Title:Prediction of Lumbar Pedicle Screw Loosening Using Hounsfield Units in
Computed Tomography
Volume: 20
Author(s): Li Shu, Aikeremujiang Muheremu*, Yuchen Ji, Rui Zhang and Wenge Liu
Affiliation:
- Department of Orthopedics, Sixth Affiliated Hospital of Xinjiang Medical University, Urumqi, 39, Wuxing Nan Rd, Tianshan District, Xinjiang
86830001, P.R. China
Keywords:
Osteoporosis, Spine surgery, Hounsfield unit, Computed tomography, Pedicle screw loosening, Treatment.
Abstract:
Introduction:
One of the most common issues following pedicle screw fixation is pedicle screw loosening. There are, however, few trustworthy methods for
predicting screw loosening. The goal of the current study was to identify an efficient technique for using preoperative CT scanning to predict screw
loosening in older patients and to offer recommendations for preoperative surgical planning.
Methods:
The current analysis included retrospectively all patients who underwent lumbar pedicle screw fixation for degenerative lumbar diseases in our
department between January 2015 and January 2022. Hounsfield units were used to assess each vertebra's attenuation in a CT scan (HU).
Postoperative X-ray testing identified screw loosening. Using IBMSPSS 24.00 software, one-way analysis of variance (ANOVA) and receiver
operating characteristic (ROC) curve analysis were performed.
Results:
Over a mean follow-up period of 28.4±11.5 (range 12-44 months) months, screw loosening was noted in 53 of 242 patients (136 male and 106
female, average age 58.7±7.3 years). Gender, BMI, smoking habits, and whether or not a patient had diabetes or spondylolisthesis were not shown
to be significantly different among the patients (P>0.05). The difference between the average lumbar vertebral HU values in the screw-loosening
group and the control group was significant (P<0.01) at 120.3±31.5HU and 138.6±37.6HU, respectively. The average HU value of L1-L4 exhibited
an area under the curve (AUC) of 0.691 (95% CI: 0.614-0.784), according to ROC curve analysis. A HU cut-off value of 122 HU is a likely cut-off
point to predict screw loosening with a sensitivity of 70% and a specificity of 58%.
Conclusion:
The use of screw augmentation techniques can be decided using a prospective CT scan HU value-based prediction. An independent risk factor for
screw loosening in an instrumented lumbar vertebra is a cutoff L1-L5 average HU value of 122 HU.
