Evidence map›Paper›PMID 41253295›Full record

ArticleAsian spine journal2026

Insufficient evaluation of S2 alar iliac screw malposition with the intraoperative inlet view: utility of the obturator inlet and iliac oblique views.

Shun Okuwaki, Toru Funayama, Yohei Yanagisawa, Takahiro Sunami, Takane Nakagawa, Yosuke Ogata, Kotaro Sakashita, Hisanori Gamada, Kousei Miura, Hiroshi Noguchi and 2 more

Abstract read
PubMed Full text at PMC Publisher
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.

Shun OkuwakiDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Toru FunayamaDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Yohei YanagisawaDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Takahiro SunamiDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Takane NakagawaDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Yosuke OgataDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Kotaro SakashitaDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Hisanori GamadaDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Kousei MiuraDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Hiroshi NoguchiDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Hiroshi TakahashiDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.
Masao KodaDepartment of Orthopaedic Surgery, Institute of Medicine, University of Tsukuba, Tsukuba, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

STUDY

designRetrospective observational study. PURPOSE: To evaluate the effectiveness of the inlet view in detecting anterior deviations of the S2 alar iliac (S2AI) screw during spinopelvic surgery and to assess the utility of the obturator inlet (OI) and iliac oblique (IO) views as alternative imaging methods. OVERVIEW OF LITERATURE: S2AI screws are increasingly utilized in spinopelvic fixation due to their biomechanical advantages. However, malpositioning of screws can lead to neurovascular complications. While inlet views in fluoroscopic techniques are generally effective for identifying screw deviations, there are instances where deviations go unnoticed.

methodsWe analyzed data from 101 patients who underwent spinopelvic surgery involving 202 S2AI screws. Postoperative computed tomography (CT) images were reviewed to identify screw deviations. The reconstructed fluoroscopic views from CT, including the inlet, OI, and IO views, were assessed for their effectiveness in detecting deviations. An experimental study using pelvic bone models simulated scenarios where deviations were undetectable in the inlet view but visible in the OI view.

resultsScrew deviations were identified in 12 cases (11.9%) and 13 screws (6.4%), including six screws (3.0%) with anterior deviations and seven screws (3.5%) with posterior deviations. The accurate inlet view detected anterior deviations in three of the five cases analyzed with reconstructed images. However, two cases of anterior deviation were missed due to an insufficient inlet view caused by a 30° caudal tilting angle. In contrast, the OI view successfully identified all cases of both anterior and posterior deviations. In particular, deviations above the arcuate line of the pelvic brim were not detectable in the inlet view.

conclusionsThe inlet view alone is inadequate for detecting anterior deviations, especially those located above the arcuate line of the pelvis. The OI and IO views demonstrated greater effectiveness in identifying deviations, thereby enhancing the accuracy and safety of S2AI screw placement.

Indexed as

Iliac oblique viewInlet viewObturator inlet viewS2 alar iliac screwScrew malposition

Identifiers

PMID41253295
PMCPMC13153971

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.