An embodiment in accordance with the present invention provides a continuum dexterous manipulator (CDM) with a specially designed flexible tool, to be used as a handheld or robotic steerable device for treatment of hard-tissue-related diseases. The CDM of the present invention works well in treatment of soft and sticky material (similar to a lesion) as well as milling the hard tissues (e.g. sclerotic liner of osteolytic lesions) and bone tumors. The present invention is also directed to flexible drilling tools as well as characterization and evaluation of integrating these tools with the CDM in curved-drilling of hard bone towards treatment of hard tissue related diseases (e.g. osteonecrosis or pelvic fracture). The present invention can also include use of various types of drill geometries, aspiration and irrigation, and endoscope view in curved-drilling and trajectory planning.