腰椎非融合技术研究进展

腰椎融合术作为脊柱外科治疗腰椎退行性疾病的经典术式,发展至今已有百余年历史。通过坚强的椎弓根钉内固定加上椎间融合技术可以获得很高的责任节段融合率,但其也存在一些问题,最为突出的是相邻节段会分担更多的应力,应力增加会造成退变加速。腰椎非融合技术最大优势在于保留责任节段活动度,从而维持腰椎的生物力学稳定性,减缓邻近节段退变速度。目前临床应用较多的非融合技术有人工髓核及椎间盘置换术、棘突间动态固定系统、经椎弓根动态固定系统等。该文就腰椎非融合技术研究进展进行综述。     

Dynesys动态稳定系统与腰椎退变性疾病

传统的脊柱融合术是治疗腰椎退变性疾病的金标准.越来越多证据表明,融合后腰部活动受限制、脊柱动力学改变和邻近节段加速退变可导致腰椎不稳和椎管狭窄复发.非融合技术也称为动态固定,开始受到关注.非融合固定可通过非融合方法有效改善腰椎节段间的应力传导,缓解疼痛并预防邻近关节退变的发生,其远期效果在于异常活动被控制后,椎间盘在动态固定保护下可自身修复或延缓退变.绝大多数临床结果显示,非融合疗效与传统融合术相当,但创伤较小,不会增加邻近节段继发退变等风险,更符合脊柱生理性稳定.该文主要介绍后路经椎弓根动态稳定系统Dynesys的设计理念、治疗原理、临床应用及治疗效果等.     

棘突间固定系统与融合固定系统联合应用治疗腰椎退变性疾患

[目的]探讨棘突间固定系统与融合固定系统联合应用治疗腰椎退变性疾病的临床疗效.[方法]2007年2月～2009年2月本院收治的90例腰椎退变性疾病患者90例,分为棘突间固定系统与融合固定系统联合应用组和单纯棘突间固定系统应用组,各45例.分别对两组患者术后即时疗效进行评价.术后定期随访(30 ～ 54个月),分别对两组患者不良预后指标进行评估.[结果]两组患者术后即时疗效相比,联合应用组总有效率(93.3％)明显优于单纯应用组(75.6％)(P＜0.05).从随访结果分析看,联合应用组不良预后发生率显著低于单纯应用组(P＜0.05).[结论]棘突间固定系统与融合固定系统联合应用治疗腰椎退变性疾病较单纯棘突间固定系统应用具有更好的临床治疗效果.     

腰椎后路非融合固定系统的临床应用进展

融合术是治疗脊柱退变的金标准,但融合后会产生一系列问题[1]。因此,有人提出了非融合固定的概念,也可称为动态固定系统,即保留有益运动和节段间负荷传递的稳定系统,不做椎体间融合。     

后路短节段固定治疗胸腰椎骨折是否需要融合?

目的 探讨后路短节段固定治疗胸腰椎骨折是否需要植骨融合.方法 采用伤椎相邻的上下椎椎弓根钉固定+伤椎上应用垂直应力螺钉的方法治疗120例单节段胸腰椎骨折.其中60例为非融合组,60例为后外侧融合组.结果 融合组和非融合组的临床疗效和影像学结果比较无统计学差异;融合组的手术出血量和手术时间明显大于非融合组(P＜0.05).结论 单节段胸腰椎骨折同时有椎间盘或后方韧带复合体损伤时,在后路椎弓根固定时最好行融合手术,否则不需融合.     

