Evidence map›Paper›PMID 41253296›Full record

ArticleAsian spine journal2026

Impact of car seat recline angle on global spinal alignment and seat belt positioning: a prospective observational study in Japan.

Norihiro Nishida, Tomohiro Izumiyama, Ryusuke Asahi, Hidenori Suzuki, Masahiro Koike, Masahiro Funaba, Kazuhiro Fujimoto, Yusuke Ichihara, Yogesh Kumaran, Hiroshi Hamano and 2 more

Abstract read
In one paragraph

Article in Asian spine journal, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing 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

0 citing papers in PubMed.

No citing paper in PubMed yet.

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

12 authors.

Norihiro NishidaDepartment of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Japan.
Tomohiro IzumiyamaCrash Safety Development Department, Vehicle Development Division, Mazda Motor Corporation, Fuchu, Japan.
Ryusuke AsahiCrash Safety Development Department, Vehicle Development Division, Mazda Motor Corporation, Fuchu, Japan.
Hidenori SuzukiDepartment of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Japan.
Masahiro KoikeDepartment of Radiological Technology, Yamaguchi University Hospital, Ube, Japan.
Masahiro FunabaDepartment of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Japan.
Kazuhiro FujimotoDepartment of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Japan.
Yusuke IchiharaDepartment of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Japan.
Yogesh KumaranEngineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, OH, USA.
Hiroshi HamanoCrash Safety Development Department, Vehicle Development Division, Mazda Motor Corporation, Fuchu, Japan.
Shigeru SugimotoCrash Safety Development Department, Vehicle Development Division, Mazda Motor Corporation, Fuchu, Japan.
Takashi SakaiDepartment of Orthopaedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

STUDY

designProspective observational radiographic study. PURPOSE: To evaluate how different car seat recline angles affect global spinal alignment and lap belt positioning in healthy adults, and to assess the influence of demographic factors on these changes. OVERVIEW OF LITERATURE: Seated posture alters global spinal alignment and may contribute to spinal symptoms, especially in individuals with adult spinal deformity (ASD) or following spine surgery. However, radiographic data on reclined seated postures and their impact on spinal alignment and restraint safety remain limited.

methodsLateral radiographs were obtained from 100 healthy adults in standing and seated postures at 25°, 35°, and 45° recline angles. Spinal parameters (cervical lordosis, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and T1 spinopelvic inclination) and seat belt metrics (X-value, Z-value, and lap belt angle) were measured. Multivariate regression was used to assess associations with sex, age, height, and body mass index (BMI).

resultsReclining reduced cervical/lumbar lordosis and sacral slope, while thoracic kyphosis and pelvic tilt increased. Higher BMI was associated with a cranially shifted and more horizontal lap belt. Taller individuals showed greater T1 spinopelvic inclination and pelvic parameters. Females exhibited more pronounced thoracic kyphosis and pelvic retroversion across reclining angles.

conclusionsCar seat recline significantly alters spinal alignment and seat belt positioning, with changes influenced by age, height, and BMI. These findings support ergonomic improvements in seat design and may inform surgical planning for ASD.

Indexed as

AutomobileBody mass indexSeat beltSitting positionSpine

Identifiers

PMID41253296
PMCPMC13153979

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC
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.