Possible causes

1. New or recurrent nerve compression
   • A recurrent disc herniation at an operated level, or a new disc problem at another level.
   • Narrowing of the spinal canal or nerve exits, called lumbar spinal or foraminal stenosis. Pain provoked by walking can sometimes reflect neurogenic claudication from stenosis, particularly if it improves when sitting down or bending forward.
2. Degenerative changes below or beside the operated levels
   • Your surgery was at L2-3 and L3-4, but pain felt in the lumbosacral area can arise from lower discs, facet joints, or the sacroiliac joints.
   • Facet-joint arthritis, disc degeneration, spondylolisthesis, or instability can cause mechanical pain that is worse with prolonged standing, walking, or sitting.
3. Postoperative changes
   • Epidural scar tissue, recurrent/residual disc material, or less commonly post-surgical instability may cause recurrent pain. In people with persistent or recurrent pain after spinal surgery, contrast-enhanced MRI is commonly used to distinguish recurrent disc material from postoperative scar. Grainger & Allison's Diagnostic Radiology, p. 127? (postoperative-spine section; exact pagination varies by edition).
4. A separate coccyx problem, or coccydynia
   • Coccyx pain is often worse with prolonged sitting and rising from sitting. It may follow direct trauma, repeated pressure from awkward sitting, coccygeal hypermobility, or pelvic-floor muscle dysfunction. Sitting and standing coccyx X-rays may sometimes help identify abnormal coccyx movement. Campbell’s Operative Orthopaedics, coccygeal pain section.
5. Less common but important causes
   • Sacroiliac joint inflammation, compression fracture, infection, cancer, or an inflammatory spinal disorder. These cannot be excluded from symptoms alone.

What evaluation would be reasonable

• A focused neurologic and musculoskeletal examination: leg strength, reflexes, sensation, gait, nerve-tension testing, hip and sacroiliac-joint examination, and coccyx tenderness.
• Lumbar MRI, usually with and without contrast, if your surgeon/radiologist considers it appropriate. This can assess recurrent/new disc disease, stenosis, nerve compression, infection, and postoperative scar.
• Standing lumbar X-rays, sometimes including flexion-extension views, if instability or vertebral slippage is suspected.
• If tailbone pain is clearly separate and triggered by sitting, standing and sitting lateral coccyx X-rays and occasionally MRI of the sacrum/coccyx.
• Blood tests only if symptoms or examination raise concern for infection, inflammatory disease, or malignancy.

Treatment depends on the cause

• Activity modification, not prolonged bed rest: temporarily reduce steep trekking, heavy packs, repetitive bending/twisting, and long uninterrupted sitting. Use gradual pacing instead of pushing through severe pain.
• Targeted physiotherapy: trunk endurance and hip strengthening, graded walking, mobility work, gait and backpack-load assessment, and movement retraining. If coccyx symptoms are prominent, pelvic-floor physiotherapy may be helpful.
• Ergonomics: lumbar support, frequent position changes, avoiding long static sitting, and for coccyx pain a cut-out coccyx cushion rather than a standard donut cushion.
• Medication: a clinician may consider acetaminophen, a short NSAID course if safe for you, topical anti-inflammatory medication, or treatment directed at neuropathic pain if there is burning, tingling, or radiating leg pain. Avoid self-starting prolonged NSAIDs if you have kidney disease, ulcers, are on blood thinners, or have cardiovascular risk.
• Image-guided diagnostic or therapeutic injections: depending on the examination and MRI, this may include an epidural injection for nerve-root inflammation, facet-joint medial branch blocks, sacroiliac injection, or coccyx/ganglion impar injection. These are most useful when there is a specific suspected pain generator, not as a substitute for diagnosis.
• Surgery: revision decompression or stabilization is considered only when imaging and symptoms clearly match a surgically correctable cause, such as major recurrent disc herniation, severe stenosis with neurologic compromise, or instability. Repeat surgery is not automatically the best answer for nonspecific axial back pain.

Seek urgent assessment now or emergency care if you have

• New leg weakness, foot drop, repeated falls, or rapidly worsening ability to walk
• Numbness in the saddle/genital area
• New urinary retention, loss of bladder/bowel control, or fecal incontinence
• Fever, unexplained weight loss, history of cancer, IV drug use, or severe pain at rest/night
• Significant trauma, or severe unremitting pain