Table 1.
Summary of randomized controlled trials for evaluating the efficacy of transforaminal nerve root injections.
| Study | Study Design | Participants | Interventions | Outcome Measurement | Summary of Outcomes |
|---|---|---|---|---|---|
| Devulder et al., 1999 [89] | Randomized controlled trial | n = 60 (three treatment groups with 20 participants each) | Group I with 1 mL bupivacaine 0.5% combined with 1500 units hyaluronidase and 1 mL saline per nerve root sleeve. Group II with 1 mL bupivacaine 0.5% combined with 40 mg methylprednisolone solution per nerve root. Group III with bupivacaine 0.5% combined with 1500 units hyaluronidase and 40 mg methylprednisolone solution. |
Verbal pain rating scale at 1, 3, and 6 months | Three treatment methods provided pain relief at the 1-month follow-up, but these effects diminished during the 3- and 6-month follow-ups. Ultimately, none of the three injected solutions demonstrated satisfactory outcome in terms of pain relief. |
| Karppinen et al., 2001 [94] | Randomized controlled trial | n = 160 (two treatment groups with 80 participants each) | Group I: periradicular infiltration with Methylprednisolone-Bupivacaine. Group II: periradicular infiltration with saline. |
VAS and Nottingham health profile at 2 weeks, and 1, 3, 6, and 12 months | At the 2-week follow-up, the steroid injection exhibited superior recovery in terms of leg pain, straight leg raising, lumbar flexion, and patient satisfaction. However, the saline infiltration was significantly lower in back pain at 3 and 6 months, as well as lower in leg pain at 6 months. The combination of methylprednisolone and bupivacaine appeared to have a positive short-term effect. However, at 3 and 6 months, the steroid injection showed a “rebound” phenomenon. |
| Bonetti et al., 2005 [85] | Randomized controlled trial | n = 306 (80 in group I, 86 in group II, 70 group III, 70 in group IV) | Group I, including patients with disc disease: 2 mL steroid injection. Group II, including patients with disc disease: infiltration of 3 mL O(2)-O(3) gas mixture. Group III, including patients without disc disease: 2 mL steroid injection. Group IV, including patients without disc disease: infiltration of 3 mL O(2)-O(3) gas mixture. |
Modified version of the McNab method at 1 week, and 3 and 6 months | Both treatment methods demonstrated excellent pain reduction effects throughout all follow-up periods, regardless of the presence or absence of disc disease, with the most favorable outcomes observed in the short-term follow-up. The O(2)-O(3) gas mixture provided significantly greater pain relief compared to steroid injections, making it a potential first-line alternative to epidural steroids. |
| Ackerman et al., 2007 [84] | Randomized controlled trial | n = 90 (three treatment groups with 30 participants each) | Group I: lumbar epidural steroid injection using caudal approach with 3 mL of isohexol 300 and 4 mL of preservative-free saline with 40 mg of triamincolone. Group II: lumbar epidural steroid injection using interlaminar approach with 3 mL of isohexol 300 and 19 mL of preservative-free saline with 40 mg of triamcinolone. Group III: lumbar epidural steroid injection using transforaminal approach with 3 mL of isohexol 300 and 40 mg of triamcinolone in 4 mL of preservative-free saline. |
VAS at 12 and 24 weeks | During the evaluation period, a significantly higher number of patients who underwent the transforaminal approach reported overall or partial pain relief. The transforaminal route for epidural steroid placement was found to be more effective than the caudal or interlaminar routes. |
| Jeong et al., 2007 [92] | Randomized controlled trial | n = 239 (112 in group I, 127 in group II) | Group I with transforaminal epidural steroid injection using a preganglionic approach. Group II with transforaminal epidural steroid injection using a ganglionic approach. |
VAS at 1 and 6 months | In the short-term follow-up, the preganglionic group exhibited superior treatment outcomes compared to the ganglionic group. No significant difference was identified at the medium-term follow-up. These findings suggest that utilizing transforaminal epidural steroid injection with a preganglionic approach is more effective than a ganglionic approach in the short term, and it demonstrates comparable effectiveness to the ganglionic approach in the medium term. |
| Tafazal et al., 2009 [100] | Randomized controlled trial | n = 150 (76 in group I, 74 in group II) | Group I: local anesthetic injection with 2 mL of 0.25% bupivacaine, Group II: peri-radicular infiltration of corticosteroids with 2 mL of 0.25% bupivacaine and 40 mg of methylprednisolone. |
