Analgesic Effect and Potential Cumulative Benefit from Caudal Epidural D5W in Consecutive Participants with Chronic Low-Back and Buttock/Leg Pain.

Objectives: Chronic low-back pain (CLBP) participants in a prior controlled study reported short-term pain relief after caudal epidural injection of 5% dextrose (D5W). This study assessed whether repeated caudal epidural injections of D5W results in serial short-term diminution of CLBP and progressive long-term decrease in pain and disability. Design: Prospective uncontrolled study. Settings/Location: Outpatient pain clinic. Subjects: Adults with CLBP with radiation to gluteal or leg areas. Interventions: Caudal epidural injection of 10 mL of D5W (without anesthetic) every 2 weeks for four treatments and then as needed for 1 year. Outcome measures: Numerical Rating Scale (NRS, pain, 0-10 points), Oswestry Disability Index (ODI, disability, %), and fraction of participants with ≥50% reduction in NRS score. Analysis by intention to treat. Results: Participants ( n  = 32, 55 ± 9.8 years old, nine female) had moderate-to-severe CLBP (6.5 ± 1.2 NRS points) for 11.1 ± 10.8 years. They received 5.5 ± 2.9 caudal D5W injections through 12 months of follow-up. The data capture rate for analysis was 94% at 12 months for NRS and ODI outcome measures, with 6% carried forward by intention to treat. A consistent pattern of analgesia was demonstrated after D5W injection. Compared with baseline status, NRS and ODI scores improved by 3.4 ± 2.3 (52%) and 18.2 ± 16.4% (42%) points, respectively. The fraction of participants with 50% reduction in NRS-based pain was 21/32 (66%). Conclusion: Epidural D5W injection, in the absence of anesthetic, resulted in consistent postinjection analgesia and clinically significant improvement in pain and disability through 12 months for most participants. The consistent pattern postinjection analgesia suggests a potential sensorineural effect of dextrose on neurogenic pain.