This study will be held on patients with failed back surgery syndrome, the investigators are comparing prolotherapy and steroids injections in caudal epidural space to relieve the pain

This study is a prospective double blinded randomized controlled study. It will be held on patients with failed back surgery syndrome aged between 20 and 70 years old, one group will receive ultrasound and fluoroscopy-guided injection of prolotherapy in caudal epidural space while the other group will receive ultrasound and fluoroscopy-guided injection of steroids in the caudal epidural space 40 patients will be included in each group

Inclusion Criteria:

1. patients diagnosed with failed back surgery syndrome, having chronic pain for more than 3 months by a detailed assessment including medical history and examination
2. patients having positive radiological (MRI) findings of spinal nerve roots being irritated or compressed after having surgery for one of many conditions including: lumbar disc herniation, spinal canal stenosis, osteophytes, spodylolithesis or foramen stenosis
3. patients whom another surgery is not indicated

Exclusion Criteria:

1. patient refusal
2. pregnancy
3. systemic infection or infection at the site of injection
4. patients on anticoagulation
5. immunocompromised patients as uncontrolled diabetes, osteoporosis as a contraindication for steroid injection
6. patients with renal impairment or on dialysis
7. acute disc prolapse as it requires immediate surgery
8. opioid use
9. concurrent significant depressive illness, inflammatory of joint disease.

there is a plan to make individual participant data (IPD) collected in this study, including data dictionaries, available to other researchers

After study ends upon request

Accessible through the web site

Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) double blinded