Anterior Cervical Spine Surgery for Degenerative Disease: A Review

Anterior cervical spine surgery is an established surgical intervention for cervical degenerative disease and high success rate with excellent long-term outcomes have been reported. However, indications of surgical procedures for certain conditions are still controversial and severe complications to cause neurological dysfunction or deaths may occur. This review is focused mainly on five widely performed procedures by anterior approach for cervical degenerative disease; anterior cervical discectomy, anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, anterior cervical foraminotomy, and arthroplasty. Indications, procedures, outcomes, and complications of these surgeries are discussed.     

人工颈椎间盘置换术的研究进展

前路融合术是目前治疗颈椎病的常规术式,但颈椎前路融合术后邻近节段的退变加速越来越受到人们的重视。融合术还引起脊柱的生物力学改变,且存在植骨和内固定器械的并发症及供骨区慢性疼痛等。此外,颈椎前路手术的主要目标是解除脊髓的压迫而不是融合,这些都是困扰脊柱外科医师的难题。人工颈椎间盘置换术可在进行脊髓减压并提供稳定的同时保持手术节段颈椎的活动度,为颈椎病的外科治疗开辟了新的途径。本文结合最新文献对该技术的发展和前景进行综述。     

Careful follow-up after "successful" surgery: postoperative spondylolisthesis after anterior cervical corpectomy and fusion with instrumentation

BACKGROUND: Anterior cervical corpectomy and fusion with instrumentation is a common procedure for the surgical treatment of cervical spinal cord and/or nerve root decompression or for deformity correction. However, various postoperative complications have been associated with such a surgical intervention. Postoperative spondylolisthesis after an anterior cervical corpectomy with instrumentation is a serious complication that has rarely been addressed in the literature, and may potentially be underreported. CASE DESCRIPTION: A 44-year-old woman with degenerative disk disease, loss of cervical lordosis, congenital cervical stenosis at C5-C6, and a left-sided herniated disk at C6-C7 underwent an anterior cervical corpectomy of C6 with fusion and anterior plate stabilization of C5-C7. Early postoperative evaluation noted complete resolution of the patient's symptoms. At 6 months after surgery, the patient complained of neck pain and intermittent headaches. Radiographic evaluation noted fusion of the corpectomy strut graft with retrolisthesis of C5 on C6 and early myelomalacia at C5-C6. A cervical laminectomy with posterior instrumentation from C5 to C7 was performed and the patient's symptoms resolved. CONCLUSIONS: Postoperatively, a high index of suspicion should be present for the development of spondylolisthesis in patients undergoing an anterior cervical corpectomy and fusion procedure with or without instrumentation, particularly in individuals with persistent or new symptoms even after a "successful" operative procedure. The spine surgeon should address appropriate operative techniques and postoperative management to decrease the risk of spondylolisthesis after such a procedure.     

Material science and biomechanical interactions in cervical disc arthroplasty

Historically, anterior cervical discectomy and fusion (ACDF) has been the preferred surgical technique to address myelopathy and radiculopathy due to cervical spine intervertebral disc disease. Continued design improvements and theoretical biomechanical advantages to cervical disc arthroplasty over the last decade have made cervical disc arthroplasty an appealing alternative to ACDF, especially in younger patient populations without significant spondylosis who may wish to preserve neck motion. This narrative review will discuss the recent advances in cervical disc arthroplasty in regard to material composition, overall design and resultant degrees of freedom of the devices, the potential sparing of neck range of motion, and the theoretical biomechanical advantages of an arthroplasty compared to an ACDF.     

Anterior surgical treatment for cervical spondylotic myelopathy

Cervical spondylotic myelopathy is a disease of the cervical spine causing spinal cord compression secondary to spondylosis or ossification of the posterior longitudinal ligament. Anterior surgical options include anterior cervical discectomy and fusion, cervical corpectomy, and cervical disc arthroplasty. The surgeon must choose the right surgical option to decompress the cord, restore cervical lordosis, and adequately stabilize the spine. Although these surgical procedures are considered to be highly successful, each one is associated with complications. One must exercise great care when performing anterior cervical surgery and discuss with each patient the risks and benefits of the procedures.     

