Hair Mapping |
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| Written by drcole |
| Monday, 30 March 2009 07:58 |
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Page 1 of 7 A Comparison of Caucasian and Korean Hair Density, Follicular Density, and Calculated Density; A Compelling Argument for Individual Follicular Group HarvestingIntroductionNumerous investigators have estimated donor area hair density and follicular density over the years. No published study to date has attempted to objectively quantify the totfal follicular density in the donor area. Numerous individuals have estimated follicular hair density in thfe Korean population, but no one has compared Korean densities with Caucasian densities using similar objective methods to measure these densities. The purpose of this study is to more accurately estimate hair density and follicular density in a finite surface area of the donor region and to compare these results in both Korean and Caucasian populations using the same method of measurement.In addition to estimating the total number of follicular groups in the donor area, this study attempted to define the mean number of hairs per follicular group (calculated density) pre-operatively.1 We also evaluated the mean number of hairs per follicular group extracted by a method of individual follicular group harvesting (IFGH), commonly called follicular unit extraction (FUE), known as the Cole Isolation Technique (CIT) and compared them to the donor area calculated densities that were determined pre-operatively.2,3 The purpose of this later comparison was to determine if there were specific advantages to this method of IFGH harvesting over strip donor harvesting. The results of this objective study showed that Korean follicular density and hair density are higher than previously reported in Asian patients. Caucasian hair density and follicular density are higher than in Korean people, but the difference is not as great as previously reported. Previous studies have shown that IFGH produces more hair per graft than does strip harvesting. This study re-confirms that IFGH does offer an advantage over traditional strip harvesting in that it produces more hair per follicular group and a higher percentage of follicular groups containing multiple hairs the distribution of grafts produced. ObjectiveThe donor area was divided into 14 regions of a specified size using a donor area template shown in Figure 1 (Device4Hair). There were 8 major region and 6 minor regions as depicted in Figure 2. The major regions occupied the superior borders, while the minor regions occupied the inferior borders of the donor template. The intersection between the two borders lies along the occipital notch along a line extending to a point 2 to 3 cm superior to the helix. The 8 major regions correspond to the current location where strip harvesting is traditionally performed. The eight major regions are numbered one through eight with numbers 1, 2, 3, and 4 on the right side of the scalp and regions 5, 6, 7, and 8 on the left side of the scalp. Figure 1. Donor area template showing the size and location of 8 major regions and six minor regions. Figure 2. The location of the 14 regions on the scalp with 8 major regions (number 1 - 8) superiorly and 6 minor regions (number 9 - 14) inferiorly. Follicular density and hair density were measured using a 3.57 mm diameter circle, whose surface area is 10 square millimeters. This was done with a 30X hand held microscope (Radio Shack Cat No 63-851). The number of hairs and the number of follicular groups in 10 square millimeters within each region was noted and recorded in the Donor Area Analysis Sheet (Device4hair) shown in Figure 3. The mean follicular density in square centimeters within each circle was estimated by multiplying the number of follicular groups in the 10 square millimeter circles by 10. The total number of follicular groups within each region was estimated by multiplying the mean follicular density in each region by the surface area of each region. The number of hairs per square centimeter was determined by multiplying the total number of hairs in the 10 square millimeter circles by 10. The estimated total number of follicular groups in the donor area was defined by summing the estimated number of follicular groups in all 14 regions of the donor area. Calculated density has previously been defined as the number of hairs in each follicular group. 1 The calculated density was defined by dividing the total number of hairs in the 10 square millimeter circle by the total number of follicular groups in the 10 square millimeter circle. The calculated density estimates the mean number of hairs per follicular group. The mean calculated density of the entire donor region was obtained by taking the average of all the calculated densities in the 14 regions of the donor area. Figure 3. Donor area analysis sheet |
