Effects of a cervical disc prosthesis on maintaining sagittal alignment of the functional spinal unit and overall sagittal balance of the cervical spine

The object of this study is to review the early clinical results and radiographic outcomes following insertion of the Bryan Cervical Disc Prosthesis (Medtronic Sofamor Danek, Memphis, TN), together with its effect on maintaining sagittal alignment of the functional spinal unit (FSU) and overall sagittal balance of the cervical spine for the treatment of single-level or two-level symptomatic disc disease. Forty-seven patients with symptomatic single or two-level cervical disc disease who received the Bryan Cervical Artificial Disc were reviewed prospectively. A total of 55 Bryan disc were placed in 47 patients. A single-level procedure was performed in 39 patients and a two-level procedure in the other eight. Radiographic and clinical assessments were made preoperatively and at 1.5, 3, 6, 9, 12, and 18 and up to 33 months postoperatively. Mean follow-up duration was 24 months, ranging from 13 to 33 months. Periods were categorized as early follow up (1.5–3 months) and late follow up (6–33 months). The visual analogue scale (VAS), neck disability index(NDI), Odom’s criteria were used to assess pain and clinical outcomes. Static and dynamic radiographs were measured by hand and computer to determine the range of motion (ROM), the angle of the functional segmental unit (FSU), and the overall cervical alignment (C2–7 Cobb angle). With all of these data, we evaluated the change of the preoperative lordosis (or kyphosis) of the FSU and Overall sagittal balance of the cervical spine during the follow-up period. There was a statistically significant improvement in the VAS score from 7.0 ± 2.6 to 2.0 ± 1.5 (paired-t test, P = 0.000), and in the NDI from 21.5 ± 5.5 to 4.5 ± 3.9 (paired-t test P = 0.000). All of the patients were satisfied with the surgical results by Odom’s criteria. The postoperative ROM of the implanted level was preserved without significant difference from preoperative ROM of the operated level. Only 36% of patients with a preoperative lordotic sagittal orientation of the FSU were able to maintain lordosis following surgery. However, the overall sagittal alignment of the cervical spine was preserved in 86% of cases at the final follow up. Interestingly, preoperatively kyphotic FSU resulted in lordotic FSU in 13% of patients during the late follow-up, and preoperatively kyphotic overall cervical alignment resulted in lordosis in 33% of the patients postoperatively. Clinical results are encouraging, with significant improvement seen in the Bryan Cervical Artificial disc. The Bryan disc preserves motion of the FSU. Although the preoperative lordosis (or kyphosis) of the FSU could not always be maintained during the follow-up period, the overall sagittal balance of the cervical spine was usually preserved.     

Single level cervical arthroplasty with the Discocerv prosthesis: a preliminary report

The authors conducted a prospective nonrandomised study about a new cervical disc prosthesis: the Discocerv Cervidisc Evolution. Fourteen patients (10 men and 4 women) were treated at a single mobile level, between July 2006 and November 2008. Their mean age was 40.8 years (range 31-56), and the mean clinical follow-up period was 12.8 months (range 9-18). Diagnosis was disc herniation (n = 12) and stenosis (n = 2). The VAS for neck pain, the VAS for radiating pain and the Neck Disability Index decreased significantly at last followup (p <0.05). According to Odom's criteria 81.6% of the patients had a good or excellent outcome. The range of movement of the cervical spine as a whole and of the treated functional segmental unit were preserved at final follow-up, which suggests that the disc prosthesis might prevent osteoarthritis at adjacent levels. The neutral sagittal alignment of the cervical spine as a whole and of the functional spinal unit showed kyphosis shortly after surgery, but lordosis was practically restored at final follow-up.     

Clinical and radiographic reports following cervical arthroplasty: a 24-month follow-up

We reviewed patients with cervical disc prosthesis replacement for single-level cervical disc disease to evaluate its clinical effect and maintenance of cervical spine motion. Fifteen patients underwent Bryan artificial cervical disc replacement and were followed-up for at least 24 months. No neurological or vascular complications were observed during or after operation. JOA, VAS, and NDI scores showed statistical significant improvement in our follow-up. The procedure achieved an 87% (13/15) satisfactory rate at 24-month evaluations according to Odom's criteria. The range of motion (ROM) of the cervical spine, treated segment, adjacent segment, and functional spinal unit (FSU) decreased at early follow-up, but they recovered to the preoperative level at 12- and 24-month follow-up. Also, preoperative lordosis of the cervical spine and FSU were not only maintained but also even improved during the 24-month follow-up. No obvious degeneration of adjacent discs were found at MRI. There were no cases of prosthesis subsidence or extrusion. The cervical disc prosthesis showed a good clinical outcome; it also restored ROM of the cervical spine and reestablished cervical curvature in our 24-month follow-up. But to be sure of its long term effect, a longer follow-up is needed.     

