Failed Back Surgery Syndrome, Sciatica and Disc Pain

Failed back surgery syndrome is persistent pain after spinal surgery, and it rarely has a single cause. Dr. Ashu Kumar Jain, Chief – Pain Medicine & Palliative Care, Artemis Hospitals, Gurugram, India, finds the source level by level: the nerve below the fixation, a nerve trapped in scar, the joint above the fixation or the sacroiliac joint, each treated with a targeted procedure.

The same diagnostic discipline applies to the unoperated back. Sciatica, facet joint pain and disc pain each have a different generator and a different treatment. This article covers the lower back and legs, then the knee and heel. The broader principles, safety record and costs are set out in the interventional pain management guide.

Two kinds of low back pain

Dr. Jain separates low back pain into two clinical pictures, because they lead to different procedures.

• Pain that travels down the leg (sciatica or radicular pain) usually comes from a disc or a narrowed canal irritating a nerve root.
• Pain that stays in the back (axial pain) comes mostly from the facet joints of the spine or from the disc itself.

The history of where the pain goes is therefore the first step in choosing a treatment.

Sciatica: epidural injection and nerve release

When a disc is causing pain down the leg without a neurological deficit, Dr. Jain treats the patient with epidural injection rather than surgery. His estimate is that 70 to 80 per cent of back pain that travels down the legs can be managed without surgery.

The injection is delivered under imaging into the epidural space of the lumbar spine, the space around the nerve roots inside the spinal canal, so that the medication reaches the irritated nerve root. Where the nerve is trapped, he goes further and releases it. He showed a procedure in which contrast first outlines the nerve (neurography), and the nerve is then freed under imaging; he described the results in sciatica as very good. Freeing a nerve from surrounding adhesions through a needle or catheter is known as adhesiolysis.

A caudal epidural injection, given through the sacral hiatus at the base of the spine, is another route into the epidural space. Dr. Jain uses it in patients whose pain has returned after back surgery with screws in place.

Facet joint pain in the lower back

When pain stays in the back, it comes mostly from the lumbar facet joints or from the disc. If the pain is confirmed to come from the joints, he performs lumbar facet radiofrequency ablation (RFA), which interrupts the small nerves that carry pain from the joints.

The importance of this step is diagnostic as much as therapeutic. Facet joint pain does not compress a nerve, so it is confirmed by targeted testing of the joints rather than by a scan alone. Once confirmed, the same joints become the treatment target.

Failed back surgery syndrome: four sources, four treatments

Failed back surgery syndrome has four distinct sources of pain in Dr. Jain's description, each with its own procedure. This is where his level-by-level method is most visible: a patient can be technically well after a fusion and still have pain.

1. The nerve below the fixation. When pain begins after surgery at the level below the fused segment, he performs an epidural injection at that level.
2. A nerve trapped in scar tissue. In one patient the surgery itself had gone well, but pain was travelling down the legs. Imaging showed the nerve entrapped in post-operative scar. He opened up the nerve through the needle-based procedure, and the patient was perfectly fine afterwards.
3. The facet joint above the fixation. Fusion transfers load to the segment above. When pain arises from the facet joint above the level of fixation, he ablates that joint with RFA.
4. The sacroiliac joint. Pain can begin in the buttock joint after fixation, and he treats this with RFA of the sacroiliac joint.

His summary was that pain can occur anywhere after surgery, and it can be treated there. For the referring doctor, the implication is that a patient with persistent pain after spinal surgery should not be assumed to need another operation. The pain generator needs to be found first.

Sacroiliac joint pain: rarely diagnosed, readily treated

The sacroiliac joint, which links the base of the spine to the pelvis, is in Dr. Jain's experience one of the least diagnosed sources of back and buttock pain, and patients can suffer from it for long periods. He treats it with either of two procedures:

• a joint injection, with contrast confirming that the medication is inside the joint;
• radiofrequency ablation of the nerves supplying the joint.

He uses the same approach whether or not the patient has had previous spinal surgery.

Discogenic back pain: cooled radiofrequency of the disc

Some patients have back pain that comes from the disc itself rather than from the joints or a nerve root. The pain stays in the low back and does not travel to the legs. Typically the patient cannot stand for long and cannot sit for long. The disc is painful but is not causing any significant compression.

For this group, Dr. Jain uses cooled radiofrequency ablation of the disc, which he describes as the most advanced technique available for pain arising from the lumbar disc. A probe is introduced into the disc under imaging and radiofrequency energy is applied, with the probe cooled so that a controlled lesion forms within the disc. Intradiscal cooled radiofrequency of this kind is commonly known as biacuplasty.

He reports that the pain can be treated in 80 per cent of these patients.

Choosing a procedure for the lower back

Knee pain when surgery is not an option

Dr. Jain treats the knee in stages that follow the severity of the arthritis.

• Early osteoarthritis: regenerative therapy with platelet therapy (platelet-rich plasma, PRP) or stem cell therapy.
• Advanced disease, or failure of regenerative therapy: cooled radiofrequency ablation of the knee, which interrupts the sensory nerves around the joint (the genicular nerves). He considers it one of the best techniques available for knee pain that is not responding to other treatment. The American College of Rheumatology's 2019 osteoarthritis guideline recommends against platelet-rich plasma and stem cell injections for knee osteoarthritis, citing insufficient evidence.

The patient he chose to illustrate this had heart disease and was on blood thinners, which ruled out a knee replacement. After cooled RFA, with supportive treatment, she was able to return to work. For patients who cannot undergo, or do not want, total knee replacement, cooled RFA offers a non-surgical route to pain relief.

Heel pain, tendons and muscles

Dr. Jain treats heel pain either with regenerative therapy or with an interventional procedure. More broadly, his team performs ultrasound-guided regenerative therapy for muscular pain and tendinopathies. Ultrasound shows the tendon and the needle in real time, so the injection reaches the damaged tissue.

When to refer back and leg pain to a pain specialist

Three points from this part of the session matter most for doctors deciding where to send a patient with back or leg pain.

1. Neurological deficit decides surgery. Pain alone, even severe pain from a disc, is usually treatable without an operation when there is no weakness.
2. After surgery, find the level. Persistent pain after fusion has at least four possible sources, and each is treated differently.
3. Unfit for surgery is not untreatable. Patients on blood thinners or with heart disease, like the knee patient above, often still qualify for a day-care procedure.

Sympathetic causes of leg pain, including diabetic foot, Buerger's disease and phantom limb pain, are treated through the lumbar sympathetic chain and are covered in percutaneous sympathectomy, visceral nerve blocks and pumps. Neck and shoulder pain are covered in cervicogenic headache, facial and neck pain without surgery. Dr. Jain's later masterclass also addressed this region, in back pain treatment without surgery. Questions doctors asked at the end of the June 2025 session are in the Live Discussion.