A 52-year-old male patient with a history of rheumatoid arthritis presents for elective knee arthroplasty. On pre-anesthetic evaluation, clinical examination reveals limited mouth opening (25 mm) and a Mallampati score of Grade 3. Which investigation is most appropriate to further assess the airway and predict difficulty with intubation?

Explanation

## Airway Assessment Beyond Mallampati **Key Point:** While the Mallampati score assesses oropharyngeal visibility, a Grade 3 score combined with limited mouth opening (trismus) suggests potential difficult airway. Lateral neck radiography with neck extension helps visualize the cervical spine anatomy and assess for cervical pathology that may compromise airway management. ### Why Lateral Neck Radiograph? In this patient with rheumatoid arthritis and restricted mouth opening: - **Cervical involvement** is common in RA and may cause atlantoaxial subluxation or cervical spondylosis - **Non-invasive screening** before more invasive testing - **Identifies bony obstruction** or malalignment that affects intubation difficulty - **Cost-effective** first-line imaging for suspected cervical pathology ### Mallampati Grading Limitations | Grade | Visibility | Difficulty Risk | |-------|-----------|------------------| | 1 | Soft palate, uvula, fauces | Low | | 2 | Soft palate, uvula | Low–Moderate | | 3 | Soft palate only | Moderate–High | | 4 | Hard palate only | High | **Clinical Pearl:** Mallampati Grade 3–4 + limited mouth opening + cervical disease = **high-risk airway**. Lateral neck X-ray is the appropriate next investigation before considering fiberoptic intubation. **High-Yield:** In rheumatoid arthritis patients, always assess cervical spine mobility and obtain imaging if airway difficulty is suspected. Atlantoaxial subluxation can occur silently. [cite:Gupta Textbook of Anesthesia Ch 5]