Pilot Study to Evaluate Feasibility of DensiProbe Spine Assessing Bone Strength in Spinal Surgery

Osteoporotic fragility fractures often occur in the spine. A common surgical technique is the transpedicular fixation using pedicle screws. A major complication of this treatment is a cut-out or back-out of the screw due to insufficient anchorage of the implant in the vertebral body.

A new mechanical device was developed in order to provide the surgeon with intraoperative information about the mechanical strength of the cancellous bone. In cases of low bone quality, the treatment can be adapted to the patient's condition, for example by augmentation of the screw anchorage using bone cement. However, this treatment involves a risk of cement leakage and subsequent pulmonary embolism or nerve damage. Furthermore, cement augmentation is time-consuming. Therefore, there is a need for a diagnostic device that can intraoperatively support the surgeon's decision on the appropriate treatment.

DensiProbe Spine was developed accordingly to the clinically approved DensiProbe Hip, which was designed for the same diagnostic reasons in patients with hip fractures undergoing fracture fixation with the dynamic hip screw (DHS). However, the application of bone strength measurements in the spine is in so far different to the hip as the anatomical dimensions in the spine are much smaller and lower values of bone mineral density (BMD) and bone strength are expected.

The objective of this pilot study is to investigate the handling and feasibility of the newly developed DensiProbe Spine measurement device. In case of a positive result of the pilot study, a multicenter cohort study will be performed in order to clinically validate the DensiProbe Spine device by assessing the correlation between DensiProbe Spine measurements and the amounts of pedicle screw migration in patients undergoing transpedicular fixation.

Inclusion criteria

• Age 18 or older
• Indication for transpedicular fixation of the thoracolumbar spine
• Ability to understand and read local language at an elementary level
• Signed informed consent by patient or legal guardian to participate in the study according to the protocol

Exclusion criteria

• Patients who are legally incompetent
• Scoliosis (Cobb angle on AP radiograph > 10°)
• Benign or malign vertebral bone tumour
• Active malignancy
• Infection diseases, eg. hepatitis, human immunodeficiency virus (HIV)
• Pre-drilling with power-drill
• Life-threatening condition
• Drug or alcohol abuse
• Participation in any other medical device or drug study that could influence the results of the present study