Laminectomy for multi-level cervical spondylotic myelopathy: Review of surgical indications,technique, and outcomes

The surgical management of multi-level cervical spondylotic myelopathy (CSM) continues to garner debate within the spine community with regards to optimal management. Options include anterior and posterior decompression, with several options available to the surgeon in either approach. The objective of this article is to review the indications, surgical technique, and outcomes of laminectomy with fusion and instrumentation in the management of multi-level CSM.     

The future in the care of the cervical spine: interbody fusion and arthroplasty. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2004

In the past 50 years tremendous advances have been made in the treatment of cervical disc disease with cervical fusion. Fusion rates have surpassed 95% after application of anterior cervical implants. Adjacent-segment degeneration, however, has plagued the long-term clinical success of cervical fusion. Cervical arthroplasty has been introduced to maintain cervical motion and potentially avoid or minimize adjacent-segment degeneration. If cervical arthroplasty is successful, the long-term results of surgery for cervical disc disease may improve; however, there are associated drawbacks that must be overcome. Implant wear, fatigue, and failure have been reported in cases of large-joint arthroplasty, and research is underway to limit these problems in cervical arthroplasty. In this article the authors trace the evolution of cervical fusion and the new technique of cervical arthroplasty. The nomenclature of cervical arthroplasty will also be introduced.     

Cervical disc arthroplasty: Equivalent alternative to anterior cervical discectomy and fusion but unknown superiority

Cervical disc arthroplasty has been developed as an alternative to anterior cervical discectomy and fusion with the advantages of preserving intervertebral motion, eliminating the risk of pseudarthrosis, and theoretically reducing adjacent segment degeneration. Several large prospective randomized trials have been conducted to investigate the clinical and radiographic results of cervical disc arthroplasty versus anterior cervical discectomy and fusion. Long-term results from these studies, however, show no difference in functional outcomes and no evidence to date in reduction of adjacent segment disease with arthroplasty. Although cervical disc arthroplasty is a safe and equivalent alternative, its superiority is yet unknown.     

Systematic review and meta-analysis of randomized controlled trials: comparison of total disk replacement with anterior cervical decompression and fusion

The authors performed a systematic review and meta-analysis to evaluate whether there is a beneficial clinical effect of total disk replacement compared with anterior cervical diskectomy and fusion for the treatment of single-level symptomatic cervical disk disease. A comprehensive literature search of multiple databases, including PubMed (1966-2011), Cochrane Controlled Trials Register (CENTRAL; issue 1, 2011), and Embase (1984-2011), was conducted to identify studies that met the inclusion criteria. Methodologic quality was assessed and relevant data were retrieved, and if appropriate, meta-analysis was performed. Eight randomized controlled trials were identified; six of the 8 reported 24-month follow-up results. At 24 months, total disk replacement was demonstrated to be more beneficial for patients compared with anterior cervical diskectomy and fusion for the following outcomes: overall success rate (odds ratio [OR], 1.79; 95% confidence interval [CI], 1.37-2.33; P<.0001), overall reoperation rate (OR,.36; CI, .21-.61; P=0), reoperation rate for revision (OR, .12; CI, .02 to .64; P=.01), and visual analog scale neck pain scores (standard mean differences [SMD], -.48; CI, -.91 to -.05; P=.03). Other outcomes, including Neck Disability Index scores (SMD, -.02; CI, -.44 to .27; P=.67) and visual analog scale arm pain scores (SMD, -.21; CI, -.63 to .22; P=.34), demonstrated no differences between the 2 groups. For patients with single-level symptomatic cervical disk disease, total disk replacement was found to be more effective than anterior cervical diskectomy and fusion in the 2 outcomes of overall success rate and overall reoperation rate at 24 months. Long-term results also showed total disk replacement trended to be more effective than anterior cervical diskectomy and fusion in some aspects.     

