surface may be movable or installable to provide at least temporary access to the interior volume 110 referring now to fig7 10 an exemplary embodiment comprises a multi piece fusion member 200 in this embodiment fusion member 200 comprises four separate components that can be assembled to form a unit that functions similar to previously described fusion member 100 fusion member 200 comprises a first clamping member 201 a second clamping member 202 a first plate 203 and a second plate 204 first plate 203 comprises a plurality of tabs 223 and second plate 204 comprises a plurality of tabs 233 when deformed tabs 223 and 233 are configured to extend through slots 224 in first and second clamping members 201 and 202 respectively and engage spinous processes 310 and 320 shown in fig9 and 10 this configuration allows for first and second plates 203 204 to remain coupled to first and second clamping members 201 and 202 first and second plates 203 204 and first and second clamping members 201 and 202 may also comprise coupling or receiving members not shown including without limitation threaded members pins eyelets etc first clamping member 201 comprises a first end 216 and second clamping member comprises a second end 218 first end 216 second end 218 and the central portions of first plate 203 and second plate 204 combine to form a cage 215 defining an inner volume 210 second plate 204 comprises a lower surface 229 clearly.