurposeThe purpose of this study was to define the radiographic parameters that will allow for successful placement of TLFSs.Study designEighteen TLFSs were placed in three human cadaver spines using fluoroscopic guidance, with screws placed from L3–L4 to L5–S1 bilaterally. After screw placement, the spines were dissected and examined for the accuracy of screw placement.MethodsIn the first cadaver spine, TLFSs were placed with direct visualization of the posterior lumbar spine, during which a fluoroscopic image intensifier was used to define the appropriate radiographic parameters for safe placement of the screws. Bilateral TLFSs were then placed percutaneously using the radiographic parameters developed, after which the spines were dissected to examine the positions of the screws.ResultsThe radiographic views identified to achieve proper TLFS placement were a true lateral, anteroposterior (AP), a 45-degree oblique and an AP view with the X-ray beam at a 30- to 45-degree cephalad angle (“spinal outlet” view). Using these views and the defined radiographic criteria, proper positioning of percutaneously placed TLFSs was achieved, with no spinal canal breaches found.ConclusionsThis study defines intra-operative radiographic criteria that will assist in placement of TLFSs. The use of this technique may allow for screw placement with less extensive exposure of the posterior spine.     

Routine evaluation of the cervical spine in head-injured patients with dynamic fluoroscopy: a reappraisal.

BACKGROUND: The mechanism for clearing the cervical spine in patients with altered mental status remains controversial. Recommendations have ranged from removal of the cervical collar after 24 hours in patients with normal radiographs, to indefinite immobilization in a cervical collar, and recently cervical flexion-extension examinations using dynamic fluoroscopy. The purpose of this study was to evaluate the efficacy and safety of dynamic fluoroscopy flexion-extension examinations in identifying ligamentous cervical spine injury and clearing the cervical spine in patients with altered mental status after trauma. METHODS: Patients with a Glasgow Coma Scale score < 13 for greater than 48 hours after admission and normal cervical spine radiographs were candidates for fluoroscopic evaluation. The protocol required visualization of the entire cervical spine, through T1, through full extension and flexion under the direct supervision of a radiologist. Oblique fluoroscopic views were obtained, as necessary, to visualize the cervicothoracic junction. Demographic data, fluoroscopy time, total time per study, true and false positives and negatives, and complications were recorded. RESULTS: From July 1992 through December 1999, fluoroscopic examinations were performed on 301 patients. There were 297 true-negative examinations, 2 true-positive examinations (stable injuries), 1 false-negative examination, and 1 false-positive examination. The incidence of ligamentous injury identified by fluoroscopy in this study was 2 of 301 (0.7%). Unstable cervical spine ligamentous injuries were identified in only 0.02% of all trauma patients. One patient developed quadriplegia when fluoroscopic evaluation was performed after two protocol violations. CONCLUSION: Unstable cervical spine ligamentous injury without fracture is a rare occurrence. The cervical spine may be cleared after a normal cervical spine series (plain radiograph and computed tomographic scan) as recommended in the 1998 Eastern Association for the Surgery of Trauma guidelines. If dynamic fluoroscopy is to be used, adherence to the protocol, including review of the cervical spine radiographs before fluoroscopy and visualization of the entire cervical spine, C1-T1, is mandatory to ensure patient safety.     

Nontraumatic posterior atlantooccipital dislocation associated with atlantoaxial instability

Introduction

Nontraumatic posterior atlantooccipital dislocation has only been rarely reported. In the current study, the authors reported an extremely rare case of nontraumatic posterior atlantooccipital dislocation associated with atlantoaxial instability.

Materials and methods

A 47-year-old female was referred with a history of neck pain for 5 years. The patient had no history of trauma. The axial rotation of range of motion of the cervical spine was severely restricted. Posterior atlantooccipital dislocation with atlantoaxial instability was confirmed through conventional radiography, computed tomography and magnetic resonance imaging. We performed realignment of the dislocation and posterior occipitocervical (C0–C2) fusion. After the surgery, the patient’s symptoms improved significantly and she manifested neurological improvement.

