Screw Motion Used in Semiconstrained Rotational Plate Systems for Anterior Cervical Discectomy and Fusion.

IF 1.6 4区医学 Q3 CLINICAL NEUROLOGY

Clinical Spine Surgery Pub Date : 2025-03-01 Epub Date: 2024-07-25 DOI:10.1097/BSD.0000000000001665

Yasunori Tatara, Takanori Niimura, Akira Sakaguchi, Hiroki Katayama, Yoshinari Miyaoka, Hisanori Mihara

{"title":"Screw Motion Used in Semiconstrained Rotational Plate Systems for Anterior Cervical Discectomy and Fusion.","authors":"Yasunori Tatara, Takanori Niimura, Akira Sakaguchi, Hiroki Katayama, Yoshinari Miyaoka, Hisanori Mihara","doi":"10.1097/BSD.0000000000001665","DOIUrl":null,"url":null,"abstract":"Study design: Retrospective observational study.Objective: To scrutinize screw motion used in semiconstrained rotational plate systems for anterior cervical discectomy and fusion (ACDF).Summary of background data: Semiconstrained rotational plate systems are supposed to control graft subsidence and facilitate lordosis acquisition and maintenance by toggling the instrumented vertebrae via variable-angle screws. However, their benefits may be unrealized if the screws move within the vertebrae.Methods: We reviewed medical records of 119 patients who underwent 1-level, 2-level, 3-level, or 4-level ACDF, divided them into the short-segment (n=62, 1-level or 2-level ACDF) and long-segment (n=59, 3- level or 4-level ACDF) groups, and investigated their immediate and 1-year postoperative lateral radiographs. We measured the fused segmental angle, screw angles at the upper-instrumented vertebra (UIV) and lower-instrumented vertebra (LIV), distance from the screw base to the endplate of UIV/LIV (SBE), and distance from the screw tip to the endplate of UIV/LIV (STE) to analyze the screw motion used in these plate systems. The differences between the immediate and 1-year postoperative values were statistically analyzed. The nonunion level was also investigated.Results: Screw angle and SBE at the LIV significantly decreased in the long-segment group (-14.5±9.8 degrees and -2.8±1.8 mm, respectively) compared with those in the short-segment group (-4.6±6.0 degrees and -1.0±1.5 mm, respectively). Thus, the long-segment group could not maintain the immediate-postoperative segmental angle. Overall, 27 patients developed nonunion, with 19 (70.4%) in the long-segment group and 21 (77.8%) at the lowest fused level.Conclusions: Semiconstrained rotational plate systems provide only vertical forces to the fused segment rather than toggling the instrumented vertebrae. Postoperatively in multilevel ACDF, LIV screws migrate caudally, suggesting that these plate systems are not always effective in maintaining lordosis. Moreover, LIV screws and the anterior wall of the LIV are subject to overloading, resulting in a high rate of nonunion at the lowest fused level.Level of evidence: Level III.","PeriodicalId":10457,"journal":{"name":"Clinical Spine Surgery","volume":" ","pages":"58-63"},"PeriodicalIF":1.6000,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Clinical Spine Surgery","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1097/BSD.0000000000001665","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/7/25 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"CLINICAL NEUROLOGY","Score":null,"Total":0}

引用次数: 0

Abstract

Study design: Retrospective observational study.

Objective: To scrutinize screw motion used in semiconstrained rotational plate systems for anterior cervical discectomy and fusion (ACDF).

Summary of background data: Semiconstrained rotational plate systems are supposed to control graft subsidence and facilitate lordosis acquisition and maintenance by toggling the instrumented vertebrae via variable-angle screws. However, their benefits may be unrealized if the screws move within the vertebrae.

Methods: We reviewed medical records of 119 patients who underwent 1-level, 2-level, 3-level, or 4-level ACDF, divided them into the short-segment (n=62, 1-level or 2-level ACDF) and long-segment (n=59, 3- level or 4-level ACDF) groups, and investigated their immediate and 1-year postoperative lateral radiographs. We measured the fused segmental angle, screw angles at the upper-instrumented vertebra (UIV) and lower-instrumented vertebra (LIV), distance from the screw base to the endplate of UIV/LIV (SBE), and distance from the screw tip to the endplate of UIV/LIV (STE) to analyze the screw motion used in these plate systems. The differences between the immediate and 1-year postoperative values were statistically analyzed. The nonunion level was also investigated.

