CSD has gained increasing clinical recognition as a distinct entity characterized by anterior osteophyte-induced esophageal compression. The disorder typically manifests with insidious-onset symptoms including pharyngeal foreign body sensation, progressive dysphagia, and voice changes, which are frequently misinterpreted as chronic laryngopharyngeal inflammation or functional gastrointestinal disorders (1, 2). CSM, the most prevalent spinal cord disorder in adults, arises from progressive cord compression secondary to degenerative alterations encompassing intervertebral disc collapse, posterior osteophyte formation, and ligamentous hypertrophy. This condition frequently leads to irreversible neurological deficits, substantially impairing patients' functional capacity and quality of life (3). The simultaneous presentation of CSD with CSM remains a rare clinical phenomenon, with limited documented cases in medical literature.

A 51-year-old male patient presented with a two-year history of progressively worsening dysphagia, which had significantly deteriorated over the preceding month. Previous treatment for suspected pharyngitis provided no meaningful relief. Concurrently, the patient reported six months of bilateral lower extremity weakness accompanied by a characteristic “walking on cotton” sensation, manifesting as slowed and unsteady gait during level walking, exacerbation of bilateral lower limb pain and numbness after approximately 100 meters of ambulation, and dependence on assistance for stair climbing. Neurological examination of the upper extremities revealed mildly reduced superficial cutaneous sensation, slightly hyperactive deep tendon reflexes, preserved muscle strength, and minimally delayed but functionally intact fine motor coordination. Lower extremity assessment demonstrated cutaneous numbness, grade V quadriceps strength, and mild weakness (grade IV) in tibialis anterior, ankle dorsiflexion, and great toe extension. Trunk sensation and bladder function remained intact. Positive Hoffmann signs were observed. Preoperative functional assessments yielded a Japanese Orthopaedic Association (JOA) score of 12, Neck Disability Index (NDI) of 66% (indicating severe disability), and Functional Oral Intake Scale (FOIS) level 4. Laboratory investigations, including complete blood count, C-reactive protein, thyroid function tests, and antinuclear antibody panel, returned normal results, effectively excluding inflammatory, autoimmune, or metabolic pathologies. Cervical ultrasonography revealed no thyroid enlargement or nodular lesions to suggest extrinsic compressive pathology. Abdominal ultrasound demonstrated no evidence of hiatal hernia or structural abnormalities at the gastroesophageal junction. The absence of heartburn, acid regurgitation, or unintended weight loss further argued against gastroesophageal reflux disease or malignancy. Additionally, the lack of meal-related symptom variability and negative history of neuromuscular disorders (e.g., myasthenia gravis) diminished the likelihood of primary esophageal dysmotility. Endoscopic evaluation identified pharyngeal wall protrusion with concomitant esophageal lumen narrowing (Figure 1A). Radiographic studies, including cervical plain films (Figures 1B–D), computed tomography (CT) scans (Figures 1G,H), and three-dimensional CT reconstructions (Figures 1E,F), demonstrated anterior osteophytic bridging at C4–6 vertebral levels with corresponding retropharyngeal displacement, OPLL spanning C3–7, and calcification of the ligamentum nuchae. Cervical magnetic resonance imaging (MRI) (Figures 1I,J) and CT myelography (Figures 1K,L) revealed posterior disc herniation at C3/4 and C4/5 levels, resulting in spinal cord compression.

Radiological evaluation demonstrated anterior osteophytes with bridging ossification at C4–6 vertebral levels, forming a localized osseous protrusion directly compressing the retropharyngeal space. These findings coexisted with OPLL spanning C3–7 and multilevel intervertebral disc herniation from C3/4 to C6/7, collectively constituting the characteristic degenerative “tetrad”: osteophytosis, ligamentous calcification, disc degeneration, and segmental instability. This pathological confluence generated dual compressive mechanisms: the prominent C4–5 anterior osteophyte chronically impinged on the posterior esophageal wall, where repetitive swallowing-induced friction risked mucosal inflammation or ulceration, while OPLL and herniated discs occupied the ventral spinal canal, exposing the cord to static compression (bony encroachment) and dynamic compression (ligamentous infolding during cervical motion). Additionally, ligamentum nuchae calcification suggested chronic biomechanical stress, emphasizing the necessity of restoring spinal stability during surgical intervention.

Diffuse idiopathic skeletal hyperostosis (DISH), a non-inflammatory disorder characterized by spinal ligament and entheseal calcification, is diagnosed radiographically using Resnick criteria requiring flowing anterolateral calcification across ≥4 contiguous vertebrae (4). Hallmark features include anterior longitudinal ligament ossification, predominantly in the thoracic spine (5). Imaging modalities such as radiography, CT, and MRI remain critical for assessing DISH severity (5). Differential diagnosis must exclude spinal osteoarthritis and ankylosing spondylitis, distinguished by absent sacroiliitis (vs. ankylosing spondylitis) (5) and preserved bone density (vs. metabolic bone diseases) (6). In this case, contiguous anterior ligament calcification from C4–7 (Figure 1H) confirmed DISH coexistence with disc herniation and OPLL.