Conclusion

To our knowledge, this lesion has not been reported previously. Anomalies of upper cervical spine may have induced this instability.

     

Ossification of the posterior cervical longitudinal ligament

Summary Forty patients with cervical myelopathy due to OPLL (Ossification of the Posterior Longitudinal Ligament) of the cervical spine were studied. According to Abe's or Yamamoto's classification, 12 of them had a 50% decrease in the cross-sectional area of the spinal canal. Subtotal vertebrectomy was carried out in 8 of these patients and the remaining 4 patients received posterior decompression. We concluded that anterior decompression, if possible, is the treatment of choice and posterior decompression is recommended only for the longitudinal type involving more than 3 segments.     

Retrospective study of posterior cervical fusions with rhBMP-2

Posterior cervical decompression and fusion can be performed for various spinal conditions. Previous rates of pseudoarthrosis have been reported in up to 38% of patients. The use of bone morphogenic protein (BMP) has been approved for use in certain anterior lumbar interbody fusion techniques to decrease the incidence of pseudoarthrosis. Bone morphogenic protein in the anterior cervical spine carries a potential increased risk of airway complications; however, few data exist on the safety and efficacy of BMP in the posterior cervical spine. The purpose of this study was to evaluate fusion success, safety, and heterotopic bone formation using BMP in posterior cervical fusion.Twenty-nine patients who received posterior cervical fusion with BMP were followed for a minimum of 12 months. Computed tomography scans were obtained at a minimum of 12 months postoperatively to evaluate for solid arthrodesis and the presence of heterotopic bone formation. Patients' demographic data and adverse events were evaluated. All patients underwent posterior cervical decompression and instrumented fusion of at least 1 level between 2006 and 2008. Of 37 patients eligible for the study, 29 agreed to participate. Three (10.3%) of 29 patients developed pseudoarthrosis, as found on computed tomography scan. None of these went on to further surgery. No evidence existed of heterotopic bone formation outside of the lateral masses or bone growth over the spinal canal or neuroforamen. No adverse events were related to the use of BMP in this series of posterior cervical fusions. Bone morphogenic protein can be used safely in posterior cervical spine fusion, but additional larger studies are recommended. Even with the use of bone morphogenic protein, the possibility of pseudoarthrosis exists.     

颈前路椎间盘切除椎间融合器融合术加颈后路单开门术治疗脊髓型颈椎病

[目的]探讨颈椎前路椎间盘切除椎间融合器融合术加颈椎后路单开门椎管扩大成形术治疗脊髓型颈椎病在临床上的应用价值。[方法]应用Cervical Cage行颈椎前路椎间盘切除椎间融合术，同时，颈椎后路行单开门椎管扩大成形术11例，平均随访6个月。按40分法和JOA评分对手术前后脊髓功能进行评分，并测量颈椎术前术后前柱高度及椎管宽度和进行相关性分析．[结果]颈椎前路椎间盘切除椎间融合器融合术加颈椎后路单开门椎管扩大成形术，明显改善脊髓型颈椎病的脊髓功能。40分法平均37分，改善率83％；JOA评分16．5分，改善率91％；前柱高度平均增加1．28mm；椎管宽度平均增加2．22mm。[结论]颈椎前路椎间盘切除椎间融合器融合术加颈椎后路单开门椎管扩大成形术，有效恢复了颈椎前柱高度、增加椎管宽度，明显改善了脊髓型颈椎病的脊髓功能。     

椎板后壁部分刮除辅助透视行颈椎弓根钻孔

目的探索椎板后壁部分刮除辅助透视行下颈椎椎弓根钻孔的可行性。方法3具新鲜尸体下颈椎的30例椎弓根，透视确定椎弓根轴线所在高度，将此高度侧块与椎板后壁交界内外侧各5mm范围内的皮质骨去除，刮除其下松质骨，先暴露出内侧的椎板前壁，后紧贴椎板前壁向外侧刮除，找到椎弓根入口。根据内倾角确定入口外侧骨质去除范围，以椎弓根内壁为参照，透视确定上倾角，行髓腔钻孔。CT扫描明确钻孔准确性。结果1例髓腔消失，放弃钻孔；27例钻孔准确；2例髓腔〈3mm，椎弓根外壁向外侧移位，但〈2mm。结论椎板后壁部分刮除辅助透视行下颈椎椎弓根髓腔钻孔效果满意。     

