What is Spinal Fusion?
Spinal fusion is a surgical procedure that permanently connects (fuses) two or more adjacent vertebrae into a single solid bone unit. This eliminates painful motion at the fused segments and restores or maintains spinal alignment and stability.
To create fusion, Dr. Huang removes the intervertebral disc, cleans the vertebral surfaces, and places bone graft material between the vertebrae. Metal hardware (screws, rods, plates, or cages) is added to hold the vertebrae in proper alignment while the bone graft fuses—a process typically taking 3–6 months.
Once fusion is complete, no motion occurs between the fused vertebrae. The healthy discs above and below the fusion may move slightly more to compensate, which is normal and usually well-tolerated.
Types of Spinal Fusion Approaches
Dr. Huang uses several approaches to perform spinal fusion, depending on the location of pathology and surgical goals:
TLIF (Transforaminal Lumbar Interbody Fusion)
Most common approach for lumbar fusion. Accessed from the back (posterior), with disc removal and graft placement through the neural foramen. Allows simultaneous decompression and fusion in one procedure.
PLIF (Posterior Lumbar Interbody Fusion)
Also accessed from the back. Disc and graft are placed directly between the vertebrae. Requires wider surgical exposure than TLIF.
ALIF (Anterior Lumbar Interbody Fusion)
Accessed from the front (anterior) of the abdomen. Allows excellent visualisation of the disc space and is used for specific anatomical indications. Requires involvement of vascular surgery.
XLIF/LLIF (Extreme Lateral/Lateral Lumbar Interbody Fusion)
A newer minimally invasive approach accessed through a lateral (side) incision in the flank. Small incisions and potentially faster recovery. Suitable for specific pathology.
Bone Graft Types
Several types of bone graft material can be used to promote fusion:
- Autograft (patient's own bone from iliac crest)—gold standard, highest fusion rate, but requires additional surgery to harvest
- Allograft (donor bone from bone bank)—no harvest surgery, but slower fusion rate than autograft
- Synthetic bone substitutes or bone morphogenetic protein (BMP)—promotes bone formation, used increasingly, but more expensive
- Often, a combination of materials is used to optimise fusion rates
Dr. Huang will recommend the best graft material for your specific situation, balancing effectiveness, safety, and cost.
Who is a Candidate for Spinal Fusion?
Candidates typically have spinal instability, deformity, or progressive neurological deficit that cannot be managed conservatively. Common indications include:
- Spondylolisthesis (slippage of vertebra) causing nerve compression or instability
- Scoliosis or kyphosis requiring deformity correction
- Degenerative disc disease with spinal instability causing recurrent back pain and failed conservative treatment
- Spinal trauma or fractures destabilising the spine
- Spinal tumours requiring vertebral body resection or stabilisation
- Failed previous spine surgery with recurrent instability (revision fusion)
- Adjacent-segment disease following prior fusion
Not all spinal conditions require fusion. Conservative treatment (physical therapy, medications, injections) and non-fusion surgeries (decompression, discectomy) are often tried first. Dr. Huang will recommend fusion only when clearly indicated.
What Happens During Spinal Fusion?
Spinal fusion typically takes 2–5 hours under general anaesthesia depending on the number of levels and complexity. Here is what to expect:
Step 1
Positioning and Exposure
Depending on the approach, you will be positioned prone (back), supine (front), or laterally (side). For posterior approaches (TLIF, PLIF), you are prone. A midline or off-midline incision exposes the vertebrae.
Step 2
Disc Removal (Discectomy)
The intervertebral disc is carefully removed, cleaning out all nucleus pulposus and leaving only the cartilage end-plates for graft contact.
Step 3
Decompression (if needed)
If nerve compression is present, decompression (removal of lamina, ligaments, bone spurs) is performed simultaneously.
Step 4
Graft Placement
Bone graft material is carefully packed into the disc space. If using an interbody cage, it is sized and impacted with graft material inside and around it.
Step 5
Hardware Fixation
Pedicle screws are placed into the vertebrae on both sides of the fusion level(s). Rods, plates, or other constructs connect the screws, creating a rigid frame that holds the vertebrae in proper alignment while bone fusion occurs.
