A connector assembly includes an elongated connector housing having a first end, a second end, and a length, the 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 lead lumen that extends from the port into the connector housing； connector contacts axially spaced-apart and disposed along the lead lumen for coupling to terminals along a proximal end of a lead or lead extension； and non-conductive spacers disposed between adjacent connector contacts. Each of the spacers includes a first radial sidewall, a second radial sidewall, and an intermediate region extending between, and connecting, the first and second radial sidewalls. The first and second radial sidewalls and intermediate region define boundaries of an open circumferential space opposite the lead lumen with respect to the intermediate region.
