Izikulufu ezihlanganisiwe ziyisici sokuxhuma esihlukile somshini esebenzisa inhlanganisela ehlakaniphile yezikulufu nama-spacers ukuze kuzuzwe uxhumano oluqine kakhulu noluthembekile. Lo mklamo wenza isikulufu silungele izinhlelo zokusebenza ezidinga ukuvalwa okwengeziwe noma ukumuncwa ukushaqeka.
Ku-screws ehlanganisiwe, ingxenye ehlanganisiwe ye-screw ihlanganiswe ne-spacer, engakwazi ukunikeza amandla okuxhumana okuhle kuphela, kodwa futhi ivimbele ngokuphumelelayo ukukhulula nokuwa. Ngesikhathi esifanayo, ukuba khona kwe-spacer kunikeza ukugcwaliswa kwegebe nokuvalwa kwendawo yokuxhuma, okuthuthukisa ngokwengeziwe ukusetshenziswa kwesikulufu.