Analgesic effect of epidural anesthesia via the intervertebral foramen approach in percutaneous transforaminal endoscopic discectomy: a retrospective study

BACKGROUND: Satisfactory intraoperative analgesia is critical for percutaneous transforaminal endoscopic discectomy (PTED). Local anesthesia (LA) and epidural anesthesia (EA) are recommended for PTED. LA alone does not achieve satisfactory pain management during PTED and other analgesics or sedatives are usually needed. Traditional EA, which involves implanting an epidural catheter through the midline or paramedian, has disadvantages such as difficulty in catheterization and increased preoperative preparation time. Rather than performing conventional EA, we injected local anesthetics through the intervertebral foramen during the puncture process, which we termed lumbar transforaminal EA (LTEA), and observed its feasibility and safety. This study aimed to conduct a comprehensive comparison of differences in analgesia between LA and LTEA in patients with PTED. METHODS: We performed a retrospective analysis of patients who underwent PTED between January 2018 and January 2021. Patients were divided into LA and LTEA groups. Data obtained from the electronic medical records included primary outcomes (visual analog scale [VAS] scores and anesthesia satisfaction rate) and secondary outcomes, including vital signs such as heart rate (HR), mean arterial pressure (MAP), total dosage of fentanyl, operation time, X-ray exposure time, Oswestry Disability Index (ODI) scores, and complications. RESULTS: In total, 160 patients (80 in each group) were analyzed in this study. The VAS scores for lumbar and leg pain were significantly lower in the LTEA group than in the LA group (P < 0.0001). The anesthesia satisfaction rate was 90.0% in the LTEA group and 72.5% in the LA group (P < 0.005). MAP and HR values in the LTEA group were significantly lower than those in the LA group (P < 0.05). The total dose of fentanyl in the LTEA group was significantly lower than that in the LA group (P < 0.05). As for ODI values, the average operation time, X-ray exposure time, and incidence of complications were not significantly different between the two groups (P > 0.05). CONCLUSIONS: LTEA simplifies the process of EA and can achieve a good analgesic effect intraoperatively without increasing the preoperative preparation time; thus, it may be adopted as an alternative mode of anesthesia during PTED surgery.