预弯钛网在单节段颈前路椎体次全切除减压融合术中的应用

目的 :评估预弯钛网在颈前路椎体次全切除减压融合术(anterior cervical corpectomy and fusion,ACCF)治疗脊髓型颈椎病中的实用性和有效性。方法:回顾性分析2016年1月～2017年1月间因脊髓型颈椎病在我科接受单节段ACCF的82例患者的病例资料,其中39例术中放置预弯钛网(预弯钛网组),43例术中放置普通直钛网(直钛网组)。对比两组患者随访期间钛网末端与椎体上终板和下终板贴合度的变化、椎体间高度变化、钛网沉降率、植骨融合率、日本骨科学会(Japanese Orthopedics Association,JOA)评分及颈项部疼痛视觉模拟评分(visual analog scale,VAS)变化情况。结果:预弯钛网组和直钛网组平均随访17.7±2.1个月和18.4±2.4个月。末次随访时,尽管两组间植骨融合率均为100%,但预弯组钛网末端与椎体上终板和下终板角度的变化(1.0°±0.7°,1.1°±0.6°)均低于直钛网组(1.9°±0.4°,2.2°±0.8°),且差异具有显著性(P0.05);预弯钛网组椎间前、后高度的丢失和钛网下沉率分别为-1.9±1.7mm、-1.5±1.6mm及28.2%,而直钛网组分别为-2.8±1.4mm、-2.7±2.2mm及53.4%,预弯钛网组均低于直钛网组且差异均具有统计学意义(P0.05)。末次随访时两组的JOA评分较术前均显著增加,但两组间的JOA评分、神经功能改善率均无明显统计学差异(P0.05);末次随访时两组颈项部VAS评分较术前均显著降低,且预弯钛网组(2.5±1.2分)显著低于直钛网组(3.2±0.8分),组间比较具有统计学意义(P0.05)。结论:在单节段ACCF手术中,预弯钛网能够与邻近椎体上下终板达到较好的贴合度,减少钛网沉降率。     

Subsidence and Nonunion after Anterior Cervical Interbody Fusion Using a Stand-Alone Polyetheretherketone (PEEK) Cage

Background

The purposes of the present study are to evaluate the subsidence and nonunion that occurred after anterior cervical discectomy and fusion using a stand-alone intervertebral cage and to analyze the risk factors for the complications.

Methods

Thirty-eight patients (47 segments) who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage and an autologous cancellous iliac bone graft from June 2003 to August 2008 were enrolled in this study. The anterior and posterior segmental heights and the distance from the anterior edge of the upper vertebra to the anterior margin of the cage were measured on the plain radiographs. Subsidence was defined as ≥ a 2 mm (minor) or 3 mm (major) decrease of the segmental height at the final follow-up compared to that measured at the immediate postoperative period. Nonunion was evaluated according to the instability being ≥ 2 mm in the interspinous distance on the flexion-extension lateral radiographs.

Results

The anterior and posterior segmental heights decreased from the immediate postoperative period to the final follow-up at 1.33 ± 1.46 mm and 0.81 ± 1.27 mm, respectively. Subsidence ≥ 2 mm and 3 mm were observed in 12 segments (25.5%) and 7 segments (14.9%), respectively. Among the expected risk factors for subsidence, a smaller anteroposterior (AP) diameter (14 mm vs. 12 mm) of cages (p = 0.034; odds ratio [OR], 0.017) and larger intraoperative distraction (p = 0.041; OR, 3.988) had a significantly higher risk of subsidence. Intervertebral nonunion was observed in 7 segments (7/47, 14.9%). Compared with the union group, the nonunion group had a significantly higher ratio of two-level fusion to one-level fusions (p = 0.001).

Conclusions

Anterior cervical fusion using a stand-alone cage with a large AP diameter while preventing anterior intraoperative over-distraction will be helpful to prevent the subsidence of cages. Two-level cervical fusion might require more careful attention for avoiding nonunion.     

Subsidence of Cylindrical Cage (AMSLU? Cage) : Postoperative 1 Year Follow-up of the Cervical Anterior Interbody Fusion

Objective

There are numerous reports on the primary stabilizing effects of the different cervical cages for cervical radiculopathy. But, little is known about the subsidence which may be clinical problem postoperatively. The goal of this study is to evaluate subsidence of cage and investigate the correlation between radiologic subsidence and clinical outcome.

