Hand surface area as a percentage of body surface area in Asian children: a pilot study

The hand surface area (HSA) of one hand has been estimated as 1% of the body surface area (BSA). This does change with the patient's age, gender, and body mass index (BMI). There are many HSA studies done on adult populations, but fewer done on children. Our hypothesis in this study is that the general HSA equation for Caucasian adults cannot be applied as accurately to children and Asian people. HSA was defined as the area of the palm without fingers in this study. Children are in a stage of growth. If a child's hand growth ratio is not the same as that of an adult, the result of HSA/BSA calculation could be different. We undertook this study to determine whether or not there were any differences in HSA/BSA among Korean children (7-18 years) and adults (20-60 years), and compared our results with western data. A total of 186 boys aged between 7 and 18 years, were recruited for this study; their HSA was measured, directly. A total of 186 adults aged between 20 and 60 years were selected as well. BSA was calculated only for volunteers in subjects who HSA had been measured. From these results, HSA/BSA was calculated. HSA/BSA ratio of Korean boys was 0.69 ± 0.05%, which was less than 1%. It is suggested that the ratio of the western data may not be applicable to Asian children, particularly, Korean children. HSA/BSA ratio can be applied in administration of drug doses and estimation of the area of burns.     

Gentamicin-PMMA beads. Pharmacokinetic and nephrotoxicological study

Five patients treated with gentamicin-polymethylmethacrylate (PMMA) beads were monitored during the treatment of nine to 14 days. Kinetic data of the gentamicin delivery were gathered constantly by multiple samples of blood and urine. The treatment with 48-360 beads caused a gentamicin serum concentration of 0.03-0.4 micrograms/ml and a renal excretion rate of 3-40 micrograms/min. The total amount of gentamicin excreted after the whole treatment was 20%-70%, with an in vivo half-life of 5.7-10 days. The gentamicin appeared to be released constantly during the entire treatment (nine to 14 days); the beads are kinetically slow release carriers. Despite precise measurement of tubular and glomerular renal function, no nephrotoxicity could be demonstrated. This local antibiotic gentamicin therapy may use the blood bone barrier effectively as a protection of the body against a very high local gentamicin concentration.     

Remodeling markers are associated with larger intracortical surface area but smaller trabecular surface area: a twin study

All postmenopausal women become estrogen deficient but not all remodel their skeleton rapidly or lose bone rapidly. As remodeling requires a surface to be initiated upon, we hypothesized that a volume of mineralized bone assembled with a larger internal surface area is more accessible to being remodeled, and so decayed, after menopause. We measured intracortical, endocortical and trabecular bone surface area and microarchitecture of the distal tibia and distal radius in 185 healthy female twin pairs aged 40 to 61 years using high-resolution peripheral quantitative computed tomography (HR-pQCT). We used generalized estimation equations to analyze (i) the trait differences across menopause, (ii) the relationship between remodeling markers and bone surface areas, and (iii) robust regression to estimate associations between within-pair differences. Relative to premenopausal women, postmenopausal women had higher remodeling markers, larger intracortical and endocortical bone surface area, higher intracortical porosity, smaller trabecular bone surface area and fewer trabeculae at both sites (all p<0.01). Postmenopausal women had greater deficits in cortical than trabecular bone mass at the distal tibia (-0.98 vs. -0.12 SD, p<0.001), but similar deficits at the distal radius (-0.45 vs. -0.39 SD, p=0.79). A 1 SD higher tibia intracortical bone surface area was associated with 0.22-0.29 SD higher remodeling markers, about half the 0.53-0.67 SD increment in remodeling markers across menopause (all p<0.001). A 1 SD higher porosity was associated with 0.20-0.30 SD higher remodeling markers. A 1 SD lower trabecular bone surface area was associated with 0.15-0.18 SD higher remodeling markers (all p<0.01). Within-pair differences in intracortical and endocortical bone surface areas at both sites and porosity at the distal tibia were associated with within-pair differences in some remodeling markers (p=0.05 to 0.09). We infer intracortical remodeling may be self perpetuating by creating intracortical porosity and so more bone surface for remodeling to occur upon, while remodeling upon the trabecular bone surface is self limiting because it removes trabeculae with their surface.     

