Extension ready spinal support systems

A spinal support system, comprising:

• a first rod receptacle for mounting to a pedicle screw, said first rod receptacle having a first side wall that includes a first interior surface and a first exterior surface, said first side wall defining a first pair of diametrically opposed slots that extend axially along said first side wall and are open at a proximal end of said first rod receptacle, said first interior surface defining first interior threads, said first exterior surface defining first exterior threads;
• and
• an extension assembly including a second rod receptacle mounted to a base portion, said second rod receptacle including an internal flange having an interior face and defining an axial thickness, said base portion including a mounting platform and a skirt portion that extends from said mounting platform, said skirt portion including interior threads for mating with said first exterior threads of said first rod receptacle, said second rod receptacle having a second side wall that includes a second interior surface and a second exterior surface, said second side wall defining a second pair of diametrically opposed slots that extend axially along said second side wall and are open at a proximal end of said second rod receptacle, said second interior surface defining second interior threads,
• wherein said extension assembly includes a pivot member that attaches said second rod receptacle to said base portion, said pivot member including a head portion and a shaft portion, said shaft portion including a stop that cooperates with said base portion to define a predetermined axial gap dimension between said head portion and said mounting platform of said base portion, said shaft portion being in fixed relationship with said mounting platform, said head portion of said pivot member being dimensioned to extend over said interior face of said internal flange to couple said second rod receptacle and said base portion, said axial gap being greater than said axial thickness of said internal flange to enable monoaxial rotation of said extension rod receptacle about said pivot head portion.