Assessment of Bone Material Strength by Microindentation in vivo in Patients with Acromegaly

Bone mass is an important determinant of bone fragility, but the strength and
integrity of the skeleton also depends on other properties of bone tissue,
collectively termed bone quality. We have showed recently that in a
well-defined cohort of acromegaly patients the prevalence of vertebral
fractures is very high, despite long-term biochemical control of GH excess and
normal mean bone mineral density. In addition, 20% of patients showed
progression of vertebral fractures during long-term control. BMD measurements
are not a good predictor of fracture risk in this patient group. We postulate
that this apparent high vertebral fracture risk is due to alterations in bone
quality rather than changes in bone mass. To date there is no standard method
to assess the mechanical competence of bone in humans in vivo. The Universities
of California and Barcelona have jointly developed a novel, minimally invasive
technique that can specifically measure the micro hardness of bone tissu. This
technique, named microindentation, generates information on bone tissue
properties that which are not captured by BMD measurements. This technique is
fully operational in our department (in a clinical research setting)

To assess Bone Material Strength (BMS) in patients with acromegaly with
fractures and without fractures.

prospective study, case-control

Except for the additional measurement of microindentation, all laboratory and
radiological investigations are part of the routine evaluation of patients at
the outpatient clinic. The time required for the BMT measurement is 10 minutes.
The procedure is performed under local anesthesia and is associated with
minimal discomfort for the patient.