Side-to-side earlobe variations with respect to surface area and shape: A quantitative study

Side-to-side earlobe variations, based on the size of the earlobe surface area and a classification into earlobe types, were quantitatively analyzed in 58 female students, ranging from 20 to 22 years old. Using a new earlobe measurement technique, a closed-circuit outline of each ear was directly traced onto a clear polyethylene sheet, after which the surface area of the earlobe portion of each ear was identified, measured by a digital planimeter, and analyzed. Results revealed that side-to-side differences in the size of the earlobe surface area existed in all subjects. In contrast, based on classifying the earlobe shape into three types (i.e., tapering, square, or pendulous), differences in the mean earlobe surface area value among the three types were not significant. However, when the classification of the earlobe shape was reduced to only two types (pendulous or nonpendulous), the mean earlobe surface area value between the two types was highly significant. These results thus suggest that for a quantitative analysis of earlobe variations, classification of the earlobe shape into two types rather than into three types is the better method. This method makes it easy to distinguish earlobe differences. Further, if the earlobe differences are noted before ear piercing, a balanced ear piercing effect can be achieved.     

Predictors of body surface area.

STUDY OBJECTIVE: To determine the accuracy of body surface area (BSA) calculations proposed in the literature and their applicability to patient populations such as neonates and parturients. DESIGN: Using 395 actual BSA measurements in the literature, 15 prediction formulas were assessed for accuracy using the root mean squared error (RMSE) method of prediction. Height/weight distributions of infants and parturients, and the relationship of DuBois and DuBois predictions to actual BSA, were compared using scatter plots. Percentage errors across different body sizes were determined. SETTING: Obstetrics clinic and labor and delivery rooms at the University of Chicago Medical Center. PATIENTS: Sixty women (gestational week 34 to 40) and 148 neonates. MEASUREMENTS AND MAIN RESULTS: We measured the height and weight of the neonates and the women. We also used the height, weight, and BSA of 395 subjects reported in the literature. Although the commonly used DuBois and DuBois formula was derived from only 10 subjects, our statistical analysis demonstrates that it can be used over a wide range of measured BSAs (RMSE = 6.3%) and patients, including both infants and pregnant women. As BSA increases, so does the absolute prediction error, but the percentage error is greatest for infants, for whom the formula tends to underestimate BSA. There were no other significant differences in predictive accuracy for gender, age, or body habitus. CONCLUSIONS: Several BSA formulas, including the DuBois and DuBois formulas adequately predict measured BSA over a wide range of patient populations. Although the original subjects studied by Dubois and DuBois excluded extremes of height and weight, their formula appears to be a valid predictor.     

Determination of hand surface area as a percentage of body surface area by 3D anthropometry

This study investigates the hand surface area (HSA) and palm surface area (PSA) percentages of body surface area (BSA). The HSA and PSA of 135 men and 135 women were measured by scanner and incorporated into an existing BSA database to derive %HSA/BSA and %PSA/BSA using five stature heights and three body weights in accordance with population distribution. Allowing for various degrees of specificity, the mean %HSA/BSA and mean %PSA/BSA were found to be 2.29% (0.24%) and 0.89% (0.09%), respectively. Gender and body weight group were significant factors.     

