First webspace deepening: comparing the four-flap and five-flap Z-plasty. Which gives the most gain?

A two-part investigation was undertaken to determine whether a four- or a five-flap Z-plasty gives the greatest increase in length (deepening) over the same radius of a web. In part A, flaps were designed on a model of a webspace made from a plastic frame and Speedo fabric; four types of flaps, three different central limb lengths, and three trials for each length gave a total of 36 observations. In part B, flaps were designed on the natural axillary webs of the pig; three Yorkshire pigs with one type of flap per axillary web gave a total of 12 observations. In part A, the stereometric elongation (percent deepening) produced by the five-flap Z-plasty was similar to that of a single 60-degree Z-plasty (4-cm central limb; five-flap versus a single Z procedure, 72.5+/-4.3 versus 75.0+/-2.5 percent). The 90-degree four-flap procedure gave a 1.59 times greater deepening than the five-flap procedure (4-cm central limb; 90-degree four flap technique, 114.2+/-1.4 percent). The 120-degree four-flap technique gave 2.0 and 1.26 times greater deepening than the five-flap and 90-degree four-flap procedures, respectively (4-cm central limb; 120-degree four-flap technique, 144.2+/-1.4 percent). In part B, the 90-degree four-flap Z-plasty again produced a significantly greater lengthening (1.57 times) than the five-flap procedure (132.7+/-6.4 versus 84.0+/-4.0 percent; p<0.05), and the percentage of elongation of the 120-degree four-flap procedure was 1.27 times greater than that of the 90-degree four-flap technique (167.3+/-7.0 versus 131.3+/-2.3 percent; p < 0.05). In conclusion, the four-flap Z-plasty produced greater webspace deepening than that of the five-flap Z-plasty. The 120-degree four-flap procedure gave the greatest percentage of elongation, but it was more difficult to design and close than the 90-degree four-flap Z-plasty.