後縦靱帯骨化症

BACKGROUND CONTEXT: Ossification of the posterior longitudinal ligament (OPLL) involving the C2 segment poses significant surgical challenges due to anatomical complexity and limited exposure. PURPOSE: This report describes a novel application of the Expanded Shelter Technique to overcome C3-level exposure constraints in the management of continuous C2-C6 OPLL. STUDY DESIGN: This study used a clinical case report. RESULTS: A 60-year-old male presented with progressive neck/shoulder discomfort, right upper limb numbness, and weakness (MRC grade 2 right vs. grade 4 left). Imaging showed multi-level OPLL from C2 to C6, severe canal stenosis, and disc herniations. The Expanded Shelter Technique was performed. Neurological symptoms in the right upper limb resolved on the first postoperative day, with no new neurological symptoms emerging. At the six-month follow-up, neurological symptoms remained absent, and solid bony fusion was confirmed at the graft-vertebral interface. Direct spinal cord decompression was achieved. Subtotal resection of the C3 vertebral body effectively widened the surgical corridor and reduced procedural complexity. CONCLUSIONS: We report a case of continuous cervical OPLL spanning C2-C6 managed with the Expanded Shelter Technique. This approach successfully overcomes C3 exposure constraints through subtotal vertebral body resection and mesh reconstruction, providing a viable anterior decompressive solution for this challenging OPLL subtype.

STUDY DESIGN: This was a retrospective study. OBJECTIVE: To retrospectively analyze the impact of different ossification of the posterior longitudinal ligament (OPLL) characteristics-including upper cervical involvement, concurrent ossification of the anterior longitudinal ligament (OALL), OPLL grades, and OPLL types-on retro-odontoid soft-tissue thickness (ROSTT). SUMMARY OF BACKGROUND DATA: Abnormal thickening of the retro-odontoid soft tissues can lead to the formation of a retro-odontoid pseudotumor (ROP), which may compress the spinal cord. Increased ROSTT and ROP development are associated with pathologies-such as OPLL-as well as cervical biomechanical imbalance. Notably, OPLL may influence ROSTT by altering cervical curvature and biomechanical properties. METHODS: A total of 143 patients with cervical OPLL were enrolled in this retrospective analysis. Patients were divided into subgroups based on the following criteria: upper cervical spine involvement by OPLL, presence or absence of OALL, OPLL grades, and OPLL types. In addition, patients were stratified into the high ROSTT group (≥3.8 mm) and low ROSTT group (<3.8 mm). These subgroups were included in comparative analyses to assess differences in ROSTT, cervical sagittal balance parameters, and cervical range of motion (ROM). RESULTS: Patients with OPLL who had upper cervical involvement, concurrent OALL, or higher OPLL grades exhibited significantly greater ROSTT and reduced ROM of C2-C7 (all P<0.05). Both the cervical ossification index (OP-index) and upper cervical ossification index (UOP-index) were significantly correlated with ROSTT (P<0.05). CONCLUSIONS: This retrospective study of 143 cervical OPLL patients confirms that increased OPLL extent, upper cervical OPLL involvement, and concurrent OALL are significantly associated with ROSTT thickening. In contrast, OPLL type only affects C2-C7 ROM and exerts no significant impact on ROSTT or cervical sagittal balance. For such patients-specifically those with extensive OPLL, upper cervical involvement, or concurrent OALL-close attention should be paid to the further increase in ROSTT and the potential development of ROP.

