The Association Between Hounsfield Units and Mechanical Failure in ASD Patients

Area of Science:

• Orthopedics
• Radiology
• Spine Surgery

Background:

• Low bone mineral density (BMD) is a risk factor for revision surgery in adult spinal deformity (ASD).
• Hounsfield units (HUs) on CT scans are proposed as a proxy for BMD assessment.
• Predicting mechanical failure in ASD surgery is crucial for patient outcomes.

Purpose of the Study:

• To evaluate Hounsfield units (HUs) in the lumbar spine.
• To determine the association between lumbar HUs and mechanical failure after ASD surgery.

Main Methods:

• Retrospective cohort study of 170 ASD patients (2010-2020) with ≥2-year follow-up.
• Preoperative CT scans were used to measure Hounsfield units (HUs) in the lumbar spine (L1-L5).
• Mechanical failure was defined as proximal junctional failure, pseudarthrosis, or implant failure requiring revision.

Main Results:

• Mechanical failure occurred in 27% of patients within 2 years.
• Mean lumbar HUs were similar between patients with (146±51) and without (135±52) mechanical failure (P=.232).
• Hounsfield units demonstrated low discriminatory power (AUC=0.58) for predicting mechanical failure.

Conclusions:

• No significant association was found between lumbar Hounsfield units and mechanical failure in ASD patients.
• Hounsfield units on preoperative CT scans are not recommended for predicting mechanical failure in this population.
• Further research may explore other imaging biomarkers for predicting surgical complications in ASD.