Early clinical and radiologic outcomes of cervical arthroplasty with Bryan Cervical Disc prosthesis

Among 61 patients underwent disc replacement with the Bryan prosthesis, 47 patients were followed more than 3 months and their clinical and radiologic data were retrospectively analyzed to clarify very early clinical and radiologic outcomes and complications of disc arthroplasty with the Bryan Cervical Disc prosthesis during the learning period. Mean follow-up period was 6 months. Mean age was 45.6 years. Single-level procedure was done in 39 patients and 2-level in 8; a total of 55 levels replaced. Neck disability index improved from 59.8% to 22.9%. Visual analog pain score (VAS) of the neck improved from 8.4 to 1.6. VAS of shoulder/arm pain improved from 8.8 to 2.4. Mean patients' subjective improvement rate of symptoms was 71.1%. According to improvement in the neck disability index and VAS (over 50% improvement rate in each parameter), patients' subjective improvement rate (over 50%), and patients' satisfaction, the surgical success was achieved in 39 patients (83%). Eight patients (17%) showed failure. Mean segmental angle became more kyphotic after surgery from -0.7 degree of kyphosis (-11 to 7.7 degrees) to -1.3 degrees (-32 to 20.9 degrees) without statistical significance (P=0.55). Among 24 segments that showed preoperative kyphosis, 13 (54.2%) showed aggravated kyphosis, 7 (29.1%) showed decreased kyphosis and 4 (16.7%) recovered to lordosis. Among 31 segments that showed preoperative lordosis, 19 (61.3%) showed loss of lordosis and 12 (38.7%) showed increased lordosis. Mean range of motion increased significantly after surgery (6.7 to 8.5 degrees, P=0.04). Preoperative and postoperative segmental kyphosis was not related to clinical success. Cervical arthroplasty with the Bryan Cervical Disc prosthesis failed to restore segmental lordotic angle. A concern arises because it is well known that the fusion in kyphotic curvature causes more frequent problems on adjacent levels in anterior cervical discectomy and fusion. For the present, it seems preferable to exclude the patient who already has significant segmental kyphosis from disc arthroplasty with Bryan Cervical Disc prosthesis.     

Design limitations of Bryan disc arthroplasty.

BACKGROUND CONTEXT: Disc arthroplasty is gaining momentum as a surgical procedure in the treatment of spinal degenerative disease. Results must be carefully scrutinized to recognize benefits as well as limitations. PURPOSE: The aim of this study was to investigate factors associated with segmental kyphosis after Bryan disc replacement. STUDY DESIGN/SETTING: Prospective study of a consecutively enrolled cohort of 10 patients treated in a single center using the Bryan cervical disc prosthesis for single-level segmental reconstruction in the surgical treatment of cervical radiculopathy and/or myelopathy. Radiographic and quality of life outcome measures. METHODS: Static and dynamic lateral radiographs were digitally analyzed in patients undergoing Bryan disc arthroplasty throughout a minimum 3-month follow-up period. Observations were compared with preoperative studies looking for predictive factors of postoperative spinal alignment. RESULTS: Postoperative end plate angles through the Bryan disc in the neutral position were kyphotic in 9 of 10 patients. Compared with preoperative end plate angulation there was a mean change of -7 degrees (towards kyphosis) in postoperative end plate alignment (p=.007, 95% confidence interval [CI] -6 degrees to -13 degrees). This correlated significantly with postoperative reduction in posterior vertebral body height of the caudal segment (p=.011, r2=.575) and postoperative functional spine unit (FSU) kyphosis (p=.032, r2=.46). Despite intraoperative distraction, postoperative FSU height was significantly reduced, on average by 1.7 mm (p=.040, 95% CI 0.5-2.8 mm). CONCLUSIONS: Asymmetrical end plate preparation occurs because of suboptimal coordinates to which the milling jig is referenced. Although segmental motion is preserved, Bryan disc arthroplasty demonstrates a propensity towards kyphotic orientation through the prosthesis likely as a result of intraoperative lordotic distraction. FSU angulation tends towards kyphosis and FSU height is decreased in the postoperative state from lack of anterior column support. Limitations of Bryan cervical disc arthroplasty should be carefully considered when reconstruction or maintenance of cervical lordosis is desirable.     