VAS and ODI at 6 and 12 weeks, and 12 months | After a 3-month follow-up, there were no statistically significant distinctions in pain relief and functional improvement between the two treatment approaches. Similarly, at a minimum of 1 year following the injection, no variation was observed in the necessity for subsequent interventions between the two methods. The peri-radicular infiltration of corticosteroids for sciatica does not confer any additional advantages when compared to the administration of local anesthetic injection alone. |
| Ghahreman et al., 2010 [90] |
Randomized controlled trial | n = 150 (28 in group I, 27 in group II, 37 in group III, 28 in group IV, 30 in group V) | Group I: transforaminal steroid injection with 0.75 mL of 0.5% bupivacaine followed by 1.75 mL of triamcinolone in a concentration of 40 mg/mL. Group II: transforaminal injection of local anesthetic with 2 mL of 0.5% bupivacaine. Group III: transforaminal injection of 2 mL normal saline. Group IV: intramuscular steroid injection with 1.75 mL of triamcinolone (40 mg/mL). Group V: intramuscular normal saline injection with 1.75 mL of triamcinolone (40 mg/mL). |
NRS at 3, 6, and 12 months | A notable increase in the number of patients experiencing pain relief was observed with transforaminal injection of steroids compared to those who received transforaminal injection of local anesthetic or saline, intramuscular steroids, or intramuscular saline. However, it is important to note that the proportion of patients with sustained pain relief decreases over time, and only a few patients maintain relief beyond 12 months. The transforaminal injection of steroids is considered to be effective for pain relief in a subset of patients. |
| Rados et al., 2011 [99] | Randomized controlled trial | n = 64 (32 in group I, 32 in group II) | Group I with transforaminal epidural steroid injection of 40 mg methylprednisolone, 3 mL of 0.5% lidocaine. Group II with interlaminar epidural steroid injection of 80 mg of methylprednisolone mixed with 8 mL of 0.5% lidocaine. |
VAS and ODI at 3 and 6 months | During the 6-month follow-up period, the outcomes of pain relief and functional improvement were positive for both transforaminal and interlaminar epidural steroid injections. When using the transforaminal approach, it provided slightly better long-term pain relief and functional improvement. However, there was no statistically significant difference between the two treatment methods. |
| Cohen et al., 2012 [86] | Randomized controlled trial | n = 84 (30 in group I, 28 in group II, 26 in group III) | Group I with saline. Group II with corticosteroid. Group III with etanercept. |
NRS and ODI at 1, 3, and 6 months | After one month of treatment, overall positive effects were reported, and epidural steroid therapy showed greater efficacy in functional improvement and pain reduction compared to saline or etanercept treatment. Epidural steroid injections have the advantage of providing short-term pain relief for patients with lumbosacral radiculopathy. |
| Ghai et al., 2014 [91] | Randomized controlled trial | n = 62 (32 in group I, 30 in group II) | Group I with fluoroscopically guided epidural injection of methylprednisolone (80 mg) through parasagittal interlaminar approach. Group II with fluoroscopically guided epidural injection of methylprednisolone (80 mg) through transforaminal approach. |
VAS and ODI at 2 weeks, and 1, 2, 3, 6, 9, and 12 months | Significant pain relief and function improvement were observed at all time points post-intervention compared to baseline in both groups. The parasagittal interlaminar and transforaminal approach for low back pain yield similar pain relief and functional improvement. The parasagittal interlaminar approach can be considered as a suitable alternative, for equivalent efficiency, better safety profile, and technical ease, to the transforaminal approach. |
| Kennedy et al., 2014 [95] | Randomized controlled trial | n = 78 (41 in group I, 37 in group II) | Group I with dexamethasone. Group II with triamcinolone. |
NRS and ODI at 2 weeks, and 3 and 6 months | Both triamcinolone and dexamethasone demonstrated significant improvements in pain and function at 2 weeks, 3 months, and 6 months, with no distinct disparities between the two treatments. Dexamethasone seems to be equally effective as triamcinolone in managing the condition. |
| Manchikanti et al., 2014 [97] | Randomized controlled trial | n = 120 (two treatment groups with 60 participants each) | Group I with 1.5 mL of 1% preservative-free lidocaine, followed by 0.5 mL of sodium chloride solution. Group II with 1% lidocaine, followed by 3 mg, or 0.5 mL of betamethasone. |