Results: Screw angle and SBE at the LIV significantly decreased in the long-segment group (-14.5±9.8 degrees and -2.8±1.8 mm, respectively) compared with those in the short-segment group (-4.6±6.0 degrees and -1.0±1.5 mm, respectively). Thus, the long-segment group could not maintain the immediate-postoperative segmental angle. Overall, 27 patients developed nonunion, with 19 (70.4%) in the long-segment group and 21 (77.8%) at the lowest fused level.

Conclusions: Semiconstrained rotational plate systems provide only vertical forces to the fused segment rather than toggling the instrumented vertebrae. Postoperatively in multilevel ACDF, LIV screws migrate caudally, suggesting that these plate systems are not always effective in maintaining lordosis. Moreover, LIV screws and the anterior wall of the LIV are subject to overloading, resulting in a high rate of nonunion at the lowest fused level.

Level of evidence: Level III.

查看原文本刊更多论文

用于颈椎前路椎间盘切除术和融合术的半约束旋转钢板系统中的螺钉运动。

研究设计回顾性观察研究：仔细研究用于颈椎前路椎间盘切除与融合术（ACDF）的半约束旋转钢板系统中使用的螺钉运动：半约束旋转钢板系统应能控制移植物下沉，并通过可变角度螺钉拨动器械椎体促进前凸的获得和维持。然而，如果螺钉在椎体内移动，其优点可能无法实现：我们回顾了119例接受1级、2级、3级或4级ACDF手术的患者的病历，将其分为短节段（62例，1级或2级ACDF）和长节段（59例，3级或4级ACDF）两组，并调查了他们术后即刻和1年的侧位X光片。我们测量了融合节段角度、上器械椎体（UIV）和下器械椎体（LIV）的螺钉角度、螺钉基部到UIV/LIV终板的距离（SBE）以及螺钉顶端到UIV/LIV终板的距离（STE），以分析这些钢板系统中使用的螺钉运动。对术后即刻值和术后一年值之间的差异进行了统计分析。此外，还对未愈合水平进行了调查：结果：与短节段组（分别为-4.6±6.0度和-1.0±1.5毫米）相比，长节段组的螺钉角度和LIV处的SBE明显下降（分别为-14.5±9.8度和-2.8±1.8毫米）。因此，长节段组无法保持术后即刻的节段角度。总体而言，有27名患者出现了骨不连，其中长节段组有19人（70.4%），最低融合水平有21人（77.8%）：结论：半约束旋转接骨板系统只对融合节段提供垂直力，而不是拨动器械椎体。多水平 ACDF 术后，LIV 螺钉会向尾部移位，这表明这些钢板系统并不总是能有效地维持前凸。此外，LIV螺钉和LIV前壁受力过大，导致最低融合水平的不愈合率较高：证据等级：三级。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Clinical Spine Surgery Medicine-Surgery

CiteScore

3.00

自引率

5.30%

发文量

236

期刊介绍： Clinical Spine Surgery is the ideal journal for the busy practicing spine surgeon or trainee, as it is the only journal necessary to keep up to date with new clinical research and surgical techniques. Readers get to watch leaders in the field debate controversial topics in a new controversies section, and gain access to evidence-based reviews of important pathologies in the systematic reviews section. The journal features a surgical technique complete with a video, and a tips and tricks section that allows surgeons to review the important steps prior to a complex procedure. Clinical Spine Surgery provides readers with primary research studies, specifically level 1, 2 and 3 studies, ensuring that articles that may actually change a surgeon’s practice will be read and published. Each issue includes a brief article that will help a surgeon better understand the business of healthcare, as well as an article that will help a surgeon understand how to interpret increasingly complex research methodology. Clinical Spine Surgery is your single source for up-to-date, evidence-based recommendations for spine care.