Patient- and Operator-Related Factors Associated With Difficult Lumbar Epidural Catheter Placement

Background

Lumbar epidural catheter placement is widely used for perioperative analgesia in lower abdominal, pelvic, and lower extremity surgery; however, the procedure may be technically challenging and may require multiple skin punctures. In this study, we defined difficult placement as requiring two or more skin punctures and aimed to identify patient- and operator-related factors associated with difficult lumbar epidural catheter placement.

Methods

In this retrospective observational study, we analyzed consecutive patients who underwent lower abdominal, pelvic, or lower extremity surgery under general or spinal anesthesia combined with lumbar epidural anesthesia. Difficult lumbar epidural catheter placement was defined as requiring two or more skin punctures. Patient- and operator-related factors associated with difficult placement were evaluated using multivariable logistic regression analysis. The multivariable model included age, body mass index (BMI), and years of anesthesiology experience. To account for within-operator correlation arising from multiple procedures performed by the same operator, cluster-robust standard errors were calculated using the individual operator as the clustering unit.

Results

Of 111 consecutive patients who underwent lumbar epidural catheter placement between April 8, 2021, and July 31, 2026, two were excluded because of insufficient documentation, leaving 109 patients for analysis. Difficult placement occurred in 31 (28.4%) patients. In the multivariable logistic regression analysis, older age was independently associated with difficult placement (adjusted odds ratio, 1.03 per year; 95% confidence interval, 1.002-1.058; p=0.037). In contrast, BMI (adjusted odds ratio, 1.06 per kg/m²; 95% confidence interval, 0.980-1.142; p=0.151) and years of anesthesiology experience (adjusted odds ratio, 0.99 per year; 95% confidence interval, 0.945-1.042; p=0.763) were not independently associated with difficult placement. In the univariate analysis, BMI and puncture approach were significantly associated with difficult placement. Difficult placement was also associated with longer procedure time and greater skin-to-epidural space distance. Lumbar puncture level was not significantly associated with difficult placement.

Conclusions

Older age was independently associated with difficult lumbar epidural catheter placement. In contrast, no significant associations were observed for BMI or years of anesthesiology experience. However, the magnitude of the association between age and difficult placement was modest, and the clinical significance and predictive utility of age remain uncertain. The paramedian approach was more frequently used in patients with difficult placement; however, this association may have been influenced by the selection of the puncture approach according to anticipated procedural difficulty.