Low back pain (LBP) is common in adults, with 15-20% of adults experiencing LBP each year and 50-80% of adults experiencing LBP at least once in their lifetime. Various spinal surgeries are being performed to treat LBP, and the number of surgeries is increasing. In a study conducted in the UK in 2017, the number of lumbar spine surgeries doubled over 10 years, and the number of lumbar spine fusion surgeries tripled in the US during a similar period. The situation of Korea is similar. According to 2016 statistics, 323 people per 100,000 people underwent spinal surgery, an average annual increase of 1.2% over the past five years.
Chronic back pain after spinal surgery is common, occurring in 10-40% of patients undergoing spinal surgery. Of these, 80% of patients find it impossible to maintain their jobs, and their quality of life decreases, causing many social and personal problems. As the number of spinal surgeries increases, the number of patients suffering from chronic back pain after spinal surgery and the social cost are expected to increase. Treatment of chronic low back pain after spinal surgery has been attempted with drug therapy, epidural steroid injection, facet joint block and medial branch block, radiofrequency thermal coagulation, epidural adhesiolysis, discoplasty, and spinal cord stimulator. However, a treatment with high medical evidence has not yet been presented.
Erector Spinae Plane Block (ESB) was reported in 2016 by Forero et al. as a treatment for chronic thoracic neuropathic pain and postoperative pain in the thoracic spine. ESPB is performed by injecting a local anesthetic from the end of the transverse process of the spine to the inferior fascial plane of the erector spinae muscle to block the dorsal and ventral rami of the spinal nerves. The injected local anesthetic spreads to the epidural space, paravertebral space, and neural foramina, and there are studies that can spread to the range of 2 to 5 vertebral bodies centered on the injection site. This has the advantage of being easy to perform with a wider range of analgesic effects and less likely to cause serious complications.
ESPB is effective for acute pain relief after various surgeries, including spinal surgery, and cases of positive effects on chronic pain have been reported. ESPB has been studied for pain relief in the thoracic range, but it is gradually expanding its scope to treat LBP. In a case series study targeting patients with various chronic back pain, ESPB showed an analgesic period of more than 20 days. Recently, a randomized controlled trial was published showing that ESPB administered before and after spinal surgery can reduce the intensity and frequency of postoperative LBP. However, published studies on the role of ESPB as a treatment for patients with chronic back pain after spinal surgery have only reported one case study, and no studies have been conducted as RCTs. If the therapeutic effect of ESPB is proven through this study, it will be possible to newly propose ESPB as a simpler and safer treatment for chronic back pain after spinal surgery.

Treatment

For clinical trial subjects who have given informed consent, the patient's condition is evaluated before the procedure, and general monitoring such as pulse oximeter and blood pressure monitoring device is applied. After taking the patient in the prone position, the operator locates the lumbar vertebra at the level of the treatment site under ultrasound-guided and marks the location of the bilateral transverse process (TP). After aseptic disinfection and draping of the treatment area, put a sterile sleeve on the convex-type transducer. Adjust the longitudinal scan of the probe so that the target TP is located in the center of the ultrasound screen. Using color doppler, check whether there is a blood vessel on the needle entry route. Insert a 23G spinal needle by in-plane method to reach the target level of TP. When the needle touches the TP, suction is performed to check the presence of vascular puncture. In the case of the experimental group, 30 ml of 0.13% ropivacaine solution is divided and injected on both sides, and in the case of the control group, 30 ml of normal saline is divided and injected on both sides. The drug solution is prepared in a syringe by a third party unrelated to the procedure and then covered, so that the operator and research subjects do not know it throughout the procedure. After confirming that the erector spinae plane is properly hydrodissected by the drug, the operator removes the needle. Then, after the patient's posture is in the supine position, a nurse or an anesthesiologist blinded to the research group evaluates complications and pain related to the procedure.

Arm Label

Target Number of Participant

Arm Type

Arm Description

30 ml of 0.13% ropivacaine solution is divided and injected on both sides of vertebras

Arm Label

Target Number of Participant

Arm Type

Arm Description

30 ml of normal saline is divided and injected on both sides of vertebras.

Gender

Age

Description

- Chronic low back pain (persistent or recurrent for > 3 months)
- Pain that has occurred or recurred after lumbar spinal surgery    
- After lumbar spinal surgery, if the pain increases compared to before or new low back pain of an unprecedented aspect occurs 
- The pain site coincides with the lumbar spinal surgery site
- Patients who voluntarily gave written consent to participate in this clinical trial       

- Acute pain less than 3 months
- Patients who did not undergo lumbar spinal surgery
- Axial pain in other segments, not axial pain consistent with the area of ​​lumbar spinal surgery
- Complaining of radiating pain as the main pain
- Patients with side effects from local anesthetics, steroids, or contrast agents
- Those who have contraindications to nerve block such as blood coagulation disorder, infection, etc.
- Patients with red flag signs of infection, malignant tumor, vertebral fracture, progressive neurological deficit, cauda equina syndrome, etc.
- Patients with neurological or psychiatric problems
- Pregnancy

NRS (numerical rating scale)

1 month after procedure

NRS (numerical rating scale)

2 weeks and 2 months after procedure

ODI (Oswenstry disability index)

2 weeks, 1 month and 2 months after procedure

PHQ-9 (patient health questionnaire-9)

2 weeks, 1 month and 2 months after procedure

GPE (Global perceived effect)

2 weeks, 1 month and 2 months after procedure