Is Cervical Disc Arthroplasty Superior to Fusion for Treatment of Symptomatic Cervical Disc Disease? A Meta-Analysis

Background

As the current standard treatment for symptomatic cervical disc disease, anterior cervical decompression and fusion may result in progressive degeneration or disease of the adjacent segments. Cervical disc arthroplasty was theoretically designed to be an ideal substitute for fusion by preserving motion at the operative level and delaying adjacent level degeneration. However, it remains unclear whether arthroplasty achieves that aim.

Questions/purposes

We investigated whether cervical disc arthroplasty was associated with (1) better function (neck disability index, pain assessment, SF-36 mental and physical health surveys, neurologic status) than fusion, (2) a lower incidence of reoperation and major complications, and (3) a lower risk of subsequent adjacent segment degeneration.

Methods

We conducted a comprehensive search in MEDLINE^®, EMBASE, and Cochrane Central Register of Controlled Trials and identified 503 papers. Of these, we identified 13 reports from 10 randomized controlled trials involving 2227 patients. We performed a meta-analysis of functional scores, rates of reoperation, and major complications. The strength of evidence was evaluated by using GRADE profiler software. Of the 10 trials, six trials including five prospective multicenter FDA-regulated studies were sponsored by industry. The mean followups of the 10 trials ranged from 1 to 5 years.

Results

Compared with anterior cervical decompression and fusion, cervical disc arthroplasty had better mean neck disability indexes (95% CI, −0.25 to −0.02), neurologic status (risk ratio [RR], 1.04; 95% CI, 1.00–1.08), with a reduced incidence of reoperation related to the index surgery (RR, 0.42; 95% CI, 0.22–0.79), and major surgical complications (RR, 0.45; 95% CI, 0.27–0.75) at a mean of 1 to 3 years. However, the operation rate at adjacent levels after two procedures was similar (95% CI, 0.31–1.27). The three studies with longer mean followups of 4 to 5 years also showed similar superiority of all four parameters of cervical disc arthroplasty compared with fusion.

Conclusions

For treating symptomatic cervical disc disease, cervical disc arthroplasty appears to provide better function, a lower incidence of reoperation related to index surgery at 1 to 5 years, and lower major complication rates compared with fusion. However, cervical disc arthroplasty did not reduce the reoperation rate attributable to adjacent segment degeneration than fusion. Further, it is unclear whether these differences in subsequent surgery including arthroplasty revisions will persist beyond 5 years.     

Types of anterior cervical grafts.

Anterior cervical diskectomy and fusion provide satisfactory results in most instances of cervical disk herniation and cervical spondylosis. A variety of interpositioned grafts have been described for such problems at one or two levels. Multiple level anterior decompression and fusion for patients with spondylotic myelopathy produce satisfactory results in most instances and are particularly effective when a degenerative kyphosis is present. Appropriate patient selection and attention to technical aspects of exposure, neural decompression, and graft procurement and placement directly influence the surgical outcome.     

锁定式颈椎融合器治疗单节段颈椎间盘突出症

目的探讨应用颈椎前路减压结合锁定式颈椎融合器治疗单节段颈椎间盘突出症的临床疗效。方法 21例单节段颈椎间盘突出症应用颈椎前路减压加锁定式颈椎融合器植骨融合术治疗,并对其疗效进行评价。结果所有病例随访12~24个月,平均17.6个月。6个月后椎体间均达到骨性融合,无并发症出现,脊髓功能状态评分术后1个月及术后6个月优良率分别达66.67%、85.71%。结论应用颈椎前路减压结合锁定式颈椎融合器治疗单节段颈椎间盘突出症疗效肯定。     

自锁式椎间融合器在一期后前路联合手术治疗脊髓型颈椎病中的应用(2年随访)

