Outcome of transforaminal epidural steroid injection for lumbar radiculopathy: initial three-year experience at Upendra Devkota Memorial-National Institute of Neurological and Allied Sciences, Nepal

BACKGROUND: The prevalence of low back pain with radiculopathy in general population varies from 9.9% to 25%, which can be due to bony narrowing of the lateral recess or due to prolapsed intervertebral disc. Transforaminal epidural injection of a mixture of long-acting anaesthetic (bupivacaine) and particulate steroids (depomedrol) has been a treatment modality in patients not responding to initial physiotherapy and neuropathic pain medications. METHODS: To analyze the effectiveness of transforaminal epidural steroid injection (TFESI) in the treatment of low back pain with radiculopathy, a retrospective case series evaluating the records of patients that received TFESI (1 mL 0.5% bupivacaine +1 ml/40 mg depomedrol) under C-arm guidance from January 2015 to December 2018 (3 years) at Upendra Devkota Memorial-National Institute of Neurological and Allied Sciences (UDM-NINAS), their lumbo-sacral MRI and the pre-procedure, 1-week and 3-month numeric pain rating scale, were analyzed. Successful treatment (reduction of pain scale by more than 50% of baseline at 3 months) in the patients with bony recess stenosis and those with prolapsed intervertebral disc was compared. RESULTS: Out of 67 patients that received TFESI, 35 (52.23%) could be followed up. The mean age was 55.8 ± 14.39 years and 51.3% were females. 68.57% had L5 and 20% had S1 radiculopathy. Bony recess stenosis was seen in the aged 40% and PIVD was the cause of radiculopathy in 60%. The median duration of radicular pain prior to intervention was 3 months. TFESI was effective as the mean numeric pain scale before injection was 8.97 ± 1.32 which reduced to 3.91 ± 3.23 (paired t test p value < 0.001) at 1 week post injection and 3.23 ± 3.34 (paired t test p value < 0.001) at 3 months post injection. Twenty-six of the 35 patients (75.29%) had more than 50% pain relief compared to baseline at 3 months and were satisfied. Nine patients continued to have pain; however, only one required a surgical intervention. The effectiveness of TFESI was not significantly different in different ages (Fisher’s exact test p value 0.182) and in different anatomic levels (Fisher’s exact test p value 0.241). Six out of eight patients with bony recess stenosis benefited as compared to 14 out of 19 patients with PIVD, though it was not statistically significant (Fischer’s exact test p value 0.688). There were no adverse events recorded. CONCLUSION: TFESI is a safe and efficacious treatment modality in patients with radicular low back pain especially in aged patients in whom surgery under general anaesthesia is not free from risk.