Methods

To assess possible subsidence, the authors investigated clinical and radiological results of the one-hundred patients who underwent anterior cervical fusion by using AMSLU™ cage during the period between January 2003 and June 2005. Preoperative and postoperative lateral radiographs were measured for height of intervertebral disc space where cages were placed. Intervertebral disc space was measured by dividing the sum of anterior, posterior, and midpoint interbody distance by 3. Follow-up time was 6 to 12 months. Subsidence was defined as any change in at least one of our parameters of at least 3 mm.

Results

Subsidence was found in 22 patients (22%). The mean value of subsidence was 2.21 mm, and mean subsidence rate was 22%. There were no cases of the clinical status deterioration during the follow-up period. No posterior or anterior migration was observed.

Conclusion

The phenomenon of subsidence is seen in substantial number of patients. Nevertheless, clinical and radiological results of the surgery were favorable. An excessive subsidence may result in hardware failure. Endplate preservation may enables us to control subsidence and reduce the number of complications.     

双节段颈椎前路椎体次全切除融合术后钛笼下沉的探讨

目的：探讨经颈椎前路椎体次全切除钛笼植骨钛板内固定术治疗双节段脊髓型颈椎病术后钛笼下沉的相关影响因素。方法：回顾性分析我院2011年1月至2013年4月收治的86例行颈椎前路椎体次全切除钛笼植骨融合钛板内固定术患者的颈椎正侧位片及临床资料,随访6个月,根据下沉与否分为下沉组和非下沉组进行观察,分析术后钛笼下沉与年龄、性别、手术节段、临床疗效、病变节段撑开角度、和安置位置的相关性。结果：术后6个月时86例患者中有22例发生钛笼下沉（25.6%）,下沉组和非下沉组患者术前平均年龄、性别、手术节段（C5-C7）比较存在统计学差异（P<0.05）,余比较无统计学差异（P>0.05）。两组术后JOA评分均较术前明显改善,存在统计学差异（P<0.05）,两组间比较存在显著统计学差异（P<0.01）。两组融合率比较无明显统计学差异（P>0.05）。撑开角度<30°者共63例,下沉组12例（19.0%）,撑开角度≥30°者共23例,下沉组10例（43.5%）。撑开角度<30°与撑开角度≥30°对于下沉发生率的影响比较有统计学差异（P<0.05）。椎体前缘与钛笼前缘间距<1mm者共66例,下沉组13例（19.7%）,椎体前缘与钛笼前缘间距>1mm者共20例,下沉9例（45.0%）,椎体前缘与钛笼前缘间距>1mm与椎体前缘与钛笼前缘间距<1mm对于下沉发生率的影响比较有统计学差异（P<0.05）。结论：撑开角度和安放位置可能是影响钛笼术后下沉的重要因素,此外年龄、性别、手术节段（C5-C7）、骨密度、BMI对钛笼下沉均有不同程度的影响。     

Cage subsidence does not, but cervical lordosis improvement does affect the long-term results of anterior cervical fusion with stand-alone cage for degenerative cervical disc disease: a retrospective study

Objective

Clinical outcomes of the stand-alone cage have been encouraging when used in anterior cervical discectomy and fusion (ACDF), but concerns remain regarding its complications, especially cage subsidence. This retrospective study was undertaken to investigate the long-term radiological and clinical outcomes of the stand-alone titanium cage and to evaluate the incidence of cage subsidence in relation to the clinical outcome in the surgical treatment of degenerative cervical disc disease.

Methods

A total of 57 consecutive patients (68 levels) who underwent ACDF using a titanium box cage for the treatment of cervical radiculopathy and/or myelopathy were reviewed for the radiological and clinical outcomes. They were followed for at least 5 years. Radiographs were obtained before and after surgery, 3 months postoperatively, and at the final follow-up to determine the presence of fusion and cage subsidence. The Cobb angle of C2–C7 and the vertebral bodies adjacent to the treated disc were measured to evaluate the cervical sagittal alignment and local lordosis. The disc height was measured as well. The clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) score for cervical myelopathy, before and after surgery, and at the final follow-up. The recovery rate of JOA score was also calculated. The Visual Analogue Scale (VAS) score of neck and radicular pain were evaluated as well. The fusion rate was 95.6% (65/68) 3 months after surgery.

