Assessing the clinical relevance of MRI findings in adult achondroplasia patients with lumbar spinal stenosis.

Abstract

Introduction: Achondroplasia (Ach) is the most common form of dwarfism, and lumbar spinal stenosis (LSS) becomes the primary problem for adult Ach patients.

Research question: This study aims to determine the cutoff values of LSS for surgical decompression.

Material methods: MRIs of adult achondroplasts with symptomatic lumbar spinal stenosis referred to our Medical Centre between 2019 and 2022 were reviewed. The degree of lumbar spinal stenosis was assessed by the Schizas scale and dural sac cross-sectional area (DSCA). Regression analysis was used to evaluate the association between treatment decisions and the degree of stenosis, while receiver operating characteristic (ROC) analysis was performed to identify cutoff values. A follow-up survey was conducted to validate clinical effectiveness.

Results: In total, 68 patients were included (mean age: 46.2 ± 15.4 years; 60 % female). Individuals subjected to decompression had higher Schizas scales (p < 0.001) and smaller DSCA (62.5 ± 34.3 mm² vs 91.0 ± 40.2 mm², p < 0.001). ROC analysis demonstrated that lumbar decompression was indicated at levels with Schizas grade C or D or a DSCA less than 62 mm². Follow-up investigation revealed less favorable clinical outcomes in patients exceeding the severity thresholds of either the Schizas scale or DSCA.

Discussion and conclusion: Schizas scales C and D or DSCA smaller than 62 mm² should alert the surgeons that the non-surgical approach is prone to fail. Furthermore, this threshold also facilitate clinically relevant interpretation of lumbar MRIs by non-specialists in achondroplasia patients.