Devices, tools and methods for minimally invasive implantation and distraction between spinous processes for treatment of spinous disorders. An interspinous implant device for distracting at least one pair of adjacent spinous processes includes a main body (12) including a shaft (14) having a longitudinal axis; and first and second arms (18) extending transversely from the main body, wherein at least one of the first and second arms is slidably mounted with respect to the shaft. The arms are configured and dimensioned to extend laterally from both sides of the spinous processes when implanted therebetween and to be inserted between the spinous processes laterally from a single side thereof. The arms are variably positionable between a closed configuration, to facilitate insertion of the arms between the adjacent spinous processes, and an open configuration, in which the arms are separated from one another.