Cosmic动态非融合系统治疗腰椎退变性疾病的短期疗效分析

目的探讨Cosmic动态非融合系统在腰椎退变性疾病治疗中的短期疗效。方法对22例腰椎退变性疾病在后路减压的同时行Cosmic动态非融合系统内固定术,并评价术后疗效。结果术后随访8~24个月,平均14.5个月,术后临床疗效优17例、良4例,可1例。VAS疼痛评分术前(6.74±0.59)分,末次随访时(2.13±0.61)分。术前病变脊柱运动节段过伸过屈活动度(ROM)(8.39±2.72)°,末次随访时为(8.17±2.58)°。随访期间未见内固定松动和螺钉断裂现象。结论采用Cosmic动态非融合内固定系统治疗腰椎退变性疾患具有手术操作简便、安全性高等优点,可减少对脊柱生理结构的破坏,维持节段稳定,减少远期腰椎退变和再次手术的风险,具有很好的临床应用前景。     

峡部螺钉联合非融合椎弓钉固定腰椎峡部裂

[目的] 探讨峡部螺钉结合非融合椎弓钉固定治疗腰椎峡部裂的临床疗效。[方法] 2015年1月—2019年6月,应用峡部螺钉结合非融合椎弓钉固定治疗腰椎峡部裂或伴Ⅰ度滑脱或盘源性腰痛的患者21例,观察临床与影像结果。[结果] 21例患者均顺利完成手术,术中无血管、神经损伤、脑脊液漏等并发症发生,手术时间平均（130.15±29.72）min,术中出血量平均（215.64±58.51）ml。所有患者均获随访（32.62±9.43）个月,随时间推移,患者VAS和ODI评分较术前明显减少（P<0.05）。术后18个月峡部裂骨性融合率为100%。末次随访时UCLA系统评价与术前相同,未发现邻近节段退变加重情况。[结论] 峡部螺钉结合非融合椎弓钉固定治疗腰椎峡部裂或伴Ⅰ度滑脱或盘源性腰痛是安全有效的,峡部融合率满意。     

DRFS系统治疗腰椎滑脱症临床疗效观察

目的：探讨应用脊柱滑脱掉开复位系统(divided reducible fixed system,DRFS)加后路植骨治疗腰椎滑脱症的临床疗效。方法：应用后路DRFS提拉复何内固定系统结合椎体植骨融合治疗腰椎滑脱症20例。结果：术后全部20例病人均获得解剖复位,术后随访6～18个月,滑脱椎复位无丢失,椎体植骨融合牢固。结论：DRFS提拉复位内固定系统可提供满意的椎体复位固定作用,并能保证和促进植骨的融合,从而明显地提高融合率。     

动力性固定系统在下腰痛治疗中的应用

退变性慢性下腰痛的传统治疗方法脊柱融合技术的发展大大提高了融合率,但临床效果却没有相应提高.这一现象促使脊柱外科医生思考引起慢性下腰痛的真正原因及应用非融合技术治疗腰椎退变性疾病的可能性.近10余年来,国外一些学者相继开始尝试使用动力性固定系统治疗下腰痛.虽然迄今还没有任何一种器械在治疗机制上有完备的生物力学基础,也没有很强有力的临床证据证明其有效,但是近期一些临床报道还是不乏成功的例子,所用器械在治疗理论上的优势使得它们值得关注.     

动态稳定非融合技术与后路固定融合技术治疗老年退变性脊柱侧弯的对比研究

椎弓根钉棒矫形固定+后外侧融合是治疗老年退变性脊柱侧弯最常用的方法,但大量临床报道各类并发症较高。近年来动态稳定系统非融合技术受到了广泛的关注,却鲜有治疗退变性脊柱侧弯的报道。为了明确动态稳定非融合技术与后路固定融合技术治疗老年退变性     

腰椎后路非融合固定系统的临床应用进展

腰椎椎间盘与关节突关节退变是引起腰痛和腰椎不稳的主要原因,在以往对非手术治疗无效的患者通常是采用融合固定术。椎弓根螺钉固定和椎间融合器植骨融合是最常用的技术,融合率可达到90%～100%,但融合固定后所产生的异常应力集中于邻近椎间盘及关节突,将产生邻近未融合节段的运动范围异常增加及相关病理性变化,从而导致继发性椎管狭窄、关节突关节退变、获得性腰椎滑脱、不稳等     

Risk Factors of Nonfusion after Anterior Cervical Decompression and Fusion in the Early Postoperative Period: A Retrospective Study

Objective

Although high fusion rates have been reported for anterior cervical decompression and fusion (ACDF) in the medium and long term, the risk of nonfusion in the early period after ACDF remains substantial. This study investigates early risk factors for cage nonfusion in patients undergoing single- or multi-level ACDF.