The Bryan cervical disc prosthesis as an alternative to arthrodesis in the treatment of cervical spondylosis: 46 consecutive cases

We present data relating to the Bryan disc arthroplasty for the treatment of cervical spondylosis in 46 patients.Patients with either radiculopathy or myelopathy had a cervical discectomy followed by implantation of a cervical disc prosthesis. Patients were reviewed at six weeks, six months and one year and assessment included three outcome measures, a visual analogue scale (VAS), the short form 36 (SF-36) and the neck disability index (NDI). The results were categorised according to a modification of Odom's criteria. Radiological evaluation, by an independent radiologist, sought evidence of movement, stability and subsidence of the prosthesis.A highly significant difference was found for all three outcome measurements, comparing the pre-operative with the post-operative values: VAS (Z = 6.42, p < 0.0001), SF-36 (mental component) (Z = -5.02, p < 0.0001), SF-36 (physical component) (Z = -5.00, p < 0.0001) and NDI (Z = 7.03, p < 0.0001). The Bryan cervical disc prosthesis seems reliable and safe in the treatment of patients with cervical spondylosis.     

Comparison of radiographic changes after ACDF versus Bryan disc arthroplasty in single and bi-level cases

The object of this study is to compare radiographic outcomes of anterior cervical decompression and fusion (ACDF) versus cervical disc replacement using the Bryan Cervical Disc Prosthesis (Medtronic Sofamor Danek, Memphis, TN) in terms of range of motion (ROM), Functional spinal unit (FSU), overall sagittal alignment (C2–C7), anterior intervertebral height (AIH), posterior intervertebral height (PIH) and radiographic changes at the implanted and adjacent levels. The study consisted of 105 patients. A total of 63 Bryan disc were placed in 51 patients. A single level procedure was performed in 39 patients and a two-level procedure in the other 12. Fifty-four patients underwent ACDF, 26 single level cases and 28 double level cases. The Bryan group had a mean follow-up 19 months (12–38). Mean follow-up for the ACDF group was 20 months (12–40 months). All patients were evaluated using static and dynamic cervical spine radiographs as well as MR imaging. All patients underwent anterior cervical discectomy followed by autogenous bone graft with plate (or implantation of a cage) or the Bryan artificial disc prosthesis. Clinical evaluation included the visual analogue scale (VAS), and neck disability index (NDI). Radiographic evaluation included static and dynamic flexion-extension radiographs using the computer software (Infinitt PiviewSTAR 5051) program. ROM, disc space angle, intervertebral height were measured at the operative site and adjacent levels. FSU and overall sagittal alignment (C2–C7) were also measured pre-operatively, postoperatively and at final follow-up. Radiological change was analyzed using χ ² test (95% confidence interval). Other data were analyzed using the mixed model (SAS enterprises guide 4.1 versions). There was clinical improvement within each group in terms of VAS and NDI scores from pre-op to final follow-up but not significantly between the two groups for both single (VAS p = 0.8371, NDI p = 0.2872) and double (VAS p = 0.2938, NDI p = 0.6753) level surgeries. Overall, ROM and intervertebral height was relatively well maintained during the follow-up in the Bryan group compared to ACDF. Regardless of the number of levels operated on, significant differences were noted for overall ROM of the cervical spine (p < 0.0001) and all other levels except at the upper adjacent level for single level surgeries (p = 0.2872). Statistically significant (p < 0.0001 and p = 0.0172) differences in the trend of intervertebral height measurements between the two groups were noted at all levels except for the AIH of single level surgeries at the upper (p = 0.1264) and lower (p = 0.7598) adjacent levels as well as PIH for double level surgeries at the upper (p = 0.8363) adjacent level. Radiological change was 3.5 times more observed for the ACDF group. Clinical status of both groups, regardless of the number of levels, showed improvement. Although clinical outcomes between the two groups were not significantly different at final follow-up, radiographic parameters, namely ROM and intervertebral heights at the operated site, some adjacent levels as well as FSU and overall sagittal alignment of the cervical spine were relatively well maintained in Bryan group compared to ACDF group. We surmise that to a certain degree, the maintenance of these parameters could contribute to reduce development of adjacent level change. Noteworthy is that radiographic change was 3.5 times more observed for ACDF surgeries. A longer period of evaluation is needed, to see if all these radiographic changes will translate to symptomatic adjacent level disease.     

