Principal Director, Orthopaedics, Fortis Flt. Lt. Rajan Dhall Hospital, Vasant Kunj, New Delhi
Part 7 of 8 in Adolescent Idiopathic Scoliosis
Surgical Correction: From the Harrington Rod to Modern Pedicle Screw Fixation
August 4, 2024
Surgical correction of AIS has evolved considerably. The earliest widely-used system, the Harrington rod, distracted the concave side of the curve using hooks at the top and bottom vertebrae, but it couldn't correct the rotational component of the deformity, left the ribs prominent, and carried a real risk of neurological injury from over-distracting the spinal cord.
From sublaminar wiring to pedicle screws
A later modification used Luque rods with sublaminar wiring at each vertebral level, an improvement, but with its own risks of dural injury, CSF leaks and neurological deficit, and it still couldn't properly control rotation or provide truly solid fixation in more severe deformities. The modern standard, the Cotrel-Dubousset (CD) system and its successors, uses pedicle screws at most involved vertebral levels with dual rods, applying compression on the convex side and distraction on the concave side, plus a derotation manoeuvre at the curve's apex. This achieves solid three-column fixation through the posterior, middle and vertebral body columns, correcting rotation properly, not just coronal-plane bending, and requires no post-surgical brace.
Anterior instrumentation and growth-friendly options
Anterior instrumentation, approaching the spine from the front to compress screws placed in the vertebral bodies, achieves better rotational correction with fewer fused levels for thoracolumbar curves specifically, but is used less often worldwide due to approach-related complexity; posterior fixation remains the mainstay for most cases. A newer growth-friendly option uses a flexible anterior cord with screws near the apex to restrict growth on the convex side without fusing the spine, useful for flexible curves that correct well on bending views, since it lets the spine keep growing while the deformity is controlled.
This article is based on a Jivo Masterclass session conducted by Dr. Manoj Miglani, Principal Director, Orthopaedics, Fortis Flt. Lt. Rajan Dhall Hospital, Vasant Kunj, New Delhi. The article has been summarised with the assistance of an AI tool from the original masterclass recording. Watch the full Masterclass recording
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This guide is based on a live Jivo Masterclass: Dr. Manoj Miglani taught doctors across Africa on August 4, 2024.
FROM THE LIVE Q&A
Dr. Michael
For a patient being observed with a curve between 10 and 20 degrees, is it okay to start some physiotherapy or rehabilitation exercises, or does one have to wait?
Dr. Manoj Miglani
At 10 to 20 degrees, the focus should just be on exercises to keep the back muscles healthy and avoiding extremes of posture, that is all that is needed. Follow-up frequency with X-rays, whether every 3 months, 6 months or a year, depends on the child's age and Risser sign, not on whether they are doing exercises.
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Frequently Asked Questions
You said between 3 to 6 months for the X-ray follow-up. Can you clarify how that's decided?▼
If the child is young, say 10 years old with a 20-degree deformity, X-rays should be done every 3 months since they are likely to progress more. If the child is 13-14 years old with the same 20-degree curve, X-rays every 6 months to a year are enough, just to confirm the deformity isn't progressing rapidly.
Is there any preventive treatment, such as exercises, bed positioning or diet, that can help avoid developing scoliosis or keep it from progressing?▼
No, there are no preventive measures for idiopathic scoliosis, because the actual cause isn't known. The only genuinely useful advice is for the child to stay physically active, which most children naturally are.
Is there a difference between true scoliosis and scoliosis attitude?▼
Yes. Scoliotic attitude is purely a postural thing, not a structural curve. A true structural curve is distinguished from a postural presentation using standing X-rays and bending views, which show whether the curve is rigid or fully correctable.
As a traumatic scoliosis patient from DRC with a Cobb angle of 22 degrees, should I wear a custom-made corset or a removable corset with physiotherapy sessions?▼
At a Cobb angle of 22 degrees, correction may not be needed at all. If there is no pain in the affected area of the spine, the curve is unlikely to progress further and has likely already stabilised, so no bracing or active intervention is required. X-ray pictures and clinical photos would be needed for a fuller review of the specific case.
Can you say something regarding intraoperative monitoring during operative treatment of AIS?▼
Intraoperative neuromonitoring is used routinely for curves more than 60-70 degrees, which makes the surgery much safer. The monitoring system stays active throughout the procedure, with checks after every screw placement and after every corrective manoeuvre, which is what keeps neurological complication rates under 1%, even for nerve root injury.
What was the problem with the Harrington rod system?▼
It couldn't correct the rotational component of the deformity, left the ribs prominent, and carried a real risk of neurological injury from over-distracting the spinal cord.
What is the modern standard for scoliosis surgical correction?▼
The Cotrel-Dubousset (CD) system and its successors: pedicle screws at most involved levels with dual rods, compression/distraction and a derotation manoeuvre, achieving solid three-column fixation without needing a post-surgical brace.
In This Series: Adolescent Idiopathic Scoliosis
- 1.Adolescent Idiopathic Scoliosis
- 2.What Is Adolescent Idiopathic Scoliosis? Epidemiology and the Unknown Cause
- 3.Diagnosing and Classifying Scoliosis: Cobb Angle, Curve Types and True vs Postural Deformity
- 4.The Risser Sign: Predicting Whether a Scoliosis Curve Will Progress
- 5.Treatment Thresholds: Observation, Bracing and Surgery by Curve Severity
- 6.Why Bracing Has Real Limits: Brace Types, Compliance and When It Fails
- 7.Surgical Correction: From the Harrington Rod to Modern Pedicle Screw Fixation
- 8.Scoliosis Complications: Untreated Progression, Surgical Risk and a Post-Traumatic Case