Persistent spinal pain syndrome

Lore & Background

Persistent spinal pain syndrome (PSPS) is a medical classification for chronic pain originating in the spine. Type 1 applies to patients who have not undergone surgery, while Type 2 applies to those who have had one or more spinal surgeries. PSPS type 2 replaces the older term 'failed back surgery syndrome' (FBSS), which is now considered medically inadequate and potentially pejorative. Many factors can contribute to the onset or development of FBSS, including residual or recurrent spinal disc herniation, persistent post-operative pressure on a spinal nerve, altered joint mobility, joint hypermobility with instability, scar tissue (fibrosis), depression, anxiety, sleeplessness, spinal muscular deconditioning, and Cutibacterium acnes infection. An individual may be predisposed by comorbid systemic diseases, including diabetes, autoimmune diseases, and peripheral vascular disease.

Common symptoms include diffuse, dull, and aching pain in the back or legs, often accompanied by abnormal sensations such as sharp, pricking, or stabbing pain in the extremities. Patients may also experience pain at a different level from the location originally treated, along with an inability to fully recuperate and restricted mobility. Sharp, stabbing pain in the back, numbness, muscle spasms, or pain radiating from the lower back into the legs are frequently reported. Psychological symptoms such as anxiety, depression, and insomnia are also common.

The number of spinal surgeries varies around the world. The United States and the Netherlands report the highest number, while the United Kingdom and Sweden report the fewest. Success rates vary. Patients who continue to experience pain after surgery can be divided into two groups: those in whom surgery was not actually indicated or technically did not achieve the intended result, and those who had incomplete or inadequate operations. Lumbar spinal stenosis may be overlooked, and removal of a disc while not addressing stenosis can lead to disappointing results. Operating on the wrong level or failure to recognize an extruded disc fragment can occur. In 1992, Turner et al. published a survey of 74 journal articles reporting results after decompression for spinal stenosis; good to excellent results were reported by 64% of patients on average, with wide variation. Herron and Trippi evaluated 24 patients with degenerative spondylolisthesis treated with laminectomy alone; 20 out of 24 reported a good result at follow-up. Epstein reported on 290 patients over 25 years, with excellent results in 69% and good results in 13%. These optimistic reports do not correlate with 'return to competitive employment' rates, which are dismal in most spinal surgery series.

In the past two decades, there has been a dramatic increase in fusion surgery in the U.S. In 2001, over 122,000 lumbar fusions were performed, increasing to an estimate of 250,000 in 2003, and 500,000 in 2006. For patients with continued pain after surgery not due to complications, interventional pain physicians speak of identifying the 'pain generator.' It is often not possible to determine the source of pain because many patients have disc bulges at multiple spinal levels, and physical examination and imaging studies are unable to pinpoint the source. Spinal fusion itself may result in 'adjacent segment degeneration' due to increased torsional and stress forces on discs above and below the fused vertebrae. Another consideration is the increasing recognition of 'chemical radiculitis' in the generation of back pain. It is increasingly recognized that back pain may be due to chemical inflammation of the nerve root, mediated by tumor necrosis factor-alpha (TNF), rather than solely compression. If the cause is inflammation mediated by TNF, surgery might not relieve the pain and might even exacerbate it.

The sacroiliac joint (SIJ) is a pain generator in an estimated 15% to 25% of patients with axial lower back pain. Studies show that the incidence of SI joint degeneration in post-lumbar fusion surgery is 75% at 5 years post-surgery based on imaging, and 40–61% of post-lumbar fusion patients were symptomatic for SI joint dysfunction based on diagnostic blocks. Cigarette smoking is associated with failure of spinal surgery; many surgeons consider smoking an absolute contraindication. Nicotine appears to interfere with bone metabolism and may restrict small blood vessel diameter, leading to increased scar formation. Postoperative smoking cessation has a positive impact on success.

Reader's Guide

Persistent spinal pain syndrome (PSPS) represents a significant evolution in the classification of chronic spinal pain, moving away from the potentially pejorative term 'failed back surgery syndrome' (FBSS) to a more neutral, descriptive framework under ICD-11. This change reflects a growing understanding that chronic pain after spinal surgery is not simply a 'failure' of the patient or surgeon, but a complex condition with multiple contributing factors, including residual disc herniation, nerve root inflammation, joint instability, scar tissue, and psychological comorbidities. The distinction between PSPS-T1 (no prior surgery) and PSPS-T2 (post-surgical) allows for more precise diagnosis and treatment planning.

The condition's significance is underscored by the high volume of spinal surgeries worldwide, particularly in the United States and the Netherlands, and the dramatic increase in fusion surgeries over the past two decades. Despite surgical advances, outcomes vary widely, with many patients not returning to competitive employment. The recognition that pain may be driven by chemical inflammation (e.g., tumor necrosis factor-alpha) rather than mechanical compression alone challenges traditional surgical approaches and highlights the need for multidisciplinary management. Additionally, the role of the sacroiliac joint as a pain generator in 15–25% of axial lower back pain patients, and the high incidence of SI joint degeneration after fusion, points to often-overlooked sources of persistent pain. Smoking's negative impact on surgical outcomes further complicates treatment. PSPS thus serves as a reminder that chronic spinal pain requires careful, individualized assessment and that surgery is not always the definitive solution.

Did You Know?

• PSPS type 2 replaces the older term 'failed back surgery syndrome' (FBSS), which is now considered medically inadequate and potentially pejorative.
• The United States and the Netherlands report the highest number of spinal surgeries, while the United Kingdom and Sweden report the fewest.
• In 2001, over 122,000 lumbar fusions were performed in the U.S., increasing to an estimated 500,000 in 2006.
• Cigarette smoking is considered by many surgeons to be an absolute contraindication to spinal surgery.