人工椎间盘置换术治疗跳跃型多节段颈椎病的中期疗效

 目的 评价 Bryan 人工间盘置换术治疗跳跃型多节段颈椎病的疗效。方法 回顾性分析 2002 年 2 月至 2012 年 5 月接受 Bryan 间盘置换术（Bryan 组）或颈前路减压植骨融合术（ACDF 组）治疗的跳跃型多节段颈椎病患者相关资料。临床功能评估采用日本矫形外科协会（Japanese orthopaedic association,JOA）评分、颈椎功能障碍指数（neck disability index,NDI）、疼痛视觉模拟评分（visual analoguc scale,VAS）,影像学评估采用颈椎矢状位曲度、颈椎整体活动度及中间节段活动度,并于末次随访时评估邻近节段退变情况。结果 49 例患者随访超过 24 个月,Bryan 组 18 例,ACDF 组 31 例。两组患者性别、年龄、疾病类型等人口学资料的差异无统计学意义。两组患者术后 JOA、NDI、VAS 评分均较术前有明显改善。两组间各时间节点比较仅末次随访时 VAS 评分的差异有统计学意义。Bryan 组术后轴性症状发生率、颈椎活动度和未手术节段活动度分别为 11.1%、35.5°±5.9°和 7.3°±1.4°,ACDF 组分别为 45.2%、24.5°±6.2°、10.1°±1.6°,差异均有统计学意义。Bryan 组患者邻近节段无明显退变,ACDF 组 2 例出现退变,但无需再次手术。结论 应用 Bryan 间盘置换术治疗跳跃型多节段颈椎病,可有效改善神经功能,保留颈椎整体活动度,减少未手术节段活动度的代偿性增加,从而降低邻近节段退变及轴性症状发生率。     

人工颈椎间盘置换术在后纵韧带骨化症中的应用

[目的]观察应用Bryan颈椎间盘假体置换术治疗后纵韧带骨化症的近期效果。[方法]2005年10月～2007年6月应用Bryan人工颈椎间盘假体置换术治疗局限型后纵韧带骨化症患者15例,术前和术后6个月时进行JOA评分,并摄颈椎前屈后伸位X线片,观察假体稳定性及颈椎置换节段的活动度。[结果]患者术后症状均明显缓解,随访6～24个月,JOA评分由术前平均8.5分上升至术后平均15.8分。置换节段保留了运动功能,假体稳定无移位。[结论]人工颈椎间盘置换术近期可保持前路减压的良好效果,同时可获得术后即刻稳定性。维持颈椎近正常的活动度。人工颈椎间盘置换术是治疗局限型后纵韧带骨化症的一种有效方法。     

Clinical and radiological analysis of Bryan cervical disc arthroplasty: eight-year follow-up results compared with anterior cervical discectomy and fusion

Purpose

Bryan cervical disc arthroplasty has been reported with satisfactory short- and medium-term clinical results. However, the long-term clinical and radiographic outcomes are seldom reported. The purpose of this study was to compare the eight-year follow-up results in patients who underwent Bryan disc arthroplasty with patients received ACDF, and assess the incidence of heterotopic ossification (HO) and its effect on clinical outcome and mobility of the device.

Methods

Thirty-one patients underwent Bryan disc arthroplasty, and 35 patients underwent ACDF were included in the study. The Japanese Orthopedic Association (JOA) scores, neck disability index (NDI), visual analogue scale (VAS) of neck and arm pain, and the radiographs were used to evaluate the outcomes. The heterotopic ossification (HO) was determined by CT scan and was classified into three subgroups to compare the related effect. Adjacent segment degeneration (ASD) was also observed.

Results

At final follow-up, there were no significant differences in JOA scores between two groups, but the improvement in NDI and neck or arm VAS were significantly greater in the Bryan disc cohort. The range of motion at the index level was 7.0° in Bryan group, while 100 % bone fusion were achieved in ACDF group. HO was observed in 18 (51.4 %) levels. There were more restricted movement of the prosthesis and slight higher rate of axial pain in patients with severe-HO (grade III and IV). Fourteen (28.6 %) levels developed ASD in Bryan group, which was significantly lower than that (58.6 %) in ACDF group.

Conclusions

At eight year follow-up, the clinical and radiographic outcomes of Bryan cervical disc arthroplasty compared favorably to those of ACDF. It avoided accelerated adjacent segment degeneration by preserving motion. However, severe HO restricted the ROM of the index levels and maybe associated with post-operative axial pain.

     

Effects of anterior contralateral cervical microdiskectomy on radiological and clinical outcome

BACKGROUND: We have conducted a prospective study to investigate the relationship between cervical spine alignment and clinical outcome in 102 patients undergoing anterior contralateral microdiskectomy without interbody graft or cage. METHODS: Preoperative and postoperative lateral cervical radiographs were obtained, and curvature of the surgically treated spinal segments and the overall curvature of the cervical spine were evaluated in all patients. Clinical outcomes were assessed using the NDI and SF-36. RESULTS: There was no significant change in the mean overall cervical curvature (C2-C7) angles postoperatively in late follow-up findings (P = .72). It represented a statistically significant mean loss of 2.73 degrees of segmental lordosis (P < .0001). The NDI scores decreased significantly in both early and late follow-up evaluations, and the SF-36 scores demonstrated significant improvement in late follow-up results in our series. Analysis of clinical outcome showed no statistical differences between patients with segmental lordosis or kyphosis. CONCLUSION: Despite the kyphosis seen at the treated levels, the overall alignment between C2 and C7 did not change significantly, indicating that the untreated segments of the cervical spine were compensating for focal kyphosis.     

