Subtopic Deep Dive
Ossification of Posterior Longitudinal Ligament
Research Guide
What is Ossification of Posterior Longitudinal Ligament?
Ossification of the Posterior Longitudinal Ligament (OPLL) is an ectopic bone formation along the posterior longitudinal ligament of the cervical spine that compresses the spinal cord, causing myelopathy primarily in Asian populations.
OPLL leads to cervical myelopathy through spinal canal narrowing, with surgical interventions like laminoplasty addressing multilevel compression. Studies report postoperative progression in 53 cases (Hirabayashi et al., 1981, 1098 citations). Long-term follow-up shows 78% maintenance of results over 10 years in OPLL patients (Seichi et al., 2001, 391 citations).
Why It Matters
OPLL surgery optimizes neurological recovery, with Hirabayashi et al. (1981) documenting operative results in 53 patients and progression rates influencing technique selection. Laminoplasty preserves motion while decompressing, as Ratliff and Cooper (2003, 391 citations) reviewed for multilevel OPLL cases. Scheer et al. (2013, 667 citations) link cervical alignment to myelopathy outcomes, guiding sagittal deformity correction. Iwasaki et al. (2002, 297 citations) report >10-year laminoplasty results, reducing reoperation needs in Asian cohorts.
Key Research Challenges
Postoperative OPLL Progression
OPLL advances after surgery, worsening myelopathy in some patients. Hirabayashi et al. (1981) observed progression in 53 cases post-laminoplasty. Satomi et al. (1994, 376 citations) noted long-term canal narrowing in 33 OPLL patients.
Surgical Complication Rates
Neurologic deficits occur post-decompression. Yonenobu et al. (1991, 278 citations) reviewed complications in 384 myelopathy cases including OPLL. Epstein (2019, 328 citations) detailed ACDF risks versus laminoplasty.
Predicting Long-Term Outcomes
Factors like alignment affect durability. Seichi et al. (2001) found 78% 10-year stability in OPLL. Iwasaki et al. (2002) identified preoperative occupation and ossification type as predictors over 10 years.
Essential Papers
Operative Results and Postoperative Progression of Ossification Among Patients With Ossification of Cervical Posterior Longitudinal Ligament
Kiyoshi Hirabayashi, Jun Miyakawa, Kazuhiko Satomi et al. · 1981 · Spine · 1.1K citations
Although the pathogenesis of ossification of the cervical posterior longitudinal ligament (OPLL) has not yet been clarified, it has come to be widely recognized that severe cervical myelopathy or r...
Cervical spine alignment, sagittal deformity, and clinical implications
Justin K. Scheer, Jessica A. Tang, Justin S. Smith et al. · 2013 · Journal of Neurosurgery Spine · 667 citations
This paper is a narrative review of normal cervical alignment, methods for quantifying alignment, and how alignment is associated with cervical deformity, myelopathy, and adjacent-segment disease (...
Long-Term Results of Double-Door Laminoplasty for Cervical Stenotic Myelopathy
Atsushi Seichi, Katsushi Takeshita, Isao Ohishi et al. · 2001 · Spine · 391 citations
The short-term results of laminoplasty for cervical stenotic myelopathy were maintained over 10years in 78% of the patients with ossification of the posterior longitudinal ligament, and in most of ...
Cervical laminoplasty: a critical review
John K. Ratliff, Paul R. Cooper · 2003 · Journal of Neurosurgery Spine · 391 citations
Object. The technique of cervical laminoplasty was developed to decompress the spinal canal in patients with multilevel anterior compression caused by ossification of the posterior longitudinal lig...
Long-Term Follow-up Studies of Open-Door Expansive Laminoplasty for Cervical Stenotic Myelopathy
Kazuhiko Satomi, Yukimi Nishu, Touru Kohno et al. · 1994 · Spine · 376 citations
Follow-up at an average time of 7.8 years postoperatively on open-door expansive laminoplasty (EL) was carried out to determine the long-term results of surgery. Thirty-three patients had ossificat...
A Review of Complication Rates for Anterior Cervical Diskectomy and Fusion (ACDF)
Nancy E. Epstein · 2019 · Surgical Neurology International · 328 citations
Background: There are multiple complications reported for anterior cervical diskectomy and fusion (ACDF), one of the most common cervical spine operations performed in the US (e.g. estimated at 137...