Limitations of minimally invasive posterior cervical foraminotomy—a decompression method of posteriorly shifting the nerve root—in cases of large anterior osteophytes in cervical radiculopathy: A retrospective multicenter cohort study

BackgroundPosterior cervical foraminotomy against anterior osteophyte is an indirect decompression procedure but less invasive compared to anterior cervical discectomy and fusion. Residual compression to the nerve root may lead to poor surgical outcomes. Although clinical results of posterior cervical foraminotomy for osteophytes are not considered better than those of disk herniation, osteophyte size and the association of the decompression area with poor surgical outcomes remain unclear. This study aimed to identify the limitations of minimally invasive posterior cervical foraminotomy for cervical radiculopathy and discuss the methods to improve surgical outcomes.MethodsWe analyzed 55 consecutive patients with degenerative cervical radiculopathy who underwent minimally invasive posterior cervical foraminotomy. Minimum postoperative follow-up duration was 1 year. We divided the patients into nonimproved and improved groups. The cutoff value between preoperative and postoperative Neck Disability Index scores was 30% improvement. Preoperative imaging data comprised disk height, local kyphosis, spinal cord compression, anterior osteophytes in the foramen, and anterior osteophytes of >50% of the intervertebral foramen diameter. Postoperative imaging data comprised craniocaudal length and lateral width of decompressed lamina, preserved superior facet width, and area of decompressed lamina.ResultsFifty-five patients were divided into two groups: nonimproved (n = 19) and improved (n = 36). The presence of osteophytes itself was not significant; however, the presence of osteophytes of >50% of the foramen diameter increased in the nonimproved group (P = 0.004). Mean lateral width and mean area of decompressed lamina after surgery significantly increased in the improved group (P = 0.001, P = 0.03).ConclusionThe presence of anterior osteophytes >50% of the diameter of the foramen led to poor improvement of clinical outcomes in minimally invasive posterior cervical foraminotomy. However, the larger the lateral width and area of the decompressed lamina, the better the surgical outcome.     

Arthroscopic Anterior Diskectomy of the Cervical Spine

We describe a minimally invasive arthroscopic technique for anterior diskectomy of the cervical spine. Fingertip pressure is applied between the carotid sheath laterally and the pharynx medially. The trachea and esophagus are displaced to the contralateral side. The disk level, soft-tissue thickness, and midline are verified with image intensification. A spinal needle is inserted through the soft tissue into the disk space at the midline. Contrast is injected to facilitate visualization. While maintaining displacement of the pharynx, a 4-mm vertical incision is made to incorporate the needle and is enlarged bluntly. A guidewire is passed through the needle. A dilator is passed over the guidewire, through the soft tissue, and usually into the disk, stopping posterior to the mid-vertebral body, as verified with lateral imaging. A cannula is placed over the dilator, and the dilator and wire are removed. Occasionally, the cannula is passed over the dilator to the anterior aspect of the disk, and the dilator is replaced with a trephine to penetrate the anterior spinal ligament, osteophytes, and annulus. The cannula seated in the middle of the disk allows diskectomy to commence with small rongeurs through the cannula, followed by a cervical spine arthroscope with a working channel. The arthroscope is removed, and further diskectomy is performed under fluoroscopic guidance with a motorized shaver and radiofrequency probe.     

