The Collaborative International Dictionary of English v.0.48:

Torsional \Tor"sion*al\, a.
   Of or pertaining to torsion; resulting from torsion, or the
   force with which a thread or wire returns to a state of rest
   after having been twisted round its axis; as, torsional
   force.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "torsional":
   ambagious, anfractuous, circuitous, circumlocutory, contortional,
   contortive, convolutional, distortive, flexuose, flexuous,
   involute, involuted, involutional, labyrinthine, mazy, meandering,
   meandrous, rivose, rivulose, roundabout, ruffled, serpentine,
   sinuate, sinuose, sinuous, snaky, tortile, tortuous, turning,
   twisting, twisty, whorled, winding, wreathlike, wreathy