-osis. 1  1 suffix meaning a (specified) action, process, or result: homeosis, narcosis, zygosis. 2  2 suffix meaning increase in a pathological condition: calcicosis, psittacosis, varicosis. -osis. , pl. Combining form meaning a process, condition, or state, usually abnormal or diseased; production of an abnormal substance, increase of a normal substance, or parasitic infestation.
If non-surgical treatment fails to relieve the symptoms of accessory navicular syndrome, surgery may be appropriate. Surgery may involve removing the accessory bone, reshaping the area, and repairing the posterior tibial tendon to improve its function. This extra bone is not needed for normal foot function.
B, Dissection of same accessory bone (small dot) indicating division of main portion of the tibialis posterior tendon and the accessory bone located in the inferior portion and separated from the tuberosity of the navicular (large dot) by a central cavity (probe).