The Principles of Scalp Extension

Abstract

This article is written to help the reader understand the physical principles behind scalp extension. A review of the history and physiology of scalp extension is first discussed. The newest form of scalp extension is then reviewed and a series of equations developed by the author are analyzed to help the reader understand what is really occurring with the latest twist on extension (i.e. burying a stretched silicone sheet to each opposing galeal surface). When scalp extension is applied to circumferential scalp reduction, the primary advantage is a reduction in the time interval between surgeries from 3 months to 1 month. When scalp extension is applied to midline scalp reduction, the primary advantages are an elimination of stretch-back and a decreased time interval between surgeries. Because circumferential scalp reduction does not normally incur stretch-back, the surgeon performing midline scalp reduction will perceive a much greater improvement in overall cosmesis from extension because the elimination of a previous loss (50% stretch-back) will be perceived as a gain postoperatively.