Step 6
Closure
The incision is closed in layers. No additional fusion material is needed—the bony healing over 3–6 months completes the fusion.
Benefits of Spinal Fusion
- Eliminates painful motion between unstable vertebrae
- Restores and maintains proper spinal alignment
- Corrects spinal deformity (scoliosis, kyphosis)
- Prevents progression of spondylolisthesis or instability
- Provides long-term stability and support
- Allows return to normal activities and improved quality of life
Risks and Considerations
- Infection (prevented by sterile technique and antibiotics)
- Bleeding or haematoma
- Nerve root or spinal cord injury
- Dural tear (puncture of membrane around spinal cord)
- Hardware failure (broken or loosened screws or rods)
- Non-union or pseudarthrosis (fusion fails to occur; 5–10% of cases)
- Retrograde ejaculation (anterior fusion approach specific)
- Adjacent-segment disease (accelerated degeneration above or below the fused level) over 5–10 years
- Anaesthesia risks
Serious complications are uncommon. Fusion provides long-term stability and pain relief in most patients, though long-term follow-up is needed to monitor for adjacent-segment disease.
What to Avoid After Spinal Fusion?
Immediate Post-Operative (First 24–48 Hours)
You will stay in hospital for pain control, wound monitoring, and safe mobilisation. Early walking (assisted if needed) is encouraged.
Week 1–2
Back pain and incision soreness are normal. Pain is controlled with prescribed medications. Light activity and walking are encouraged; avoid heavy lifting and bending.
Week 3–4
Gradual return to desk work and light daily activities. Back pain continues to improve.
Week 5–8
Most patients resume normal daily activities. Physical therapy is important to rebuild core strength and flexibility.
Month 3 and Beyond
Return to heavy lifting, manual labour, and intense exercise should be gradual and guided by Dr. Huang. Full recovery and radiological confirmation of fusion typically takes 6–12 months.
Recovery Guidelines Summary
- Avoid heavy lifting (>5 kg) for 6–8 weeks
- Avoid bending, twisting, and repetitive spinal movements for 6 weeks
- No driving until cleared by surgeon (usually 2–4 weeks)
- No high-impact sports or running for 3 months
- Good posture and body mechanics during all activities
- Physiotherapy recommended from weeks 6–8 onwards
Most patients experience significant relief from back pain and instability symptoms within 4–6 weeks. Radiological fusion (bone bridging the gap) typically occurs by 6–12 months, indicating complete healing.
Frequently Asked Questions
Q1: Will fusion restrict my movement?
Fusion eliminates motion only between the fused vertebrae. Adjacent segments above and below continue to move normally. Most patients adapt well and do not notice significant movement restriction in daily activities.
Q2: Will I develop degeneration above or below my fusion?
Adjacent-segment disease (accelerated degeneration above or below the fusion) can occur over 5–10 years in some patients due to increased stress on adjacent discs. However, many patients never develop this problem. Long-term imaging and follow-up with Dr. Huang help monitor this.
Q3: Do I need a brace after spinal fusion?
A brace may be recommended for the first 6 weeks to provide external support while internal fusion is healing. This decision is made based on the extent of fusion and stability of hardware placement.
Q4: How long before my fusion is complete?
Bone fusion typically takes 3–6 months, though radiological evidence of fusion may not be apparent until 6–12 months post-op. During this time, hardware holds the vertebrae in place while bone heals.
Q5: Is fusion better than motion-preserving surgery?
Fusion provides excellent stability for unstable spines. For patients without instability, artificial disc replacement may preserve motion. Dr. Huang will recommend the best approach based on your specific pathology and anatomy.
This is educational content only and does not constitute medical advice. Consult Dr. Huang Yilun for personalised evaluation and recommendations.
To discuss whether spinal fusion is appropriate for your condition, contact Dr. Huang at Total Orthopaedic Care and Surgery, Novena Medical Centre, Singapore. You can also learn more about Dr. Huang's experience with fusion surgery.