A medical device having a flexible shaft is provided, the flexible shaft including an active deflection section. The medical device also includes at least one control wire passing through at least a portion of the flexible shaft such that actuation of the at least one control wire causes deflection of the active deflection section of the flexible shaft. At least one control wire guide is provided which surrounds the at least one control wire along at least a portion of a length thereof. The at least one control wire guide is formed from a superelastic metal alloy and is configured as a helical spring.