Evidence map›Paper›PMID 42733909›Full record

ArticleCureus2026

Microsurgical Unroofing to Secure a Safe Corridor for C1 Screws in Bilateral Ponticulus Posticus: A Case Report.

Kyota Kitagawa, Satoshi Maki, Takashi Hozumi, Seiji Ohtori

Abstract readCase Reports
In one paragraph

Article in Cureus, 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

4 authors.

Kyota KitagawaDepartment of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, JPN.
Satoshi MakiDepartment of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, JPN.
Takashi HozumiDepartment of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, JPN.
Seiji OhtoriDepartment of Orthopaedic Surgery, Chiba University Hospital, Chiba, JPN.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Ponticulus posticus (PP) is a bony bridge arising from the posterior arch of C1 toward the superior articular process or lateral mass; when complete, it forms an arcuate foramen over the C1 vertebral artery (VA) groove and may convert the VA path into an osseous canal. This anatomy can narrow the usual corridor for C1 lateral mass screw (LMS) insertion. We report a 68-year-old man who sustained an upper cervical cord injury (ASIA Impairment Scale grade [AIS] B) after a fall. Computed tomography (CT) revealed continuous ossification of the posterior longitudinal ligament and anterior longitudinal ligament from C2 to T1, and magnetic resonance imaging showed canal stenosis due to a retro-odontoid pseudotumor with intramedullary signal change. Dynamic flexion radiograph demonstrated an atlas-dens interval of 5.6 mm and a space available for the spinal cord of 15.5 mm, while three-dimensional computed tomographic angiography identified bilateral complete PP with an aberrant VA course and no symptoms of vertebrobasilar insufficiency. After C1 laminectomy, the arcuate bony bridge was microsurgically unroofed with a 3-mm high-speed burr, enabling direct visualization and protection of the VA with neurosurgical sheets and a Penfield dissector; unroofing was complete on the left and partial on the right based on the bony bridge morphology and the VA exit point. An intraoperative navigation system confirmed screw entry points and trajectories, allowing placement of C1 screws. Immediate postoperative CT confirmed appropriate screw positions. Postoperative vascular imaging was not performed. At three months, the patient's neurological status improved to AIS C, which indicates motor-incomplete spinal cord injury, with no implant-related complications. In bilateral complete PP, the risk of VA injury with C1 LMS has led to divergent recommendations ranging from avoidance to conditional use with protective techniques. Microsurgical unroofing placed the VA under direct visualization and protection, and navigation verified a controlled corridor, supporting intraoperative adjustments in complex C1-2 anatomy. In this setting, microsurgical unroofing with navigation permitted C1 LMS placement under direct VA visualization and protection and may be a reasonable option when a controlled corridor can be created in selected patients.

Indexed as

c1-c2 fixationponticulus posticusspinal cord injuryspinal fusion surgeryvertebral artery (va)

Identifiers

PMID42733909
PMCPMC13571823

What OpenQuestion holds

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Registered trials

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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.