Segmental malalignment with the Bryan Cervical Disc prosthesis--does it occur?

The early clinical results with the Bryan Cervical Disc prosthesis are encouraging but 2 recent small published series have noted postoperative radiologic kyphosis of the functional spinal unit (FSU) of 4 and 6 degrees. The current study was undertaken to accurately assess the extent of any sagittal deformity after the use of this prosthesis in a substantial, multisurgeon case series. The neutral, erect x-rays of 67 consecutive patients (88 disc levels) operated by one of 3 surgeons, were examined using manual and digital image analysis techniques for FSU sagittal angulation (lordosis), prosthesis shell angulation, segmental olisthesis, and overall cervical alignment. Measurement accuracy was confirmed using interobserver and intraobserver studies. There was a median loss of 2 degrees in FSU lordosis when compared with preoperative imaging (P<0.0001, range: 8-degree loss to 5-degree gain). A median 2 degrees of prosthesis shell kyphosis also occurred (range: 15-degree kyphosis to 12-degree lordosis) but shell angulation correlated weakly with the change in FSU lordosis (rs=0.37, P=0.001). There was a significant difference in the median loss of FSU lordosis between surgeon 1 and surgeons 2 and 3 (3.5 degrees vs. 2 degrees, P=0.005). Median olisthesis of the prosthesis shells was -0.1 mm (range: +1.5 to -2.5 mm). Median postoperative overall cervical lordosis reduced by 4 degrees (P<0.004). A small loss in median FSU lordosis was observed after insertion of the Bryan disc. The observed changes were generally small but varied among both the patients and the surgeons, suggesting that variables may exist which contribute to postoperative sagittal alignment. These are the subject of an accompanying study.     

Long-term kinematic analysis of cervical spine after single-level implantation of Bryan cervical disc prosthesis

Background contextCervical arthroplasty theoretically reduces the risk of adjacent level disc degeneration and segmental instability that may be seen after a cervical fusion. An essential argument in confirming the utility of cervical arthroplasty is long-term confirmation that cervical disc replacements can maintain physiological kinematics at the index and adjacent levels.PurposeThe purpose of this in vivo prospective study was to characterize the long-term segmental kinematic outcomes after cervical arthroplasty.Study design/settingProspective cohort study.Patient sampleTwenty patients with a 5-year clinical follow-up who underwent anterior cervical discectomy with insertion of the Bryan cervical disc.Outcome measuresPhysiological measures (kinematic analysis of lateral neutral, flexion, and extension radiographic imaging).MethodsTwenty consecutive patients with degenerative disc disease were followed with regular radiographic imaging after implantation of the Bryan cervical disc prosthesis. Lateral neutral, flexion, and extension radiographs (n=240) were analyzed using Quantitative Motion Analysis software (Medical Metrics, Inc., Houston, TX, USA) to measure the biomechanical profile at the index level and adjacent levels up to 5 years after surgery. Parameters collected included range of motion (ROM), functional spinal unit (FSU) angle, anterior and posterior disc heights, sagittal translation, and center of rotation (COR).ResultsBiomechanics of the implanted artificial cervical disc was maintained up to 5 years with no significant changes in ROM, FSU angle, disc height, sagittal translation, and COR values when compared with early postoperative performance. Artificial discs were able to adequately restore and maintain preoperative kinematics. Early differences seen in disc height and FSU angle did not change during the duration of follow-up. No significant kyphotic changes or decrease in ROM were seen at the adjacent spinal levels.ConclusionsThe Bryan cervical disc prosthesis provides for a durable solution for functional spinal motion at the operated level and maintained the preoperative kinematics at adjacent levels at the 5-year follow-up.     

