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 including a shaft having a longitudinal axis; and first and second parallel arms extending transversely from the main body, wherein at least one of the first and second parallel arms is slidably mounted with respect to the shaft. The parallel 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 parallel arms are variably positionable between a closed configuration, in which the parallel arms are positioned close to or in contact with one another, to facilitate insertion of the parallel arms between the adjacent spinous processes, and an open configuration, in which the parallel arms are separated from one another.