Biomechanical comparison of two different concepts for stand alone anterior lumbar interbody fusion

Segmental instability in degenerative disc disease is often treated with anterior lumbar interbody fusion (ALIF). Current techniques require an additional posterior approach to achieve sufficient stability. The test device is an implant which consists of a PEEK-body and an integrated anterior titanium plate hosting four diverging locking screws. The test device avoids posterior fixation by enhancing stability via the locking screws. The test device was compared to an already established stand alone interbody implant in a human cadaveric three-dimensional stiffness test. In the biomechanical test, the L4/5 motion segment of 16 human cadaveric lumbar spines were isolated and divided into two test groups. Tests were performed in flexion, extension, right and left lateral bending, right and left axial rotation. Each specimen was tested in native state first, then a discectomy was performed and either of the test implants was applied. Finite element analysis (FE) was also performed to investigate load and stress distribution within the implant in several loading conditions. The FE models simulated two load cases. These were flexion and extension with a moment of 5 Nm. The biomechanical testing revealed a greater stiffness in lateral bending for the SynFix-LR™ compared to the established implant. Both implants showed a significantly higher stiffness in all loading directions compared to the native segment. In flexion loading, the PEEK component takes on most of the load, whereas the majority of the extension load is put on the screws and the screw–plate junction. Clinical investigation of the test device seems reasonable based on the good results reported here.     

Absence of the mutated Trp2 allele but a common polymorphism of the COL9A2 collagen gene is associated with early recurrence after lumbar discectomy in a German population

Genetic factors seem to play a role in symptomatic lumbar disc disease (LDD). It has been shown previously that a tryptophan mutation of the COL9A2 gene is a major risk factor for LDD in a Finish population. The impact of collagen gene variations on the relapse rate after lumbar discectomy, however, has not been studied so far. Here, we conducted a cross-sectional genotyping study of patients who underwent lumbar discectomy to determine the influence of a COL9A2 mutation on the recurrence rates. Biopsy samples from 288 patients suffering from LDD with and without relapse were analyzed by PCR restriction fragment analysis and direct sequencing. The mutated Trp2 allele was not detected in the patients’ samples of the present study. However, nine patients with recurrent LDD, but only two without recurrence were homozygous for the Arg allele. Homozygosity for the Arg allele of Col9A2 seems to be more frequent in the patient group with early recurrence although the differences in the allele frequencies were statistically not significant. In contrast, the Trp2 mutation seems not to be a major susceptibility factor for LDD in a German population.     

Evaluation of morbidity,mortality and outcome following cervical spine injuries in elderly patients

We analysed the morbidity, mortality and outcome of cervical spine injuries in patients over the age of 65 years. This study was a retrospective review of 107 elderly patients admitted to our tertiary referral spinal injuries unit with cervical spine injuries between 1994 and 2002. The data was acquired by analysis of the national spinal unit database, hospital inpatient enquiry system, chart and radiographic review. Mean age was 74 years (range 66–93 years). The male to female ratio was 2.1:1 (M = 72, F = 35). The mean follow-up was 4.4 years (1–9 years) and mean in-hospital stay was 10 days (2–90 days). The mechanism of injury was a fall in 75 and road traffic accident in the remaining 32 patients. The level involved was atlanto-axial in 44 cases, sub-axial in 52 cases and the remaining 11 had no bony injury. Multilevel involvement occurred in 48 patients. C2 dominated the single level injury and most of them were type II odontoid fractures. Four patients had complete neurology, 27 had incomplete neurology, and the remaining 76 had no neurological deficit. Treatment included cervical orthosis in 67 cases, halo immobilization in 25, posterior stabilization in 12 patients and anterior cervical fusion in three patients. The overall complication rate was 18.6% with an associated in-hospital mortality of 11.2%. The complications included loss of reduction due to halo and Minerva loosening, non-union and delayed union among conservatively treated patients, pin site and wound infection, gastrointestinal bleeding and complication due to associated injuries. Among the 28.9% patients with neurological involvement, 37.7% had significant neurological recovery. Outcome was assessed using a cervical spine outcome questionnaire from Johns Hopkins School of Medicine. Sixty-seven patients (70%) completed the form, 20 patients (19%) were deceased at review and 8 patients (7%) were uncontactable. Functional disability was more marked in the patients with neurologically deficit at time of injury. Outcome of the injury was related to increasing age, co-morbidity and the severity of neurological deficit. Injuries of the cervical spine are not infrequent occurrence in the elderly and occur with relatively minor trauma. Neck pain in the elderly patients should be thoroughly evaluated to exclude C2 injuries. Most patients can be managed in an orthosis but unstable injuries require rigid external immobilization or surgical stabilization.     