Bryan颈椎间盘置换在治疗颈椎病中对颈椎曲度和置换节段的影响

目的:探讨Bryan颈椎间盘置换在治疗颈椎病中对颈椎曲度和置换节段的影响,并分析其临床疗效。方法:对2010年8月至2013年8月行Bryan人工颈椎间盘假体植入的49例患者进行回顾性分析,男26例,女23例;平均年龄48.5岁;神经根型21例,脊髓型16例,混合型12例;单节段置换21例,双节段置换28例。采用视觉疼痛模拟评分(visual analogue scale,VAS)比较手术前后的疼痛情况;根据日本骨科协会评估治疗分数(Japanese Orthopaedic Association Scores,JOA)和颈椎功能障碍指数(Neck Disability Index,NDI)评估神经功能改善状况;通过颈椎正侧屈伸位X线测量分析手术前后颈椎生理前凸曲度,脊柱功能单位(functional spinal unit,FSU)曲度,置换及邻近节段活动度,FSU活动度变化;采用Odom法进行疗效评定。结果:所有患者获得随访,时间18.5~37.3个月,平均33.1个月。VAS、JOA、NDI评分术前分别为7.08±1.55、5.2±1.9、39.96±7.06,术后3个月分别为3.76±2.33、13.2±1.2、25.20±6.64,末次随访分别为2.80±1.50、14.3±1.6、24.24±7.89,术后3个月和末次随访较术前明显改善(P0.05),末次随访和术后3个月比较差异无统计学意义。颈椎生理前凸曲度由术前的(10.64±4.26)°增加至末次随访时的(13.68±4.56)°,FSU曲度由术前的(5.40±0.41)°增加至末次随访时的(9.92±2.00)°(P0.05)。术前、术后3个月、末次随访颈椎活动度为(70.84±6.17)°、(60.00±6.58)°、(71.48±4.61)°,FSU活动度为(12.00±0.49)°、(9.36±0.26)°、(12.52±0.33)°,置换节段活动度为(10.48±0.67)°、(7.24±0.34)°、(9.28±0.36)°,置换上位节段活动度为(10.52±0.60)°、(8.60±0.30)°、(10.44±0.43)°,置换下位节段活动度为(8.48±0.40)°、(6.56±0.36)°、(9.60±0.39)°,术后3个月与术前比较差异均有统计学意义(P0.05),末次随访与术前比较差异均无统计学意义(P0.05)。术后发生咽部不适、声音嘶哑5例,均于术后2周内恢复正常。术后6个月发现异位骨化1例,术后12个月发现假体移位1例。按照Odom评定标准,优20例,良27例,一般2例。结论 :Bryan人工颈椎间盘置换术不仅有良好临床疗效,同时重建了颈椎和FSU前凸曲度,保留了颈椎置换节段活动度,恢复了颈椎整体生物力学功能。     

Clinical and radiographic results of Bryan cervical total disc replacement: 4-year outcomes in a prospective study

Introduction

Early results have indicated that the Bryan cervical total disc replacement (TDR) favorably compares to anterior cervical decompression and fusion, while it is associated with fewer complications and higher levels of satisfaction. In this study, we sought to prospectively report the midterm outcomes of the Bryan TDR.

Patients and methods

A total of 20 patients had performed their 4-year follow-up visit and had been assessed clinically and radiologically. Clinical outcomes (JOA, VAS, NDI, SF-36) and ROM measurements were investigated preoperatively and at 1 and 6 months, and 1, 2 and 4 years after operation. Complications were also investigated. Occurrences of heterotopic ossifications (HOs) and adjacent-level degeneration (ALD) radiographic changes were detected from 4-year follow-up X-rays.

Results

The mean JOA score, VAS score for arm and neck, NDI score and SF-36 score for PCS and MCS were reduced significantly at each postoperative time point when compared with the preoperative condition. The range of movement of the cervical spine, functional spinal unit, treated segment and the adjacent segment temporarily decreased at the early assessment, but all recovered to preoperative levels over a 6-month to 4-year time period. HO was evident in 6 of the 23 operated segments, which did not restrict the movement of the prosthesis. No obvious ALD was found on MRI. There were no cases of prosthesis migration, subsidence, loosening or wear.

Conclusion

The midterm outcomes demonstrated that the Bryan TDR maintains favorable clinical and radiological results, with preservation of movement and satisfactory clinical outcome. There were no serious complications or cases of prosthetic wear or failure. The long-term benefits are yet to be examined.     

Fusion versus Bryan Cervical Disc in two-level cervical disc disease: a prospective,randomised study

In this prospective study, our aim was to compare the functional results and radiographic outcomes of fusion and Bryan Cervical Disc replacement in the treatment of two-level cervical disc disease. A total of 65 patients with two-level cervical disc disease were randomly assigned to two groups, those operated on with Bryan Cervical Disc replacement (31) and those operated on with anterior cervical fusion with an iliac crest autograft and plate (34). Clinical evaluation was carried out using the visual analogue scale (VAS), the Short Form 36 (SF-36) and the neck disability index (NDI) during a two year follow-up. Radiological evaluation sought evidence of range of motion, stability and subsidence of the prosthesis. Substantial reduction in NDI scores occurred in both groups, with greater percent improvement in the Bryan group (P = 0.023). The arm pain VAS score improvement was substantial in both groups. Bryan artificial cervical disc replacement seems reliable and safe in the treatment of patients with two-level cervical disc disease.     

