Part of the appeal of "limited time offers" at restaurant chains - think McDonald's McRib or Wendy's pretzel bacon cheeseburger - is the items are bound to eventually disappear. But Erik Combs, chef of the Mt. Pleasant-headquartered Wild Wing Café, says the scheme also gives chains an opportunity to assess the popularity of new dishes before adding them to the permanent menu.

Wild Wing's flatbreads evolved from a limited time offer. "We've had them for years now," Combs says.

The flatbreads have been on the menu for so long that they're due for an update. The chain's new menu, rolling out in August, will feature redesigned flatbreads.

"We've designed a completely new style," Combs says. "The whole thing, top to bottom, is changed."

Although Combs refrained from detailing the revamped appetizer's architecture, he says new toppings include cilantro pesto and shrimp with red onions.

Other additions to the new menu include honey lime Sriracha wings and honey lime Sriracha salad dressing. The chain's also planning another limited time offer in June: The "light and fresh" menu emphasizes veggie wraps and salads.

Although Wild Wing will enlist LTOs for full-time duty, Combs says he has no intention of ever formalizing the chain's "secret menu," which other restaurants sometimes use as a tool to cheaply gauge customer interest in an item. At Panera Bread, the Power Chicken Hummus Bowl and the Power Breakfast Egg White Bowl recently made the jump from the "hidden menu" to the posted menu board.

Combs says he doesn't want to interfere with the sense of "involvement" that comes from ordering an off-menu item. According to Combs, the quintessential "secret" item at Wild Wing Café (these secrets typically aren't very closely guarded: In-N-Out Burger publishes its secret menu on its website) is the "buff-ilada," first dreamed up at a Charleston location.

"It's not something we do, mix sauces at random," Combs says of the buffalo sauce blended with spicy ranch. "It's something that guests like to call their own. If someone orders it, you know they're in the know."