Total Body Surface Area in Burns

Mar 13, 2021 6 min read
Total Body Surface Area in Burns

The total body surface area (TBSA) of a burn can be calculated with a Lund and Browder Chart, Wallace Rule-of-Nines or the palmar method. An accurate estimation of a burn guides acute management, fluid resuscitation, nutrition supplementation and prognosis.

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Lund and Browder vs Rule-of-9s vs Palmar

The Lund-and-Browder Chart, Wallace Rule-of-Nines and the palmar method are different ways to calculate and estimate the total body surface area (TBSA) of a burn. This table compares the different formulas:

Lund & BrowderRule of 9sPalmar
TheoryStandardised age-based assessmentBody is divided in 9% areas. Patients palm is 1%
Pro’s“Gold-standard” accuracy EfficientMinor Burn Estimation 
Con’sInefficientOver-estimation User variability

Table Comparison of different methods to calculate a burn percentage – Lund and Browder, Rule of Nines, Palmar Method.

According to the National Burn Repository, the mean burn size is 13.4% of the total body surface area​1​. These estimations are heavily user dependent which may result in over-estimation and significant inter-rater variability​​2​. This is, however, an issue for all traditional burn estimation techniques.


Lund and Browder Chart

The Lund and Browder Chart is considered the gold standard in burn surface area calculations. Since its first publication in 1944, this formula has established accuracy. Its limitation is in relation to clinical inefficiency.

What is the Lund and Browder Chart?

The Lund and Browder (LB) chart, which was developed in 1944​3​, is the most broadly used tool worldwide to calculate the total body surface area of a burn.

Lund and Browder chart is the most accurate graphical record of the extent of the burn​4​. Unlike other burn surface area formulas, it accounts for variation in body shape with age. This means it can be used in adults and children. For example, the area of the head makes up a relatively large portion of the total skin area in infants as compared with adults. This proportion is counterbalanced in infants by the smaller area of the thighs and legs. The Lund and Browder chart takes these factors into consideration for full thickness and partial thickness burns.

Lund and Browder Chart - Calculate Total Body Surface Area  Percentage (TBSA%) in Burns
Lund and Browder Chart – Calculate Total Body Surface Area Percentage (TBSA%) in Burns

Positives

The main benefit of using the Lund and Browder Chart is its accuracy. Studies have compared different burn calculation methods. Lund and Browder chart, on average, provides a 3% more accurate calculation of total body surface area burnt with less variability that using Wallace’s Rule of Nines​4​.

Negatives

Weaknesses with the Lund and Browder chart are:

  • Difficulties in assessing lateral burns
  • Lack of anatomical landmarks for reference
  • Inability to accurately represent obese
  • Less efficient than Wallace Rule-of-Nines or the 1% palmar method.

Wallace Rule-of-Nines

The Wallace Rule of Nines is a clinically efficient and accurate method to calculate the total body surface area of a burn. It is calculated by dividing the body into percentages of 9. Limitations are noted in the paediatric and obese population.

What is the Wallace Rule-of-Nines?

The Rule of Nines can be used as an alternative to the Lund and Browder Chart for calculating the total body surface area (TBSA) involved in burn patients.  It was first described by E.J. Palaski and C.W. Tennison in 1947 and later published by Wallace in 1951​5​. It is commonly used in healthcare practice because of its clinical efficiency and proven accuracy​6,7​

The Rule of Nines is calculated by assigning percentages to different areas of the body. It is for full-thickness and partial thickness burns. This is described in the table below:

Rule-of-9sTotalSubdivision 
Head9%Anterior Head = 4.5%
Posterior Head = 4.5%
Torso 18%Chest = 9%
Abdomen = 9%
Back18%
Each Arm9%Anterior Arm = 4.5%
Posterior Arm = 4.5%
Each Leg18%Anterior Leg = 9%
Posterior Leg = 9%
Perineum1%


Rule of Nines Online Calculator

For some, it is easier to visualise the Rules-of-9 when calculating the total body surface area of a burn. This is illustrated in the image and be downloaded as a PDF below.

Calculating the total body surface area of a burn with Wallace Rule of Nines
Calculating the total body surface area of a burn with Wallace Rule of Nines

Positives

The main benefit of using the Wallace Rule of nines is the clinical efficiency. It is simple to use and easy to remember. It is also infrequent to underestimate a burn using this technique.

Negatives

The Rule of Nines can often over-estimate the total body surface area percentage of a burn​4​.

