Understanding Failed Back Surgery Syndrome (FBSS)

What is FBSS?

Failed Back Surgery Syndrome (FBSS) is a term used when a person continues to experience significant pain (or develops new pain) after having undergone surgery on the spine intended to relieve back and/or leg pain. According to sources, it is defined as lumbar spinal pain of unknown origin that either persists despite spinal surgery, or appears after surgery in the same anatomical region.

In simpler terms: the surgery did not achieve its intended relief (or relief that lasts), and the person ends up with ongoing pain and disability.

Why the term matters

• It highlights that spine surgery does not guarantee elimination of pain—there are no perfect outcomes.
• It serves as a reminder to patients and clinicians that follow-up care, realistic expectations and multidisciplinary management matter.
• It brings attention to the fact that when surgery is not successful, the remaining care plan becomes more complex.

How common is it?

Estimates vary, but many studies place the incidence of FBSS in the range of 10% to 40% of patients undergoing back surgery.

One systematic review highlighted that estimating the incidence is difficult because of the heterogeneity of the condition (different definitions, different surgeries, different patient populations).

It appears that more invasive surgeries (like open fusions) tend to carry a higher risk.

In short: while many patients fare well after spine surgery, a meaningful subset ends up with persistent symptoms and falls into the FBSS category.

Symptoms & Presentation

When FBSS occurs, patients may present with:

• Persistent back pain or leg pain (or both) – sometimes similar to the pre-surgery pain, sometimes different.
• Sharp, stabbing or burning sensations; numbness or weakness in legs.
• Restricted mobility or decreased function (sitting, standing, walking may all be more difficult).
• Secondary psychological effects: anxiety, depression, sleep disturbance.
• Occasionally the pain may shift location or even be in a region of the spine different from where the surgery was done.

Causes and Contributing Factors

FBSS is not caused by a single issue. Rather it is a multifactorial phenomenon. Some of the key contributors include:

Anatomical / surgical causes:

• Recurrent disc herniation (the operated level or another level).
• Failure of spinal fusion (non-union) or failure of implants/hardware.
• Improper patient selection or surgery at the wrong level.
• Scar tissue (epidural fibrosis) binding nerve roots, causing persistent nerve irritation.
• Adjacent segment degeneration (stress placed on other spinal segments after fusion).

Physiological / neurologic causes:

• Persistent nerve compression or nerve damage before or during surgery.
• Altered biomechanics of the spine after surgery – leading to new sources of pain.

Psychosocial and other factors:

• Patients with depression, anxiety, sleep disturbance, or who are involved in compensation/worker’s-compensation cases may have worse outcomes.
• Chronic pain itself changes the nervous system (central sensitization) making pain more persistent and harder to treat.
• Expectations: when surgery is expected to eliminate pain, and it does not, the disappointment and subsequent stress can worsen outcomes.

Because of this mix of factors, FBSS is described as a “heterogeneous condition”—no two patients will have the exact same mix of causes.

Diagnosis and Evaluation

When a patient continues to have pain after spine surgery, evaluation must be thorough. Some important steps:

• A full history and physical exam: What surgery was done? What symptoms remain? Did the symptoms change?
• Imaging studies: MRI (with or without contrast) or CT, sometimes myelogram, to check for recurrent disc herniation, scar tissue, hardware problems, fusion status, alignment issues.
• Electrophysiological tests (EMG) to assess nerve function.
• X-rays to check spinal alignment, hardware position, fusion status.
• A psychosocial assessment: Sleep, mood, function, coping mechanisms—these matter for the overall picture.
• Diagnostic injections or blocks may also be used to localize pain generators (e.g., facet joints, nerve roots).

Importantly: just because surgery was done does not mean all plausible causes have been corrected—the diagnostic process in FBSS remains complex, and sometimes the cause is elusive.

Treatment Options and Management

Given the complexity of FBSS, treatment is multimodal. Some of the approaches include:

Conservative therapies:

• Physical therapy (focused on improving mobility, strengthening the core/spine supporting muscles, posture).
• Pain-management medications (non-opioid analgesics, neuropathic pain medications).
• Injections: epidural steroid injections, nerve blocks, facet joint injections.
• Lifestyle modifications: weight management, smoking cessation, ergonomics, activity modification.
• Psychological support: cognitive behavioural therapy, pain-coping strategies, addressing mood/sleep disorders.

Advanced therapies:

• Spinal cord stimulation (SCS): For appropriately selected patients, SCS has been shown to provide relief and may be superior to repeated surgery in some settings. ^[19][9]
• Revision surgery: In select cases where a clear anatomical cause is found (e.g., hardware failure, recurrent disc herniation at the same level, mal-alignment), a second surgery may be considered—but outcomes decline with each subsequent surgery.
• Other interventional pain procedures: e.g., epidural lysis of adhesions (for scar tissue), radiofrequency ablation of facet joints, etc.

Key point: The goal is not always “complete elimination of pain,” but improving function, reducing pain intensity, enhancing quality of life, and restoring activity as much as possible.

Why Prevention & Patient Selection Matter

One of the lessons from FBSS is that the best outcome is to avoid it in the first place where possible. This includes:

• Ensuring surgery is truly indicated—i.e., the pain source is well identified, conservative treatment tried, patient is optimized medically/psychologically.
• Minimally invasive techniques when appropriate (reducing damage and scar tissue).
• Managing expectations: surgery may help anatomy, but may not completely relieve pain, especially if there are secondary pain generators or central sensitization.
• Pre-operative optimization: controlling comorbidities (diabetes, obesity, smoking), screening for mood disorders, ensuring realistic goals.

Living with FBSS: What Patients Can Do

For those diagnosed with FBSS, here are some practical strategies:

• Stay active, within limits: Gentle movement and PT can help prevent deconditioning.
• Manage mood and sleep: Poor sleep and depression worsen chronic pain—seek help.
• Readjust expectations: The goal may shift from “pain-free” to “pain managed and active.”
• Healthy lifestyle: Good nutrition, smoking cessation, healthy weight reduce stress on spine.
• Work with a multidisciplinary team: Spine surgeon, pain specialist, physical therapist, psychologist.
• Explore advanced options: If conservative care is insufficient, ask about SCS or other interventional options.

It illustrates the emotional and functional toll this condition can bring—but also underscores the importance of second opinions and broader care strategies.

Conclusion

Failed Back Surgery Syndrome is a challenging and often under-appreciated outcome of spinal surgery—the persistence or recurrence of pain despite intervention. While the term may sound grim, it doesn’t mean hopeless: a combination of careful evaluation, realistic expectations, non-surgical therapies, and in selected cases advanced interventions such as spinal cord stimulation, can help many patients regain function and quality of life.

If you or someone you know is dealing with ongoing pain after spine surgery, it’s important to seek care at a center familiar with FBSS, explore all non-surgical options, ask about conservative vs invasive paths, and ensure the full landscape—physical, psychological, functional—is being addressed.