Novel diagnosis and subsequent management of a very large Giant Cell Tumour of bone arising as a rarity in the thoracic spine

A 34-year-old male, who presented with mild upper back pain of recent onset was discovered to have a large intrathoracic mass, which was in continuity with tumour which had extensively destroyed the T5 and T6 vertebrae. Microscopy of an aspirated pleural effusion unexpectedly revealed many large multinucleated giant cells and the subsequent needle biopsy confirmed the diagnosis of a Giant Cell Tumour (GCT) of bone. In addition to being the first reported occasion when a GCT has been provisionally diagnosed by cytological examination of a pleural effusion, this case report also considers the unusual features and unpredictable behaviour of a tumour, which very rarely originates in the thoracic spine. The complex and prolonged surgical procedure adopted to extirpate tumour, which had permeated important mediastinal structures and to restore stability to the spinal column is outlined.     

内镜辅助微创入路人工腰椎间盘置换术的临床效果及矢状平衡分析

目的 探讨内镜辅助微创入路人工腰椎间盘置换术的临床效果及对矢状平衡的影响.方法 采用内镜辅助微创入路Maverick人工腰椎间盘置换术治疗腰椎间盘退变性疾病135例.术前MR检查评估小关节和椎旁肌退变程度;术前和随访时均摄腰椎正侧位、过伸过屈位及包括双侧股骨头的站立位脊柱全长正侧位X线片,测量假体位置和活动度、矢状平衡参数.结果 术后随访2～5年,平均3.5年.一个间隙手术时间平均60 min,术中出血平均170 ml.输尿管损伤1例,术中修补后效果好,交感神经损伤5例,术后神经根性痛4例,切口浅表感染1例,保守治疗后均好转.末次随访时Oswestry 评分由术前平均46.6%+12.0%降至23.2%±19.0%;腰痛和腿痛视觉类比评分(visual analogue scale,VAS)分别由术前平均7.6±2.3和3.6±3.0降至2.7±2.5和1.9+2.5.末次随访时间盘置换节段活动度平均7.5°±5.2°,节段性前凸较术前增加,但相邻节段前凸代偿性减少,腰椎前凸轻度增大,维持矢状平衡.L4-5 椎间盘置换同时行L5S1前路融合者L4,5前凸增大不明显;L5S1椎间盘置换者骨盆指数平均降低1.7°;骶骨上终板倾角＜35°者末次随访时平均增大2.1°,＞45°者平均减少3.8°.结论 内镜辅助微创人路Maverick人工腰椎间盘置换术在严格掌握适应证的情况下能取得良好的临床效果,保留椎间活动度,恢复和保持脊柱矢状平衡,间盘置换节段一般前凸增加,但受相邻节段融合手术的影响.     