There is a concern among clinicians of the accuracy of the Rule of Nines pertaining to the obese and pediatric populations. The Rule of Nines can be best used in patients greater than 10 kilograms and less than 80 kilograms if defined by BMI as less than obese​8​.

Infants have proportionately larger heads which alters the surface area contribution of other major body segments. A “Rule of Eights” better approximates infants weighing less than 10 kg.” This rule dictates approximately 32% TBSA for the patient’s trunk, 20% TBSA for the head, 16% TBSA for each leg, and 8% TBSA for each arm​8​.


Palmar Method

The Palmar Method is the simplest calculator of a burn’s skin percentage. By utilising the patients palm, this technique is ideal for small and scattered burns. It is limited by user and patient variability.

What is the Palmar Method?

The palmar method is the simplest way to calculate the total body surface area of a burn. To simplify calculations, the palmar method is often described as representing 1% of the patients totally body surface area. Recent literature review has conclude that palm and digits is 0.8% and the palm without digits is 0.5% of the patient’s body surface area.

NICE guidelines for Burns and Scalds recommend the palm including digits in the estimation of smaller or scattered burns.

The Palmar Method use to calculate the total body surface area percentage of a burn
The Palmar Method use to calculate the total body surface area percentage of a burn

The technique raised controversy as to whether the palm including digits or palm excluding digits should be used. Confusion amongst healthcare professionals has been noted in the literature​9​. In larger burns, there is a reported 10-20% burn estimation when using the palmar method​10​. For deeper burns, consider reading our scar managementarticle.


FAQs


How do you calculate the total body surface area (TBSA) of a burn?

There are 3 common methods to estimate the total body surface area of a burn: Lund and Browder Chart, Wallace Rule-of-Nines, Palmar Method. These 3 calculations have an established role in the primary assessment of burns

How do you calculate the Rule of Nines?

The rule of nines is an efficient method to quickly determine the surface area of a burn. It is based on the principle that the body is made up of individual 9% areas, which total to 100%.

Wallace Rule of Nines


What percentage of burns is fatal?

There is no exact percentage that can predict mortality of burns. There are 3 major risk factors of a fatal burn. These are: an age of more than 60 years, burn size of more than 40 percent of body-surface area, and inhalation injury. This is further explored in a landmark publication in the NEJM.


References

For further reading, consider search “Total Body Surface Area” in Google Scholar or PubMed.

  1. 1. Miller S, Bessey P, Schurr M, et al. National Burn Repository 2005: a ten-year review. J Burn Care Res. 2006;27(4):411-436. doi:10.1097/01.BCR.0000226260.17523.22
  2. 2. Chan QE, Barzi F, Cheney L, Harvey JG, Holland AJ. Burn size estimation in children: Still a problem. Emergency Medicine Australasia. November 2011:181-186. doi:10.1111/j.1742-6723.2011.01511.x
  3. 3. Lund C, Browder NC. The estimation of areas of burns. Surg Gynecol Obstet . 1944:79:352–8. https://scholar.google.com/scholar?cluster=4671664022958447735&hl=en&as_sdt=0,5.
  4. 4. Wachtel TL, Berry CC, Wachtel EE, Frank HA. The inter-rater reliability of estimating the size of burns from various burn area chart drawings. Burns. March 2000:156-170. doi:10.1016/s0305-4179(99)00047-9
  5. 5. WALLACE A. The exposure treatment of burns. Lancet. 1951;1(6653):501-504. doi:10.1016/s0140-6736(51)91975-7
  6. 6. Tocco-Tussardi I, Presman B, Huss F. Want Correct Percentage of TBSA Burned? Let a Layman Do the Assessment. J Burn Care Res. 2018;39(2):295-301. doi:10.1097/BCR.0000000000000613
  7. 7. Cheah A, Kangkorn T, Tan E, Loo M, Chong S. The validation study on a three-dimensional burn estimation smart-phone application: accurate, free and fast? Burns Trauma. 2018;6:7. doi:10.1186/s41038-018-0109-0
  8. 8. Moore R, Waheed A, Burns B. statpearls. February 2020. http://www.ncbi.nlm.nih.gov/books/NBK513287/.
  9. 9. Jose RM, Roy DK, Vidyadharan R, Erdmann M. Burns area estimation—an error perpetuated. Burns. August 2004:481-482. doi:10.1016/j.burns.2004.01.019
  10. 10. Kamolz L, Lumenta D, Parvizi D, et al. Smartphones and burn size estimation: “Rapid Burn Assessor”. Ann Burns Fire Disasters. 2014;27(2):101-104. https://www.ncbi.nlm.nih.gov/pubmed/26170784.

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