Table 1.

Scoring system of the Lémann Index.^15,16

Severity scale based on complications and surgical history 15
Severity	Definitions
	Stricturing lesions		Penetrating lesions		Surgical procedures
Grade 0	Normal		Normal		None
Grade 1	Wall thickening <3 mm and/or segmental enhancement without prestenotic dilatation		–		–
Grade 2	Wall thickening ≥3 mm and/or mural stratification without prestenotic dilatation		Deep transmural ulceration		Bypass diversion or stricturoplasty
Grade 3	Stricture with prestenotic dilatation		Abscess or any type of fistula		Resection
Coefficients for the Lémann Index calculation 16
Organ	Complication	Grade of complication	Complication coefficient	Organ coefficient	Notes
Upper tract (oesophagus, stomach, duodenum)	Stricture	2	3.5	2.0	Grade 1 strictures, and grade 1 and grade 2 penetrating are not included in the evaluation
	Stricture	3	3.5
	Penetrating	3	2.0
Small bowel (20 segments of 20 cm)	Stricture	1	1.0	5.0	Grade 1 penetrating complications are not included in the evaluation
	Stricture	2	2.5
	Stricture	3	5.0
	Penetrating	2	1.5
	Penetrating	3	4.0
Colon and rectum	Stricture	2	2.0	3.5	Grade 1 strictures are not included in the evaluation
	Stricture	3	5.5
	Penetrating	1	1.0
	Penetrating	2	2.5
	Penetrating	3	4.5
Anus	Stricture	2	1.5	3.5	Grade 1 strictures, and grade 1 and grade 2 penetrating are not included in the evaluation
	Stricture	3	3.5
	Penetrating	2	2.5
	Penetrating	3	3.5

Lémann calculation: (number of segments with each complication × complication coefficient × organ coefficient). As an example, a patient with one frank ileal 15-cm-long stricture (stricturing grade 3) with deep transmural ulceration in the same tract (penetrating grade 2) will have a Lémann score of (1 × 5 × 5 + 1 × 1.5 × 5) = 32.5.