Currently, there is a lack of clear epidemiological data on the coexistence of CSD and CSM. Existing research predominantly focuses on exploring the pathological mechanisms and optimizing treatment strategies for individual conditions. While studies on single pathologies still provide valuable insights for managing complex cases, there remains a significant research imbalance: CSD-related studies are relatively scarce compared to the well-established evidence-based system for CSM surgical treatment. This disparity highlights the need for cautious integration of surgical experiences from both conditions, combined with personalized assessments when formulating treatment plans for coexisting cases.

For severe CSD refractory to conservative treatment, anterior osteophyte resection combined with selective intervertebral fusion demonstrates significant efficacy. Surgical strategy selection depends on osteophyte distribution patterns and cervical stability assessments. In a case of non-contiguous osteophytes (C3/4 and C6/7 dual-level compression), osteophyte resection with two-level non-contiguous Zero-Profile fusion effectively relieved dysphagia while maintaining cervical stability through precise segmental fixation, with complete symptom resolution and no recurrence reported at 9-month follow-up (7). For a case of continuous multilevel lesions (C4–6 anterior giant osteophytes with disc herniation compressing the nerve root), three-level continuous ACDF achieved complete osteophyte removal and simultaneous disc pathology management, though postoperative outcome data require further validation (8). A clinical study of 14 patients (2009–2015) confirmed the long-term safety of this approach, showing significant swallowing improvement with no osteophyte recurrence or cervical instability during average 50-month follow-up. Notably, three cases required supplemental anterior plate fixation due to intraoperative segmental instability, emphasizing the importance of dynamic stability assessment (9). However, current evidence has limitations: small sample sizes in case reports, insufficient follow-up duration, and lack of evaluation for adjacent segment degeneration risk after multilevel fusion. Large-scale prospective studies are needed to clarify surgical indications and long-term outcomes across different techniques.

The surgical management of CSM necessitates a comprehensive assessment of compression topography, involved spinal segments, and biomechanical stability. Anterior surgical strategies, including ACDF and anterior cervical corpectomy and fusion (ACCF), serve distinct yet complementary roles. ACDF is preferentially employed for single- or multilevel disc herniation or focal osteophytic compression (10, 11), offering advantages in cervical alignment correction (12, 13) and lower complication rates (operative time, blood loss, and overall complication incidence compared to ACCF) (14, 15), though with potential accelerated adjacent segment degeneration (12, 13). In contrast, ACCF facilitates extensive decompression via vertebral body resection, demonstrating particular utility in multivertebral pathologies or severe structural compromise (16). While achieving more complete neural decompression (16), this technique carries elevated procedural complexity and complication risks (17). Consequently, ACDF remains the principal anterior approach (18), with ACCF reserved for cases requiring broad ventral decompression (19). Posterior approach selection is guided by stability requirements: laminoplasty preserves segmental mobility through expansive canal enlargement, optimally suited for multilevel OPLL with preserved spinal alignment (20–22), whereas laminectomy with instrumented fusion addresses kyphotic deformity or instability through posterior column stabilization (23–25). For CSM patients, through corresponding surgical treatment, mild-to-moderate cases (especially those with better preoperative neurological function) can achieve favorable neurological recovery (26), while severe cases, despite increased surgical risks, can still attain significant functional improvement (27).

The rationale for selecting a right anterior approach for osteophytectomy combined with two-level ACDF (C3/4, C4/5) includes the following considerations: (1) The C4–5 anterior osteophyte, exhibiting the largest bridging formation, constituted the primary pathological substrate for dysphagia, while concomitant C3/4 and C4/5 disc herniations with OPLL generated critical ventral spinal cord compression. (2) Conservative management of C5/6 and C6/7 disc herniations with mild cord compression aimed to preserve segmental mobility at these levels, potentially mitigating adjacent segment degeneration (ASD) risk through reduced iatrogenic alterations in load distribution and range of motion associated with additional fusion procedures (28–30). (3) The retained C6–7 anterior osteophytes and multilevel OPLL provided partial fusion-like stabilization, potentially slowing degenerative progression.

The two-level ACDF (C3/4, C4/5) with zero-profile interbody fusion devices—innovative implants integrating interbody fusion with low-profile fixation, obviating anterior plating—offered distinct advantages over traditional plate-screw systems. This design minimizes posterior esophageal irritation, significantly reducing postoperative dysphagia incidence (31), while demonstrating lower rates of adjacent level ossification development (ALOD), ASD, and hardware loosening (32). Biomechanically, these devices optimize cervical lordosis restoration and intervertebral height maintenance (33). Technical challenges arose during high cervical (C3/4) implantation due to mandibular interference limiting screw trajectory, suggesting future instrumentation modifications for enhanced anatomical adaptability. Preservation of C4/5–C5/6 osteophytes and OPLL was intentional, leveraging their stabilizing effects analogous to spontaneous fusion.

The rationale for foregoing laminoplasty despite extensive C3–7 OPLL included predominant ventral compression from disc pathology rather than continuous OPLL bridges, coupled with adequate spinal canal reserve space achieved through anterior decompression. Long-term surveillance remains crucial to validate anterior-only decompression efficacy in multilevel hybrid pathologies. Future advancements may integrate 3D-printed anatomical modeling for preoperative osteophyte resection simulation and cage positioning optimization, complemented by finite element analysis to predict ASD patterns and refine biomechanical surgical planning.