Results

Successful bone fusion was achieved in all patients at the final follow-up. Cage subsidence occurred in 13 cages (19.1%) at 3-month follow-up; however, there was no relation between fusion and cage subsidence. Cervical and local lordosis improved after surgery, with the improvement preserved at the final follow-up. The preoperative disc height of both subsidence and non-subsidence patients was similar; however, postoperative posterior disc height (PDH) of subsidence group was significantly greater than of non-subsidence group. Significant improvement of the JOA score was noted immediately after surgery and at the final follow-up. There was no significant difference of the recovery rate of JOA score between subsidence and non-subsidence groups. The recovery rate of JOA score was significantly related to the improvement of the C2–C7 Cobb angle. The VAS score regarding neck and radicular pain was significantly improved after surgery and at the final follow-up. There was no significant difference of the neck and radicular pain between both subsidence and non-subsidence groups.

Conclusions

The results suggest that the clinical and radiological outcomes of the stand-alone titanium box cage for the surgical treatment of one- or two-level degenerative cervical disc disease are satisfactory. Cage subsidence does not exert significant impact upon the long-term clinical outcome although it is common for the stand-alone cages. The cervical lordosis may be more important for the long-term clinical outcome than cage subsidence     

颈前路椎体次全切植骨融合手术术后钛笼塌陷观察及其原因分析

目的探讨颈前路椎体次全切植骨融合手术(Anterior cervical corpectomy and fusion,ACCF)术后钛笼塌陷的发生率以及钛笼塌陷的影响因素。方法回顾性分析我科室收治的42例脊髓型颈椎病及后纵韧带骨化患者ACCF术前、术后及末次随访时节段Cobb角、椎间前缘高度、椎间后缘高度等指标以评价术后手术节段的变化情况。结果术后6月41例患者(97.6%)手术节段达到骨性融合,1例患者术后12月骨性融合。42例患者中11例发生钛笼重度塌陷(26.2%)。其中2例出现颈部疼痛、神经症状复发等情况。末次随访时时,重度钛笼塌陷组在椎间前缘高度及椎间后缘高度低于未塌陷组,节段Cobb角大于未塌陷组。结论 ACCF术后钛笼塌陷率高,且重度钛笼塌陷可引起颈部疼痛、神经症状复发等并发症。术中应注意终板的保护、钛笼的裁减,以一定程度地防止钛笼塌陷的发生。     

Influence of cement penetration and graft density on stem stability in impaction allografting: A finite element study

Background

Excessive stem migration is often problematic after impaction allografting. The mechanisms responsible for migration are not known, but achieving a dense graft bed has traditionally been believed to be essential for stem stability. When the stem is cemented into the allograft bed, however, the graft becomes infiltrated with bone cement. Extensive cement penetration into the graft has been observed in previous studies, resulting in regions of cement–endosteum contact.

Methods

This study explored the effects of graft density and cement penetration on stem motion using a finite element model that was validated against experimental data.

Findings

Cement penetration has a considerable stabilizing effect on stem motion, whereas graft density is important only when there is no cement–endosteum contact. Stem migration can be attributed primarily to slippage at the endosteum and stem–cement interfaces rather than to shear failure within the graft.

Interpretation

Partial cement penetration to the endosteum increases the likelihood of meeting clinical requirements of early implant stability, particularly when a dense graft bed cannot be achieved.     

斜外侧腰椎间融合术后融合器沉降原因的研究进展

目的总结斜外侧腰椎间融合术(OLIF)治疗腰椎退变性疾病患者术后融合器沉降的发生情况及原因。方法以“斜外侧腰椎间融合术”“腰椎间融合术”“融合器”“沉降”“并发症”“椎弓根螺钉”“终板损伤”“骨质疏松”“微创融合术”和“oblique lateral interbody fusion”“interlumbar fusion”“cage”“subsidence”“complications”“pedicle screw”“end plate damage”“osteoporosis”“minimally invasive fusion”为中、英文关键词,在中国知网、万方数据库、SinoMed、PubMed等数据库中检索2020年3月之前发表的OLIF在治疗脊柱退变疾病术后融合器沉降发生情况的相关文献856篇,剔除内容不符、无法获取全文、重复性研究或存在设计缺陷的文献,对最终纳入的30篇文献有关融合器沉降的发生情况和原因进行总结、分析。结果OLIF术后融合器沉降的发生率为4.38%~27.90%。发生融合器沉降的原因主要为缺乏有效的钉棒系统固定、融合器型号选择不佳、各种原因导致的终板损伤、骨质疏松等。结论OLIF术后融合器沉降的发生情况较高,原因较多,如何采取措施预防融合器沉降仍需进一步探讨。