Human body surface area database and estimation formula

This study established human body surface area (BSA) database and estimation formula based on three-dimensional (3D) scanned data. For each gender, 135 subjects were drawn. The sampling was stratified in five stature heights and three body weights according to a previous survey. The 3D body surface shape was measured using an innovated 3D body scanner and a high resolution hand/foot scanner, the total body surface area (BSA) and segmental body surface area (SBSA) were computed based on the summation of every tiny triangular area of triangular meshes of the scanned surface; and the accuracy of BSA measurement is below 1%. The results of BSA and sixteen SBSAs were tabulated in fifteen strata for the Male, the Female and the Total (two genders combined). The %SBSA data was also used to revise new Lund and Browder Charts. The comparison of BSA shows that the BSA of this study is comparable with the Du Bois and Du Bois’ but smaller than that of Tikuisis et al. The difference might be attributed to body size difference between the samples. The comparison of SBSA shows that the differences of SBSA between this study and the Lund and Browder Chart range between 0.00% and 2.30%. A new BSA estimation formula, BSA = 71.3989 × H^.7437 × W^.4040, was obtained. An accuracy test showed that this formula has smaller estimation error than that of the Du Bois and Du Bois’; and significantly better than other BSA estimation formulae.     

Internal surface area and other measurements in emphysema

Some measurements of emphysema were made on 29 pairs of non-emphysematous lungs and 44 pairs of emphysematous lungs inflated at a standard transpulmonary pressure of 25 cm. of formalin. These were: a subjective visual assessment (units); an assessment of the volume of the lung parenchyma involved by emphysema (point count); an average subjective visual grading by eight pathologists (Co-op score); mean linear intercept or average distance between alveolar walls at a transpulmonary pressure of 25 cm. of formalin (Lm); mean linear intercept corrected to total lung capacity (Lm_C); internal (alveolar) surface area at 25 cm. transpulmonary pressure (ISA); internal surface area at total lung capacity (ISA_C); internal surface area corrected to an arbitrary lung volume of 5 litres (ISA₅). Internal surface area measurements were generally decreased in severe emphysema. Because of the wide range of ISA and ISA_C in non-emphysematous lungs, most emphysematous lungs fell within the normal range. The range of ISA₅ was smaller in non-emphysematous lungs and most emphysematous lungs fell outside this range. ISA₅ in `mild' emphysema was not distinguishable from non-emphysematous lungs. Most emphysematous lungs in which the surface area was decreased less than expected from subjective assessment were examples of centrilobular emphysema. Lm and Lm<sub>C</sub> were increased in emphysema. ISA<sub>5</sub>, Lm, and Lm<sub>C</sub> paralleled the subjective assessments of emphysema rather better than ISA or ISA<sub>C</sub>, even when the latter were expressed as a percentage of predicted. Lm and Lm<sub>C</sub> in lungs with mild emphysema fell within the ranges found in non-emphysematous lungs, but the mean value of Lm in lungs with `mild' emphysema was different from the mean Lm of non-emphysematous lungs, at conventional levels of significance. Since objective methods did not recognize adequately examples of `mild' emphysema, a subjective visual grading system (with its limitations) may have a definite place.     

Individual variation of cortical surface area asymmetries

Asymmetries in the size of cortical regions are regularly associated with functional lateralization. Assessment of cortical asymmetry is often confounded by measurement artifact and a lack of information about the normal variance of asymmetry in regions that are functionally symmetric. In order to measure hemispheric asymmetries in the surface area of cortical gyri, magnetic resonance (MR) images were acquired from 10 normal, right-handed males. Computer representations of the cortical surface in all 20 hemispheres were reconstructed from the images by first creating a white matter model and then 'inflating' it to approximate the cortical surface. The advantage of this approach is that it accurately models the deep sulci as well as the cortical surface. Surface area measurements of the whole hemisphere, the postcentral and the cingulate gyrus were collected from each subject. For each region an asymmetry score was computed based on the difference in the surface area of the left and right regions. Many subjects showed asymmetries in these two gyri; however, the mean asymmetry scores were never significantly asymmetric. The large variability of individual asymmetry scores indicates that cortical asymmetries may be present even in the absence of clear functional asymmetry. An understanding of the degree of asymmetry in structures that do not show clear functional lateralization is critical for interpreting data gathered from cortical regions that are functionally asymmetric.      

