Traditional medium access control (MAC) protocols utilize temporal mechanisms such as access probability or backoff interval adaptation for contention resolution. Temporal contention resolution aims to separate transmissions from different nodes in time to achieve successful transmissions. We explore an alternative approach for wireless networks - named "spatial backoff" - that adapts the "space" occupied by the transmissions. By adapting the space occupied by transmissions, the set of "locally" competing nodes, and thus, the channel contention level, can be adjusted to reach a suitable level. There are different ways to realize spatial backoff. In this paper, we propose a dynamic spatial backoff algorithm using the joint control of carrier sense threshold and transmission rate. Our results suggest that spatial backoff is promising to improve the channel utilization.