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

A Prospective Case Series to Evaluate Handling and Feasibility of DensiProbe Spine Assessing Vertebral Bone Strength in Patients Undergoing Transpedicular Fixation of the Spine - a Pilot Study

A new mechanical device was developed in order to provide the surgeon with intraoperative information about the mechanical strength of the cancellous bone within the vertebral body. DensiProbe Spine is intended to be used in patients undergoing transpedicular stabilization of the thoracolumbar spine. The objective of the DensiProbe Spine pilot study is to investigate the handling and feasibility of the DensiProbe Spine measurement device.

Study Overview

• Status: Completed
• Conditions: Spinal Diseases
• Intervention / Treatment: Device: DensiProbe Spine

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 30

Contacts and Locations

Study Locations

• Switzerland
  • BE
    • Bern, BE, Switzerland, 3010
      • Inselspital
    • Bern, BE, Switzerland, 3006
      • Klinik Sonnenhof

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients undergoing transpedicular stabilization of the spine

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Transpedicular stabilization; Patients undergoing transpedicular stabilization of the spine	Device: DensiProbe Spine; Intraoperative DensiProbe Spine measurements

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Surgeon's compliance- and handling-oriented questionnaire	The general satisfaction of the surgeon with DensiProbe Spine as well as specific problems that are likely to occur during the measurement with DensiProbe Spine will be assessed	Baseline
Intra- and post-operative adverse events	All intra- and postoperative adverse events will be assessed and analyzed regarding their relationship to the study device	Up to 2 months postsurgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bone mineral density	The bone mineral density will be measured preoperatively in the lumbar spine (L1-L4) using DXA in order to assess local bone status.	Baseline
Pedicle screw migration	The migration of the pedicle screw will be performed by measuring the angle between the pedicle screw axis and the caudal endplate. The amount of screw migration is defined as the difference in that angle between the baseline (postoperative) and the two month lateral x-rays	2 months postsurgery
QCT analysis of bone biopsies	For each vertebral body under investigation a probe of trabecular bone is obtained to determine bone quality using quantitative micro-CT analysis	Baseline
Application of bone cement	For each patient the surgeon decides whether or not augmentation with bone cement is necessary	Baseline

Collaborators and Investigators

• Sponsor: AO Clinical Investigation and Publishing Documentation
• Collaborators: University Hospital Inselspital, Berne
• Investigators: Principal Investigator: Lorin M Benneker, MD, University Hospital Inselspital, Berne

Study record dates

Study Major Dates

• Study Start: August 1, 2010
• Primary Completion (Actual): March 1, 2012
• Study Completion (Actual): August 1, 2012

Study Registration Dates

• First Submitted: May 18, 2010
• First Submitted That Met QC Criteria: May 18, 2010
• First Posted (Estimate): May 19, 2010

Study Record Updates

• Last Update Posted (Estimate): January 25, 2013
• Last Update Submitted That Met QC Criteria: January 24, 2013
• Last Verified: January 1, 2013

More Information

Terms related to this study

• Keywords: Spinal Diseases; Bone strength; DensiProbe; Transpedicular fixation; Dorsal instrumentation
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Bone Diseases; Spinal Diseases
• Other Study ID Numbers: DensiProbe Spine 2010