An implantable medical device (IMD) including an elongated housing and a tine housing configured to attach to the elongated housing. The tine housing may support an extending plurality of tines and a distal-most electrode. An inner chamber is bounded at least in part by the elongated housing and the tine housing with an adhesive fill port in fluid communication with the inner chamber. A method of assembling the IMD includes forming the inner chamber and substantially filling the inner chamber with an adhesive through the adhesive fill port. The method may include curing the filling adhesive.