What is the best method to assess post-operative pain, including scoring systems?

Best Methods for Assessing Post-Operative Pain

For Communicating Patients

The 0-10 Numeric Rating Scale (NRS) administered visually is the gold standard for post-operative pain assessment in patients who can self-report. 1

Self-Report Scales (First-Line)

• Patient self-report is the reference standard for pain assessment in all patients who can communicate reliably 1
• The 0-10 NRS Visual (NRS-V) format demonstrates the highest success rate (91%) compared to other scales, with the best sensitivity, negative predictive value, and accuracy 1
• The NRS-V should be presented in a vertical format for optimal patient comprehension 1
• For patients unable to use numerical scales, the Verbal Descriptor Scale (VDS) with descriptors (no pain, mild, moderate, severe, extreme pain) is the recommended alternative 1

Key Assessment Principles

• Pain must be assessed both at rest AND on movement (cough, mobilization) to capture functional pain levels 1
• Assessment should focus on present pain rather than pain over previous hours 2
• Validated pain scales must be incorporated into treatment planning, ongoing evaluation, and adjustment processes 1
• Pain assessment should be performed multiple times daily in every post-operative patient 2

For Non-Communicating Patients

For patients unable to self-report, use the Behavioral Pain Scale (BPS/BPS-NI) or Critical-Care Pain Observation Tool (CPOT), which demonstrate the greatest validity and reliability. 1

Behavioral Assessment Tools by Population

• Modified FLACC scale for non-communicating children (birth to 18 years): assesses 5 behavioral items—face, legs, activity, screams, consolability 1
• ALGOPLUS scale for elderly patients: a score ≥2/5 diagnoses pain with 87% accuracy 1
• BPS and CPOT for critically ill adults: these tools have the strongest psychometric properties (scores 15-20 indicating very good validity) 1

Important Caveat

• Observational pain scales are inherently less reliable than patient-reported metrics and systematically lead to underestimation of pain 1, 2
• However, they should still be applied when patient self-report is impossible 1

Screening for High-Risk Patients

Pre-Operative Risk Assessment

Identify vulnerable patients during pre-operative evaluation using the APAIS scale (Amsterdam Preoperative Anxiety and Information Scale) to measure anxiety and information needs. 1

• Screen for preoperative pain (even distant from surgical site), chronic opioid use, anxiety, depression, and catastrophizing—all predict severe post-operative pain 1, 3
• High-risk surgical procedures include thoracotomy, breast surgery, sternotomy, and iliac crest sampling 1, 3
• Surgery duration >3 hours increases risk 1

Post-Operative Risk Monitoring

Use the DN4 scale to identify early neuropathic pain, which predicts chronic post-surgical pain (CPSP). 1

• Monitor for high pain intensity on numerical scales, prolonged pain duration, and persistent anxiety/depression—all risk factors for CPSP 1, 3
• Sudden increases in pain with tachycardia, hypotension, or fever require urgent comprehensive evaluation for complications (bleeding, anastomotic leak, DVT) 1

Common Pitfalls to Avoid

• Do not rely solely on pain scores at rest—functional assessment during movement is critical for guiding therapy 1
• Avoid assuming that incremental shifts on NRS directly correlate with clinical meaningfulness—percentage reduction in pain severity better predicts patient-perceived improvement 4
• Never use Wong-Baker FACES scale in adults—it results in artificially higher pain scores and was designed for children 1
• Do not use the Visual Analog Scale (VAS) as primary tool—it has lower success rates (66%) compared to NRS-V (91%) 1
• Assessment by nurses or physicians systematically underestimates pain—always prioritize patient self-report when possible 2

Emergency General Surgery Considerations

• Emergency surgery is associated with more severe post-operative pain than elective procedures and requires specific attention 1
• Periodic reassessment using validated systems is mandatory to evaluate treatment response and allow adjustments 1
• Pain assessment tools must account for developmental, cognitive, educational, cultural, and language differences 1