Use of stand-up magnetic resonance imaging for evaluation of a cervicothoracic injury in a patient with ankylosing spondylitis

BACKGROUND CONTEXT: Injuries at the cervicothoracic junction are common in patients with ankylosing spondylitis. These injuries present challenges for both initial and follow-up imagings. PURPOSE: To describe a case of a patient with ankylosing spondylitis who was treated with laminectomy and a cervicothoracic orthosis for a spinal epidural hematoma after a nondisplaced fracture at the cervicothoracic junction and to discuss the merits of stand-up magnetic resonance imaging (MRI) for follow-up evaluation of this type of injury. STUDY DESIGN/SETTING: Case report. METHODS: Clinical data of a patient with ankylosing spondylitis who sustained a nondisplaced C7 fracture are presented, followed by a detailed review of the literature concerning imaging techniques available for the evaluation of cervical spine trauma in this patient population. RESULTS: The patient was treated with emergent laminectomy and evacuation of the epidural hematoma, followed by definitive management in a cervicothoracic orthosis secondary to medical comorbidities. The patient was then successfully followed postoperatively with stand-up MRI because conventional imaging techniques could not adequately image the injury level in an upright position. CONCLUSIONS: Cervicothoracic injuries are common in patients with ankylosing spondylitis and may be difficult to follow with conventional imaging techniques. Stand-up MRI is a relatively new modality that may offer significant advantages over conventional imaging because of the ability to evaluate the cervicothoracic junction in a more functional position and the lack of a confining space such as that found in standard MRI units.     

成人齿状突骨折的治疗策略

对于齿状突骨折的治疗目前无一致意见,且尚无充分证据支持骨折的非手术或手术治疗选择.影响骨折愈合的因素包括骨折平面、是否移位和移位程度以及患者的年龄,笔者建议的手术适应证包括明显移位或成角、年龄>50岁、ⅡA型骨折、非手术治疗不能维持骨折稳定和陈旧性骨折.手术治疗应尽量选择前路螺钉内固定而避免融合.     

腰椎退变性侧凸的治疗策略

目的探讨非手术治疗或腰椎后路减压、矫形固定、融合手术治疗由于椎间盘退变后继发小关节退变、椎管和神经根管容积变化以及脊柱失稳、畸形等病理改变导致的腰椎退变性侧凸患者的效果。方法2001年7月-2007年6月，治疗退变性腰椎侧凸患者56例，其中行非手术治疗5例。手术治疗51例。手术组患者平均年龄为63岁，腰椎侧凸Cobb角平均30°，采用腰椎后路减压，或辅助椎弓根螺钉矫形固定、后外侧融合或椎间融合治疗。结果56例均得到随访，平均随访时间为20个月，非手术治疗和手术患者均对治疗效果满意，生活质量提高，手术组矫正角度平均为15°，骨融合率达到95％，无神经损伤及翻修病例。结论腰椎退变性侧凸首选非手术治疗，如失败应根据患者情况遵循尽量采用有限内固定和融合的原则行手术治疗。     

Conservative treatment of tuberculosis of the thoracic and lumbar spine in adults and children

Summary We have treated 75 cases of spinal tuberculosis with chemotherapy as outpatients. The drugs used were INH, rifampicin and ethambutol for the 48 adults, and INH, rifampicin and PAS for the 27 children. No operations, apart from the evacuation of large abscesses, were carried out. Every patient was followed up for at least three years and the outcome was judged to be favourable in 95%. This is better than in some series in which radical surgery has been used. Although we recognize the advantages of operation in certain circumstances, we believe that our conservative regimen can be confidently recommended for use in less privileged countries, where adequate facilities for hospital treatment may not be available.

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Résumé Nous avons traité médicalement, en malades externes, 75 cas de tuberculose rachidienne. Les médicaments utilisés ont été INH, Rifampicine et Ethambutol chez les 48 adultes, et INH, Rifampicine et PAS chez les 27 enfants. Aucune intervention, hormis l'évacuation d'abcès volumineux, n'a été réalisée. Tous les malades ont été suivis au moins trois ans et le résultat a été jugé bon dans 95% des cas. Ceci est meilleur que certaines séries où l'on a eu recours à une chirurgie radicale. Bien que nous reconnaissions les avantages du traitement chirurgical dans certains cas, nous pensons que notre traitement conservateur peut être recommandé en toute confiance dans les pays tels que la Corée qui ne disposent pas des moyens nécessaires pour soigner ces malades en milieu hospitalier.