AB267. SOH26AB_0069. Case report of ultrasound-guided hydrodissection: a novel treatment approach in treating S1 nerve root pain

Background: Little is known regarding the use of hydrodissection in the management of S1.

Case Description: Female patient presented with chronic severe left lower limb pain. Her magnetic resonance imaging (MRI) showed a broad-based disc bulge at L5–S1, canal stenosis, and S1 nerve root impingement. There was a background of L5–S1 discectomy. Her pain had not responded to conservative management such as physiotherapy or traditional analgesics. The most common area to be affected by this pain and radiculopathy is L4–L5; however, the second most common is L5–S1, which presents with pain, reduced power, and sensation to the posterior thigh, calf, and foot. Dynamic ultrasound scanning was performed to identify the structures in the region. The skin was prepared using chloroprep, and ultrasound guidance was used throughout until the needle was positioned at the S1 foramen. After confirming the needle tip position, 10 mL of 5% dextrose was injected for hydrodissection and with good visualization of the distribution of the injectate solution. A sustained analgesic effect was reported when followed up in the pain clinic outpatient department (OPD) at 6 weeks. The patient reported significant analgesic benefit. This is the first application of ultrasound-guided hydrodissection to target specifically the S1 nerve root. It offers a novel, safe, and effective technique to aid in the diagnosis and treatment of a common pain condition, which could reduce the use of opioids, non-steroidal anti-inflammatory drugs (NSAIDs), and hospital admissions for chronic low back pain with radiculopathy.

Conclusions: To our knowledge, ultrasound-guided hydrodissection has not yet been described as a treatment approach specifically at the S1 nerve root. In our patient’s case, it was an effective pain-relieving therapy, but more studies are needed to evaluate its efficacy.

Keywords: Hydrodissection; lower limb pain; pain; S1 nerve; case report