Posterior arch defects of the cervical spine: a comparison between absent pedicle syndrome and spondylolysis

Background contextAbnormalities of the posterior arch are rare entities that are usually found incidentally on neck radiographs. Their radiographic appearance may cause them to be confused with more serious entities such as fractures, locked facets, and tumor-induced bony erosions. It is important to distinguish these posterior arch abnormalities from the other entities because the treatment is very different.PurposePosterior arch defects of the cervical spine, including cervical spondylolysis and absent pedicle syndrome, occur rarely. In this case report, we describe three cases of posterior arch defects and present a review of the literature concerning the distinguishing features between spondylolysis and absent pedicle syndrome.Study designA case report and literature review of the posterior arch defects.MethodsTwo patients are presented who developed posterior neck pain after trauma. They had no neurologic deficits, but cervical radiographs suggested that they had a traumatic injury. Cervical spine computed tomography (CT) revealed absent pedicle syndrome and they were treated conservatively. Another patient is presented who developed worsening posterior neck pain and left shoulder pain. She had no history of significant neck injury. Cervical radiographs and CT showed bilateral spondylolysis of C6 vertebra and subluxation of C6 on C7. Because her symptoms were not relieved by conservative measures, we performed anterior cervical discectomy and fusion.ResultsWe treated two patients with absent pedicle syndrome by conservative measures and one patient with cervical spondylolyis by surgical treatment.ConclusionsPosterior arch defects were often confused with other disease entities. But, they have some distinctive features and such distinctive features may be helpful in confirming diagnosis and planning treatment. Furthermore, three-dimensional CT scan reconstruction provides comprehensive anatomic evaluation of the structures with an absent pedicle and the associated bony abnormalities.     

经皮间接减压内固定术治疗伴有神经损伤的胸腰椎爆裂性骨折

目的探讨后路经皮间接减压内固定术治疗伴有神经损伤的胸腰椎爆裂性骨折的有效性及安全性。方法 2015年6月—2017年6月,共25例伴神经损伤的胸腰椎爆裂性骨折患者接受后路经皮间接减压内固定术治疗。采用Frankel分级评估神经功能等级,采用疼痛视觉模拟量表(VAS)评分评估腰背部疼痛程度。测量并记录术前、术后及末次随访时矢状位Cobb角、伤椎椎体前缘高度百分比、伤椎楔形角、椎管占位率等影像学指标。结果所有患者手术均顺利完成,随访6～24(12.6±5.6)个月,末次随访时所有患者腰背部疼痛症状均明显改善,椎管得到有效减压,神经功能均明显改善,椎体骨折复位愈合,随访无明显丢失,无内固定相关并发症发生。结论后路经皮间接减压内固定术可避免椎管内直接减压,保护脊柱后方结构,减少手术创伤,临床疗效满意,对于伴有不完全神经损伤的胸腰椎爆裂性骨折的治疗是一种微创、安全、有效的选择。     

C3–C4 spondyloptosis without neurological deficit—a case report

Background contextTraumatic spondyloptosis of the cervical spine is usually associated with a complete, or rarely a partial, neurological deficit. Traumatic spondyloptosis with bipedicular fracture of the C3 vertebra is uncommon. To the best of the authors' knowledge, there is no report in the literature of bipedicular fracture of C3 with spondyloptosis of C3 over C4 with no neurological deficit. Literature is not clear about the role of preoperative traction in neurologically intact patients, and most authors advise both anterior and posterior fixation for cervical spondyloptosis.PurposeTo report a case of C3–C4 spondyloptosis with C1 and C2 posterior arch fractures with no neurological deficit and its management strategy and underline the fact that closed reduction and limited anterior fusion can preserve the motion segment of cervical spine at other fractured levels and give a stable cervical column with good long-term results.Study designA case report with review of the literature.MethodsA 35-year-old man fell from a height with hyperextension-compression injury to the cervical spine. The patient suffered fracture of the posterior elements of C1–C3 along with spondyloptosis of C3 over C4 without any neurological deficit. The patient was treated with an awake nasotracheal intubation with gradual cervical traction under fluoroscopic guidance to acceptable alignment followed by anterior cervical fusion at C3–C4.ResultsAt 24 months' follow-up, the C3–C4 level fused completely with fracture healing at C1 and C2. The patient remained asymptomatic with normal neurological examination and near complete cervical motion. The patient returned to his preinjury job and recreational activities.ConclusionsA case of C3–C4 spondyloptosis with associated C1–C2 posterior arch fracture is reported. The patient can present without neurological deficit if associated with a fracture of the posterior elements. Spondyloptosis without neurological deficit can be treated with gradual reduction under fluoroscopic guidance. A limited anterior-only fusion at the spondyloptosis level can provide good long-term results with preservation of other motion segments.     

