The Schnur Sliding Scale chart is an evaluation method for physicians to use on individuals considering breast reduction surgery. This method was developed by a plastic surgeon for use in a study to determine the number of women who had breast reduction surgery for medical reasons only. Body surface area, along with average weight of breast tissue removed is incorporated into the chart to indicate the reason/motivation of the individual for breast reduction surgery.

If the individual's body surface area and weight of breast tissue removed fall above the 22nd percentile, then the surgery is considered medically necessary with the appropriate criteria. If the individual's body surface area and weight of breast tissue removed fall below the lower 22nd percentile, then the surgery is deemed not medically necessary.

The original study did not address individuals with a body surface area greater than 2.55. BlueCross BlueShield of Tennessee utilized a mathematical equation in an attempt to address the greater body surface area (BSA) numbers. The data exhibited characteristics of an exponential trend. Using an exponential model (y=a^x), the grams of tissue removed for those with BSA > 2.55 were extrapolated.

Body surface area and average breast tissue removed above 22nd percentile

 
Body Surface
Area (m2)

Average grams of tissue per breast to be removed

 
Body Surface
Area (m2)

Average grams of tissue per breast to be removed

1.35

199

3.10

4351

1.40

218

3.15

4750

1.45

238

3.20

5186

1.50

260

3.25

5663

1.55

284

3.30

6182

1.60

310

3.35

6750

1.65

338

3.40

7369

1.70

370

3.45

8045

1.75

404

3.50

8783

1.80

441

3.55

9589

1.85

482

3.60

10468

1.90

527

3.65

11428

1.95

575

3.70

12476

2.00

628

3.75

13619

2.05

687

3.80

14867

2.10

750

3.85

16230

2.15

819

3.90

17717

2.20

895

3.95

19340

2.25

978

4.00

21112

2.30

1068

4.05

23045

2.35

1167

4.10

25156

2.40

1275

4.15

27459

2.45

1393

4.20

29972

2.50

1522

4.25

32716

2.55

1662

4.30

35710

2.60

1806

4.35

38977

2.65

1972

4.40

42543

2.70

2154

4.45

46435

2.75

2352

4.50

50682

2.80

2568

4.55

55316

2.85

2804

4.60

60374

2.90

3061

4.65

65893

2.95

3343

4.70

71915

3.00

3650

4.75

78487

3.05

3985

4.80

85658

1

Schnur, Paul L, et al., "Reduction Mammaplasty: Cosmetic or Reconstructive Procedure?" Annals of Plastic Surgery. Sept 1991; 27 (3): 232-7.

Simplified formula for calculation of body surface area:

(BSA (in m2) = [height (cm)] 0.718 X [weight (kg)] 0.427 X .007449).

See website listed below for easy calculation:

http://www.bcbst.com/providers/calculator.asp 

BlueCross BlueShield of Tennessee Use Only