Scoliosis is not an uncommon condition in children and adolescents.
Globally, about 1.65% to 3.1% of those between the ages of 10 and 18 years experience this spinal misalignment.
The cause in the majority of cases is unknown, i.e. idiopathic.
This abnormal, lateral (side-to-side) curvature of the spine, forming an “S” or “C” shape, is frequently diagnosed during growth spurts.
Typical signs include uneven shoulders, asymmetrical waist, rib prominence on one side or postural changes.
“We know it is usually on the right side of the thoracic spine, affects mostly girls, often runs in families, and is a painless condition,” says consultant orthopaedic and spine surgeon Dr Wong Chung Chek.
“The person might be walking and may not feel anything until someone notices the back is curved to one side.
“Or when a teenage girl wears tight clothing, her scoliosis can be picked up.”
Curving more and more
Early detection is crucial as scoliosis can progress and lead to severe complications later in life.
Specialists will usually take an X-ray of the spine and measure its curvature.
Dr Wong says: “The definition of scoliosis is an angle measurement of 10°, but in the thoracic spine, most doctors accept a curve of 40° before talking about surgical intervention.
“Why we choose this number before surgical intervention is because we know scoliosis is due to the growth spurt, which will stop around the ages of 19 or 20, and the curve will not increase further.”
Scoliosis progression can be influenced by several factors, including the severity of the curve, the child’s age and treatment approach.
While bracing can help stabilise the spine, it is not a cure, as in some cases, the spine can continue to worsen despite intervention.
However, studies show that if the curve is more than 40°, certain children will see their condition continue to worsen, even when they stop growing.
This magnitude of deformity will compress on one side of the spine, potentially leading to pain, breathing difficulties and other complications.
Dr Wong says: “We measure every three months, so when they come in at 20° curvature, we treat them with physical therapy, bracing or something to slow down the progression.
“Once it curves past 40°, the cartilage gets overloaded and starts wearing out the disc.”
Studies also predict that the curvature will increase one degree a year.
“When the angle hits 70°, the spine is so curved that it starts to affect the lung function where one lung is compressed and the other is too inflated, but there is still no pain.
“The gasses [oxygen and carbon dioxide] exchange is impacted and the patient will find climbing one flight of stairs exhausting, i.e. effort intolerance, and eventually, it will affect the heart function,” he explains.
For an 18-year-old with a spinal curvature of 50°, it is predicted that their curve will be 72° by the time they reach 40 years of age.
Hence, early surgical intervention is necessary.
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Fusing the bones
The traditional surgical method of treating scoliosis in a patient who has pretty much achieved their growth potential involves spinal fusion.
This is a procedure where two or more vertebrae are permanently joined to prevent further progression of the spinal curve.
It involves the use of bone grafts and metal implants, such as rods and screws, to join selected vertebrae.
“Basically, it’s like a welding process so that the bone does not move any more and the scoliosis will not worsen,” says Dr Wong.
“We fuse T5 to T11 of the thoracic bones, or if the child has another curve in the lumbar area, we also fuse that area.
“This makes the spine stiff, and when the fusion has occurred in a few months, we take the metal rod out.
“Slowly, and with better technology, we are perfecting the science of doing fusion, but it’s still fusion and that means only the vertebrae that is not fused will continue to move (and grow).”
He points out that in the lumbar spine (lower back), the 40° curve criteria does not apply as even a 30° curve can worsen rapidly.
Unlike the thoracic spine (upper back), which does not move very much, the lumbar area is more flexible and takes on more load.
Untreated lumbar scoliosis brings forth a new set of problems later, such as pinched nerves (sciatica), disc degeneration, osteophyte (bone spur) formation, etc.
“Then it’ll be a much bigger operation (which involves fusing the thoracic spine to the lumbar spine) and is more restrictive, so you can only turn your body like a robot as there will be hardly any movement in the spine.
“If we treat the lumbar scoliosis earlier, then the patient won’t have this dilemma, but with fusion, there will be no motion preservation in this area, so it is challenging for doctors to make a decision,” Dr Wong says.
Providing tension
In 2019, the United States Food and Drug Administration (FDA) approved the use of vertebral body tethering (VBT).
This is something Dr Wong had been eagerly awaiting.
This minimally-invasive surgical procedure for idiopathic scoliosis in growing children corrects the spinal curvature, while preserving growth and spinal motion.
During the surgery, thoracoscopic technology is used to attach screws to the convex side of the spinal vertebrae and connect them with a flexible cord called a tether.
The tether (made of polymer material) is tensioned to partially straighten the spine, and this tension restricts the growth of the convex side, while allowing the concave side to continue growing, thus gradually correcting the scoliosis.
Dr Wong is one of the few local doctors who has been using this method since late 2024 and is thrilled with the results.
He says: “Anything that can move can break, so that’s why motion preservation technology was so difficult to come by until this gamechanger.
“The VBT screws come with a special coating that enables them to grow into the bone.
“Unlike fusion surgery where the screws can loosen, here it doesn’t happen.
“The side effect of VBT is overcorrection, so we have to assess the child’s growth potential first before deciding how much to correct.
“If there is an overcorrection, we go in and cut the tether, but I haven’t seen that happen yet.”
The tether may also break in the future, but once the spine has been straightened, that is not a problem.
He adds: “It will show in the X-ray, but the patient doesn’t feel anything, while if the metal rod breaks after the fusion surgery, the patient will experience sharp pain.”
The tether comes in one size, but the screws are of different sizes.
“If the adult patient hasn’t developed any problems, then we can use VBT on them to correct the lumbar area.
“In bigger size patients, we put in two screws and two tethers as the lumbar area needs sturdier support,” says Dr Wong who now spends half his time doing VBT.
Back or front?
VBT is available in both local private and public hospitals, depending on whether doctors are comfortable using the anterior approach.
The choice between anterior and posterior approaches in spine surgery depends on the specific spinal condition and the surgeon’s expertise.
Anterior approaches are often preferred for lumbar spinal fusion due to their ability to preserve back muscles and promote faster recovery.
Traditional posterior approaches are effective for certain spinal issues and provide a clearer view for precise repairs.
But because it requires navigating through or around back muscles, it can lead to muscle injury and pain.
Both approaches have their merits, and the decision is made based on the individual patient’s anatomy, pathology and any associated illnesses.
“With posterior surgery, we have to scrape out all muscles from the spine, but here, we make four small incisions, use a scope and pass it through, so we don’t need to cut any muscles.
“And when we remove the scope, the muscle will close itself.
“The patient can go home the next day – the pain is treatable and the results can be seen immediately as they walk straighter,” explains Dr Wong.
The recovery time is relatively short, and most patients can resume daily activities within a few weeks to a few months.
Regular follow-up visits are necessary to assess the correction results and the condition of the hardware.
The surgeon, who is now in private practice, notes that he typically performed about 50 scoliosis surgeries a year on adolescents when he was in public service.
His message to parents: “Come and consult us if your child has scoliosis and still has growth potential.”
