Assessing the Stiffness of Spinal Fusion in Animal Models

The clinical goal of spinal fusion is to reduce motion and the associated pain. Therefore, measuring motion under loading is critical. The purpose of this study was to validate four-point bending as a means to mechanically evaluate simulated fusions in dog and rabbit spines. We hypothesized that this method would be more sensitive than manual palpation and would be able to distinguish unilateral vs bilateral fusion. Spines from four mixed breed dogs and four New Zealand white rabbits were used to simulate posterolateral fusion with polymethyl methacrylate as the fusion mass. We performed manual palpation and nondestructive mechanical testing in four-point bending in four planes of motion: flexion, extension, and right and left bending. This testing protocol was used for each specimen in three fusion modes: intact, unilateral, and bilateral fusion. Under manual palpation, all intact spines were rated as not fused, and all unilateral and bilateral simulated fusions were rated as fused. In four-point bending, dog spines were significantly stiffer after unilateral fusion compared with intact in all directions. Additionally, rabbit spines were stiffer in flexion and left bending after unilateral fusion. All specimens exhibited significant differences between intact and bilateral fusion except the rabbit in extension. For unilateral vs bilateral fusion, significant differences were present for right bending in the dog model and for flexion in the rabbit. Unilateral fusion can provide enough stability to constitute a fused grade by manual palpation but may not provide structural stiffness comparable to bilateral fusion.     

腰椎手术失败综合征的再手术治疗

[目的]探讨腰椎手术失败综合征（FBSS）再手术治疗的方式和注意事项。[方法]对20例再手术治疗的腰椎手术失败综合征（FBSS）患者进行回顾性研究，综合分析FBSS患者的病史、体征、影像学表现以及术中探查结果等资料。术中行硬膜囊和神经根减压以及自体骨植骨融合，其中12例腰椎失稳的患者辅以椎弓根钉系统固定，术后进行一定的康复锻炼。[结果]术中损伤神经根1例，术后暂时性的脑脊液漏3例。治疗效果参照Ragab的评估标准进行综合评估。本组20例患者，治疗效果优12例，良5例，可2例，差1例；优良率为85％。[结论]FBSS是一多病因多表现的综合征，术前应当综合分析患者的临床表现，寻求病因，制订适宜的手术方案。     

保留后方韧带复合体在胸腰椎骨折治疗中的意义

[目的]探讨保留后方韧带复合体在胸腰椎骨折治疗中的意义。[方法]1998～2002年单一节段胸腰椎爆裂骨折治疗中保留后方韧带复合体44例，同期行胸腰椎爆裂骨折治疗切除后方韧带复合体者35例。两种方法分别有15例（定义为A组）和12例（定义为B组）行2次手术取出内固定物，比较AB两组间2次手术前后腰椎功能JOA评分。[结果]2次手术前腰椎功能JOA评分：A组平均24．5分（19～29分）；B组平均22．8分（19～29分），二者无显著性差异（P〉0．05）。2次手术后JOA评分：A组平均24．8分（20～29分），B组平均17．5分（13～26分）。二组有显著性差异（P〈0．05）。[结论]胸腰椎骨折治疗中保留后方韧带复合体，利于术后腰椎功能恢复。     

过伸性颈椎颈髓损伤的手术入路疗效比较

目的探讨过伸性颈椎颈髓损伤后三种手术入路疗效的比较。方法我们对2000年9月～2004年10月间收治的47例过伸性颈椎颈髓损伤并接受手术治疗的患者进行回顾性分析，根据手术方式不同分成三组：前路入路组、后路入路组、前后联合入路组，比较其疗效。结果所有患者经6～12个月随访，比较三组间手术前、后的Frankel的分级变化和ASIA评分改变。三组术后神经功能均较术前有明显改善；前路减压、植骨内固定和前后联合入路减压、植骨内固定均较后路减压、植骨内固定术后神经功能恢复好，两两间差异有显著性意义（P〈0．05）；前后联合入路减压最彻底，但其预后与单纯前路减压内固定差异无显著性意义（P〉0.05）。结论前路减压内固定是过伸性颈椎颈髓损伤首选的手术方式，后路是辅助的手术方法，而前后联合入路应谨慎选用。     

特发性颈椎后凸畸形的手术治疗

目的 :明确颈椎前路手术治疗特发性颈椎后凸畸形的可行性和局限性。方法 :本文对 14例颈椎特发性后凸畸形患者采取手术方法进行治疗 ,所有患者均采用颈椎前路椎间盘切除减压 ,椎间隙植骨和前路钢板内固定。结果 :手术后患者临床体征明显改善 ,颈椎后凸畸形由手术前平均 -15 6°矫正为手术后平均 -6 4° ,矫正效果明显 ;手术后患者的短期随访表明颈椎矫正度数在随访中没有丢失。结论 :前路手术 ,延长颈椎前柱能够矫正颈椎的后凸畸形 ,改善临床症状和体征     

