Evidence map›Paper›PMID 40643818›Full record

ArticleSpine deformity2025

Impact of a novel patient-specific, patient-matched Bezier parametric curve rod platform on proximal junction biomechanics in an in silico thoracolumbar instrumented fusion model.

Franck Le Naveaux, Bahe Hachem, Sasha Vaziri, Varun Puvanesarajah, Saeed Sadrameli, David O Okonkwo, Thomas J Buell, Amit Jain, Hamid Hassanzadeh, Craig Forsthoefel and 4 more

Abstract read
In one paragraph

Article in Spine deformity, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
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

1 citing paper in PubMed.

  1. 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

14 authors.

Franck Le NaveauxNumaLogics, Montreal, QC, H2W 2R2, Canada.
Bahe HachemNumaLogics, Montreal, QC, H2W 2R2, Canada.
Sasha VaziriNeurosurgery and Spine Specialists, Sarasota, FL, USA.
Varun PuvanesarajahDepartment of Orthopaedic Surgery, University of Rochester, New York, NY, USA.
Saeed SadrameliOrlando Neurosurgery, Kissimmee, FL, USA.
David O OkonkwoDepartment of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
Thomas J BuellDepartment of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
Amit JainDepartment of Orthopaedic Surgery, Johns Hopkins University, Baltimore, MD, USA.
Hamid HassanzadehDepartment of Orthopaedic Surgery, Johns Hopkins University, Baltimore, MD, USA.
Craig ForsthoefelIllinois Bone and Joint Institute, Morton Grove, IL, USA.
Reginald FayssouxDesert Orthopaedic Center, Rancho Mirage, CA, USA.
Zachary J TempelMayfield Brain and Spine, Dent, OH, USA.
Alekos A TheologisDepartment of Orthopaedic Surgery, University of CA - San Francisco (UCSF), 500 Parnassus Ave, MUW 3Rd Floor, San Francisco, CA, 94143, USA. alekos.theologis@ucsf.edu.ORCID http://orcid.org/0000-0001-6170-2813
Christopher S AhujaDepartment of Neurological Surgery, Northwestern University, Chicago, IL, USA.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeTo evaluate the biomechanical performance of a novel Bezier surface-smoothed transition rod, and to compare it to conventional and stepped rods, focusing on correction capability, spinal stabilization, instrumentation and spinal loading related to risk of proximal junctional kyphosis (PJK).

methodsA spine finite element model with patient-specific 3D spinal geometry (severe sagittal imbalance from thoracolumbar kyphosis) was used. Surgical instrumentation with five rod types was simulated: (1) constant 6.0 mm diameter, (2) stepped 6.0 mm-5.0 mm diameter, (3) Bezier 6.0 mm-5.5 mm-5.0 mm diameter, (4) constant 5.5 mm diameter, and (5) Bezier 5.5 mm-5.0 mm-4.75 mm diameter. Gravitational forces and flexion movements were simulated to compare load transfer between the spine and instrumentation.

resultsAll rod configurations achieved equivalent sagittal correction. Load distribution analysis showed that Bezier rods provided smoother load transitions and better offloading of proximal segments compared to constant diameter rods. The highest moment sustained by the segment adjacent to the instrumentation was observed with the constant 6 mm rod (9N.m), while the Bezier 5.5-5-4.75 mm rod showed the lowest moment (7.5Nm), indicating reduced stress of 16% on the upper adjacent vertebrae. Similarly, the Bezier rods were more effective in offloading pedicle screws up to 45% with respect to the stiffer rod construct, potentially reducing the risk of PJK.

conclusionsThe simulation analysis demonstrates Bezier rods offer promising biomechanical benefits particularly in load distribution and stress reduction at adjacent levels of long thoracolumbar instrumentation. Future efforts will focus on clinical validation and optimization of patient-specific designs.

Indexed as

KyphosisLumbar VertebraeSpinal FusionThoracic VertebraeBiomechanical PhenomenaComputer SimulationFinite Element AnalysisHumansAdult spinal deformityBiomechanicsFinite element analysisPatient-specific rodsProximal junctional kyphosis

Identifiers

PMID40643818
PMCPMC12634701

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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.