NRS and ODI at 3, 6, 12, 18, and 24 months | The two-year follow-up results of local anesthesia alone or in combination with steroid therapy are positive. Both local anesthesia with or without steroids in epidural injections can be effective treatments for patients with disc herniation or radiculopathy. These findings indicate that the superiority of steroids over local anesthesia is insufficient in the two-year follow-up survey. |
| Denis et al., 2015 [88] | Randomized controlled trial | n = 56 (29 in group I, 27 in group II) | Group I with lumbar transforaminal injection of dexamethasone 7.5 mg, Group II with lumbar transforaminal injection of betamethasone 6.0 mg, |
VAS and ODI at 1, 3, and 6 months | At 3 months, there was no significant difference between the two treatments in terms of pain relief and functional improvement. However, at 6 months, the dexamethasone treatment showed better effects in terms of functional improvement. |
| Kamble et al., 2016 [93] | Randomized controlled trial | n = 90 (three treatment groups with 30 participants each) | Group I with transforaminal steroid injection. Group II with caudal steroid injection. Group III with epidural steroid. |
VAS and ODI at 1, 6, and 12 months | The transforaminal route showed greater improvements in pain relief and functional improvement compared to the interlaminar and caudal routes. However, there was no significant difference between the interlaminar and caudal routes. Overall, the transforaminal steroid injection group demonstrated better symptomatic improvement in both the short and long term compared to the interlaminar and caudal steroid injection groups. |
| Pandey, 2016 [98] | Randomized controlled trial | n = 140 (82 in group I, 40 in group II, 18 in group III) | Group I with injection by caudal route. Group II with injection by transforaminal route. Group III with injection by interlaminar route. |
JOA at 6 and 12 months | After 12 months of administering steroid injections, all three routes showed effectiveness in improving the JOA score. However, the transforaminal route was significantly more effective than the caudal and interlaminar routes at both 6 and 12 months after the injection. There was no significant difference observed between the caudal and interlaminar routes in terms of their effectiveness. |
| Makkar et al., 2019 [96] | Randomized controlled trial | n = 61 (21 in group I, 20 in group II, 20 in group III) | Group I with epidural steroid injection using midline interlaminar approach. Group II with epidural steroid injection using parasagittal interlaminar approach. Group III with epidural steroid injection using transforaminal approach. |
VAS and ODI at 2 and 4 weeks, and 3 and 6 months | The parasagittal interlaminar approach and transforaminal approach had significantly higher rates of effective pain relief compared to the midline interlaminar approach at 3 and 6 months. ODI scores were significantly lower in the parasagittal interlaminar approach and transforaminal approach compared to the midline interlaminar approach, but there was no significant difference between parasagittal interlaminar approach and transforaminal approach. |
| De et al., 2020 [87] | Randomized controlled trial | n = 50 (two treatment groups with 25 participants each) | Group I with transforaminal epidural local anesthetic injection of 1 mL 0.5% bupivacaine. Group II with transforaminal epidural injection of 1 mL 0.5% bupivacaine with 3 cycles of pulsed radiofrequency of the dorsal root ganglion for 180 s. |
VAS and ODI at 2 weeks and 1, 2, 3, and 6 months | The lumbar pulsed radiofrequency group showed statistically significant reductions in both pain and functional improvement compared to the transforaminal epidural local anesthetic injection group from 2 weeks to 6 months. The application of pulsed radiofrequency to the DRG for an extended period provides long-term pain relief and improves the functional quality of life in patients with chronic lower back pain. |
| Wei et al., 2020 [101] | Randomized controlled trial | n = 90 (three treatment groups with 30 participants each) | Group I with TNF-α inhibitor. Group II with steroids. Group III with lidocaine-only. |
VAS and modified ODI at 6 months | The TNF-α inhibitor showed significantly greater pain relief and improvement in movement function compared to steroids and lidocaine. There was no significant difference between the effects of steroids and lidocaine. |
VAS, visual analog scale; ODI, Oswestry disability index; JOA, Japanese Orthopaedic Association scale; NRS, numeric rating scale.