[目的]分析一期颈椎后路单开门椎管成型、前路椎间减压、自锁式椎间融合器自体植骨椎间融合术治疗脊髓型颈椎病的疗效.[方法]2006年9月～ 2008年4月,采用一期颈椎后路单开门椎管成型、前路椎间减压、自锁式椎间融合器自体植骨椎间融合术连续治疗脊髓型颈椎病52例;前路椎间减压单节段23例、双节段29例.记录患者术前及术后的JOA评分,在颈椎侧位X线片上测量椎间隙高度、椎间前凸角、颈椎前凸角的变化.[结果] 52例共随访24～40个月(平均30个月).52例患者在术后2周内均感到神经症状明显好转;没有发生手术相关并发症.术后6个月随访时,所有患者主诉四肢感觉、肌力、活动均较前明显改善,颈椎X线检查可见椎间已融合,椎间高度及生理曲度完好,无融合器移位、下沉、断裂发生.平均JOA评分由术前(7.3±0.5)分,提高到术后6个月(14.1±0.7)分,术后12个月(14.7±0.6)分,术后24个月(14.9±1.2)分;术后6个月随访时的JOA评分改善率:优21例,良25例,可6例,术后12个月及术后24个月时的JOA评分改善率与术后6个月无明显改变.[结论]采用一期颈椎后路单开门椎管成型、前路椎间减压、自锁式椎间融合器自体植骨椎间融合术治疗脊髓型颈椎病能获得颈髓前后方的充分减压及满意的临床疗效,能获得满意的颈椎曲度、稳定性重建及椎间融合.     

Hybrid cervical spine surgery for the treatment of multilevel cervical degenerative disc disease

The optimal surgical treatment for multilevel cervical degenerative disc disease is still controversial. The purpose of this article is to review the current evidence of the hybrid cervical surgery, which combines anterior cervical discectomy and fusion and cervical disc arthroplasty, for treating this condition. This fusion-nonfusion hybrid procedure provides favorable biomechanics and promising clinical and radiographic outcomes in both contiguous and skip-level pathologies. However, further high-quality and long-term follow-up studies are required to provide strong evidence and validate the results of the hybrid cervical spine surgery.     

颈前路减压融合钛板内固定治疗脊髓型颈椎病

目的讨论颈前路减压融合结合前路钛板内固定在脊髓型颈椎病治疗中的应用。方法回顾性分析62例脊髓型颈椎病选择颈前路减压（包括椎间盘切除和／或椎体次全切）融合及钛板内固定患者术后的治疗效果。所有患者术后随访2～4年,平均2．5年。结果术前及术后随访采用改良的JOA评分系统评价神经功能状况,术后神经功能恢复优良率为85．5％,椎间植骨融合率为100％。结论只要把握了手术时机和掌握了手术技巧,颈前路减压融合及钛板内固定是治疗脊髓型颈椎病安全而有效的方法。     

The NEtherlands Cervical Kinematics (NECK) Trial. Cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in the treatment of cervical disc herniation; a double-blind randomised multicenter study

Background  

Patients with cervical radicular syndrome due to disc herniation refractory to conservative treatment are offered surgical treatment. Anterior cervical discectomy is the standard procedure, often in combination with interbody fusion. Accelerated adjacent disc degeneration is a known entity on the long term. Recently, cervical disc prostheses are developed to maintain motion and possibly reduce the incidence of adjacent disc degeneration. A comparative cost-effectiveness study focused on adjacent segment degeneration and functional outcome has not been performed yet. We present the design of the NECK trial, a randomised study on cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in patients with cervical disc herniation.     

Complications and strategies for revision surgery in total disc replacement

Spinal arthroplasty is an acceptable alternative to fusion in many cases of disabling degenerative disc disease. Although arthroplasty has been demonstrated to be a safe and efficacious surgical option, complications related to the approach or the device may occur in few cases. Revision strategies for failed total disc arthroplasty can be planned as a posterior fusion, leaving the total disc replacement device in place, or by way of anterior removal with subsequent anterior fusion or revision replacement of the prosthesis.     

Motion preservation in cervical spine: review

Cervical disc replacement is an innovative technology that preserves motion at the instrumented level and has evolved as a potential alternative to spinal fusion for the treatment of cervical radiculopathy and myelopathy. Despite the excellent results of anterior cervical discectomy and fusion, arthroplasty allows for motion preservation which may be beneficial. Although the initial and midterm results from the randomized clinical trials demonstrated safety and equivalent clinical success as compared to anterior cervical fusion; the evidence establishing the superiority of arthroplasty over fusion in terms of preventing adjacent segment degeneration/disease is not available at this time.     

