[Preliminary study on the learning curve of ultrasonic measurement of lumbar spinous process distance change rate]

To analyze the learning curve associated with ultrasound measurement of the change rate of lumbar spinous process distance in patients with lumbar disc herniation.

A retrospective analysis was conducted on 90 patients with lumbar disc herniation who underwent ultrasound measurement of the change rate of lumbar spinous process distance from October 2018 to October 2020. Patients were sequentially numbered from 1 to 90 according to their visit order. All ultrasound measurements were performed by the same physician. Examination time was recorded for each patient. The cumulative sum analysis (CUSUM) method was used to plot the learning curve scatter diagram, which was then fitted with a polynomial function to calculate the inflection point (turning point) of the curve. Based on this turning point, patients were divided into a learning exploration group and a learning stability group. Intergroup comparisons of various indicators were performed to verify the existence of the learning curve.

(1)The best-fit simulation function for the learning curve was Y=8.75+1.86X-0.05X²+0.000 3X³(R²=0.951, P<0.05), with the turning point identified at the 27th case. (2)There were no statistically significant differences between the learning exploration group and the learning stability group regarding age, sex, body mass index (BMI), disease duration, Oswestry disability index(ODI) scores, or the change rate of lumbar spinous process distance(P>0.05). However, the mean examination time was significantly longer in the learning exploration group(3.88±1.30) min compared to the learning stability group(2.21±0.32) min(P<0.05).

Ultrasound measurement of the change rate of lumbar spinous process distance exhibits a distinct learning curve. The turning point occurs at the 27th case. Once the stable phase is reached, the average examination time stabilizes at approximately (2.21±0.32) min.