Evidence map›Paper›PMID 33893554›Full record

ArticleEuropean spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society2021

Surgical nuances and construct patterns influence construct stiffness in C1-2 stabilizations: a biomechanical study of C1-2 gapping and advanced C1-2 fixation.

Heiko Koller, Sebastian Hartmann, Gmeiner Raphael, Werner Schmölz, Christoph Orban, Claudius Thome

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In one paragraph

Article in European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
0.2field-weighted citation impact, top 49% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed, 1 citations in OpenAlex.

  1. Cervical scoliosis surgery: understanding neurological complications and defining prevention strategies. A biomechanical study and narrative review.European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society · 2026
    Review
  2. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors at 2 institutions in 2 countries.

Heiko KollerDepartment of Neurosurgery, Technical University of Munich (TUM), Klinikum rechts der Isar, Ismaninger Str. 22, 81675, Munich, Germany. koller-spine@gmx.de.
Sebastian HartmannDepartment of Neurosurgery, Medical University Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria.
Gmeiner RaphaelDepartment of Neurosurgery, Medical University Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria.
Werner SchmölzDepartment of Trauma Surgery, Medical University Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria.
Christoph OrbanDepartment of Trauma Surgery, Medical University Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria.
Claudius ThomeDepartment of Neurosurgery, Medical University Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria.
Innsbruck Medical University · ATParacelsus Medical University · AT

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeStabilization of C1-2 using a Harms-Goel construct with 3.5 mm titanium (Ti) rods has been established as a standard of reference (SOR). A reduction in craniocervical deformities can indicate increased construct stiffness at C1-2. A reduction in C1-2 can result in C1-2 joint gapping. Therefore, the authors sought to study the biomechanical consequences of C1-2 gapping on construct stiffness using different instrumentations, including a novel 6-screw/3-rod (6S3R) construct, to compare the results to the SOR. We hypothesized that different instrument pattern will reveal significant differences in reduction in ROM among constructs tested.

methodsThe range of motion (ROM) of instrumented C1-2 polyamide models was analyzed in a six-degree-of-freedom spine tester. The models were loaded with pure moments (2.0 Nm) in axial rotation (AR), flexion extension (FE), and lateral bending (LB). Comparisons of C1-2 construct stiffness among the constructs included variations in rod diameter (3.5 mm vs. 4.0 mm), rod material (Ti. vs. CoCr) and a cross-link (CLX). Construct stiffness was tested with C1-2 facets in contact (Contact Group) and in a 2 mm distracted position (Gapping Group). The ROM (°) was recorded and reported as a percentage of ROM (%ROM) normalized to the SOR. A difference > 30% between the SOR and the %ROM among the constructs was defined as significant.

resultsAmong all constructs, an increase in construct stiffness up to 50% was achieved with the addition of CLX, particularly with a 6S3R construct. These differences showed the greatest effect for the CLX in AR testing and for the 6S3R construct in FE and AR testing. Among all constructs, C1-2 gapping resulted in a significant loss of construct stiffness. A protective effect was shown for the CLX, particularly using a 6S3R construct in AR and FE testing. The selection of rod diameter (3.5 mm vs. 4.0 mm) and rod material (Ti vs. CoCr) did show a constant trend but did not yield significance.

conclusionThis study is the first to show the loss of construct stiffness at C1-2 with gapping and increased restoration of stability using CLX and 6S3R constructs. In the correction of a craniocervical deformity, nuances in the surgical technique and advanced instrumentation may positively impact construct stability.

Indexed as

Spinal FusionBiomechanical PhenomenaBone ScrewsCadaverHumansRange of Motion, ArticularBiomechanical studyC1-2Construct stabilityGappingImplant patternInstrumentationMechanical testingROM

Identifiers

PMID33893554
OpenAlexW3152762102

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.