New patient related factors to predict difficult lumbar punctures

This study aimed to determine the factors associated with lumbar puncture failure and its duration. A total of 262 patients who were eligible for spinal anesthesia were recruited for this analytical observational study. Spinal anesthesia was conducted in a sitting position between the 4th and 5th lumbar vertebrae with a 25-gauge Quincke needle with a midline approach. The first primary outcome was lumbar puncture failure on the first try (yes or no). The second main outcome was the duration of the lumbar puncture procedure in seconds. Multivariable logistic and linear regression models were used to determine the factors associated with lumbar puncture failure and duration of lumbar puncture, respectively. The mean (SD) patients age was 38.9 (19.3) years, and 76.7% of the patients were male. The mean (SD) frequency of needling was 2.0 (1.5), and the mean (SD) of length of lumbar puncture procedure was 36.8 (40.7) seconds. The results of the multivariable logistic regression model showed that the non-palpability of sacral cornua (aOR: 6.67; P- value < 0.001) and sacrococcygeal protuberance visibility (aOR: 5.35; P- value < 0.001) had a significant association with lumbar puncture failure at the first try. The results of the multivariable linear regression model indicated that BMI (aβ: 7.44; P- value: < 0.001), the distance between sacral cornua and skin in horizontal sonographic view (aβ: 56.27; P- value < 0.001), and non-palpability of sacral cornua (aβ: 53.24; P- value: 0.003) were significantly associated with the duration of lumbar puncture procedure. The results of the present study indicated the factors associated with difficulty in lumbar puncture. These factors could be beneficial in spinal anesthesia management as they could be used as practical pre-anesthesia assessment tools to predict possible challenges in spinal anesthesia.