Methods

This was a retrospective study. From August 2020 to December 2021, 107 patients with ACDF, including 197 segments, were enrolled, with a follow-up of 3 months. Among the 197 segments, 155 were diagnosed with nonfusion (Nonfusion group), and 42 were diagnosed with fusion (Fusion group) in the early period after ACDF. We assessed the significance of the patient-specific factors, radiographic indicators, serum factors, and clinical outcomes. The Wilcoxon rank sum test, t-tests, analysis of variance, and stepwise multivariate logistic regression were used for statistical analysis.

Results

Univariate analysis showed that smoking, insufficient improvement in the C2-7 Cobb angle (p = 0.024) and the functional spinal unit Cobb angle (p = 0.022) between preoperative and postoperative stages and lower serum calcium (fusion: 2.34 ± 0.12 mmol/L; nonfusion: 2.28 ± 0.17 mmol/L, p = 0.003) β-carboxyterminal telopeptide end of type 1 collagen (β-CTX) (fusion: 0.51 [0.38, 0.71]; nonfusion: 0.43 [0.31, 0.57], p = 0.008), and N-terminal fragment of osteocalcin (N-MID-BGP) (fusion: 18.30 [12.15, 22.60]; nonfusion: 14.45 [11.65, 18.60], p = 0.023) are risk factors for nonfusion in the early period after ACDF. Stepwise logistic regression analysis revealed that poor C2-7 Cobb angle improvement (odds ratio [OR], 1.107 [1.019–1.204], p = 0.017) and lower serum calcium (OR, 3.700 [1.138–12.032], p = 0.030) are risk factors.

Conclusions

Patients with successful fusion after ACDF had higher preoperative serum calcium and improved C2-7 Cobb angle than nonfusion patients at 3 months. These findings suggest that serum calcium could be used to identify patients at risk of nonfusion following ACDF and that correcting the C2-7 Cobb angle during surgery could potentially increase fusion in the early period after ACDF.     

Motion preservation technologies: alternatives to spinal fusion

Spinal arthrodesis is a versatile and effective option in the management of instabilities, deformities, and painful spinal conditions. An increasing body of biomechanical and clinical evidence suggests that the relative immobility of fused spinal segments alters stress transfer, leading to adjacent-level degeneration. The development of nonfusion spinal prostheses has been driven by increasing concerns regarding these arthrodesis-related morbidities, including graft-site harvest, pseudarthrosis, and adjacent-level degeneration. Motion-sparing implants offer some theoretical advantages over fusion; however, judicious use of these products with careful patient selection is warranted until outcome studies can demonstrate their efficacy. In this article, we review the 3 major categories of nonfusion technologies: total disc replacement, prosthetic nuclear implants, and posterior stabilization devices.     

Results of L4-L5 disc excision alone versus disc excision and fusion

We evaluated the results of 85 patients having L4-L5 disc excision (52 having disc excision alone, and 33 having disc excision and fusion) using the Smiley-Webster scale at an average follow-up of 7.3 years. Both groups (fusion and nonfusion) were comparable except that the nonfusion group had a significantly higher percentage of patients with a history of chronic back pain and degenerative changes on their initial radiographs. The fusion group had significantly better results compared with the nonfusion group (85% satisfactory results versus 39% satisfactory results). The most common cause of unsatisfactory results in the fusion group was pseudarthrosis (two) while progressive degenerative disc disease (18) and recurrent disc prolapse (eight) were the most common cause of unsatisfactory results in the nonfusion group. The overall reoperation rate was 9.4% (13.5% in the nonfusion group, and 3% in the fusion group.     