Anatomic and radiographic considerations for placement of transiliac screws in lumbopelvic fixations

Lumbopelvic fixation in spinal and pelvic surgery relies on rods or screws as an iliac anchor. Secure placement of screws with maximum diameter and length for the greatest pullout strength requires knowledge of the iliac structure and of intraoperative fluoroscopic landmarks for secure placement. Therefore, the authors evaluated the intrailiac length, inner width, and cortical thickness of three different transiliac screw anchor paths aimed toward the anterior inferior iliac spine and initiated at the iliac tubercle, posterior superior iliac spine, or posterior inferior iliac spine. Measurements were made using two- and three-dimensional computed tomographic reformations in 40 consecutive trauma patients (27 measurements in 21 males, 16 to 75 years old; 28 measurements in 19 females, 16 to 78 years old). In addition, fresh and dry human cadaveric specimens were marked with metal wires at the previously determined optimal screw path to determine fluoroscopic landmarks for easiest and best controlled transiliac screw placement. The posterior superior iliac spine-anterior inferior iliac spine path had the largest bony canal lengths, with 141 mm in male and 129 mm in female patients. Two stereotypic iliac constrictions allowed placement of 8-mm implants in male and 6- to 7-mm implants in female patients. Cortical thickness at that optimal extraarticular path was 5.2 mm in the male and 4.7 mm in the female patients. Transiliac screws can be placed during operation under fluoroscopic control using standard lateral and obturator oblique-outlet views, the latter presenting a stereotypical teardrop figure above the acetabulum.     

Fluoroscopic imaging guides of the posterior pelvis pertaining to iliosacral screw placement

BACKGROUND: This study correlates anatomic landmarks with radiographic densities and radiolucencies of the posterior pelvis, which assists in percutaneous iliosacral screw placement. METHODS: Radio-opaque markers were placed on selected surfaces of cadaveric specimens and rotated under a fluoroscopic beam. Identified surfaces were described with angular measurements and anatomic characteristics. RESULTS: The anterior border of the S1 body is not parallel to the anterior border of the S1 ala. The anterior surface of the S1 ala is found on the inlet view ( approximately 49 degrees ) by the superimposition of the S1 and S2 alar ridges. Superior surface of the S1 ala is difficult to visualize fluoroscopically because of the highly oblique outlet angle required by fluoroscopy ( approximately 80 degrees ). The superior ridge of the S1 foramen can best be seen during an outlet view when the projection of the superior pubic symphysis is superimposed on the S2 foraminal image. Posterior bony surfaces of the ilium, foraminal region of sacrum, and sacral body are difficult to identify, as are the bony surfaces of the sacral foramina. During screw placement, the narrowest area of bone occurs in the sacral foraminal region. CONCLUSIONS: Use of predetermined angles for inlet and outlet views may not provide optimal visualization of relevant bony landmarks during iliosacral screw insertion. Because of variable sacral morphologies and lumbosacral lordosis, we propose using inherent landmarks to help visualize important landmarks during screw placement. Altering the fluoroscopic angle to superimpose the anterior S1 and S2 alar opacities allows the best visualization of the anterior boundary of the S1 ala. The superior bony surface of the S1 foramen is best visualized on the outlet view.     

