Introduction: Although scalp reduction procedures constitute a reliable and effective means for the surgical management of MPB of the vertex area of selected patients, some questions are still unsolved and some points might be improved. Objective: The aims of the present study were: to quantitatively evaluate the effects of undermining and galeotomies as regarding to scalp reduction procedures; to test the ex vivo biomechanical properties of acutely expanded scalp flaps in order to quantitatively assess the efficacy of acute scalp expansion; to describe an operative technique, based on the use of three anchoring galeal flaps, aimed at reducing the percentage of “stretch back” that occurs after performing scalp reduction procedures. Methods: Regarding the biomechanical properties of the scalp, data were collected by stepwise loading 20 scalp flaps, obtained by a reversed-Y incision down to and through the galea aponeurotica, together with 1, 5, and 15 cm undermining, on the subgaleal layer, along both sides of the sagittal scalp incision, as well as before and after performing three full-thickness galeotomies lengthwise and parallel to the sagittal scalp incision. Regarding the ex vivo study, we used a total of 14 fresh male cadavers: In each cadaver, a rectangular (4 cm x 10 cm), laterally-based flap was designed on each side of the scalp, starting from the superior margin of the external auditory canal. One randomly-selected flap per each scalp underwent acute-intermittent expansion (3-minute expansion 3-minute rest cycle per three times with the maximal expansion achievable), while the contralateral flap served as control. After the expansion process, the acutely-expanded flaps were measured to assess if the applied biomechanical stress have determined any changes in their dimensions. The biomechanical properties of both expanded and control flaps were then assessed by means of a dynamometer and a force-transducer. The new operative technique, based on the use of galeal flaps, has been tested in 12 male patients undergoing a midline scalp reduction procedure: in each patient, three rectangular galeal flaps, in direct continuity with the longitudinal margin of the left scalp flap, were sutured individually to the galeal under surface of the right scalp flap to draw the two flaps toward the midline of the scalp and to relieve the wound margins of closing tension. Tattoo marks were placed on the patient's scalp at the level of two vertical lines drawn through the external auditory meatuses (A1-A2) and 6 cm posterior (B1-B2) to measure the movements and the stretching of scalp during a 3-month post-operative period. Mean stretch-back at both levels was compared with that obtained from a control group of 13 male patients who underwent the same surgical procedure but without the use of the anchoring galeal flaps. Results: The obtained data confirmed the value of undermining to diminish the tension on wound margins when closing a scalp defect. There was a progressive decrease in tension required to advance the wound edge when the amount of undermining was sequentially increased. Most of this reduction occurred with the 5-cm undermining, although statistically the 15-cm undermining also resulted in a significant decrease in the tension required to close the defect. In the closing-tension interval 500 gf to 1500 gf, the mean gain of length of the flap per galeotomy was 1.67 mm, while we observed a mean 40% reduction of the closing tension after the galeotomies. Regarding the quantitative effects of intraoperative scalp expansion, the obtained data showed that the biomechanical benefits provided by acute scalp expansion were not statistically different (p<0.05) from those obtained by simple subgaleal undermining. The use of the described galeal flaps allowed us to obtain an 80.93 percent and an 88.09 percent stretch-back reduction at levels A1-A2 and B1-B2, respectively, indicating a positive cost/benefit ratio. Conclusions: In our opinion, the reported data might be of some utility in striving to enhance the results obtainable with scalp reduction procedures.
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