A connector assembly includes an elongated connector housing defining a port at the second end of the connector housing for receiving a proximal end of a lead or lead extension； a lumen that extends from the port along at least a portion of the length of the connector housing； connector contacts axially spaced-apart and disposed along the lumen； and non-conductive spacers disposed between adjacent connector contacts, at least one of the non-conductive spacers includes a first region. One or more additional features are included to resist bending of the connector assembly. One such feature is a non-conductive first insert disposed between adjacent connector contacts to maintains a minimum distance between the adjacent connector contacts. Another feature is a stiffening element disposed within apertures in the spacers and connecting two or more of the spacers. Yet another feature is a stiffening sleeve disposed within the housing,