Surgically treated cervical myelopathy: a functional outcome comparison study between multilevel anterior cervical decompression fusion with instrumentation and posterior laminoplasty

Background contextMultilevel cervical myelopathy can be treated with anterior cervical discectomy and fusion (ACDF) or corpectomy via the anterior approach and laminoplasty via the posterior approach. Till date, there is no proven superior approach.PurposeTo elucidate any potential advantage of one approach over the other with regard to clinical midterm outcomes in this study.Study designA prospective, 2-year follow-up of patients with cervical myelopathy treated with multilevel anterior cervical decompression fusion and plating and posterior laminoplasty.Patient sampleIn total, 116 patients were studied. Sixty-four patients underwent ACDF two levels and above or anterior cervical corpectomy and fusion one level and above. Fifty-two patients underwent posterior cervical surgery (laminoplasty C3–C6 and C3–C7).Outcome measuresSelf-report measures: Japan Orthopedic Association (JOA) score, JOA recovery rate, visual analog scale for neck pain (VASNP), neck disability index (NDI), and American Academy of Orthopaedic Surgeons (AAOS) neurogenic symptom score (AAOS-NSS). Physiologic measures: range of motion (ROM) flexion and extension of neck. Functional measures: short-form 36 (SF-36) score comprising physical functioning, physical role function, bodily pain, general health, vitality, social role function, emotional role function, and mental health scales.MethodsComparison of the JOA scores, JOA recovery rates, NDI scores, SF-36 scores, VASNP, and ROM preoperatively to 2 years. Chi-square and two-sided Student t tests were used to analyze the variables.ResultsPosterior surgery took an hour shorter (p<.05) and had better improvement in JOA scores at early follow-up of 6 months (p=.025). Anterior surgery group had better improvement of NDI scores at early follow-up of 6 months (p=.024) and was associated with less blood loss intraoperatively compared with posterior surgery. There was no statistical difference between the two groups for JOA scores, JOA recovery rates, SF-36 quality-of-life scores, NDI, AAOS-NSS, VAS neck pain, and ROM at 2 years. Complications were higher for anterior surgery group: two hematoma postoperation, one vocal cord paresis, and one new onset C6/C7 dermatome numbness versus one dura leak in posterior surgery group.ConclusionsOur study showed that patients with multilevel disease treated with laminoplasty do well and compare favorably with patients treated with an anterior approach. Notably, posterior surgery was associated with shorter operating time, better improvement in JOA scores at 6 months, and a tendency toward lesser complications. Posterior surgery was not associated with increased neck disability and neck pain at 2 years. Anterior surgery had better NDI improvement at early follow-up. There is a need for a larger study that is prospectively randomized with long-term follow-up before we can confidently advocate one approach over the other in the management of cervical myelopathy.     

Minimally invasive lateral mass plating in the treatment of posterior cervical trauma: surgical technique

OBJECTIVE: The technique of lateral mass fixation restores the posterior tension band and provides effective stabilization in patients with many types of traumatic injuries. However, postoperative wound pain is not uncommon. The objective of this work is to describe a modified technique of minimally invasive lateral mass plating for cervical spine trauma. METHODS: Patient 1 was a 64-year-old woman who had been in a motor vehicle accident and sustained bilateral C5-C6 facet dislocation with posterior C5-C6 distraction. She was otherwise neurologically intact, and attempts at closed reduction were not successful. Patient 2 was a 16-year-old girl who had also been in a motor vehicle accident but had an incomplete spinal cord injury. She had an unstable burst fracture of C7 with posterior C5-C6 distraction. Both patients underwent anterior cervical fusion followed by staged minimally invasive posterior fusion with good results. A dilator tubular retractor system (METRX) was used to access the bilateral lateral masses through a small midline incision under fluoroscopic guidance. Lateral mass screws were then placed by using a modified Magerl technique, securing two-hole plates on each side onto the lateral masses, performed through the METRX system. We also successfully performed four-level lateral mass plating in a cadaveric cervical spine using a 2-cm skin incision. CONCLUSIONS: We describe successful placement of lateral mass screw and plate constructs with the use of a minimally invasive approach by means of a tubular dilator retractor system. This approach preserves the integrity of the muscles and ligaments that maintain the posterior tension band of the cervical spine.     