Clinical and radiographic evaluation of disc excision for lumbar disc herniation with and without posterolateral fusion

STUDY DESIGN: A prospective study evaluating the clinical and radiographic results in 95 patients with lumbar disc herniation. OBJECTIVES: To evaluate the results of disc excision, with and without posterolateral fusion. SUMMARY OF BACKGROUND DATA: The effect of posterolateral fusion on the outcomes and radiologic changes in patients with lumbar disc herniation has rarely been reported. METHODS: Forty-four patients underwent disc excision, and 51 patients underwent disc excision and fusion. Clinical symptoms were evaluated using the Japanese Orthopaedic Association Back scores. All medical and surgical records were examined with regard to intraoperative blood loss, operation time, and other data. Preoperative and follow-up radiographs were analyzed to determine the spinal motion and disc height. RESULTS: Clinical outcome was excellent or good in 73% of the nonfusion group and in 82% of the fusion group (P = 0.31). The reduction in lower back pain after surgery was greater in the fusion group. The rate of recurrent disc herniation at the surgical level in the nonfusion group increased, but intraoperative blood loss, operation time, length of hospital stay, and total cost of procedure were all significantly less in the patients undergoing disc excision alone than in the fusion group. The radiologic analysis provided evidence that the disc height at the level of disc excision and posterolateral fusion in the fusion group decreased with time, as in the nonfusion group. The changes in disc height and spinal motion were not related to the clinical results. CONCLUSIONS: Although there is still controversy regarding the pros and cons of fusion in association with disc excision, there is seldom an indication for primary fusion for lumbar disc herniation.     

Advantages and disadvantages of nonfusion technology in spine surgery

Nonfusion technology in spine surgery may improve outcomes by reducing surgical morbidity and the incidence of adjacent level degeneration; however, new technologies also introduce new short- and long-term complications. There is currently no evidence that nonfusion implants are superior to fusion in mid- to long-term follow-up. Understanding the potential risks and benefits of nonfusion technology is essential for spine surgeons and their patients. This article reviews the current evidence relating to the potential risks and benefits of nonfusion technology in spine surgery.     

A comparison of radiographic findings in fusion and nonfusion patients ten or more years following lumbar disc surgery

Ninety-six patients who had undergone disc excision and midline spinal fusion and 36 patients who had had simple disc excision had spinal radiographs made 10 or more years postoperatively. Claw spurs were found most commonly at the L2-3 and L3-4 levels in fusion patients, particularly male laborers. Traction spurs with segmental hypermobility were found more commonly at the L4-5 level in patients whose spines were not fused, particularly women. Total lumbar flexion-extension was greater in nonfusion than in fusion patients, but the L1-3 mobility was greater in those who had undergone fusion, suggesting a compensatory increase in the range of lumbar motion. Segmental mobility at levels of surgery in nonfusion patients was similar in those with good and those with poor clinical results. Disc space narrowing was common at levels of operation, but did not correspond to the clinical result. Pseudarthrosis was demonstrated in 26% of fusion patients, but was of no clinical significance. Although complex radiographic changes follow lumbar disc surgery, with or without failure, it is concluded that the plane radiograph is of little aid in determining the source of postoperative pain. The sole exception is that of acquired spondylolysis, which was found in 2.5% of this group of fusion patients, and was clearly associated with a poor clinical outcome. Symptomatic degenerative disc disease at levels above lumbar spinal fusions appears to be an uncommon clinical problem.     

Which procedure is better for lumbar interbody fusion: anterior lumbar interbody fusion or transforaminal lumbar interbody fusion?

Introduction

Both anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) surgeries are performed to obtain a solid fusion to treat lumbar spondylosis. This systematic review investigated whether surgical complications, nonfusion rate, radiographic outcome, and clinical outcome of ALIF were significantly different from those of TLIF.

Method

A computerized search of the electronic databases MEDLINE was conducted. Only therapeutic studies with a prospective or retrospective comparative design were considered for inclusion in the present investigation. Two reviewers independently extracted relevant data from each included study. Statistical comparisons were made when appropriate.

