Local and Regional Anaesthesia
Background and Goal: Low back pain is often reported after epidural anaesthesia. Needle trauma is thought to be one of the suggested mechanisms (1), however there are studies that disagree (2). The effect of the size of the epidural needle on the incidence of low back pain in ambulatory patients was evaluated.
Material and Methods: We studied 372 ambulatory patients ASA I-II, aged 22-70 years old undergoing lumbar epidural anaesthesia (levobupivacaine 0.5%). Patients were assigned randomly to one of the two following groups: group-16 (n = 185) and group-18 (n = 187) in which epidural needle Tuohy 16G and 18G was used respectively. Epidural puncture was performed by median approach (lateral position, L4/5 or L3/4 interspace). Standard monitoring was used. All patients were mobilised 6-7 hrs after operation. We recorded the number of epidural puncture attempts and the occurrence and duration of backache in the patients. All patients were followed up for one month. In the case of backache mild analgesics and NSAID's were prescribed together with rest. Statistical analysis was achieved by using chi-square test and ANOVA-one way. Significant difference accounted for p < 0.05.
Results and Discussion: Both groups were comparable. There was no difference in the number of epidural attempts in the total number of patients (group-16: 2 ± 0.7, group-18: 1.7 ± 0.6). The incidence of low back pain was significantly higher (p < 0.05) in group-16 (12%) versus group-18 (4.5%). The number of epidural attempts in patients suffering from backache didn't differ between the two groups (group-16: 2.25 ± 1, group-18: 2 ± 1). The back pain appeared between 2nd and 5th day after the epidural technique and its duration was higher in group-16 (10.5 ± 3 days) than in group-18 (8 ± 2 days), difference 18% (p < 0.05).
Conclusions: From the above results we conclude that the size of the epidural needle plays an important role in the percentage and duration of back pain possibly due to the more intense trauma caused by it.
1 Gentili ME. Cah Anesthesiol. 1994;42:247-255
2 Chan ST. Med J Malaysia. 1995;50:241-245