Technical Improvements and Results of Laminoplasty for Compressive Myelopathy in the Cervical Spine
T. Itoh, Haruo Tsuji · 1985 · Spine · 302 citations
The laminoplasty reported in Spine 1982 by the author (H.T.) was modified by a technical improvement to obtain a more reliable enlargement of the cervical spinal canal. The technical improvements a...
Reading Guide
Foundational Papers
Start with Hirabayashi et al. (1981, 1098 citations) for core operative results and progression in 53 OPLL cases; follow with Satomi et al. (1994, 376 citations) for 7.8-year laminoplasty follow-up.
Recent Advances
Study Scheer et al. (2013, 667 citations) for cervical alignment in myelopathy; Epstein (2019, 328 citations) for modern ACDF complication rates.
Core Methods
Core techniques: open-door expansive laminoplasty (Hirabayashi, Satomi), double-door laminoplasty (Seichi et al., 2001), with radiographic predictors (Scheer et al., 2013).
How PapersFlow Helps You Research Ossification of Posterior Longitudinal Ligament
Discover & Search
Research Agent uses searchPapers and citationGraph to map Hirabayashi et al. (1981, 1098 citations) as the foundational OPLL paper, revealing clusters around laminoplasty outcomes. exaSearch uncovers Asian cohort studies; findSimilarPapers links Scheer et al. (2013) for alignment-myelopathy ties.
Analyze & Verify
Analysis Agent applies readPaperContent to extract progression rates from Hirabayashi et al. (1981), then verifyResponse with CoVe checks claims against Seichi et al. (2001). runPythonAnalysis computes meta-analysis of JOA scores across 5 papers; GRADE grades laminoplasty evidence as moderate-quality.
Synthesize & Write
Synthesis Agent detects gaps in postoperative progression predictors from Iwasaki et al. (2002), flags contradictions in complication rates (Epstein 2019 vs. Yonenobu 1991). Writing Agent uses latexEditText for surgical comparison tables, latexSyncCitations for 10-paper bibliography, latexCompile for myelopathy review manuscript; exportMermaid diagrams laminoplasty techniques.
Use Cases
"Analyze JOA recovery rates across OPLL laminoplasty studies with Python stats."
Research Agent → searchPapers('OPLL laminoplasty JOA') → Analysis Agent → readPaperContent(Hirabayashi 1981, Seichi 2001) → runPythonAnalysis(pandas mean/std of scores, matplotlib boxplot) → researcher gets CSV of aggregated recovery stats.
"Write LaTeX review comparing laminoplasty vs ACDF for OPLL myelopathy."
Synthesis Agent → gap detection(Iwasaki 2002, Ratliff 2003) → Writing Agent → latexEditText(structured sections) → latexSyncCitations(10 papers) → latexCompile(PDF) → researcher gets compiled manuscript with figures.
"Find code for OPLL radiographic analysis from papers."
Research Agent → citationGraph(Scheer 2013) → Code Discovery (paperExtractUrls → paperFindGithubRepo → githubRepoInspect) → researcher gets Python scripts for cervical alignment metrics.
Automated Workflows
Deep Research workflow synthesizes 50+ OPLL papers into structured report: searchPapers → citationGraph → DeepScan(7-step verify) → GRADE outcomes. Theorizer generates hypotheses on progression predictors from Hirabayashi (1981) + Iwasaki (2002). DeepScan chain verifies alignment-myelopathy links (Scheer 2013) with CoVe checkpoints.
Frequently Asked Questions
What defines Ossification of the Posterior Longitudinal Ligament?
OPLL is ectopic ossification of the posterior longitudinal ligament compressing the cervical spinal cord, causing myelopathy (Hirabayashi et al., 1981).
What are main surgical methods for OPLL?
Laminoplasty (open-door or double-door) decompresses multilevel OPLL; alternatives include ACDF (Ratliff and Cooper, 2003; Seichi et al., 2001).
What are key papers on OPLL outcomes?
Hirabayashi et al. (1981, 1098 citations) reports operative results; Seichi et al. (2001, 391 citations) and Iwasaki et al. (2002, 297 citations) detail 10-year laminoplasty follow-up.
What are open problems in OPLL research?
Postoperative progression prediction and reducing neurologic complications remain challenges (Satomi et al., 1994; Yonenobu et al., 1991).
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Part of the Cervical and Thoracic Myelopathy Research Guide