Intraoperative Surgeon Assessment of Bone: Correlation to Bone Mineral Density, CT Hounsfield units and Vertebral Bone Quality

James T Bernatz; Brian C Goh; Jonathan D Skjaerlund; Anthony L Mikula; Sarah E Johnson; Mohamad Bydon; Jeremy Fogelson; Benjamin Elder; Paul Huddleston; Mohammed Karim; Ahmad Nassr; Arjun Sebastian; Brett Freedman

doi:10.1097/BRS.0000000000004854

Intraoperative Surgeon Assessment of Bone: Correlation to Bone Mineral Density, CT Hounsfield units and Vertebral Bone Quality

Spine (Phila Pa 1976). 2023 Oct 19. doi: 10.1097/BRS.0000000000004854. Online ahead of print.

Affiliations

¹ Department of Orthopedic Surgery Mayo Clinic 200 1st St SW Rochester, MN 55905-0002.
² Department of Neurologic Surgery Mayo Clinic 200 1st St SW Rochester, MN 55905-0002.

PMID: 37855301
DOI: 10.1097/BRS.0000000000004854

Abstract

Study design: Retrospective observational study of consecutive patients.

Objective: The purpose of the study is to determine if a surgeon's qualitative assessment of bone intraoperatively correlates with radiologic parameters of bone strength.

Summary of background data: Preoperative radiologic assessment of bone can include modalities such as CT Hounsfield Units (HUs), dual-energy x-ray absorptiometry bone mineral density (DXA BMD) with trabecular bone score (TBS) and MRI vertebral bone quality (VBQ). Quantitative analysis of bone with screw insertional torque and pull-out strength measurement has been performed in cadaveric models and has been correlated to these radiologic parameters. However, these quantitative measurements are not routinely available for use in surgery. Surgeons anecdotally judge bone strength, but the fidelity of the intraoperative judgement has not been investigated.

Methods: All adult patients undergoing instrumented posterior thoracolumbar spine fusion by one of seven surgeons at a single center over a 3-month period were included. Surgeons evaluated the strength of bone based on intraoperative feedback and graded each patient's bone on a 5-point Likert scale. Two independent reviewers measured preoperative CT HUs and MRI VBQ. BMD, lowest T-score and TBS were extracted from DXA within 2 years of surgery.

Results: Eighty-nine patients were enrolled and 16, 28, 31, 13 and 1 patients had Likert grade 1 (strongest bone), 2, 3, 4, and 5 (weakest bone), respectively. The surgeon assessment of bone correlated with VBQ (τ=0.15, P=0.07), CT HU (τ=-0.31, P<0.01), lowest DXA T-score (τ=-0.47, P<0.01), and TBS (τ=-0.23, P=0.06).

Conclusion: Spine surgeons' qualitative intraoperative assessment of bone correlates with preoperative radiologic parameters, particularly in posterior thoracolumbar surgeries. This information is valuable to surgeons as this supports the idea that decisions based on feel in surgery have statistical foundation.