An anchor assembly, comprising: an anchoring member comprising a body portion having a first end and a second end opposite the first end, the anchoring member defining a longitudinal lumen in the body portion extending from the first end to the second end and configured and arranged to slidably receive a portion of an electrode assembly, wherein the anchoring member further comprises two opposing wing members (545, 550) extending from the body portion, each of the wing members defining a through hole (547, 552); and a shell assembly comprising first and second mating shell portions (590, 580) configured and arranged to be disposed on opposites sides of the anchoring member and to be coupled together to anchor the portion of the electrode assembly within the anchoring member, each of the first and second mating shell portions comprising a center portion (600, 595) and two lateral portions (602, 603, 596, 597) extending from the center portion, wherein the center portion fits over the anchoring member with the lateral portions of the first and second mating shell portions opposite each other, wherein the lateral portions of the first mating shell portion each have a prong member (605, 608) and the lateral portions of the second mating shell portion each have an aperture (598, 599), wherein the prong members and apertures are configured and arranged for mating to form a locking arrangement, wherein the shell assembly is configured and arranged so that the prong members (605, 508) of the lateral portions of the first mating portion pass through the through holes (547, 552) of the two opposing wing members (545, 550) when the shell assembly is disposed on opposite sides of the anchoring member and the first and second mating portions are mated. an anchoring member comprising a body portion having a first end and a second end opposite the first end, the anchoring member defining a longitudinal lumen in the body portion extending from the first end to the second end and configured and arranged to slidably receive a portion of an electrode assembly, wherein the anchoring member further comprises two opposing wing members (545, 550) extending from the body portion, each of the wing members defining a through hole (547, 552); and a shell assembly comprising first and second mating shell portions (590, 580) configured and arranged to be disposed on opposites sides of the anchoring member and to be coupled together to anchor the portion of the electrode assembly within the anchoring member, each of the first and second mating shell portions comprising a center portion (600, 595) and two lateral portions (602, 603, 596, 597) extending from the center portion, wherein the center portion fits over the anchoring member with the lateral portions of the first and second mating shell portions opposite each other, wherein the lateral portions of the first mating shell portion each have a prong member (605, 608) and the lateral portions of the second mating shell portion each have an aperture (598, 599), wherein the prong members and apertures are configured and arranged for mating to form a locking arrangement, wherein the shell assembly is configured and arranged so that the prong members (605, 508) of the lateral portions of the first mating portion pass through the through holes (547, 552) of the two opposing wing members (545, 550) when the shell assembly is disposed on opposite sides of the anchoring member and the first and second mating portions are mated.