OBJECTIVES: Traditional Vertebral Body Sliding Osteotomy (VBSO) is technically demanding with variable precision. This study evaluates the surgical precision, clinical efficacy, and learning curve of the novel Suture Anchor-Assisted VBSO (SA-VBSO) for complex cervical myelopathy. METHODS: Seventeen consecutive patients (21 osteotomy vertebrae) underwent SA-VBSO. A suture anchor was utilized for anchor-mediated sliding control, replacing traditional bulky clamps. Precision was quantified using the Adjacent Posterior Vertebral Line (APVL) method to compare planned versus actual sliding. Decompression was assessed via MRI cross-sectional area (CSA) and compression ratios. The learning curve was analyzed using chronological procedural times for osteotomies and cage insertions. RESULTS: All procedures were successful without systematic bias; mean absolute sliding error was 0±1 mm (p=0.68) and Sliding Accuracy Index was 102±13% (p=0.54). Radiographic analysis confirmed robust decompression: mean spinal cord CSA increased from 50±12 to 62±12 mm2 (p<0.001), and compression ratio improved from 24±6 to 43±8% (p<0.001). Sagittal alignment improved significantly (C2-7 Cobb's angle: 3° to 9°, p=0.032). Mean mJOA scores rose from 11±1 to 16±1 (p<0.001). Learning curve analysis demonstrated rapid procedural acceleration, reaching a steady efficiency plateau after 10 to 12 osteotomy segments. CONCLUSIONS: SA-VBSO is a feasible, precise, and potentially reproducible refinement of traditional VBSO. By establishing anchor-mediated sliding control, it resolves the "sliding control dilemma" and features a manageable learning curve, offering a reliable technical alternative for complex anterior cervical reconstruction.

BACKGROUND: Spinal cord infarction is a rare cause of acute neurological deficits and may present as a stroke mimic. Cervical ossification of the posterior longitudinal ligament (OPLL) may increase ischemic vulnerability at the compressed cord level. OBSERVATIONS: A 68-year-old man presented with sudden-onset left hemiparesis and a speech disturbance without preceding trauma. Neurological examination revealed hypophonia without aphasia, facial weakness, tongue deviation, or extraocular movement abnormalities. Contrast-enhanced head and neck CT showed no intracranial hemorrhage or large-vessel occlusion, and intravenous alteplase was administered for suspected acute ischemic stroke. Brain MRI performed 48 hours after symptom onset showed no evidence of acute cerebral infarction. In contrast, cervical MRI demonstrated diffusion restriction at C3 adjacent to severe mixed-type OPLL at C2-3, consistent with spinal cord infarction. Because OPLL-related canal stenosis persisted at the infarct level, posterior decompression with C3-6 laminoplasty was performed on hospital day 8. The patient partially improved postoperatively. LESSONS: This case illustrates that cervical spinal cord infarction associated with OPLL may present as a stroke mimic. Cervical spine imaging should be considered when acute hemiparesis is accompanied by a speech disturbance but cortical or bulbar signs are absent and brain MRI findings are negative. https://thejns.org/doi/10.3171/CASE26294.

PURPOSE: Patients with ossification of the posterior longitudinal ligament (OPLL) may require lumbar surgery due to ossified lesions and degenerative changes. However, risk stratification for lumbar intervention remains underexplored. We aimed to identify predictors of lumbar surgery in patients with OPLL. METHODS: We retrospectively analyzed 178 OPLL patients who underwent whole-spine computed tomography (CT) (2007-2023). Patients were classified according to whether they underwent lumbar surgery. CT obtained prior to lumbar surgery or during conservative follow-up was reviewed. Imaging parameters, including ossification distribution and degenerative changes, were compared between groups and analyzed using multivariable logistic regression to identify independent predictors. RESULTS: Lumbar surgery was performed in 70 (39.3%) patients. The surgery group exhibited higher body mass index and greater prevalence of thoracolumbar ankylosis, thoracic and lumbar OPLL, lumbar ossification of the ligamentum flavum (OLF), and intervertebral disc (IVD) gas. Multivariable analysis identified lumbar OLF (OR, 6.49; 95% CI, 2.60-16.25) and lumbar IVD gas (OR, 5.75; 95% CI, 2.37-13.97) as independent risk factors. Coexisting OPLL and OLF at the same level was associated with younger surgical age and greater neurological severity. CONCLUSIONS: Using whole-spine CT, we demonstrated that patients requiring lumbar surgery frequently exhibited a diffuse whole-spine ossification phenotype, characterized by thoracolumbar OPLL and ankylosis. Lumbar OLF and IVD gas were identified as independent risk factors; notably, lumbar OLF reflects this generalized ossification tendency, whereas disc gas indicates mechanical stress and degeneration. These findings support whole-spine CT-based risk stratification and longitudinal monitoring in patients with OPLL.