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Johnson et al. Art Int Surg 2024;4:401-10 https://dx.doi.org/10.20517/ais.2024.40 Page 407

Figure 3. Posterior superficial adipose tissue appears to be important for the 3D-CNN model to classify pseudarthrosis. 3D-CNN:
Three-dimensional convolutional neural network.

pseudarthrosis predilection, not captured by demographic variables, as opposed to a local tissue
abnormality at the future site of pseudarthrosis.

Overall, this work serves as an augmentation to existing models to preoperatively predict pseudarthrosis .
[17]
Previously identified risk factors to predict pseudarthrosis include alcoholism, smoking, fusion location,
vertebral bone quality score, diabetes, sarcopenia, advanced age, and potentially graft material [1,23-26] . Not all
of these factors were readily available in our dataset. However, it is notable that our demographic analysis of
available metrics did not reveal any significant differences between pseudarthrosis and non-pseudarthrosis
cohorts except for age. Thus, by incorporating raw MRI, one can leverage high-dimensional data that are
often readily available in clinical databases with minimal manual extraction required. With the
incorporation of readily available imaging, this technique does not rely on meticulous database mining and
is free from the problems of patient bias when reporting metrics such as alcohol use and smoking status.
Furthermore, this work provides potential insight into the biological underpinnings of pseudarthrosis
development and could serve as background evidence for future studies exploring the role of global adipose
tissue characteristics in those who develop pseudarthrosis.

It is well-documented that posterior musculature and sarcopenia appear to be strongly correlated with
mechanical complications following ASD surgery . Thus, it is notable that the current work, and our past
[27]
work using similar techniques to predict PJK using MRI have both revealed imaging risk factors of soft
tissue - adipose tissue and posterior musculature, respectively. This contributes to the growing body of
literature focusing on soft tissue characteristics as driving factors for mechanical complications, as opposed
to bony anatomy. The authors do not discount the importance of bone integrity for consideration of ASD
surgery, but rather aim to outline the additional importance of soft tissue health when considering a large
deformity operation.