Upper thoracic myelopathy caused by vertebral collapse and subluxation in rheumatoid arthritis: report of two cases

We report two cases of rheumatoid arthritis (RA) with upper thoracic myelopathy and a review of the literature. Clinical data of a 47-year-old woman (case 1) and a 54-year-old woman (case 2) are described. Case 1 showed a transverse-type myelopathy at the T2 segment level of the spinal cord and case 2 had the same type of myelopathy at the T4 segment level. Case 1 had anterior vertebral subluxation of C7 due to marked vertebral collapse and Case 2 had subluxation of T2 with vertebral destruction. These two patients had the mutilating type of RA with multilevel spontaneous fusion in the cervical spine. The lesions in the thoracic spine might be caused by the severe destructive inflammation that is characteristic in mutilating disease. The vertebral collapse might lead to subluxation of the upper thoracic vertebra, resulting in spinal cord compression. Upper thoracic subluxation might be caused by vertebral collapse due to RA and the increased motion as a compensation for decreased mobility caused by spontaneous fusion in the cervical spine.     

AF系统治疗胸腰椎骨折脱位的相关问题

目的 :探讨AF系统治疗胸腰椎骨折脱位的相关问题与效果。方法 :应用AF系统经椎弓根内固定治疗胸腰椎骨折脱位 3 6例 ,合并脊髓损伤 3 2例 ,同时行椎板减压 2 8例 ,植骨 6例。结果 :3 3例椎体高度完全恢复 ,神经功能按ASIA标准 2 5例有 1～ 3级恢复。结论 :AF系统治疗胸腰椎骨折脱位 ,椎体复位好 ,固定安全可靠 ,术中正确掌握椎弓根螺钉植入、椎管减压和复位技巧等环节 ,可进一步提高疗效。     

Anterior thoracic corpectomy without sternotomy: A strategy for malignant disease of the upper thoracic spine

SummaryBackground With increasing frequency, spine surgeons are being asked to provide decompression and stabilization in patients with spinal metastases. While no region of the spine is easily treated, the upper thoracic spine is perhaps the least accessible. Traditional approaches to this region involve either thoracotomy or at least limited sternotomy. The authors present an approach to anterior pathology of the upper thoracic spine that obviates the need for sternotomy.Methods Within the past two years, two patients with cervicothoracic metastases underwent anterior decompression and fusion without sternotomy. In both patients, the bodies of C7, T1, and T2 were removed. While both patients were prepared and draped for sternotomy, each required a neck dissection only. In both patients, left-sided incisions were made along the leading edge of the sternocleidomastoid. The platysma was divided with the overlying skin. With further dissection, the strap muscles were tagged and divided approximately one centimeter above their sternal attachments. The loose areolar tissue of the superior mediastinum was then bluntly dissected. Along the entire length of the incision, the vascular plane medial to the carotid sheath was developed to facilitate exposure of the anterior spine. A Farley-Thompson retractor system was then employed to retract and protect the superior mediastinal structures. With this exposure, corpectomies were carried out using a high speed drill. Fusion was accomplished through insertion of Steinmann pins into the adjacent intact bodies above and below. This was followed by application of methyl methacrylate. Both patients had immediate postoperative stability with preservation of spinal cord function. Both patients subsequently underwent removal of dorsally located tumor with posterior fusion.Conclusions The goal of cancer surgery is to provide for increased functional survival without undue morbidity. The authors feel that when possible, the pain of sternal and clavicular osteotomies should be avoided. The described approach works well in conjunction with a methyl methacrylate/Steinmann pin construct. Because of the intact sternum, the surgeon has a downward angle to access the superior endplate of T3. With adequate soft tissue dissection and retraction as described, however, T3 and perhaps even T4 are easily accessible. While this downward angle would likely not permit an anterior plating procedure, it lends itself nicely to Steinmann pin/methyl methacrylate fusion and spares the patient the pain and potential morbidity of sternotomy.     

腰椎椎弓崩裂CT征象的临床诊断价值

目的分析腰椎椎弓峡部裂的CT表现,探讨各个征象的诊断价值和意义.方法自可疑椎弓峡部裂脊椎的椎弓根的上缘至下一个椎弓根上缘,层厚2～3mm连续扫描.结果86例中发生L5椎弓峡部裂51例,L4者33例,L3,者2例.各种CT征象发现率为:环裂征91%,椎体前移征85%,双椎体征50%,椎管拉长征45%,双关节面征38%,葫芦征26%,游移征15%,磨旋征6%.结论环裂征是该病的特征性表现;双关节面征及葫芦征发现率较低,但特异性较高.椎管拉长征具有一定诊断价值,其它征象无论其发现率大小,均是该病的继发改变,不能作为确诊的直接依据.