Preoperative coronal magnetic resonance imaging: a critical evaluation of the Kambin's triangle for the transforaminal lumbar interbody fusion procedure.

Abstract

Prospective cohort study. To evaluate the accuracy and reliability of coronal versus axial magnetic resonance imaging (MRI) measurements of Kambin's triangle, using intraoperative findings as the reference standard, in transforaminal lumbar interbody fusion (TLIF). Previous studies on large cages or extreme TLIF have proposed methods, using axial view MRI, for preoperative measurement of Kambin's triangle. However, the accuracy and reliability of these methods have not been evaluated, which can be particularly challenging in cases of severe stenosis. A prospective study was conducted in patients undergoing TLIF surgery. Demographic data and surgical approach details were collected. Coronal and axial MRI measurements of the width of Kambin's triangle were obtained at the upper and lower endplates on the operative side. Intraoperative measurements of the corridor were obtained. The relationship between MRI measurements and these intraoperative measurements was analyzed. Among 60 patients, coronal MRI measurement of the width of Kambin̓s triangle at both endplates demonstrated a strong correlation with intraoperative distances. In contrast, axial MRI showed a weak correlation at the upper endplate and a moderate correlation for the lower endplate. The mean absolute error was significantly lower with coronal MRI compared to axial MRI for both the upper (0.70±0.61 mm vs. 2.69±2.90 mm, p<0.001) and lower endplates (1.00±0.98 mm vs. 5.53±4.58 mm, p<0.001). Inter- and intra-observer reliability were also higher for coronal MRI. The study result indicates that coronal MRI measurements of Kambin's triangle are more accurate and reliable than axial measurements. The high reliability of coronal MRI for preoperative assessments in patients undergoing TLIF facilitates improved surgical planning and more appropriate interbody selection.