Table 3.

Summary of studies for evaluating the efficacy of percutaneous epidural neuroplasty.

Study	Study Design	Participants	Interventions	Outcome Measurement	Summary of Outcomes
Gerdesmeyer et al., 2013 [120]	Randomized controlled trial	n = 90 (44 in group I and 46 in group II)	Group I: The caudal approach involved the intentional insertion of a needle and catheter without penetrating the spinal canal. The catheter was placed into the subcutaneous tissue above the affected area, and for three days, 10 mL of preservative-free sodium chloride solution was administered through the catheter before its removal. Group II: The Tun-L catheter was positioned through the sacral canal with injection of 10 mL of contrast. Local anesthetic, 10 mL, 0.25% bupivacaine was administered through the catheter, followed by 10 mL of preservative-free sodium chloride solution infused with 150 units per mL of hyaluronidase. Slow injections of sodium chloride solution, 10 mL, 10%, containing 40 mg of triamcinolone, along with 2 mL of 0.25% bupivacaine. On the 2nd and 3rd days, 10 mL of 0.25% bupivacaine was injected through the catheter, followed by slow injection of 10 mL of 10% sodium chloride solution and 2 mL, 0.25% bupivacaine.	VAS and ODI at 3, 6, and 12 months	In the lysis group, pain relief and functional improvement were significantly greater at 3, 6, and 12 months compared to the placebo group. The minimally invasive percutaneous adhesiolysis procedure could be considered as the first treatment option for patients with chronic lumbosacral radicular pain.
Ji et al., 2015 [116]	Retrospective	n = 363	Catheterization was performed with a caudal approach. After final positioning of the Racz catheter, 6 mL of 0.2% preservative free ropivacaine containing 1500 units of hyaluronidase and 4 mL of 40% triamcinolone acetate was injected. An hour later, 6 mL of 8% sodium chloride solution was infused over 30 min in the recovery room while being monitored.	VAS and Odom’s criteria at 3, 6, 12, and 24 months	Percutaneous epidural neuroplasty proves to be an effective intervention for managing lumbar disc herniation at a single level without affecting the dural sac cross-sectional area.
Moon et al., 2017 [121]	Retrospective	n = 407	The percutaneous epidural adhesiolysis was performed using an RK needle and Racz catheter through the caudal approach. Following the accurate placement of the catheter in the anterior epidural space at the target site, a test dose of 3–5 mL of 1% lidocaine was administered. Subsequently, 10 mL of 0.9% sodium chloride solution was injected, followed by a mixture of 0.125% bupivacaine and 5 mg of dexamethasone. After 5 min, under real-time fluoroscopic guidance, 10 mL of 10% sodium chloride solution was slowly injected.	NRS and GPES at 1 and 12 months	After 12 months of percutaneous epidural adhesiolysis, a highly effective pain reduction was observed in 72.2% of patients. Those who experienced pain relief reported a high level of treatment satisfaction.
Cho et al., 2019 [113]	Retrospective	n = 430	The treatment involved percutaneous adhesiolysis or neuroplasty through a caudal approach, with catheter placement ventrally and laterally. After ensuring proper catheter positioning, and contrast injection, a mixture of 6 mL of 0.2% preservative-free ropivacaine with 1500 units of hyaluronidase and 4 mL of betamethasone sodium phosphate was injected. An hour later, 6 mL of 8% sodium chloride solution was infused over 30 min in the recovery room while being monitored, and finally, the epidural catheter was removed.	VAS and Odom’s criteria at 1, 3, 6, and 12 months	The back and leg pain significantly decreased during the entire follow-up period after percutaneous epidural neuroplasty. Both short-term and long-term outcomes were positive. These results indicate that percutaneous epidural neuroplasty is an effective treatment for pain in the back and legs caused by a single-level lumbar disc herniation, and the outcomes are not influenced by the type of lumbar disc herniation.
Park et al., 2018 [114]	Retrospective	n = 78	The procedure was performed using a caudal entry approach. After placing the catheter in the appropriate position, a mixture of 10 mL of 0.9% sodium chloride solution and 300 units of hyaluronidase was injected. Another epidurogram was performed, followed by the slow injection of 8 mL of 0.2% ropivacaine and 40 mg of triamcinolone.	VAS, ODI, and SF-12 at 1, 3, 6, and 12 months	During the follow-up period, there was a notable improvement in back and leg pain relief, functional improvement, and overall health. It is possible that extraforaminal contrast distribution during lumbar percutaneous epidural neuroplasty could be linked to enhanced functional outcomes.
Choi et al., 2017 [119]	Retrospective	n = 543 (333 in group I and 210 in group II)	Group I: 5% hypertonic sodium chloride solution injection. Group II: 10% hypertonic sodium chloride solution injection. The caudal approach was used for the procedure, and catheterization was performed after reaching the final catheter position. A total of 5 mL of 0.25% ropivacaine, along with 1500 units of hyaluronidase was injected. Following the confirmation of no complications, 6 mL of 10% or 5% sodium chloride solution was injected, at a rate of 1 mL every 15 min. Subsequently, 2 mL of 0.9% sodium chloride solution containing 40 mg of triamcinolone was injected.	NRS at 1, 3, and 6 months	Both 5% and 10% hypertonic sodium chloride solution injections significantly reduced pain at 1, 3, and 6 months after percutaneous epidural adhesiolysis when compared to pre-procedure levels. However, no significant differences were observed between the 5% and 10% groups during the follow-up period at any point. For patients with concerns about cytotoxic side effects or infusion-related pain, the use of 5% hypertonic saline could be considered as an alternative to the 10% hypertonic saline.

VAS, visual analog scale; ODI, Oswestry disability index; NRS, numeric rating scale; GPES, global perceived effect scale; SF-12, 12-item short-form health survey.