Abstract
Follicular Unit Extraction (FUE) is a relatively new hair restoration technique in harvesting hair follicles from the donor area. Patient demand and recognition of this harvesting technique have increased significantly over recent years. The primary reason for FUE’s popularity is the minimally invasive nature of the technique and quick healing of the donor region. FUE also does not result in a donor linear scar normally associated with the strip method. However, the hair physician today often finds it difficult to quantify the hair loss problem of his patient. Technical difficulties associated with the measurement of important characteristics like hair and follicular units density as well as the exact surface size of the recipient area because of the irregular shape and the curvature factor make the problem more complex. In addition, the presence of native hairs within the treated area needs the calculation of hair quantity, in order to estimate the necessary number of hairs/grafts for ...
Follicular Unit Extraction (FUE) is a relatively new hair restoration technique in harvesting hair follicles from the donor area. Patient demand and recognition of this harvesting technique have increased significantly over recent years. The primary reason for FUE’s popularity is the minimally invasive nature of the technique and quick healing of the donor region. FUE also does not result in a donor linear scar normally associated with the strip method. However, the hair physician today often finds it difficult to quantify the hair loss problem of his patient. Technical difficulties associated with the measurement of important characteristics like hair and follicular units density as well as the exact surface size of the recipient area because of the irregular shape and the curvature factor make the problem more complex. In addition, the presence of native hairs within the treated area needs the calculation of hair quantity, in order to estimate the necessary number of hairs/grafts for an optimal aesthetic result. Furthermore, postoperative follow ups are mainly based on a comparison of the before and after patient picture over a period of time. This study involves the application of mathematics and general physics concepts, theories and methods to optimize the FUE technique. It is our earnest desire to explain how the principles of medical physics and methods of mathematical modeling can be applied to reduce the follicular transection rate as well as donor-scalp injury caused by FUE donor harvesting Τo that purpose, a novel integrated system named FOLLYSIS was specifically designed so that includes a fully organized relational database and an image analysis system with statistical inference for FUE hair transplant procedures. Similarly, this system allows for the best and most effective use of the FUE technique by allowing the physician: -To archive patient data.-To use digital trichoscopy.-To design the individual patient treatment planning. -To constantly monitor each patient follow up.-To quantify the patient outcome. FOLLYSIS Design FOLLYSIS design includes the following: Database module: A patient based tree-like database structure was developed with three top-down levels. The top level contains detailed information regarding patient demographics and scalp condition. The next level corresponds to the hair transplant procedure performed on each patient and Information about surgical procedure is recorded. The final level concerns follow-up examinations post-operatively. Image Analysis Module: Contrast enhancement filters were applied to increase the separability of hair follicles compared to the background. Segmentation algorithms were utilized to correctly separate the follicular units from the skin. Using the Delaunay triangulation algorithm, the detected units were connected in order to successfully measure and the mean intra-follicular distance. Furthermore, an automatic hair assignment algorithm was implemented. In this way, parameters such as, a) density of donor and recipient area (follicular units and hairs per square centimeter), b) mean number of hairs per follicular unit, c) the intra-follicular distance, were measured. Additionally, an advanced method for automatic calculation of the recipient area surface from macro-photographs was included taking into consideration the curvature of the area. Specific mathematic formulas were embodied into the system which automatically calculates the number of grafts or hair follicles that should be placed within the recipient area in order to increase the density up to a given level. Statistical Inference Module: The system includes statistical procedures to perform comparisons between the donor and the recipient area calculated parameters. In this way, intra-patient correlations between the image analysis results are extracted to characterize the transplant outcome in a quantitative way.ResultsThe accuracy of the algorithm, was evaluated in 56 micro-photos (Bodelin ProScope HR2 at 640x480 pixels) taken from different patients. The sensitivity of the algorithm in correctly detecting follicular units position was 97.5% (mean) with 3.8 standard deviation. The precision of the algorithm had a mean of 98.6% with 3.1 standard deviation. Pre-operatively, the system helps the physician to precisely calculate both the surface and the grafts needed for an optimal coverage of the recipient area without wasting the donor area. Post-operatively, the hair surgeon is capable of monitoring the procedure outcome by using graphs presenting the increase in density in a time line way. Moreover, the implementation of FOLLYSIS in evaluating the efficacy of a method that reduces the injury to donor area caused by the punch was examined in 35 patients. The use of FOLLYSIS proved to be invaluable in precisely calculating the decrease in skin trauma in Vertical Extraction compare to that in Acute Extraction.ConclusionThe quantification of parameters, which up until now were calculated manually or empirically, are established automatically. By utilizing image processing of micro-photographs of the recipient area, in conjunction with the aforementioned methodology, an invaluable tool can be offered which provides immediate patient data, quantifies the patient outcome and allows the physician to precisely design a hair transplant treatment planning for an optimal aesthetic result. FOLLYSIS seems to be a promising tool for both diagnosis and follow up treatment, by automatically measuring changes in hair density, hair diameter and hair quantity. Ultimately FOLLYSIS enables the physician to correctly evaluate the efficiency of the technique which minimizes the injury to the donor area, allows for an easier and more effective harvesting process and results in FUE optimization.
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