Long-term clinical and radiological outcomes of anterior uncoforaminotomy for unilateral single-level cervical radiculopathy: retrospective cohort study

BACKGROUND CONTEXTAnterior cervical discectomy and fusion is a common procedure for degenerative cervical radiculopathy. In 1996, Dr. H.D. Jho reported an operative technique allowing nerve root decompression via anterior uncoforaminotomy whereas avoiding fusion.PURPOSETo assess long-term clinical and radiological outcomes of anterior uncoforaminotomy in patients with degenerative cervical spine pathology.STUDY DESIGNA single clinic, retrospective cohort study.PATIENT SAMPLEAdult patients who underwent anterior uncoforaminotomy from 2013 to 2018.OUTCOME MEASURESClinical outcomes were assessed using VAS, NDI, SF-36 criteria. Radiological parameters included sagittal balance, disc height and White anPanjabi criterion.MATERIALS AND METHODSAll patients underwent unilateral single-level anterior uncoforaminotomy, and long-term clinical and radiologic follow up was carried out. Clinical outcomes were assessed using VAS, NDI, SF-36 criteria. Radiological parameters evaluated included sagittal balance, disc height and White and Panjabi criteria (3.5 mm of translation, 11 degrees of kyphosis). The mean follow-up period was 33.3 ± 10.6 months (range 12–57 months).RESULTSAll measures of clinical outcome improved. VAS (neck) and VAS (arm) decreased 3 [2; 4] and 5 [3; 5.2] points (median [interquartile range]), respectively (p<0.001); NDI improved from 0.38 [0.36; 0.4], to 0.29 [0.22; 0.34] (p<0.001). Two patients (6%) required additional surgery one year after operation. There were no complications in the perioperative period. Disc height decreased 0.8 mm [0.1; 2.1] (p<0.001). All patients retained stability of the cervical spine based on White and Panjabi criteria. Sagittal balance parameters did not change significantly.CONCLUSIONUncoforaminotomy is an effective and safe method to decompress a unilateral single-level nerve root in degenerative cervical radiculopathy whereas preserving anatomy and motion of the cervical spine.     

Cervical kinematics and radiological changes after Discover artificial disc replacement versus fusion

Background contextThe cervical disc arthroplasty has emerged as a promising alternative to the anterior cervical discectomy and fusion (ACDF) in patients with radiculopathy or myelopathy with disc degeneration disease. The advantages of this technique have been reported to preserve the cervical mobility and possibly reduce the adjacent segment degeneration. However, no studies have compared the clinical outcomes and radiological results in patients treated with Discover artificial disc replacement to those observed in matched group of patients that have undergone ACDF.PurposeWe conducted this clinical study to compare the cervical kinematics and radiographic adjacent-level changes after Discover artificial disc replacement with ACDF.Study designAnalysis and evaluation of data acquired in a comparative clinical study.Patient sampleThe number of patients in the Discover and ACDF group were 149 and 196, respectively.Outcome measuresThe Neck Disability Index (NDI) and visual analog scale (VAS) pain score were evaluated. The range of movement (ROM) by the shell angle, the functional segment unit and global angles were measured, and the postoperative radiological changes at adjacents levels were observed.MethodsA total of 149 patients with symptomatic single or two-level cervical degenerative diseases received the Discover cervical artificial disc replacement from November 2008 to February 2010. During the same period, there were a total of 196 patients undergoing one or two-level ACDF. The average follow-up periods of the Discover disc group and ACDF group were 22.1 months and 22.5 months, respectively. Before surgery, patients were evaluated using static and dynamic cervical spine radiographs in addition to computerized tomography and magnetic resonance imaging. Static and dynamic cervical spine radiographs were obtained after surgery and then at 3- and 6-month follow-up. Then, the subsequent follow-up examinations were performed at every 6-month interval. The clinical results in terms of NDI and VAS scores, the parameters of cervical kinematics, postoperative radiological changes at adjacent levels, and complications in the two groups were statistically analyzed and compared. No funding was received for this study, and the authors report no potential conflict of interest–associated biases in the text.ResultsAlthough the clinical improvements in terms of NDI and VAS scores were achieved in both the Discover and ACDF group, no significant difference was found between the two groups for both single- (VAS p=.13, NDI p=.49) and double-level surgeries (VAS p=.28, NDI p=.21). Significant differences of cervcial kinematics occurred between the Discover and the ACDF group for both the single- and double-level surgeries at the operative segments (p<.001). Except the upper adjacent levels for the single-level Discover and ACDF groups (p=.33), significant increases in adjacent segment motion were observed in the ACDF group compared with the minimal ROM changes in adjacent segment motion noted in the Discover group, and the differences between the two groups for both single and double-level procedures were statistically significant (p<.05). There were significant differences in the postoperative radiological changes at adjacent levels between the Discover and ACDF groups for the single-level surgery (p<.001, χ²=18.18) and the double-level surgery (p=.007, χ²=7.2). No significant difference of complications was found between the Discover and ACDF groups in both single (p=.25, χ²=1.32) and double-level cases (p=.4, χ²=0.69).ConclusionsThe adjacent segment ROM and the incidence of radiographic adjacent-level changes in patients undergoing ACDF were higher than those undergoing Discover artificial disc replacement. The cervical mobility was relatively well maintained in the Discover group compared with the ACDF group, and the Discover cervical disc arthroplasty can be an effective alternative to the fusion technique.     

