An expandable spinal fixation system comprising: - an expandable barrel assembly including an upper barrel half and a lower barrel half such that lower barrel half is vertically adjustably connected to upper barrel half: - the upper barrel half having: an upper barrel proximal end; and an upper barrel distal end, distal from the proximal end; and including a vertical plate arranged for engaging an upper spinous process; - the lower barrel half having: a lower barrel proximal end; and a lower barrel distal end, distal from the lower barrel proximal end; and including a vertical plate arranged for engaging a lower spinous process; - a fixed barrel assembly having a body sized to fit between the upper barrel half and the lower barrel half in one of a posterior-to-anterior direction and a lateral direction, - a first planar arm extending between the upper barrel proximal end and upper barrel distal end, - a second planar arm extending between lower barrel proximal end and lower barrel distal end, characterized in that the system further comprises - a gusset extending upwardly from the first planar arm and connecting to the vertical plate, providing structural stability between the first planar arm and the vertical plate, and a gusset extending downwardly from the second planar arm and connecting to the vertical plate, providing structural stability between the second planar arm and the vertical plate, and - the expandable spinal fixation system, further comprising a ratchet assembly connecting the upper barrel half to the lower barrel half such that the ratchet assembly provides for relative vertical movement of the upper barrel half with respect to the lower barrel half. - an expandable barrel assembly including an upper barrel half and a lower barrel half such that lower barrel half is vertically adjustably connected to upper barrel half: - the upper barrel half having: an upper barrel proximal end; and an upper barrel distal end, distal from the proximal end; and including a vertical plate arranged for engaging an upper spinous process; an upper barrel proximal end; and an upper barrel distal end, distal from the proximal end; and including a vertical plate arranged for engaging an upper spinous process; - the lower barrel half having: a lower barrel proximal end; and a lower barrel distal end, distal from the lower barrel proximal end; and including a vertical plate arranged for engaging a lower spinous process; a lower barrel proximal end; and a lower barrel distal end, distal from the lower barrel proximal end; and including a vertical plate arranged for engaging a lower spinous process; - a fixed barrel assembly having a body sized to fit between the upper barrel half and the lower barrel half in one of a posterior-to-anterior direction and a lateral direction, - a first planar arm extending between the upper barrel proximal end and upper barrel distal end, - a second planar arm extending between lower barrel proximal end and lower barrel distal end, characterized in that the system further comprises - a gusset extending upwardly from the first planar arm and connecting to the vertical plate, providing structural stability between the first planar arm and the vertical plate, and a gusset extending downwardly from the second planar arm and connecting to the vertical plate, providing structural stability between the second planar arm and the vertical plate, and - the expandable spinal fixation system, further comprising a ratchet assembly connecting the upper barrel half to the lower barrel half such that the ratchet assembly provides for relative vertical movement of the upper barrel half with respect to the lower barrel half.