In this paper, we present and analyze a novel concept for multidimensional elastic routing based on spatial and spectral optical networking enabled by optical Multiple Input Multiple Output (MIMO) processing and Orthogonal Frequency Division Multiplexing (OFDM). These two techniques, complemented with dynamic adaptive coded-modulation are shown to form the three cornerstones of the multidimensional elastic routing concept, such that they can perform key functionality currently performed by optical crossconnects and/or Layer 2 optical switches. A statistical throughput analysis which relates key spatial and spectral components (e.g. aggregation overhead, spatial inputs/outputs, and number of spectral superbands), and identifies important practical scenarios is performed. Moreover, a performance evaluation of a flexible rate-adaptive Low Density Parity Check (LDPC)-based coded modulation scheme for multidimensional elastic networking is presented, revealing considerable gains compared to legacy approaches. By thus exploiting spatial and spectral domains in optical fiber to enable flexible routing and switching, the new scheme is promising for next-generation elastic optical networks.