The Lund-Mackay score is a CT-based scoring system for chronic rhinosinusitis 1 and is popular due to its simplicity and high inter and intra-observer reliability 6,7.
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Lund-Mackay score
When reading a CT scan of the paranasal sinuses and ostiomeatal complex, the reader assigns each sinus a score of:
no abnormality: 0 points
partial opacification: 1 point
complete opacification: 2 points
N.B. ostiomeatal complex is scored differently:
not obstructed: 0 points
obstructed: 2 points
The sinuses are grouped into:
anterior ethmoidal cells
posterior ethmoidal cells
Each side is graded separately. A combined score of up to 24 is possible. Of note, an aplastic (absent) frontal sinus receives a score of 0.
The method is intentionally simplistic, for the sake of minimizing interobserver variability and expediting its application 2. Thus, it lends itself to application by non-radiologists and in clinical studies 1. Despite its simplicity, it correlates well with disease severity (higher scoress associated with worse symptoms 7), extent of surgery, treatment response (higher pre-FESS scores have better outcomes 7), complication rates, even independent of the extent of surgery 3.
Modified Lund-Mackay (Zinreich) score
For a more accurate representation of disease burden modifications were proposed to the original system, further subdividing the assessment categories. In the modified staging system the reader assigns a score ranging from 0 to 5 based on the percentage of sinus opacification caused by mucosal thickening:
0%:
<25%: 1 point
26-50%: 2 points
51-75%: 3 points
76-99%: 4 points
100%: 5 points
N.B. the ostiomeatal complex is scored differently:
0 (normal)
1 (partially obstructed)
2 (completely obstructed)
Otherwise the assessment is the same, sides are graded separately, resulting in a maximum total score of 54. It has been shown that the modified system better represents disease burden than the original Lund-Mackay score 4,5.
History and etymology
This scoring system is named after its developers, British rhinologists Valerie J Lund and Ian S Mackay.