两种颈椎前路减压融合术治疗脊髓型颈椎病的临床疗效分析

[目的]回顾性分析比较椎间盘切除减压融合术(ACDF)和椎体次全切除减压融合术(ACCF)在治疗相邻两个节段脊髓型颈椎病的临床疗效及影像学数据.[方法]2005年4月～2007年8月,采用ACDF和ACCF治疗相邻两个节段脊髓型颈椎病156例.临床疗效采用日本骨科学会评分系统(JOA评分)对术前、末次随访的临床疗效进行评价.比较两组患者I临床疗效及手术时间、住院大数、术中失血量、颈椎活动度、颈椎曲度及节段性高度.[结果]两组的临床改善优良率无显著性差异(P＞0.05),ACDF组与ACCF组术中平均出血量及手术时间有显著性差异(P＜0.01),ACCF较ACDF增加,而ACCF组术后的节段性高度及颈椎前凸角较ACDF组明显降低(P＜0.01).[结论]ACDF与ACCF均能达到良好的手术疗效,然而ACDF在减少术中出血量、手术时间,改善和维持术后颈椎前凸角度及节段性高度较ACCF作用明显,但ACDF要求技术较高,有较长的学习曲线.     

Cervical kinematics after fusion and bryan disc arthroplasty

INTRODUCTION: Disc arthroplasty has been shown to provide short-term clinical results that are comparable with those attained with traditional anterior cervical discectomy and fusion. One proposed benefit of arthroplasty is the ability to prevent or delay adjacent level operations by retaining motion at the target level and eliminating abnormal adjacent activity. This paper compares motion parameters for single-level anterior cervical discectomy and fusion and disc replacement patients at the index level and adjacent segments. METHODS: Radiographic data from patients enrolled in a prospective, randomized clinical trial were selected for kinematic assessment of cervical motion. All patients received either a single-level fusion with allograft and anterior cervical plate (Atlantis anterior cervical plate, n=13) or a single-level artificial cervical disc (Bryan Cervical Disc prosthesis, n=9) at either C5/C6 or C6/C7. Flexion, extension, and neutral lateral radiographs were obtained preoperatively, immediately postoperatively, and at regular intervals up to 24-month time points. Cervical vertebral bodies were tracked on the digital radiographs using quantitative motion analysis software (QMA, Medical Metrics) to calculate the functional spinal unit motion parameters including range of motion (ROM), translation, and center of rotation. If visible, the functional spinal unit parameters were obtained at the operative level, and also the level above and the level below. RESULTS: As expected, significantly (P<0.006 at 3, 6, 12, and 24 mo) more flexion/extension motion was retained in the disc replacement group than the plated group at the index level. The disc replacement group retained an average of 6.7 degrees at 24 months. In contrast, the average ROM in the fusion group was 2.0 degrees at the 3-month follow-up and gradually decreased to 0.6 degrees at 24 months. The flexion/extension ROM both above and below the operative level was not statistically different for the disc-replaced and fusion patients, however, mobility increased for both groups over time. The anterior/posterior translation that occurs with flexion/extension motion remained unchanged for the disc replacement group at the level above the target disc preoperatively and postoperatively. In contrast, the translation increased for the level above the fusion. At the 6-month follow-up, the increase in translation was significantly greater for patients that were fused (P<0.02) than for patients that received a disc replacement. This change was not significant at 12 months. DISCUSSION: Previous studies have shown the Bryan disc to maintain mobility at the level of the prosthesis. The long-term clinical benefit of maintenance of motion is postulated to be the ability to delay or avoid adjacent level operations. This study reveals that there is no difference in flexion/extension ROM at the level above and below either a fusion or Bryan arthroplasty. There is, however, an increase in anterior/posterior translation at the cephalad adjacent level in patients with arthrodesis while the Bryan arthroplasty retains normal translation for the same amount of flexion/extension at the adjacent level. CONCLUSION: The Bryan disc may delay adjacent level degeneration by preserving preoperative kinematics at adjacent levels.