Nixon's Method of Spleen Percussion
Nixon's method of spleen percussion is a bedside percussion technique used to detect splenomegaly, though it demonstrates the lowest sensitivity (66.7%) among commonly used percussion methods and should not be relied upon as a standalone diagnostic maneuver. 1
Technical Performance of Nixon's Method
Nixon's method is one of three established percussion techniques for assessing splenic enlargement, alongside Traube's space percussion and Castell's method. 2, 1 However, the specific technical details of how to perform Nixon's method are not well-documented in the available clinical literature, unlike the more standardized approaches of Traube's space and Castell's percussion. 3, 2
Diagnostic Accuracy
Nixon's method has the lowest sensitivity (66.7%) among percussion techniques, making it less reliable for detecting splenomegaly compared to alternatives. 1
The specificity of Nixon's method varies considerably between examiners, ranging from 60-100% across different observers, indicating significant interobserver variability. 2
When compared directly to other methods, Castell's percussion and Traube's space percussion demonstrate superior diagnostic performance. 2, 1
Optimal Clinical Approach to Spleen Assessment
Rather than using Nixon's method, clinicians should employ a combined approach using Traube's space percussion followed by palpation when percussion is positive. 3
Recommended Algorithm:
First, perform Traube's space percussion (sensitivity 62-67%, specificity 72-75%), which serves as an effective screening test. 4, 3
If Traube's space is dull, proceed with palpation (sensitivity 44-85.7%, specificity 92-97%), as palpation becomes significantly more accurate when performed after positive percussion (area under ROC curve = 0.87). 3, 1
When both percussion and palpation are positive (concordant-positive), the combined specificity reaches 97%, though sensitivity drops to 46%. 3
Important Clinical Caveats
Physical examination techniques are relatively insensitive but specific for detecting splenomegaly, meaning negative findings do not reliably exclude splenic enlargement. 5, 2
Body mass index significantly affects accuracy: false negative rates increase substantially in obese patients (mean BMI 29.43 kg/m²), while lean patients show much better diagnostic accuracy (area under ROC = 0.83 vs 0.65). 4, 3
High interobserver variability exists across all percussion and palpation methods, regardless of examiner experience level. 2
When Imaging is Indicated
Ultrasound is the recommended initial imaging modality when clinical suspicion for splenomegaly exists, as it is noninvasive, widely available, low cost, and involves no radiation exposure. 6
Normal spleen size is defined as ≤13 cm in vertical length on coronal imaging, with splenomegaly >13 cm considered clinically significant. 7
CT with intravenous contrast should be obtained as second-line imaging (sensitivity 90-100%, specificity 96-100%) when ultrasound findings are non-diagnostic or when evaluating for splenic complications. 6