The sagittal profile of the cervical and lumbosacral spine in Scheuermann thoracic kyphosis

The sagittal profiles of the cervical and lumbar spine have not been studied in Scheuermann kyphosis. The purpose of this study was to investigate these profiles. Standing lateral radiographs of the spine in 34 children with Scheuermann kyphosis were reviewed. Cervical lordosis, lumbar lordosis, thoracic kyphosis, sagittal vertebral axis, and sacral inclination were measured. The relations between these variables were explored using the Pearson correlation. The average patient age was 15.5 +/- 1.8 years, thoracic kyphosis was 65 degrees +/- 12 degrees, lumbar lordosis 71 degrees +/- 13 degrees, and cervical lordosis 4 degrees +/- 15 degrees (Cobb angle), and 9 degrees +/- 14 degrees (posterior vertebral body angle [PVBA]). No correlations were noted between cervical lordosis and thoracic kyphosis. Correlations were noted between cervical lordosis and lumbar lordosis (r2 = 0.17, Cobb angle; r2 = 0.16, PVBA) and between cervical lordosis and the residual sagittal difference (thoracic kyphosis minus lumbar lordosis; r2 = 0.32, p = 0.001 [Cobb angle], and r2 = 0.19, p = 0.01 [PVBA]). In Scheuermann kyphosis, the flexible cervical and lumbar spine is linked by the intermediate rigid thoracic segment. As the residual sagittal difference becomes more kyphotic, lordosis of the cervical spine increases as the patient strives to maintain a forward visual gaze.     

Bryan颈椎人工椎间盘置换术后5年随访结果

目的:观察Bryan颈椎人工椎间盘置换术后5年随访结果。方法:我院从2003年12月开展Bryan颈椎人工椎间盘置换术,术后达到5年的患者共70例,其中57例获得57～69个月(平均60个月)随访。单节段置换47例,双节段置换9例,3节段置换1例。C3/4 5例、C4/5 10例、C5/6 45例、C6/7 8例。术前和末次随访时进行mJOA、VAS、NDI评分,末次随访时进行Odom′s分级评估临床疗效;术前和末次随访时,在过伸过屈侧位X线片上测量置换节段活动度,在侧位X线片上采用McAfee异位骨化分级方法评定异位骨化情况,在MRIT2加权像上采用Miyazaki颈椎间盘退变分级方法评定相邻节段椎间盘退变情况,在MRI中矢状位T2加权像上测量相邻节段突出椎间盘对椎管的侵占率。结果:(1)mJOA评分术前为13.4±1.9分,末次随访时16.1±1.1分,平均改善率为75.0%;上肢痛VAS评分术前为3.3±1.9分,末次随访时0.9±1.2分;颈肩痛VAS评分术前为3.0±1.5分,末次随访时1.6±1.4分;NDI评分术前为14.8±8.6分,末次随访时5.7±4.2分;以上指标末次随访时与术前比较均有统计学差异(P<0.05)。末次随访时Odom′s分级优21例,良27例,可7例,差2例。(2)28例患者获得X线随访,术前置换节段活动度为6.9°±3.0°,末次随访时为7.2°±3.7°,无统计学差异(P>0.05);末次随访时,30个手术节段中12个(40%)出现异位骨化,其中3个(10%)节段丧失活动度。(3)25例患者获得MRI随访,末次随访时50个相邻节段中7个(14%)椎间盘退变分级加重1级,但无相关临床症状出现;相邻节段突出椎间盘对椎管侵占率的年度平均增幅为0.3%～0.5%。结论:Bryan颈椎人工椎间盘置换术后平均5年随访的临床和影像学结果满意,手术节段活动度得到较好保留,相邻节段退变发生率较低,无相邻节段疾病发生。