下颈椎关节突关节与椎体后缘关系的影像学研究

目的：研究探讨下颈椎关节突关节前缘与椎体后缘的位置关系，为临床行下颈椎经关节螺钉植入时评价进钉深度提供参考。方法：选取无明显下颈椎畸形的标准颈椎侧位X线片100张，下颈椎标准CT平扫片50张，测量下颈椎关节突关节顶点、中部、基底部前缘与椎体后缘的距离（分别记为HS，HM，HI），椎体后缘之前为负、之后为正。并对测量数据行统计学分析。结果：所有关节突关节前缘距离、椎体后缘的距离从顶点到基底部逐渐减小（HS〉HM〉HI）。C。关节突关节前缘大多位于椎体后缘之前（HS，HM，HI均为负值）；C4.5C5.6关节突关节前缘逐渐后移；Co，，关节突关节前缘均位于椎体后缘之后（HS，HM，HI均为正值）。下颈椎关节突关节顶点前缘与椎体后缘的距离HS从C。到C6，7逐渐增大，C3．4为（0±0．25）mm，C4．5为（2．03±0．47）mm，C5．6为（2．45±0．56）mm，C6．7为（2．91±1．05）mm；下颈椎关节突关节中部前缘与椎体后缘的距离HM从C3.4到C6.7逐渐增大，C3.4为（-1．57±0.53）mm,C4.5为（O．50±0．26）mm，C5．6为（0．56±0．36）mm，C6．7为（1．54±0．39）mm；下颈椎关节突关节基底部前缘与椎体后缘的距离HI从C3.4到C6.7逐渐增大，C3.4为（-2．03±0．40）mm，C4．5为（0±0．30）mm，C5，6为（0．50±0．44）mm，C6．7为（1．08±0．70）mm。结论：在行下颈椎经关节螺钉固定时，螺钉的头部在C3.4应位于相应榷体后缘前方0～2mm，C4.5应位于相应椎体后缘之后0-2mm，C5.6应位于相应椎体后缘之后0．5-2．5him，C6.7应位于相应椎体后缘之后1～3mm。下颈椎关节突关节前缘与椎体后缘关系的确立，可为临床工作中下颈椎经关节螺钉植入时判断进钉深度提供参考。     

Abstracts Presented at Aps Forty-Fifth Annual Conference Paper Abstracts

Abstract

Background: Image guidance provides additional anatomic information to the surgeon, which may allowmore accurate insertion of spinal implants. Imprecise placement of anterior thoracic screws places the spinalcord and paraspinal structures at risk for injury. Image guidance may afford a safety benefit to patients whenanterior thoracic screws are required in the setting of spinal stabilization after trauma.

Objectives: To compare the accuracy of anterior thoracic screw placement using standard fluoroscopy,computer-assisted fluoroscopic image guidance, lso-C3D image guidance, and electromagnetic fluoroscopicimage guidance.

Study Design: A surgical simulation study in human cadaver spine specimens.

Methods: After an open thoracotomy approach, anterior thoracic screws were placed by experienced spinesurgeons using 4 different image-guided techniques in 4 human cadaver thoracic spines. Screws were placedin the 9th, 1Oth, and 11th thoracic vertebrae of each specimen. The specimens were then examined with thincutcomputed tomography (CT) scans, and with sagittal and coronal reconstructions. Measurements includedthe distance of the screw from the spinal canal, the angle of the screw path in relation to a perpendicular toa line that bisects the spinous process, and the angle of screw divergence from the superior endplate.

Results: There was no evidence of sp inal canal penetrance with any of the image-guided techniques usedto place anterior thoracic vertebral body screws. Screws inserted with standard fluoroscopy tended to aimanterolaterally by 18°. The image-guidance systems allowed more accurateplacement of anterior thoracicscrews in the transverse plane compared with standard fluoroscopy. There was no statistically significantdifference in coronal plane screw angulation (angle of divergence with the superior endplate) between anyof the imaging methods.

Conclusions: Spinal image-guidance systems may allow spine surgeons to place anteriorthoracic screws moreprecisely, particularly in the axial plane. The improved accuracy of spinal implant insertion could ultimately provide a benefit to patient safety, especially in the setting of malaligned vertebral bodies after trauma.