Management of burns of over 80% of total body surface area: a comparative study

The aim of this retrospective, comparative study was to analyse the management of extensive burns so as to decrease morbidity and mortality. Over 1987-1996, 24 people with burns >80% of total body surface area and >50% full-thickness burn were admitted to the burn unit of Anhui Medical University Hospital (group A); 30 similar admissions over 1997-2006 formed group B. No significant difference was found in age, male:female ratio, % total body surface or full-thickness burn area between the two groups. Severe shock developed in 19/24 cases in group A and 23/30 cases in group B, following inadequate fluid resuscitation, although group B received a higher mean resuscitation fluid volume during the first 24h after burn. Early excision and grafting was performed for 8/24 people in group A and 23/30 in group B. Inhalation injury was seen in 18/24 cases in group A and 28/30 cases in group B. Prophylactic tracheotomy was undergone by 8/24 casualties in group A and 22/30 in group B. Mortality in group A was significantly higher than in group B (95.8% vs. 63.3%, p<0.05) and survival was longer in group B. These results showed that refinements in burn shock resuscitation, and advances in early wound excision, skin grafting and respiratory management were associated with decreased morbidity and mortality after severe burn.     

Failure of a knee prosthesis accelerated by shedding of beads from the porous metal surface

A 61-year-old man who received a porous-metal-coated knee implant returned eight months later with chronic synovitis, instability, and loosening of his artificial joint. Subsequently, metal beads were detected in the joint space and soft tissues and were also embedded in the articulating surface of the tibial component. There was scoring of the tibial surface, and polyethylene wear particles were noted in the synovial and fibroconnective-tissue membranes, which had formed beneath the tibial component. Many particles were seen inside giant cells and macrophages. Failure in this case was probably accelerated by the granulomatous response in the soft tissue to wear particles. There was osteolysis rather than new bone growth at the interface with the tibial component. Analysis indicated that poor bead-bonding strength may have initiated the problem. Careful appraisal of the outcome from use of beaded porous-metal-coated devices and assurance of their adequate bonding strength are essential for further progress.     

In vivo study of biodegradable alginate antibiotic beads in rabbits.

The authors investigated the lyophilized poly-L-lysine-coated alginate antibiotic delivery system in vivo for the treatment of musculoskeletal infections. The sodium alginate was mixed with vancomycin, coated with poly-L-lysine and lyophilized to form 3 mm in diameter biodegradable antibiotic beads. The antibiotic beads were implanted in the distal femoral cavities of rabbits for in vivo investigation. The local concentration of vancomycin was well above the minimal inhibitory concentration of Staphylococcus aureus for 21 days. The release was most marked during the first two days. The diameters of sample inhibition zone ranged from 8 to 16 mm, the relative activity of vancomycin ranged from 12.5% to 100%. The blood level of vancomycin reached its peak (46.0 mg/l) two days after implantation and fell to 3.2 mg/l at two weeks. It was undetectable after three weeks. There was no increase in the concentration of blood urea nitrogen and serum creatinine after the implantation. Histological observations showed that bead materials were biodegradable, resorbed slowly and only cause mild host reaction. This study offers a biodegradable delivery system of antibiotics to treat musculoskeletal infections.     

Determination of hand and palm area as a ratio of body surface area in Indian population

Background:

Accurate estimation of body surface area (BSA) burn is important. In small and patchy burns, the patient''s hand is used to estimate percentage of burn which is traditionally considered as 1%. There is discrepancy about what percentage of TBSA is constituted by the palm and hand. Therefore, this study was designed to determine correctly the TBSA represented by the palmar surface of the entire hand and palm in the Indian population.

Material and Methods:

300 healthy adult (male and female) and 300 healthy children (male and female) were included in the study. TBSA was calculated using DuBois formula and hand and palm surface area was calculated using hand tracing on plain paper. The hand/palm percentage of BSA (ratio) was determined by dividing hand/palm surface area by total BSA.

Results:

The mean hand and palm ratio for adults was 0.92% and 0.50%, respectively. The mean hand and palm ratio in children was 1.06% and 0.632%, respectively.

Conclusion:

The hand area (palm plus digits) is more closely represented to 1% of TBSA in Indian population.