1. Radiological Findings

Based on the provided sagittal MRI (T1/T2-weighted) images:

• Bone bridging is clearly visible at the anterior margins of certain thoracic vertebral bodies and the anterior parts of the intervertebral discs, showing a continuous fusion trend.
• Narrowing of the anterior intervertebral space and irregular erosive changes in the anterior portion of the endplate, while the posterior intervertebral space is either normal or less severely narrowed.
• Local abnormal signals, such as mild edema in the endplate region (or signals developing toward fat replacement, etc.).
• The spine presents an overall kyphotic deformity (posterior curvature, hunched appearance), corresponding to the patient's complaint of “long-term stooping and kyphosis.”
• No obvious intraspinal lesions or serious nerve compression.

2. Potential Diagnoses

Considering the patient’s age, clinical presentations (chest pain, long-standing kyphotic deformity), and radiological findings, possible diagnoses and differential diagnoses include:

1. Progressive Non-infectious Anterior Vertebral Fusion (PAVF or “Copenhagen Syndrome”)
   This condition often begins in childhood but might not be diagnosed or show noticeable symptoms until adulthood. Radiologically, it is characterized by bony fusion occurring at the anterior vertebrae and intervertebral discs, leading to varying degrees of kyphosis. Indicators of infection or severe inflammation are typically absent.
2. Infectious Spondylitis (Spinal Tuberculosis or Pyogenic Spondylitis)
   Typically shows distinct signs of infection, such as vertebral destruction, paravertebral abscess formation, or peripheral tissue edema, alongside elevated inflammatory markers (CRP and ESR). Such evidence is lacking here, making this diagnosis less likely.
3. Ankylosing Spondylitis
   Commonly involves the sacroiliac joints first and can present with a “bamboo spine” appearance. It usually affects the posterior spine, leading to ligamentous ossification and joint stiffness, which differs from PAVF. Clinically, characteristic inflammatory back pain and other SI joint manifestations are typical.
4. Congenital Hemivertebra or Vertebral Fusion and Other Congenital Spinal Deformities
   Often identified during childhood check-ups or early development, usually accompanied by irregular vertebral shapes or congenital structural anomalies. However, this case aligns more with a progressive intervertebral fusion pattern.

3. Final Diagnosis

Considering the clinical history (long-standing kyphotic deformity, mild chest pain, no evident signs of infection or nerve compression) and radiological findings (partial anterior thoracic intervertebral fusion, kyphotic deformity), along with published case reports describing this rare spinal entity, the most likely diagnosis here is:

Progressive Non-infectious Anterior Vertebral Fusion (PAVF, also known as Copenhagen Syndrome).

Further confirmation could include:

• Reviewing spine images or medical history from childhood or adolescence to establish disease duration and progression.
• Checking inflammatory markers (CRP, ESR, etc.) to rule out infection or other autoimmune pathologies, depending on clinical suspicion.
• Obtaining a spinal CT with 3D reconstruction as needed, to assess the extent of bony fusion more comprehensively.

4. Treatment Plan and Rehabilitation Program

4.1 Treatment Strategy Overview

• Conservative Treatment: Most PAVF patients experience slow disease progression with mild clinical symptoms. Symptomatic treatments may include pain relievers, anti-inflammatory drugs, physical therapy, and postural correction exercises.
• Bracing or Orthotic Therapy: For those exhibiting progressive kyphotic deformities, spinal bracing could slow or partially correct the deformity.
• Surgical Treatment: If the kyphosis is significantly severe or leads to neurological compromise, surgical intervention (e.g., osteotomy correction, pedicle screw fixation, spinal fusion) might be warranted. Decisions depend on the degree of deformity, neurological symptoms, and impact on the patient’s quality of life.

4.2 Rehabilitation / Exercise Prescription

Given the pathology of PAVF, rehabilitation should focus on maintaining or improving spinal stability, correcting posture, and alleviating pain, following a gradual and individualized approach. A recommended FITT-VP (Frequency, Intensity, Time, Type, Volume/Progression) model could include:

• Frequency: 3–5 sessions per week for spinal stability and posture exercises.
• Intensity: Begin with low intensity, avoiding extreme twisting or heavy-load flexion and extension. Progress gradually according to tolerance.
• Time: 20–30 minutes per session, which can be modified based on fatigue level. Sessions may be split into segments, such as 10–15 minutes in the morning, afternoon, or evening.
• Type:
  • Core strengthening exercises (e.g., planks, bridge exercises) to enhance trunk and back support.
  • Flexibility and stretching exercises targeting the shoulders and thoracic spine, paired with appropriate joint mobility routines.
  • Postural correction drills: Can utilize basic yoga or Pilates movements, avoiding overstretching.
  • Breathing techniques: Improve thoracic cage mobility and help relieve chest discomfort.
• Volume/Progression: As muscle strength and flexibility improve, progressively increase repetitions, duration, or resistance under professional guidance. Avoid abrupt changes in training intensity.

Special considerations: If the patient has low bone density or compromised cardiopulmonary function, the exercise regimen should be planned and adjusted under medical and rehabilitation specialist supervision to ensure safety.

Disclaimer: The above report is based on current imaging and clinical information for reference only. It should not replace an in-person consultation or a detailed, personalized treatment plan by a qualified healthcare provider. Specific treatment and rehabilitation strategies should be finalized after a comprehensive evaluation of the patient's medical history, physical examination, and laboratory/imaging findings.