Results

Nine studies were determined to be appropriate for the systematic review, and all studies were retrospective comparative studies. Blood loss and operative time in ALIF was greater than in TLIF. There was no significant difference in the complication rate between ALIF and TLIF. The restoration of disc height, segmental lordosis, and whole lumbar lordosis in ALIF was superior to TLIF. However, clinical outcomes in ALIF were similar with TLIF, and there was no significant difference in nonfusion rate between the two techniques. Costs of ALIF were greater than those of TLIF.

Conclusion

Clinical outcomes and nonfusion rate in ALIF were similar to TLIF. However, the restoration of disc height, segmental lordosis, and whole lumbar lordosis in ALIF were superior to those in TLIF, while blood loss, operative time, and costs in ALIF were greater than in TLIF.     

Biomechanics of nonfusion implants

Although spine fusion is a versatile and effective technique in the treatment of spinal disorders, increased stresses on adjacent unfused levels lead to symptomatic adjacent level degeneration in many patients. The goal of nonfusion devices in spine surgery is to ablate or unload painful structures while preserving segmental motion. The intended performance of nonfusion devices such as disc replacement, nucleus pulposus replacement, and posterior stabilization devices can be understood from the biomechanics of the functional spinal unit in health and disease and the interplay between the motion segment and the device. Implant design issues can also markedly affect performance.     

A comparison of dynamic views using plain radiographs and thin-section three-dimensional computed tomography in the evaluation of fusion after posterior lumbar interbody fusion surgery

Background context

Accurate evaluation of the postsurgery status of interbody fusion is important in deciding the patient's treatment. Dynamic plain radiographs are used as a convenient method, but the accuracy is not so good.

Purpose

This study aimed to evaluate the usefulness of dynamic flexion-extension radiographs as a method for evaluating fusion, by comparing it with three-dimensional thin-section computed tomography (CT).

Study design

Prospective controlled study.

Methods

We conducted a prospective study with 108 patients (158 levels) who, diagnosed with severe spinal stenosis and Grade I and Grade II spondylolisthesis, underwent posterior lumbar interbody fusion (PLIF) surgery, with follow-up by dynamic plain radiographs, functional rating scale, and three-dimensional (3D) thin-section CT for 1 year after surgery. In the plain radiographs, we looked for less than 3° of lordotic angle change, less than 3 mm of translation between vertebral bodies, and no presence of halo signs; satisfying all the criteria was regarded as fusion (Group A), whereas failure to satisfy any condition was referred to as probable nonfusion (Group B) and if none were satisfied as nonfusion (Group C). The patients were classified into fusion or nonfusion groups based on CT. Correlation between plain radiographs and CT groups was analyzed. Moreover, clinical assessment and cross-comparison between observers were done.

Results

In 158 levels, 95 (60.8%) levels were classified into the fusion group by plain radiographs and 131 (83%) levels by CT. When we analyzed the results of each groups, in Group A, 78 (81.3%) levels belonged to the CT fusion group and 18 (18.7%) levels to the CT nonfusion group, in Group B, 51 (89.5%) and 6 (10.5%) levels, and in Group C, 2 (40%) and 3 (60%) levels, respectively. For each of the CT fusion group, a cross-comparison using dynamic radiographs reconfirmed 78 (59.5%) levels for Group A, 51 (38.9%) levels for Group B, and 2 (1.6%) levels for Group C; for the CT nonfusion groups, 18 (66.7%) levels, 6 (22.2%) levels, and 3 (11.1%) levels were for Groups A, B, and C, respectively. In clinical evaluation, all groups showed clear postsurgery improvement, but there was no statistically significant difference. In terms of observer-to-observer error and agreement between diagnoses, CT showed a statistically higher level of correlation than plain radiographs.

Conclusions

Dynamic flexion-extension radiographs cannot be seen as an objective standard in the evaluation of fusion after PLIF surgery. It would be desirable to confirm the fusion status by thin-section 3D-CT for an objective analysis.